vsl construction systems us

8/8/2019 VSL Construction Systems US

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VSL

V S L C O N S T R U C T I O N S Y S T E M S

POST-TENSIONING

STAY CABLES

STRENGTHENING

HEAVY LIFTING

FORM TRAVELERS

A Structural Group Company


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VSL

About VSL 2

Multistrand

Post-Tensioning 4

Bonded Slab

Post-Tensioning 11

Monostrand

Post-Tensioning 16

External

Post-Tensioning 18

Stay Cables 20

Strengthening Systems 22

Heavy Lifting 24

Form Travelers 26

About Structural Group 28


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VSL

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Interstate 895 - Richmond,VA

Clinker Silo - Union Bridge,MD

Erie Zone 3 Tank - Erie ,CO

About VSL

As the recognized leader in post-tensioning and relatedengineering, VSLs construction systems have beenused throughout the world since 1956. As a pioneerin introducing post-tensioning technology to theUnited States, VSL designs, manufactures, and installspost-tensioning systems and components, and providesspecialized construction systems.

VSL has utilized these systems to build, repair, andstrengthen bridges, buildings, tanks, and special

structures throughout the United States. VSLs systemsare technically proven and have earned a well-deservedreputation for their quality and reliability.

Post-tensioning is VSLs core business. Multistrand andmonostrand systems are used in every area of concreteconstruction. The post-tensioning principle is alsoapplicable to stay cables and external tendons. VSLsunderstanding of prestressing has also led to thedevelopment of the VSL heavy lifting technique whichprovides safe and cost-efficient solutions for lifting andlowering of large and heavy loads. In addition, VSLoffers form travelers for construction of balancedcantilever concrete bridges.


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VSL provides technical support during theplanning and construction phases of projects.Our comprehensive range of services includesfeasibility studies, preliminary designs, alternativeproposals, detailing, project coordination, andcontractor consulting. VSL can also execute thework utilizing VSL personnel and equipment.These services aim to provide the best solutionadapted to each customers requirements.

As part of the Structural Group, the nation sleading specialty contracting organization, VSLcan deliver innovative solutions from operatingcenters throughout the United States. TheStructural Group businesses perform a w ide rangeof projects involving the construction, repair,strengthening and protection of industrial facilities,commercial properties, public infrastructure, andmunicipal structures. For additional information onStructural Group, please visit www.structural.net.

VSL

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Sunshine Skyway - Tampa-St. Petersbur g,FL

Wi lliam Natcher Bridge - Owensboro, KY

Icehouse - Denver,CO


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The VSL Multistrand System is characterized by thefollowing features:

q standardized tendon units using up tofifty-five 0.5" (13mm) or 0.6" (15mm) diameterstrands;

q wide selection of anchorage types;q steel or plastic PT-PLUSTM ducts;q high-performance cement or other types

of grouting;

q tendons manufactured on-siteor in the plant;q no need to determine tendon length

in advance;q simultaneous stressing of all strands in a

tendon;q stressing carried out in any number of phases;q simple and reliable equipment for

installation, stressing and grouting .

VSL Multistrand System Components

VSL Anchorages

Technical data and dimensions are provided in the Appendix.

For clarity and simplicity, spirals are not shown in the pictures. However, they form an integral part of theanchorage. For more detailed information, see VSLsReport Series on Detailing for Post-Tensioning.

The SO, SA and VSLAB+ are our standard anchorages for bonded slab post-tensioning. They are alsooften used for bridges, buildings, tanks and other structures.

VSL

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Vent

Dead-end anchorage

Grout tubeGrout tube

Stressing anchorage DrainDrain

Mult ist rand Post -Tension ing


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Stressing Anchorage: VSL Type ES

This revolutionary anchorage has a composite bearingplate (metal - high performance concrete) and is lighter,smaller and easier to handle.It comes in 3 different configurations:ES- STANDARD for normalapplications, ES- PLUSusingVSLs PT-PLUSTM duct system forenhanced corrosion protection orimproved fatigue resistance, andES- SUPERto provide an electricallyisolated tendon. Equipped with anadditional retainer plate, the ESanchorage can also be used as adead-end anchorage.

