pbl group newsletter - · pdf filewas detected. on superimposing the for-construction piling...

was detected.

On superimposing the For-Construction Piling Layout drawing over its correspond-ing As-built, the Design Engi-neer noted deviations of 200 mm – 500 mm. Simply put, the piles had displaced!

Significance of Discrepancy It was imperative that conse-quences of this deviation be evaluated without further ado. Structural analysis indi-cated that the resulting ec-centricity due to this devia-tion had contributed to ex-cessive moments and loads. An overload on pile capacity

Situated in the heart of Bangkok, the Asia Center, once completed, is expected to mark Architectural and Structural history, with its free standing columns origi-nating at the Ground Floor all the way to the eighth

floor. Currently under con-struction, the Project is wit-nessing thorough design and construction supervision by all involved parties, ranging from the Client to the Con-tractor. Project Manage-ment’s rudiments of time, cost and quality are focused un-der the spotlight at all times. The Role of the Structural Design Engineer Serving as the Structural De-signer and PT Specialist, PBL Group takes responsibility in design, review and approval of all construction drawings prior to construction. During the course of review of such drawings, and in particular, the blue print of the As-built Piling Layout, a discrepancy

PT Put to Test

Asia Center Project Site

Look out for the up-coming publication • LATEST PT DESIGN TECH-

NOLOGIES

• SEMINARS AND WORK-

SHOPS

• STATE-OF-THE-ART DESIGNS

• NEWS AND EVENTS FROM GLOBAL PARTNERS

• UPDATES AND FOLLOW-UPS FROM THIS ISSUE

• PBL SOCIAL EVENTS

PT BARS PUT TO TEST 1

PT ANCHOR BARS ON SITE

3

THE STRENGTH OF THE MONO-STRAND TENDONS

4

STEPPING INTO THE LAND OF THE THUNDER DRAGON

5

CROSSING THE RIVERS 7

JORDAN COMES TO THAILAND

8

Inside this issue:

September 07 Volume 1, Issue 3

T H E S T R E N G T H Y O U C A N T R U S T

PBL GROUP NEWSLETTER

Message from the Editor ture touring but rather, was honored to support the Royal Government of Bhutan in developing its road networks through bridges.

And finally, as the year 2007 gradually draws to an end, on behalf of PBL Group and its partners, I wish all our readers a successful wrap-up of this year’s business opera-tions.

Do keep a look out for the December edition of the Newsletter. It promises to be exciting as ever with quick peek to 2008.

Nadeera Rangika

Editor

Dear Readers,

Once again, another issue straight out from the oven!

This time around, the leading hot topic is our latest appli-cation of PT Bars at the re-nown Asia Center project currently under way at Sathorn in Bangkok.

I am honored to be announc-ing that this latest PT design technology by PBL, which has now been applied success-fully, will be incorporated in PBL’s portfolio to be used in future structural strengthen-ing.

The Asia Center project I must admit, is a personal

favorite of mine just as it would be any Architect’s dream-come-true and any Structural Engineers greatest challenge. Mind you, the project, featured twice in this issue, shall again be revisited in the next issue.

Going beyond Bangkok, we step onto the Himalayan Mountains in the Kingdom of Bhutan! Yes, Bhutan! Land-locked between India and the People’s Republic of China, Bhutan is a potpourri wonderland of glaciated mountain peaks dense, de-ciduous forests and alluvial lowland river valleys. How-ever, PBL didn't go adven-

(continued on Page 2)

Sathon Road

of almost 50% was noted on some piles.

Resolution of Crisis: In order to eliminate the resulting excessive loads and moments, it was pro-posed that counter moments be induced through custom-ized PT bars, installed in the adversely affected footings and stressed accordingly.

As such, based on analysis, four (4) footings were to be strengthened with counter moments of the PT bars. Two layouts: one layout with 3 DB 32 PT bars and another layout with 5 DB 32 PT bars

were proposed. Illustrations are as shown below. A total of 48 PT Anchor bars were required.

