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TECHNICAL CENTRES

GLOBAL

EXPERTISEFOR LOCALPROJECTS

VSLnews

Elevated

segmentalroad bridges

SecondPenang Bridge

Elevated

segmentalroad bridges

SecondPenang Bridge

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INFRASTRUCTUREPROTECTION 7

SUSTAINABLECONSTRUCTION4

14BUSINESS IMPROVEMENTSustainable development at heart

16FACTS&TRENDSInfrastructure protection: Police shield

8COVER STORYTechnical Centres:

Global expertise for local projects

16SITE INSIGHTSAustralia: Revamping an icon

Vietnam: Bank HQ

Poland: Two for Torun

Ethiopia: Bridge recovery

26FOCUSElevated segmental road bridges

29R&DPolymeric ductsPT-PLUS- for enhanced durability

30TECHNICAL REPORTMitigating vibrations: Disk brakes or rubber pads?

32 TECH SHOWSecond Penang Bridge

A landmark link

Cover photo: Second Penang Bridge

NEWS, magazine published by VSL International Ltd. Kniz, Switzerland Director

of Publication: VSL Communications Jane Rousseau [email protected]

Editor in chief: Elisabeth Lichter-Rodriguez [email protected]

Co-ordinators: Christine Mueller-Sinz, Carlos Such, Doris Tong.Distribution: Anne-Marie Thevenin [email protected]

Design: Red Line Photos: Derek Allan, Herv Gouband, Philippe Guignard,

VSL staff, others Copyright:VSL 2013

BRIDGE 32

PEFC/10-31-1238

PROMOUVOIRLA GESTIONDURABLE

DE LA FORT

TECHNICAL CENTRES8

TENDONS 23

DUCTS 26

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With its highly regarded experts in the Technical Centers, VSL can tackle

even the most difficult of engineering challenges and provide what is

really best for the project. Their technical expertise coupled with practical

know-how allows them to provide advice and consultancy to both internaland external clients, optimising solutions in terms of constructability

and the costs involved, no matter how complex the project.

The centralised teams of the technical centres support decentralised

teams in 35 countries. They assist in finding alternatives when required

and come up with new solutions wherever appropriate. Their excellent

reputation, built on long-term experience, ensures invaluable support to

the local teams when addressing complex projects requiring extensive

preparation.

Such exchange of knowledge within VSLs global network enables the

groups vast pool of experience to be fully exploited and applied across a

wide variety of engineering fields.

Encouragement of lateral thought processes provides the ideal

environment in which to nurture novel - and often remarkably simple -

solutions to demanding problems.

This is how we like to serve our clients.

Optimised

solutions forcomplex projects

I S S U E T W O 2 0 1 3

Daniel Rigout,

Chairman andChief Executive Officer

VSLnews

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Sustain-abil ityis high

on the agenda for workon the Hong Kong-Zhuhai-

Macao Bridge (HZMB) projects. Alloperations have to adhere to strict

environmental policies regardingair, water and sediment quality, ecol-ogy, cultural heritage, waste man-agement, noise and the impact onfisheries.

Reducing vehicle CO2emissionsThe HZMB will provide the first directroad connection between Hong Kong,Zhuhai and Macao. The new route willhelp minimise CO2emissions fromvehicles as it will significantly shorten

journey times in the region. FromZhuhai to Kwai Chung Container Port,the distance and time will be reducedfrom todays 200km and 3.5 hours toabout 65km and 75 minutes. Similarly,the journey between Zhuhai and HongKong International Airport will be cutfrom over 200km taking approxi-mately four hours to about 40km and45 minutes.

Protecting the ChineseWhite DolphinThere are approximately 1,500Chinese White Dolphins in the east-ern part of the Pearl River Estuary

ENVIRONMENTAL PROTECTION

Sustainable construction

business improvement

4 V S L n e w s m a g a z i n e N o 2 - 2 0 1 3

VSL, in a joint venture with China Harbour and Dragages

Hong Kong, is building a 9.4km section of the Hong Kong-

Zhuhai-Macao Bridge project. Environmental protection

is at the heart of the work, which involves the design

and construction of a viaduct over the deep waters tothe west of Hong Kong.

and Hong Kong waters, with HongKongs highest density found in thewaters west of Lantau Island.

The dolphins are protected and the9.4km Hong Kong Link Road (HKLR)has been carefully aligned to avoid

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business improvement

Intrafor adopts reusable steelformwork as much as possible.However, it is still necessary to

use wood for some applications,such as to cover starter bars indiaphragm wall panels. To reduce

the environmental impact, Intraforis now using 100% FSC-compliantwood, where available, for this pur-pose. The FSC (Forest StewardshipCouncil) identifies and certifiesforests that are well managed andwhere biodiversity, productivity andthe ecology are maintained. n

The high quality of VSLs proj-ect management on QatarsLusail project led to Samsung

C&T naming it Best Subcontractorin June 2013. The new city is oneof the most ambitious projects be-ing undertaken as part of the Qatar2030 vision. VSL was awardedpost-tensioning works for the proj-ects bridges, which connect fiveartificial islands to each other andthe mainland. Two are iconic sus-

pension bridges that feature steelrings serving as 50m-tall pylonsthat represent the Q of Qatar. n

FSC COMPLIANCE

Forest-friendlyformwork

AWARD

Best subcontractor

T

he Newmarket viaduct re-placement project has wonseveral more awards. It

was successful at the Associationof Consulting Engineers NZs2013 awards, winning the GoldAward of Excellence, and theinput of design partners Beca,T&T, URS NZ and Boffa Miskellwas also recognised. Further

success came at the NewZealand Contractors Federationannual awards. To cap it all, the

Northern Gateway Alliance (NGA)- responsible for delivering theproject - won the 2013 RoadingExcellence Supreme Award andthe NZ Concrete Industry Awardin November. n

Newmarket viaduct again!

AND THE WINNER IS

VSL Thailands latest annualsafety day focused on firesafety. It was run with the

assistance of Thailands NationalFire Service Training Team, whichusually trains firefighters. Practicalexercises covered fire prevention,fire drills, oil and gas handlingand small-scale fire-fighting. Firesafety is particularly important inThailand due to the widespread useof bottled gas and the use of wood

in building houses and temporarystructures.n

SAFETY DAY 2013

Fire safety


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V S L n e w s m a g a z i n e N o 2 - 2 0 1 3 7

>VSL Infrastructure Protection has recently secured a contract toprovide blast engineering analysis and design servicesfor the glass fa-ade of the new City West Police Complex being built in Melbourne,Victoria. The blast engineering requirements for the super complex areextremely stringent. The projects fully glazed curtain wall facade hasover 20 different configurations, all of which require complex analysis toensure they meet the performance specifications to limit deformationand prevent airblast affecting the interior of the building. VSL IP is work-ing closely with faade contractor G James to engineer the optimal de-

sign solution for the main contractor. nContact: [email protected]

>Pavlovii Viaduct on Pan-European Corridor Vchas become VSLs

first contract in Bosnia & Herzegovina. The 385m-long multi-spanconcrete twin viaduct near the Croatian border has typical spans of 43m.The incremental launching method (ILM) is used to erect the single boxgirders, which are prestressed with internal tendons. VSLs client is OHL,which is building the bridge to a design by IPSA. VSLs work includesproviding the ILM technology, the post-tensioning system and permanentbearings.nContact: [email protected]

> CTT-Stronghold Canada has com-pleted its first project in Ontario. CTTscontract involved the supply and installa-tion of 500t of post-tensioning for six con-crete box girder bridges as part of theRt Hon Herb Gray Parkway (formerly the

Windsor-Essex Parkway). The Parkway isa major $1.4 billion highway infrastruc-ture project, which, once completed, willbe an essential part of Canadas premiertrade gateway.nContact: [email protected]

>In the past years, Intrafor has devel-oped to become a leading ground engi-neering specialist with emphasis onproducts and solutions with high technicalcontent. The division had outgrown the oldcorporate identity, which was imple-mented more than 20 years ago. By intro-ducing a new corporate identity Intrafor isimproving the visibility of its brand, giving a

modern, yet classic and dynamic image. n

New territory

Onward into Ontario

Corporate identity

New look and feel

> LNG projects on Curtis Island and inDarwin are the first in Australia to useVSLs AF Anchorage. VSL is involved inprestressing of 6 LNG tanks for three facilitiesbeing built on Curtis Island and4 LNG tanks in Darwin for processing ofnetwork gas. On the two projects, AFanchorages as blind dead end terminationsof the vertical tendons are used in lieu ofconventional U tubes. The new anchoragesimprove structural detailing andconstruction efficiency. n Contact: [email protected]

facts&trendsAF Anchorage on LNG tanks

Island firsts

Infrastructure protection

Police shield

First for Bosnia

Twin viaduct launch

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TECHNICAL CENTRES

Global expertisefor local projects

cover story


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VSLs Technical Centres in Europe and Asia have been

the core of the companys engineering expertise in

recent decades. VSLs capability to tackle the most

challenging projects lies in the ability of the Technical

Centres to advise, support and assist local teams and

site staff in the execution of complex work.


