connaect 2010

THE MAGAZINE OF THE GLOBAL BBR NETWORK OF EXPERTS

Golden Strands50thAnniversary feature

Evolution of stay cable technologyand application across 400 projects

www.bbrnetwork.com Fourth Edition 2010

Win-wind situationGreen energy technology and expertise

Nuclear inspectionInspection and maintenance of

post-tensioning at Swedish power plants

High speed rail projectsBridge construction for Spain’s excitingnew high speed train network

In the public arenaInnovative and durable solutionsfor international stadium and arena projects

Excellencethrough people

How continuing investment in people drivesquality and success within the BBR Network

BBRVT International Ltd is theTechnical Headquarters and Business Development Centre ofthe BBR Network located in Switzerland.The shareholders of BBRVT International Ltd are:BBR Holding Ltd (Switzerland), a subsidiary of theTectus Group (Switzerland); KBSpennteknikk AS (Norway), BBR Polska Sp. z o.o. (Poland) andVORSPANN-TECHNIK GmbH& Co. KG (Austria / Germany), all members of the KB Group (Norway); BBR Pretensados yTécnicas Especiales, S.L. (Spain), a member of the FCC Group (Spain).

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The BBR Network is recognized as the leading group of specializedengineering contractors in the field of post-tensioning, stay cable and relatedconstruction engineering.The innovation and technical excellence, broughttogether in 1944 by its three Swiss founders – Antonio Brandestini, MaxBirkenmaier and Mirko Robin Ros – continues, more than 60 years later, inthat same ethos and enterprising style.From technical headquarters in Switzerland, the BBR Network reaches outaround the globe and has at its disposal some of the most talented engineersand technicians, as well as the very latest internationally approved technology.

THE GLOBAL BBR NETWORKWithin the Global BBR Network, established traditions and strong local rootsare combined with the latest thinking and leading edge technology. BBR grantseach local BBR Network member access to the latest technical knowledge andresources – and facilitates the exchange of information on a broad scale andwithin international partnering alliances. Such global alliances and co-operationscreate local competitive advantages in dealing with, for example, efficienttendering, availability of specialists and specialized equipment or transfer oftechnical know-how.

ACTIVITIES OF THE NETWORKAll BBR Network members are well-respected within their local businesscommunities and have built strong connections in their respective regions.They are all structured differently to suit the local market and offer a varietyof construction services, in addition to the traditional core business of post-tensioning.

BBR TECHNOLOGIESBBR technologies have been applied to a vast array of different structures– such as bridges, buildings, cryogenic LNG tanks, dams, marine structures,nuclear power stations, retaining walls, tanks, silos, towers, tunnels, wastewatertreatment plants, water reservoirs and wind farms.The BBR brands andtrademarks – CONA, BBRV, HiAm, DINA, SWIF and CONNAECT – arerecognized worldwide.The BBR Network has a track record of excellence and innovative approaches– with thousands of structures built using BBR technologies.While BBR’shistory goes back over 60 years, the BBR Network is focused on constructingthe future – with professionalism, innovation and the very latest technology.

Maybe the first thing you will notice about this editionof CONNAECT is that it has grown even larger.This

has happened despite the global financial crisis – because,our international teams have been extremely busy indeed.We have the latest and approved technology, but it is ourpeople – whether in offices or on sites – who make thelight of our excellent technology, know-how and the BBRbrand shine so brightly.

They are able to do this because they are well-informedand can be confident of their specialist knowledge. As wellas taking great care in the selection and continuouseducation of the right team members, we provide manyopportunities for training and encourage a high level ofcommunication within our large global family.

Meanwhile, we continue to develop new technology andsystems to support our people in their work.The rolling-outof our e-commerce platform – BBR E-Trace – places us in aunique position in the industry and represents a significantstep forward in ensuring we continue to work together todeliver the very highest quality of service to our customers.

Thanks to Frau Irma Birkenmaier, who kindly shared somerecollections with us, we can now reflect further and drawinspiration from the sheer dedication and pioneering spirit ofher late husband, one of our founders – Max Birkenmaier.

In the past year, we have also celebrated a milestone in thestay cable arena – we have completed our 400th cable-stayed project and, in 2010, we celebrate the 50thanniversary of our first ever stay cable project. Ourdedication and commitment to quality down the yearsmeans that we now have the greatest and longestexperience in this specialist area – and are looking forwardto creating more records in the future!

1CONNÆCT

THE MAGAZINE OF THE GLOBAL BBR NETWORK OF EXPERTS

Golden Strands50thAnniversary feature

Evolution of stay cable technologyand application across 400 projects

www.bbrnetwork.com Fourth Edition 2010

Win-wind situationGreen energy technology and expertise

Nuclear inspectionInspection and maintenance of

post-tensioning at Swedish power plants

High speed rail projectsBridge construction for Spain’s excitingnew high speed train network

In the public arenaInnovative and durable solutionsfor international stadium and arena projects


How continuing investment in people drivesquality and success within the BBR Network

Bruno ValsangiacomoChairmanBBRVT International Ltd

Marcel PoserCEOBBRVT International Ltd

EDITORIAL OFFICEBBRVT International LtdTechnical Headquarters and Business Development [email protected]

EDITOR Jane SandyCONTRIBUTING EDITORThomas RichliDESIGNER Caroline DonnerCONTRIBUTING DESIGNERSValentina Milhajlovic, Daniel SennPUBLISHER BBRVT International LtdNUMBER OF COPIES 11,000Printed in SwitzerlandEvery effort is made to ensure that the content of this edition is accurate butthe publisher accepts no responsibility for effects arising there from.© BBRVT International Ltd 2010

SOURCES AND REFERENCESBridges sectionTimely launch for rail viaduct: en.wikipedia.orgFlying over the fjord: en.wikipedia.org & www.roadtraffic-technology.comBuildings section Scientific solution: plato.stanford.edu Sustainable future:en.wikipedia.orgTanks & Silos section Nuclear inspection: www.vattenfall.seSpecial Applications sectionWin-wind situation: swedentravelnet.com &en.wikipedia.org & www.vindparkvanern.seMRR section Metamorphosis over Danube: www.wienerlinien.atStay Cables section Menn, C. 2000, As Simple As Possible, But Not Simpler.Challenges & Solutions. Finley Mc Nary. July/August Edition. Gimsing, N. J. 1997.Cable Supported Bridges: Concept and Design. 2nd ed.Chichester : JohnWiley and Sons. en.wikipedia.orgLandmark Structures section In the public arena: en.wikipedia.orgAesthetically enhanced view: www.bridgelab.ch Pioneering roof construction:9th IABSE Congress Report (Amsterdam, 1972), IABSE, www.iabse.org

Editorial, sources and references

2 CONNÆCT

Talking BBR4 Diversity & competitive edge

6 MAIN FEATURE:Excellence throughpeopleAn outline of BBR’s people-basedapproach to excellence in service

8 BBR Factory Production Control

8 BBR E-Trace Trading & QA Platform

10 Sharing global knowledge andexperience

11 Remembering our roots

Bridges

12 High speed rail projects, Spain

17 Gauteng Freeways ImprovementProject – Package E, South Africa

18 Tartu Bridge, Estonia

19 TOARC 1 & 2, A75-A9 Highway,France

20 Hardanger Bridge, Hardanger, Norway

22 Lexkesveer Bridge, Netherlands

23 Jamarat Bridge, Saudi Arabia

24 Despeñaperros viaducts, Spain

24 Bridges 993, M6 Motorway,Dunaujvaros, Hungary

26 Dubai Bypass Phase III-Al QudraBridges, Dubai

26 Bridges in Riga, Latvia

27 Al-Dair Bridge, Basrah Governate, Iraq

28 Motorway Intersection Bridge,Kolomoen, Norway

30 Friedetal Bridge, A38 Motorway,Germany

32 Talbrücke Eselbruch, Germany

32 Seredeng River Bridge, Sarawak,Malaysia

34 Freimann Viaduct, A9 Motorway,Bavaria, Germany

Buildings

35 Car park, Sylvia Park Shopping Centre,Auckland, New Zealand

38 Top Ryde Shopping Centre, Sydney,Australia

38 Royal Children’s Hospital, Melbourne,Australia

39 Printing house, Zagreb, Croatia

40 Copernicus Science Centre,Warsaw,Poland

42 St David’s Centre Car Park, Cardiff, UK

43 Qatar Airways 4-Star Hotel, Doha,Qatar

44 Ajman One – Phase 1, UAE

45 Integrated home, transport & retaildevelopments, Singapore

46 Magic Box Athletic Complex, Madrid,Spain

46 TDIC HQ,Abu Dhabi, United ArabEmirates

47 Claremont Quarter, Perth, Australia

48 Paddington Central, London, UK

Tanks & Silos

50 Aeration Tanks, EasternWaterTreatment Plant, Australia

53 Seventh & eighth LNG tanks,Barcelona, Spain

54 Tank & Silo Construction, United ArabEmirates

56 COVER FEATURE:Nuclear inspectionWe examine inspection andmaintenance of post-tensioning atSwedish power plants, focusing on theRinghals 2 nuclear installation andfeaturing the BBR Network’s bestpractice inspection techniques.

58 LNG tank, Stavanger, Norway

U2/6 Donaumarina Bridge,Vienna,AustriaThanks to the BBR Network, this bridge is nowfulfilling its third and final purpose – to serve aspart of Vienna’s underground railway network.

AerationTanks, EasternWaterTreatment Plant,AustraliaOur alternative design solution, involving cast insitu post-tensionedtank construction, produced significant project cost savings whilelowering leakage risk and long term maintenance issues.

Metamorphosis overDanube

Water industry innovation

Contents

3CONNÆCT

Stay Cables

59 COVER FEATURE:Golden strandsCelebrating 50 years of BBR stay cabletechnology – and 400 projects – an in-depth review of the evolution of staycable technology and application,combined with a commentary on state-of–the-art techniques and know-how –plus a review of stay cable structuresaround the world.

Special Applications

70 The Zagreb Arena, Croatia

74 Alan Macdiarmid Building,VictoriaUniversity,Wellington, New Zealand

76 Temple of God Providence,Warsaw,Poland

76 DY Patil Cricket Stadium, Nerul, NaviMumbai, Maharastra, India

78 Catagunya Dam Upgrade, CentralTasmania, Australia

80 Maliaño Bridge, Santander, Spain

81 Infrastructure protection works, DeadSea, Jordan

82 COVER FEATURE:Win-wind situationCreation of the Vänern Wind Farm inSweden’s largest lake required specialistBBR Network expertise. FeaturesTechnical Insight on wind farm ‘greenenergy’ construction technology.

84 Segmental pontoon, Lumut Port, Perak,Malaysia

84 People Mover Systems, Changi Airport,Singapore

85 BBRWIGAbloc, heavy lifting, Asia

MRR

86 U2/6 Donaumarina Bridge,Vienna,Austria

90 Factory roof strengthening, Pabianice,Poland

90 Bloomingdales Store, Dubai Mall,Dubai, United Arab Emirates

91 The Angel Building, London, UK

92 Grafton Bridge, Auckland New Zealand

94 Wharf upgrading, New Zealand

97 Wouri River Bridge, Douala, Cameroon

97 Seismic retrofitting of school, NewDelhi, India

98 Fire damage rectification, Dubai, UnitedArab Emirates

Landmark Structures

100 COVER FEATURE:In the public arenaOur Landmark Structures sectionfocuses on the innovative and durablesolutions for international stadium andarena projects in Australia, Germany andSingapore which continue to serve theirpurpose many years after theirconstruction.

110 BBR Worldwide Directory

Car park, Sylvia Park Shopping Centre,Auckland,New ZealandBBR post-tensioning has delivered huge benefits for thismajor shopping centre car park construction – improvingend-user experience and saving construction costs.

The BBR Network is applying BBRTechnology and best practice totwo schemes which are part ofSpain’s major high speed railwaynetwork development strategy –the Barbantiño Viaduct,Galicia and two newviaducts in Villena-Sax.

The Zagreb Arena, CroatiaA stunning new landmark project where BBR Technology hasachieved a tight deadline and contributed to a trulyambitious yet functional public structure.Increasing retail accessibility

Grand spectacle

70

COVER FEATURE:High speed rail projects

4 CONNÆCT

With 66 years at the leading

edge of construction

technology, the BBR

Network now extends to over 50

countries and, as the world’s leading

group for post-tensioning, stay cables

and related construction engineering,

has completed some of the most

challenging projects on the planet.

This does not happen by chance – BBR

VT International’s CEO, Marcel Poser

talks about the blend of technology,

culture and diversity which drives

their success, as well as business

performance over the last twelve

months.

WHY DOES THE BBR NETWORK‘WORK’?MP:Well, first you have to understand theSwiss culture – there are a lot of similaritiesbetween the BBR Network and the waythings work here.In Switzerland, we have the highest foreignpopulation in all of Europe and livedpeacefully and successfully together forcenturies.We have four national languages,plus English as a business language andadministratively, we are organized into‘cantons’ – or federal states – which, althoughgoverned centrally, have a great deal ofautonomy. In Switzerland, we have theworld’s oldest direct democracy – meaningthat it is always the people who have the lastword.The BBR Network functions similarly andour business approach is based on sharedunderstandings first, rather than theenforcement of centralistic rules. OK, yesthere are clear boundaries for people tomove within, as well as clear and ambitioustargets and a common understanding ofrules within this family … which rarely haveto be enforced.We have all the desire toprovide excellence in construction servicesand above market average quality to ourcustomers.We respect and value eachorganization’s individuality – it is what makesthem successful in their own market place.The Network members form alliances,collaborate and share resources as you mightdiscover in many articles in this year’s editionof CONNAECT.

WHAT IS THE ROLE OF BBR HEAD-QUARTERS WITHIN THE NETWORK?MP: Our role is to provide our Network withthe means to be the most successful –cutting edge technology, systems,methodology, business and processoptimizations.We centralize only what reallymakes sense without encroachingunnecessarily on the local businesses – trulythe Swiss approach. Items which are centrallyorganized obviously include R&D,procurement of key products, qualityassurance, education, training, performanceassessment, as well as technical andengineering consulting for challenging, uniqueand special projects.We are the ‘think-tank’ ofthe network – identifying and absorbing theknowledge available within the family.We are

also the main interface for new clients andinternational business relations.

HOW DO YOU ENSURE GOALS AREACHIEVED?MP: Mainly, we listen.We believe in andoperate a collective approach to product andstrategy development – something that wouldprobably drive an old-fashioned R&Dtraditionalist crazy. But it’s just no goodimposing new products or methodologywhen you don’t know exactly what people allaround the world actually want – as abusiness model, that just doesn’t work for us.Over the years, we’ve built our business andtechnology on shared visions.This comesabout by talking to people and understandingtheir challenges and needs.We try to react

Diversity&

5CONNÆCT

and provide things before they’re actuallyneeded – so we’re always looking ahead. Ofcourse, at the heart of this are customerrequirements – it’s logical that if we satisfy ourcustomers, we will have a successful business.We also take an active and leading role inindustry dialogues and committees and ourparticipation is aimed at introducing new andimproved technology and techniques.We arealways engaged in initiatives for improvingquality, performance, longevity and reducelifetime maintenance costs for the structuresinvolved.

HOW DO YOU MANAGE CONFLICTINGNEEDS?MP:The latest developments mean ourtechnology is now so very flexible that any

differences in market requirements can bemet by good construction design.Within acompetitive environment, you simply cannotafford to develop a product to fit onemarket alone – and resource sharing onlyworks if the same systems are used by all.Our universal BBR VT CONA CMX post-tensioning systems – which we starteddeveloping way before the European CE-marking regulations were applicable – arenow so easily adaptable to suit localconditions that most special needs can befulfilled without reengineering – and mostimportantly, without costly and timeconsuming project-specific testing.Take theCatagunya Dam – featured in this edition ofCONNAECT – where the base technology isour high capacity CMI system for nuclearapplications which, because of the extensivetesting beyond requirements alreadycompleted on the CMI system, also easilyfulfills the needs for these largest–in-the-world ground anchors.In short, sustainable development, havingsolutions for market trends before thesetrends are fashion, combined with ourNetwork members who are locally well-connected and have strong local roots andshare the common goal of delivering thehighest quality for our customers is oursecret for success.

HOW DO YOU MANAGE QUALITYWITHIN THE NETWORK?MP: As far as quality assurance is concerned,this is a massive area for us – ourreputation depends upon it.That’s why, in2009, we launched the BBR E-Trace systemwhich integrates delivery with qualitycontrol and unites it with sharedknowledge. So, if there’s a problemsomewhere, everyone can share thesolution and the international pool ofknowledge increases.Finding the right system was important forus – it had to be something which was easyto use and didn’t bend BBR Networkmembers out of shape. So, we opted for in-house development of a completely new,never seen before web-based solution,rather than imposing off-the-shelf businessmanagement software on everyone.The BBR Network members, as PTSpecialists, have the most vital role indelivering quality … the best technology ismeaningless if it is installed poorly.Professional execution is ensured by ourcertified PT Specialists, for whom weprovide training, assessment and support sothey remain at a high level.We have alsocontracted an independent auditor who not

only audits us, but also all our manu-facturing facilities as well as our Networkmembers.

GIVEN BBR E-TRACE, DO YOU ONLYRELY ON ELECTRONICCOMMUNICATION?MP: Even in this digital age, there’s nothingquite like personal contact to ensure thatunderstanding is achieved and maintained.Last year alone, we had many op-portunities to bring BBR Networkmembers together. As well as the AnnualConference, we’ve organized trainingseminars.We’ve also always supportedmembers locally – for instance, atmeetings with contractors and customers.E-tools are great and extremely helpful,but personal contact remains a vitalingredient – at the end of the day, theconstruction business is still a peoplebusiness and E-Trace, our products andconsulting work are only gears in theperfectly synchronized, precise BBRchronograph … well, a Swiss-made BBRchronograph to be absolutely precise!

WHAT’S BUSINESS BEEN LIKE OVERTHE LAST YEAR?MP: Actually, it’s been rather good – despitethe global financial crisis. In 2009, the totalannual BBR group turnover reached overCHF 300 million in post-tensioning, staycable and related construction engineering –this revenue would be even more thandoubled if all group activities were to beincluded.While in some regions it’s been atougher year than usual, generally BBRNetwork members have been enjoying agood, steady flow of interesting work – asyou’ll see from the pages which follow. More-and-more diverse projects are appearing inour magazine which reflect the wide diversityof the BBR Network and its customers.Looking ahead, there are again some excitingprojects in view including the Sava Bridge inBelgrade, Serbia which – with its 376 m longmain span – will be the second longestcable-stayed bridge in Europe, the BasarabBridge in Romania,Vidin Calavat in Bulgaria,more record dams in Australia, nuclear worksin Scandinavia and many more projectswhich are at too early a stage for me to beable to reveal too much right now.In terms of products, we are diversifying ourportfolio beyond post-tensioning and staycables, such as the measurement equipmentalready introduced and the newly–launched,brand new CE-marked BBRVT pot bearingswe will continue to push for new frontiersand more innovation. �

compe

titive

edge

TALKINGBBR

6 CONNÆCT

A significant portion of the turnover of theBBR group goes into service, where acarefully considered supply chain process andwell-trained, experienced staff are of vitalimportance in delivering the highestinstallation standards for our clients.

HIGHEST CUSTOMER SERVICESTANDARDSOur PT Specialists are qualified and certifiedto assemble and install European approvedand CE marked BBRVT CONA CMX PTkits.They are responsible for compliance withall regulations set out in the relevantEuropean Technical Approvals (ETAs) for ourPT kits, for complying with the respectivestandards and regulations in force at theplace of use, for ensuring a professionalexecution of PT works and for endorsing allsafety-at-work and health protectionregulations.BBR Network members have a long historyin design and installation of PT, as well asrelated construction fields.They are underthe continuous supervision of BBRVTInternational – the ETA Holder – and areexperts in all post-tensioning tasks, such as:� Logistics and supply of a complete PT kitto the construction site

� Full assembly and installation service on site� Quality assurance.

The BBR Network pursues the ambitious goal of providing notonly the finest approved Swiss technology, but also the bestservice and installation capabilities to their customers

around the globe. This goal is being met through the use of qualityassurance tools – such FPC and BBR E-Trace – combined with aconsiderable investment in people to ensure the highest level ofcustomer service. Thomas Richli, Business Development Managerat BBR Headquarters provides this report.


7CONNÆCT

Although each of our PT Specialists havedifferent organizational structures suited tobest serving their local markets, they allmaintain the following key departments:� Technical� Logistics� Site operationTogether, this team takes professionalresponsibility for the project from design tocompletion, dealing with and reporting ontechnical, logistical, safety and best practiceissues along the way.

BBR PT SPECIALISTS – CAREFULLYSELECTED AND ASSESSEDAll our BBR PT Specialists go through aseries of application, qualification andcertification procedures before they arefinally certified by the ETA Holder. After acomplete and successful certification process– conducted by experts from BBRHeadquarters, or from an externalcertification body – we issue an official BBRPT Specialist certificate which can be viewedand downloaded from our BBR Networkwebsite www.bbrnetwork.com.Our certification process has four activephases:� Application from a potential BBRNetwork member to be certified for BBRPT works in a particular territory

� Preliminary evaluation and assessment� Issue of a certificate� Continuous re-evaluation and renewal ofthe certification.

During the process, we verify all referencesand carry out ‘reality checks’ locally to satisfyourselves that the organisation and its staffmeet the BBR criteria for experience,capability and best practice.

All our PT Specialists are audited and re-evaluated every 12 months after the firstissue of a certificate. Re-evaluation includesall elements of the preliminary evaluation aswell as further assessments.

CONTINUOUS TRAININGPROGRAMMEDWe continuously educate our PT Specialistsin post-tensioning and stay cable products –in respect of systems, quality assuranceprocedures and installation of systems. Inorder to keep our members up to date, weorganize regular practical and theoreticaltraining courses in various regions of theworld for technical, logistics and site staff. Allour training sessions are concluded with anexam and fully documented. Sometimes,training sessions are also witnessed byindependent institutions and/or authorities.After the training courses, attendees areresponsible for cascading the knowledge to

their company personnel by arranging localinternal training sessions. In addition totraining required by us as an ETA Holder, wemake local training visits to the PT Specialist’slocation – such as for introductions to CMXsystems or logistics procedures.In 2009, five international training sessionswere held.We organized two logisticscourses where BBR PT Specialists weresuccessfully trained on our new trading andquality assurance platform BBR E-Trace.Twostay cable seminars were also held in Zurichand Singapore where we also introduced ournewly developed strand stay cable system,BBR HiAm CONA. In Paris, at our annualGlobal BBR Conference, commercial andtechnical presentations were given includingproject reports from around the world.A culture of continuous education within theBBR Network ensures a high qualityexecution of post-tensioning work for ourcustomers. �

TALKINGBBR

8 CONNÆCT

Traceability is the process of recordinginformation relating to the changes made atevery point in the life of a component –starting from the raw material throughproduction, storage, supply to the PTSpecialist, storage in stock, supply, storageand installation on site. Our goal is the‘cradle-to-grave’ collection of componentdata.Data is exchanged between parties involvedby way of contractual documents such asorders, drawings, operating and processingforms and procedural documents. Mostrecently, our FPC process has been

incorporated into our new trading platform– BBR E-Trace.Compliance with the complete FactoryProduction Control system is audited by anindependent approved or ‘notified’ body –MPA NRW – and any non-conformity mustbe rectified prior to the CE marking. Inaddition to our continuous audits and testingof the production – the approved bodycontinues to exert full control during thevalidity period of our ETA.These provisions guarantee proper qualityand compliance of the kit componentsdelivered to site.

Independently Assured Quality

Stefan Lipkowski of independent testing,monitoring and certification body, the

Materialprüfungsamt Nordrhein-Westfalen(MPA NRW), describes his organization’swork with the BBR Network.As a ‘notified body’ for matters concerningEuropean Construction Products Directive89/106/EEC (CPD), we have been workingtogether with BBRVT International on thebasis of a certification and monitoringcontract since 2006.We are responsible for the initial type-testing of the European-approved BBRVTCONA CMX post-tensioning systems, theinitial inspection of factories and FactoryProduction Control (FPC), the certificationof the product, the continuous surveillance,assessment and approval of FactoryProduction Control and the audit testing ofsamples.Our certification procedure determineswhether consistent development of theinternal quality management system andexemplary implementation of the FactoryProduction Control by BBRVTInternational – a multiple ETA holder –fulfills the given requirements.This process-driven approach ensures thatBBRVT International can draw on many

excellent references over a comparativelyshort period.To maintain effective andefficient operation of processes, BBR hasimplemented a stringent qualifyingprocedure for manufacturers and users.Supported by the adoption of an internet-based tool (BBR E-Trace), the interactionbetween all parties concerned and thetraceability of required documents havebeen crucially improved. An additionaladvantage of this innovative procedure isthe continuous monitoring of the internalquality management system by BBRVTInternational and by MPA NRW forinspection at any time.Our objective is to develop the relationshipand co-operation with BBRVTInternational, as part of an internationalnetwork with the common goal ofpermanent improvement of performanceto ensure a high level of quality forapproved post-tensioning systems.

Four years ago, we implemented the BBR Factory ProductionControl (FPC) system which provides highest productquality standards – and full component traceability, the most

direct way of ensuring quality.

BBR FACTORY PRODUCTION CONTROL

Highest quality standardsand full traceability

BBR E-TRACE

Trading &QA Platform

BBR E-Trace – our in-house developedinternet-based software

– links all members of theGlobal BBR Networkincluding BBR PT Specialists,BBR ComponentManufacturers (CMs) andETA Holder, BBR VTInternational. Thiscomprehensive e-commerceplatform leads users throughthe quality process, ensuringthat each step is documentedand recorded.

The platform facilitates the everyday workof all BBR Network members and alsosupports effective supply chainmanagement.

9CONNÆCT

ENGINEERING DATABASEThe platform includes a powerful andcontinuously updated engineering databaseof all our systems including CMX, where allsystem and part details, drawings,specifications, quality checks are available forall CM and PT Specialist users.

PROCUREMENT AND ORDERFULFILLMENTPT Specialist users can procure BBR com-ponents (parts) from our selected CMs.Theusers can check and compare supply scenariosand corresponding delivery times and thenthey can either directly place an order ormake an inquiry online with one of our CMs.

STOCK MANAGEMENTIn BBR E-Trace, we are able to view thestock, at any time, including all individualQuality Certificates of all our CMs, after theyhave produced the BBR parts to ourspecifications and stored them.Once an order is confirmed, the CMallocates the respective parts before the PTSpecialist receives, checks and stores thecomponents.The results of the incominginspection are documented.

INSTALLATIONThe installation process starts with opening aconstruction site in BBR E-Trace before partscan be delivered to a site with a DeliveryNote (DN). Once all components areinstalled on site, an Installation Report (IR)respective Definite CE marking is issued andcan be handed to the client upon request.The construction site database enables thegeneration of individual project referencesheets or lists.

USER MANAGEMENTThe following trained users within PT Spe-cialists and CM organisations are involved:� Procurement and order fulfillmentmanager

� Quality manager� Logistics and stock manager� Technical manager� Site and construction manager

COMMUNICATIONBBR E-Trace provides a complete onlinedatabase of all PT Specialists and CMs andtheir users including contact details, plus aseries of shared tools to facilitate efficientcommunication and swift decision-making.Latest changes and enhancements arecommunicated through the front pagenews facility.

QUALITY MANAGEMENT ANDDOCUMENT CONTROLThe platform leads the user through thequality process required. Each step isdocumented and recorded in theplatform and can be tracked and viewedwhenever needed.The platform enablesuploading, storing, tracking, viewing anddownloading documents online.

TRACEABILITYTraceability is one of BBR E-Trace’sprimary strengths.The built-in trackingsystem provides the facility to track,identify and instantly trace all parts, nomatter what their current status – everysingle part can be detected at any time.

�

TALKINGBBR

USER MANAGEMENT

BBR E-TRACE MODULES

ENGINEERING DATABASE

PROCUREMENT & STOCK INSTALLATIONORDER FULFILLMENT MANAGEMENT

DN

IR

The prestigious BBR Project of the Year Award 2009 was presented to BBRConstruction Systems (Malaysia) in recognition of their work on the Kampong

Pandan Flyover in Kuala Lumpur.The highly complex 12-span, 568 m long highway flyoverscheme was designed based on balanced cantilever construction using form travelers. BBRCONA tendons were installed for the spans and cantilever to build the structure in anefficient and timely manner without any interruptions to busy traffic flows.

Kampong Pandan Flyover, Kuala Lumpur

BBR PROJECT OF THE YEAR 2009

10 CONNÆCT

Once a year, the Global BBRConference is held withdelegates coming from all

over the world.We share knowledgeand experiences while learning moreabout the BBR Network’s latestprogress and plans. In addition,several social events, such as the BBRGala Dinner and the BBR CharityGolf Tournament take place.

PARIS ‘09In 2009, again, the Global BBR Conferenceproved to be a huge success with over 50delegates converging on Paris.The conference was launched with anevening cruise along the River Seine duringwhich the assembled delegates joined tocongratulate the winners of the BBR Projectof the Year 2009 and the newly launched2009 CONNAECT Awards – the perfectstart to the Global BBR Conference!

PROGRESS, PRODUCTS ANDQUALITYThe main conference program began with anintroduction by Marcel Poser who gave

details of past, current and upcomingactivities of the international BBR Networkas well as the completely newly developedBBRVT CONA CMX family.The next presentation was run by PiotrKrawczonek who emphasized the vital roleplayed by quality management within theBBR Network. After Thomas Richli’s sessionon steel price fluctuations, he was joined byPiotr for the first real-time demonstration ofthe new BBR E-Trace system which went liveduring summer 2009.

STAY CABLE STRUCTURES –UNIQUE BBR EXPERIENCEMarcel Poser opened the comprehensivestay cable seminar and was followed byAntonio Caballero who presented a detailedtechnical evaluation.To be certain that delegates clearlyunderstood this complex topic, a 30-question ‘exam’ was held at the end of thesession. Congratulations go to delegates fortheir ability to absorb such information sobrilliantly!

Sharing global knowledgeAND EXPERIENCE

11CONNÆCT

Remembering our roots

Frau Irma Birkenmaier,now aged 92 years,was married to BBR-founder MaxBirkenmaier for some sixty years and has agreed to share some reflections and fondmemories about the early days of the company.Even today,she continues to take great

pride in the pioneering achievements of those early days and to enjoy relationships createdduring business trips all over the world.BBR was first formed, in 1944, when three technically brilliant young engineers – allgraduates of ETH, the Swiss Federal Institute of Technology in Zurich – started apartnership known by their initials – BBR – Max Birkenmaier, Antonio Brandestini andMirko Ros.Both Max Birkenmaier and Antonio Brandestini had been working with a specialistgeotechnical firm, Swissboring, while Mirko Ros was at EMPA, the Swiss FederalLaboratory for Materials Testing and Research.AsWW2 drew to a close, it was clearthat ingenious construction technology solutions would be required to offset thematerials shortages, particularly cement and steel.Frau Birkenmaier describes Max as very much an engineer and technically brilliant –although he was a rather academic, conservative type, while Antonio was more of anoutgoing entrepreneurial character, a businessman. Meanwhile, Mirko Ros’ family hadacademic roots, his father being a professor at ETH. Basically, they formed a very goodteam.In the early days, Frau Birkenmaier supported the young entrepreneurs as a clerk intheir offices on Zurich’s Limmatquai and Max used to take his son, Max junior, onconstruction site visits. A certain family atmosphere developed within the business, asboth Max and Antonio used to maintain contact with their employees. Clearly, this wasencouraged by Antonio who invited business partners, professors and BBR Networkmembers to his home.She recollects that in 1958, Max’s expertise was applied to a more personal project –securing the family home that they were building, on sloping ground, with post-tensioned anchors. Apparently, Max had many ideas which went beyond pure post-tensioning – for example, he investigated how PT could be used to store energy ...stress – store – and finally relieve. During his career, he was heavily involved in normcommittees and received a honorary doctorate from ETH for his achievements.The dedication and work of our pioneering founders acts as inspiration and a guidinglight as we continue, today, to develop construction technology to meet the demandsof the future. �

TALKINGBBR

BBR Polska site engineer, Bartosz Lukijaniuk, and hiswife enjoy a 3-day trip to Switzerland – the prizefor producing the Best Engineering Report 2009, acomprehensive technical report on constructionaspects of the striking new sports arena in Lodz.