As illustrated in the sche-matic drawing below, one set comprises of the Steel Plate to act as an interface of load transfer to the foot-ing during stressing, the Spi-ral Reinforcement is used to resist the anti-bursting stress developed under the steel plate at the time of stress-ing, and a trumpet to serve as a guide during installa-

tion. A grout vent is also provided as required.

Installation: During the course of installation, the unanticipated issue of con-gestion was a cause for con-cern. Thus, all obstructing reinforcement were bent in into the pile cap and sup-plementary reinforcement were provided thereafter.

Stressing: Burapha Steel, the manufacturer of the PT Bars used Hydraulic Jack of 100 Ton capacity to stress the PT bars to a maximum of 25 Tons, in line with PBL’s design guidelines and super-vision.

Grouting: Grouting was carried out upon the com-pletion of stressing.

… PT Put to Test


Three piles strengthened using PT Bars at Footing

F1 with Main Column C1 ⇓ and ⇒

Contributed by Ms. Nadeera Rangika, who is currently the Projects Engineer at the International Operations Office of PBL Group Ltd.

Moment due to eccentricity

PT Bars inducing

P

W

counter force

Webetween Column and Pile c.g.

Px Counter Momentdue to PT Bar force

Increase in pile loadsdue to eccentricity moments

Schematic Drawing of PT Anchor Bar

Set-up of the Stressing End

Volume 1, Issue 3

The following photographs below illustrate the steps of the application of PT Anchor Bars:

PT Anchor Bars on Site

PT Anchor bars centered and embedded in affected piles

PT Anchor bars within the cage of footing reinforcement

Reinforcement, bent in due to congestion

Supplementary reinforcement added prior to concrete casting

Awaiting Stressing

Stressing in Progress

Completed Stressing and Grouting

In preparation for Grouting

The Strength of the Mono-strand Tendons


“ …. THE MOST

PRACTICAL AND

FUNCTIONAL

WITHIN THIN

SLABS AS THEY

EFFORTLESSLY

ACCOMMODATE

… “

The bonded mono-strand tendons were first intro-duced into the Thai construc-tion industry by PBL Group to meet the demands of cost and quality in PT works. A case in point is the Shrews-bury International School, highlighting the extensive slab-on-ground finished with minuscule mosaic tiles, which till today, 4 years later, still remains un-deformed.

Moving on from South East Asia, PBL Group took the bonded mono-strand ten-dons further out to the Mid-dle East. Given the high level of precision stipulated on a Tennis Court floor, the mono-strand tendons be-came an immense success at two (2) of the Tennis Courts built at the Ministry of Public Health, at the Hamad Medi-cal City in Doha, Qatar.

Following these two success stories, PBL Group took this system to a broader level and has thus far, applied it to majority of the projects within the Bangkok Metro-politan. Ranging from small, medium and large buildings, the system has recorded high demand and client-contractor satisfaction.

The following are some of the advantages leading to the satisfactory responses from all parties:

⇒ The system is the most practical and functional within thin slabs as they effortlessly accommo-date the bonded mono-

strand tendons. On the other hand, the flat ducts with 3, 4 or 5 tendons occupy greater space and consequently, the profile tends to be too shallow.

⇒ The system is best used at intermediate stressing joints, wherein the ten-dons are placed continu-ously through the joint with intermediate stress-ing at the joint, upon concreting of one adja-cent slab.

⇒ The system allows for detailing the tendon spacing at 8 times the slab thickness, which is the governing service-ability criterion for crack control. With the flat duct systems, there may be requirement for provision of more number of strands than required for s e r v i ceab i l i t y and strength. For short to me-dium (4.0 – 6.0 m) spanned slabs, it is rather uneconomical to design as a traditional flat duct systems, given the nature of the tendons and de-tailing criteria. However, it is also suitable for long spans, as it is the case with the Empire Tower Project in Bangkok.

