001 Brochure Stay Cables

8/18/2019 001 Brochure Stay Cables

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Stay cables


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Tensacciai started to develop its technology forcable stayed bridges in the eighties.The rst small cable stayed bridge was built in1988, leading the way to the development of thewedge-resin coated anchorage system that found

its mature application in the bridge over theGarigliano river in Formia.Later on the technical solution with waxed,polyethylene coated strands was adopted, ndingthe famous application of the worldwide knownErasmus bridge in Rotterdam, with huge stays of127 strands and lengths reaching morethan 300 meters.Through the years, a continuous improvementhas led Tensacciai to the construction of morethan 40 cable stayed bridges, using itsTSR stay cable system.One of the latest is the cable stayed bridge over

the Po river, designed for the high speed railwayline Milano - Bologna. It is the rst knownexample of this kind of structure.New challenges are foreseen for Tensacciai inthe incoming years: the most daring will be theerection of a cable stayed bridge over the Adigeriver in Italy with 169 strands stays, giving amaximum breaking load of more than 47.000 kN.At this moment Tensacciai is directly involved incable stayed bridges projects with Companiesor Subsidiaries in all ve continents.


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The TSR stay cable system consists of a bundle ofparallel seven-wire steel strands, with nominaldiameter 15,7 mm. Currently it is the mostutilised type of strand, but the system has beeneasily adapted to be used with different kinds,including epoxy coated strand.According to a principle of modularity, staycables of several sizes can be obtained, fromthe smallest (e.g. the 3TSR15) to the largest andmore complex ones (e.g. the 169TSR15).Stays are used in single and multiple spans

bridges, in arch bridges as hangers, but also insuspended structures and buildings.

As a specialized contractor with decades ofexperience in the eld, Tensacciai is able toprovide, through its Engineering Department,all services related to design, manufacturing,installation and monitoring of stay cables.Starting from the analysis of the wholestructure, design of stays is carried out,with shop drawings and specications formanufacturing, issue of installation procedures

with loads and elongations checking, togetherwith further engineering services.New and customized solutions are continuouslyreleased, in order to t into different projects.

Tensacciai takes care of all the installationoperations, with their own specialized teamsand equipment, taking full responsibilityand operating under ISO 9001 qualityassurance system.

Cable stayed bridge at Santa Apolonia railway station,Lisbon (Portugal)

Arch bridge over the Paranoà lake,Brasilia (Brazil)


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Stay components

Main materials involved are:• High-tensile prestressing steels as main

tensile elements (according to prEN10138

section 1-4, NF A 35-035, ASTM 416M)• Forged steels used for anchorages

and structural ones for tubes and saddlecomponents (according to EN 10083, EN 10025)

• Zinc or other corrosion-protective coatingson the prestressing steel or structuralsteel components

• Filling materials such as wax for theprotection of strands and anchorages

• Polyethylene sheathing on prestressingstrands

• High density polyethylene (hdpe) for free

length stay pipes• Rubber or poly-chloroprene rubber for guide

deviators or damping devices

Design of all the components of TSR systemis based on severe requirements for materialsand their performances, as requested by themost important international standards asFib “Acceptance of stay cable systems usingprestressing steels”,

3

2

1

PTI “Recommendations for stay cable design,testing, and installation” and SETRA“Cable stays – Recommendations of Frenchinterministerial commission on Prestressing”.

Cable stayed bridge over the Guamà river,Belém (Brazil)

Steel strands

Stay cable technology foresees the useof seven-wires steel strands with a nominaldiameter of 15,7 mm, characteristic tensilestrength of 1.860 MPa, and a nominal breakingload of 279 kN per strand.Low relaxation steel strands, according to

prEN10138-3, NF 35-035 and ASTM 416M, havethe following protections:

1 Hot dip galvanization • zinc coating: 250 350 g/m2, • applied before nal drawing of wires

(no loss of ultimate strength)

2 Wax lling around and within wires • quantity of wax: 5 20 g/m, • anti-corrosion layer provided with

adhesion properties, • lubricating against fretting fatigue

3 Bonded hdpe coating • minimum thickness of 1,5 mm, • UV stabilized, shock resistant, • extruded on strand


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Anchorages

Anchorages have to guarantee the proper loadtransfer from the cable to the structure.Hence they must withstand severe loadconditions, with dynamic actions due to vehiculartrafc, and wind forces acting on the freelength of the cable.For this reason they are continuously tested.Two kinds of anchorages are available:

adjustable, provided with a regulation nut,and xed.Both types can be used either on the pylonor on the deck, according to installationand project needs.Strands are gripped inside anchorages withspecially designed wedges, tested to the worstfatigue and efciency limits.Adjustable anchorages allow regulation of loadsanytime is needed, even during lifetime of thebridge with a special adjusting jack acting overthe entire anchorblock.Anchorages are also adapted to be used atdeviated stay congurations with saddles,for extradosed bridges.