PEOPLE, PLACES AND PROJECTSBBR Network members formally shared details oftheir recent work and led discussions aboutparticular technical aspects of their projects.Presentations included:� Sports Arena Łódz – Bartosz Łukijaniuk, BBRPolska (Poland)

� Seismic strengthening of Kawarua River Bridge– Paul Wymer, BBR Contech (New Zealand)

� Ormiston Road Bridge – Paul Wymer, BBRContech (New Zealand)

� South Hook LNGTerminal, SouthWales – BobFreedman, Structural Systems (UK) Limited

INTERNATIONAL INSPIRATIONThe meeting was closed with an inspiringworkshop where several international groupsdealt with specific commercial and technicaltopics affecting the BBR Network.

BON APPETIT – ET AU REVOIR!Le First Restaurant, opposite the Jardins desTuileries, was the venue chosen for staging theBBR Gala Dinner. Finally, the event had reached itsend ... and a new clock started to run thecountdown toWashington 2010.

WASHINGTON 2010We are holding our conference this year tocoincide with the International fib Congress andExhibition – which is held only once every fouryears.The fib’s theme is particularly appropriateto BBR – “Think globally … build locally” – it’swhat we’ve been doing for years! �

12 CONNÆCT

Timelylaunchfor rail viaduct

Aland of stunning natural beauty, Galicia, in thenorthwest of the Iberian Peninsula, is alsofamous for its gastronomy and as the home of

the legendary ‘Camino de Santiago’. Each year, tensof thousands of Christian pilgrims and other travelersflock to Santiago de Compostela – on foot, bicycle orhorseback.Nearby, is the Barbantiño Viaduct that will carry theAVE high speed railway from Madrid to Santiago.Gustavo Delgado Martín, from BBR PTE in Spain,describes the innovative solution for constructingconcrete viaducts using the incremental launchingmethod on a downward gradient. �

Barbantiño Viaduct, Galicia, Spain

13CONNÆCT

BRIDGES

14 CONNÆCT

The final design for the BarbantiñoViaduct was a single box concretegirder.The incrementally launchedconstruction method was chosenbecause of the rough terrain andgreat height of the piers.

The viaduct is 1,176 m long, with 18 spans (52 m+ 16 x 67 m + 52 m).The plan layout is a curvewith a 7,250 m radius and the elevation starts at2.21% and ends with a 1.09% descending slope.

DOWNHILL LAUNCHINGLaunching was executed downhill from the topabutment – the total weight to be launcheddownwards in the last phase was 43,000 t.Themaximum height of the viaduct above the valleyfloor is 98 m.The superstructure was built basedon a weekly cycle and the standard section lengthwas 33.5 m.On the top of each pier, a guiding system wasinstalled which consisted of two steel structurespositioned on both sides of the deck whichhelped to guide the structure during the launching.The viaduct was launched with three pulling jacks

and three retaining jacks.The pulling and retainingjacks each have a capacity of 5,000 kN, with42 compacted steel strands and the stroke of eachjack is 400 mm.With this capacity of stroke, wereached launching speeds of six meters per hour.All jacks were synchronized.A retaining force wasset and, once the pulling force was bigger than theretaining one, the viaduct started to move.Themovement of the pulling jacks was synchronized indisplacement, using the total pulling and retainingforce as the control parameter.

CLAMPINGFor the execution of each segment, we used aclamping system composed of 12 jacks, each witha braking capacity of 250 t, providing a totalbraking force of 3,000 t – which ensured theviaduct did not move between two consecutivelaunchings.In addition, this clamping system was activatedeach time that an alarm became active during thelaunching process.This meant that the launchingwas stopped and the viaduct was clamped by the12 transversal jacks.

TEAM &TECHNOLOGY

OWNERAdministrador de InfraestructurasFerroviarias (ADIF), Spain

MAIN CONTRACTOR Ave MasideUTE (FCC + COMSA), Spain

DESIGNER FCC ConstrucciónTechnical Services & EIPSA, Spain

TECHNOLOGYBBRVT CONA CMI internalLaunchingBar

BBR NETWORK MEMBERBBR Pretensados y Técnicas Especiales,S. L. (Spain)

15CONNÆCT

EQUIPMENTAll the equipment involved in the launching wasinstrumented and controlled by a PLC –pressure transducers for measuring the pulling,retaining and braking forces, anemometer formeasuring the wind speed, clinometers at thepierhead, encoder and laser for measuring thelaunching speed and stroke sensors. Meanwhile,all measuring instruments in the pierscommunicated with the main control unit via awireless connection.

POST-TENSIONING SYSTEMThe viaduct has 907 t of post-tensioning –comprising 497 t of launching post-tensioningand 410 t of service post-tensioning completedafter the final launching.The system used wasBBR VT CONA CMI 1906 and 2406 anchoragesand couplers.This method of construction ensured theproject was realized on time – the main bridgestructure was completed within nine months. �

BRIDGES

Alta Velocidad Española (AVE) is a high speed railway service, with trainsoperating at speeds of up to 300 km/h on dedicated track in Spain. Thename translates literally into English as ‘Spanish High Speed’ – but theacronym is also a play on the Spanish word ‘ave’, meaning ‘bird’. All AVEtrains are currently operated by RENFE, the Spanish state railway company.The Spanish government has an ambitious long-term plan to make 7,000 kmof high-speed railway operational by 2010 – with all provincial capitalsbeing, at most, only four hours from Madrid, and six-and-a-half hours fromBarcelona.According to the Strategic Plan for Infrastructure and Transport (PEIT)developed by the Spanish Ministerio de Fomento (Ministry of PublicWorks), a second expansion program is planned to start in 2010-11, whenthe last lines of the first program currently under construction beginoperation. This plan has a ten-year scope and its aim is to extend the 300km/h network to 10,000 km by the end of 2020. This would be the mostextensive network in Europe, with several operational links with France andPortugal – and is by far the most ambitious high speed rail plan currentlyunderway within the European Union.

Local insight:Spain’s high speed trains

“LAUNCHING WAS EXECUTEDDOWNHILL FROM THE TOPABUTMENT – THE TOTALWEIGHT TO BE LAUNCHEDDOWNWARDS IN THE LASTPHASE WAS 43,000 T.”

16 CONNÆCT

The success of Spain’s new highspeed railway infrastructure isensured, says José Luis Plaza

Bacete of BBR PTE as it will provide areal alternative to traveling by car –thus reducing congestion at the easternexit of Madrid, the A3 motorway, wherethere are always traffic jams.

Part of this enormous project is theconstruction of two new viaducts on theapproach, from Madrid, to ComunidadValenciana – Viaducto de la Acequia del Rey andViaducto de Cordel de Sax. BBR PTE is involvedin the construction of these two viaducts. Ourwork consists of the supply, installation, stressingand grouting of all the longitudinal tendons.

DESIGN HIGHLIGHTSThe design has been developed by the technicalservices department of FCC Construcción.TheBBRVT CONA CMI multistrand system is beingused for the post-tensioning, in accordance withthe European Technical Approval ETA-06/0147.The cross-section is the same for both viaductsand consists of a section of lightened concreteslab with five webs.The slab is 14 m wide,including the lateral cornices, and is 2.10 m highalong the whole deck.The technology used is BBRVT CONA CMI 2106 and 2406 for bothviaducts.The work is being executed concurrentlyby two separate project teams.

VIADUCTO ACEQUIA DEL REYThis concrete lightened slab viaduct has an overalllength of 1,394 m between abutments and has 44

TEAM &TECHNOLOGY

OWNER Administrador deInfraestruturas Ferroviarias (ADIF)

MAIN CONTRACTORFCC Construcción, S.A.

DESIGNERFCC Construcción Technical Services

TECHNOLOGYBBRVT CONA CMI internalAdvanced shoring

BBR NETWORK MEMBERBBR Pretensados y Técnicas Especiales,S. L. (Spain)

Span-by-span concrete decks

VIADUCTS INVILLENA-SAX, SPAIN

17CONNÆCT

spans, 25 m + (42 x 32 m) + 25 m.Theviaduct is being constructed using con-ventional formwork.The first span completedwas in the middle of the viaduct. Once thisspan was concreted, stressed and grouted,two sets of formwork were installed eitherside of the centre span.The same operationis being repeated span-by-span until the deckarrives at both abutments. One work teamexecutes all the works, changing from onespan to the opposite, achieving completecycles of one span per week.Acequia del Rey has approximately 360 t ofpost-tensioning steel. All the longitudinaltendons consist of 15.7 mm diameter strandand the multistrand system chosen is the BBRVT CONA CMI 2106 and 2406 fixed typeK couplers, used at the end of each phase inthe construction joint. A 750 t hydraulic jackis being used to stress the tendons.

VIADUCTO CORDEL DE SAXThis viaduct consists of a concrete lightenedslab deck, similar to Acequia del Rey. It has anoverall length of 1,458 m between abutments,with 46 spans, 25 m + (44 x 32 m) + 25 m.However, the construction method is different– a moveable scaffolding system for full spancast-in-situ is being used. It is moved forwardover piers, span-by-span, until it arrives at theopposite abutment.The casting cycle has beenoptimized into a stable week-by-week rhythm.Cordel de Sax has approximately 385 t of PTsteel. All the longitudinal tendons consist of15.7 mm diameter strand and the multistrandsystem chosen is the BBRVT CONA CMI2106 and 2406 fixed type K couplers.

KEY BENEFITS & ADVANTAGESOne of the infrastructure owner’s mainrequirements was rapid construction. Use ofthe BBR system enabled the post-tensioningto be carried out at a low concrete strength– achieving significant time savings.In addition, the repetition of identical tasks ineach span favors rapid construction andhelps to reduce direct and indirect costs.The program envisages that all post-tensioningwork for both viaducts will be finished in lessthan 12 months.The new AVE route toValencia – Murcia is expected open forpassenger service during 2012 and we will beproud to have contributed BBR know-howand technology to this exciting project. �

A major drive was initiated by the SouthAfrican National Roads Agency Ltd(SANRAL) in 2006 to upgrade the highwaynetwork in the Gauteng Province of SouthAfrica, with the majority of upgrades in theJohannesburg and Pretoria areas.This major upgrade project was tenderedin different packages. Package E was wonby the Siyavaya Highway JV – a jointventure between Group 5 CivilEngineering, one of the top three civilengineering contractors in South Africa,and various smaller civil engineeringcontractors.Package E contains three incrementallylaunched bridges on the N12/N17highway intersection and at the N3/N12Elands interchange in Johannesburg, SouthAfrica and Structural Systems (Africa) hasbeen contracted for:�Design of cast beds and temporarypiers, design and supply of temporarybearings, design of modifications toabutments to suit launching equipment,design and supply of launch girdersincluding connection to bridge deck.

� Supply and site operation ofincremental launching equipment andbraking system.

� Supply of BBRVT CONA CMI anchors,strand, galvanized ducting for post-tensioning.

� Site installation, stressing and grouting ofall post-tensioning.

Two of the bridges are straight andconstructed on either side of an existingbridge.They are 150 m long and on anaverage downhill slope of 4%.We deviseda brake system to restrain the bridgeduring launching using two 400 t brakejacks connected to the bridge deck with40 mm stress bars, as well as a series ofbrake pins for parking the bridge betweenlaunches.The third bridge is a horizontallyand vertically curved bridge with a totallength of approximately 400 m.The introduction of BBRTechnology byStructural Systems into South Africa hasbeen widely welcomed by designers andcontractors throughout the region.Welook forward to many more challengingprojects here in the future! �

BRIDGES

Paul Heymans from BBR Network member StructuralSystems (Africa) talks about their contract for threeincrementally launched bridges which form part of a

major freeway upgrade project in-and-around Johannesburg,South Africa. This is the first major contract secured by theStructural Systems Group – and first use of BBR VT CONA CMImulti-strand technology – on the African Continent.

GAUTENG FREEWAYS IMPROVEMENT PROJECT – PACKAGE E,JOHANNESBURG, SOUTH AFRICA

Launching in Africa

TEAM &TECHNOLOGY

OWNER South African National RoadsAgency Ltd (SANRAL)

MAIN CONTRACTORSiyavaya Highway Joint Venture

DESIGNERUWP / Nyeleti Consulting Joint Venture

TECHNOLOGYBBRVT CONA CMI internalLaunching

BBR NETWORK MEMBERStructural Systems (Africa)

18 CONNÆCT

This bridge is a very good example of howthe use of stay cables can add much to thearchitectural appearance of a structure andmake it just perfect. Although the bridge isnot huge – with a span length of only some70 m – it attracts the viewer, inviting closerinspection and discovery of every detail, aswell as enjoyment of how well the designfits the environment.

BRIDGE DECKThe bridge deck is of concrete, post-tensioned longitudinally, with post-tensionedtransversal beams which carry the deck withthe help of stay cables.The ends of thebeams exceed the deck in a transversaldirection, thus accommodating the stay cable

anchorages. In doing so, they allow thevisitor to observe the flow of forces fromone load bearing element to the other.

STAY CABLESWith an upwards glance, the viewerdiscovers where the cables penetrate thearch, as they are anchored on the inside.Thepipes and joints are all neatly crafted.Floodlights are installed on the underside ofthe arch, illuminating the bridge which hasbecome a city centre architectural attraction.Each of the four cables is made up of73 0.6” diameter prestressing strands whichare galvanized, waxed and PE-sheathed.Weused VT stays which were designed to beinstalled into the particularly small recess

pipes of the steel arch. As usual for thesystem – and in line with the demand foreasy and quick erection – the cables wereentirely preassembled on the bridge deck.

STRESSINGStressing was completed with fourmultistrand jacks – one at each of thedeckside anchorages. In this way, the cableforces required by the design could beintroduced very precisely and withoutvariances from one cable to another.Thewhole cable installation – from set up of thespecial equipment, production and erectionof the cables, through to completion ofstressing – took only four weeks.The opening of the new bridge was officially

Günter Damoser from BBR Network member VORSPANN-TECHNIKreports on an arch-shaped cable-stayed bridge in the Baltic.

Elegantlydefined

TARTU BRIDGE, ESTONIA

19CONNÆCT

celebrated with a big party shortly after itscompletion in summer 2009. Since then, ofcourse, the bridge serves to guide vehiclesand pedestrians over the River Emajögiand, at the same time, takes its place as anew landmark in the city of Tartu – withevery right to do so! �

BRIDGES

TEAM &TECHNOLOGY

OWNER City of Tartu, Estonia

MAIN CONTRACTOR Tilts, Estonia

DESIGNER Transmost

TECHNOLOGY VT stay cable

BBR NETWORK MEMBERVORSPANN-TECHNIK GmbH & Co. KG (Austria)

This new highway, in the south of France,has been constructed to make theconnection between the southern part ofthe A75 and the A9. It is an importantroute, explains Claude Néant from BBRNetwork member ETIC, because it formspart of the Pan-European E15 highway.All of the bridges for this new highwayare comprised of thin concrete slabswhich we post-tensioned with BBRVTCONA CMI after concreting.There aresix bridges on this section, all were post-tensioned – we used a total of 120 t ofsteel in the six slabs.Three of the bridges were incrementallylaunched using a centric BBRVT CONACMI tendon, BBR jack and a nose beam.We also supplied and installed elastomericbearings and expansion joints.The three identical bridges to be launchedwere each 48 m long, with two 24 m spansand had 1.06 m thick slabs – each bridgeweighed 1600 t.They were built and post-tensioned from one abutment andpushed, during the night, over the existing

highway.The pushing operation was carriedout by installing the nose beam and, belowthe slab, one centric BBRVT CONA CMItendon – one end connected to a steelpulley, fixed on the abutment at the front ofthe slab and the other, to a special steelplate, fixed to the back of the slab.Two special BBR 19T15 jacks wereassembled and connected directly to onespecial pump. Using this method allowed usto increase the capacity of movement andreduce the total duration of the launch.�

TOARC 1 & 2, A75-A9 HIGHWAY, FRANCE

THE FRENCH CONNECTION

TEAM &TECHNOLOGY

OWNERASF (Autoroutes du Sud de la France)

MAIN CONTRACTOR JV RAZEL – BEC

CONSULTANTSETEC International / Scetauroute / EGIS

DESIGNER RAZEL T&M – Saclay (91)

TECHNOLOGY BBRVT CONA CMI internalLaunchingHeavy liftingBearingExpansion joint

BBR NETWORK MEMBER ETIC S.A. (France)

20 CONNÆCT

A ferry-free connection will improve longdistance travel, as well as local journeys in theinner Hardanger area and getting to-and-fromOdda and Voss – between Bergen and Hardanger– and travel towards the upper part of Hallingdalwill also be made easier.

FUNDING & APPROVALThe €270 million Hardanger Bridge constructionproject will be partly financed by toll charges, localand regional contributions and savings on currentgovernment subsidies for funding ferry services.Approval for the bridge was given at the end ofFebruary 2006 by the Norwegian Government.While construction of the approach road began inMarch 2007, bridge construction started in May2009.

BRIDGE OUTLINEThe bridge will carry two lanes of traffic and havea separate pedestrian and cycle-way.The towersare approximately 200 m high and the side spansare 20 m and 45 m on the north and south sideof the bridge respectively.The relatively small difference between thebridge’s length and span is because the towersmust stand near the shore – the steep mountainwalls either side of the fjord mean that the fjorditself quickly becomes very deep.The maximumwater depth near the bridge is about 500 m andthe mountains surrounding the fjord are about1200 m high. Beneath the bridge, the clearancefor maritime traffic will be 300 m wide and55 m high.

Hardanger Bridge –which is set to bethe world’s most

breath-taking bridge project– is now under constructionamid the dramatic sceneryof the Norwegian fjords. It isa 1,375 m long suspensionbridge – 30 m longer thanSan Francisco’s Golden GateBridge – with a main span of1,310 m.When completed,explains Stig Solbjør ofSpennteknikk, the BBRNetwork Member inNorway, the bridge willreplace the ferry connection– across the world-famousHardangerfjord.

The main span is designed as a closed steel boxbeam and the bridge will be connected to eachend with a rock anchor system, developed bySpennteknikk.

INFRASTRUCTURE CONNECTIONSThe project also comprises a 2.4 km tunnel and0.8 km of road between the tunnel and thebridge. In addition, a 0.9 km footpath and a cyclepath will be built towards the bridge. At thenorthern end, the approach road will start at aroundabout inside the existing Vallavik tunnel.Thisroundabout will divide the traffic betweenGranvin, Ulvik and the new Hardanger Bridge.The southern side of the bridge will connect to a1,200 m-long tunnel that ends in a three-wayroundabout.The approach road will be 7.5 mwide and the speed limit will be set at 80 km/h.The toll collection plaza will be at the southernend of the bridge.The bridge is scheduled to open in 2013, atwhich point it has been estimated that the dailytraffic volume will be 2,000 cars.

TECHNICAL DESCRIPTIONThe suspension cables will be anchored by 76 BBRVT CONA CMI 2506 tendons installed on eachside.The cables will be placed in individually drilledholes from the upper anchor zone down to atunnel and anchored with anchors.The pylons will be anchored to the rock by a totalof of 32 BBR CONA 1206 rock anchors – with anaverage length of 21 m and with a anchoringlength of approximately six meters.

Flying over ...

HARDANGER BRIDGE, NORWAY

21CONNÆCT

The two pylons on each side will be connectedby three prestressed box girders, the latterfeaturing 78 BBRVT CONA CMI 1506 tendons.The access viaduct will be constructed as atraditional prestressed triple box girder with alength of 45 m and, here, the BBRVT CONACMI 1906 post-tensioning system will be used.�

BRIDGES

... the fjord

TEAM &TECHNOLOGY

OWNER Statens Vegvesen

MAIN CONTRACTOR Veidekke Entreprenør AS

CONSULTANT Statens Vegvesen, Norconsult AS andRambøll AS

TECHNOLOGY BBRVT CONA CMI internal

BBR CONA rock anchor

BBRVTTOBE pot bearing

BBR NETWORK MEMBERKB Spennteknikk AS (Norway)

With a length of 179 km, the Hardangerfjord is the third longest fjord in theworld and the second longest in Norway. The creation of the fjord beganabout 10,000 years ago when the Scandinavian land mass started to rise upas glacial ice started to melt. The lower parts of the valleys became floodedand so created the Hardangerfjord. The valley was originally not only madethrough glacial erosion, but also by the high pressure of melt water pushingits way beneath the ice.Human history of the fjord reaches back, far beyond Viking history, to thetime of hunters on the surrounding mountains and, later, farming along thisfertile area now considered to be the fruit orchard of Norway. The fjord hasgood conditions for fish farming. In 2002, fish farms were producing morethan 40,000 t of salmon and rainbow trout annually – making theHardangerfjord one of four major fish farming regions of the world.The fjord’s history as a tourist destination began in 1875 when travelentrepreneur Thomas Cook started weekly cruise departures from London toHardangerfjord.Today, the fjord is divided among 13 municipalities coveringsome 8,471 km² of land – but inhabitants only number a little more than 70,000.

Local insight:Hardangerfjord

22 CONNÆCT

The ferry of Lexkesveer, near the old city ofWageningen, is firmly established – there arehistorical accounts of the ferry dating back to the15th century. It was one of several ferries whichcrossed the Rhine, giving access between theNorth and South of the Netherlands. For morethan 500 years, there has been a dam betweenthe southern winter dike and the ferrystop, at thesummer dike.To improve transportation and provide extrastorage of water, the dam – which was in a goodshape – had to be replaced by a bridge as thewinterbed was deepened. At the same time newnatural habitats – wetlands – have been developed.

LEGO CONSTRUCTIONIt was appropriate that water should also haveplayed a major role in the design andconstruction methodology for this new bridge. Asthe building site only had a very short periodwithout water ingress, a construction method waschosen which allowed the bridge to becompleted within four weeks.This involved asystem of ‘Lego bricks’ stressed together by post-tensioning tendons.

PLACING AND STRESSINGThe bridge piers were prefabricated in two 60 tsections. After placing them in the pierfoot, thecomponents were stressed using two BBRCONA 1206 tendons. In total, nine piers were

Climate change has meant that an ever-increasing amount of water is flowing throughthe River Rhine and needs to be moved towards the sea without delay.Thatis why, as part of a flood prevention scheme inWageningen, a dam connecting

with the Lexkesveer ferry has now been replaced by a bridge. Ben Grundlehner fromNetherlands-based BBR Network member Spanstaal, takes up the story.

placed – at a rate of one pier per day.In the following two-week period, ten deck spanswere constructed using pretensionedprefabricated 20 m hollow core beams. Afterplacing the beams on the piers, they werestressed together in a transverse direction usingpost-tensioning tendons. In total, 200 BBR CONA0706 tendons were used. A concrete overlay wasnot necessary.

TRAVELLING IN COMFORTThe individual spans were made continuous byso-called bending joints, to give extra comfort tothose travelling by car across the new bridge. Allmovements were concentrated at the abutmentswhere expansion joints were built in.This solution made it possible to build a 200 mbridge within four weeks and without anyproblems being caused by water. And so the newbridge was opened for traffic on 4 August 2009,giving way to cars above – and free-flowing waterunder the bridge. �

TEAM &TECHNOLOGY

OWNER Rijkswaterstaat

MAIN CONTRACTOR Ballast Nedam Infra Midden

DESIGNER Grontmij

TECHNOLOGY BBR CONA internal

BBR NETWORK MEMBERSpanstaal B.V. (Netherlands)

LEXKESVEER BRIDGE, NETHERLANDS

BRIDGES

23CONNÆCT

The old Jamarat Bridge in Saudi Arabia wasbuilt in 1963, primarily for the convenience ofthe pilgrims and, ever since, has not only beenof great use during the religious festival, but hasalso become one of the many importanttourist attractions in Saudi Arabia.The oldJamarat Bridge was refurbished in 2006 toaccommodate even more people on thebridge and avoid accidents.

INCREASING CAPACITYAbout 4.2 billion Saudi riyals (US$1.2 billion)were allocated by the Saudi government tocarry out the expansion of the Jamarat bridgeand construction of new levels.This project hasalready helped prevent any injuries or deathfrom occurring among pilgrims, as had beenthe case in previous years.The bridge is now multi-storied to provide

more space.The Jamarat Pillars have also beenexpanded so that more people can performthe ritual without having to fight for a space atthe front.An emergency evacuation space hasalso been built in, so that the pilgrims can bespeedily removed from the bridge.The presentcapacity of the bridge is more than 500,000pilgrims per hour, but this will be reduced to300,000 pilgrims per hour to control themovement of pilgrims towards the holymosque while performing theTawaf rituals.

MAIN BRIDGE CONSTRUCTIONThe new main bridge consists of four levels,excluding the ground level, and is about 100 mwide. It was constructed by the segment-by-segment method, with columns only at thesides and two underpasses.To serve these levels there are11 escalators – four at the entrance to themain bridges and seven at the exit.Also there are 11 ramps at the entrance and12 at the exit, serving all directions – givingaccess to-and-from Mecca, Mina and Muzdalifa.Marwan Al Kurdi & Partners Co. was thesubcontractor for the erection of some 2,000precast prestressed girders for all the ramps.�

Jamarat Bridge in SaudiArabia is not only a place ofgreat religious significance,

but it also has a functional valueas transportation infrastructure.It is a pedestrian bridge that islocated very close to Meccaand Mina – and plays a veryimportant role during the Hajjpilgrimage. The pilgrims linethemselves up on the bridge inorder to throw stones at thethree Jamarat Pillars during the‘stoning of the devil’ – aceremony that is an integralpart of the Hajj.

TEAM &TECHNOLOGY

OWNERMinistry of Municipal and Rural Affairs

MAIN CONTRACTOR Saudi Binladin Group

DESIGNERDar Al-Handasah (Shair and Partners)


BBR NETWORK MEMBERSHuta-Hegerfeld Saudia Ltd (Saudi Arabia)Marwan Alkurdi & Partners Co. Ltd (Jordan)

JAMARAT BRIDGE, SAUDI ARABIA

Improved safety and space

24 CONNÆCT

The M6 Duna Motorway isa Public Private Partner-ship infrastructure project

in Hungary and runs in a North-South direction from Budapestto Pecs. One section hasalready been completed andJürgen Diatel from BBR Networkmember VORSPANN-TECHNIK advises that thesection between Dunaujvarosand Pecs will be completed by2011. The two bridges, knownas No. 993, are a major elementof this stretch of the newmotorway.

The project includes the construction oftwo similar bridges, each one with a totallength of 629 m. Both superstructures arebeing built using the incremental launchingmethod and consist of 13 spans with amaximum length of 50 m.The singleprestressed concrete box girder is 3.5 mhigh. In total, there are 46 standard 25 mlong sections and eight smaller 11 m longside sections.

UNIQUELY APPROPRIATEThe construction concept uses twodifferent types of post-tensioning. For thecentric tendons, BBR VT CONA CMIinternal with 0.6” diameter is being used.Over successive planning phases, theconcrete cross-sections were progressivelyreduced, thus four different types of CMItendon are being applied.The carriagewayslab will have 16 tendons with 19, 12 andsix strands and eight tendons with19 strands are being installed in the bottomslab.All tendons run over two sections. Half ofthe tendons are stressed at theconstruction joints and elongated by fixedcouplers. In the first three sections, differenttendon types are used. In the carriagewayslab, there are eight tendons each of BBRVT CONA CMI 1206 to 1906 and fromBBR VT CONA CMI 0606 to 1206. In thebottom slab, the tendons are all BBR VTCONA CMI 1906 and are continued withBBR VT CONA CMI 1506.It is only possible to meet the highrequirements of the design work because ofthe uniquely small centre spacing and edgedistance requirements of the BBR VTCONA CMI system, compared to otherproducts on the market.

F ive magnificent new viaductsare now taking shape, in an

area of Jaen province, southernSpain, which has been declared aNatural Park by the Governmentof Andalucía. David OlivaresLatorre of BBR PTE provides anoutline of this fascinating project.

We are responsible for two differentactivities during the viaduct construction –stressing of the 39 and 45 m spans anddeck positioning between piles.The precastdeck segments are being placed using alaunching girder..The 900 t of prestressingsteel applied to the project consists solelyof external BBRVT CONA CMEtechnology – the only construction systemused on the Despeñaperros viaducts.

CONSTRUCTION SEQUENCEAs construction of the first spancommences, four 500 t vertical andhorizontal positioning jacks are positionedover the piers at the beginning and end ofthe span. Next, the precast segments arejoined and correctly positioned, suspendedfrom the launching girder.

External polyethylene pipes are insertedinside the deck and are dragged andwelded. Once every tendon pipe is fixed inthe 2406 and 3106 anchorages, the steelstrands are fed into them and stressing ofthe span begins.When enough force isachieved along the deck, span positioning iscarried out using the four jacks.

CORROSION PROTECTIONCorrosion protection for the cables isprovided by the grouting of the 39 and45 m tendons.We used a special grout,which was in accordance with ETAG 013.It is a very satisfactory constructionprocess because all the span activities canbe finished in less than a week. �

Viaduct quintet in park

TEAM &TECHNOLOGY

OWNER Ministerio de Fomento

MAIN CONTRACTORFCC Construcción, S.A.

DESIGNERFCC Construcción Technical Services

TECHNOLOGYBBRVT CONA CME externalAdvanced shoring

BBR NETWORK MEMBER BBR Pretensadosy Técnicas Especiales, S. L. (Spain)

DESPEÑAPERROSVIADUCTS, SPAIN

25CONNÆCT

ECCENTRIC PTFor the eccentric post-tensioning, the BBRVTCONA CMB 4x0406 band system for externaltendons is being used. Each unbonded tendonconsists of 1606 strands placed in four double-extruded BBRVT CONA CMB bands.The lengthof the tendons extends from 141 m to 293 m.The deviation points are constructed asPE-saddles at the support cross beams with amaximum length of 3.34 m. After launching iscomplete, tendons are installed through theopenings created in the carriageway slab for thetwo steel beams used as a launching device.Thetendons are stressed – in one direction at bothends simultaneously – to 2,940 kN.As a consequence of the tough construction

schedule, the standard erectiontime of one week was reduced tobetween three and five days persection and working time wasextended to 24-hours-a-day, sevendays-a-week. Both superstructuresare being built simultaneously – andthe maximum weight of bondedtendons installed, stressed andgrouted per week is 35 t.Thanks to the excellent engineeringwork of FÖMTERV and Pont-TERVand the advanced technology ofour BBRVT CONA CMX system,we are able to build highlyeconomical bridge structures in an

impressively short time. Although boundaries canalways be pushed further, safety and qualityshould never be forgotten while focusing onconstruction time and costs. �

BRIDGES

TEAM &TECHNOLOGY

OWNER M6Tolna Autoplaya Koncesszions Zrt

MAIN CONTRACTORM6 Dunaujvaros – Szekszard Epitesi

DESIGNERFÖMTERV and Pont-TERV, Budapest, Hungary

TECHNOLOGY BBRVT CONA CMI internalBBRVT CONA CMB band


BRIDGES 993, M6 MOTORWAY, DUNAUJVAROS, HUNGARY

IMPRESSIVE SPEED

26 CONNÆCT

Günter Damoser from BBR Network memberVORSPANN-TECHNIK provides anoverview of two major bridge constructionschemes in the Baltic.The Riga South II Project consists of various bridgesand overpasses on a junction formed by the newtransversal road from the central districts of Riga tothe SouthWest.This continues on in a direct linefrom the newly constructed bridge over the RiverDaugava (Riga South I Project).The bridges are all being built as prestressedconcrete bridges on conventional shoring, post-tensioned with BBRVT CONA CMI 1906 tendons.Tendon layout is being performed in the usual way– with a construction joint between two regularconstruction sections, about half of the tendons(‘A’ tendons) are coupled with fixed couplerswhereas the other half of the tendons (‘B’ tendons)are continued without couplings into the nextconstruction section. In the next constructionjoint, the ‘B’ tendons are coupled. In a few cases,movable couplers are used to guide tendons intothe next construction section.The transversalbeams are also post-tensioned.Meanwhile, the Vairoga Bridge Project is a typicalmulti-lane railway overpass, consisting of twoadjacent 506 m long bridge structures.They arebeing built concurrently on conventional shoringand post-tensioned longitudinally with BBRVTCONA CMI 1906 tendons. Lengthwise, fourspans each form a continuous deck system,separated from the next by a road joint.Several years ago,VT began to promote andimplement post-tensioning systems in Latvianprojects and, with these bridges, we were able tosuccessfully continue that relationship. �

With their significant track record of completing over 50bridges in the Middle East region, BBR Networkmember NASA Structural Systems LLC was appointed

by main contractorWade Adams to perform the specialist post-tensioning works on the flyovers for the US$18 million DubaiBypass Phase III-Al Qudra project.