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We are a service provider to all ourclients, internal or external,sumsup a senior engineer. We know howto design a project and how to buildit. We can estimate how engineeringwill affect the production process.The engineers in the technicalcentre have an in-depth knowledge

of site interactions. Combinedwith their site experience, they arean invaluable consultant for thedesigner and the client.

At the same time, the centres area great training place for youngengineers starting in the group.Here, junior engineers are trainedby senior staff members, whotransfer their knowledge and bestpractices to the new arrivals. Armedwith their new expertise, the young

engineers can provide invaluablesupport to their local teams as they

SLs activities demand a highdegree of expertise and know-howin all fields of civil engineering andspecialised bridge construction.This highly skilled and specialistactivity requires staff with an in-depth knowledge of VSLs systemsand technologies. While the 50 VSLbases around the world certainlyhave the ability to handle most oftheir clients projects, they canalso rely on their colleagues from

the Technical Centres in Asia andEurope for assistance with majoror special projects and engineeringtasks going beyond their normalday to day activities.

A core team is on hand, madeup of structural and mechanical

engineers, method engineers andexperts in particularly specialisedactivities, such as stay cables, VSoLor construction equipment. Ondemand, they assist the local teamsand their clients in finding the bestsolution, looking at alternatives andseeking opportunities to identifywhat is best for a project and tohelp move it in the right direction.The client can be confident that theexpertise of the Technical Centresis available, if need be, at every

phase of the project, right from thestart.

cover storyTECHNICAL CENTRES

V

A specialised team of engineers for specialist constructionTechnical Centres engineers (TC engineers) define construction, specify the equipment and theinstallation on site and carefully check interfaces with permanent work. They also develop the schedulefor the construction of projects, establishing the materials and human resources required, carry out the

design of specific equipment (such as formwork or safety equipment) and supervise their fabrication. TCengineers are there at the start of construction to finalise the methods that will be used on site.

TC engineers take also an active part in the design and optimisation of structures to allow use of VSLsystems and construction methods and propose alternatives to simplify construction and make best use

of materials.

Engineers from the Technical Centre in Singapore are not only responsible for all the equipment used on

special projects designed by the Technical Centres, but is also developing equipment for the installationof post-tensioned cables. The team has designed a new generation of multistrand stressing jacks and is

presently carrying out further development of a range of tailor-made equipment needed for the installationand stressing of prestressing cables for use in nuclear power plants in Korea, France and Russia.

We do notoutsource -we do it allourselves.

Of course, a

team of brightthinkers createsa pool of energy.

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Contributing to smooth project executionAssistance from VSLs Technical Centre in Switzerland

is contributing to the successful construction of athree-span cable-stayed bridge in the USA. Early inputinto the construction methods helped save money and

time as well as making the work safer. The Ironton-

Russell Bridge is owned by the Ohio Department of

Transportation (ODOT) and links the city of Russell,Kentucky with Ironton, Ohio. The US$81.3 millionproject, which started in March 2012, is due to be

completed by 2017.The side spans are being built on specially designed

falsework simultaneously with construction of the pylonto create land access for the installation of a form-traveller and erection of the 275m main span. VSL is

supplying the 130t form-traveller. In joint venture withits US partner VStructural, VSL is also providing 125t of

post-tensioning in addition to the supply and installationof 305t of the VSL Stay Cables. The bridges main spanconsists of 30 segments each supported by two stay

cables ranging from 14 to 33 strands. Each segmentweighs about 180t with a length of 8.9m and a width of

13.8m. The scope of work carried out by the Technical

Centre in Europe (TCE) includes:Design of the form-traveller, issuing engineering

drawings and a fully detailed 3D model built usingSolidWorks, checking of the shop drawings issuedby the steel fabricator, production of an operationalmanual including construction methods and assembly

kinematics, supervision during fabrication, load testingand trial assembly of the form-traveller.The underslung form-traveller was manufactured in

April 2012. It was delivered to site in May 2013. Buildingthe bridge requires the installation and partial stressing

of the stays before casting the concrete to preventexcessive bending in the deck. After concreting, a

second re-stressing operation is performed on the stayin order to absorb the decks deflection before launchingthe form-traveller to the next segment.

VSL proposed the innovative use of precast stay anchorblocks, in order to eliminate the complex stay detailsrequired to transfer the stay force from the form-

traveller to the structure, and to reduce the construction cycle time. Precasting the stay anchorage blocks with this variable geometry and place them directly inthe form-traveller, omits need for temporary fixity of the stay anchorages to the traveller, which is technically complex. The two hydraulic systems developed for

use on the project enable independent control of the form travellers structural frame and its formwork. This contributes to a significant weight reduction in thetelescopic parts. This project is challenging due to strong interaction between equipment design and stay cable construction engineering, which has required closecollaboration between the bridge designer and the VSL design team. Erection of the form-traveller on the bridge is due by the end of 2014.

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tackle challenging projects.It is interesting to work on severalprojects at a time - this is veryrewarding,comments an engineer.Every project has an aspect

that gives you satisfaction, We

For the form traveller of the Gateway upgrade project, TCA suggested that the frames were

splayed on plan. The rear reaction to the deck remains directly over the webs.

The form-traveller design provided excellent access to all the required working areas and

allowed placing of prefabricated web reinforcement.

Innovative form-travellerdesignVSLs Technical Centre Asia developed an

innovative form-traveller design that madean important contribution to the successful

completion of the Gateway Upgrade Project

in Brisbane, Australia. The design allowedprefabricated web reinforcement to be lowered

into place, saving time while ensuring that theoperation could be carried out safely. VSLs

Technical Centre Asia was involved in theproject from an early stage, helping to definethe construction methods and influencing the

design of the bridges permanent works byproviding advice on constructability issues.The New Gateway Bridge has an overall

length of 1,627m including a 260m main span,which is one of the worlds longest concrete

bridge spans unsupported by stay cables.The main span deck consists of a twin-cellbox-girder, cast in-situ using the VSL form-

traveller to produce segment lengths of3m, 4m and 5m. The heaviest segment cast

using the form-traveller was 386t. The depthof the 29.35m-wide deck at the main-spanpiers is almost 16m. In order to place web

reinforcement steel quickly and safely, itneeded to be prefabricated and lowered into

the web formwork.However, traditional form-traveller designshave the main frames parallel with the bridge

so that the loads are applied to the webs ofthe deck. This does not allow lowering of

prefabricated web reinforcement cages intothe formwork. TCA therefore suggested aninnovative approach that allowed the frames

for the form-traveller to be splayed in plan.The rear reaction to the deck remained directly

over the webs and, close to the leading edge,a transverse beam supported the frames

communicate with the designers,because we can advise on howto design a construction-friendlybridge. We offer the best solution.Consultants do appreciate.

The solutions that are devised are

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Cost-effective solution for a suspension bridgeAnother technical milestone for VSL was the design and construction of the Subansiri Suspension Bridge, where the

adoption of innovative solutions enabled the costs

and complexity of construction to be greatly reduced.

The suspension bridge over the Subansiri River has

been built to support a conveyor belt used to carry

aggregates for construction of a dam. VSLs scope

of works was, apart from the design of the bridge,

to supply the bridges main and hanger cables as

well as to erect the main cables and the deck. This

specialist work was carried out in collaboration

with the Technical Centre Asia, which undertook the

design and detailing together with the construction

engineering for the whole bridge. In addition, a TCA

engineer and superintendent were seconded to the

project.

Construction of river piers was cons idered by the main

contractor to be impractical and unsafe as the flow

in the Subansiri River triples during the rainy season.