Wax Box SystemWax box system is designed to create a sealedand hermetic chamber behind the anchorblock,where strands’ uncoated length is completelyprotected with wax injection.After strands installation and closing oftensioning operations, the device placed at thebottom of the chamber is packed,providing full tightness.Wax injection can then be performed, restoringthe layer of protection lost with removal of hdpecoating, necessary for wedge grippingof steel strand.Wax box system has been designed to be directlyassembled in factory on the anchorage, withsaving of time during installation phasesin the construction site.

Arch bridge in Dintelhaven,Rotterdam (The Netherlands)

169 strands TSR anchorage


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TSR Stay Cable System

Nut

Wax box system

Adjustable anchorage

Anticorrosive compound – Wax

Protection cap

Injection tube

Bearing plate


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Galvanized, waxed and hdpecoated strand

Deviation system

Damper system

Form pipe

Antivandalisme /Telescopic pipe


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Main dimensions

Fixed anchorhead

N° of

strands

Nominalbreakingload Fpk[kN]

Maximumworkingload45%Fpk[kN]

Maximumtestedfatigueload range(200 MPa)[kN]

ØA1[mm]

ØB1[mm]

D[mm]

E[mm]

F**[mm]

G[mm]

1.116

1.953

3.348

5.301

8.649

10.323

11.718

15.345

17.019

20.367

25.389

35.433

47.141

4

7

12

19

31

37

42

55

61

73

91

127

169

502

879

1.507

2.385

3.892

4.645

5.273

6.905

7.659

9.165

11.425

15.945

21.218

120

210

360

570

930

1.110

1.260

1.650

1.830

2.190

2.730

3.810

5.070

110

150

200

240

280

280

325

325

360

410

440

490

580

180

200

280

300

310

330

370

370

460

470

500

550

630

280

300

375

390

415

430

475

475

550

590

650

750

900

70

80

80

90

130

150

150

175

200

250

300

350

390

20

20

20

30

30

30

30

30

50

50

50

70

70

20

30

40

50

70

80

80

90

100

100

120

130

145

200

200

250

250

300

300

350

350

350

400

400

400

450

Adjustable anchorages dimensions shown allow a ± 20% variation of the maximumpermitted working load (45% Fpk) acting over the adjusting nut.* diameter to be conrmed according to the project** if bearing on concrete surface with fck = 36MPa and considering 60% of ULS load

C1[mm]


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Adjustable anchorhead

ØH[mm]

ØI*[mm]

ØA2[mm]

ØB2[mm]

ØL*[mm]

M[mm]

O[mm]

P[mm]

ØQ[mm]

ØR*[mm]

ØS*[mm]

ØT*[mm]

102

128

180

205

239

239

283

283

334

334

365

429

510

121

139.7

193.7

254

273

273

323.9

323.9

355.6

355.6

381

457.2

535

110

135

190

124

280

280

325

325

360

410

440

490

580

150

185

220

300

330

345

410

410

455

505

555

590

700

300

340

440

450

500

500

560

560

610

650

700

800

900

121

146

177.8

177.8

229

229

323.9

323.9

355.6

355.6

406.4

457.2

520

50

60

60

70

85

90

120

120

120

130

150

200

250

155

175

175

250

280

290

340

340

350

410

445

535

625

150

150

150

210

250

250

250

250

250

250

250

250

250

120

145

235

250

275

290

335

335

370

420

450

500

590

121

146

254

273

323.9

323.9

355.6

355.6

406.4

457.2

473.1

530

635

80

102

139.7

139.7

177.8

193.7

244.5

244.5

273

298.5

355.6

406.4

430

63

90

125

125

160

180

225

225

250

280

315

355

400

C2[mm]


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Stay components

Hdpe tubes

High density polyethylene (hdpe) sheath coversstay’s free length, providing a further protectionagainst external agents, including UV rays, tothe bundle of strands. Hdpe pipe is the perfectsolution to meet protection needs, according withEuropean standard EN 12201.Pipes are supplied with different thicknesses,diameters and colours, in tubes of a maximumlength of 11.8 m. that are welded on site, with

special equipments, by mirror welding to createthe continuous nal stay pipe.Weldings develop the same strength of themonolithic pipe section.Three kinds of hdpe tubes are available:• with a smooth external surface,• with helical llets on surface,• with lengthwise llets on surface.The two last ones are recommended to reducedynamic effects due to rain - wind interactionphenomena, decreasing the risk of stays’dangerous vibrations.

Tubes can be provided in several differentcolours, meeting different designers’aesthetic needs.


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Damper system

Vibrations’ control is very important toprevent dangerous phenomena of instability,amplication of loads and fatigue.Inside stay cables, it is assigned to properdevices.Tensacciai elastomeric dampers are placed atthe end of the form tube, near the connectionwith the antivandalisme tube or thetelescopic tube.