VSL

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Strands

Wedges Anchor head

Bearing plate

Duct

CStrumpet

Permanent

grout cap (optional)

Grout connection

Anchor head

Wedges

Strands

Duct

Bearing plate

Grout tube

Duct

Sleeve

Strands

Wedges

Anchor head

Bearing plate (steel)

Stressing Anchorage:VSL Type E

The prestressing force is transferred to the concrete

by a mild steel-bearing plate. If equipped with anadditional retainer plate, the E anchorage can alsobe used as a dead-end anchorage.

Stressing Anchorage: VSL Type EC

This compact and easy to handle anchorage system allows prestressing force to be transferred throughtwo flanges. If equipped with an additional retainer plate, the EC anchorage can also be used as adead-end anchorage.


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Coupler: VSL Type K

This fixed coupler is used for connecting toa tendon that has already been installed andstressed. The strands are anchored usingcompression fitt ings positioned onto thecoupling head grooves.

Intermediate Anchorage:VSL Type Z

Intermediate anchorages are used for thosetendons where the ends cannot be anchoredusing normal stressing anchorages. Theanchor head is loosely placed in the

blockout and moves during the stressingoperation on the tendon axis. Z typeintermediate anchorages are used:

q for pressure shaft and pressure tunnelring tendons, avoiding the use ofinternal buttresses;

q for silo and reservoir circular structurering tendons, avoiding the use ofexternal buttresses;

q for transverse bridge deck prestressingwhere, for aesthetic reasons, externalanchorage blockouts are undesirable;

q for frame, arch and shell structure

tension ties where there is no or limitedaccess to end anchorages.

VSL

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Retainerplate

Wedges

Duct

Tension ring with anchors

Grout tube

Grout tube

Wedges

Bearing platetype EC, ESor E

Tension ring

Sleeve

Coupling head K

Duct

Compression fittings

Steel band


Anchor head type Z


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VSL

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Dead-End Anchorage:VSL Type P

This type of anchorage is used where theprestressing force has to be transferred tothe structure at the far end of the tendon .It consists of a folded plate incorporatingholes for the strands to pass through. Thestrands are anchored using compression

fittings bearing on the plate. The compressionfittings are locked into position by aretainer plate.

Where the force can only be transferred tothe concrete using a bearing plate,polyethylene tubes can be used to sheaththe strands between the end of the ductand the bearing p late.

Dead-End Anchorage:VSL Type T

The t ransfer of the prestressing force ispartially achieved by bonding the strands tothe concrete, and partially by the individualanchor casting. The spiral and tension ringconfine the stresses due to deviated forcesacting on the concrete.

P-plate

Compression fittings

Retainer plate

Duct

Tension ring

Seal

Grout tube

Type T anchorage

Grout tube

Duct

Tension ring

Seal


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Dead-End Anchorage:VSL Type L

This type of anchorage is used for tendons installedafter the concrete is placed and where there is noaccess to the dead-end. It is often used for verticaltendons in reservoir walls, for connecting piersegments to piers in segmental bridge construction,or for horizontal tendons in slabs or foundationmats. The strands are installed into the duct afterconcrete placement and simultaneously stressedusing jacks at both ends.

Dead-End Anchorage:VSL Type LD

When loops with a smaller radius are required, VSLType LD Loops are available with a 23" (584mm)radius. The tendon sizesavailable are the same asType L the difference isin duct configuration asindicated.

Dead-End Anchorage:VSL Type AF

This type of anchorage is used for vertical tendons

that must be installed after concrete placementwhere the prestressing force has to be transferredto the structure at the lowest end of the tendon

and when there is no access to thedead-end anchorage. The tendon isgrouted in two stages. The strands,with compression fitt ings at theirends, are bonded to the load-transferring casting using specialcementitious grout. After stressing,the tendon is grouted.

Sheathing and CorrosionProtection

Generally, corrugated steel ducts with a minimumwall thickness of 26 gauge are used.

However, the VSL PT-PLUSTM System w ith itscorrugated duct and plastic coupler can provide anumber of important advantages when comparedwith conventional ducts, such as:

q greatly enhanced tendon corrosion protection;q improved tendon fatigue resistance;q reduced sensitivity to stray electric currents;q reduced tendon friction;q electrical isolation when used with special ES

anchorages.