This meant that the bridge had to span 300m. TCA

proposed a suspension bridge that was structurally

similar to the Mamberamo Bridge, which VSL

Indonesia had previously worked on. Such suspension

bridges have two pairs of main cables. The hanger

cables that support the deck are only suspended fr om

one pair of main cables, switching between the two pairs at the centre of the main span. This means that each main cable runs

straight over half of the main span length, improving aerodynamic stability. Technical Centre Asia produced all shop drawings

and was responsible for development of the methods for assembling and installing the main cables and erecting the deck.

The solutions developed by VSLs Technical Centre demonstrated how the costs of building a suspension bridge can be

minimised by using parallel galvanized strand bundles as main cables. In addition, the method of erecting the main cables

avoided the need to install a cable way. The approach exploited also the fact that the river is navigable, allowing the bridge

deck to be preassembled into modules on land, delivered by barge to site and lifted along the hanger cables into position.

Main cables that are 515m long and made up of 30 strands pass over saddles on top of steel pylons reaching 35.9m high above

deck level. The hanger cables are su spended at 9m intervals from the pairs of main c ables. To avoid using a temporary pontoon

bridge which could be flooded, the VSL solution was to establish a straight assembly bed along the river bank and a launching

track on the island side, and to use fixed rollers to support the main cables. The main cable was pulled over the roller supports

by a winch until the front end reached the pylon.

For crossing the river, a pair of temporary suspension cables was installed next to the pylon leg. The main cable was suspended

from the temporary cable by special hangers and then pulled over the river. Saddles were installed at ground level and the ca ble

was lifted simultaneously on both pylons using strand lifting units. After all four main cables had been installed, the 16m- to

20m-long deck modules were transported on barges to the lifting points. Four SLUs used the hanger cables to lift each module

to the desired level. The final operation was to install the conveyer belt itself.

Visualize ideas before the computers are switched on.

and transferred the reactions across to thewebs. This allowed sufficient space for the

prefabricated web reinforcement cages to belowered directly into the formwork. The design

provided excellent access to all the workingareas and could accommodate the full depthvariation of the deck from 15.7m to 5.2m along

the cantilevers. As a result, the site teammanaged to achieve a segment construction

cycle time of three days. This contributed to a

significant reduction in the construction timeof the main spans.

The basis of the design was the standardmodular form-traveller used extensively

throughout the world but with significantmodifications for the project. Designersfrom the VSLs Technical Centre Asia spent

time with the site teams to ensure that thedesign catered not only for physical project-

specific constraints but also addressed otherfactors, such as the high labour costs andextremely high safety expectations commonly

encountered in Australia.

Understanding of the fabrication processesand awareness of the progress allowedVSLs Technical Centre Asia to optimisedesign changes to minimise disruption to

the schedule. VSLs designers also assistedwith the assembly and commissioning of thetravellers on site. During construction, they

then provided support to ensure the smooth-running of the equipment and to design

any enhancements or additional featuresrequested by the site teams. Technical CentreAsias involvement continued to the end of

the construction, in designing the adaptation

of the traveller frames for use as deck-stitching beams and in developing the heavy-lifting methods used for the lowering of theformwork.

very often technically one of a kind,not merely re-using what alreadyexists but developing and innovatingto design what is best for a project.The teams give support from the

beginning to the end of a project, and

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Being constantly on a learningpath means nothing is stagnant; allproblems are overcome at the end.

Tackling unusual design requirements: Distrito 38 SpainAn alternative design from VSL has helped improve the layout of acomplex office building at the heart of a new business zone in Barcelona:

Distrito 38. Switching from structural steel to post-tensioned concretehas allowed the creation of large cantilevered slabs and open column-

free spaces. It was important in this project to develop structures with aflexible layout that allows for later rearrangement as new and developingrequirements emerge.

The site faces part of the Paseo de Zona Franca, a key thoroughfare in thedistrict. Using this as an anchor, a 7.5 x 7.5m grid has been defined as the

basis for the layout of six planned buildings and their parking areas. ArataIsozakis D38 offices development is probably one of the most challengingbuildings built in Barcelona in the last years. The building has a distinctive

appearance, with open missing sections on each level and cantileveredfloors above. The sides measure 52.5m x 52.5m and the building hasa height of 46.5m. The overall shape is almost a cube with a central

concrete core and the offices arranged like a square doughnut around it.A peculiarity of the building is that all the floor slabs are different: only

one or two cover the full area, the others have cut-outs to make themC-shaped or L-shaped. This allows the interior of each to be organisedinto one, two or three units. Further complications come as the C and

L-shapes on different floors rotate around the core. Originally, the floorswere arranged with a matrix of columns spaced on a 7.5m by 15m grid.

As a result, the original, conforming solution was planned as a steelstructure with extensive use of tension members to hang parts of theslab from the floor above. Some columns stood on a beam, there was

no continuity in the columns and it would have been very complicated tobuild the building. In essence, VSLs proposal was to change from steel to

concrete and then to make every single slab independent from the othersby means of post-tensioning. VSL also removed all internal columns andsome of the external so that the doughnut was left completely free for

office space. The design created huge cantilevers and more than 50%of all the buildings columns were removed. The building includes slabs with clear spans of 15m by 30 and 45m, with cantilevers of 7.5 and 15m, solved with a

combination of waffled and ribbed post-tensioned slabs together with post-tensioned edge beams. It was clear that the solution was ideal and so VSL proposed itto the main contractor, which put it forward to the architect and consultant. VSL was asked to produce the final solution and the Architect was so happy with theproposal that one of the associated architects was brought over from Japan to fine tune the final column layout with VSL. All parties were very pleased with the

result as it improved the buildings layout and saved both money and time.

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becomes a communication andinformation point for the designer,while supporting the client. Duringproject execution, the teams onsite will receive all the necessarysupport for installing and operatingthe systems, closely followed byspecialist input from the TechnicalCentre to ensure quality control.

The teams from the TechnicalCentres in Singapore, Thailand,India, Switzerland and Spain enabletheir local colleagues to get on

with the job without getting lostin the details. They train, listen toand learn from others. I found mydream job without knowing thatit existed, says a member of theSingapore team. You arrive andbring your former work experiencewith you and use it to make thingshappen within a dynamic team ofexperts.Every new project bringsnew challenges to tackle, so too doVSLs newer business lines such aswind turbine erection and offshore

applications. Striving to be a genuineservice provider is the key.n

log the feedback from one projectto the next. The Technical Centresthus become a design hub for theVSL network, producing documents drawings as well as fabricationand operational manuals thatwill become the standard for futureprojects.

Constructableand efficientTeams from the Technical Centresare involved from the very beginning,starting with a technical SWOTanalysis, through to providing thetender teams with drawings andimages for a better understandingof the project and helping producethe associated bills of quantities.We propose alternatives, newsolutions, is how a stay-cable

specialist puts it. We want to doa technically sound job, but alsoto contribute to the aesthetics ofthese landmark projects. A cable-stayed bridge has to integrate wellinto the landscape. Its design andarchitecture are important for theprojects success.

Stay-cable projects are a goodexample as evolutions anddevelopments in recent yearshave contributed to improvements

not only in the life and structuralbehaviour of bridges but also theiraesthetics. The VSL Saddle, theSSI 2000 Compact System andvarious damping solutions are justa few of the key developments.Every project is considered unique,demanding bespoke solutions butwithout taking careless risks. Ourclients requirements challengeour capacity to innovate, to findnew solutions, observes anengineer. Once a project has been

secured, the Technical Centre

This is the realdriving force -there are alwaysnew challenges.

You can never sayyouve seen it all.