⇒ There is less friction within any particular duct as each strand is con-tained in individual ducts, unlike in the flat duct system, where there is friction against the sur-faces of each adjacent strand. Consequently, the coefficient of friction can be as low as 0.15 - 0.18 whereas the value is 0.25 otherwise.

⇒ With the mono-strand tendons, there is no an-chorage friction devel-oped at the time of the stressing as each strand projects out individually from the anchorage with-out any deviation. Con-versely, with the flat duct system, 3, 4 or 5 strands contained within the same duct spreads out as it contacts the wedge, thus producing anchor-age friction.

⇒ There is equally devel-oped bond strength as the flat duct system, and in addition, corrosion protection is also en-sured.

The following are project references where the bonded mono-strand ten-dons have been successfully installed:

♦ Arun Ammarin Apart-ments: 5 floors with 6 m max. span and 150 mm thk. Slabs.

Detail at intermediate stressing joint

Mono-strand Tendons at Asia Center

1 Strand within 1 Duct

Mono-strand Tendons passing through congested reinforcement

Ideal 24


Small but mighty!

“… EQUALLY

DEVELOPED BOND

STRENGTH AS THE

FLAT DUCT

SYSTEM…

CORROSION

PROTECTION...”

Volume 1, Issue 3

“A SPAN OF

78.60 M.. + 8

NOS.

ANCHORAGE

TYPE M1206.. +

80 NOS.

ANCHORAGE

TYPE SF206... ”

♦ Muang Ake Apartments: 5 floors with 6 m max. span and 180 mm thk. slabs.

♦ The Log, Sukhumvit 101: 8 floors with 6 m max. span and 150 mm thk. slabs.

♦ Rongmueang Residential 16 floors: 6 m max. span

and 150 mm thk. slabs

♦ Ideal 24: 41 floors with 10 m max. span and 250 mm thk. Slabs

♦ Empire Place: 45 floors with 9 m max. span and 190 - 220 mm thk. slabs.

♦ Asia Center Parking: 8 floors with 12 m max. span and 300 mm thk.

… mono-strands.

slabs.

In summary, the bonded mono-strand tendon system has been favorably ac-cepted by the Architect for its slenderness, by the Engi-neer for its strength, and by the Owners for inherent fi-nancial savings.

C o n t r i b u t e d b y M r . Kritchaiprasert Worapongwasu, the Operations Manager at PBL

Nestled in the Eastern Hi-malayas, the magnificent Kingdom of Bhutan is situ-ated at approximately over 3000 m above the mean sea level in most regions. Thus far, communication over bridges has facilitated in easing the lives of the Bhu-tanese. The country, with their beloved King Jigme Khesar Namgyal Wang-chuck of not only the Bhutan-ese but also many Thai peo-ple, received assistance from the Government of Japan through JICA in order to develop communication infrastructure.

PBL is proud to participate in this development by sup-plying and supervising some of the PT works of the bridges therein. The first bridge at its capital city, Thimphuchu was funded by it owner, the Royal Govern-

ment of Bhutan obtained Technical Support from the Japan International Coop-eration Agency (JICA). Other involved parties in-clude:

Designer: Slaich Bergerman Consultantcy

Supervision: Green Place & Acecoms, AIT Joint-Venture

Contractor: Gaseb, Bhutan & Simplex, India Joint-Venture

With a span of 78.60 m, Steel Arch structure with PT slab contained 0.6” strands with 8 Anchorage Type M1206 in its beams and 80 Anchorage Type SF 206

Stepping into the Land of the Thunder Dragon!

Map of Bhutan

Topographic Map of Bhutan

Thimphu Bridge under construction

The Rising Empire Place

in the entire slab. A total quantity of 11 tons of strands were installed therein.


