I S S U E O N E 1 9 9 9

Kisosansen bridge, Japan

8

15

PT of the

Madero Este

Complex

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E D I T O R I A L

4-5Wadi Leban Bridge,

a new reference in cable-stayed bridges

10-14Your Specialist Contractor

in Heavy Lifting

VSL International Ltd.Bernstrasse 9, 3421 LyssachSwitzerland andVSL Management 41, avenue du Centre78067 St-Quentin-en-YvelinesFrance

Editor: A. Le PivertTel: +33 1 30 12 09 30

Technical Editor: H. R. GanzTel: +33 1 30 12 09 30

Regional Editors:G. Pash - Australia and PacificTel: +61 2 9484 59 44

J-P. Trin - South East AsiaTel: +33 1 30 12 09 42

A. Payne - North East AsiaTel: +852 2590 22 22

H. Wlodkowski - Central EastEurope and Middle EastTel: +41 34 447 99 11

P. Bron - Western Europe, Africaand Latin AmericaTel: +33 1 69 19 43 00

Coordination:S. AlezrahTel: +33 1 30 12 09 41

Design:Red LineTel: +33 1 41 14 01 80

Linguistic Consultant:N. HargreavesTel: +33 1 43 66 88 05

P U B L I S H E D B Y

Structural repairs, a new and

developing market

In many industrialised countries, emphasis is shifting

towards preserving or modifying

structures rather than demolishing them and

then rebuilding.

Far from being dictated by fashion, this

approach is based on sound reasoning:

Modern technologies and products now allow

us to repair or modify structures at a reasonable cost.

In the past, they would simply have been

demolished.

The construction of new infrastructures in

densely populated areas is subject to a great

many environmental and political constraints. It is now

sometimes easier to upgrade existing structures than

build new ones.

Old structures and buildings are now perceived

by the public as a valuable heritage that should

be passed down to future generations in a good state

of repair.

If one adds the maintenance of industrial

buildings and installations to the above, it is

clear that there is a vast potential market.

A Group like ours, with its understanding of and

experience in sophisticated construction

technologies - from design through to

construction -, has a vital and increasing role to

play in this field.

As only a small percentage of our turnover

currently relates to this activity, we have a great

margin for growth and our increasing

involvement represents an excellent complement

to the Groups current scope of works.

Alain Le PivertCEO and Chairman of the Board

VSL in Mexico, a young and

successful profit centre

H I G H L I G H T S

H E A V Y L I F T I N G

SPECIAL

Completion of the

Princess Alexandra

Hospital

9

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B R I D G E S

supply and install the externaltendons. Each of the 24 cablesconsists of nineteen 0.6" strands withlengths varying from 218 m to 230 m,representing a total nominal breakingload of about 85,000 kN. The 4 cables in 2 boxes were alwaysstressed simultaneously. This resultedin a mid-span lift of between 100 mmand 110 mm, being very close to whathad been predicted by the engineers.Works began at the end of 1998 andwere completed in spring 1999.

Franz Fischl iVSL Switzer land

BTS is a project awarded to theSiemens-ITD Consortium in 1995 to construct the elevated light railtransport system in Bangkok. ITD,a long-standing client of VSLThailand, was awarded thecontract for the civil works. Itsubsequently subcontracted thefollowing works to VSL:: design & equipment supply foroverhead erection truss (designedby VSL Technical Center Europe); PT for spans, precast segments,piers & portals; equipment for underslungerection trusses; pier formwork design; overhead truss segment erection; underslung truss segment erection.The total distance of the project is 25.5 km, representing 925 decksconsisting of 8,052 precast segments.VSL was awarded the subcontract for464 decks, representing 4,092 precastsegments and 4,800 t of PT.

The 27-year old Black Forest HighwayBridge (Schwarzwaldbrcke) over theriver Rhine is one of the mostimportant bridges in Basle, linkingSwitzerland, Germany and France. Asthe 233-m long and 48-m widebalanced cantilever bridge with 4 box

girders had deflected beyondacceptable limits at its mid-span, the structure required majorrenovation works.These works were based on a designby Schmidt & Partner. The main contractor chose VSL to

Simultaneous post- tensioning

in progress

- S W I T Z E R L A N D - R E P A I R T O T H E S C H W A R Z W A L D B R C K E

Segmental erection works byunderslung truss, overhead truss, aswell as longitudinal PT stressing werecompleted by the end of January 1999and, by the end of February, VSL hadcompleted approximately 98% of theoverall works. The only remaining PT

work on station E9 wascompleted in March.The trains trial run took place atthe end of October 1998, andhas been successfully operatingsince then. The ceremonial opening of thesystem is expected to take placeon 5th December 1999, tocelebrate His Majesty the Kings72nd birthday.