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Australia

Revamping an icon

> Rehabilitation of the iconic

Tarban Creek Bridge is beingcarried out by VSL under a contractawarded by Roads & MaritimeServices of New South Wales (RMS).Giving the 38-year-old archstructure a new lease of life involvesprovision of two new supports of the

>The low deck of the old Hua ZongBridge caused problems at timesof flooding and so a new designedstructure was raised by 3m. The147m-long bridge on the Jiang JunRiver is on a major route in TainansXue Jia district but use of a halfand half construction method haskept traffic flowing. VSL is supplyingand installing its SSI 2000 Stay

cable system for the hangers of the16m-wide, three-arch steel structure.nContact: [email protected]

bridge deck by construction of two

portal structures, which are 18mhigh and 35m long, and replacementof the bridges concrete diaphragmswith steel cross girders. A keyfeature will be the construction ofthe portals massive post-tensionedbeams. VSLs Technical Centre

Taiwan

Higher deck

designed a temporary steel

falsework platform that will bepreassembled on ground togetherwith reinforcement and formworkand slid and lifted into castingposition by using sliding and heavylifting techniques. nContact: [email protected]

site insights

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Vietnam

Elevated segments

>Kelok 9 is a unique name of anelevated road consisting of nineturns and stretching over 2.5 kmin length. Officially opened on31st October 2013, the road whichwas financed by the centralgovernment was built to solve thebottle neck of highway betweenBukittinggi in West SumatraProvince and Pekanbaru in RiauProvince. The width and gradient ofroad was significantly improved inorder to minimise traffic congestion.

VSLs scope of works included post-tensioning and engineering of asection which is composed of a castin situ balanced cantilever bridge.nContact: [email protected]

>Precast segment work will becarried out by VSLas a specialistsubcontractor JV team on an ele-vated section of the Ho Chi MinhCitys new Metro Line 1. Most of the19.7km route is elevated, runningon viaduct for 17.3km as it passesthrough 11 of the lines 14 stations.VSL is working on the Ben Thanh

Market to Suoi Tien Park section.The citys Management Authorityfor Urban Railways is developingLine 1 as a new spine for the publictransport system. It is expected tocarry more than 160,000 passen-gers daily in its first year, increas-ing to 635,000 by 2030. nContact:[email protected]

> The Central Garden Buildingproject is a residential scheme

located in the Qian-Jin District ofKaohsiung City, Taiwan. The buildinghas a height of 37 storeys and aseven-storey basement. A total of 36sets of VSL dampers will be installedfrom the 11thfloor up to the 19th. Thewall-type dampers are 1.35m highand use one viscoelastic damperunit per set. They are integrated intoprefabricated steel panels that areinstalled directly in the structureduring construction. Installation ofthe VSL damper systems started in

June 2013 and will be completed in2015. n Contact: [email protected]

>VSL Vietnam will complete itspost-tensioning work at the newcity headquarters of Vietcombank inHo Chi Minh City in December 2013.The Vietcombank Tower project hasinvolved the supply and installationof 200t of strand for post-tensionedslabs and beams in the 35-storeyoffice building. The tower also hasa four-level basement and areasfor services, retail, restaurants andparking. Vietcombank is one of the

countrys largest local commercialbanks and the new buildings3,200m2site is right in the centre ofthe downtown area. nContact: [email protected]

Taiwan

Controlling structural behavior

Indonesia

Nine turns Vietnam

Bank HQ

CourtesyofPublicworksDepartmentofRepublicofIndonesia

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>Two pairs of VSL form-travellershave recently begun constructionof a bridge on National Freeway No8. The structure has a double-boxbridge deck with spans ranging inlength from 65.57m to 110m and

girder depths of between 2.8m and5.65m. The bridge superstructureis being built by the cast-in-situsegmental balanced cantilevermethod, so the symmetricalsegments of the 20m-wide deckare constructed on both sides ofthe piers. The VSL form-travellersare of a modular design thatenables the truss and the widthof the bottom slab to be adjustedto suit the bridge cross-section. nContact: [email protected]

> Typhoon Morakot destroyedthe old Shan Mei Bridge in theTanaiku National Park and so thereplacement structure has beendesigned to ensure integrity evenwhen torrents come rushing down

Taiwan

Designed for typhoonsfrom the mountains. The newdesign has a 115m-long single steelarch fitted with the VSL SSI 2000stay cable system for the hangersfeaturing the latest developmentsin anchorage technology and

Taiwan

Freeway travellers

corrosion protection systems.VSL is supplying and installing20 sets of 6-31 anchorages, 1,000mof galvanised strand and 350m ofHDPE pipes. n Contact: [email protected]

site insights

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> In order to replace a levelcrossing with an overpass, VSLwas recently awarded the designand supply of 3,925m2 of VSoLRetained Earth Walls. The VSoLwalls will stand up to 11.7m highand be faced with 2m by 2m plaingrey panels. The retained earthwalls are an integral part of theRobinson Road project, which is

designed to remove a bottleneckand deliver a safer and moreefficient transport network by theconstruction of a road overpasscrossing the rail line. n Contact:[email protected]

Australia

Safercrossing

Australia

Terminal slab

> Leighton awarded Intrafor acontract for a MTR interchangestation,part of the new 17 km longSha Tin to Central Link metro lineproject. Located under the podiumstructure of the existing Hung Homstation, the works comprise 1075lmof 1.2m thick diaphragm wall andbarrettes ranging from 20m to

60m in depth, representing a totalof 40,000m3 of excavation. 5 slurrywalls totaling another 3,400m3 of

excavation are also part of Intraforsscope. The main challenge is to workunder a very low headroom of 5.5m.Excavation is carried out using mini-cutters and special low-headroomgrabs with boom and grab lengthreduced to the minimum. Cranes hadto be modified and a special gantrysystem had to be developed to move

equipment and reinforcement cages.n

Contact: guillaume lamoitier@vsl-

intrafor.com

Hong Kong

Very low headroom

>VSL has been awarded a contractto design, supply and install post-tensioning and associated slab re-inforcement at the Patrick Terminalin Port Botany. The 45,000m2 ofpost-tensioned pavement is part ofa container terminal expansion pro-gramme for a major logistics com-pany. Use of a post-tensioned slab

was adopted by the client as it offeredexcellent abrasion resistance againstthe braking and turning stresses im-posed by the terminals automatedstraddle cranes. The dramatic re-duction of joints improves slab ro-bustness and also minimises therisk of pavement rutting. nContact:[email protected]

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> VSL has recently completedmissions on two bridgesin the cityof Torun in northern Poland. Thehighly curved Zolkiewski EstakadaViaduct, which opened in August, is

supported by stay cables installedby VSL Polska.

Work took place simultaneously ata nearby 265m-long arch bridgeover the Vistula River with twospans, where VSL carried out athree-month operation to lift 16 deck

segments. In the first phase, thesegments weighing up to 250t -

were lifted 15m from a pontoonand suspended from temporaryhangers. They were aligned in asecond operation before the loadswere transferred to permanent

hangers. nContact: [email protected]

Poland

Two for Torun

> Construction of the Troya

Bridge is nearing completion.VSL supplied both longitudinal andtransverse electrically isolatedtendons (EIT) for cast-in-placebeams and slabs. Tendons rangedfrom the four-strand bondedslab system to the multistrandCS Super 6-37. The bridge, whichhas a 200.4m-long steel archmain span, crosses the VltavaRiver. Metrostav divisions 2 and 5are building the bridge on behalfof the City of Prague to a design

by Mott MacDonald Praha withconstruction analysis by Novk &Partner.nContact: [email protected]

Czech Republic

EIT forTroya Bridge

site insights

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> A well adapted solution hasenabled VSL to secure the contract tosupply the stay cable system for theNovosibirsk Arch Bridge in Russia.VSLs remarkable concept allowsthe bridges 156 stays to be lifted

without using any type of platformat arch level. The concept includesprefabrication and lifting of

complete stays, which reduces thetime needed for erection from threemonths to two. VSL is also providingequipment and supervises the stayinstallation by contractor Sibmost.The bridges designer, Stroyproject,

has already worked with VSL on anumber of Russian projects. nContact: [email protected]

Turkmenistan

Beams atAshgabat

Qatar

Work inprogress

Russia

Repeat

success

> Following on from the heavylifting works, VSL has now beenappointed for the design, supplyand supervision of post-tensioningfor the beams at the AshgabatsCongress Centre in Turkmenistan.Bouygues Turkmen is building thecentre, which features beams thatspan between 40m and 45m andincorporate VSLs GC6-12 and GC6-19 anchorages. VSL is due to supplythe post-tensioning materials

and equipment by the end of 2013and will then supervise the post-tensioning activities in early 2014.nContact: [email protected]

> After successfully completingthe original cut-off wall scopeof 52,500m2 over a plan length of3,150m on the New Port Project inQatar, VSL-Intrafor were awardedadditional works comprising theconstruction of an additional55,530m2 of cut-off wall over a

plan length of 3,210m, includinggeotechnical investigation worksand providing specialist plasticconcrete. The cut-off wall is beingconstructed using VSL-IntraforsBC40 Cutter equipment and aspecial plastic concrete mix;excavation works for the wall arebeing carried out to depths of up to22m below existing ground level. Thecut-off wall reduces the horizontalflow of water through the subsoiland fractured limestone, facilitating

the safe and economical dewateringand dry bulk excavation works in theports access channel. n Contact:[email protected]

Toughened tunnel.The latestscheme in the development ofDubai International Airport isthe strengthening of the 1.5kmBeirut tunnel running under theairport. VSL won the contract toinstall 280t of post-tensioningto improve the load-carryingcapacity of specific areas of thetunnel roof. The strengthenedroof will allow the area aboveto be used as aircraft stands forfuture airshows.

