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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
3
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.
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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.
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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.
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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
Mult ist rand Post -Tension ing
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.
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Duct B
Duct A
Grout tube
Mult ist rand Post -Tension ing
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
Mult ist rand Post -Tension ing
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.
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Bonded Slab Post -Tension in g
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.
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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.
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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
Bonded Slab Post -Tension in g
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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.
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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.
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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.
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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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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
Interstate 895 - Richmond,VA
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 895 - Richmond,VA
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