The PT-PLUSTM

System is suitable for all applicationsbut, given its specific characteristics, is bestadapted to:

q transverse tendons in bridge deck slabs;q tendons that are close to the concrete surface;q railway bridges and other structures that are

subject to fatigue loadings or stray electriccurrents;

q structures where a severe corrosiveenvironment may be expected;

q tendons that need to be electricallymonitored throughout the structuresservice life.

VSL

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Duct B

Duct A

Grout tube


Duct sized such that onlytwo (2) layers of strandoccur in the loop.


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Stressing

The unique feature of the VSL Post-Tensioning Systemlies in its special wedge locking procedure. The wedgesalways remain in contact with the strands during thestressing operation. As the pressure in the jack is released,the wedges automatically lock in the conical holes of theanchor head.

Grouting

The objectives of the VSL Grouting System are to preventcorrosion of the prestressing steel by filling of all voidsand cavities in the tendon and to fully encapsulate thesteel in an alkaline environment, as well as achieve aneffective bond between the prestressing steel and thesurrounding concrete member. This is achieved through:

q Careful selection of cement, water, and admixtures;q Continuous quality assurance and quality control

processes and measurement;q Selection of mix design and procedures adapted to

the selected materials, environment and equipment;q Performance of the grouting by trained VSL

Grouting Technicians.

VSL

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Placing of anchor head

Positioning of jack

Grouting of tendon

Str essing,measuring,seating of wedges


Placing of anchor head and wedges

Positioning of jack

Stressing

Seating of wedges


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Construction Sequence

Todays building owners and designers needto provide a high level of structural flexibilityto meet changing user requirements.

Post-tensioning provides greater spans withreduced structural beam depths, resulting inlarger column-free areas. As a result, internallayouts are not dictated by tight column grids.

Positive deflection and crack control and, ifnecessary, joint-free slabs, free designers fromthe limitations of conventional reinforcedconcrete structures.

The VSL Bonded Slab Post-Tensioning Systemhas been used in many buildings andstructures throughout the w orld. The systemuses up to five strands contained in flat-shapedducts, and anchorages. Strands areindividually stressed and gripped by wedgeaction. After stressing, the ducts are filled with

cement grout that fully bonds the strands tothe surrounding concrete.

VSL

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Cottonwood - Salt Lake City,UT

Bonded Slab Post -Tension in g

Mt. Rushmore - Keystone,SD


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Selected Design Considerations

q Spacing of tendon supports: 2.5 ft to 4 ft (0.8 to 1.2m) (conventional steel ducts)2 ft (0.6m) (PT-PLUSTM plastic ducts)

q Minimum curvature radius: 8 ft (2.5m) (vert ical profile)50 ft (15m) (horizontal profile)

q Minimum straight length at anchorage: 2.5 ft (0.8m)

q A wedge draw-in of approximately 0.25 in. (6mm) occurs at lock-off

q Friction losses can vary fairly widely from one tendon to another and from one structure to another.This depends on factors such as surface condition of strands, duct types and surface condition,material properties, installation methods and on-site workmanship. The following values may beassumed for design.

Tendons in standard steel ducts: = 0.20k = 0.0002/ft (0.0007/m)

Tendons in plastic ducts: = 0.14k = 0.001/ft (0.0033/m)

The PT slab method allows designers to reduce building heights or to increase free heights between floors.

VSL

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Free height

Free height

Free height

Free height

Height saving

Traditional Design PT Slab Design


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VSL requires pre-placement of strand in flat duct tendons prior to concrete placement.

VSL

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Stressing Anchorage:VSL Type SO

Grout tube

Wedges

Strands

Recess former

Flat duct

Anchorage body

Trumpet

VSL Type SA Anchorage

VSL Type N Anchorage

Grout tube

Grout tube

Tension ring

St rands Wedges Cast in bear ing plat e

Duct

Flat duct

Anchor head


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With the VSLAB+System, the post-tensioningstrand is protected by a high performance groutand a true encapsulation system. The grout ventsdo not exit on the slab wearing surface, but only atthe slab edge. The slim design of the bearing platewill easily fit in a 5.5 inch (140mm) thick slab. VSLfield technicians ensure proper placement, stressingand grouting of the VSLAB+ System.