Jumana Island access.A newman-made island is currentlybeing developed in the heart ofDubais beachfront shoreline ofJumeirah. VSL is providing its6-19 and 6-12 post-tensioningfor use on the 502m-long nine-span bridge that will connectJumana Island to the Jumeirahcoastline. The bridge is set to becompleted in February 2014.

Stays, pipes and dampers.Aconsortium led by Viadukt hascontracted VSL to supply andinstall the stays for the DravaBridge in Croatia. The bridge,designed by the CroatianInstitution of Civil Engineers(IGH), is a suspended compositesteel bridge with a 420m mainspan over the river, flanked bysemi-prefabricated concretestructures. VSLs work includesthe engineering and supplyof the stay-cable systems470t of strand, 80 sets ofanchorages, HDPE pipes and

friction dampers. VSL will alsobe providing equipment andsupervising the installation.

Bridge upgrade. VSL issupplying and installing strand,anchorages and bars for thestrengthening of the Wan DaBridge in Taiwan. The 735m-longcrossing of the Kaoping Riverstands on 22 piers and requiresthe installation of 450t of15.2mm-diameter strand,16,800m of galvanised steel

ducts, more than 500 sets ofE6-22F and E6-27F anchoragesand 1,250 PT bars.

N O T E P A D

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>A new underpass is being builtin Rickenbachto allow pedestriansand cyclists to cross under therailway. VSL slid the 280t concretebox, fabricated on site, into its finalposition underneath a temporaryrailway bridge while the line wasstill in operation. The box was pulledmore than 20m at a maximum speedof 10m/hour on a slide system,

closely guided to ensure a smoothoperation. n Contact: [email protected]

> Stringent requirements had tobe met in work for two rail bridgepackages in Camorino as part ofthe Alptransit Gotthard project.VSL won the contract to supplyand install prestressing tendons,

which are electrically isolated forprotection against stray currentsand corrosion. Limited space within

the bridge cross-sections meantthat special deflection elementshad to be constructed. Meeting theclients deadlines while achievingthe stringent quality requirementsdemonstrated the efficiency of the

VSL system and the expertise of thesite personnel. nContact: [email protected]

Switzerland

Sliding box

Switzerland

Alpine achievement

site insights

> The first section of the steelroof structurefor the latest Airbushangar in Toulouse, France wasraised by VSL in June. The roof con-

sists of two parts, weighing 970tand 770t. A single operation raisedthe first section by 24m using10 lifting points. VSL had already

performed the roof lifts for the twoprevious Airbus hangars in Toulouse.nContact: [email protected]

France

Repeat hangar

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> The latest generation ofprestressing tendonsis being used

for two bridges on ZrichsDurchmesserline rail extension.Letzigraben Bridge, which has atotal length of 1,160m, has beenunder construction since 2009 anderection of the 400m-longKohlendreieck Bridge began in2012. VSL is subcontractor for theprestressing work on both bridges.Post-tensioning is being doneentirely with the latest electricallyisolated tendons to ensuremaximum corrosion protection.

More than 17,000m of tendons willbe installed, mainly type VSL 6-31.nContact: [email protected]

Switzerland

High-techtendons

>Extension of Switzerlands A16highway in Court in the north-western part of the country includesconstruction of several tunnels andbridges. More than 4,000 temporaryand permanent soil anchors will beinstalled to secure tunnel entrances

and other retaining structures. VSL,

working as subcontractor with MartiSpezialtiefbau, is supplying andinstalling the anchors. The largequantity represents a substantialbut positive challenge for VSLslocal production and logisticsfacilities. n Contact: [email protected]

Switzerland

Secured with anchors

>Teams from VSL have recentlycompleted workfor the supply andinstallation of post-tensioned6-31 cables as well as elastomericsliding bearings for the upgrade ofa Swiss hospital. Post-tensionedcantilever beams were necessaryto take the load of the eight newstoreys being added toaccommodate 350 employees. Inaddition, bearings were fitted toisolate some slabs and ensure the

stability of the structure in the eventof an earthquake. n Contact:[email protected]

Switzerland

Hospitalupgrade

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> VSL has carried out a fullstructural assessment of St PaulsCathedral in Abidjan. The 3,500m2

main area of the cathedral iscovered with a roof that is supportedby a tensioned cable systemattached to a 70m-tall concretepylon. The nature of the structure

made access difficult and so theVSL technicians used rope accesstechniques to inspect the pylon,

stay cables and the top of the roof.The structure was surveyed usingLaser Scan technology to create a3D model. Other techniques usedincluded Ferroscanto determine

rebar positions and chemicaltests to assess carbonation. Thestay cables were also inspected,

including endoscopic surveysto determine their condition. nContact: [email protected]

> In the very remote southernregion of Ethiopiaa new 128m-longsteel bridge crossing the Omo Riverwas built in 2011. Due to constructiondefaults the bridge collapsedinto the river. VSL was chosen tocarry out the recovery of the 550tbridge, including the method to beimplemented. The bridge was liftedfrom the water, put on temporary

supports and launched 36m intoposition following repairs.nContact:[email protected]

Ivory Coast

Cathedral challenge

Ethiopia

Bridge

recovery

site insights

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> The city of Puebla hascelebrated the recent openingof a new landmark, the CaptainCarlos Camacho Espiritu Viaduct.This cable-stayed bridge is morethan 500m long and has two pylons,standing 50m high. VSLs scopeof work included the supply andinstallation of the SSI 2000 Staysystem and the tensioning of high-

strength bars in a project that tookjust 28 days. The bridge was builtby the Puebla state government aspart of scheme to transform theregions roads for the benefit of themore than 1.5 million inhabitants.Design was by International BridgeTechnologies (IBT) and VSLsclient was GH Anderl Consulting &Construction. n Contact: [email protected]

Mexico

Citylandmark

>The Aracar Viaduct is part ofthe Rodoanel Mario Covas projectin So Paulo. It consists of twodecks, each with 52 spans of 30m.The spans will be post-tensionedlongitudinally with eight cablesof nine strands. The challenge onthis project is to complete 120m of

bridge deck per week. [email protected]

>A 12-month project is nearingcompletion in Panama City. TheCinta Costera III project required560 post-tensioned beams, each40m long and weighing 90t. Thebeams contain a total 2,156t ofpost-tensioned strand. VSL wasresponsible for the supply of mate-

Panama

PT

completion

> Three world records will be

broken by a 1,620m-long compositebridge being built for a new high-speed railway in North West of Spain.VSL was awarded several contractsto install a total of 25,000t of thesteel structure. The first part of the

work was finished in August with the

installation of the pier tables on top ofthe four main concrete piers. At eachpier, two 400t segments had to bepositioned in a complex lifting, tiltingand lowering operations. nContact:

[email protected]

Spain

Recordbreaker

Brazil

120m per week

rials, as well as the installation,stressing and injection. nContact:[email protected]

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Indias economic surge has resulted in a massive increase in

the number of private vehicles on its roads, overwhelming

the transport infrastructure. Use of VSLs precast segmental

construction technique to build elevated roads and highways is an

efficient option, fast and safe.

ELEVATED SEGMENTAL ROAD BRIDGES

Decongesting Indias roads

focus

he 3.3 million kilometres overalllength of the Indian road networkmakes it the second largest in theworld. About 65% of Indias freightand 80% of its passenger traffic iscarried by road. National Highwaysconstitute just 1.7% of the networkbut carry about 40% of the totaltraffic. The number of vehicles has

been growing at an average pace of10.16% per annum over the last fiveyears while the road network hasgrown by only 4% annually1.Elevated road and metro construc-tion projects have been initiated toalleviate the heavy traffic in citiessuch as Mumbai and Bangalore;VSL has been working on some ofthese challenging schemes.