Similarly, the Semtokha-Rongchu Bridge, owned and funded by the Royal Gov-ernment of Bhutan obtained Technical Support from the Japan International Coop-eration Agency (JICA). How-ever, the following parties were involved therein:

Designer: Green Place & Acecoms, AIT Joint-Venture

Supervision: Green Place & Acecoms, AIT Joint-Venture

Contractor: Rinson, Bhutan & Gannon, India Joint-Venture

With a span of 45.00 m, structure consists of 2 box girders with 2 webs. 0.6” strand PT was used in 40 Anchorage Type M2206 in the webs. A total quantity of 24 tons of strands were in-stalled therein. Furthermore,

the tendons were stressed to 450 tons at each tendon. The two (2) bridges consti-tutes 4 lanes, 2 lanes either way with each width at 9.8 m.

Challenges Transportation of materials such as heavy weight strands and stressing equip-ment became one of the major challenges. The gov-erning import rules and regulations of the Depart-ment of Trade under the Ministry of Trade and Indus-try, stipulates that any im-porter had to pass through the Bhutanese Revenue and Customs Liaison and Transit Office in Calcutta, India. As such, materials from Thai-land had to be shipped to the Calcutta Port and there-

after, transported over land to the Project Sites.

During the execution of the site works, it was interesting to note that also concreting was carried out by conven-tional methods, a thorough monitoring and control en-sured that quality and strength met the specifica-tion requirements of PT De-sign.

All in all, PBL Group has been privileged to step into the Land of the Thunder Dragons and is looking for-ward to facilitating the Royal Government of Bhutan in their course for infrastruc-tural development.

… the Land of the Thunder Dragon


PT Tendons consisting of 22 nos. 0.6” dia. PC Strands in each tendon

PBL’s 500-ton Stressing Jack

Contributed by Mr. Patibhan Ariyadej, who is currently the Project Director at PBL Group Ltd.

Semtokha Bridge against the mountains of Bhutan

⇐ Awaiting Stressing

“… ANY

IMPORTER HAD

TO PASS

THROUGH THE

BHUTANESE

REVENUE AND

CUSTOMS

LIAISON AND

TRANSIT OFFICE

IN INDIA.”

⇑ 3D Analysis Model of Bridge Structure

Volume 1, Issue 3

AS DESIGNER OF

THIS LANDMARK

PROJECT, PBL

HELPS THE GOVT.

OF THAILAND

EASE TRAFFIC TO

AND FRO

SUVARNABHUMI

AIRPORT

The Thailand Department of Highways had well fore-casted the dramatic increase in traffic around the vicinity of the Suvarnabhumi Inter-national Airport, which is currently seeing the influx of tourists and business clients alike, into the Land of Smiles. Since the commence-ment of construction of this magnificent infrastructure until commencement of air traffic operations, road commuters have been facili-tated by the extensive net-work of road networks lead-ing to and fro.

The improvement of the first ever Highway in Thailand, the Bangkok-Cholburi High-way, was thus planned out to cope with the estimated increasing traffic. Part of this improvement includes the construction of the Bang Pakong Interchange and the Bang Pakong bridges to cope with the volume of traffic which currently ranges f ro , 80 ,000 trips/day to over 200,000 trips/day. Statistics show that this maximum volume would further rise in the near future.

Furthermore, this Highway leads to one of the most famous tourist destinations: Pattaya in Rayong. It also facilitates traffic from the Map Ta Phut Industrial Es-tate which is also located in Rayong.

Therefore, the interchange and bridges over the Bang Pakong River, once com-

pleted by August, 2008 would be a landmark on the Maps of Thailand.

The scenic Bang Pakong River originates in the Khorat high plateau and winds through 120 km of agricultural and urban areas before discharging into the Gulf of Thailand, about 100 km from Bangkok. Although it provides freshwater sup-plies along its length, it is a tidal river, with brackish (salty) water reaching all the way upstream during the dry season, causing chronic local seasonal shortages of freshwater.