BRIDGES IN RIGA, LATVIA

Latvian continuation

TEAM &TECHNOLOGY(Riga South II Project/Vairoga Bridge)

OWNER OF BOTH PROJECTSConstruction Department, City of Riga

MAIN CONTRACTORSLatvijas Tilti / Latvijas Tilti and Tilts

DESIGNERS Celuprojects with Vektors-T andGiprostroymost / Tiltprojects



Warwick Ironmonger, General Managerfor Structural Systems’ operations in theMiddle East, and Mahesh Nayak,Contracts Manager for NASA StructuralSystems LLC, provide an overview ofthe project which will connect the BabAl Shams Resort road to the ArabianRanches roundabout – thus relieving thebusy Dubai Bypass road.

EAST & WEST BRIDGESThe flyovers included two identicalparallel (East andWest) bridges – eachone 418 m long with eight spans. Auniform cross-sectional depth of 2.3 mwas made possible for both the 44 mend spans and the considerable 55 mintermediate spans by adopting a post-tensioned solution wherein each bridgedeck consisted of five prestressed websforming a cast-in-situ four-cell boxstructure.Each web featured eight BBRVTCONA CMI 1906 tendons which ranthrough six construction stages. Half ofthe tendons were coupled and stressedat each of the five successiveconstruction joints to provide an evendistribution of the prestressing forces.After successful single-end stressing, eachof the tendons – up to 165 m long – weregrouted in less than 30 minutes usinghigh performance colloidal mixers, incompliance with the project specification.

Structural Systems’ remit, deliveredunder the vigilance of the RTA, includedthe supply of BBR post-tensioning kits,shop drawings related to the post-tensioning works, designing the anti-burst and splitting reinforcement, plusinstallation, stressing and grouting works.

COMPLEMENTARYEXPERIENCEThe Al Qudra Bridge project, whichconsumed a substantial 800 t of PTstrand, is the largest bridge projectcompleted to date by StructuralSystems in the Middle East region.WithStructural Systems currently undertakingthe post-tensioning works on thesignificant Nad Al Sheba Bridge project,also for the Dubai RTA, it is clear thatinfrastructure demand and BBRpresence are both growing in the Gulf.

TEAM &TECHNOLOGY

OWNERRoads & Transport Authority (RTA), Dubai

MAIN CONTRACTORWade Adams Contracting LLC

CONSULTANTWilbur Smith Associates & AlturathEngineering Consultants

TECHNOLOGYBBRVT CONA CMI internal

BBR NETWORK MEMBER NASA StructuralSystems LLC (United Arab Emirates)

DUBAI BYPASS PHASE III-AL QUDRA BRIDGES, DUBAI

PT relievesTRAFFIC TENSION

�

27CONNÆCT

This bridge project is located on the Shatt Al-Arab river atthe town of Al-Dair, some 40 km north of Basrah city.Whencompleted, the bridge will connect the communities on

either side of the river and provide a direct link to the Iranianborder. Safwan Ani of BBR Network member SPC describes theearly stages of construction work.

BRIDGES

Community connection

The bridge is made up of 13 spans – each span 36 m long, with five girdersto be installed on each span and the total bridge width is 15 m.SPC is constructing the girders and our responsibilities include submittingthe prestressing design calculation, bending and assembling thereinforcement cage on the casting bed, installing the prestressing ducts andanchorages, fixing the side forms, casting the girder, prestressing thetendons to the required force in two stages and grouting the ducts.Each girder will have five BBR CONA 1006 tendons and the anchor headswill be BBR CONA 1206. All design and expected elongation calculationswere carried out by BBR Headquarters in Switzerland. �

AL-DAIR BRIDGE, BASRAH GOVERNATE, IRAQ

TEAM &TECHNOLOGY

OWNER State Corporation for Roads and Bridges

MAIN CONTRACTORS Abdullah A. Al-Jiburi Contracting Company

PRESTRESSING & GIRDER FABRICATION Specialized Prestressing Company


BBR NETWORK MEMBER Specialized Prestressing Co (Iraq)

28 CONNÆCT

The Norwegian Roads Department decidedthat the three new crossings – underconstruction as part of the project to widenthe E6 from two to four lanes – should havea special design.The cable-stayed bridge atKolomoen features a deck which is carriedby 12 front stays, 12 back stays and fourcross stays.The bridge deck itself is made oflight-weight concrete and is 30 cm thick,except for the edge beam, where thethickness is 50 cm.

PYLON INSTALLATIONThe pylons are 30 m high and shaped like anequilateral triangle.They lean outwards fromthe bridge and there is no inter-connectionbetween the pylons.Purpose-made fixed BBRVTTOBE potbearings were used as flexible supports undereach pylon.The pot bearings were designed

with a pin-and-bucket guiding device on topof the bearing to simplify the positioning ofthe pylons during installation.Temporary support was provided by BBRVTCONA CMI single prestressing cables whichwere used to keep the pylons in position

during installation and stressing of the staycables. Spennteknikk performed all of the PTwork, delivery and installation of the staycables and delivery of the other purpose-made steel components – which wereproduced in our factory.

One of three important new crossingsassociated with the E6 highway wideningproject is at Kolomoen – between Oslo

and the 1994 Olympic resort of Lillehammer.Thenew bridge here will take traffic over the E6 at thisintersection between the E6 and the R3,approximately 150 km north of Oslo.The crossingis well-known from traffic news reports on theradio – because there are often long queues!

NETWORKING IN NORWAY

MOTORWAY INTERSECTION BRIDGE, KOLOMOEN, NORWAY

BRIDGES

29CONNÆCT

NETWORK SUPPORTDuring installation, we were assisted by theother companies in the SpennteknikkInternational group. Meanwhile, other BBRNetwork members provided support for ourproject – VORSPANN-TECHNIK assistedwith jacks, while BBR Polska assisted withexperienced staff and self-designed stressingequipment for installation of the stays. �

TEAM &TECHNOLOGY

OWNER Statens Vegvesen

MAIN CONTRACTOR Hæhre Entreprenør AS

CONSULTANT Johs. Holt AS

TECHNOLOGY BBRVT CONA CMI internalBBRVTTOBE pot bearingStay cable

BBR NETWORK MEMBERKB Spennteknikk AS (Norway)

Bearings are provided to allow structures– such as bridges, offshore installations andlarge buildings – to expand and contract,as well as transfer the loads from thesuperstructure to the substructure.Thereare two types of bearings commonly used– neoprene (elastomeric) bearings with orwithout sliding pad, and pot bearings suchas BBRVTTOBE pot bearings.Neoprene bearings are more desirable fortheir simplicity of installation andmaintenance-free performance. However,both load bearing and movement capacitylimit the application of neoprene bearingsto short spans and distances betweenexpansion joints.

POT BEARINGSPot bearings are available for large loadsand movements and are therefore thetype of bearing most frequently used. Potbearings consist of a base plate containinga rubber cushion inside a low cylinder orring which allows a small rotation in thebase plate.The top plate rests on a pistonwhich, in turn, rests on the rubber cushioninside the cylinder. Since this rubber disc isunder high pressure, a seal is required toprevent the rubber from squeezing out ofthe ‘pot’.The top plate can have one ofthree arrangements either allowing orpreventing movement – fixed, free

(multidirectional) or guided (unidirectional).Bearings must be installed by qualifiedpersonnel, such as the members of theBBR Network.

BBR VT TOBE POT BEARINGSThe BBR VT TOBE pot bearing familyconsists of three types – Type F, fixed,type A, multidirectional and type E,unidirectional. Standard bearings coververtical loads ranging from 520 to33,400 kN and horizontal forces from0 to 3,260 kN.They are designed to arotation/tilt angle of ±20 per mille andmovement capacities of ±50 mm and±100 mm respectively. In addition, guidedbearings can accomplish lateralmovements of ±20 mm. All modelsundergo a high quality surface treatmentincluding sandblasting, zinc/aluminumspraying and epoxy sealing as well aspainting. Naturally, BBR VT TOBE potbearings can be customized forconsiderably larger loads and movementcapacities, as well as different surfacetreatments upon request. All models aredesigned to European Norm EN-1337-5specifications and carry the CE-mark.BBR VT TOBE pot bearings stand out fortheir high capacity, low friction coefficient,low structural height, simple and safeassembly and short delivery time.

Technical insight:BBRVTTOBE pot bearings

BBR VT CONA CMI – 3106-140-186017 t, 15 cables in counter weight foundation

BBR VT CONA CMI – 1906-140-186010 t, 8 cables in the lateral axis on bridge deck

BBR VT TOBE pot bearings• 2 x BBRVTTOBE, type 110 F special, for pylon supports• 4 x BBRVTTOBE, type 30 F, for pendulum supports• 2 x BBRVTTOBE, type A and E

30 CONNÆCT

Major bridgeCONSTRUCTION

in mining subsidence area

TEAM &TECHNOLOGY

CLIENTFederal Republic of Germany, represented byDEGES Deutsche Einheit Fernstraßenplanungs-und –bau GmbH, Berlin

MAIN CONTRACTORGerdum u. Breuer Bauunternehmen GmbH,Fuldabrück, Germany

CONSTRUCTION PLANNERGerdum u. Breuer Bauunternehmen GmbH,Fuldabrück, Germany

INSPECTING ENGINEERKHP, König & Heunisch Planungsgesellschaft,Leipzig, Germany

TECHNOLOGYBBRVT CONA CMI internalBBRVT CONA CMB band

BBR NETWORK MEMBERVORSPANN-TECHNIK GmbH (Germany)

FRIEDETAL BRIDGE, A38 MOTORWAY, GERMANY

BRIDGES

31CONNÆCT

The Friedetal Bridge crosses through aformer potash mining area and thusrepresents an engineering challenge,

reports Dipl.-Ing.Thomas Weber of VORSPANN-TECHNIK who delivered a completeprestressing system for this exceptional project.

The Friedetal Bridge is one of two major bridges in the still missingsection of the A38 Südharzautobahn between Halle and Göttingen,Germany.The A38 is part of ‘Verkehrsprojekt Deutsche Einheit Nr.13’– see, page 57, CONNAECT 2009 for more about these projects). Itbegins at the motorway triangle Drammetal, south of Göttingen, isrouted through the Halle / Leipzig area, where it intersects with the A9motorway and terminates in the A14 near Parthenaue.The A38 isintended to relieve the traffic burden on the A2 which lies a bit furtherto the north and – together with the A7 between Drammetal andKassel, as well as the A44 south of Kassel – to provide an additionalconnection between the Halle / Leipzig area and the Ruhr region.With span lengths of 45 m, 65 m, 90 m, 85 m and 35 m in the endspans and 165 m in the main span, the Friedetal Bridge attains a totallength of 485 m.The height above ground is about 30 m.The A38crosses the Friedetal valley on two separate superstructures, each ofwhich is built from single-cell reinforced concrete hollow caissons.The hollow caisson cross-section attains its greatest height, 8.50 m, ataxes 40 and 50. Between these two axes, as well as in the end spans,the superstructure height is reduced to 3.5 m.The bridge is being built with both cantilever construction, as well aswith conventional support structure techniques.The cantileverconstruction begins at axes 40 and 50 and each consists of 15 con-struction segments per axis. A total of four cantilever form travelershave been employed to reduce construction time.This makes itpossible to work on both axes simultaneously.The fabrication of false-work sections is accomplished in parallel with work on the cantilever.BBRVT CONA CMI 1906 prestressing elements are being used forinternal prestressing.The longest prestressing elements in the course ofcantilever construction have a length of 154 m. Overall, theconstruction will consume 530 t of prestressing steel and 740 anchors.It was decided to use reinforced jacket tubes exclusively, becausealmost all prestressing elements will be enclosed in concrete.Once the gap is closed, the external prestressing elements can beinstalled.This application employs BBRVT CONA CMB 4x04 bandprestressing elements.The differing cross-section heights, as well asvarying span lengths, made selecting prestressing element guidance aspecial challenge – which on the one hand is able to meet the staticdemands and, on the other hand, does not produce geometric collisionpoints.There are 20 prestressing elements in each superstructure – thelargest of these are 220 m long.The total tonnage of externalprestressing amounts to 140 t. �

PHOTO CAPTIONSMain Picture:View from axis 60 in the direction of axis 10, south superstructurefinished, north superstructure under construction.Inset (main picture): Progress of cantilever construction outward from axis 40,cantilever forming traveler in construction segment 13.Picture 1:View of ‘hammer head’ at axis 40.Picture 2: External prestressing elements at axis 50, already tensioned.Picture 3: External prestressing elements, axis 50 in the background, in theforeground, anchoring pilaster for prestressing elements traversing the mainspan between axis 40 and 50.Picture 4:View of the bridge in the direction of axis 10.Picture 5:View from the crane at axis 50 in the direction of axis 10.

Pictures 1, 4 & 5, courtesy of Gerdum u. Breuer

41

5

4

32

32 CONNÆCT

The new B480n Talbrücke Eselbruch is currently the largest road constructionproject being undertaken by the regional roads authority in Hochsauerland – apopular tourist destination – in the German province of Nordrhein-Westfalen.The

project is a 3.75 km local avoidance scheme featuring a total of six bridges and a tunnel,near Olsberg, and will be completed – with the help of BBR Network member Spankern– in summer 2010.

This new route for national traffic willenhance internal development in theHochsauerland region, as well as itsaccessibility for tourism and leisure.TheTalbrücke Eselbruch bridge has spans of27.50, 39.00, 39.00 and 27.05 m and atotal length of 133 m.The bridge was castin situ as a double-webbed T-beam in twosections.The construction height is1.72 m. Originally, after initial calculations,15 post-tensioning tendons wereenvisaged, however, so much post-tensioning could not be accommodated in

Enhancing trade and tourismTALBRÜCKE ESELBRUCH, GERMANY

SEREDENG RIVER BRIDGE,SARAWAK, MALAYSIA

TEMPORARYFIXITYBBR Construction

Systems (Malaysia)Sdn Bhd was awarded a

con-tract to construct aprestressed concrete boxgirder bridge over theSeredeng River, near Sibu. Thebridge, which will give roadaccess between Tanjung ManisPort and internal areas,consists of a 165 m main spanand two 95 m side spans.

The cast in-situ balanced cantileversegmental method has been adopted,whereby one segment is cast at a time onform travelers to the left and right of thepier, inducing unbalanced moments to thepier. Due to the short piers, they arerelatively stiff, therefore the bridge is notmonolithically fixed to the piers – but hasinstead been designed to sit on pot bearingsto release any restrained axial forcesgenerated by creep, shrinkage andtemperature.The deck must not be allowed to transfermoments to the pier during or afterconstruction. As the deck is not connectedto the pier during construction, the twocantilevering deck segments from each pierneed to be stabilized. Our temporary fixitysystem involves temporary installation ofpost-tensioning to attach the deck to thepier.When the cantilever sections from thetwo piers have been stitched at the midspanclosure pour, the bridge becomes continuousand the fixity system is then removed.

such a small cross-section. So, twolongitudinal beams were designed andeight BBRVT CONA CMI 2206 tendonswere installed in every span. �

TEAM &TECHNOLOGY

OWNER StraßenNRW

MAIN CONTRACTORAlpine Bau Deutschland AG

DESIGNER GMG Ingenieurgesellschaft,Dresden


BBR NETWORK MEMBERSpankern GmbH (Germany)

A strut-and-tie system is being used tostabilize the bridge during the balancedcantilever construction stages. Steel struts areplaced 10 m apart on pilecaps and proppedagainst the deck at the web locations toprovide an effective lever arm for thesystems to resist unbalanced momentsduring construction.Vertical tie-downs –utilizing BBR CONA 1906 tendons – preventthe bridge from being raised off the steelstruts under all load combinations. Each tie-down has 19 15.24 mm diameter strands –with the dead end anchored in the pilecap,while the other end goes through the weband protrudes on top of the deck. Eachtendon is stressed to 70% UTS using a 480 tmultijack to hold the deck on the pilecap.Two permanent pot bearings are installed ontop of each pier.Ten 600 t capacitytemporary sand jacks – designed,manufactured and tested by the BBR team –are installed on top of the pier to protectthe bridge pot bearings from overloadingand excessive rotation during construction.

33CONNÆCT

BRIDGES

Cost-savings on concrete bridges are achieved partly through theconstruction method chosen which can reach up to 20% of totalconstruction costs and partly through the structural systemselected.Thus, the bridge construction method plays a significantrole and should be considered during the preliminary designperiod, with the help of the BBR Network.The construction method depends mainly on topography andinfluences bridge cross-section design as well as span. Basically, fivemajor techniques are employed. In addition, a wide range ofdifferent or adapted methods are used.

CONVENTIONAL FALSEWORKBridges of this type have a superstructure cross-section of solid orcellular construction.They are built on-site using formworksupported by temporary falsework. Formwork creates the shape ofthe concrete section and any internal voids or diaphragms.

BALANCED CANTILEVERWith the cantilevering method, the superstructure of bridges isusually built from one or more piers. Normally, the structureadvances from a short stub on top of a pier, symmetrically insegments to the mid-span or to an abutment – the load balancingmethod.The use of the cantilevering construction method, formedium and long span concrete bridges, is recommended –especially where it is difficult or impossible to erect scaffolding.

ADVANCED SHORINGThe advanced shoring method – or movable scaffold system – hasbeen developed for multi-span bridges over difficult terrain orwater where scaffolding would be expensive or not feasible at all.

A launching girder moves forward on the bridge piers span-by-span.The method is highly adaptable for a wide range of spans andtypes of superstructure, and it can handle cast in-situ concrete, aswell as prefabricated elements.

LAUNCHINGThe incremental launching method is particularly suited to theconstruction of continuous post-tensioned multi-span bridges. Itinvolves casting 15 m to 30 m long sections of the bridgesuperstructure in a stationary formwork behind an abutment andpushing a completed section forward with jacks along the bridgeaxis.The sections are cast contiguously and then stressed together.The superstructure is launched over temporary sliding bearings onthe piers. In order to keep the bending moment low in thesuperstructure during construction, a launching nose is attached tothe front of the bridge deck.

HEAVY LIFTINGHeavy lifting is a hydraulic lifting technique especially developed forextremely heavy loads and usually applied for the lifting of precastsegmental superstructure members. Span-by-span bridges providea very high speed of construction and are most often constructedusing an erection truss under the segments or an overheaderection gantry.

The BBR Network has a proven record – in all constructiontechniques – for all construction stages from preliminary designthrough to final execution. BBR Network members all over theworld maintain a specialized bridge construction equipment fleetfor any type of bridge design.

Technical insight:Bridge construction methods

TEAM &TECHNOLOGY

OWNER PublicWorks Department, Sarawak

MAIN CONTRACTOR Inai Kiara Sdn Bhd

TEMPORARY FIXITY DESIGNERBBR Construction Systems (M) Sdn Bhd

TECHNOLOGY BBR CONA internalBalanced cantilever

BBR NETWORK MEMBER BBR ConstructionSystems (M) Sdn Bhd (Malaysia)

Upon completion of the balanced cantileverconstruction, the sand is released graduallyfrom the jacks, transferring the weight of thebridge onto the mechanical pot bearings.Thecombination of prestress tie-down tendonsand steel struts, serves the vital function ofstabilizing the bridge during construction. �

34 CONNÆCT

The FreimannViaduct is a part of theA9 Nuremberg-Munich federal motorway,located just north of the Bavarian capital,Munich – between the Allianz arena and theHighlight Towers.This viaduct is about 580 mlong and, with a total of 20 sections, crossesover a number of transport routes – thusmaking it one of Munich’s most importanttransport nodes. A bird’s eye perspective,looking also at the eastern approach rampeast and western exit ramp, reveals why thisbridge structure has been dubbed‘Tatzelwurm’ – a snake-like mythical creatureoriginally attributed to the Alpine foothills.The FreimannViaduct was originally built inthe late 1950s.The peculiarity of this bridgewas its single-piece superstructure formedfrom multi-cell, prestressed concrete, hollowcaissons with prestressed longitudinal andtraverse beams. Severe corrosion damage toprestressing and reinforcing steel meant that

replacement of the entire structure becameunavoidable. In contrast to the originalsupport structure, the new design iscomprised of two separate bridgesuperstructures. In standard areas, theseconsist of two-rib prestressed concrete platebeams. In approach and exit ramp areas, thesuperstructure diverges into three and fourrib plate beams.The overhead launching girder technique waschosen by the project’s general contractor,DYWIDAG Bau GmbH, because of the

restricted construction space and the myriadof transport routes which cross the area.This type of construction utilizes a launchinggirder positioned above the bridge’ssuperstructure.The complete formwork hangson threaded rods from these main girders, thismeans that a crane cannot be used for thedelivery of materials from above, as is typicalfor the underslung launching technique.Thus,special solutions had to be found for manyconstruction stages.The new structure uses BBRVT CONA CMI1306, 1506 and 1906 prestressing elements.Prestressing element guidance differs in thevarious construction segments due to thedifferent spacing of piers.About one third ofthe prestressing elements have to be runthrough each construction segment joint in or-der to comply with standards.All jacket tubesfor prestressing elements were installed on siteby VT and the prestressing steel strands weresealed. One peculiarity here was that theprestressing elements to be routed furtherwere initially looped back into the currentsegment then, with the help of a lift mechan-ism, suspended beneath the overhead launch-ing girder and subsequently pulled out to thefront for installation in the next segment. �

PHOTO CAPTIONSTop: Overhead launching girder.View from the east.Superstructure construction for Nuremberg-boundtraffic lanes – Frankfurter Ring overpass.Inset:View of the launching girder from the front. Inthe background – Highlight Towers, Munich.Below:View of the completely reinforcedsuperstructure segment just prior to pouringconcrete – laterally looped-back prestressingelements.

FREIMANNVIADUCT, A9 MOTORWAY, BAVARIA, GERMANY

Rebirth of the Tatzelwurm

The Tatzelwurm served its purpose at the northern end of Munich foralmost 50 years and now a complex dismantling and constructionprocess is underway. Dipl.-Ing.ThomasWeber reports that his

company, VORSPANN-TECHNIK, was awarded the contract for carryingout all prestressing work on the new support structure – and the newTatzelwurm relies on BBRVT CONA CMI tendons.

TEAM &TECHNOLOGY

CLIENT Federal Republic of Germany,represented by Autobahndirektion Südbayern

MAIN CONTRACTORDYWIDAG Bau GmbH, Nuremberg

CONSTRUCTION PLANNERSRP Schneider & Partner Ingenieur-ConsultGmbH, Kronach

INSPECTING ENGINEERProf. Dr. Konrad Zilch


BBR NETWORK MEMBERVORSPANN-TECHNIK GmbH (Germany)

35CONNÆCT

BUILDINGS

BBRContech Northern Regional Manager, Keith Snow, reports onhow this challenging project was configured and delivered,demonstrating the benefits of the owner, contractor and designer

collaborating to produce an optimal solution that meets the requirementsof all stakeholders. It also reinforces the international partnering betweenBBR Network Members in New Zealand and Australia to deliver highperformance solutions and create local competitive advantages. �

INCREASINGretail accessibility

CAR PARK, SYLVIA PARK SHOPPING CENTRE, AUCKLAND, NEW ZEALAND

36 CONNÆCT

The Sylvia Park Shopping Centre is locatedat the demographic and geographic heart ofAuckland and boasts the broadest retail mixof any New Zealand shopping centre.The24-hectare Sylvia Park is Kiwi IncomeProperty Trust’s flagship retail asset and thelargest shopping centre in New Zealand. Itsprominence, exceptional location and publictransport links ensure easy access forshoppers.The Centre was completed in 2007 and itsimmediate popularity soon led to a demandfor extra car parking for the growingnumber of visitors.

RECOGNIZING PT BENEFITSThe new Sylvia Park North Eastern MultiStorey Car Park comprises four levelsconstructed on top of an existing two-levelcar park with a total area of 20,000 m2. It wasbuilt by Brookfield Multiplex who hadextensive involvement in the overalldevelopment and construction of the originalshopping centre. Brookfield Multiplex, throughprevious experience with post-tensioning,could see significant construction and deliverybenefits to the owner – and enlisted theexpertise of BBR Contech to propose analternative post-tensioned solution.

LOGISTICAL CHALLENGEThe car park building is bounded by thenorth retail mall, operational car parks andthe main circulation ring road and SouthernRail Line.The owner required minimaldisruption to customers during all phases ofthe construction. However the logistics ofdelivering and installing the originally specified1,060 17 m long precast floor units wasidentified as a huge delivery risk for theconstruction timeframe specified.Furthermore, the original design alsorequired large amounts of craneage andwould have created significant constructiontraffic movements on Sylvia Park roads whichare shared with the public. A differentapproach was therefore needed.

COLLABORATIVE DESIGNAlthough commonly used internationally,elevated post-tensioned floors have onlyrecently come into use in New Zealand withtypical construction usually taking the form ofprecast prestressed floor units.To ensure thebest possible result, BBR Contech worked withAustralian BBR Network partner StructuralSystems and project design consultant BullerGeorgeTurkington to develop the alternativethat met New Zealand seismic protectionstandards.The result is a post-tensionedelevated structure with band beams, created in20 separate 1,000 m2 pours.

“Typically car park buildings do not consider quality, userexperience or way finding as critical design issues. KiwiIncome Property Trust pays particular attention to every

detail and considers car parks as important as the retailexperience. The use of concrete, and in particular post-tensionedconcrete slabs, allowed for clean clutter-free soffits thatsignificantly improved user experience, quality and sightlines toexit points.It was realised during the design phase that post-tensioning wouldallow each level to be reduced by 200 mm having huge benefits forramp gradients, resource consent and construction cost.”Euan MacKellar, Sylvia Park Project Director, Jasmax / NH Architecture

37CONNÆCT

PT CONFIGURATIONThe post-tensioning configuration comprisedBBR CONA flat 0405 and 0505 system withtypical slab thickness of 150 mm betweenband beams.The overall floor depth waskept to a minimum by using band beamswith an overall depth of only 580 mm.Withclear spans approaching 17 m, thisconfiguration has produced a clean,structurally effective and attractive buildingwhich has been integrated seamlessly intothe existing shopping centre environment.The implementation of post-tensioning hasseen a reduction in materials and resourceswhilst delivering an architectural looksympathetic to the surroundings.This all tookplace whilst ensuring minimal disruption tothe ongoing retail operation and customersusing Sylvia Park. �

BUILDINGS

� No hogging or pre-camber from precast units with tolerances easier toachieve.

� Creation of a clean junction at the column / band beam connection giving atidy and consistent ‘off-the-form’ finish.

� Elimination of seating issues associated with precast floor units.

� Large floor pours achievable (1,000 m2 floor pours starting 2.00am – andfinishing 7.00am before the shopping centre opens) allowing the program tobe shortened.

� Integral soffit and band beam finish.

� Higher degree of slab integrity to minimize water ingress and lime leaching ontovehicles through minimizing slab cracking or hollow core units filling with water.

� Combines the crack minimization characteristics of post-tensioning with theapplication of a sealing additive into the mix design to provide water proofingto the top slab exposed to the elements.

� Elimination of eight columns per floor, compared to the original precast design– highlighting the flexibility of post-tensioning and insitu construction.

� An overall reduction in building height of 880 mm utilizing a post-tensionedsolution, against the originally specified precast floor units.This had botheconomic benefits and reduced the incline to the circulation ramps andspeed ramp.

Technical Insight:Advantages of the post-tensioned solution

TEAM &TECHNOLOGY

OWNER Kiwi Income Property Trust

MAIN CONTRACTOR Brookfield Multiplex

ARCHITECTJasmax / NH Architecture

STRUCTURAL ENGINEERBuller George Turkington

STRUCTURAL PEER REVIEWERHolmes Consulting Group

TECHNOLOGY BBR CONA flat

BBR NETWORK MEMBERBBR Contech (New Zealand) (construction)Structural Systems Limited (Australia) (PT design)

38 CONNÆCT

Chris Harris, from the BBR Network member inAustralia,Structural Systems Limited, reportson the largest post-tensioning building projectever undertaken in Australia which was awardedto SSL by Bovis Lend Lease as part of an ongoingStrategic Procurement Alliance.Top Ryde Shopping Centre Redevelopment will bea 130,000 m2 mixed use development, spread overnine floors. Stage 1 of the redevelopment is valuedat over A$440 million and will consist of a78,000 m2 shopping centre and entertainmentprecinct. In Australia, post-tensioned concrete isused by all the major developers and owners forvirtually all suspended shopping centre floors. Castin-situ post-tensioned concrete provides unrivalledflexibility and economy for these floors.Top Ryde includes about 1,600 t of post-tensioningfor all the suspended floors.At the peak of thestructure works, we installed, stressed and groutedover 170 t of post-tensioning in one month.Most floors are one-way slabs supported by one-way slab band beams, supported by cast-in-situstructural concrete columns, lift and stair cores.Structural Systems was awarded and is completingthe entire post-tensioning subcontract – eventhough Bovis Lend Lease split most other structuretrades and awarded them to multiplesubcontractors.Challenges included procuring materials, supervisionand labour to handle a project of this size. Materialswere sourced in advance and supervision andlabour were drawn from within our ownworkforce.With experience of delivering post-tensioning for many shopping centres, StructuralSystems is a reliable partner for delivering criticalstructure works to a tight program. �

The new Royal Children’s Hospital isbeing delivered as a Public PrivatePartnership (PPP) under the StateGovernment’s Partnerships Victoriamodel, with a private sectorconsortium, called Children’s HealthPartnership (CHP), responsible forbuilding and maintaining it for 25 yearswhile the Government owns andoperates it.The CHP consortiumcomprises International Public Projectsas equity holders, Bovis Lend Lease asbuilder, Spotless Group as facilitiesmanager and architects Billard Leece,Bates Smart HKS (US) – who alsoutilize consulting engineers Irwinconsult.This building not only aims to providestate-of-the-art facilities but also aims tobe Australia’s greenest hospital whilstoffering a child-focused healingenvironment set amongst engagingparklands with natural views.Located next to the existing hospital inParkville, Melbourne, the buildingconsists of a seven level, 165,000 m2

hospital and a three level 75,000 m2 carpark – with the value of this contractcoming close to A$1 billion.The projectis scheduled to be completed in twostages – completion of the first stage isdue in late 2011 and the second in2014.

Structural Systems began constructionon site in August 2008 and, bycompletion, will have installed some260 t of post-tensioned beamsthroughout the building, includingseveral multi-strand transfer beams.The BBRVT CONA CMI system wasused for all multi-strand installations. Six3106 anchorages were installed intotwo beams on the lower ground level.These beams were two meters deepand were required to span 25 meters.An additional ten 2206 anchorageswere installed into five precast transferbeams on Level 2 which were precastin order to reduce the beam width andto eliminate the need for double-heightformwork below.We are looking forward to theupcoming challenges presented by thissignificant and exciting project. �

TOP RYDE SHOPPING CENTRE,SYDNEY, AUSTRALIA

Record-breakingPT project

TEAM &TECHNOLOGY

OWNER Beville Group

MAIN CONTRACTOR Bovis Lend Lease

DESIGNER Arup

TECHNOLOGY BBRVT CONA CMI internalBBR CONA flatBBR CONA internal

BBR NETWORK MEMBERStructural Systems Limited (Australia)

TEAM &TECHNOLOGY

OWNERDepartment of Human Services,Victoria

MAIN CONTRACTOR Bovis Lend Lease

CONSULTANT Irwinconsult



As one of the largest projects currently under construction inAustralia and the State ofVictoria’s largest ever hospitalredevelopment project, the new Royal Children’s Hospital is a

massive undertaking and a milestone project. Charles Edgar, ProjectAdministrator for Structural Systems Limited outlines the scheme.

MILESTONE IN HEALTHCARE

ROYAL CHILDREN’S HOSPITAL,MELBOURNE, AUSTRALIA

39CONNÆCT

cutting the slab to make additional foundationsfor new machines – inevitably interferingwith production.

OUR ALTERNATIVE SOLUTIONTo stay within the budget, but – moreimportantly – to satisfy all the conditions, BBRAdria proposed a high performance, 40 cmthick post-tensioned slab on grade that ratherresembles a foundation mat for 10+ storeybuilding.The slab was designed as a flat slab oncolumns because of the poor soil conditions,plus jet grouting columns over which specialreinforcement cages were installed in the slab.For our client, this solution wasgroundbreaking – this way, they could dowhatever they wanted with the machines infuture, without any adjustments to theflooring.The requirement for vibration-freeconditions were also satisfied, as post-tensioning enables a much larger area of theslab (equal volume, equal mass) to bemobilized to counteract the vibrations, thusenabling a thinner slab.Finally, post-tensioning removed all the jointsand saved a lot of future maintenance costs.