Above trafficAvoiding continuous disruption to

the traffic underneath is a decisiveelement in favour of using the pre-cast segmental constructionmethod for both elevated highwaysand metro viaducts. Precast seg-mental construction is extremelywell suited to large urban bridgeprojects, allowing the safe and fastconstruction of high-quality anddurable elevated bridges even inconfined areas with limited access.

T

Bangalore the IT capital of India - is growing into a major metropolis. The government decidedto build an elevated highway to improve the infrastructure and provide direct connectivity fromthe city to the IT offices, in Electronic City, 10km from the busy Silk Board Junction on Hosurroad. The 8.05km-long Bangalore-Hosur Elevated Expresswaywas built using the precastsegmental technique with the span-by-span construction method. The segments were erectedusing self-launching overhead gantries, supported on the expressways piers. Three gantrieswere in simultaneous operation for the span-by-span erection. VSLs scope of work includedthe design, fabrication, supply, erection and operation of the three gantries used for spanerection, the complete deck erection as well as the provision of geometry control software forthe segment production in the casting yard. In addition, VSL provided construction engineeringservices, produced the shop drawings for segment casting, carried out deck post-tensioningand installed the permanent bearings. The need to build the elevated expressway in the middleof a busy highway with traffic on both sides led VSL to propose heavy-lifting techniques as analternative to the erection of the gantry by cranes. Assembling and commissioning the maingantry trusses at ground level substantially reduced the risks of working at height, and greatlyreduced the usage of cranes and other lifting equipment. As such, the method is considerablysafer than conventional means for this type of work. Precast segmental construction on such alarge project demonstrated that it is one of the most appropriate solutions for major cities witha high traffic density.

One of Bangalores longest flyovers

1Source : National Highways Authority of India,

www.nhai.org

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Minimisingtemporary worksDifficult traffic arrangements com-bined with a lack of space at groundlevel and sometimes poor soil con-ditions make the elevated highwaysolution a logical choice. Span-by-span precast segmental erectionwith a launching gantry is a con-struction method that minimises

the temporary works required dur-ing construction while optimisingthe permanent works design. VSL

has an extensive expertise and alarge team of experienced andqualified personnel available tomanage, supervise and operate itserection equipment.

Optimising costsPost-tensioned precast segmentalconcrete bridge construction isan advanced construction method

that provides many advantagesto the projects management.Construction quality is improved

Mumbai Metro One Private Limitedis implementing a state-of-the-art mass rapid transportsystem for the city of Mumbai. This line crosses the elevated Western Express Highway, whereit requires an 83m span for which consultant Systra MVA designed a cable-stayed bridge. Itslocation near the future WEH Station is on a very congested site in a highly populated area withheavy traffic, dense crowds, underground utilities and a pylon height limit due to the proximityto the airport. VSL built the superstructure for the crossing, which is designed with a cast-in-situ U-shaped deck built in balanced cantilever with stay cables supported from two pairs of

pylons. The VSL SSI 2000 Stay cable system was used together with the third generation ofVSLs patented saddle.VSL designed a special jig to achieve the highest levels of positioning accuracy when seatingthe saddles. The balanced cantilever cast-in-situ concrete bridge deck was built using twopairs of form-travellers. Heavy traffic moving day and night on the highway below created achallenge in the form-traveller design. It was essential to ensure that crews could work safely24 hours a day whilst allowing the traffic below to continue to flow without risk. The form-travellers featured well positioned work platforms to allow the safe execution of all taskstaking place on the structure, including post-tensioning works and stay-cable installation.VSLs teams clocked over 240,000 man-hours safely with zero lost-time incidents.

An innovative cable-stayed bridgein the heart of Mumbai

VSL has built a 4.2km elevated highwayin Bangalore for Navayuga BengalooruTollwayPrivate Limited. Building the

precast segmental viaduct involved erectionof 1,421 segments over 120 spans usingthe VSL overhead launching gantry andincluded the installation of 1,625t of post-tensioning. Built along the central medianof the existing National Highway, theviaduct passes through densely populatedresidential and commercial areas wheretraffic is heavy. About two thirds of thespans have horizontal curvature includingseveral S-curves with a minimum radius of360m combined with a 7% cross-fall and3% gradient. The complex construction

of the viaduct created great challenges.

Minimising the construction period wascritical as it was a build, operate andtransfer project. VSL had committed to a2.5-day per span erection cycle but achievedeven faster installation, with an averagecycle time of less than two days a span.The record was a 36-hour cycle time andpeak production of 18 spans in one month.VSL demonstrated speed, accuracy, qualityand safety on the project and continuouslyengaged with the main contractor onall issues, ranging from the casting ofsegments using VSLs geometry control

software to erection, surveying and finalspan alignment.

Complex constructionfor a tollway

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focusELEVATED SEGMENTAL ROAD BRIDGES

due to factory conditions in whichthe precast segments are built.Production is more cost-efficientand fast erection rates can beachieved when post-tensioning isexternal. The method allows bettercontrol of construction costs asquantities are optimised, limitedequipment is needed and there isless environmental disturbance asonly localised working areas and asmall footprint are required atground level. In addition, the mate-rials are easy to recycle at the end

of their life. All these factorscontribute to reducing the overall

project risk for the contractor, thedesigner and the owner.

VSL has extensive experience in theconstruction engineering and ge-ometry control of precast segmen-tal bridges. The constructionmethod is fast and versatile, allowshighly controlled quality, and avoidsdisruptions at ground level. Allthese aspects have made it the pre-ferred solution for many long, ele-vated highways and metro projects,as they allow securing the schedule

and the cost, thus mitigating con-struction risks. n

An upgraded access was needed toconnect Bangalores international

airport with National Highway 7 and sothe National Highways Authority ofIndia launched a project to build a22km-long expressway.The DevahalliHebbel expresswayhas a six-laneelevated viaduct that is 4.5km long,with 7m-wide service roads and twoflyovers, each of 500m. Traffic flowbetween the airport and Bangalore Cityremained uninterrupted. The projectwas built under the National HighwaysDevelopment Programme on a design,build, operate, finance and transfer

scheme through a public-privatepartnership. VSLs scope of workscovered the design, fabrication andsupply of 12 cells for precasting pierfield segments. The project includeddesign, fabrication, supply andoperation of a new erection gantry usedto build the two flyovers. VSL alsoadapted and operated one of its existinggantries for the erection of 3.7km ofviaduct. In addition, VSL providedgeometry control for all three bridgesas well as carrying out external post-

tensioning, installation and grouting ofbearings.

Upgraded accessto airport

Chennai, formerly known as Madras, has an estimated population of 12 million, making it Indiasfourth-largest metropolitan city. To provide additional public transport, Chennai Corporationdecided to develop a metro rail project, connecting the central bus station to the airport.VSLs scope of work on the 6km-long elevated viaduct covered the design, engineering andsupply of two launching gantries, their assembly, erection and commissioning as well as theerection of precast segments for 145 spans including all prestressing work. Work also includedall associated temporary works and the relocation of the gantries. The maximum span lengthwas 35m and the weight was 407t. The spans were built from precast segments, with thesimply supported spans erected using the span-by-span method. The challenging viaduct hadto accomodate a tight radius of 150m and a 4% longitudinal gradient. VSL was closely involvedwith the designer at all stages of the project to achieve the most efficient, reliable and rapidconstruction. Later stages of the project required VSL to come up with further special methodsto launch the bridge over portals, in an operation that had not been part of the original plan.

Once again, VSL provided excellent engineering solutions that helped the designer and maincontractor achieve the objectives without many changes to the permanent works.

Boosting Chennais transport

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strip sheathing. This reduced frictionleads to a better spread of the PT-force and hence to a direct savingin the amount of PT strand, the needfor less or lighter anchorages,shorter installation times for thread-ing, stressing and grouting opera-

tions.These savings will vary depending onthe nature of the structure but, as anindicator, reductions of up to 15% inPT-steel are possible. The lower fric-tion has also been proved to have apositive impact on fatigue behavior.With the latest revision of the sys-tems European technical approval,VSL has extended its PT-PLUSrangewith two new diameters, 65mm and85mm, in order to optimise the ductsfor intermediate tendon size.