The patented VSL Venturi System ensures completegrout filling at the intermediate anchoragelocations.

VSL

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VSLAB+System

End Anchorage

Grout cap

End anchor headBearing plate

Half shell

Duct

Clip

Grout vent

Wedge

Gasket

Bearing Plate withPocket Former



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VSL

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Duct

High performance groutEncapsulated str and

Coupler Assembly(Intermediate)

Stress End with Vent

Grout Detail


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The VSL Monostrand System has advantagessimilar to those of the VSL Bonded Slab Post-Tensioning System. The VSL Monostrand systemuses 0.5" (13mm) and 0.6" (15mm) diameterstrands. The strands are given a coating ofpermanent corrosion-inhibiting coating and areenclosed in an extruded plastic sheath. The greaseand plastic provide double corrosion protection,as well as preventing any bonding between thestrands and the surrounding concrete.The plasticsheath is polyethylene with approximately 50 milwall thickness. To ensure continuous corrosionprotection in aggressive environments, specialsleeves are used to join the sheaths to the anchor-ages and each anchorage is provided with aprotective cap. The VSLMonostrand System featuresfactory-applied corrosion protection, very lowfriction losses, and full utilization of the structuraldepth. These light, flexible monostrands can beeasily and rapidly installed, leading to economicalsolutions. Detailed information is given in VSLsPost-Tensioned Slabs publication. With modifica-tions, the VSL Monostrand System can also be

used for post-tensioning masonry walls.

VSL

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Permanent corrosioninhibiting coating

Plastic sheath Strand

Bristol Towers - Miami, FL

Monostrand Post-Tensioning

Monostrand Specifications:

q 0.5" (13mm) and 0.6" (15mm) diameterstrand in accordance with ASTM A 416.

q permanent corrosion-inhibiting coatingand plastic sheath in accordance with PTIrecommendations.


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Recommended Design Values

Spacing of tendon supports: 2 ft to 5 ft(0.6 to 1.5m)

Minimum curvature radius: 8 ft (2.5m)

The following friction cfficients may be assumed: = 0.05k = 0.0014/ft (0.0046/m)

Reinforcement of theAnchorage Zone

In addition to the slab reinforcement requiredby the design, additional reinforcement isnecessary in the force distribution zone behindeach anchorage. Details should be establishedby the project engineer.

VStrandTMHeat ResistiveTendon

VSLsinnovative heat-resistive post-tensioningtendons have been developed to mitigate thedetrimental thermal effects of a fire on thestrength of the prestressing steel. Each tendonconsists of one or more steel prestressing strandscoated with a proprietary intumescent material.This coating provides a significantly greaterdegree of protection to the strand in the event of

a fire. These tendons are particularly well suitedfor strengthening of parking garages and otherstructures that are exposed to vehicular fires.

VSL

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Monostrand 2

Sleeve Monostrand 1

Coupling body

Coupling head andthreaded coupling

Installation piece

WedgesMonostrand

Sleeve

Anchorage body (casting)

Recess former

Installation nut

Sleeve

Dead-End Anchorage:VSL Type SF-6

Coupler:VSL Type SK-6

Twin ram jack

Anchorage body (casting)

Monostrand

Sleeve

Closure cap

Stressing Anchorage:VSL Type S-6

Stressing Jacks

VStrandTMTendon Detail

25 mil intumescentfire retardant coating

40 mil polyethylenesheathing

Reinforcing mesh

25 mil polyethylene

sheathing270k low-relax

7-wire PT strand

Grease coating


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External post-tensioning is well adapted to bridges dueto the resulting savings in construction costs and thehigh degree of corrosion resistance provided by thesystem. External tendons are easy to inspect and, if

necessary, replace. They are ideal for strengtheningexisting structures and, apart from their uses inbridges, can be used for a wide range of otherapplications, including buildings, silos, and reservoirs.

VSL External Tendons:

q strand bundle;q polyethylene ducts;q standard multistrand anchorages, or special

anchorages permitting easy tendon replacement;q grout.