PROJECT DELIVERYAs the warehouse consisted of a productionfloor and a few storage areas for heavy paperrolls and other equipment, the 40 cm thickslab was designed to cover one third of thetotal area. Other areas were differently loadedwith 50 and 80 kN/m2. For these, 25 and

BUILDINGS

In just three weeks, BBRAdria built 16,000 m2 ofhigh performance vibration-

free flooring for a high volumeprinting house. Damir Pavicicexplains that the completesatisfaction of their client wastheir biggest motivation.

At our first meeting with our client, werecognized that we were dealing with highlyprofessional people who wanted the perfectconditions for their four printing machines –each weighing over 300 t and each costingmuch more than the complete warehouseconstruction project itself! They also neededthe flexibility to be able to rearrange themachines and add new – and possibly evenheavier – ones in the future. Furthermore, themachines create a significant amount of vib-ration so one must not interfere with another.Finally, the soil was very weak so thesubcontractor improved it with jet groutingcolumns spaced at 2.5 or 4.0 m, depending onthe purpose and loadings in the correspondingwarehouse area.

ORIGINAL PLANThe original plan was to construct a 35 cmthick reinforced concrete slab on grade, with120 cm deep separate foundation mats foreach machine.The owner recognized that, forany future developments, this would mean

28 cm thick, respectively, post-tensioned slabson grade were provided.For the whole 16,000 m2 of slab, materialconsumption was 4,900 m3 of concrete, 70 tof prestressing steel strand and 230 t ofpassive reinforcement steel. In fact, thewarehouse consisted of two separate partsthat enabled all the works to be donesimultaneously.All 16,000 m2 of the flooring was cast in 16pours.They were all medium size pours, butexecuted day-by-day, along with the otherworks – with perfect organisation from themain contractor. It took us little over threeweeks to take the project from finished sub-base to completely finished floor – attemperatures not much above zero degreesCelsius.At the end of the day, BBR Adria providedaround 12% savings in the material of thewarehouse floor – and delivered exactly whatthe client needed.This project demonstratedthe ultimate in flexibility, performance,economy and speed – exactly what flat slabpost-tensioning is all about! �

PT PROOF FOR PRINTER

TEAM &TECHNOLOGY

OWNER Radin Aktiva (Zagreb, Croatia)

MAIN CONTRACTOR Zagorje Tehnobeton(Varazdin, Croatia)

DESIGNER AGH Studio (Zagreb, Croatia)

TECHNOLOGYBBRVT CONA CMM unbonded

BBR NETWORK MEMBER BBR Adria (Croatia)

“FOR OUR CLIENT, THIS SOLUTION WASGROUNDBREAKING – THIS WAY,THEY

COULD DO WHATEVER THEY WANTED WITHTHE MACHINES IN FUTURE,WITHOUT ANY

ADJUSTMENTS TO THE FLOORING.”

PRINTING HOUSE, ZAGREB, CROATIA

40 CONNÆCT

The Copernicus Science Centre is named after thewell-known Polish astronomer Mikolaj Kopernik (orin Latin Nicolaus Copernicus), who lived at the turnof 15th and 16th centuries and was the first topostulate heliocentric cosmology – which displacedthe Earth from the centre of the universe. In hishighly significant book,On the Revolutions of theCelestial Spheres (De revolutionibus orbiumcoelestium), he proved that the Earth – no longerthe centre of the universe – revolves around theSun and today, it is still accepted that the Sun is thecentre of the universe.The Copernicus Science Centre will be soonopen on the left bank of theVistula River in thecentre ofWarsaw, 10 minutes’ walk from the OldTown. It will be one of the first institutions of itstype in Poland. It includes interactive exhibitswhere everyone can carry out experiments ordemonstrations and learn about science (for moreinformation please refer to www.kopernik.org.pl).

PROJECT & SCOPEThe Centre will be a two storey building, with anarea of 15,000 m2 which will contain exhibitionhalls, laboratories, conference halls, a café andoffices. Parking places, studios and workshops willbe located underground.The planetarium, in ashape of a meteor, will form the multimedia partof the Centre.The whole building will besurrounded with the ‘Explorers’ Park’, wherevisitors will have an opportunity to discoverscience in the open air.BBR Polska’s scope of work includedcomprehensive execution of post-tensioning,covering the installation of 68 BBRVT CONACMI 1906 tendons – or, put another way, 72 t ofstressing steel in 18 post-tensioned beams.

Bartosz Lukijaniuk,M.Sc. and projectmanager for BBR

Polska reports that thecompany recently tookpart in the constructionof one of the mostprestigious buildings inWarsaw – theCopernicus ScienceCentre. Along with theNational FootballStadium, which is stillunder construction, theCentre is an extremelyimportant investment inWarsaw – both for thepeople and government.

WEIGHTY ISSUESThe designers sited the main part of the buildingover the existing road tunnel which contains oneofWarsaw’s major highways and runs parallel tothe river.The tunnel leads under the access road toSwietokrzyski bridge – where BBR stay cables areinstalled – and facilitates easy access to the bridge.The tunnel was not designed to sustain the loadsgenerated by such a large building, so thedesigners needed to come up with a way ofprotecting the tunnel.Their solution was totransfer the loads from the new building to aconcrete wall constructed outside of the tunnelstructure.This was achieved with a set of post-tensioned beams – the minimum distance betweenthe tunnel and the beams is only around 5 cm.

CREATIVE PT SOLUTIONAs a result of the designers’ idea, the PT platformwas created – a set of 16 post-tensioned beams(height 1.6 m, width 0.7 m, spaced every 3.5 m,length approximately 47.5 m) joined by concretebeams and slab. Each beam was stressed with fourBBRVT CONA CMI 1906 tendons. Each tendonwas equipped with one live end and one fixedend inaccessible anchorage.Additionally, two PT beams (height 1.3 m, width0.7 m, length approximately 32 m) were designedto transfer the load from the building to thecolumns of the underground car park. Each beamwas stressed and equipped as described above.

PT INSTALLATIONThe main contractor wasWarbud S.A., one of thelargest construction contractors in Poland. Goodco-operation with the contractor resulted in aproblem-free delivery of the post-tensioning works.

COPERNICUS SCIENCE CENTRE,WARSAW, POLAND

41CONNÆCT

Because the designer decided to useinaccessible anchorages, all strands wereinstalled before the beams were concreted.The PT platform was divided into foursections with four post-tensioned beams ineach.The slab was concreted after the beams.Each beam is supported on four walls – twoat the ends and two located about fivemeters from the ends.Tendon layout wastherefore designed as a parabolic curve andthree vents were installed at the two highestpoints and at the lowest point, betweenanchorages – in addition to the two ventsactually at the anchorages.The two additionalbeams were concreted later, as they were ina different location.

STRESSING & GROUTINGThe stressing sequence for the PT platformassumed that the tendons were stressed intwo stages. During the first stage, one half ofthe tendons were stressed to total designforce and in the second stage, the remainderwere stressed likewise.The two additional PTbeams above the car park were stressed inone stage.Grouting was carried out just after stressingoperations had finished – we performedthree grouting operations after the threestressing sessions.Thanks to BBR’s outstanding PT technologyand professional team, the CopernicusScience Centre building can stand above the

tunnel. Even Copernicus himself would haveapproved of the innovative thinking andpractice applied to this iconic building whichbears his name. �

BUILDINGS

TEAM &TECHNOLOGY

OWNER Warsaw City Council

MAIN CONTRACTOR Warbud S.A.

ARCHITECTRAr-2 Laboratorium Archiketrury Gilner + Kubec

STRUCTURAL DESIGNERBuro Happold Polska Sp. z o.o.


BBR NETWORK MEMBERBBR Polska Sp. z o.o. (Poland)

SCIENTIFIC SOLUTION

42 CONNÆCT

As part of the regeneration of Cardiff citycentre, the new St David’s 2 schemerepresents a £675 million investment, totaling89,891 m² of retail-led mixed-usedevelopment, with over 100 stores and 300luxury roof top apartments, built as seventowers above the shopping centre.The size of the floor plate meant that eachlevel was typically constructed as sevenpours.The frame contractor elected to utilizea slab and beam configuration. StructuralSystems supplied the BBR CONA flat 0305post-tensioning system for the reinforced

deck slabs and a BBR CONA flat 0605system for the 525 mm x 16 m span beams.The car park sits on a transfer slab at levelthree and is tied to a stair core in the centreof the building. By introducing post-tensioningtechniques, the slab depth for the car parkwas reduced to typically 150 mm –permissibly the thinnest depth for a car parkslab – with some areas at 175 mm andnominally 300 mm thick.The beam tendonswere mainly 36 m long, although in someinstances 56 m long double end stressedtendons were used.

The construction phase went smoothly, eventhough there were areas of complexitydemanding a close interface between thepost-tensioning designers and the servicesengineer who required multiple penetrationsthrough the post-tensioned beams. Clear anddetailed communication was maintained withthe contractor throughout the project, fromdesign to completion on site.The quick erection of the formwork system,in conjunction with the efficient poursequence offered by the Structural Systemsteam, enabled the contractor to completethe frame in 27 weeks.Using post-tensioning had massiveenvironmental benefits over traditionalreinforced concrete and steel structures,which was important for such a largeproject.The use of post-tensioning reducedslab depths significantly so that, overall, lessconcrete and substantially less rebar wasused – which was extremely beneficial to theclient in terms of program and budget. �

ST DAVID’S CENTRE CAR PARK, CARDIFF, UK

Greener parkingRichard Gaskill of Structural Systems – the BBR Network

member in the UK – explains that significantly moreadditional parking was required to service the St David’s 2

development in Cardiff which led to the construction of a fivelevel, multi storey car park, totaling in excess of 50,000 m². Thisgives the new centre a total of 3,000 parking spaces and thedrama of the development is heightened by the particularlystriking elliptical ramp access to the car park.

TEAM &TECHNOLOGY

OWNER St David’s Partnership

MAIN CONTRACTOR Skanska Construction

CONCRETE FRAME CONTRACTORP.C. Harrington Contractors Limited

DESIGNER Arup / Structural Systems (UK) Ltd


BBR NETWORK MEMBERStructural Systems (UK) Ltd

“USINGPOST-TENSIONINGHADMASSIVE ENVIRONMENTALBENEFITSOVERTRADITIONAL

REINFORCEDCONCRETEANDSTEEL STRUCTURES,WHICHWAS IMPORTANT FOR SUCHALARGE PROJECT.”

43CONNÆCT

Sean Doherty, Manager forQatar and Bahrain, for BBRNetwork member NASA

Structural Systems gives anoverview of the first projectsuccessfully completed sincehis company established apermanent base in Doha, thecapital of Qatar.Qatar Airways is developing a new 4-star, 400-bedroom hotel, near their base at DohaAirport.The hotel will also offer retail shops,restaurants, meeting rooms, a business centre,health club and swimming pool.The project covers a total area ofapproximately 45,000 m2, including abasement level, ground floor and level 1podiums, in addition to two six-storey towers.The main contractor, Gulf ContractingCompany (GCC), appointed us to design,supply and install post-tensioning – from theground floor to roof level.The ground floor and level 1 podium levelswere each broken into ten pours, with eachpour separated by a combination ofexpansion joints and / or delayed pour strips.A post-tensioned band beam and slabsolution was adopted for these lower levelsdue to the magnitude of the loadingsspecified, the need to transfer the swimmingpool loads along with several transfer columns

supporting the tower levels above, and thepresence of significant spans – often upwardsof 14 m – between supports.The PT slabs were generally 200 to 250 mmdeep and band beams ranged between 400to 800 mm deep, with transfer beamsthickened to upwards of 1,800 mm deep.On level 2, a PT band beam and slab solutionwas adopted to transfer load from the bladewalls supporting the majority of the upperfloors to the columns below.The typical levels for both towers consisted of250 mm deep PT flat plates, spanningbetween the blade walls that transferred atlevel 2.The main contractor’s construction programdictated a six month period for the design

and installation of 225 t of post-tensioning andfor pouring 23,000 m3 of concrete.Working24-hours-a-day and using the BBR CONA flatPT system, the post-tensioning works werecompleted on program – and thus thecontractor’s key milestone date was achieved.

�

BUILDINGS

Checking in ON TIME

TEAM &TECHNOLOGY

OWNER Qatar Airways

MAIN CONTRACTORGulf Contracting Co.WLL

CONSULTANT GHD Global Pty Ltd


BBR NETWORK MEMBER NASA StructuralSystems LLC (United Arab Emirates)

QATAR AIRWAYS 4-STAR HOTEL, DOHA, QATAR

44 CONNÆCT

The US$730 million Ajman One mixed-usedevelopment project is currently thelargest building project BBR Network

member Structural Systems has undertakensince setting up operations in the Middle East in1997.Warwick Ironmonger, General Manager ofStructural Systems’ Middle East operations andJeff Flynn, Operations Manager for Buildings forNASA Structural Systems LLC, give an overviewof the project and the challenges presented bythis important fast-track project.

Ajman One will be a world class residential, commercial and hospitalitycomplex.When complete, the 12 towers will consist of 3,000 (1, 2 and3-bedroom) apartments, housing up to 6,000 residents and settingnew trends for contemporary design. Ajman One will combine all theneeds of a modern business lifestyle – a one-stop destination offeringshopping, leisure, residential, business and hotel facilities within a singledevelopment.

ECONOMIC SOLUTIONThe top podium level and all the 28 / 34 storey tower floors wereproposed, by the Consultant, to be post-tensioned flat plates – tospeed up the construction program and serve as an economicalsolution to the slab spans in excess of 10 m.Having proven their professionalism and dedication to the maincontractor Al Zamalek General Contracting LLC, via successfulcompletion of the post-tensioning works for them on over 20 towersin Ajman, NASA Structural Systems LLC was appointed to take on thechallenge of the design, supply, supervision and installation of 2,500 t ofpost-tensioning for the 500,000 m2 associated with the podium leveland 12 towers that make up the first phase of Ajman One.Bonded BBR CONA flat post-tensioning tendons – both five strandand three strand – were incorporated into the design of the podiumand tower levels, where careful detailing was employed to deal withthe particular constraints of the various structural elements.

CONSTRUCTION DETAILINGStructural Systems detailed the typical tower floors supporting brittlemasonry partitions within the 270 mm slab depth – nominated by theConsultant in order to control deflections within the 10 m spans.However, for the top podium level, it was decided to construct300 mm thick flat slabs with drop panels – 450 mm deep x 3,000 mmsquare – as a means of dealing with the ‘punching’ shear, at slab /column interfaces, created by the unusually high landscaping loads.Structural Systems considered it prudent to detail a bottom mesh ofconventional reinforcement to deal with shrinkage concerns, given theunusually high degree of restraint to shortening provided by thesignificant core and shear walls, combined with the large pour lengthswhich exceeded 50 m.A 28-day delayed reinforced pour strip wasemployed for the central podium area – effectively breaking this 72 mlong zone into two or three zones during construction – to providesuitable stressing access for the slab tendons and minimize slabshortening, as well as resulting moments in the support columns.

RISING TO THE CHALLENGENearly 225 t of strand was required for the 22 pours to the podiumlevel alone, which covered almost 43,700 m2.This, combined with theneed to construct the 12 towers simultaneously, provided StructuralSystems with quite a challenge if they were to meet the maincontractor’s daunting construction program milestones.Rising to the challenge, installation of the 6.5 t and 10 t in the typicaland podium pours was generally achieved within 12 hours and 24hours, respectively – and between 200 and 240 t of 12.7 mm diameterstrand was routinely installed, stressed and grouted each month. Quitean achievement for the Structural Systems team!The use of post-tensioning on this project not only allowed the setmilestones to be achieved, but also gave the main contractor theadded advantage of being able to remove the formwork within onlyfour days of casting the slabs. �

TEAM &TECHNOLOGY

OWNER Aqaar Properties LLC

MAIN CONTRACTOR Al Zamalek General Contracting LLC

DESIGNER National Engineering Bureau (NEB)


BBR NETWORK MEMBER NASA Structural Systems LLC (UAE)

Toweringchallenge

AJMAN ONE– PHASE 1, UAE

45CONNÆCT

In order to make public transport more convenient,the Singapore Government decided to do more tointegrate the bus interchange and Mass RapidTrain (MRT) stations – and even turn them intolifestyle hubs, together with shopping malls.Currently, three such integrated developments areoperational – the Ang Mo Kio,Toa Payoh and theSengkang Interchange.Two more are beingconstructed at Boon Lay and Clementi. BBRConstruction Systems is currently involved in theClementi Interchange which is targeted forcompletion by mid-2010. BBR ConstructionSystems was also involved in the development ofSengkang Square in 2002 and, in 2007, therebuilding of the AMK Hub.

By mid-2010, the site at ClementiTown Centre which is occupied bythe existing bus interchange will bere-developed into a modern 40-storey complex with an integralnew air-conditioned bus terminal, a25,000 m2 shopping mall andresidential tower blocks consisting of388 units.This project will rejuvenatethe Clementi Town Centre into amodern hub and forms part of theoverall estate renewal strategytogether with the NationalUniversity of Singapore nearby.Post-tensioned beams and precastslabs were provided at the podiumlevels to achieve the greaterclearance span required toaccommodate the turning radius ofbuses at first storey level.The beamspan varies from 25 m to 30 mclear and supports various types ofloading depending on their usage.In order to maximize the capacity /self-weight ratio, all beams aredesigned individually, based on theirlength and also the applied load –as well as the sizes of the BBRCONA castings and anchorages tobe used.

The post-tensioned beams are designed to Class 1structure (BS8110, 1997) specification in order toprovide flexibility – allowing the owner to convertthe usage of the floor area when necessary. Dueto the limitations imposed by beam size and thehigh applied forces of a Class 1 structure, ‘stagestressing’ is required for all beams. �

BUILDINGS

TEAM &TECHNOLOGY

OWNER Land Transport Authority (LTA) / HousingAnd Development Board (HDB)

MAIN CONTRACTOR China Construction (SouthPacific) Development Co. Pte. Ltd

C&S CONSULTANTSurbana International Consultants Pte. Ltd


BBR NETWORK MEMBER BBR Construction SystemsPte. Ltd. (Singapore)

As a city state, Singapore is the second most densely populated country in the world.Today, roads take up12 percent of our total land area and the demands on our land transport system are set to increase by60 percent, from our current 8.9 million daily journeys to 14.3 million by 2020. Making public transport the

centre-piece of our land transport system will be crucial to keep congestion in check and help protect theenvironment, observes Lee ChongWhey of BBR Construction Systems.

INTEGRATED HOME,TRANSPORT & RETAIL DEVELOPMENTS, SINGAPORE

PHOTO CAPTIONSTop Left: AMK Hub – integrating bus terminal and retailmall under one roof, directly opposite is an undergroundpass connecting it to the Ang Mo Kio MRT station.Top Right: Clementi Town Centre – Singapore’s latestintegrated transport and lifestyle hub is under constructionwith the help of BBR Construction Systems.Bottom Left: Sengkang Square – Singapore’s first integratedtransport and lifestyle hub, integrating bus terminal, MRTstation, LRT station, shopping mall and a condominium.

Integrating transport

Leading building firm, LeightonContracting (Abu Dhabi) LLC, turned tothe experience of Structural Systems toprovide the alternative design for thepost-tensioned slabs associated with thetwo basement level car parks and thearchitecturally impressive ground floorlevel.An economical solution was present-ed and, in turn, adopted for the projectto the benefit of the contractor andclient alike.The strength of the alternativedesign was the elimination of drop panelsat the basement levels and introductionof a flat plate, providing a simplified form-work solution, saving time and money.Working within the constraints ofperimeter retaining walls and the overalllength of the structure being in excessof 200 m, the Structural Systems’ designteam detailed an effective and easy tobuild temporary expansion joint alongthe perimeter and incorporated pourstrips at locations which caused minimalconcern to the builder.With typicalcolumn grids of 9.3 m x 9.3 m, the slabdepths were a consistent 250 mm thickflat plate for the two basement levelswith the ground floor incorporating somethicker sections and drop panels to caterfor increased design loads, which reachedup to 40 kPa in zones.

Over 300 t of 12.7 mm diameter pre-stressing strands were installed utilizingthe BBR CONA flat, fully bonded system.Average pour sizes throughout the workswere approximately 1,500 m2.The design of conventionalreinforcement, including significantpunching shear reinforcement, requiredsound detailing to ensure effective co-ordination with post-tensioning tendons.Another successful project for NASAStructural Systems LLC.The benefitsassociated with early striking and re-useof formwork had the flow-on effect ofless materials handling and which canallow the following trades to commencesite works earlier. Post-tensioning is nowthe preferred construction solution forfurther floors of the building. �

Abu Dhabi is a city like no other at present and itsmaster plan in relation to building works isbreathtaking. Jim Karabatsos, from BBR Network

member,NASA Structural Systems LLC, reports on theirpost-tensioning design and construct package for the TDICHeadquarters building on the waterfront in the area of AlMaqtaa, just off the main island of Abu Dhabi.

46 CONNÆCT

The Magic Box is situated in Madrid, the capital ofSpain. BBR PTE’s David Olivares Latorre reportsthat it is an enormous box made of concrete andsteel with three mobile roof covers that can beopened or closed, depending on the event takingplace inside – and the weather conditions!The Magic Box is an 82,520 m2 complex containingthree tennis courts – the Main court has seatingfor 12,000 people, the Opera court accommodates3,200 and Circo court 2,700 people.All the courts are provided with bascule roofcovers.The largest is 103 m long and 73 m wide.The construction incorporates the indoor tennisbuilding with 11 indoor tracks, the tennis gardenwith 16 tracks, restaurants and administrative offices.The post-tensioning we used for this project wasthe BBR CONA flat slab bonded post-tensioningsystem using 0.6” diameter strand, with fourstrands per anchor – and we used in excess of200,000 kg of prestressing steel. �

MAGIC BOX ATHLETIC COMPLEX,MADRID, SPAIN

Tricks of the trade

TEAM &TECHNOLOGY

OWNER Ayuntaminento de Madrid

MAIN CONTRACTOR FCC Construcción, S.A.

DESIGNERTechnical Services of FCC Construcción & Fhecor


BBR NETWORK MEMBER BBR PTE (Spain)

TDIC HQ,ABU DHABI, UNITED ARAB EMIRATES

Alternative design delivers benefits

TEAM &TECHNOLOGY

OWNER Tourism Development &Investment Company of Abu Dhabi (TDIC)

MAIN CONTRACTOR LeightonContracting (Abu Dhabi) LLC

CONSULTANT Surbana InternationalConsultants Pte. Ltd


BBR NETWORK MEMBERNASA Structural Systems LLC(United Arab Emirates)

47CONNÆCT

The Claremont Quarter Project is a mixed-use development, in the already thrivingClaremont Town Centre. Sean Kelly of

Structural Systems Limited – the BBR Networkmember in Australia – explains how theredevelopment of the existing Claremont Arcadewill incorporate work, shopping and livingwithin the one ‘urban village’.

The Claremont Quarter offers 30,000 m2 of retail space containedover two levels, 77 residential apartments, 600 m2 of commercialoffices and 1,500 car spaces. Due for completion in 2011, the integratedcommercial development is a joint venture between BrookfieldMultiplex Limited and Hawaiian.The popular precinct locatedbetween city and surf is set to provide residents a combination ofentertainment, shopping, work and luxury apartment living.Structural Systems was awarded the design and construct contractfor the post-tensioned banded slab construction for Levels 1 to 5.An alternative price was considered for a flat slab construction –however, the east-west banded slab maximized the benefits for allstakeholders on the project.The design is being spearheaded byStructural Systems’ Melbourne office, whilst project management andsite labor has all been sourced locally through our Perth office.Loading in the retail levels (1 and 2) has created some designchallenges – with live loads of up to 12.5 kN/m2 and constructionloads up to 15.0 kN/m2. As a result, some north-south beams wereintroduced to improve the serviceability and strength of the bandedslab. Coles implemented a turntable to assist with deliveries – whichrequired the design of beams up to 1,300 mm deep for the11 kN/m2 (superimposed dead) and 12.5 kN/m2 (live) loads.Thestrength of concrete used in the design is 40 MPa.The BBR CONA flat system has been implemented for theconstruction, with a total of 507 t of 12.7 mm strand being usedthroughout Stages 1 and 2.The general layout of the east–west bandedslab incorporates 2,200 / 2,800 mm wide splayed band beams withfour 0505 tendons in each beam.Typically, there are two 0405 tendonsrunning east–west in the slab between bands (generally 160 – 185 mmthick) at roughly 2,000 mm centers.These cables are for compressiononly.The north–south tendons comprise mainly 0405 tendons at1400 mm centers, their profile is relatively uniform thanks touniversal column spacings in the car park levels and typical bandbeam widths.The post-tensioned slabs have been split up into 113 pours, with 70pours in Stage 1 and 43 in Stage 2.The large number of pours hasallowed multiple levels to be constructed at the same time giving themain contractor a tighter construction program and greater flexibility.With the BBR CONA flat system in place, a significant saving in rein-forced concrete has been achieved, promoting the use of post-ten-sioning and proving it a viable option for similar projects in the future.

BUILDINGS

TEAM &TECHNOLOGY

OWNER Hawaiian and Brookfield Multiplex Developments

MAIN CONTRACTOR Brookfield Multiplex Constructions

DESIGNER Janine Ralev – Structural Systems Limited


BBR NETWORK MEMBER Structural Systems Limited (Australia)

WORK, LIFE.... and shopping balance!

CLAREMONT QUARTER, PERTH,AUSTRALIA

�

48 CONNÆCT

With its striking design by Kohn Pedersen Fox Architectsand structural design input from Arup, PaddingtonCentral has been developed to the highest levels of

sustainability and is expected to receive the top BREEM rating of‘Excellent’. Structural Systems (UK) Ltd was brought in by theframe contractor, P.C. Harrington Contractors Limited, to advise ona suitable system for the post-tensioned floors – Richard Gaskilltakes up the story.

Paddington Central, part of the PaddingtonWaterside Development, is located onPaddington’s former railway goods yard,along the northern side of Kingdom Streetand south of the A40Westway inPaddington,West London. Comprising threebasement levels with ten storeys above –totaling nearly 209,000 m² of which all,except the lower basement, were post-tensioned – the structure makes animpressive addition to the Paddington BasinDevelopment inWest London.Developed by Development Securities PLCand built by Skanska, the building is part of amajor regeneration project around the newgrassy amphitheatre of Sheldon Square.

PT CHALLENGEWe proposed the BBR CONA flat 0505bonded post-tensioning system with three tofour strands per anchor.There were numerous buildability issues toovercome at the design stage.The basementlevels and podium had numerous stepsbetween the slab surfaces which ranged from500-800 mm in depth.This made theinstallation of the post-tensioning moredifficult and required a great deal of co-ordination between all parties involved in thedesign and installation.The design alsodemanded three to four different slab depths,on the sub-podium levels, ranging from 275mm to 325 mm to cater for varying spansand loading conditions.

COMPLEX SHAPEThe building was a complex shape – with arange of internal penetrations of 18.65 m x2.1 m.To further complicate issues, there wasalso a 3.2 m long cantilever to cater for.Typically, the structural layout required spansof 9.65 m x 9 m – but in some cases thiswas increased locally to 11 m.To the rear of the building at Level 0, a9.65 m long x 450 mm deep x 1200 mmwide post-tensioned beam was required totransfer a point load of 250 kN dead load(DL) and 60 kN live load (LL). Internal panswere used on Level 0 due to the limitedaccess to the edge of the slab and, again, arange of slab depths from 275-400 mm wasrequired.The loading for Levels 2-8 were 0.9 kN/m²(DL) and 3.5+1 kN/m² (LL) with a claddingload of 2.75 kN/m.Levels 1-9 used a typical combination of

Sustainable futurePADDINGTON CENTRAL, LONDON, UK

49CONNÆCT

270 mm and 310 mm thick post-tensionedslabs which were constructed as three poursper level.Level 8, however, also required a post-tensioned transfer beam which was 10.9 mlong x 700 mm deep x 900 mm wide andhad to accommodate two slots to allow forservices to pass through the beam.There were also minor changes to the slab

depths at Level 9 due to a difference in theloadings – 0.9 kN/m² (DL) and 3.5+1 kN/m²(LL) with a cladding load of 4.0 kN/m – andthe addition of 750 mm deep x 900 mmwide post-tensioned transfer beams totransfer point loads – of 235 kN (DL) and365 kN (LL) – from the roof structure.Level 10 had increased loadings of2.75 kN/m² (DL) and 7.5 kN/m² (LL), plus a

cladding load of between 2.75 and 7.0 kN/m,requiring a 325 mm thick slab overall.

FUTURE PROOFINGTo facilitate potential changes of use of thebuilding or parts of the building over time,we were required to allow for subsequentpenetrations through the slab.Accordingly, webuilt in a certain amount of redundancy intothe design to allow for these penetrations tobe undertaken without affecting the structuralintegrity of the slabs.The locations of theseadditional penetration points were marked onthe ‘as built’ drawings we provided. �

BUILDINGS

Paddington, historically in the county of Middlesex, was one of the many villages whichbecame part of London. In the 1830s, the temporary Paddington Station – the Londonterminus of the GreatWestern Railway – stood on very the spot that PaddingtonCentral is being constructed today.The railway’s development was inspired by Bristol-based merchants who, by providinggood transportation links with the nation’s capital, hoped to ensure their city remainedthe second most important port in England.After Isambard Kingdom Brunel’s new – and permanent – Paddington Station wasopened in 1854, the temporary station was converted into a railway goods depot.Other claims to fame for the area include the Grand Union Canal – the Paddington armopened in 1801 and provided an important trading route to the Midlands. And it was atPaddington’s St Mary’s Hospital, in 1928, that Sir Alexander Fleming discovered penicillin.Paddington Bear arrived on the scene much later, in 1958 – since when, he has ensuredthat children the world over know the name of one of London’s famous stations!

In Focus:London Paddington

TEAM &TECHNOLOGY

OWNER Development Securities PLC

MAIN CONTRACTOR Skanska Construction

CONCRETE FRAME CONTRACTORP.C. Harrington Contractors Ltd

DESIGNER Arup / Structural Systems (UK) Ltd



“THEREWERE NUMEROUSBUILDABILITY ISSUESTO OVERCOME AT

THE DESIGN STAGE.”

50 CONNÆCT

Janine Ralev reports that the key selection factorswere our alternative design featuring the use ofpost-tensioning in the tank slabs and the mainwalls of the structure, as well as the alternativeconstruction method proposed for building thewalls using a specially designed in-house movingformwork system.Structural Systems’ scope of works includedstructure design, concrete, reinforcement, post-tensioning and formwork, documentation, supplyand installation of concrete, reinforcement andpost-tensioning and site supervision.

PROJECT PURPOSEThe purpose of the project was to increase theSouth Eastern sewage capacity to serve thegrowing population in this area.The current six

existing aerating tanks had reached their capacityand four new aeration tanks, with a provision fortwo future tanks on the same site, were nowrequired.Our structure package included the design andconstruction of four additional concrete tanks andassociated concrete settled channels, mixed liquorchannel, return activated sludge channel (RAS),construction of switch room and related pumpstation, access walkways, precast baffle walls,suspended concrete slabs and precast concretetie beams.

ALTERNATIVE DESIGNEach concrete tank cell is approximately92.5 m long by 50 m wide and has 6 m high wallsand an operating volume capacity of

Structural Systems Limited was selected to design and constructfour large aeration tanks, at the Eastern Treatment Plant atBalgholme, south east of Melbourne, Australia.

AERATIONTANKS, EASTERNWATERTREATMENT PLANT, AUSTRALIA

Water industryinnovation

51CONNÆCT

27 ML. Our alternative design solution was apost-tensioned insitu tank construction.The design was carried out in accordancewith AS 3735 – the Australian Standard forconcrete structures for retaining liquids – withadditional requirements on durability of thestructure to deliver a design life of 100 years.Each tank cell and related channels weremodeled and designed using commercialFinite Element Software ‘Strand7’ todetermine the internal stresses at variousstages of the life of the structure. Internalsoftware was developed to incorporate allthe possible load combinations – in someinstances, up to 40 load cases wereconsidered – and determine the envelope ofactions for final design.