PT-PLUSin buildings:increased productivityTwo VSL systems have combined tobecome a winning team for slabprojects. VSLab S and PT-PLUShave an optimised design thatranges from 6-2 to 6-5 tendons andcomes with a full set of fast-clip-ping accessories, reducing thework on the critical path to a mini-mum. The speed of installation is amajor advantage for todays fast

production cycles. The flat duct canbe delivered to site in continuouscoils and the full tendon length can

Almost 10 years ago, the FederationInternationale du Bton (fib)intro-duced in its bulletin 33 report theconcept of defining a protectionlevel (PL) applied to post-tensionedtendons and categorised the levelsas PL1, PL2 and PL3. With proper

material selection, the right instal-lation methods and skilled and ex-perienced staff, good corrosionprotection can be achieved formoderately aggressive environ-ments (PL1). For a more aggres-sive atmosphere, full encapsula-tion of the tendon is required andthis is achievable by using leak-tight grout caps and PT-PLUSpolymeric ducts.

PT-PLUSin bridges: material

savings and lower frictionPT-PLUSwas first installed in 1991when 113km of 100mm-diameterducting was used on the StorebltBridge in Denmark. Following thatpioneering bridge, PT-PLUSductshave been installed on hundreds ofprojects in all kinds of environments.The resulting experience backedup by dozens of tests - shows that thedesign friction coefficients forPT-PLUSducts can be considered35% lower1than for galvanized steel

be spanned in just one piece, elimi-nating the need for duct couplers.Not only is the cost of the coupleritself saved, but also the labourcosts are reduced. In a typical 30m-

long tendon, only two fast-clip con-nections to the trumpets areneeded. In contrast, classic steelducting requires six joint connec-tions -duct and duct-trumpet. A fullset of other accessories is availablefor situations where intermediategrouting points are needed orwhere H-anchorages have to be in-stalled.n

POLYMERIC DUCTS

PT-PLUS forenhanced durability

r&d


MahaNakhon:newcomer onBangkoks skylineMahaNakhon is a new 77-storey high-risecomplex located in the heart of BangkoksCentral Business District.

The combined use of VSLabS 6-3 andPT-PLUSis contributing to achieving theaccelerated pace set by a tightconstruction programme that targets

completion of the new Bangkok landmarkin 2015.1 = 0.12 vs = 0.18 according to PT-PLUS

Swiss Technical Approval

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ith the number of cable-stayedbridges soaring, VSL has been play-ing an important role in supportingcontractors in construction and de-

sign checks for these projects. Anextensive range of services is of-fered and VSL also assists consul-tants with the design of stay-cablecomponents such as anchorages,connection detailing, saddles, de-viators and dampers. Two types ofdampers are now used to mitigatevibrations on cable-stayed bridges.

Friction or visco elastic?The VSL Friction damper appliesthe same principles used in disc

brakes, dissipating the energythrough friction generated betweentwo friction partners. The first is a

MITIGATING VIBRATIONS

Disk brakes or rubber pads?

technical report

pair of sliding discs connected via acollar to the tensile member of thestay. It is sandwiched by the secondpartner, a specially developed com-

posite pad supported by a pair ofspring blades that are connected tothe external structure of the guidepipe. The VSL Friction damper pro-vides high performance for criticalcases or where the damper has tobe placed close to the deck anchor-age relative to the overall length ofthe cable. It can easily be adaptedto all cable sizes, whether for anew installation or as part of aretrofitting solution. In addition toproviding an outstanding perfor-

mance, the VSL Friction dampersare activated only when needed.This prevents unnecessary wear on

Wthe damper under vibrations withsmall amplitudes that do not af-fect the stay cables performance.However, the VSL Friction damper

achieves its maximum perfor-mance almost immediately oncethe cable vibration has reached alevel that is critical for the cable orthe structure to which the damperhas been tuned. This damper is theperfect solution for long cables onstructures with a high risk of para-metric excitation.The VSL visco elastic (VE) dampersuppresses cable vibration by dis-sipating its kinetic energy throughplastic deformation of spe-

cial damping rubber pads. Eachdamper consists of a series of padsmounted between a moveable col-


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lar attached to the tensile elementof the stay cable and a fixed supportrigidly connected to the guide pipe.The high-damping rubber padshave a long design life and excel-lent fatigue resistance. Acceleratedageing tests have demonstrateda life expectancy of 60 years andthe pads have sustained 10 millionload cycles during fatigue testing.The damper requires only minimalmaintenance during its operatinglife. This allows it to be placed ifnecessary even at the pylon, wheremaintenance access is difficult and

expensive. The VSL VE damperpresents an outstanding combi-nation of simplicity, durability andaesthetic qualities. The installationand maintenance can be performedwith minimum effort and hardlyany traffic disturbance. As with theFriction damper, all componentsare two half-assemblies. The maincomponents consist of the collar

assembly, rubber pads, dampersupport and guide-pipe brackets.Generally speaking, the combina-tion of the two systems allows VSLto cover the whole range of cablelengths and damping require-ments.

Fully pre-assembledWhile the design concept has re-mained essentially the same overthe years, constant improvementshave been made to the connectingelements, damper supports, guide-pipe fixing parts and anti-vandal-

ism pipe details.Recent developments have includedfurther improvements in damperdetailing for faster installation andeasier maintenance. Dampers cannow be fully pre-assembled underfactory conditions with stringentquality control. Options include theavailability of dampers with specialmovement-limiting devices to pro-

tect both the damper and the cableagainst rare but extreme events.Another improvement concernsthe anti-vandalism pipe, which wasoriginally a continuous elementcovering the damper system. It isnow divided into several compo-nents to provide better access dur-ing damper installation and main-tenance.Friction dampers and VE dampersystems share identical externalcomponents, which allows bothtypes of VSL dampers to be used onthe same structure without visual

difference.Clients, manufacturers and de-signers have contributed to theseimprovements, which are the re-sult of invaluable feedback, com-ments and collaboration. The endresult is the ability to carry out pre-assembly, a simple configuration,better functionality and enhancedaesthetics. n

Composite pad

VE

pads

Collar

Oscillating

movement

Oscillating

movement

Sliding

disc

Moveable

collar

Spring

bladesFixed support

connected to

guide pipe

Friction damper VE damper

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CABLE-STAYED BRIDGE

Second Penanga landmark link

tech show


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Bridge:

VSL was awarded two subcontracts for the construction

of the main superstructure of the Penang Second

Crossing, one that included the supply and installation

of the stay cables system with saddles and dampers

at the main navigation span, and a second in joint

venture for the supply and installation of 13,000t of

post-tensioning required for the construction of theapproaches. A full-scale load test on the stay cable

section completed VSLs comprehensive contribution

to the 24km-long landmark, which links Malaysias

Penang Island to the mainland.

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Define the needs for a link to the mainlandPenang is a major rapidly growing hub in northernMalaysia for industry, commerce and tourism. This hasled to a major traffic bottleneck at the existing PenangBridge, badly restricting further development. A project tobuild a second crossing came to life to cross the PenangStrait from Penang Island to the mainland. ThePenang Second Crossing comprises a main cable-stayedsection approached by viaducts. The overall length of thebridge is 24km and its main span is 250m, flanked by117.5m-long side spans. The height of the pylons is100.6m, of which almost 68m is above deck level.

tech showCABLE-STAYED BRIDGE

1

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3

2

Use of overhead gantries for the span-by-span construction of the approachesThe viaducts are made up of twin parallel structuresand their length over water is approximately 17km.Each viaduct comprises a trapezoidal segmentalbox girder typically spanning 55m between piers.Construction by the match-cast segmental span-by-span method used four gantries to erect the8,092 precast segments. VSL formed a JV tohandle the 30-month post-tensioning and groutingcontract for approximately 13,000t of strands.

Use form-travellers to build the main spanThe deck of the main span was built with underslungtravelers. VSL supplied and installed all prestressingand the stay cables for the main bridge.

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Install the stays withinnovative methodsIn total, 144 stay cableswere installed together with

the VSL SSI 2000 SaddleSystem. The shortest stayis 44m and the longest is262m from anchorage to an-chorage. VSL used the pull-ing system method to installthe strands, with winchesplaced at the pylons andon the deck. Two wincheswere placed on top of the py-lon. One was for pulling thestrand from deck level at theside span to the entry face of

the saddle. The other pulleda winch cable from the mainspans deck on the other sideof the pylon. The strand be-ing installed from the sidespan was then attached toa pilot wire which was con-nected to the winch from themain span. This strand wasthen pulled through until itreached deck level on theother (main span) side. Therapid progress of construc-tion has demonstrated the

ease and the efficiency of theVSL stay cable system.