VSL

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VSL External Post-Tensioning System Components

Stressing anchorage Strand bundle and sheathing Stressing anchorage

Ext ern al Post -Tension ing

VSL


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Saddles at Points of Deviation

A saddle at a point of deviation consists of:q a structural element capable of carrying the loads exerted by the tendon in the deviation zone;q a part ensuring the geometry of the deviation.

Globally, a saddle at a point of deviation must satisfy the following requirements:q withstand both the longitudinal and transverse forces that the tendon applies to it and transmit these

forces to the structure;q ensure, without unacceptable angular breaking, the connection between two straight tendon sections;q withstand movements of the external tendon during stressing without compromising the tendons

corrosion protection system.

When designing saddles, it is important to consider the following:Various solutions have been used in practice, as shown on the sketch. In most cases, saddles consist of apre-bent steel tube cast into the surrounding concrete or attached to a steel structure by stiffening plates.The connection between the free tendon length and the saddle must be carefully detailed in order notto damage the prestressing steel by sharp angular deviations during stressing and in service. It is alsoimportant that the protective sheathing be properly joined. If tendon replacement is a design requirement,the saddle arrangement must be chosen accordingly; i.e., double sheathing as shown on alternative(3) of the sketch below or by the use of a Diablo as shown on the alternative (4) of the sketch.

Minimum Tendon Radii

Minimum tendon radii as recommended in Table 1 must be followed in order to avoid damageto the prestressing steel and the plastic sheathings, as well as to the outer tubing. It is well establishedthat friction problems may occur if tendon radii are too small.

Table 1: recommended minimum tendon radii

Tendon size (VSL tendon unit) Minimum radius (ft) (m)up to 5-19 or 6-12 8 ft 2.50mup to 5-31 or 6-19 10 ft 3.00mup to 5-55 or 6-37 13 ft 4.00m

Saddle Arangements

VSL

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VSL


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Stay Cables

VSL Stay Cable SystemSSI 2000

VSL Stay Cable System

The VSL Stay Cable System was developed to meetthe stringent design, construction and maintenancerequirements of cable-stayed bridges. The VSL StayCable System includes:

qa tendon formed from multiple and parallel0.6" (15mm) diameter high tensile 7-wire steelstrands;

q a greased extruded plastic coating to eachstrand;

q an outer plastic stay pipe;q factory prefabricated anchorages.

The system features are as follows:q 29.0 ksi (200 MPa) high fatigue resistance at 45%

of tendon capacity over 2,000,000 load cycles;q high degree of corrosion resistance using

multi-layer corrosion protection;q an extruded coating providing excellent strand

corrosion protection during construction;q

individual strand encapsulation and sealingin anchorages;q easy installation of the strands into the erected

stay pipe (single strand installation);q all strands are parallel with no risk of twisting;q single strand stressing;q no requirement for on-site cable grouting;q easy tendon force monitoring and

adjustment throughout the cables service life;q ability to remove and replace individual strands

without dismantling the installed anchorages,or the entire cable at any time;

q system adapted for the future installation ofanti-vibration dampers.

VSL

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Sunshine Skyway - Tampa-St. Peter sburg, FL

Anchorage head and ring nut

12to

125m

onostra

nds

Dead-end anchorage

Individual VSL monost rand and stay pipe

Centering elastomeric device

Guide pipeTransition pipewith individualstrand protection

Bundle of monostrands

HDPEstay pipe

Grease or wax

PEsheath St rand

VSL


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Compactness

The reduced size of the anchorage componentsallows for easy installation and savings in the costof the structure.

Aesthetics

q using colored co-extruded stay pipes, differentcolors can be obtained;

q vibration damping devices can be placedinside guide pipes or stay pipes.

Dynamic Stability of theCables

q stay pipes can be equipped with external

helical ribs to suppress rain-wind inducedvibrations;q the stay cable system is easily modified for the

future installation of anti-vibration dampers.

Durability

A high degree of corrosion protection:q each strand is individually protected not only

in the stay pipe, but also in the transition partof the anchorage;

q individual anchorage sealing joints protecteach strand not only in service, but alsoduring bridge erection;

q VSLs Stay Cable System has the unique featureof providing complete encapsulation for eachindividual monostrand along the free lengthand into the anchorage.

Reduced Maintenance Costs

q easy corrosion control of anchoragecomponents;

q good access to vibration damping systems.