INSTALLATIONThe floor slab was cast in eight individualpours – approximately 50 m by 60 m each.The slab post-tensioning was applied toprevent forming of initial shrinkage cracks �

TANKS&SILOS

Facts & figuresProject footprint 220 m x 120 mConcrete poured 16,000 m3

Slab area 24,000 m2

Post-tensioned walls 2,200 lmSlab infills 2,000 mWall infills 700 m2

Post-tensioning 350 tReinforcement 2,500 t

52 CONNÆCT

and to allow the construction of the walls tocommence.The walls were cast without any horizontaljoints in 20-22 m long pours using aninnovative moving formwork gantry systemdeveloped in-house. Four separate gantrieswere manufactured to speed the constructionand to allow the tank and three channel wallsto be built simultaneously.The main wall reinforcement was fullyprefabricated on site and then lifted into place– except for the corners of the walls –because of congestion and the need for specialco-ordination with the post-tensioned ducts.Horizontal post-tensioning was installedbetween each infill pour strip and stressed,together with the additional multistrandtendons in the footing slab.Precast baffle walls were constructed on thepost-tensioned slab in eight separate castingbeds per tank cell. After the baffle walls were

TEAM &TECHNOLOGY

OWNER MelbourneWater Corporation

MAIN CONTRACTOR Tenix Alliance, Australia

DESIGNERJanine Ralev / Structural Systems Limited, Australia

TECHNOLOGYBBRVT CONA CMI internalBBR CONA flat


erected, the precast tie beams were installedand finally, all the pour strips were closed inand the sealing of the tank commenced.Our alternative post-tensioned design of theslabs and walls provided significant projectsavings – less concrete and traditional steelreinforcement, reduced labor requirementand fewer overall construction joints,resulting in lowered leakage risk and long-term maintenance issues. �

“INTERNAL SOFTWAREWAS DEVELOPED TOINCORPORATE ALL

THE POSSIBLE LOADCOMBINATIONS – IN SOMEINSTANCES, UP TO 40 LOADCASES WERE CONSIDERED...”

� Post-tensioned concrete slabs cast in situ

– with total area of 24,000 m2.The post-

tensioned slab was typically 200 mm

thick throughout and 500 mm thick

underneath the tank walls.

− BBR CONA flat system – five strands,15.2 mm diameter, stressed to 85%UTS

− BBRVT CONA CMI 1206 system –12 strands, 15.2 mm diameter,stressed to 80% UTS

� Post-tensioned concrete walls cast in situ

– approximately 2,200 linear meters of

wall, with thicknesses ranging from 450

mm to 550 mm, 6 m high.− BBRVT CONA CMI 0706 system –seven strands, 15.2 mm diameter,stressed to 80% UTS

� Concrete cells – each has four passes,

divided with precast baffle walls, 74 in

total, 180 mm thick, reinforced concrete.

� Grillage of walkways – achieved with 49

precast reinforced concrete tie beams

and insitu wall header beams as part of

the main post-tensioned wall design.

� Post-tensioned slab infills and reinforced

slab & wall infills – strategically located

every 50 m to control short and long

term creep and shrinkage movements, in

order to minimize the risk of sewage /

water leakage using standard

waterproofing sealants in the joints.

Alternative design solution

53CONNÆCT

The LNG is stored at -161 ºC in specialtanks suitable for such low temperatures.Security and resistance are the primarydesign considerations for the construction ofthis type of tank which must be designed towithstand earthquakes and strong winds.A very high quality control process must beapplied during construction – using only thevery best construction materials andtechnologies – because storage of a highlyinflammable product is involved.

NEW TANKSThe seventh and eighth LNG tanks inBarcelona are cylindrical concrete vesselsmade specifically for Liquefied Natural Gas(LNG) and are 80 m in external diameterand 41 m high. Construction of the twotanks is being carried out simultaneously –thus the project is a great constructionchallenge!In total, there are more than 600,000 kg ofpost-tensioning steel in each one – splitbetween vertical and horizontal tendons.Weused the BBRVT CONA CMI 1506, 1906and 2406 systems for the prestressing on thisproject.

INTERIOR POST-TENSIONINGThe interior prestressing consists of:� For the four foundation slab rings – 24 xBBRVT CONA CMI 2406 anchorages in140 m tendons

� For the horizontal wall – 280 x BBRVTCONA CMI 1506 anchorages in 130 mtendons

� For the vertical wall – 140 x loops withover 90 m in each and 280 x BBRVTCONA CMI 1906 anchorages.

Both the foundation slab rings and horizontaltendons are fitted with galvanized duct andthe inferior curves of the vertical loops aremade of galvanized duct too, but eight metersof 104 mm diameter stiff duct is connected tothe remainder of the vertical straight design.This connection is achieved by way of theexpanded end of the tube which permits rigidjoints to be formed between sections.

STRAND PUSHINGThe horizontal cables were pushed with thehelp of a strand pushing machine hung from acrane, while the operators were located on ahydraulic platform.The pushing machine wassecured by tying it to the tank to avoid any

jerky movements caused by the strandpushing process. Meanwhile, the vertical cableloops were pushed by means of a flexibleduct situated between the 1906 anchorageand the pushing machine.

STRESSING & GROUTINGThe foundation slab rings were stressedbefore the tank construction began andstressing of the other tendons was carried outduring construction because of the forcesapplied to the structure.The agreed sequence began with the stressingof some horizontal tendons, followed by thefirst half of the vertical loops. Next, half of thehorizontal tendons were stressed before thesecond half of the vertical tendons. Finally, thelowest horizontal cables, beside the accessdoors, were stressed.Having carried out a battery of inclined tubetests using our chosen cement grout, it wasapplied by the wringing method which resultsin the complete elimination of any possiblewater exudation at the top of the tendons.�

TANKS&SILOS

David Olivares Latorre, from Spanish BBR Network memberBBR PTE, reports that to meet the growing demand fornatural gas currently being experienced in the

metropolitan area of Barcelona, Enagas decided to build a furthertwo LNG storage tanks in the port of Barcelona.

TEAM &TECHNOLOGY

OWNER ENAGAS

MAIN CONTRACTORFCC Construcción, S.A. + F.I.

DESIGNER FCC Construcción, S.A. + F.I.


BBR NETWORK MEMBER BBR PTE (Spain)

SEVENTH & EIGHTH LNGTANKS, BARCELONA, SPAIN

54 CONNÆCT

As a result of our good working relationship –developed during construction of LPG tanks inAbu Dhabi – Chicago Bridge & Iron Company(CB&I) appointed us as the specialistsubcontractor for post-tensioning worksassociated with construction of the propylenestorage tank within the Borouge 2 Project inRuwais, Abu Dhabi. Meanwhile, our successfultrack record of LPG tank construction in AbuDhabi led to our appointment – by maincontractor A. P. Bawa – to undertake a similarscope of specialist post-tensioning works for theclinker silo being constructed as part of the BinaniCement Factory expansion at Jebel Ali IndustrialArea, Dubai.

PROPYLENE STORAGE TANKThe project included the construction of a23,000 m3 capacity propylene storage tank – witha 37.9 m internal diameter and concrete wallheight of 32.05 m – the wall was typically 0.5 mthick, tapering to 0.8 m over the bottom 6.5 m.The post-tensioned wall was constructed by usingconventional form shuttering and ten concretepours, each 3.25 m in height.Thirty two full circumference loop tendons, eachdivided into two semi-circular segments anchoredwith BBR anchorages – complying with thecryogenic (low temperature) requirements of theproject specification – were detailed to satisfy the

WarwickIronmonger,General

Manager for StructuralSystems’ operations inthe Middle East, andRavindra KumarChauhan, CivilOperations Manager forBBR Network memberNASA StructuralSystems LLC, providean overview thecompany’s involvementin recent tank and siloprojects in the MiddleEast.

long-term horizontal force profile dictated byCB&I.The strands were post-threaded into thetendon ducts after concreting with a high speedstrand pusher and using four buttresses toaccommodate the stressing of the tendons via550 t jacks.The overall tank design dictated that the stressingshould be carried out in three stages:� Stage 1 – three top-most tendons stressedbefore casting of tank roof.

� Stage 2 – 19 tendons stressed after casting oftank roof.

� Stage 3 – remaining ten (lowest) tendonsstressed after closing of two temporaryconstruction openings.

Mast-climber platforms were used effectively atthe buttress locations to provide access topushing, stressing and grouting work fronts – toensure the timely completion of prestressingactivities.

CLINKER SILOThe scheme was for the construction of oneclinker silo with an internal diameter of 40 m,concrete wall thickness of 0.4 m, a 24 m highconcrete wall and four stressing buttresses.Therewere 50 full circumference loop tendons, witheach tendon divided into two semi-circularsegments, with eight extra tendons positionedabove the dozer opening.

Relationships ...

TANK & SILO CONSTRUCTION, UNITED ARAB EMIRATES

55CONNÆCT

Round-the-clock work for duct installation,along with the slipforming of the walls,permitted the total wall height of 24 m to beachieved in only 12 days.The strands withinthe tendons were post-threaded afterconcreting by means of a specialist high-speed strand pusher.We used 200 t jacks which had been speciallyfabricated for the BBRVT CONA CMI 0706anchorage system, for the stressing operations.All tendons, except those terminating at ortrimming the dozer opening, were stressedfrom each end. Stressing activities for thisproject were successfully concluded within tenworking days.

SCOPE OF SERVICESWe were responsible for the supply of post-tensioning materials, shop drawings relatedto post-tensioning, designing of anti-burst andsplitting reinforcement, calculation of tendonextensions and friction losses, installation ofpost-tensioning materials, stressing andgrouting with our own specialist equipment,and associated QA / QC and engineeringsupport.

For the Borouge 2 propylene tank, our remitwas extended to include the completedesign of post-tensioning, based on the longterm prestress force profile provided byCB&I.

POST-TENSIONINGFor these projects, we used a total of:� 128 x BBR CONA internal 1906anchorages – with 10 to 18 strandoccupancy.

� 248 x BBRVT CONA CMI 0706anchorages with five strand occupancy.

� 11,000 m of 55 / 105 mm internaldiameter, 0.4 mm thick galvanized ironspiral ducting as per EN 524 / 523.

� 130 t, 0.6 inch diameter low relaxation PTstrand.

GROUTINGGrouting, both at Ruwais and Jebel Ali, wascarried out from ground level, with specialistgrout mixing and pumping units and followedon from successful grouting mock-upsconducted at site to check the occupancy ofgrout.

We look forward to the continuedapplication of our valuable experience intank and silo construction, gained throughsuccessful involvement in prestigious andchallenging projects throughout the MiddleEast region. �

TANKS&SILOS

... and reputation

TEAM &TECHNOLOGYBorouge 2 propylene storage tank

OWNER Abu Dhabi Polymer Company Limited

MAIN CONTRACTOR CBI Eastern Anstalt

CONSULTANT Tecnicas Reunidas


BBR NETWORK MEMBER NASA (BBR)Structural Systems LLC (United Arab Emirates)

Binani Cement clinker silo

OWNER Binani Cement Factory

MAIN CONTRACTORA. P. Bawa Construction LLC

CONSULTANT FLSmidth Designs PrivateLimited, India and Corporate Planners EngineeringConsultants, Dubai



“THEREWERE 50 FULLCIRCUMFERENCE LOOP

TENDONS,WITH EACHTENDON DIVIDED INTOTWO SEMI-CIRCULARSEGMENTS ..”

56 CONNÆCT

Photo courtesy of Axpo Holding AG.

57CONNÆCT

Since 1969, BBR has providedthe post-tensioning for 65nuclear facilities in 13

countries. Although the companyhas always conducted rigoroustesting of their tendons,inspections must be also made atregular intervals to ensuremaximum performance is beingachieved. During the 1970s, BBRNetwork member Spennteknikkcarried out the post-tensioningwork for eight nuclear powerplants in Sweden and Finland, formany of which they continue toinspect and maintain the post-tensioning installation.

The first four post-tensioning operations wereperformed with normal cement grouting, the nextthree, at Ringhals, were grouted with grease – andthe last one, at Forsmark, was protected bypumping dry air through ducts. Spennteknikksupplied and installed the post-tensioning systemfor all these nuclear power plants.The client required a high quality post-tensioningsystem and a corrosion protection system wasdesigned with both circulating dry air and greasegrouting. For Ringhals 2, 3 and 4, grease grout waschosen for corrosion protection. In order toensure the durability of the cables and forces, aninspection program is carried out at certainintervals.Owned by Vattenfall and E. ON Kärnkraft SverigeAB, Ringhals 2 is one of the nuclear reactors atRinghals – Sweden’s largest power plant – in thesouth-western part of Sweden. In total, there arefour reactors at Ringhals – three pressurizedwater reactors and one boiling water reactor. In anormal year, Ringhals generates some 28 billionkilowatt-hours of electricity.This is approximatelyone fifth of Sweden’s total electrical energyconsumption.The reactors are protected by an outerprotection shield constructed of prestressedconcrete – the walls are 600 mm thick.The post-tensioning system used was the BBRV 1396 mm prestressing wire system, grouted withgrease.The project consisted of inspecting the cables inthe outer shield, including replacement and testingof BBRV wire.Spennteknikk has a continous agreement withVattenfall for the inspection of the nuclear �

With over 60 years’ experience in thedesign and application of post-tensioningproducts, it will be no surprise to learnthat BBR tested their first high capacitytendons for nuclear power stations inthe 1960s.The BBRVT CONA CMI system fornuclear applications has securedEuropean Technical Approval ETA – andset a new world record in 2008 when a73-strand tendon was successfullytested to the Guidelines for EuropeanTechnical Approval ETAG 013.Three types of BBR post-tensioningtendons – all of which have securedEuropean Technical Approval – are

typically used for the inner containment:� Vertical tendons for wall post-tensioning

� Horizontally looped tendons or‘hoop’ tendons

� Horizontal end slab post-tensioning‘cane shaped’ tendons.

During the entire lifetime of thepressure vessels, the greatest attentionmust be paid to the protection of theprestressing steel from corrosion.TheBBR Network uses three different typesof corrosion protection for nucleartendons – cement grouting, grease orwax grouting and circulating dry air.

TANKS&SILOS

Technical insight:High capacity tendons

“THE CLIENT REQUIRED A HIGH QUALITY POST-TENSIONINGSYSTEM AND A CORROSION PROTECTION SYSTEMWAS

DESIGNEDWITH BOTH CIRCULATING DRY AIR AND GREASEGROUTING.”

RINGHALS 2,NUCLEAR POWER PLANT, SWEDEN

LNGTANK, STAVANGER,NORWAY

Secure cryogenicstorageAt the new LNG processing and storagefacility – created by energy provider LyseGass – Norwegian BBR Network memberSpennteknikk has installed the post-tensioning for a new 20,000 m3 tank.The plant is in Stavanger, south-westernNorway and, as well as the LNG tank, theproject included a process area and quay.Theproduction capacity of the plant will be300,000 t LNG per year.The LNG tank consists of an inner and anouter tank – the latter, a post-tensionedconcrete structure, will serve as a protectiveshield.The outer tank, with its 800 mm thick wall,was constructed by slipforming and we used75 t of strand to complete the post-tensioning. For the horizontal tendons, weused BBRVT CONA CMI 1906 and for thevertical loop cables BBRVT CONA CMI0706 tendons were installed. Standard metalducts were used for the PT cables, except forthe loops on the vertical cables. Prefabricatedthin-walled pipes were purpose made tosimplify the installation of strands.In addition, we provided cryogenic testreports – as required by the client – andthese were supplied by BBR Headquarters.�

58 CONNÆCT

power plants and Ringhals 3 will beexamined in 2010, along with Forsmark 3.Nuclear power plants are subject to astringent inspection programme andSpennteknikk is the natural partner forVattenfall for these projects.For the continuous safety of service oflarge tendons, accurate measurement ofthe stressing force and regular monitoringare of great importance.The inspection of the post-tensioningsystem includes monitoring of the stressingload for three roof cables, three verticalcables and six horizontal cables – allrandomly-selected. Also included is the de-stressing and replacement of one wire inthe roof cables and one horizontal cable –and, thus, stressing of these.The wire and the grease removed must betested and verified prior to acceptance ofthe inspection.To date, we haveencountered no failures of either thecables or the corrosion protection. Loss ofprestressing force, over the years, is nowabout 20% – which was as expected andthis will be adjusted during a completeinspection in 2011.Working in such restricted areas demandsspecially trained technicians, as well asspecial equipment. Security of personnel isstrictly controlled and our people mustalso have health inspections and specialHES education.Our work on nuclear power plants givesus a unique experience and know-how,the requirements fromVattenfall areinspiring and demanding at the same time– a driving force for our qualitymanagement. �

TEAM &TECHNOLOGY

OWNER Lyse Gass

MAIN CONTRACTOR Kruse Smith AS

CONSULTANT Norconsult AS


BBR NETWORK MEMBERSpennteknikk (Norway)

Nuclear inspectionprocedures

� Lift-off of the anchor head with theBBR automatic stressing device todetermine the actual prestressingforce – this is digitally recorded byan x-y-writer.

� The tendon is subsequentlyreleased and a single tensileelement is extracted for corrosionexamination and further testing inthe technical laboratory.

� A new single tensile element isinstalled and the tendon is stressedagain to its original prestressingforce

TEAM &TECHNOLOGY

OWNER Ringhals AB

MAIN CONTRACTORSpännteknik AB, Sweden

DESIGNER Vattenfall AB

TECHNOLOGY BBRV wire

BBR NETWORK MEMBERSpennteknikk (Norway)

59CONNÆCT

In 2010, BBR celebrates its golden anniversary in the staycable technology arena, while the BBR Network has some 66years at the leading edge of construction technology. For 50

years – and for over 400 projects – the BBR Network has beendelivering engineering excellence with state-of-the-artconstruction products. BBR VT CEO – Marcel Poser, takes us ona voyage through the history and development of stay cabletechnology, onto the latest thinking on the subject. So, relaxand enjoy the journey!

Goldenstrands

STAYCABLES

60 CONNÆCT

Cable-stayed bridgeshave been built inrapidly increasing

numbers since 1950 and havebeen found to be especiallysuitable for medium to long-span bridges from 100 to 1000meters, where technical andeconomic considerationsdictate a cable-stayed solution.

The idea of supporting a bridge deck withcables from one or two pylons has beenaround for a long time.The principle of cable-stayed bridges can betracked back to the early 1600s when theVenetian Faustus Verantius, best knownperhaps for his book Machinae Novae, built awooden bridge supported with chain stays.In 1784, the carpenter C. J. Löscher designeda cable-stayed bridge with an approximate32 m span length where the entire bridgewas made out of wood, including the stays.

EARLY ASSUMPTIONSIn the 19th century, the French engineerClaude-Louis Navier studied several bridgesystems supported by wrought iron chains.The results of his studies showed thatsuspension bridges should, in general, bepreferred over cable-stayed systems. Fromtoday’s point of view, it can be said – withcertainty – that the French engineer’s finalconclusions were wrong! However, at thetime Navier was studying these differentbridge systems, the knowledge and

11960 – BBR No.1

World’s first applicationof high amplitude fatigueresistant wire stay cablesat the Schillersteg inStuttgart, Germany.

THE 50 YEARS OF STAYCABLE EXPERIENCE WITHINTHE BBR NETWORKACROSS OVER 400EXECUTED STAY CABLEPROJECTS INCLUDES:

EvolutionTECHNOLOGY

STAYCABLES

61CONNÆCT

equipment for achieving even distribution ofthe load between all the cables – which isone of the key issues for cable-stayed bridges– were simply not available.

POST-WAR PIONEERINGGerman engineers led the design of cable-stayed bridges afterWorldWar II.TheGermans’ challenge was to find new,innovative and inexpensive bridge designs toreplace most of the Rhine river crossingswhich had been destroyed during the war.Civil and structural engineer, Franz Dischingerproposed systems where the central spanwas supported by a suspension system andstay cables carried the outer parts.Dischinger’s combined solutions were neveradopted for an actual bridge, but his studieshad a huge influence on the development ofthe true cable-stayed bridge system. It was,however, not until the 1950s that Dischingerdesigned the first true cable-stayed bridge –the Strömsund Bridge in Sweden which hada main span of 183 m and two side spans of74.7 m.The Germans further developed the designof cable-stayed bridges in the following

decades and built several of them.The seriesof bridges near Duisburg across the RiverRhine are examples of these pioneeringGerman bridges.In Cable Supported Bridges: Concept andDesign, Niels Gimsing attributes the increasein cable-stayed bridge designs to theimproved structural analysis tools that wereavailable.

FIRST FOR BBRWhile many cable suppliers built their firstmajor cable supported structure in the late1970s and early 1980s, BBR Stay CableTechnology was used for the first time in thelate 1950s and, since those days, BBR hasfollowed on with milestone-after-milestone –and today continues to set the standard inthe field of stay cables. �

1972 – BBR No.5

World’s firstapplication of strandstay cables at theOlympic Stadium inMunich, Germany.

1978 – BBR No.25

World’s first cable-netsupported tower atCenterpoint in Sydney,Australia.

Dischinger’s Strömsund Bridge in Sweden is celebrated as the first true cable-stayed bridge.

Löscher’s 1784 design for a cable-stayed bridge.

30

62 CONNÆCT

Cable-stayed structureshave a great potentialwhen it comes to

meeting the increasing demandfor long span structures.Theyoffer increased aerodynamicstability and reduced costs forthe abutments,with faster, easierconstruction and light overallstructures.However, the mostimportant factor in ensuringdurability and performance of acable-stayed structure will alwaysbe the stay cable system.

Durable and efficient structures require highstrength, high amplitude fatigue resistant,redundant and durable stay cable technology.In the past, many cable systems have beenused, such as locked-coil, wire ropes andbars.By today’s standards, these technologiesno longer fulfill the requirements of highcapacity structural applications.

WIRE STAY CABLESThe first stay cable technology to provide therequired static strength and high amplitudefatigue resistance was parallel wire cables.Theanchorage system generally consisted ofbutton heads, on the individual wires, whichtransfer the load into an anchor head and intothe supporting bearing plate.The usage of full or partial bond type socketanchorages, in combination with button headson the individual wires, is a furtherdevelopment and is widely used.The firstapplication of such high amplitude fatigueresistant wire cables was in the late 1950s onthe Schillersteg in Germany.Today, wire stay cables are made up of apredetermined number of parallel or semi-parallel individually galvanized wires of lowrelaxation grade steel and a minimumguaranteed ultimate tensile stress (GUTS) of1670 MPa or 1770 MPa.These are enclosedin an ultraviolet (UV) resistant high-densitypolyethylene (HDPE) stay pipe or sleeve ofcircular cross-section and the voids betweenthe individual wires and the HDPE sheathing

are filled with a corrosion inhibitor.Theanchorages used are, in most cases, still basedon the button head invented back in the1950s.

STRAND STAY CABLESHigh amplitude fatigue resistant strand staysfound their first major application on theOlympic Stadium in Munich, Germany, withits cable supported membrane roofstructure. Munich hosted the Games in 1972

311981 – BBR No.36 & 374!

Sloboda Bridge in Novi Sad Serbia, which was originally opened totraffic in 1981, destroyed during NATO bombing in 1999, subsequentlyreconstructed and reopened to traffic in 2005.The Sloboda Bridge isthe world’s first cable-stayed bridge which was built twice and theworld’s largest cable-stayed bridge reconstruction project

Fulfilling thepotential

World first for carbon staysThe Storchenbridge inWintherthur(Switzerland), crossing the major east-to-west axis of the Swiss Federal RailwayNetwork, was the world’s first bridge usingcarbon stay cable technology. Due to itslow self-weight, carbon stay cables are apromising solution for ultra long spanbridges.Their extremely high fatigueresistance and the fact that carbon is non-corrosive are further advantages of thistype of cable.

63CONNÆCT

and the stadium became the home ofBayern Munich, one of the world’s premiersoccer clubs.Strand stay cable configurations aretraditionally anchored by means of wedges,which bite into the strand and transfer theload into an anchor head and the supportingbearing plate. Epoxy and bond typeanchorages have also been used in the past.Modern strand stay cables are generallymade up of a predetermined number ofparallel low relaxation grade steel strandswith minimum GUTS of 1770 MPa to 1860MPa enclosed in an UV resistant HDPE staypipe of circular cross-section.The strands aregalvanized, greased or waxed and individuallysheathed with a continuous and wear-resistant HDPE coating, providing each strandwith a triple protection system.

SELECTION FACTORSWire stay cables are generally prefabricatedand strand stay cables are more commonlyassembled on site using a strand-by-strandinstallation method, thus the choice of thesuitable cable system for a particular projectdepends on many factors.It is often considered that prefabricatedcables are best suited to smaller bridges. Onsite fabricated stay cables are usually suitedto longer spans. However, the designertogether with the specialist stay cablecompany must evaluate each projectindividually. Erection requirements, as well asthe overall economics, should always beconsidered.

SOLUTIONS OF CHOICEBoth wire and strand type cable systems aretoday’s solutions of choice for modern cablestayed structures. Over the years, theultimate tensile strength of the wires andstrands has gradually been increased and willfurther be increased. Furthermore, thecorrosion protection systems have beenenhanced.To enhance the long termdurability of the stay cables, the uses ofepoxy coated strands might be alternativesfor the future. �

STAYCABLES

1987 – BBR No.79

ALRT Skybridge, the world’slongest transit skytrain-onlybridge, spans the Fraser Riverbetween NewWestminster andSurrey, Canada, built.Photograph courtesy of MacPhotogrammetry/Flickr 100

Wire Stay Cables� Fabricated to a pre-determinedlength with length adjustability atthe anchorages, requirestransportation and heavy liftingequipment on site.The pre-fabrication results in a very shorterection time on site.

� The cable diameter is morecompact which has a series ofaerodynamic advantages for verylong cables.

� The fatigue resistance is generallyhigher.

Strand Stay Cables� More labor-intensive on site, butrequires only limited capacitylifting equipment.

� Requires a larger stay pipediameter, which can influence theaerodynamic behavior.

� Replacement of single tensileelements is easier.

System selection factors

WIRE STAY CABLE

STRAND STAY CABLE

Draubridge, Ptuj, Slovenia (2007) – BBR cable-stayed structure Number 391

HDPE Stay Pipe(coextruded if required)

HDPE Stay Pipe(coextruded if required)

HDPE Coating

Corrosion Inhibitor

Corrosion Inhibitor(optional)

Strand 0.62" (15.7mm)UTS 1770 - 1'860 MPa

CorrosionInhibitor

Galvanized

Galvanized

7mmWireGUTS 1'670 - 1'770 MPa

64 CONNÆCT

Calatrava, has become one of the mostcelebrated features of the City. One of hislatest designs, the new Serrería Bridge, nowrises in the centre of this stunning complexto a height of 126 m – making it the highestpoint of the City.

THE WAY AHEADEven as this edition of CONNAECT goes toprint, construction is underway on one ofour next 400 cable-stayed structures – theSava Bridge on the Belgrade Inner CitySemi-Ring Road in Serbia.With its 200 mhigh pylon and 376 m main span, the bridgewill have the second longest stay cables inEurope – and is set to become a significantlandmark for the city and for the future ofthe BBR Network. �

1011996 – BBR No.197

World’s first applicationof carbon stay cables forthe Storchenbridge inWinterthur Switzerlandin 1996.

Whether for transportation, energy,communications or sporting infrastructure,the BBR Network has delivered a wealth ofenduring and magnificent cable-stayedstructures around the world.

THE AMERICASWhile cable-stayed bridges are extremelypopular in Europe and Asia, they are really juststarting to catch on in North and SouthAmerica. Recently, in Boston, Massachusetts, acable-stayed design was selected for a newbridge across the Charles River, even thoughcheaper options were proposed. Maybe it isan irony that, in the otherwise public trans-port-shy North America, the 616 m SkybridgeinVancouver is the longest cable-supportedtransit train-only bridge in the world.

ASIA / PACIFICCable-stayed bridges are extremely popularin many Asian countries for helping toresolve traffic congestion and to improve theinfrastructure of the incredibly fast growingmetropolitan areas. Japan probably has thehighest density of cable-stayed bridges.Among the booming countries nowadays isChina, where a series of future world recordspan bridges are currently underconstruction.Cable-supported structures in Asia have alsobeen defined as purely architectural andlandmark structures and are often built tocommemorate former or present kings andrulers, such as the RAMAVIII Bridge inThailand.Wedge anchored strand stay cablesand compact stay pipes have been utilized inthis bridge which is one of the world’slargest single pylon bridges.

The longest cable-stayed bridge built in the20th century, the Tatara Bridge in Japan, hasa breathtaking total length of 1480 m and apylon height of almost 240 m.The first majorapplication of stay cables in Australia was inthe unique supporting net structurecomposed of parallel wire stay cables forthe stabilization of the 230 m Centre PointTower in Sydney, constructed in the 1970s.Environmental campaigners had little tocomplain about when the aptly named800 m long Green Bridge in Brisbane wasconstructed. It is Australia’s second-longestcable-stayed bridge, after the ANZACBridge Sydney, and is entirely dedicated topublic transport, cyclists and pedestrians.

EUROPEThe mother continent of cable-stayedbridges and structures is Europe, with thefirst major applications taking place in thelate 1950s.Aesthetic qualities are also important on theEuropean continent and this is admirablydemonstrated by the scenic SunnibergBridge in the skiing resort of Klosters, in theSwiss Alps, which was designed by thelegendary Swiss Engineer Christian Mennand was opened to traffic in 2005 by PrinceCharles.This masterpiece of engineering,which fuses perfectly with the scenicsurroundings, employs a button head typewire stay cable system. Characterized by itsshort pylons and shallow angle stays, itexhibits the essence of a technical andaesthetic solution in a prominent landmark.In the south of Valencia, the City of Arts &Sciences designed by the internationallyrenowned architect and engineer Santiago

In 50 years of stay cable experience, the BBR Network hascarried out over 400 stay cable projects – notching up anumber of ‘world firsts’ and establishing its position at the

forefront of this technology along the way.

Around the world ...

65CONNÆCT

STAYCABLES

1997 – BBR No.234

Longest cable-stayedbridge built in the 20thcentury – the TataraBridge in Japan.

2000 – BBR No.286

World’s first combinedarch and stay cablebridge – the SeriSaujana Bridge (BR8) atPutrajaya in Malaysia. 300

RAMAVIII Bridge,Thailand (2002)- BBR cable-stayed structure Number 325

... creating international iconsSunniberg Bridge, Switzerland (1997/2005)– BBR cable-stayed structure Number 232

Green Bridge / Eleanor Schonell Bridge, Australia (2006)– BBR cable-stayed structure Number 387

Sava Bridge, Serbia (2012)- one of the next 400 BBR cable-stayed structures

66 CONNÆCT

Up to 2008, the four major players executingstrand and wire stay cable projects inter-nationally, had completed some 800 projectsworldwide – ranging from 70 to 400 perplayer.Their first projects were undertakensomewhere between 1960 and 1985 andthus the long term experience with such staycables covers a range of between 25 and 50years, depending on the individual company.At first sight, this long-term experienceappears considerable – but after analyzingavailable data, it becomes clear that around40% of the projects are not more than 10years old. Meanwhile, BBR has the most

projects (400) and the oldest references (50years). Only 5% of the projects are more than30 years old and the average age of all execu-ted projects is 14 years. If the reference dataof all players were considered, the average ageof the structures would even be younger.So, it is not surprising that there are onlyvery limited known major problemsreported on cable stayed bridges, as theaverage cable supported structure is stillextremely young compared to theirexpected life of 100 years. Most structuresare nowhere near their critical fatigue life andother ageing effects are not yet visible.

ELIMINATING RISKAmongst the reported problems worldwideare corrosion on the cables, corrosion andleakage at the anchorages, fretting fatigue,damage of the cables and cable vibrations.Corrosion protectionTargeting a 100-year life requires a high levelof corrosion protection for the cables –making directly exposed cable surfaces suchas locked coil and bar cables obsolete foranything other than architectural applications.Additional considerations should be given tothe replaceability of the key components.LeakagesLeakages observed at the anchorages havebeen addressed by specific leak tightnesstests, whereas the leak tightness test, as perfib specifications, is the most suitable one andsuccessful completion of the specific leaktightness test is mandatory.Prohibit groutGiven today’s increased life expectation of100 years for stay cables, the usage of groutin contact with bare or galvanized singletensile elements in the free length of thecable, over a sadle or as a bonding agent forload transfer at the anchorage should beprohibited because of:� possible interaction of grout withgalvanized single tensile elements, whichmay lead to hydrogen brittleness

� the poor long-term corrosion protectiondue to the natural cracking of the groutunder the cyclic loading on the staysrepetitively reported fretting fatigueobserved especially on strands emendedin conventional grout

� the fact that grouted stays are hardly re-tensionable

Costly special epoxy grouts and perfectinjection techniques on site have shownsatisfactory results for wire stays in the past– 50-year old grouted stays are still inservice. However, given today’s demand forindependent multi-level corrosion protection– for forgiveness during installation and long-term redundancy – grout should not be usedin direct contact with the strands or wires.Specialist repairsEarly repairs of cables that have been

3012002 – BBR No.325

RAMAVIII Bridge in Bankok,Thailand,completed in 2002 and featured on the 20-baht banknote.With a 300 m main span, thebridge is also one of the world’s longestsingle pylon cable stayed bridges

Only in recent decades, have actual definitions in terms ofexpected design life of a structures been given. In theearly days, a 20-year life was considered suitable,

however today, a 100-year design life is state-of-the-art – and thisis, for example reflected in the formal European Approval Testingof post-tensioning kits under ETAG 013.