4

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Install dampers to mitigate vibrationVSLs Visco elastic dampers have been in-stalled on all 144 stay cables. The VE dampersuppresses cable vibration by dissipating itskinetic energy through plastic deformation ofspecial damping rubber pads. Each damper

consists of a series of pads mounted be-tween a moveable collar attached tothe tensile element of the stay cableand a fixed support rigidly connectedto the guide pipe.

5


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Prove structural integrityIn association with FT Laboratories, VSLinstrumented the bridge for and col-lected data during a full-scale load teston the main bridge to verify the structuralintegrity before the crossing openedto public. The test involved bringing17 trailer trucks, loaded to a total weightof 595t, onto the bridge to test the behav-iour of the cable-stayed section. Designof the load-test system was aimed atmeasuring the bridges static and dy-namic responses to vehicular loads, asspecified by the designer.

6

Install sensors and analyse the resultsThe deflections of the decks and pylons were measured by means of sensors installedon the bridge designed to collect all types of data, such as wind, temperature, bridgedeck acceleration, displacement, stress or strain, stay-cable forces and the tilt anglesof the pylons and piers. The measurements were transferred to a data acquisitionsystem via data loggers that collected information across a distance of 150m-180m.The collected data was transmitted to a control and display system for verification

and storage. All data collected from the load test have been compiled and comparedwith the theoretical figures provided by the designer.

7


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Copyright 12/2013, VSL International Ltd.Printed in France patented.

The information set forth in this brochure including technical and engineering data is presented

for general information only. While every effort has been made to insure its accuracy, this

information should not be used or relied upon for any specific application without independent

professional examination and verification of its accuracy, suitability and applicability. Anyone

using this material assumes any and all liability resulting from such use. VSL disclaims any and

all express or implied warranties of merchantability fitness for any general or particular purpose

or freedom from infringement of any patent, trademark, or copyright in regard to the information

or products contained or referred to herein. Nothing herein contained shall be construed as

granting a license, express or implied under any patents.

Printed on paper

from sustainably

managed forests.

MALAYSIAVSL Engineers (M) Sdn. Bhd.

KUALA LUMPURPhone: +603 7981 47 42

PHILIPPINESVSL Philippines Inc.MANDALUYONG CITYPhone: +632 722 1703

SINGAPOREVSL Singapore Pte. Ltd.SINGAPOREPhone: +65 6559 12 22

TAIWANVSL Taiwan Ltd.TAIPEIPhone: +886 2 2759 6819

THAILANDVSL (Thailand) Co. Ltd.BANGKOKPhone: +66 2 679 76 15 - 19

VIETNAMVSL Vietnam Ltd.HANOIPhone: +84 4 3976 5088

HO CHI MINH CITYPhone: +84 8 810 6817

Australia/

VSL Australia Pty. Ltd.NEW SOUTH WALESPhone: +61 2 9484 5944

QUEENSLANDPhone: +61 7 3327 0200

VICTORIAPhone: +61 3 979 503 66

SOUTH AUSTRALIAPhone: +61 8 8252 1900

TASMANIAPhone: +61 3 6249 3044

PERTHPhone: +61 8 9419 1119

Americas/

ARGENTINAVSL Sistemas Especiales deConstruccin Argentina SABUENOS AIRESPhone: +54 11 5272 87 52

BOLIVIAPostensados de Bolivia

SAN MIGUEL, LA PAZPhone: +591 2 27 70 338

BRAZILVSL Brasil Construo eRecuperao LtdaSO PAULOPhone: +55 113 521 7153/4

CANADACTT Stronghold CanadaTORONTOPhone: +1 416 477 1042

CHILEVSL Sistemas Especiales deConstruccin S.A.SANTIAGOPhone: +56 2 2571 6700

COLOMBIASistemas Especiales deConstruccin S.A.SBOGOTAPhone: +57 1 226 6230

MEXICOVSL Corporation Mexico S.A de C.VMEXICOPhone: +52 55 55 11 20 36

PERUSistemas Especiales de ConstruccinPeru S.A.LIMAPhone: +51 1 349 38 38

VSL Peru S.A.CLIMAPhone: +51 1 713 98 32

UNITED STATES OF AMERICAVStructural LLCBALTIMORE, MDPhone: +1 410 850 7000

Africa/

EGYPTVSL EgyptCAIROPhone: +20 2 344 19 00

SOUTH AFRICAVSL Construction Solutions (Pty) LtdJOHANNESBURGPhone: +010 492 1811

TUNISIAVSL TunisiaTUNISPhone: +216 70 72 84 73

Europe/

AUSTRIAGrund-Pfahl- und SonderbauGmbHHIMBERGPhone: +43 2235 87 777

CZECH REPUBLICVSL Systmy / CZ / s.r.oPRAGUEPhone: +420 2 51 09 16 80

FRANCEVSL France S.A. (Bouygues TPRF)LABGE

Phone: +33 5 33 65 96 59

GERMANYVSL Systems GmbHBERLINPhone: +41 58 456 30 30

NETHERLANDSHeijmans Civiel b.v.Span en VerplaatsingstechniekenROSMALENPhone: +31 73 543 6611

NORWAYSpennarmering Norge ASRUDPhone: +47 98 21 02 31

POLAND

VSL Polska Sp. Zo. oWARSZAWAPhone: +48 22849 22 09

Middle East/

SULTANATE OF OMANVSL Muscat LLC

MUSCATPhone: +971 4 885 7225

UNITED ARAB EMIRATESVSL Middle East LLCDUBAI, UAEPhone: +971 4 885 0004

DOHA, QATARPhone: +974 44 052 444

Asia/

BRUNEIVSL Systems (B) Sdn. Bhd.BRUNEI DARUSSALAMPhone: +673 2 380 153 / 381 827

CHINA PRCVSL Engineering Corp., Ltd.(China)HEFEIPhone: +86 551 382 29 18

HONG KONGVSL Hong Kong Ltd.CHAI WANPhone: +852 2590 22 88

INDIAVSL India Private Ltd.CHENNAIPhone: +91 44 4225 11 11

INDONESIAPT VSL Indonesia

JAKARTAPhone: +62 21 570 07 86

JAPANVSL Japan CorporationTOKYOPhone: +81 3 3346 8913

KOREAVSL Korea Co. Ltd.SEOULPhone: +82 2 553 8200

PORTUGALVSL Sistemas Portugal SAPAO DE ARCOSPhone: +351 21 445 83 10

Delegao NorteVILA NOVA DE GAIAPhone: + 351 22 371 18 80

SPAINVSL Construction Systems SABARCELONAPhone: +34 93 289 23 30

SWEDENInternordisk Spnnarmering ABVSTERHANINGEPhone: +46 10 448 11 42

SWITZERLANDVSL (Switzerland) Ltd.SUBINGENPhone: +41 58 456 30 30

SAINT LEGIERPhone: +41 58 456 30 00

TURKEYMega Yapi Construction &Trade Co. LtdANKARAPhone: +90 312 490 90 66

UNITED KINGDOMVSL System (UK) Ltd.LUTONPhone: +44 148 040 4401

Headquarters

VSL International Ltd.

Sgestrasse 76

CH-3098 Kniz

Switzerland

Phone: +41 58 456 30 [email protected]

VSLLOCATIONS

VSL Infrastructure Protection Ltd.

LONDONPhone: +44 207 803 3614

SINGAPOREPhone: +65 65 59 12 22

SYDNEYPhone: +61 2 94 84 5944

Intrafor Hong Kong Ltd.

CHAI WAN, HONG KONGPhone: +852 2836 31 12

DUBAI, UAEPhone: +971 4 885 7225

FT Laboratories Ltd.

PING CHE, HONG KONGPhone: +852 2758 48 61

VSL Offshore Pte Ltd.

SINGAPOREPhone: +65 65 59 13 05

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LINKING

DESTINATIONS

LAUNCHING

LIFTING

RECOVERING

Rio Ulla Bridge, Spain

Torun Bridge, Poland

Orno Bridge, Ethiopia

Documents

VSL news_2013_2