Stay Cable Installation

q system optimized for strand-by-strandinstallation, with easily handled, lightweightequipment and reduced construction loads onthe bridge during construction.

VSL

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Foss Waterway - Tacoma,WA

C&D Canal - Delaware

VSL


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VSLStrengthening Systems provide economicalsolutions for structures requiring load capacityupgrade or improvement due to change of use,deterioration, or construction defects.

Turnkey Solutions

VSL is a one-source solution for structural upgrades.Our systematic approach to the analysis, load testdesign and execution of strengthening projectsallows usto integrate our engineering, manufac-

turing and installation capabilities into a creative,efficient, timely and cost-effective approach.

VSL Structure Evaluation

RapidLoadTMTest

The RapidLoadTM testing procedure can beperformed to assess the capacity in a structuralmember that will undergo a change in use or toqualify the level of damage or deterioration that hasoccurred to that member. RapidLoadTM test may alsobe used to establish the service levels of a unique

design or verify the adequacy of a proposedstrengthening solution.

y y y y y y y y y y y y y y y

y y y y y y y y y y y y y y y

JackJack

LVTDReaction TrussReaction Truss

Test Beam

VSL

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Strengthening Systems

VSL Structure

Evaluation

VSL StrengtheningSolutions

VSL Installation

RAPIDLOADTM

Load Testing System

Document/DrawingReview

Visual Examination

ExploratoryInvestigation

Non-DestructiveTesting

Laboratory Testing

ExternalPost

Tensioning

CompositeStrengthening

EnlargementPlate

BondingSpan

Reduction

Structural Analysis

VSL StrengtheningSolutions

VSL Structure

Evaluation

VSL Installation

RAPIDLOADTM

Load Testing System

Document/DrawingReview

Visual Examination

ExploratoryInvestigation

Non-DestructiveTesting

Laboratory Testing

ExternalPost

Tensioning

CompositeStrengthening

EnlargementPlate

BondingSpan

Reduction

Structural Analysis


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VSL


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Heavy Lifting

For economic or technical reasons, todays civil

engineering structures and industrial plants areoften assembled from large, heavy, prefabricatedcomponents. VSL Heavy Lifting will often providethe most effective solution for projects where cranesor other conventional handling equipment cannotbe used.

Innovative Solutions

VSL can plan lifting, horizontal jacking, or loweringoperations and design the necessary temporarystructures needed to meet your requirements.

Safety

The safety of your personnel and work site is VSLsfirst priority. Our specialized hydraulic liftingequipment is designed to provide the highest levelof reliability, and VSL field services are based on atotal commitment to safety.

Flexibility

Our equipment includes a large number ofhydraulic strand units, jacks, pumps, control units,monitoring devices and modular lifting / jackingframes, giving us the capacity to perform virtuallyany project requiring lifting, lowering or horizontaljacking.

The VSL Service Package

Our approach is flexible, and the range of ourservices is tailored to the specific projectrequirements. They include:

q feasibility studies and preliminary consultation;q project design and planning;q design, manufacture, and supply of special

equipment;q leasing of VSL equipment and execution of work.

Escondida Copper Mine - Chile

Winfield Lock and Dam - Winfield,WV

VSL


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Proven Equipment forHandling Heavy Loads

The VSL Strand System

The main components of the VSL Strand Systemare the motive unit, the tensile member with theanchorage for the load, and the pump with itscontrols.

Motive Unit

The motive unit consists of a hydraulic center holejack with upper and lower anchorages. Duringlifting the jack is extended, causing the individualstrands of the tensile member to be gripped by theupper anchorage and thus to be moved upwards.

At the start of the pistons downward movement,the strands are immediately gripped by the loweranchorage. In this way, the load is raised using astep-by-step process. For low ering operations, VSLsmotive units may be equipped with an auxiliarydevice which automatically controls the openingand closing of the anchorages.

Tensile Member

The tensile member consists of 7-wire prestressingsteel strands with a 0.6" (15mm) nominal diameter.The tensile member is anchored to the load by aspecially designed end anchorage.