Planning forlongevity

67CONNÆCT

damaged during installation, accidents orcable vibrations events should be con-tractedto specialist stay cable companies.Installation specialistsAn important lesson learned on strand as

well as wire stay cables – especially byowners and contractors – is that cableinstallation is the work of the specialist whoalso provides the stay cable technology.Practices of the past, where only supply of

STAYCABLES

4002008 – BBR No.400

Most recent international landmarkstructure, the recently openedSerreria Bridge in Valencia in 2008,designed by engineer and architectSantiago Calatrava.

fully or partially prefabricated stay cables hasbeen contracted to the system suppliersmust be avoided.Cable vibrationEven newly constructed cable stayed bridgeshave experienced quite severe vibrationswhich may result in failures of cables. Acareful evaluation is therefore alwaysrequired and countermeasures, such asdampers are highly recommended.Design of long cablesCare should also be taken when designinglong cables. Effects, such as the sag of thecable on the effective damping, rotationalbending stresses and other effects can onlybe appreciated for long cables.

CONTINUOUS IMPROVEMENTTo achieve the desired 100-year design life,detailed consideration of all aspects is crucialand stay cable specialist companies, such asthe BBR Network, must continue to developand promote use of the latest technologyand expertise in its deployment. �

Ormiston Road Bridge, New Zealand’sfirst (2008), Number 393

68 CONNÆCT

STAYCABLES

69CONNÆCT

RECENT TESTINGImpressive evidence of the leading role ofBBR in relation to testing are the testsexecuted successfully, over the past 24months, on the BBR HiAm CONA strandstay cable system:� Axial fatigue and subsequent tensile testaccording to fib, with a stress range of200 MPa and angular shims of 0.6degrees at the anchorages on varioussmall, medium and large tendons sizes.

� Static as well as axial fatigue andsubsequent tensile test according to fibon the BBR HiAm CONA pin connector.

� Axial fatigue and subsequent tensile testaccording to SETRA, with a stress rangeof 200 MPa and an angular rotation of0.6 degrees at the anchorages on amonstrous 127 strand BBR HiAmCONA cable.

� Axial fatigue and subsequent tensile testaccording to SETRA for extradosedapplications using saddles with a stressrange of 140 MPa and an upper load of55%.

� Leak tightness test according to fib withaxial, rotational and temperature cycles,while BBR HiAm CONA is the onlysystem where the sealing can bereplaced on an individual basis as part ofsingle strand replacement operations.

GOING THE EXTRA MILEThe leading position of BBR is particularlyhighlighted by the tests, recently executed,with parameters exceeding the traditionalrequirements of fib and PTI.The following isa selection of benchmark tests carried outsuccessfully on the BBR HiAm CONAsystem:� Axial fatigue and subsequent tensiletests with upper loads and stress rangesexceed the commonly specified 200MPa stress range and 45% upper load. Insuch fatigue tests, we achieved a 300MPa fatigue resistance and 55% upperload.

� Bending fatigue test with applied rotationsat the anchorages of 1.2 and 2.8 degreesfor 2.0 million and 0.2 million respectively.

� BBR Square Damper efficiency test withcable tensions ranging from 25% to 45%in 1st to 5th modes, on a BBR HiAmCONA stay cable model representing a450 m cable length.This test is especiallynoteworthy as cables of this length withlow tension experience second ordereffects due to large sag, which makesmany common dampers ineffective – notso the BBR Square Damper.

� Multi-million cycle wear and durability teston BBR Square Damper, proving theendurance and minimal maintenancerequirements of this advanced damper.

Obviously, the tests have been executed withstrands of the highest tensile resistanceavailable on the market – strands with aresistance of 1860 MPa with a cross sectionof 150 mm2 and a breaking strength of279 kN. Many stay cable suppliers still workwith strands of 1770 MPa capacities or

cross-sections of 140 mm2. Compliance testsfor such lower capacity strands have naturallyalso been executed on the BBR HiAmCONA system.Tests in the pipeline are a series of 10 millionload cycle tests with stringent parameterscompared to fib and PTI requirements.Tenmillion load cycle testing may be relevant forthe future application of stay cables forsupporting wind turbine towers. �

BBR stay cable systems are the benchmark in terms of testperformance and BBR stay cable technology has regularlyfulfilled higher testing and performance criteria – even

years before such testing conditions have been adopted andspecified in codes and recommendations.

Benchmark forTEST PERFORMANCE

70 CONNÆCT

Grand spectacle

71CONNÆCT

The Zagreb Arena is an enterprise of major dimensions and ona grand scale – it is a public building the like of which has notbeen built in Zagreb, or indeed Croatia, for decades. Months

before completion, the Zagreb Arena had already become one ofthe landmarks of the city.BBR Adria proudly reports on theircrucial contribution to the Arena’s striking external appearance.

World Men’s Handball Championship washeld by the Croatian Government and theCity Government of Zagreb.They selected a consortium comprised ofproperty developers – TriGránit (Hungary)– and Ingra (Croatia) who, in turn, engagedstudio UPI-2M from Zagreb, to create andproduce a unique design for the ZagrebArena.The construction of the sports hallstarted in July 2007 and was completed, asplanned, in December 2008.

BUILDING VISIONDuring the schematic design stage, thedevelopment of spatial and functionalcharacteristics – to enable maximum

flexibility of the venue – was vital.Thestructure is closed inwards, in the form of ashell, which reduces the span and, to adegree, provides cover for the area.The roof structure – reminiscent of thestructure of a suspension bridge – enablesthe slender 45 cm roof structure to cover aspan of 110 m. In a way, the roof is floatingover the hall. Cables and bars expand andcontract with shifting temperatures, thus theposition of the roof changes – togetherwith whatever is suspended from it. Inaddition, over the years there will bedeformation in the ribs, therefore, the roofis very flexible and getting it into the rightgeometric position was a challenging task.�

THE ZAGREB ARENA, CROATIA

Zagreb Arena is located in thesouthwestern part of Zagreb and the sitewill also include the Arena Center –expected to be the largest shopping-entertainment center in the city.Together,they will share a series of services such as ajoint parking lot, multiplex cinema, wellnesscenter, numerous restaurants, cafes andstores. BBR Adria will also have aconsiderable role in the building of theArena Center, which will certainly bereported in the next edition of CONNAECT.

PROJECT LAUNCHA public tender for the construction of a15,000-seat stadium to host the 2009

SPECIALAPPLICATIONS

72 CONNÆCT

SMOOTH SEQUENCINGResembling a giant rib cage around thebuilding, 86 large curved concrete columns–lamellas – form the main façade andsupport the roof structure and the semi-translucent polycarbonate building envelopewhich allows various illumination effects tobe used. BBR Adria prestressed all thelamellas using the BBRVT CONA CMIsystem.We installed 214 t of strand, togetherwith 680 anchorages.Within six months, the columns had beenprefabricated on site, lifted with a crane,vertically rotated through 90 degrees, trans-ported and fixed on the structure. Prestress-ing enabled all these maneuvers of the heavylamellas to be performed without any add-itional temporary reinforcement – and justthree or four days after casting the concrete.After the ring of columns was completed, wemoved onto the second part of our contractwhich was for embedding and stressing themain cables.The architectural cables are 100– 125 m long, 66 mm in diameter and eachhas a characteristic resistance of 2,636 kN.They carry the 2,000 t heavy structure madeof double-T profiles, together with 300 t of

auxiliary structures and equipment.Thisturned out to be a very delicate job – andmore complicated than originally perceived.In the third stage of our work, 567 bartendons were connected to the main cableswhich were awaiting connection to the roof.Vertical bars were connected first, as theywere designed to carry the roof. At the very

end of roof suspension operations, diagonalbars were added to provide lateral stiffness.Next, we embedded and installed 34 staycables – both vertical and diagonal – whichwere designed to give stiffness in aperpendicular direction.Finally, after all the stages of suspended roofconstruction which lasted for five months,the roof could be adjusted and also somesmall errors fixed.Then the Arena wasweathertight and ready for the final works –façade, auxiliary structure connected to theroof, ventilation, air conditioning, lighting,telescopic stands, visual identities, pavements,security, acoustics, sound and sportequipment.There were often aroundthousand people on the site.That’s not the end of our involvement herethough – with a requirement for regularmaintenance of the main cables andconnecting bars, together with periodicadjustments to the entire roof, additionalwork for BBR Adria is assured in the future.

Facts and figuresArena volume 367,054 m3

Arena area 27,337 m2

Span of suspended 103.6 mroof construction

Height of facade rib 28-37 m

Concrete volume 95,000 m3

Reinforcement quantity 9,500 t

Weight of façade ribs 160-220 t

Weight of roof structure 2,000 t

“Complete co-operation – BBR Adria was perfect. Experts onthe site were always available, excellent communicators, theyrespected and executed decisions and agreements and even

worked on Sundays and holidays without any objection. My onlysuggestion to BBR Adria is that they should never again say theyare small company – because they are great.”

Tomislav Sindler,Ingra, co-ordinator for Arena roof construction

73CONNÆCT

JUNGLE ACTIONImagine a jungle of ten rotating tower cranes,four giant caterpillar cranes manipulatinglamellas and stretching heavy main cablesacross the site, numerous machines, vehiclesand personnel, working like ants around theclock ... and all the co-ordination and logisticsrequired!But that was not all, our Arena project wasgrowing up under the watchful eye of bothCity authorities and the general public,particularly as the Championship openingceremony drew nearer – this imposed further,unnecessary, pressure on everyone involved.In fact, from the drawing board to the openingceremony, the Zagreb Arena project was anextraordinary challenge. One could have sat

on the upper stand of the unfinished Arena allday – with popcorn and cola – enjoying theshow, like some great action movie with ahappy ending!A few months after the project had beencompleted, the customer satisfaction formreturned from our client and surprised us a bit– we received straight ‘A’s’ for all aspects ofour collaboration and work on this project.Meanwhile, following the Championships, theArena is now being used for numerous kindsof sports and competitions – together withvarious concerts, exhibitions, fairs,conventions and congresses.The simple, elegant and efficient structuralconcept of the Zagreb Arena was recognizedat theWorld Architecture Festival in

Barcelona (4-6 November 2009), where itwas declared the outright winner in the2009 structural design category.The externalinward leaning ribs, braced by a ring beam,supported the suspended roof – and thepre-stressed prefabricated columns were ahuge undertaking in their own right. �

SPECIALAPPLICATIONS

TEAM &TECHNOLOGY

OWNER City of Zagreb

MAIN CONTRACTOR Ingra

DESIGNER UPI–2M

TECHNOLOGY BBRVT CONA CMI internalArchitectural Cable Bar

BBR NETWORK MEMBERBBR Adria d.o.o. (Croatia)

74 CONNÆCT

The Alan MacDiarmidBuilding at VictoriaUniversity’s Kelburn

Campus is New Zealand’s firstmulti-storey unbonded post-tensioned precast concretebuilding – and represents somenational and world firstapplications of PRESSStechnology. Bojan Radosavljevicpresents a report andcomments on BBR Contech’scontributions to this excitingnew technology.

The technology is significant because it hasrevolutionized design in earthquake engineer-ing and has done so by introducing advancedtechnical solutions for seismic-resistant precast/ prestressed concrete buildings. At the heartof this innovative approach are jointed ductileconnections – or PRESSS (PREcast SeismicStructural System)Technology – and thesystem was developed in the USA.In a ‘dry’ jointed ductile solution, precastelements are jointed together by unbondedpost-tensioning tendons or bars.The inelasticdemand is accommodated with a ‘controlled

rocking’ motion of the connection itself.Protection of the rocking interface means asignificantly reduced level of damage can beachieved. Moreover, the self-centering fromthe unbonded tendons can bring the buildingback to its vertical position with nopermanent / residual displacement.All typical advantages of off site prefabrication(quality control, speed of erection) andprestressed elements (long span, open spaces)are also maintained.Unbonded post-tensioning divides the

building’s seismic actions into ‘spring’ and‘shock-absorber’ mechanisms.This deliversadvantages over conventional structures:� The building is very stiff until the springsbegin to yield at which time they becomevery soft.

� The springs return the building to verticaleven after extreme earthquakes.

� The shock absorbers can be detailed to beremovable, further reducing the whole oflife cost of structural rehabilitation in highseismic areas.

Unbonded post-tensioning provides the springaction.The joints – between beams andcolumns and the shear walls at the ground –rock.The post-tensioning acts to clamp thesejoints closed and hence spring the buildingback to vertical.The shock absorbers – in thiscase, controlled yielding reinforcing bars –provide damping.Victoria University recognized the long termbenefits of this construction technology at anearly stage and also understood the need forclose collaboration and a capable design andconstruction team.There were careful checksand balances throughout the design andconsenting process. Key members of the teamincluded:� Victoria University ofWellington – IanMaskell,VUW Project Manager

Seismic resistant innovationALAN MACDIARMID BUILDING,VICTORIA UNIVERSITY,WELLINGTON, NEW ZEALAND

75CONNÆCT

� DunningThornton Consulting Limited –principal designer

� Stefano Pampanin, University ofCanterbury / PRESSS Ltd – peer reviewer

� BECA Consultants – advisor toWellingtonCity Council as consenting authority

� Mainzeal Property and Construction Ltd –Head Contractor.

In addition to this, any identified concernswere offset by agreeing that a high-leveloverview would be conducted by Nigel

Priestley, who was involved in much of thepioneering research in California as a co-ordinator of the PRESSS Program.The building comprises four suspended floorsof science teaching and research space builtover a flexible lower entry area used forteaching and conferences.The post-tensioning requirements for this typeof structure were developed to be relativelygeneric and BBR Contech was appointed tocomplete the works using the BBR CONApost-tensioning system.The building comprises six three-bay concreteframes carrying double-tees spanning 9.9 m.The frames span 8.4 m and because itsmembers are post-tensioned, sizes were keptto 0.60 m by 0.45 m for the beams and0.60 m by 0.55 m for the columns.The beamswere pre-tensioned off-site for gravity loadsand to minimize dead load / erection sag, thenthey were centrally post-tensioned throughthe columns using BBR CONA unbondedtendons to provide the rocking / re-centeringmechanism.There are a total of 21 beam lines containingpost-tensioning in the building, each with acentral BBR CONA unbonded tendonapproximately 25 m long and ranging in sizefrom 0505 -1505.The external columns arealso vertically post-tensioned, each with twoBBR CONA unbonded 0205 tendons toresist overturning loads and to assist with therocking mechanism and recentering capabilityat their base.

Energy dissipation is provided by externaldevices which are bolted to the pre-castbeams and columns.This allows these ‘plug-and-play’ devices to be replaceable after amajor event.In the longitudinal direction, the building isbraced by four 3.08 m x 0.4 m shear walls.These walls were coupled into pairs by three0.61 m deep steel beams to provide thehysteretic energy absorption.The advantagesof coupled rocking / post-tensioned walls havebeen extensively proven.In this case, the two mechanisms of thesehybrid systems are separated – the energydissipation is provided by flexural yielding ofthe steel coupling beams, while the re-centering is given by the rocking motion atthe base and the top of the shear walls.Thislowers the stress on each respective joint andso allows simpler detailing. BBR Contechsupplied and tensioned the 75 mm diameterbars used for the vertical post-tensioning.An innovative feature is the incorporation of acapping wall across each pair of shear wallswhich allows them to rock, both at the baseand at their top, for the same amount ofvertical post-tensioning.As with any ‘first’, this project involvedextensive attention to detail – in analysis,design and understanding assembly – far inexcess of conventional buildings.The capabilityand collaboration of all parties associated withthe project is a testament to its success.Any current price differential between PRESSStechnology and conventional constructionsystems will close over time, as the range ofadvantages offered by PRESSS are recognizedand quantified within life-cycle project costanalyses. �

SPECIALAPPLICATIONS

Supreme winnerThe excellence of the Allan MacDiarmid Building– as well as the teamwork and technologyinvolved in its realization – was recognized at the2009 Concrete Awards ceremony held by theNew Zealand Concrete Society.The project wasdeclared the winner in the Technology category,then voted SupremeWinner of all the categoriesand presented with the 2009 Concrete Award.Pictured here is New Zealand Concrete SocietyPresident Dene Cook presenting the supreme2009 Concrete Award to Alistair Cattanach ofDunning Thornton Consultants who accepted theaward on behalf of the entire project team.It was a particularly successful evening for BBR Contech, as their work on the FordBuilding and Ormiston Road Bridge was also recognized.

TEAM &TECHNOLOGY

OWNER Victoria University ofWellington

MAIN CONTRACTORMainzeal Property and Construction Ltd

ARCHITECT Jasmax

STRUCTURAL ENGINEERDunning Thornton Consultants

PRESSS REVIEWERStefano Pampanin / Nigel Priestly

TECHNOLOGY BBR CONA unbonded

BBR NETWORK MEMBERBBR Contech (New Zealand)

BBR Contech would like to acknowledge Alistair Cattanach,Director, DunningThornton Consulting Limited,Wellington;Stefano Pampanin, Senior Lecturer, University ofCanterbury, PRESSS Limited, Christchurch; MainzealProperty and Construction Ltd; andVictoria University ofWellington in the preparation and publication of thisarticle.The permission to use content from a similar articlepublished byThe Cement & Concrete Association of NewZealand is also acknowledged.

76 CONNÆCT

The Temple of God Providence in Warsaw willbe one of a kind.The structure is a huge

cross on plan with a temple inside.The top of thedome will be around 50 m above ground level.BBR Polska has supplied the specialist heavylifting know-how for this unique project.The four sides of the cross are formed by the fourso-called ‘bridges’ which join four huge pylons.The‘bridges’ were made at ground level and then liftedto their final location at the top of the pylons.The weight of the ‘bridge’ is 780 t and the liftingheight was about 26 m.The minimal distancebetween the ‘bridge’ and the pylon wall during thelifting operation was approximately 30 mm –therefore we had to take special care whenoperating the jacks. For this operation, we used afour jack lifting system.BBR Polska’s scope of work included conceptdevelopment, general and detailed design of thelifting operation, including structures for supportingthe jacks and working platforms, in collaborationwith structural designers SDS Sp. z o.o., andexecuting four complex lifting operations. �

The international cricket stadiumconstruction project was initiated by theNerul-based DY Patil Sports Academywhich is part of the DY Patil EducationSociety.The stadium boasts all facilities associatedwith an international cricket stadiumcapable of seating 60,000 spectators.Thestadium also has additional sports facilities– including five outdoor tennis courts,two indoor badminton courts, threesquash courts and an Olympic-sizedswimming pool. However, the mostprominent feature of the new stadium isthe cantilever roof which gives spectatorsa clear, uninterrupted view of match play.Main structural consultant, Eco DesignIndia (P) Ltd, invited us to design a post-tensioned solution which would achievelarge spans with a shallow beam depth togive sufficient headroom to allow clearsightlines for spectators all around the

stadium, as required by both the clientand architect.The brief also called for alighter structure through increased gridspans and reduced steel sections – as wellas cost savings.

GENERAL DESIGN ASPECTSThis cricket stadium, designed by a leadingarchitectural practice – Architect HaffezContractor – features a cantilever roofsupported by curved post-tensionedconcrete beams, at Levels 3 and 4, aroundthe whole circumference of the building.Level 3 and Level 4 consist of two beamsof 60.20 m span in the Media Center andsix beams of 53.20 m span in thecantilever roof area, with continuoussupport between the seismic joints.Toallow stressing operations to proceedwithout hindrance, a five meter longblister was designed at the continuoussupport location.TEAM &TECHNOLOGY

OWNER / OPERATOR Diocese ofWarsaw

MAIN CONTRACTOR Warbud S.A.

DESIGNERBBR Polska Sp. z o.o. and SDS Sp. z o.o.

TECHNOLOGY Heavy lifting

BBR NETWORK MEMBERBBR Polska Sp. z o.o. (Poland)

Heavenly lifting

TEMPLE OF GOD PROVIDENCE,WARSAW, POLAND For the first time, long span curved cast in-situ post-

tensioned beams have been adopted for a cricketstadium in India. Mr Virendra Hukum Singh and Mr

Manjunath from BBR (India) Pvt. Ltd jointly report on thecompany’s work to design, supply and install a post-tensioning system to eliminate roof supports – resulting in anunobstructed view of cricket matches for spectators.

FIRSTFOR INDIAN CRICKET

DY PATIL CRICKET STADIUM, NERUL, NAVI MUMBAI,MAHARASTRA, INDIA

77CONNÆCT

On Level 3, the post-tensioned beams for theMedia Center consist of four BBR CONAinternal 1905 tendons to the left and twotendons to the right of the continuoussupport, with a stressing end at a blister eitherside.The continuous post-tensioned beams forthe cantilever roof consist of four BBR CONAinternal 1905 tendons to the left and right ofthe continuous support, with a stressing endat a blister on either side.At Level 4, the Media Center post-tensionedbeams consist of two BBR CONA internal1205 tendons on the left and four tendons onthe right side of the continuous support, witha stressing end at a blister on either side.Meanwhile, for the cantilever roof, thecontinuous post-tensioned beams consist offour BBR CONA internal 1205 tendons onthe left and right of the continuous support,with a stressing end at a blister on either side.The uniform post-tensioned beam size of750 mm width and 2,500 mm depth was de-signed for beams in both Level 3 and Level 4.

The concrete grade adopted was 40 MPa at28 days and 32 MPa at transfer of prestressingforce to tendons. A total of 64 t of 12.70 mmLRPC HT strand was used for this project.

POST-TENSIONING TENDONSFor stressing, LP-300 multi pulling jacks wereinstalled at the blister from the inner edge ofthe beam. For single stage stressing, thedesigned jacking force for the 1905 tendon is2,617 kN and for the 1205 tendon the forceis 1,677 kN – 75% of UTS of the HT strand.Stressing was performed when the concretehad achieved 80% strength.

BENEFITSBy taking advantage of post-tensioningtechnology for cast in-situ beam

construction, the client has secured thebenefit of a shallow beam depth over alarge continuous span, a lighter structure –and ultimately cost-savings. Meanwhile,early deshuttering led to speedierconstruction and saved program time. It isclear that the customer was delighted, aswe have achieved a rating of 95% in ourCustomer Satisfaction Report. �

SPECIALAPPLICATIONS

TEAM &TECHNOLOGY

OWNER DY Patil Sports Academy

MAIN CONTRACTOR M/s Bitush & RajeevConstruction Pvt. Ltd

DESIGNER Eco Design India (P) Ltd


BBR NETWORK MEMBER BBR (India) Pvt Ltd

“THE BRIEF ALSO CALLEDFOR A LIGHTERSTRUCTURETHROUGH

INCREASED GRID SPANS ANDREDUCED STEEL SECTIONS –ASWELL AS COST SAVINGS.”

78 CONNÆCT

Catagunya Dam is owned and operated byHydro Tasmania and is located in centralTasmania.The dam was constructed in theearly 1960s and is one of a series of eight

dams on the Derwent River. Catagunya Damhas significant engineering heritage value – itwas the first post-tensioned damconstructed in Australia and at the time of

construction was the highest dam in theworld to use post-tensioned anchors.Thedam is 365 m wide and 48 m high, with itsspillway 126 m wide and 43 m high.Thedam’s power station has twin 24 MWturbines, each consuming up to 60 m3 ofwater per second.Recent investigations concluded that the 412original anchors were at the end of theiruseful life.The replacement anchorsincorporate the 9106 anchoring technology– previously developed and utilized byStructural Systems as a world first in our1999 Canning Dam project – but, withreduced availability of anchor locations, evenhigher capacity was sought.This led to theadoption of 91 x 15.7 mm strand tendons inlieu of 15.2 mm strands – 279 kN versus261 kN MBL – setting new world recordsfor permanent ground anchors, with an MBLof 25,389 kN, test load of 19,415 kN (1,980 t)and lock-off load of 17,772 kN (1,812 t).Structural Systems is at the leading edge ofdevelopment and execution of high capacityanchors, having built an extensive portfolio ofprojects and high acclaim, with other recordsof the longest ground anchor (142.02 m)and the heaviest ground anchor (over 16.5 t)on the Canning Dam project.The works incorporate 92 91-strand verticalanchors up to 77.8 m long, embedded up to30 m into hard dolerite rock below the dam.The 53 spillway anchors are located 8.5 mbelow the crest on the 56 degree slope, andthe remaining 39 are in the abutments.The anchorages developed and incorporatedare BBRVT CONA CMG 9106, fitted with

Recently revised dam safety standards, combined with theexisting ground anchors having reached the end of theirservice life, have prompted a refurbishment of Catagunya

Dam. Mark Seisun from Structural Systems explains how existingground anchors are being replaced with world record capacityanchors – using BBR VT CONA CMG 9106 technology.

World recordcapacity anchors

79CONNÆCT

low friction strand entry transitions andexternal threading for future monitoring,utilizing a purpose built load cell, atapproximately five year intervals throughoutthe anchor’s life.The use of the 9106 anchoring technologyfor the project has resulted in key benefitsfor the client – reduced costs andconstruction duration, whilst retaining thedam’s engineering heritage value through ananchored solution.Since the dam already contains 412 groundanchors, finding space for the replacementanchors amongst the existing ones waschallenging.The 92 high capacity 9106anchors, replace the obsolete anchors andalso provide a significant increase to thedam’s safety against flood and earthquake.Catagunya Dam poses several significantinstallation challenges – including theinstallation of anchors where the spillway isfive meters below the only access via theabutment.The solution involved the re-engineering of the installation frame tooperate straddling the two levels.Additionally, the installation of the longestanchors (77.8 m) is on a short abutmentwith inadequate approach distance, requiringa solution where a roller system is deployedto bend the anchors around a horizontal105 degree corner prior to reaching theinstallation frame.Each of the anchor’s 91 strands are greasedand sheathed over the free length, with theremaining 11.4 m of bare bond length strandsecured via grouting to the neighboring rock.A heavy duty HDPE corrugated sheath,

developed specifically for the project,provides primary corrosion protection in aflexible, but impermeable membraneencapsulating the entire anchor over the100+ year design life.The anchors are fabricated on site usingspecialist equipment to open each strand,fully greasing each wire, then reforming thestrand and installing it into a 20 mm HDPEsleeve over the free length.To maximize loadtransfer into the surrounding rock, the barebond length is cleaned and assembled tocreate an hourglass effect.The completed 9106 tendon is transportedto the dam on purpose-built trolleys. Initially,the corrugated and subsequent smoothpolyethylene sheathing is installed into theanchor hole by fusion welding of the 7.5 mindividual lengths.Installation of the tendon into the installedsheathing is achieved with a custom frame. A

large braking winch controls the rate ofanchor descent.The anchor is suspended inthe hole and grouted in three stages withClass G Oilwell Cement in the bond lengthand GP Cement for the free length. After 28days of grout curing, the anchors are stressedto their test and lock-off loads with a 2,200 tcapacity hydraulic jack.The anchoring works commenced in January2009 and are scheduled for completion inJune 2010 and, although the works are intheir early stages, both the StructuralSystems team and Hydro Tasmania client arevery satisfied with the progress to date – andhighly confident of successful projectcompletion, achieving the project’s safety,budget and program goals. �

SPECIALAPPLICATIONS

CATAGUNYA DAM UPGRADE, CENTRALTASMANIA, AUSTRALIA

TEAM &TECHNOLOGY

CLIENT & MAIN CONTRACTORHydro Tasmania

TECHNOLOGY BBRVT CONA CMG ground

BBR NETWORK MEMBER Structural SystemsLimited (Australia)

This road and rail bridge,connecting Maliaño andRaos docks, has been

constructed to enhance trade inthe Port of Santander – andrelieve one of the town’s majorstreets from around 200 heavyvehicle movements per day.Local traffic and residents willbenefit too – and harbor frontstreet, Marqués de la Hermida,can now be transformed into aseafront promenade. DavidOlivares Latorre of BBR PTEdescribes the project.

The 275 m composite steel bridge has threespans – the central span is a twin basculebridge with 36 m long deck sections.Thiscentral span is supported on two massivereinforced concrete blocks and anchored onpiled foundations.We were commissioned to position the fourdeck sections – perhaps the most interestingpart of the entire project – involving two100 m long side spans and the two centralbascule sections.By working with tide timetables, the deckstretches were positioned using the risingand falling tides – which, on some occasions,created a height differential in the water levelof over three meters.The composite steel decks were assembled,adjacent to the bridge superstructure, over aspecially-equipped barge – ready for shipping.For the two 100 m end spans of the bridge,we used four 200 t elevation jacks placed atstrategic locations.The bridge sections wereloaded onto a barge and positioned in theircorrect places at high tide.While the tidewas still at its peak, each deck section wassecured in its final position with the help oftopographical instruments.Then, as the tideslowly ebbed, the structure came to rest onthe vertical jacks and it was moved with amanual pulling operation.The same procedure was followed for thetwo central bascule sections – with onenotable addition, in the middle of the bridge,the two central bascule decks neededmillimetric precision to create a perfect joinbetween them in the centre of the bridge.As manual pulling was not efficient enough,we welded two 20 t hydraulic traction jacksto the structure and these provided veryeffective horizontal movement. �

80 CONNÆCT

Delivery for docks

MALIAÑO BRIDGE, SANTANDER, SPAIN

81CONNÆCT

SPECIALAPPLICATIONS

The objective of the project was toprotect the area under Mujib Bridge withadjacent 1.2 m diameter piles, up to 15 mdeep – for a total length of 3,600 m, aswell as providing a concrete raft supportedon 1.2 m diameter 20 m deep piles underthe bridge.Other special works included recon-struction of the Ogee weir using HighPerformance Concrete (HPC), protectionof the side of theWadi with 15 m deep1.2 m diameter adjacent piles for a totallength of 7,900 m and the protection ofthe downstream area of the Irish Crossingwith 1.5 m boulders.As required by the client, a preliminary pileload test was carried out on thefoundation piles for the protection worksat the bridge and the carrier pipes at

Mujib.This involved a vertical test load to13,400 kN – twice the vertical workingload which had been calculated.For this high load test, we had to design andconstruct four reaction piles and used 16anchor heads.The load was imposed on thetest pile head by means of two hydraulicjacks with a combined capacity of22,000 kN and the load was measured witha load cell. A cross-check of loadmeasurement was carried out via pressuregauge against a calibration table for thehydraulic jack.After completing the test and analyzing theresults, the final settlement – at workingload (6,700 kN) and after a holding timeof 60 minutes – was 1.83 mm, while thefinal settlement at a test load of 13,400 kN,after 360 minutes, was 5.85 mm.The residual settlement after the first cycleat 6,700 kN was 0.81 mm and, after thesecond cycle at 13,400 kN, was 2.35 mm.

�

In April 2006, a major flood took place which left massive damage and erosion inits wake and also threatened Mujib Bridge and Mujib Pump House.The city ofAmman relies on the pump house to deliver between 40 and 50 million cubic

meters of fresh water each year. BBR Network member,MarwanAlkurdi &Partners,was contracted for specialist engineering works designed to protect thevital infrastructure.

TEAM &TECHNOLOGY

CLIENTMinistry of PublicWorks and Housing

MAIN CONTRACTORMarwan Alkurdi & Partners Co. Ltd

DESIGNERDar Al-handasah (Shair and partner)


BBR NETWORK MEMBERMarwan Alkurdi & Partners Co. Ltd (Jordan)

Dealing with deluge danger

INFRASTRUCTURE PROTECTION WORKS, DEAD SEA, JORDAN

TEAM &TECHNOLOGY

OWNER Santander Port Authority

MAIN CONTRACTOR FCC Construcción S.A.