The Bang Pakong river basin is home to a government-supported industrial zone that hosts such heavy indus-tries as a tannery, a brew-ery, a distillery, and a pa-per factory (Floyd Whaley, ADB External Relations Spe-cialist).

PBL Group is proud to be a part of this land mark pro-ject by taking part in its PT girders, using multi-strand tendons. Two bridges of 11 m and 12 m width spans over a total distance of 555 m. The bridge consists of four lanes either way, i.e. a total of 4 additional vehicu-lar traffic lanes and 2 pe-destrian lanes in both direc-tions.

The total structure, valued at 18 million US Dollars, is cur-rently contracted to Vijit-phan Construction Co. Ltd.

Crossing the Rivers

The proud designers of this project is the Research and Design Unit of the Thailand’ Department of Highways. of The structure comprises of 18 – 25 m spans with 3 of 35 m spans at the middle of the bridge. Each span con-sists of I-Girders resting on crossheads located on both

land and water.

Stressing forces of 1100 kN and 1655 kN were de-signed for the top and mid-dle/bottom PT tendons for the 25 m long girders re-spectively. For the 35 m long girder, stressing forces of 1960 kN and 2687 kN were used for the top and middle/bottom PT tendons respectively.

All visitors paying courtesy calls on PBL have thus far enjoyed the privilege of visiting this site. Despite the 2-hour drive from PBL Of-fice under humid weather

Mid-span over Land

Awaiting the commencement of Stressing

Life at Bang Pakong


8/11 Soi Viphavadi 44, Viphavadi-Rangsit Road, Lardyao, Jatujak, Bangkok 10900, Thailand.

Phone: (66) 2 562 0765-9 (66) 2 941 1711-2 Fax: (66) 2 562 0764 E-mail: [email protected]

PBL Group Ltd.

T H E S T R E N G T H Y O U C A N T R U S T

business partners on this project. My special thanks also goes to the contractor and design team for their cooperation and support.

and heat of the sun, it is always a great pleasure to reach the final destination and marvel at the on-going works. On behalf of PBL Group Ltd., I would like to use this opportunity to ac-knowledge with gratitude, all the encouragement and praise we have received from both our visitors and

… crossing rivers.

PBL Chit-Chat Corner

Eng. Omar Sheikh Al Ard is currently standing by at the Aqaba Port awaiting a shipment of PT Materials from Bangkok. Therefore, If you need to meet him in person, start heading to the Port now!

PBL is currently in the process of certifying an immense Multiple-strand system. Details are ex-pected in the next publica-tion. A sneak photo taken at the location of manu-facture:

Latest inside information hint that PBL Group in Thailand shall be taking part in a new venture: Value Engineering! So, be it Post Tensioning, Shop-ping in Hong Kong, or Golfing in Indonesia, consult PBL for value-added guidance.

M 4206

The Bang Pakong River

Contributed by Mr. Patibhan Ariyadej, who is currently the Project Director at PBL Group Ltd. and overseeing PT works at the Bang Pakong Bridges

vibrant display of Jordanian culture by its Cultural Troupe.

The Ministers of both coun-tries came together to ex-change cultures and also focused on enhancing rela-tions between both countries.

As a pioneering business partner of Jordan, PBL Group Ltd. is actively pre-

The Ministry of Culture of the Kingdom of Thailand and the Ministry of Culture of the Hashemite Kingdom of Thailand was proud to embark on the first-ever, Jordanian Week in Thai-land, at the Thailand Cul-tural Center. The Week was declared open by both Min-isters and visitors were amazed by the colorful and

sented by Eng. Omar Sheikh Al Ard in Amman. Under the name of Jordan Scaffolding Company, Eng. Omar may be contacted at Shemeisani, Abdul-Hamid Sharaf Str., Amman. His contact numbers are (962) 6 5699 737 or (962) 6 5687 561 and m a i l i n g a d d r e s s : [email protected].

Jordan comes to Thailand

Sights from the Opening Ceremony

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