Narenn Jinruang and Likhasit Ki t t isartra

VSL Thai land

- T H A I L A N D -C O M P L E T I O N O F T H E B A N G K O K M A S S T R A N S I T S Y S T E M

Overal l v iew of Black Forest Br idge

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B R I D G E S

The Wadi Leban bridge forms part ofthe section "B" works for theextension to the southern part of theRiyadh Ring road, and represents anoverall length of 1.5 km.Crossing the Wadi Leban valley, this763-m long cable-stayed bridge is split into three spans (179 m 405 m 179 m). The bridge deck is 80 mabove ground level and the towersrise 90 m over the deck level. Thebridge has an overall width of 35.8 mand comprises two 13.95-m widecarriageways with a 5.4-m medianstrip that incorporates the stays.With its towers rising to 167.5 m to thenorth and 175.5 m to the south, theWadi Leban cable-stayed bridge is aparticularly impressive sight, whichcan be seen from most of Riyadh. Theoriginal concrete design for the bridgewas carried out by Dar al Handasahand the bridge was constructed by theTanmia/Saudi Archirodon joint venture.

construction engineering analysis,methods and work procedures,supervision during fabrication, erection,stressing and grouting of the stays.

The VSL 200 stay cables, varying insize from 6-19 to 6-52 and in lengthfrom 87 m to 435 m, were allfabricated on site. They were lifted and continuously installed fromanchorage to anchorage and passedthrough the pylon inside saddledeviators, which were pre-groutedbefore the required load wasintroduced.

View of the 763-m long cable-stayed br idge crossing the Wadi Leban val ley

Overa l l drawing of the cable-s tayed br idge

- K I N G D O M O F

Construct ion of br idge deck, located

80 m above ground levelThe bridge deck is a three-cell boxsection, with a central trapezoid celland two triangular side cells. Thebridge deck is precast as a singlesection, with the exception of the mid-span closure and the end diaphragms.

The precast segments (35 m wide and3 m long; 185 t to 250 t) were matchcast using the short line method anderected using the balanced cantilevermethod. All transversal andlongitudinal PT was supplied by VSL.As the site is located in the SaudiArabian desert, exceptional climaticconditions had to be taken intoconsideration during all constructionstages. The thermal conditions rangedfrom 2C up to +55C over the year,and from +20C to +55C over 24 hours during summertime.

The scope of VSL CEME and VSLTCEU works included the design andsupply of post-tensioning and stays,

With its towers rising to 167.5 m to the north and

175.5 m to the south, the Wadi Leban cable-stayed

bridge is a particularlyimpressive sight, which can

be seen from most of Riyadh

Wadi Leban cab

Grouting of the stays began mid-April and was completed by the first week of June 1999.

Pel le GustafssonVSL CEME

The last stay was installed in lateNovember 1998 and the final tuning ofthe stays was completed by April 1999. Due to the use of a highly innovativejack manipulator, the final tuning ofthe 248 stays using 4 nos. of ZPE 1000, was carried out in a record6 days, representing an average of 41 stays per day.The construction method with erection of fully fabricated staysproved that, in some cases, it ispossible to be fully competitive with asingle strand installation. Regular 4-day cycles and two 3-day cycles wereachieved during construction

B R I D G E S

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By using a tailor-made winch system,the stand-bundles weresimultaneously pulled in pairs fromthe fabrication table at the bottom ofthe Wadi floor up to the edge of themain span segment. The stays werethen deviated into the pre-installedstay-pipes on the main span side,pulled up through the HDPE pipe, thenthrough the pylon inside the saddlepipes and down through the stay pipeon the side span side. The anchorageassembly was then carried out on thebridge deck after which the four stayswere simultaneously pulled into theguide-pipe using four nos. of SLU-40.A novel feature of the saddle stays isthe use of a flexible grout (softrubber) at the saddle entrance withthe remainder being filled, as usual,with rapid strength cement grout.Because of its flexibility, the grout isable to accept the cable sag variationsduring the stressing and groutingstages.

Wadi Leban normal cycle of construction:

erection of 2 concrete bridgesegments, which were lifted fromthe bottom of the Wadi up to thebridge cantilever (+80 m), thenglued and stressed to t