DESIGNER MC-2


BBR NETWORK MEMBERBBR Pretensados y Técnicas Especiales, S. L. (Spain)

82 CONNÆCT

Recently, a wind farm has been built in LakeVänern – the largest lake in Sweden.Spännteknik, the BBR Network member inSweden describes their role in delivering theVindpark Vänern wind energy project.Covering an area of 5,655 km2, Lake Vänern isthe third largest lake in Europe, located insouthern Sweden.The wind farm site is about8 km from the lake shore and, together, the tennew 90 m tall wind turbines will provide aninstalled energy capacity of 30 MW – it is

estimated that annual output will be90 million kWh.Our contract was for provision and installation ofrock anchors for the pylons. Foundations wereneeded at a depth of between 3-13 m – althoughthe lake is, in places, up to 106 m deep – and, byusing divers, the key tasks were executedsuccessfully.The round 6 m diameter foundations had beenprefabricated in 1 m high sections which hadrecesses for the cables. Each foundation was

Wind energy as a power source is an attractive alternative tofossil fuels because it is plentiful, renewable, widelydistributed, clean – and produces no greenhouse gas

emissions.Wind power accounts for about 1.5% of worldwide electricityusage and is growing rapidly, having more than doubled between 2005and today.

WIND FARM, LAKEVÄNERN, SWEDEN

WIN-WIND SITUATION

83CONNÆCT

To meet the ever increasing demand, windenergy towers will need to become taller –and post-tensioned concrete plays animportant role in realizing the full potentialof wind energy. Concrete tower solutionsare adaptable and durable and offer long lifeperformance with minimum maintenance.The use of precast or in-situ PT concrete,rather than steel, in the construction of windfarms offers several advantages to ownersand operators.� Reduced maintenance costs and long-lifeperformance – through comparativedurability of concrete over steel.

� Up to 15% higher energy production –PT concrete pylons can be 30-40 mhigher.

� Lower transportation costs – casting isnot highly specialized and can be carriedout near the site.

� Design and construction flexibility –versatility of concrete enables designsolutions with no restrictions on heightor size.

� Dynamic performance – PT concrete hasinherently high damping properties andcan deliver fatigue resistance solutionswith less noise emissions.

Taller wind towers need greater structuralstrength and stiffness to carry both theincreased turbine weight and bendingforces from wind action on the rotors andthe tower and also to avoid damagingresonance.Key issues are the minimization of materialcontent and structural weight andreduction of construction time. In-situslipform construction overcomes theproblems of transporting large tower ringsor sections and need for large cranes forerection.The ability to pre-stress concrete meansthat individual wind tower structures canbe tailored to provide optimal levels ofstiffness and dynamic performance usingpost-tensioned tendons.Ducts can be incorporated into bothprecast concrete units and in-situ concrete

– either located within pylon walls orexternally on the inner wall of the pylonstructure.This facilitates thin, lightweightwall construction with simple access forinspection and future capacity upgrades.A combination of internal and externaltendons can be considered whereby, forinstance, external tendons stabilize thetower from the base up to a defined stageand are anchored in a corbel. Internaltendons are stressed at full height from thetop corbel to the base segment.The move towards taller wind towers istipping the balance towards PT concretedesign solutions with their manyadvantages.BBRVT CONA CMX products – groundanchors, band systems, internal andexternal post-tensioning – are well-suitedto the construction of precast elements orin-situ concrete method used for windfarms.With the know-how of BBRNetwork members, concrete pylons couldreach heights of 120 m! �

length, both fixed and free, in one operation.As LakeVänern is such a massive lake – in fact,almost an ocean – it was a tough place inwhich to work, especially in the sometimesvery heavy wind conditions. On one occasion,we lost both a heavy compressor and ourliving quarters in a storm!We have successfully completed our task –the windmills are installed and we arelooking forward to our next green energychallenge. �

anchored by 16 BBR CONA 1906 rockanchors – with a length of 25-28 m,depending on the water depth.Our scope of work was to drill holes in therock through the recesses in the foundations,perform a water tightness test and, ifnecessary, tighten the holes by cementgrouting.The next step was to install, groutand stress the cables.The cables consisted of 1906 PE-coated strand– this allowed us to grout the whole cable

SPECIALAPPLICATIONS

Technical insight:Post-tensioned concrete windmills

TEAM &TECHNOLOGY

OWNER / OPERATOR Drift AB / Kraft AB

MAIN CONTRACTORPEAB Sverige AB, Sweden

DESIGNERInhouse Tech. AB

TECHNOLOGYBBR CONA rock anchors

BBR NETWORK MEMBERSpännteknik AB (Sweden)

84 CONNÆCT

Asegmental precastpontoon has beenconstructed at Lumut Port

in Perak, Malaysia.The site faces theStraits of Melaka and the finishedpontoon forms part of the jetty ofthe sea sanctuary resort.Yok-LinVoon of BBR ConstructionSystems, the BBR Networkmember in Malaysia, explains howthe reinforced concrete floatingpontoon was built.

The pontoon is 7 m wide, 30 m long and2.9 m in depth. It is comprised of tenhollow segments which needed to beassembled and then stitched togetherusing epoxy and post-tensioning.Theprecast segments were manufactured offsite, then transported to a dry dockwhere they were assembled and stitchedtogether.We were invited to install thepost-tensioning works for the pontoon, aswe had the know-how to complete thischallenging task successfully.Each segment is designed as a concealedhollow box. Even if one box were to bepartially filled with water, the water wouldnot be able to pass into adjacent boxes – aTitanic-scenario could never happen here!The 300 mm x 300 mm piles, acting assleepers, were laid on the dry dock floor,spaced 1.5 m apart, to support the railpiles. Each concrete segment was loweredby a 200 t crane onto four 150 t jacks,where the levels were adjusted to suit therails.Then, the jack pistons were lowered totransfer the weight of the segment ontosliding steel plates resting on the rails which

had been lubricated with grease.Thealignment of the sliding segment withsegments already assembled wasmaintained by guide plates which couldslide over the top flanges of the guide rails.Epoxy paste was applied to the verticalface of the segment.Then the segment waspulled towards the previously assembledsegments by stressing four 12.7 mmdiameter temporary strands simultaneouslyusing monojacks – each pulling about a 9 tforce.The permanent tendons are 59 BBRCONA single 15.7 mm diameter strands.The strands used were greased and PEsheathed to protect them from themarine environment.The unbondedstrand was threaded through ducts castinto the segments. After stressing, the ductwas cement grouted for additionalprotection against corrosion.Finally water was let in, filling up the drydock – and the completed pontoon wasfloated out to sea. �

At Singapore’s ChangiAirport, a new S$135million Automated

People Mover System (PMS)has replaced the existing sky-train service connectingTerminals 1 and 2 and nowaccommodates demands fromthe new Terminal 3. The PMScarries passengers between allthree terminals on a total of6,400 m of single lane, doublelane and by-pass shuttleconfigurations guideway,connecting six stationsintegrated within the terminalbuildings.

Construction was carried out in two phases.The first phase (Phase 1A) started with theclosure of one of the existing sky-train lanesconnecting Terminal 1 to Terminal 2.The client’s contractor then retrofitted thisguideway for the new systems. Construction

Sky’s the limitPEOPLE MOVER SYSTEMS,CHANGI AIRPORT, SINGAPORE

TEAM &TECHNOLOGY

OWNERMarine Sanctuary Resort Sdn Bhd

MAIN CONTRACTOR Marina IslandConstruction Management Sdn Bhd

CONSULTANT Perunding Aziz Sehu Sdn Bhd

TECHNOLOGY BBR CONA unbonded

BBR NETWORK MEMBERBBR Construction Systems (M) Sdn Bhd

SEGMENTAL PONTOON, LUMUT PORT, PERAK, MALAYSIA

Floating concrete jetty

Mega year in AsiaRecently, heavy lifting and transport solutions specialist, Mammoet has beenparticularly busy inAsia. In a five month period, they undertook three majorjack-ups with weights of up to 14,000 t and lifts of up to 23 m.The latestweighing technology – BBRWIGAbloc – was used to determine the exactloads for a safe and optimized operation.The SuTuVang CPP Deck project in Batam, Indonesia, involved the construction of a plat-form at 5.5 m above ground level and about 170 m from the quayside.The platform wasjacked up using BBR WIGAbloc weighing equipment for this mega load-out of 14,000 t.This giant construction was supported by ten legs, each covering three BBR WIGAblocload cells – with a 6,000 kN capacity each – in a triangular configuration.The uniquetilt capability of the BBR WIGAbloc design distributed the load equally over the threepoints, ensuring an accurate loading for each leg.The two other projects were the Angel CPP Deck (8,000 t, 23 m) in Malaysia and inSingapore, the Jurong Semi-Sub 1088 (10,000 t, 19 m).BBR WIGAbloc load cells are measuring instruments for compression forces and comein a range from 5 to 20,000 kN. �

85CONNÆCT

of the new guideways (Phase 1B) whichconnect Terminal 3 to Terminal 1 andTerminal 2 was carried out concurrently.The second phase started after theretrofitting works during Phase 1A hadbeen completed. All existing sky-trainservices were then stopped and the client’scontractor retrofitted the remaining sky-train infrastructure.The up-stand beams – post-tensioned withBBR CONA internal – spanned between9.6 m to 25.4 m and support the cantileverslab, running plinth, M&E equipment and themovable load from the moving carriages.We used BBR CONA flat for the post-tensioned slab which spanned up to 12 m

SPECIALAPPLICATIONS

and cantilevered up to 4.8 m – the slabthickness varies from 250 mm to 400 mm.The nature of this project demanded thatwe should consider additional factors duringthe design stage:

Structure Systems� Single lane guideway – post-tensioned beams were integrated intothe structure as one of the externalparapet walls, supporting the RCcantilever slab.

� Double lanes guideway – post-tensioned beams were integrated intothe structure as the central divider,supporting the balanced RC cantileverslab.

� By-pass shuttle / washing bay – post-tensioned beams were integrated intothe systems as the central divider andthe external parapet walls, supportingthe post-tensioned slab.

� Torsional moment caused by thecurvature in plan for the PT beams.

� Torsional moment caused by the movingcarriages running on the RC cantilever slab.

� Cyclic loading and dynamic factor causedby the moving carriages.

� Concrete cover for fire protection andexposure to outdoor weather.

With the opening of Terminal 3, the capacityof Changi Airport has increased by an addi-tional 22 million passengers a year – and thenew PMS is ready to welcome them all! �

TEAM &TECHNOLOGY

OWNERCivil Aviation Authority of Singapore (CAAS)

MAIN CONTRACTOR Evan Lim & Co. Pte. Ltd(Terminal 1 & 2, Guideway)& Shimizu Corporation (Terminal 3)

C&S CONSULTANT CPG Consultants Pte. Ltd.(Airport Development)

TECHNOLOGY BBR CONA internalBBR CONA flat

BBR NETWORK MEMBER BBR ConstructionSystems Pte Ltd (Singapore)

86 CONNÆCT

“THE STRESSINGFORCE OF THE STAYCABLES LIES

BETWEEN 1,501 KN AND2,367 KN,WHICHREPRESENTS 15.3% AND16.2% OF THE MINIMUMBREAKING LOAD OF THECABLES.”

U2/6 DONAUMARINA BRIDGE,VIENNA, AUSTRIA

87CONNÆCT

During lifting of the nearby A23 motorway bridge,the bridge was used as an alternative route for cartraffic to cross the River Danube. In the secondphase, which lasted almost ten years, only publicbuses and emergency vehicles were permitted touse the bridge. However, right from the beginning,the superstructure was designed as a metro bridgefor the extension of the U2 metro line – and itsfinal metamorphosis was achieved in 2008.The Donaumarina Bridge is a steel construction,with an A-shaped pylon and a total length of343.5 m and a 186 m main span.The 139.5 mback span has two pressure props 18 m away fromthe counter-bearing to reduce the tangent anglebetween the main span and the concrete sidespans.Two pin-ended columns in the back span –46.5 m from the counter bearing – transfer tensileforces from the structure into the foundation.

NEW STAY CABLESSteel strands with a nominal cross-section of150 mm² and a maximum characteristic tensilestrength of 1,770 N/mm² were used for the staycables. For corrosion protection the strands are

greased and have a factory-manufactured HDPEsheathing.They were delivered to site in coils with amaximum weight of 3,454 kg.Twenty stay cables, oftwo different types, were installed – eachconsisting of a combination of monostrands andcompact mono bands. Stressing was carried outfrom the tower head of the pylon – using multi-strand jacks capable of applying a maximumstressing force of 10,000 kN.The hollow spacebetween the strands was filled with cement grout,as an additional corrosion protection layer and forfire protection.

PREFABRICATIONThe prefabrication of the new stay cables wascompleted on the bridge deck of the back andside spans. However, in late April 2008, nearly allthe monostrands which were stored on site, wereset alight in an arson attack – the perpetratorwho committed this offence was never caught.Only three coils, which had already been liftedonto the bridge deck and placed in uncoilingframes, were not destroyed – 20 steel coils hadbeen destroyed in the incident. �

Vienna’s ‘Donaumarina’ cable-stayed bridge was built in the late1990s to fulfill three different purposes, reports Jürgen Diatel ofVORSPANN-TECHNIK, the BBR Network member in Austria.

MRR

88 CONNÆCT

After the replacement of the prestressingsteel, the strands where uncoiled and pulledinto the welded HDPE tubes. For a moredistinctive architectural appearance, the tubeshave a grey colored outer layer which isachieved by co-extrusion during tubeproduction – this was a VT invention!

INSTALLATION AND STRESSINGStay cable anchorage blocks with externalthreads and fixed steel trumpet pipes weremounted on both ends.The ring wedges andwedge retaining plates were assembledafterwards.The stay cables were lifted byusing mobile cranes. First, the upper cableends were inserted into the penetrationpipes and fixed with stay cable anchoragenuts – a similar procedure was followed forthe lower anchorages near the bridge deck.The stressing force of the stay cables liesbetween 1,501 kN and 2,367 kN, whichrepresents 15.3% and 16.2% of the minimumbreaking load of the cables. Four cables –two upstream and two downstream – werestressed simultaneously.The stay cables were filled with cementgrout of a 30 N/mm² minimum compressivestrength.Finally, the stay cable anchorages werecovered with corrosion protection bands andthe remaining overlaps of strands werecovered with a PE-coating and PE-caps wereinstalled. �

TEAM &TECHNOLOGY

OWNER Wiener Linien,Vienna, Austria

MAIN CONTRACTORPorr Technobau und Umwelt AG

CONSULTANT Büro Pauser ZT GmbH

TECHNOLOGY VT stay cables


89CONNÆCT

In Focus:Vienna’s underground network

The metro – or U-Bahn – in Vienna consists of five railway lines, some of which have their origins in thelate 1800s.The first section of the modern metro system opened in 1976 and, today, it is run – along withthe city’s bus and tram network – byWiener Linien who are progressively extending the U2 metro line.

The upgrading of the Donaumarina Bridge is part of the third phase of development – and, by 2019,Vienna’s underground network will have extended by a further 20 km, to almost 90 km of track. Most

recently, the U2 line was extended to serve the Ernst Happel Stadium and completed in time to transportfans to the seven games of the UEFA Euro 2008 football tournament which were hosted here.

The level of investment earmarked to complete the major U2 extension scheme is in the region of €9billion.The infrastructure operator believes that the new line will act as a driving force for the local

economy – and reports that its construction has already generated some 24,000 new jobs.

MRR

90 CONNÆCT

FACTORY ROOF STRENGTHENING, PABIANICE,POLAND

STRONG SOLUTION

When the steel roof girders at the Philips Lightingfactory in Pabianice needed strengthening,BBRPolska devised an effective solution which allowed

normal business to continue. Project manager, M. Sc. BartoszŁukijaniuk takes up the story.This problem had occurred in two factory buildings where 30 m longsteel and concrete girders which had been installed in the 1970s – andprestressed with internal tendons. Company management discoveredthat the girders were deflecting too much and sought specialist advice.The expert’s opinion was that the old tendons were losing theirstressing force because of corrosion and that the girders neededstrengthening. Suddenly, a seemingly simple situation had becomecomplex – the roof needed repairs, but production in the factorycould not be stopped for more than two or three days.So, the BBR Polska team came up with the idea of using externaltendons to take over the forces from the old rusty tendons andrestore the girders to their original status. Our design required onlysmall additions to the steel structure – for example, anchorage blocksto be welded to the girders. A sensor has been installed on eachtendon to allow future monitoring of the structure.The design was carried out by SDS (Structural Design Service) in co-operation with BBR Polska.In the first building, installation of the additional steel elements wascompleted without stopping factory production – even for one day.However, factory management themselves decided to halt productionfor two days – during which time we had to stress all tendons ... andwe did it! Now, we are working on the second factory building –perhaps the subject for a further report in the next edition ofCONNAECT. �

BLOOMINGDALES STORE, DUBAI MALL,DUBAI, UNITED ARAB EMIRATES

Testament to PT flexibility

The US$722 million Dubai Mall, currently underconstruction, is set to be the largest mall in the

world, as well as the counterpart to the Burj Dubai –the world’s tallest tower. BBR Network Member,NASAStructural Systems LLC, reports on a specialcontract to accommodate the needs of the famous USdepartment store, Bloomingdales which has venturedto open its first store outside of the United States.

When completed, the Dubai Mall will be larger than 50international soccer pitches and is expected to attract over35 million visitors in its first year of operation.The mallfeatures 1.6 million square meters of retail space whichincludes 1,400 shops.Bloomingdales requirement of 146,000 ft2 of floor space overthree successive levels of the Mall complex necessitatedstrategic slab openings to be created within the existing post-tensioned (PT) floor slabs for the installation of escalators.BBR Network Member, NASA Structural Systems LLC, wasengaged by fit–out contractor Al Tayer Stocks LLC to carryout the specialist works which involved the chemicalanchoring of the post-tensioning tendons along the criticalperimeter of the slab, saw-cutting, waste management andremoval, corrosion protection of end reinforcement, makinggood of slab edge openings and installation of structural steelsupport beams.Work was completed successfully within a tight time framewhich enabled follow-on trades to commence work and meetthe store opening date of February 2010.The flexibility ofpost-tensioned floors to support post-construction planningwas again proven by NASA Structural Systems – even tohard-nosed conventional reinforced concrete purists! �

TEAM &TECHNOLOGY

OWNER Philips Lighting Poland S.A.

MAIN CONTRACTOR Mostostal Warszawa S.A.

STRUCTURAL ENGINEERStructural Desgin Service (SDS) / BBR Polska Sp. z o.o

TECHNOLOGY BBR CONA external

BBR NETWORK MEMBER BBR Polska SP z o.o (Poland)

TEAM &TECHNOLOGY

OWNER Bloomingdales

MAIN CONTRACTOR Al Tayer Stocks LLC

CONSULTANT Meinhardt (Singapore) Pte Ltd

TECHNOLOGY MRR range

BBR NETWORK MEMBERNASA Structural Systems LLC (United Arab Emirates)

91CONNÆCT

BBR Network memberStructural Systems UKLimited has recently

been helping to breathe newlife into an existing building inLondon by carrying outstrengthening work – giving thestructure a new life andpurpose.

Occupying a prime spot at the corner ofIslington’s Upper Street and Pentonville Roadin London, the Angel Building – a formerBritish Telecom telephone exchange andoffices – is currently being redeveloped.Thescheme will provide ground floor retail spacewith modern office facilities above.Loads to be factored into our design work forthe strengthening included the construction ofa new steel fifth floor, an external terracedarea and the installation of a BMU (BuildingMaintenance Unit) to track around thebuilding edge.There were also additionalservice penetrations, typically 2 m x 1 m

lightwells in the fifth floor, as well as otherservice penetrations through all floors as partof the renovation work and the formation offive 5 m² staircase openings.One unusual detail of the construction is that,above first floor, the structure is two-wayspanning flat slab – whereas at first floor it is aone-way spanning slab with drop beams.Structural Systems was appointed by BAMConstruction to carry out the strengtheningworks using FRP material in association with aBL5800 adhesive. Specialist epoxy mortarswere used to carry out substantial substraterepairs and a flow-able epoxy grout was usedfor filling in the redundant gullies.We designed and installed all of the FRPcomponents and the installation was carriedout by our own specialist installers.We alsocarried out some of the initial structuralinvestigations to confirm the monolithic natureof the fifth floor slab, as the falls which werepresent could have been a screed finish.It turned out that the falls formed part of theroof structure, so this involved some complexplanning to get all the FRP areas reduced

down to a common level. Our engineers alsodesigned some areas of slab in-fill toovercome some of the falls issues.We were selected for the project because ofour proactive approach during the initialphases, offering design and operationalsolutions at every stage.The eventual finaldesign was carried out in-house, as were thefull installation works, all of which werecovered under a single warranty, which wasalso attractive to the client.The client waslooking for a flexible organisation with aproven track record who could deliver thewhole package, as well as work with othertrades during the initial program phase. �

MRR

TEAM &TECHNOLOGY

OWNER Derwent London plc

MAIN CONTRACTOR BAM Construction

DESIGNER Price Myers ConsultingEngineers/Structural Systems UK Ltd



THE ANGEL BUILDING,LONDON, UK

92 CONNÆCT

The bridge, which occupies a dramaticposition across Grafton Gully in Auckland,was part of a program of regional roadbuilding and symbolized both the creation ofa ‘Greater Auckland’ and state leadership inthe development of technology. Sanctionedby ratepayers at the very end of the Britishcolonial period (1840-1907), it also displayedthe new Dominion’s ability to lead the worldin its progressive outlook.The bridge has a large central span of 98 m,

with three smaller spans on its easternapproach and six on its west. It is 296 m longand stands 43 m above the gully floor. It isbuilt entirely of reinforced concrete, with thegirders in its approaches being claimed as thelongest continuous segments in the world atthe time.The structural upgrade, being carried out bymain contractor Brian Perry Civil, will provideearthquake resistance and additional load-carrying capability.The structural and seismicupgrade will not change the way GraftonBridge looks or change its heritage status.In the original design of this bridge structure,no allowances were made for earthquakeresistance. Now, the bridge will bestrengthened to withstand a one-in-1,000-year earthquake, in accordance with modernearthquake design standards. In addition, thestructural upgrade will mean the bridge can

carry increased bus traffic, and be future-proofed to handle new transporttechnologies, such as light rail.The work being undertaken includes:� Strengthening the bridge columns, usingsteel bar reinforcements – a techniquealso used on the Auckland Harbor Bridge.

� Strengthening the bridge beams, byapplying a carbon fiber material to theexisting concrete beams.

� Installing new, reinforced concrete shearkeys and deck lineage to resist horizontalearthquake forces.

With the world’s largest single span of reinforced concrete,Grafton Bridge was at the forefront of construction

technology when it was completed in 1910. BBR ContechProject Manager, Hugo Jackson reports how – 100 years on – thebridge is being strengthened as part of the Auckland CentralConnector Project with state-of-the-art carbon fiber composites –again placing this iconic structure at the forefront of latestconstruction technology.

Grafton Bridge CVGrafton Bridge is of national andinternational significance for its use ofadvanced concrete technology – and isalso considered of internationalimportance as an engineering structureof unique value.� Longest reinforced concrete arch inthe world when completed in 1910.

� Category 1 – highest classification –given by New Zealand HistoricPlaces Trust in recognition of itsoutstanding technological merit andmagnificence as a townscapeelement.

� Recognized in 2004 by the AmericanConcrete Institute publication,Concrete: A Pictorial Celebration– featuring landmark concreteachievements.

� Awarded the inaugural New ZealandConcrete Society Enduring ConcreteAward in 2008.

Centuryof progressive technology

93CONNÆCT

� Repairing cracks in the existing concreteand removing algal growth.

� Applying a ‘modified cementitious coating’to prevent further corrosion.The coatingprovides protection from concretecarbonation.

� Replacing joints and bridge bearings.BBR Contech was engaged by principalconsultant Beca Infrastructure in 2007 toconduct load testing of the existing bridge.As a result of this testing, a scheme to

strengthen the bridge using fiber reinforcedplastic plates was developed.In 2008, a contract was let to Brian PerryCivil to perform a number of strengtheningand preservation works. BBR Contech wasengaged as a specialist to supply and applynearly 600 m of FRP strip and plates.Thesystems are pre-manufactured ultra highstrength carbon fiber laminate platesapproximately 1.5 mm thick and 100 mmwide which are adhered to the prepared

concrete surface with a specifically developedepoxy adhesive. Strips were applied to theunderside of the beams to provide additionalmid-span moment resistance.The plateswere installed, in pairs, around the beamsand up into the deck slab, to improve shearperformance.This project was completed well ahead ofschedule in late 2009 and will ensure thisgrand old lady will continue to serve Auck-landers for many generations to come. �

MRR

TEAM &TECHNOLOGY

OWNER Derwent London plc

MAIN CONTRACTOR BAM Construction

DESIGNER Price Myers Consulting Engineers /Structural Systems (UK) Ltd



GRAFTON BRIDGE, AUCKLAND NEW ZEALAND

94 CONNÆCT

KINGS WHARF UPGRADEKingsWharf has also been in operation foraround 100 years and was one of theoriginal wharves servicing the Port ofWellington. It is now used by Strait Shippingto marshal and load hundreds of thousandsof tonnes of livestock and cargo freightbetween the North and South Island all yearround.

Deck & beam deteriorationThe timber wharf deck and supportingbeams were showing signs of deterioration.With the piles still in sound condition,

CentrePort investigated solutions to apply astructural overlay to effectively replace theexisting timber deck. A low shrinkageconcrete overlay was required and advicewas sought from Allied Concrete Limited.

PT slab solutionBased on the wide experience and longtrack record of post-tensioned floor slabsand a close relationship with BBR Contech,Allied Concrete proposed that thestructural overlay could be provided by apost-tensioned slab – utilizing the existingtimber deck as permanent formwork.

Collaborative inputWorking in close collaboration withCentrePort, Holmes Consulting and fulldelivery floor contractor Conslab, BBRContech prepared a design / build post-tensioned overlay proposal for the 7,000 m2

wharf. BBR Contech again received valuabledesign input from Australian BBR Networkmember Structural Systems and the finalconfiguration comprised an overlay completedin four separate pours, each measuringapproximately 60 m x 35 m.

Special PT considerationsThe post-tensioned overlay required somespecial considerations for deflection of theexisting timber deck and the final layoutcomprised a 180 mm thick flat slab and BBRCONA flat 0405 tendons.The post-tensioned overlay was completed instages to allow suitable preparation of theexisting deck.The finished deck sections wereprogressively handed over to CentrePort toensure there was only minimal disruption toongoing shipping operations.

While the company has vast experience and capability in the maintenance, repair andretrofit of a wide range of concrete structures – including bridges, electricity utilities, waterand wastewater facilities, buildings, dams and towers – several recent wharf projects,presented here, illustrate the breadth of expertise developed over many years.

Undertaking challenging remedial projects is a particularstrength of our New Zealand-based BBR Network member,BBR Contech – an area of special expertise relates to

repair work on wharves.

WINNINGWAYSWHARF UPGRADING, NEW ZEALAND

95CONNÆCT

CENTREPORT – WELLINGTON PORTCOMPANYCentrePortWellington is a pivotal portfacility located in the geographic centre ofNew Zealand in a natural sheltered deepwater harbor. It offers direct nationwideaccess to the major highways and main trunkrailway. Key coastal shipping and inter-islandferry services are also located within theport precinct.The port has large number of importantinfrastructure assets including wharves,warehouses and cold store facilities and BBRContech has a long association with the portcompany in maintenance and newconstruction.

Thorndon Container WharfThorndon ContainerWharf is the maincontainer handling wharf in the port. It is alarge wharf operating two berths, eachmeasuring some 300 m in length, andcovering a total area of approximately15,000 m2.

BBR Contech is carrying out the work in ajoint venture with world leaders in cathodicprotection technology, Savcor ART ofAustralia.The work has been staged byCentrePort and the current contract involvesconcrete repair and cathodic protection tothe second shipping berth of ThorndonWharf.The facility must continue to functionas a fully operational container wharf, whilstrehabilitation works are being carried out.

Cathodic protectionThe rehabilitation design calls for theapplication of an impressed current cathodicprotection system to the front crane beam,rear abutment wall, transverse deck supportbeams and selected piles – with preventativemaintenance coatings applied to the entireunder-wharf surface area.The deteriorationof concrete elements is worst at the frontand rear of the wharf – the majority of workis concentrated in these zones.

Other techniquesHydro-demolition techniques are again being

employed for concrete removal andconcrete reinstatement is being carried outusing proprietary gunite materials. Not allelements are receiving impressed currentcathodic protection and some of theconcrete elements are being repaired byconventional concrete repair methods inconjunction with sacrificial anodes attachedto rebar prior to the application of repairmortar.

Long term solutionIn addition to Thorndon ContainerWharf,the Joint Venture is also employed to makesimilar repairs to DockWharf, anotherimportant wharf asset which services thebusy Interislander passenger and car ferry –the main link between the North and Southislands.When completed, these two projectsare designed to provide long-termprotection and life extension for these criticalinfrastructure assets for more than 30 yearswith minimal ongoing maintenance or furtherdeterioration. �

MRR

with wharves

96 CONNÆCT

DOWNTOWN AUCKLANDThe Auckland Downtown Ferry Terminal isthe hub of Auckland’s ferry network – anetwork that began in 1905 and whichconnects Auckland’s CBD with the widerAuckland area.After 100 years of service, thehistoric piers that make up the DowntownFerry Terminal now require repairs to thestructural fabric beneath the deck to maintainthem in a safe condition for the continued useof Auckland’s ferry commuters.

Work underwayConcrete repair work commenced on Piers1 and 2 adjacent to the historic ferry buildingin mid-2008 and is expected to continueinto 2010.The concrete piles, deck beams,cross-bracing and deck soffit are badlydeteriorated and the repairs are designed toreinstate the damaged areas and restore theintegrity of the elements.

Repair techniquesThe repair techniques employed includeguniting and forming and pouring using highperformance micro-concretes. All defectiveconcrete is removed using hydro-demolitionto minimize the noise associated withtraditional concrete breakout.This is animportant project and much of the existingsub-structure has to be temporarilysupported due to the degree of deterioration.

�TEAM &TECHNOLOGYThorndon ContainerWharf andDockWharf

OWNER CentrePort Ltd

STRUCTURAL ENGINEER & CP DESIGNERGHD Consultants

CONTRACTOR Savcor-Contech Joint Venture



TEAM &TECHNOLOGYAuckland Downtoown FerryTerminalupgrade

OWNER Auckland Regional Transport Authority

STRUCTURAL ENGINEER URS New Zealand



TEAM &TECHNOLOGYKingsWharf upgrade

OWNER CentrePort Ltd

STRUCTURAL ENGINEERHolmes Consulting Ltd

CONTRACTOR Conslab Ltd


BBR NETWORK MEMBERBBR Contech (New Zealand) (construction)Structural Systems Ltd (Australia) (slab design)

“THIS IS AN IMPORTANTPROJECT AND MUCHOF THE EXISTING SUB-

STRUCTURE HAS TO BETEMPORARILY SUPPORTEDDUE TO THE DEGREE OFDETERIORATION.”

97CONNÆCT

As a part of an earthquake disastermanagement plan in India, a number of

important structures which will form a lifeline inthe wake of such an event, have been identifiedfor seismic retrofitting.These ‘lifeline buildings’will accommodate the most essential facilitiesneeded for saving lives and carrying out rescueoperations. Mr Veeramani, project manager forBBR (India) Pvt Limited, describes theexecution of a pilot project in New Delhi.Ludlow Castle School accommodates about 1,700students and has been listed for use as anemergency shelter in the wake of an earthquake.This 40-year old building, on the banks of RiverYamuna, has three floors and is of brick / masonryconstruction.Masonry buildings are brittle structures and one ofthe most vulnerable during seismic events. Ourretrofitting measures are based on the national BIScodes.The technique adopted was to strengthenvulnerable points by providing additional cast-in-situFerro cement plating on the masonry wall facewith a containment system, along the critical loadpaths – thus strengthening and integrating thewhole structure.The various measures adopted were:� Encasement of all wall openings – including thedoors and windows.

� Lintel level seismic belt on both sides of everywall.

� Sill level belt on both sides of every wall.� Vertical reinforcement – consisting of weld wiremesh or reinforcing rod – at every walljunction.

� Since vertical bars at the jambs of windows anddoors were not present, seismic belts wereprovided all around the openings.