Hydraulic Pumps

VSL electro-hydraulic pumps can be manuallycontrolled or operated in groups from a central

control board. VSL has a wide range of pumps witheither single or multiple outlets. The characteristicsof these pumps ensure the synchronized movement

of the jacks. Pressure control devices allow forces tobe monitored at all times. The movement speedvaries according to the project and, if required, canbe in excess of 65 ft (20m)/hr.

Control & Monitoring Systems

The lifting of hangar roofs or of similar staticallyindeterminate structures usually requires that liftingmovements be precisely coordinated. This is achievedby specially designed, computer-based multi-pointmonitoring systems, which allow the operation tobe centrally controlled and monitored up to thefinal, precise height.

Special Hydraulic Equipment

Our range of equipment also includes a large

number of different hydraulic jacks. VSL can alsodesign and supply custom-built hydraulic systemsfor special applications.

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Seven Mile Bridge - Florida

VSL


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The VSL Form Traveler System is used for construc-tion of balanced cantilever concrete bridges. Theform traveler system is designed to provide a rigidframe to minimize deflections under load. VSLprovides a custom engineered, highly flexible formtraveler system for a variety of segment lengths,depths and structure configurations.

System Flexibility

The VSL Form Traveler System is designed for avariety of segment lengths up to 16.5' (5m), andcan support concrete and formwork loading upto 450 tons. The traveler system design canaccommodate w ide variations in segment length,height, web thickness and deck width andgeometry. Vertical deflections at the leading edgeof the traveler assembly are typically less than 1"(25mm) at maximum loads.

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Form Travelers

H-3, Nor th Halawa Valley Viaduct,Hawaii

Interstate 205 - Port land, OR


VSL


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System Operation

The VSL Form Traveler System is economical andefficient to use. The traveler is designed with pinnedconnections for simplicity of erection and disman-tling. Launching is accomplished by advancing thesystem forw ard on rails. The interior formw orkremains within the previously poured section inorder to facilitate the placing of the reinforcing steelin the bottom slab and webs of the new segment.The segment construction cycle can generally becarried out in 4-5 days. A typical segment cyclewould consist of the following steps:

1. The System is launched on rails to the newsegment location.

2. The external formwork is aligned, leveled andfixed into place.

3. Reinforcing steel is placed in the bottom slaband web walls.

4. The interior formwork assembly is advanced,and the top deck slab soffit and wall forms are

leveled and fixed into place.5. Reinforcing steel and post-tensioning tendons

are placed in the deck slab.

6. Concrete is placed in the bottom slab, webwalls, and deck slab.

7. The post-tensioning tendons are stressed.

8. The internal and external formw ork is strippedfrom the cast and cured segment, and the VSLForm Traveler is launched to the next segment.

VSL Services

VSL provides a variety of design, fabrication,material and installation services to the balancedcantilever construction process. Our engineering

team supports the custom design of the TravelerSystem to meet the needs of a specific project andbridge configuration. Complete system drawingsand operation manuals detail all aspects of traveleroperation for ease of assembly and safe operation.VSL is ready to provide technical assistance and fieldsupervision of traveler erection, launching, mainte-nance and dismantling. VSL construction forces canalso provide an expanded scope of services toinclude the supply and installation of the reinforcingsteel, formwork and post-tensioning systems.

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Wabasha Str eet Bridge - St. Paul, MN


Interstate 205 - Port land,OR


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VSL

VSL Operating Centers:

DALLAS, TEXAS1609 109th StreetGrand Prairie, Texas 75050972-647-0200Fax: 972-641-1192

DENVER, COLORADO4825 Van Gordon Street

Wheat Ridge, CO 80033303-456-9887Fax: 303-456-9796

WASHINGTON, D.C.8006 Haute CourtSpring field , VA 22150703-451-4300Fax: 703-451-0862

Structural Group Operating Centers

ATLANTABALTIMOREBOSTONCHICAGOCLEVELANDDALLASDENVERDETROITFT. LAUDERDALEHOUSTONINDIANAPOLISKANSAS CITYLAKE CHARLES, LANEW YORKPITTSBURGHSALT LAKE CITYWASHINGTON, D.C.

www.vsl.net

Copyrig ht 200 1 VSTRUCTURAL, Llc VSL-CS1 0/ 01 5M

A Stru ctural Group Company

vsl construction systems us

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