The materials used include cement, galvanizedsteel, non-shrink high strength flowable micro con-crete, epoxy resins grout and mechanical anchors.The project is a model program for seismicevaluation and retrofit which can be replicatedthroughout India. �

MRR

Back to school

SEISMIC RETROFITTING OF SCHOOL,NEW DELHI, INDIA

TEAM &TECHNOLOGY

OWNER PublicWorks Department, Delhi

MAIN CONTRACTOR M/S BBR India Pvt Ltd

DESIGNER Committee of Expertise formed by Govt. ofIndia / Team from GEO Hazard International workingtowards global earthquake safety


BBR NETWORK MEMBER BBR (India) Pvt Ltd

The bridge over theWouriRiver between Douala andBonaberi was built in 1954

and was the world’s largest multi-span bridge at that time, reportsJean-MarcVerplaetse of French BBRNetwork member ETIC.Over the years, the very humid climatehad caused severe corrosion leading toconcrete cracking and broken PTstrands. As the only bridge in Doualaprovince, it has an important economicrole to play in the region. So, to keeptraffic and trade moving until a long-awaited second bridge can beconstructed, retrofitting works were vital.There are 16 spans – each 42 m longspan consists of 10 post-tensioned ‘I’beams joined by four post-tensionedtransversal cross-beams. Pier caps arealso post-tensioned.Around 20% of thepost-tensioning strand – originallysupplied by another manufacturer – wasbroken and there were many cracks inthe lower parts of the concrete beamsand crossbeams.It was decided that the followingexternal additional post-tensioning cablesshould be installed:� Longitudinal additional post-

tensioning – four unbonded BBRCONA single 06" cables on each sideof the beams

� Additional transversal post-tensioning – four unbonded BBRCONA single 06" on each side of thecrossbeams

� Pier caps – on four piers, eightunbonded BBR CONA single 06" oneach side of the pier cap

Among the technical challenges that ourteam had to face included having toredesign the bridge from measurementstaken, as there were no technicaldrawings and working in a live trafficsituation – we executed most of ourwork from the river which had strongcurrents and was subject to tidal flow.Our retrofitting project was completedto the full satisfaction of the Ministry ofPublicWorks.The bridge has nowregained at least some of its formeryouth and can be used safely for manyfuture years, until that illusive secondbridge over theWouri River finallyarrives … �

TEAM &TECHNOLOGY

OWNER Ministry of PublicWorks of theRepublic of Cameroon

CONTRACTORS UDECTO (Togo) forretrofitting of foundations, concrete surfaces,roadway and parapets

ETIC International (France) – for retrofittingof post-tensioning.

CONSULTANT EGIS France

TECHNOLOGY BBR CONA external

BBR NETWORK MEMBER ETIC (France)

PRESERVING VITAL LINKWOURI RIVER BRIDGE, DOUALA, CAMEROON

98 CONNÆCT

The Rixos Ottoman Palace Hotel is a five-star,seven storey hotel and villa project, designedby renownedTurkish architect Kürsat Aybakto blend the rich lifestyle of ancient Turkishculture with modern day luxury.There are410 rooms and a further 38 villas, each havingits own individual swimming pool and garden.It is located on the crescent of The PalmJumeirah – an artificial island created by Dubaigovernment-owned developer Nakheel.When construction started, good progresswas made and the project was expected tobe completed in record time. Unfortunately,several months into the constructionprogram, a fire broke out causing damage tothe basement and ground floor areas.Afterwards, there was concern about thestructural integrity of part of the building andlocal regulatory authorities required an

independent assessment.Tests includedhammer sounding, ultrasound pulse velocityand petrographic inspection / analysis todetermine and confirm the depth of concreteaffected in each structural member.The net result was the appointment of NASAStructural Systems LLC to undertakerectification work on the fire-damagedbasement and ground floor.This was to be thefirst remedial project for the StructuralSystems Group in the Middle East region –having only launched our Middle EastRemedial Division a few months earlier. Ourworkscope included the complete supply,supervision and installation of materials for therefurbishment work.Lateral bracing was installed in the basementand ground floor areas to support thecolumns, preventing them from bucklingduring the period of demolition andreplacement of the ground floor slab.The surface of the columns requiringjacketing were then roughened by scabbling.Cores were drilled through the slab above,adjacent to the perimeter of the beam, toallow pouring of a high early strength microconcrete. New reinforcement was fixed,shutters were set in place and the grout waspoured though the core holes above. Afteran initial curing period, the shutters wereremoved from around the columns – withfurther curing achieved by wrapping the

columns in wet hessian, in line with bestpractice.A ‘crash deck’ – including high density styrenesheeting to act as a sandwich between theform ply and the concrete – was thenconstructed over falsework to the soffit of thebasement to allow the concrete cutting to becarried out from the ground floor deck.The concrete slab was cut into 1 m x 1 msections and removed from site manually – viathe basement – by lowering the sectionsthrough a specially constructed opening in theformwork.The styrene was then removed and

Spanning parts of south-eastern Europe, the Middle East andNorth Africa, the Ottoman Empire became a world power atthe very centre of interaction of the eastern and western

worlds – this diverse dynasty endured for six centuries. Today,after a set-back, a superb leisure resort reflecting this heritage isa step nearer to completion with help from NASA StructuralSystems – the BBR Network member in the United Arab Emirates.Rob Sutherland, their Remedial Business Manager reports.

Scope of works� Enlargement and making good ofsome 33 columns (columnjacketing) in order to restore theirshear capacity.

� Repair to staircase walls, includingremoval of crazed and spalledconcrete and reinstatement usingproprietary repair material.

� Installation of temporary lateralbracing beams.

� Construction of falsework tosupport and enable cutting andremoval of the fire-affectedconcrete slab sections.

� Removal of 1,600 m2 x 300 mmthick concrete floor slab byconcrete cutting.

� Slab reinstatement, includingconnection of new reinforcing barsto existing bars by using couplers.

� Installation of bearing angles atcolumn locations.

99CONNÆCT

the crash deck reconfigured to the correct lineand level. Existing reinforcement at the slabedge was exposed so that special couplerscould be connected to provide necessarycontinuity of the reinforcement.Several ground floor beams required a70 mm thickening. High pressure water-blasting was used to roughen the surface ofthe beams, appropriate core holes were

drilled through the slab, with shear pins andreinforcement epoxied into place.The beamswere then formed using traditionalformwork and cast by pouring high earlystrength micro-concrete to just below thesoffit. After formwork was removed,structural repair mortars were hand-appliedto complete the thickening operation.Once the enlargement of the columns and

beams had been completed and reinstatedconcrete had reached a 28-day compressivestrength of 40 MPa, the lateral bracing wasremoved – leaving the building structurallyintact.The project was completedsuccessfully by NASA Structural Systems to ahigh quality – meeting the exceptionalstandards of the Ottoman tradition and,indeed, our client! �

MRR

REMEDY FOR RIXOS

TEAM &TECHNOLOGY

OWNER Zabeel Properties

MAIN CONTRACTOR ZSML Construction

CONSULTANTShadid Engineering Consultants



FIRE DAMAGE RECTIFICATION, DUBAI, UNITED ARAB EMIRATES

100 CONNÆCT

Stadium construction has its roots in ancientGreece where the oldest known is atOlympia in the Peloponnese and was hometo the Olympic Games from 776 BC.In fact, the word ‘stadium’ comes from theGreek word ‘stadion’ which was a measureof length equating roughly to 180-200 m.TheGames originally consisted of a single sprint

of injured competitors.Through the pages ofthis and earlier editions of CONNAECT, itcan be seen that BBR Technology – alongwith the engineering expertise, ingenuity andpassion of the BBR Network – remainsinstrumental in creating or reconfiguringsporting and entertainment venues in manycountries.

Now, as in ancient times, national or civicpride often finds expression in the designand construction of a stadium or arena – the

projects demand both architectural elegance andthe highest quality of functionality. BBR Technologyand know-how is ideally suited to the realization ofthese unique, flexible and durable structures – andcontinues to be applied in the creation of venuesfor many audiences around the globe.

WEMBLEY STADIUM,LONDON, UK

event along the length of the stadium – andthus the length of the Olympia stadiumbecame the standard for running tracks insubsequently built Greek and Roman stadia.The origin of the word ‘arena’ has, however, amore grisly origin – it comes from the Latinword for ‘sand’ which was used as a floorsurface in ancient arenas to absorb the blood

In the public arena

101CONNÆCT

POST-TENSIONED STADIASOLUTIONSPost-tensioning allows the construction ofimaginative yet practical forms and its use isparticularly relevant to stadium or arenaschemes. Recently, in the Polish city of Łódz,we created a ring beam – post-tensionedwith BBR CONA internal and externalsystems – to support the enormous dome-shaped roof of a new sports arena.When the newWembley Stadium was built,near London, UK, internal structural post-tensioning was a logical choice for thisimportant national venue.In this and previous editions of CONNAECT,you will already have read how BBR post-tensioning systems have contributed to therealization of the DY Patil Cricket Stadium inNavi Mumbai, India, the Arena Zagreb andthe Magic Box Athletic Complex in Madrid.However, perhaps the most unusual appli-cation, so far, for our BBR CONA internalpost-tensioning system has been in theconstruction of the five storey grandstand forthe Marina Bay Floating Stadium in Singapore– which also features the world’s largestfloating stage and football pitch.

CABLE-STAYED ROOFSStay cable technology opens the door on awhole new range of possibilities forarchitectural creativity, as well as functionalfeatures and considerations. Cable-stayedsolutions have been provided for arenas andstadia in Malaysia, Australia, Germany and theUnited Arab Emirates.For Penang Indoor Stadium in Georgetown,Malaysia, we designed and installed a stay

cable system, using BBR CONA stay cables,to support the trusses of the roof which hasa main span of 106 m.In 1981 and 1995, two Australian sportingfacilities were constructed with iconic staycabled roofs – the National Indoor SportsCentre in Canberra and the AthleticsCentre in Sydney. And, in 1982, for AbuDhabi’s National Day Parade Grandstand,we used BBR CONA stay cables tosupport the roof canopy.

HEAVY LIFTINGThe BBR Network also helps to provide animaginative and sustainable approach to theconstruction of stadia and arenas with the

use of heavy lifting techniques.These assistthe post-construction reconfiguring ofvenues such as Sydney’s Olympic Stadiumand the expansion of Bernabéu Stadium,home to one of the world’s most popularand glamorous football teams – Real Madrid.

MMR TECHNIQUESAnd finally, our range of MMR technologyand skills are applied to accommodaterenovations, modifications or changes of usewhich become necessary or desirable overtime. In the UK, our know-how has helpedto rejuvenate a world famous venue – theAll England LawnTennis & Croquet Club inWimbledon, UK. Before the new slidingroof could be installed over the famousCentre Court, beams needed strengtheningto accommodate the new loads whichwould be imposed on the structure.

LANDMARK STRUCTURESOn the following pages, BBR Networkmembers have provided detailed technicalinformation about their work on threestadia – in Sydney, Munich and Singapore –which continue to delight and proudlyserve the communities in which they stand.

�

BERNABÉU STADIUM, MADRID, SPAIN

MARINA BAY, SINGAPORELANDMARKSTRUCTURES

102 CONNÆCT

For the Olympic Games, the design brief and bidto the International Olympic Committee specifieda stadium capacity of 110,000 spectators –although the actual finished capacity was closer to115,000.To meet longer term requirements, such ashosting Rugby League, Rugby Union or Soccermatches – the stadium was initially designed withthe ability to be reconfigured into ‘Post OlympicMode’, seating approximately 80,000 spectators. Itwas important to allow for this reconfigurability atminimum initial cost, and still give the option of‘permanency’ in either situation.Construction and subsequent reconfiguration ofthe stadium was undertaken by Multiplex, withthe design by Sinclair Knight Merz (SKM).

RECONFIGURATION PROJECTThe stadium is generally a reinforced or post-tensioned structure and it is the facility toreconfigure after the initial purpose which makesit unique.The key feature is that, after the initialfield shrinking, the lower tiers of the East andWest Stands can be brought forward to betteraccommodate spectators for sports requiring arectangular field.The post-Olympic reconfiguration is a significantproject in its own right and was costed at around$80 million.

RELOCATING NORTH & SOUTH TIERSWe were engaged by Multiplex to slide sevenpost-tensioned pieces of the lower tiers forward

Stadium Australia – now renamed Telstra Stadium – was thecenterpiece of the Sydney 2000 Olympic Games. It is unique in thatit was designed and constructed to be reconfigured for smaller

crowd sizes after the Games – a move necessary to preserve atmosphereand intimacy of more local events. Mark Sinclair of Structural SystemsLimited outlines his company’s leading role in this pioneering scheme.

Green engineeringSTADIUM AUSTRALIA RECONFIGURATION, HOMEBUSH, NEW SOUTHWALES, AUSTRALIA

103CONNÆCT

by 15.575 m – there were four pieces eachweighing 2,000 t and three weighing 700 t.The lower tiers sit on a series of groundbeams, with supporting piles as required.Beam layout was such that, duringreconfiguration, the columns for each sectionto be slid would travel along these groundbeams.Where required, piles were located atthe initial and final position of any column. Ashort removable steel stub column wasincorporated at the base of each column –this was easily removed to allow substitutionof a sliding mechanism.The relatively smallfinancial outlay associated with theremovable column stub, foundations andbeams during the initial construction, allowedlater reconfiguration at a reasonable cost.To enable the fixed stand to slide, it had tobe released from adjoining structures andfrom its foundations. Minor pieces of thesemicircle at each end were removed – likeportions of a cake – so there would bespace available for the major pieces to fitback together after sliding forward andforming a tighter radius. A minor infill wascompleted after the sliding was finished.We developed a mechanism for this,borrowing heavily from the systems used toincrementally launch bridges.We completedfull design and analysis in-house.There wereseveral aspects to be resolved and the keyitems were:� Lifting and parking system� Sliding track� Sliding mechanism� Guidance system� Pulling mechanism� Column bracing. �

LANDMARK

STRUCTURES

Major stages of reconfiguration� Removal of the running track and long jump facilities.

� The playing field was then centered, as it had been off-centre becauseof the long jump facility.

� Removal of the temporary upper North and South Stands.

� Release and moving forward of the North and South Stand lower bowlsby 15.575 m.

� Construction of infill pieces between launched segments and behindthe new forward location.

� Demolition and rebuilding forward of the North and South Stand upperbowls by 15.575 m.

� Fitting of the moving tier system to the lower East and West Stands.These 100 m x 30 m stands can then be driven forward by 15.575 mdepending upon the code of football to be played. Reconfigurationtakes less than one day. Initially these stands were planned for a one-offmove in the same way as the north and south stands.

� Construction of a roof at the northern and southern ends, between thetwo main arches.

� Reinstatement of the external concourse on completion of allconstruction works.

104 CONNÆCT

The site works were undertaken within a verytight program and all seven launches werecompleted within a five week period betweenearly May 2001 and mid June 2001 – somefour weeks ahead of the critical programrequirements.

MOBILIZING EAST & WEST TIERSThe lower tiers of the East andWest Standsare required to move 15.575 m forward for‘NRL’ football games from their home ‘AFL’position.This was to be a world first – wherea permanent concrete structure was to bemade mobile at the push of a button.During the initial stadium construction, amovement system for these stands had beendeveloped. Multiplex enlisted StructuralSystems to project manage, procure andinstall the moving tier systems without anydesign or costings – with only about fivemonths to complete the works.Each stand is approximately 31 m deep, 10 mhigh, 100 m long, weighs around 2,500 t andseats 7,500 spectators. Design developmentprogressed, based on some original concepts,but now required a full design to becompleted.A very close relationship formedbetween Multiplex, SKM and StructuralSystems.In turn, specialist subcontractors wereengaged to manufacture the bogie system,

105CONNÆCT

provide the necessary operational controlsand install considerable structural steelwork.Eilbeck Cranes, Control Techniques andAllmen Industries formed the core of externalsuppliers to the project, with StructuralSystems undertaking installation of the rail andbogie systems.The team succeeded in achieving all of thedeadlines set – proving their abilities anddedication to the project.

TECHNICAL OVERVIEWBoth tiers are effectively identical except thattheWest Stand incorporates a players’ entrytunnel and underneath, on Level 0, it hasvarious players’ rooms.There are 14 almostidentical raking beams which are supported inthree places and where a temporary leg isinstalled to cater for live load.On Level 0, there are two columns, SC1 andSC2, where a single rail carries a tandemwheeled bogie – SC2 being powered. OnLevel 1, a single axle, twin wheel bogie (SC3)runs on a pair of rails. In the forward position,this bogie straddles the recess for the rakerbeam when in the rear position.The stands’ live load is transmitted throughtemporary props,TP1 (long prop) in theforward NRL position andTP2 (short prop)when in AFL position.A hydraulic jack hasbeen incorporated in the base of each prop.Earthquake resistance is provided at Level 0by lateral restraints in bays 7 & 8 andlongitudinal reaction through bays 2 & 13.When in the forward NRL position, threedrop-in temporary bridges permit accessfrom the Level 2 members’ facilities to the topof the tier.When in AFL mode, these bridgesretract, fold and store against the underside ofthe level 3 overhanging roof.The stands have a steel-framed carriage –added since the Olympics – to the entirelength.These front nine rows of seats are fixedto the moving concrete stands and travel in-and-out accordingly.

Preparing the stands for moving requires asignificant number of activities but, in generalterms, just a relatively small crew canreconfigure the stands in approximately eighthours.While the use of concrete in structures iswell-documented, normally structures arefixed with no intention of having them movearound.The entire lower tier at StadiumAustralia was initially conceived and built toallow for later transpositioning.The lower tiers of the North and SouthStands were moved in a one-off operation,while those on the East andWest Stands havebeen configured to move in or out, requiringonly a few people and taking a relatively shortperiod of time.The technology incorporated into theconstruction, manufacture and control systemsenable a brittle and heavy structure to begently relocated without damage or difficulty.The integration of the technology applied inthis instance to a concrete structure is uniqueand provides the spectators with the bestpossible seating arrangement, regardless of thetype of sport to be played.This stadium is a perfect example of howinnovative and timely engineeringcollaboration can adapt structures to performaltered functions, ensuring longevity, value formoney and reduced environmental impact. �

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Transformation process� Removal of tray sections of grass,called sod pans, to expose rails intrenches which are below grasslevel.

� Securing of barriers, closing someaccess ways, releasing props,removal of earthquake systems.Removing temporary infill sections.

� Checking of electronics, verificationof ‘safe to proceed’.

� Moving stand, operating rollershutters at mid-distance.

� Making safe for access, securingagainst earthquake, setting props,fitting three Members’ Bar Level 2bridges. Shut down drive system.

106 CONNÆCT

The concept was developed from thewinning entry in a design competition whichaccommodated all the individual areas forthe various sports under a single lightweight,transparent roof – forming an aestheticallypleasing canopy over the whole venue.

DESIGN CHALLENGEThe design challenge was to create a75,000 m² roof which featured large column-free spaces. Architects Behnisch & Partner,Frei Otto and engineers Leonhardt & Andrämet this challenge by presenting a post-tensioned cable-net construction – whichwas unrivaled in meeting all requirements.Skillful management of the pre-stressingforces achieved a perfect adaptation of theshape of the Olympic roof to therequirements of the architect and the siteconditions – its flexibility being superior toother construction methods.

ADVANTAGES OF PT CABLE-NETSTRUCTURESPost-tensioned cable-net structures haveadvantages over other types of constructionwhere long spans are required while allowingsufficient build height for substantialcurvatures of the net surface and where fallsplanes can be designed such that the cabletension does not have to be increasedconsiderably to compensate for an extensivesag of the net structure.So, a post-tensioned cable-net construction isthe perfect solution for producing long freecable lengths and where column-free spaceor structural transparency is important.

FIRST FOR BBR HIAMFor the first time, the newly developed 0.6”diameter BBR High-Amplitude fatigueresistant parallel strand stay cable systemwas used for the 244 main stay cablescarrying the roof structure.To keep the sag and, hence thedeformations, to a minimum, the designershad specified parallel strand cables for the244 main stay cables in place of locked coilcables. Parallel strand and wire cables havesignificant higher moduli of elasticity incomparison to locked coil cables.This has afavorable effect on the deformationbehavior of cable-stayed structures – and,in some cases, the realization of thesestructures even depends upon it.In spite of the great number of main staycables, the designers were able to get bywith just four different cable types, having31, 55, 85 and 109 single 0.6” diameterstrands per cable. As a result of thedifferent cable lengths – between 4.5 mand 129 m – and also of the differentanchorage types, a great variety of cable

types had to be manufactured, thus hardlyany two cables were identical.

ANCHORAGEThe patent-protected HiAm anchoragesystem was developed in collaboration withthe consulting engineers Prof. F. Leonhardand Dr.W. Andrä, Lechler Chemie and BBRHeadquarters.The ends of the strand bundle are fitted withBBRV button heads and are anchored in asteel cylinder with a conical inner surface, inwhich the cavities are filled under vibrationwith epoxy mortar, small steel balls and zincdust, whereupon this filler material is curedby heating.When adequately dimensioned,this anchorage type reaches not only thestatical but also the dynamic resistance of thebasic wire or strand material – which forcable-stayed structures is of particulareconomical relevance. In addition, thisanchorage type possesses matchlesscorrosion protection in the anchorage zone.

Pioneeringroof construction

The roof of the stadium built in Munich for the 1972 OlympicGames saw the first large scale application of the thennewly-developed BBR High-Amplitude (HiAm) parallel

strand stay cable system.The structure has now been a landmarkon the Bavarian skyline for approaching 40 years.

107CONNÆCT

LANDMARK LARGE SCALE TESTINGThe first large scale tests on cables equippedwith BBR HiAm anchorages were executedat the Otto-Graf Institute in Stuttgart.Meantime, within a surprisingly short time,the Federal Swiss Laboratory EMPA hadinstalled a facility for the dynamic testing oflarge size stay cables. It was a landmark in

the history of testing technology because thisnew test facility made it possible, for the firsttime, to achieve maximum loads of 6,700 kNand amplitudes of up to 2,500 kN.

CONSTRUCTION ASPECTSThe cable-net has square meshes withjunction point distances of 750 mm.With its

flexible nodes, the net can be easily adjusted– like a folding grille – while laying on theground.For the roof of the Olympic Stadium a totallength of approximately 400 km of rope wasneeded.Whilst these ropes needed to beflexible for the installation and thereforemade out of thin wires, they also needed �

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OLYMPIC STADIUM ROOF,MUNICH, GERMANY

Photograph courtesy of Kevin Lazarz

108 CONNÆCT

to be rather thick-wired for improvedcorrosion behavior.The first choice for the cable-net was a19-wire strand with thick galvanized wires,with diameters of 2.3 and 3.4 mm.Withthese features, the net has a double safetyfactor against rupture and can carryservice loads of 150 kN/m.

ERECTION OF STRUCTUREAfter the foundations had beencompleted, first the high pylons wereerected and then the complete netconstruction including boundary cables,strand bundles and small masts wereassembled on the ground for eachportion of the roof.After that, all junction points were hauledto their final positions by means of thehang-up cables and anchoring cables orwere superimposed directly on thesupport pylons. During this process, allmovements had to be carried out atequal distances from the geometricalcentre of the roof.After all anchoring cables had reachedtheir final position in the foundations, the

position of all junction points and markednodes – as well as the tension in the netropes, anchoring cables and pylons – wasmeasured.When major tension variationswere observed, corrections were made tothe rope length at the turn buckles andanchoring cable anchorages. As a rule,variations in the tension of +/-15% weretolerated – provided that it could bedemonstrated with an additional staticalcomputation that this was acceptable interms of structural stability.After erection, it was clear that the effortsof the exact cutting and the precisefabrication were worthwhile, because onlya few corrective measures were neededto bring the roof into its planned position.

�

“THE EXACT CUTTINGANDTHE PRECISEFABRICATIONWERE

WORTHWHILE, BECAUSEONLY A FEW CORRECTIVEMEASURESWERE NEEDEDTO BRINGTHE ROOF INTOITS PLANNED POSITION”.

In 1992, the Yishun Stadiumopened its doors and washost to the karate event

during the 1993 SEA Games inSingapore. Since then, it hasserved as home ground for anumber of football clubs. Thespectator experience is en-hanced by the cable-stayed roof.

In the northern part of Singapore, at the endstation of the rapid transit line Singapore –Yishun, a new sports complex was erectedconsisting of an indoor and an outdoor stadium.Great importance was placed on aestheticquality in the design of the sports complex, thusthe architect decided to use a cable-stayed roofdesign.All three roofs, although different in size, weredesigned according to the same structuralconcept – a rectangular grid of space trussessuspended by stay cables.Of the three, the most demanding from thestatics point of view was the big roof for theindoor stadium because it had the longestcantilever length of 39.2 m.

109CONNÆCT

One of the main considerations was thebehavior of the structure under windconditions. In order to reduce the uplift dueto wind to a tolerable margin under serviceconditions, tie-down members in the form ofsteel tubes had to be provided underneaththe roof structure.The roof is held in placeby the suspension cables, which transfer theloads to the top of the pylon.The back staycables, which are in balance with thesuspension cables, transfer the forces downto the massive counterweight foundations.The size of the BBR CONA stay cables varies

from 0306 to 1906 strands, each with adiameter of 15.2 mm. Great care had to begiven to corrosion protection.The tendonsconsist of individually polyethylene coatedstrands in high density polyethylene ductswhich are cement grouted after finalinstallation.The anchorages are designed in such a waythat the cables can be readjusted or even bereplaced at any time.All stay cables are hinge-connected by means of 200 mm diametersteel pins.The design of the pylon was straight-forward.With a length of 22.77 m and a hinge at thebottom, the pylon is a pure compressionmember – bending due to wind is negligible.The apex on top of the pylon transfers theforces of the front to the back stay cables.The apex consists of a cast iron cone withradially welded fin plates.Steel A-frames form the main supportsunderneath the rear part of the roof.Theyare hinge-connected to the lower ends of thepylons by a 400 mm diameter stainless steelpin.The pins transfer the large loads on the

pylon down to the foundation and providelateral and longitudinal stability of thestructure.The steel structure was erected on scaffoldsin a pre-cambered position so that thecorrect level was reached upon completingthe stressing operations. All cables wereprecisely pre-adjusted after the installation insuch a way that the whole stressingoperation could be done at the loweranchorages of the back stay cables only. �

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AESTHETICALLY ENHANCED VIEW

Yishun Stadium roof data� Outdoor stadium roof – 120 x 30 m= 3,600 m2, supported by staycables from 5 masts

� Indoor stadium big roof – 67.5 x39.2 m = 2,646 m2, supported bystay cables from 4 masts

� Indoor stadium small roof – 97.5 x25 m = 2,438 m2, supported by staycables from 3 masts

110 CONNÆCT110 CONNÆCT

SWITZERLANDBBR VT International LtdBahnstrasse 238603 Schwerzenbach (ZH)

Tel +41 44 806 80 60Fax +41 44 806 80 50

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EASTERN CANADACanadian bbr Inc.3450 Midland Ave.ScarboroughOntario M1V 4V4

Tel +1 416 291 1618Fax +1 416 291 9960

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AUSTRIAVORSPANN-TECHNIKGmbH & Co. KGSchillerstrasse 255020 Salzburg

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GERMANYVORSPANN-TECHNIK GmbHFürstenrieder Strasse 27581377 München

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Spankern GmbH (North)Lübecker Strasse 53-6339124 Magdeburg

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MONTENEGROsee Croatia

NETHERLANDSSpanstaal B.V.Koningsweg 283762 EC SoestPost Address:PO Box 3863760 AJ Soest

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EUROPEHEADQUARTERS

AMERICA

Additional BBR technology licenseshave been granted in Europe, AsiaPacific and America – for moreinformation, please contact the BBRheadquarters.

BBRDIRECTORY

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NORWAYKB Spennteknikk ASSiva Industrial EstateN. Strandsveg 19-21Postboks 12132206 Kongsvinger

Tel +47 62 81 00 30Fax +47 62 81 00 55

[email protected]

POLANDBBR Polska Sp. z o.o.ul. Marywilska 38/4003-228Warszawa

Tel +48 22 811 50 53Fax +48 22 614 57 60(ext. 108)

[email protected]

BBR Polska Sp. z o.o.ul.Tarnogorska 214a44-105 Gliwice

Tel +48 32 33 02 410Fax +48 23 33 02 411

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PORTUGALsee Spain

ROMANIAsee Spain

RUSSIAsee Austria

SERBIAsee Croatia

SLOVAKIAsee Austria

SLOVENIAsee Croatia

SPAINBBR Pretensadosy Técnicas Especiales, S.L.Antigua Carretera N-IIIKm. 31, 15028500 Arganda del Rey, Madrid

Tel +34 91 876 09 00Fax +34 91 876 09 01

[email protected]

SWEDENSpännteknik ABBox 158671 24 Arvika

Tel +46 570 126 60Fax +46 570 109 50

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UKRAINEsee Poland

UNITED KINGDOMStructural Systems (UK) Ltd12 Collett WayGreatWestern Industrial EstateSouthallMiddlesexUB2 4SE

Tel +44 20 8843 6500Fax +44 20 8843 6509

[email protected]

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BAHRAINsee United Arab Emirates

IRAQSpezialized Prestressing CoKarrada, Dist. 901, St. 1, Bldg. 16Office No. 10Baghdad

Tel +964 1 718 6333Fax +964 1 718 1385

[email protected]

JORDANMarwan Alkurdi & PartnersCo. LtdPO Box 506Amman 11821

Tel +962 6 581 9489Fax +962 6 581 9488

[email protected]

OMANsee United Arab Emirates

QATARsee United Arab Emirates

KINDGOM OFSAUDI ARABIAHuta-Hegerfeld Saudia LtdBBR Prestressing DivisionPrince Sultan St. Lotus BuildingPO Box 1830Jeddah 21441

Tel +966 2 662 3205Fax +966 2 683 1838

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SOUTHAFRICAStructural Systems (Africa)Block B, 60 Civin DrivePellmeadow Office ParkBedfordview, Johannesburg 2008Tel +27 11 409 6700Fax +27 11 409 6789

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UNITEDARABEMIRATESNASA (BBR) StructuralSystemsLLCHead Office, Suite #302PO Box 28987Sara Building, GarhoudDubai

Tel +971 4 2828 595Fax +971 4 2828 386

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INDIABBR (India) Pvt LtdNo. 318, 15th Cross,6th MainSadashivanagarBangalore – 560 080

Tel +91 80 4025 0000Fax +91 80 4025 0001

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JAPANJapan BBR Bureauc/o P.S. Mitsubishi ConstructionCo. LtdHarumi Center Bldg. 3F2-5-24 Chuo-kuTokyo

Tel +81 3 6385 8021Fax +81 3 3536 6937

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AFRICA

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PHILIPPINESBBR Philippines CorporationSuite 502, 7 East Capitol BuildingNo.7 East Capitol DriveBarangay KapitolyoPasig City 1603Metro Manila

Tel +63 2 638 7261Fax +63 2 638 7260

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SINGAPOREBBR Construction SystemsPte LtdBBR Building50 Changi South Street ISingapore 486126Republic of Singapore

Tel +65 6546 2280Fax +65 6546 2268

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TAIWANTest Posttensioning – ETIC05F-2, 95, SEC 3Roosevelt RoadTaipei

Tel +886 2 2367 6486Fax +886 2 2367 6487

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THAILANDSiam-BBR Co Ltd942/137.1 5th FloorCharn Issara TowerRama 4 RoadKwaeng Suriwongse, Bangrak10500 Bangkok

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VIETNAMsee Singapore

AUSTRALIAStructural Systems (Northern)Pty Ltd20 Hilly Street, MortlakeNew SouthWales 2137

Tel +61 2 8767 6200Fax +61 2 8767 6299

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Structural Systems (Northern)Pty LtdUnit 1, 12 Commerce CircuitYatala, QLD 4207

Tel +61 7 3442 3500Fax +61 7 3442 3555

www.structuralsystems.com.au

Structural Systems (Southern)Pty LtdPO Box 1303112 Munro StreetSouth MelbourneVictoria 3205

Tel +61 3 9296 8100Fax +61 3 9646 7133

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Structural Systems (Western)Pty Ltd24 Hines Road, O’ConnorWestern Australia 6163

Tel +61 8 9267 5400Fax +61 8 9331 4511

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FIJIsee New Zealand

NEW ZEALANDBBR Contech6 Neil Park Drive, East TamakiPO Box 51-391PakurangaAuckland 2140

Tel +64 9 274 9259Fax +64 9 274 5258

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BBR Contech38Waione Street, PetonePO Box 30-854Lower HuttWellington 5040

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BBR Contech7A Birmingham DriveMiddletonPO Box 8939RiccartonChristchurch 8440

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BBRDIRECTORY

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