Each stay is planned to have a couple ofinternal dampers, one in the area close to thedeck and one up near the pylon.The damper works when the level of thecable vibration becomes critical.This system is easily adaptable to allcongurations and projects, and thanksto the high efciency, durability and lowmaintenance costs, it is the best solutionto reduce vibrations.Durability is guaranteed by the high qualityof materials and the anticorrosive treatment

applied on all components.

Standard elastomeric damper comprises both aneoprene ring damper with steel disks supportand a middle nylon disk providing deviation ofeach strand.With neoprene deformability it is possible

to absorb vibrations, maintaining a highserviceability of the structures in each situation.A second type of damper can be provided,designed with a steel clamp compacting allstrands together.The interposition of a hdpe sheath betweenstrands and clamp prevents from any possibledamage, allowing a simple and safeinstallation sequence.Damper is inserted inside an externalsteel tube, which allows to movethe whole system on stay’s real axison the bridge and x it through

special anges: on site adjustmentcan be easily performed.

HDPE sheath

Hdpe coated,waxed, galvanizedstrands

Neoprenedamper

Externalsteel tube

Steel

clamp

Hdpe coated,waxed,galvanizedstrands

Neoprenedamper

Steeldisk

Steeldisk


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Installation

Installation of the TSR system is alwayscarried out by worldwide experiencedTensacciai teams, taking care of all phasesthanks to many decades of experience inthe eld. The fastest installation is alsoguaranteed by means of specially designedinstallation equipment.Preliminary operations are the welding of thehdpe tubes to the nal length and the cuttingof strands, starting from coils, over specialbenches to reach right marked measures.

With the anchorages already placed at pylonand deck level, the hdpe tube is lifted with atower crane and the rst strand is threadedwith special winches, following a denedsequence.Stressing is carried out while placingstrands, one by one, with the use of a specialTensacciai monostrand jack, providedwith system of measuring of loads andelongations.


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This step is carried out using the iso-elongationprinciple: stressing is done reading the positionof marks placed over strands, with guarantee ofsame load acting over the full bundle, throughsame position of marks.

One installed the entire stay, further steps ofstressing with monostrand jack maybe carried out.Anyhow nal small regulations of loadsare performed with the use of a Tensacciaiadjusting jack, acting directly over theadjustable anchorage and turning the nut tillnal position.Once completed stressing operations, injectionof anchorages with wax is carried out afterplacing of protection caps.Then nal closing of antivandalism and

telescopic tubes is carried out.

4-7-12

19-31-37-42-55

61

73

91

127-169

N° Strands A[mm]

L max[mm]

C min[mm]

425x425

585x585

650x650

705x705

750x750

950x950

950

1165

1165

1295

1320

1850

1005

1170

1180

1240

1275

1455


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Saddle System

Through the years Tensacciai has beendeveloping its technology for saddles, both forcable stayed bridges and extradosed bridges, inresponse to issues with existing saddle designs,relating to fatigue, fretting corrosion andreplacement of the cables.One of the great advantages of the TSS systemis that it allows designers to simplify the pylonstructure and use very slender proles toachieve an attractive appearance.

Two different kinds of saddles can be provided.The TSS-B type is composed of a rectangularsteel box lled with a high-strengthcompound.Design ensures high friction betweenthe cable and the saddle.Full cables can be replaced while strandscan be tensioned independently duringinstallation phases.The new Tensacciai Saddle system TSS-T is amultitube saddle based on the use of protected

strand which takes up the asymmetric frictionalloads through the strands.Each strand is deviated individually in a specictube, giving the following advantages:• complete continuity of corrosion protection,• possibility of individual replacement of strands,• fatigue resistance identical to a standard stay

cable anchorage.

Shearkey

Externalsteeltube

Internalsteel tube

High-strengthcompound

Wax box system

Removable steelplate

Telescopic pipe

PE coated galvanizedstrands

Cable stayed bridge over the Loing river,Nemours (France)


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Suspended bridges

Tensacciai suspended bridge system has beendesigned to use seven wire steel strands both forsuspension cables and vertical hangers.Special strand, epoxy coated with silica powderand hdpe coated, is used for suspensioncables, providing the highest level of corrosionprotection.Vertical hangers are connected to suspensioncables through special shape steel clamps,

transmitting forces by friction.This system has been severely tested in orderto verify ultimate limit shear loads and fatiguebehaviour, providing excellent results.Connecting clamps allow hangers to adapt theirposition depending on actual geometry of thebridge during installation.Saddles on top of pylon have been designed inorder to minimize shapes and manufacturingprocesses, starting from simple steel plateswith right shapes.

Suspended bridge in Chihani (Algeria)


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Monitoring

Monitoring of stay cables is important during allservice life of the bridge, and it becomes criticalin many cases.Monitoring of loads can be carried out withthe use of permanent load cells placed overanchorages.They can be of two different types:• monostrand, where load cell is placed only

over one strand of the anchorage and givingfull load of the cable as extrapolationof the single strand load,

• annular, resting directly beneath the nutof the adjustable anchorage and providingreadings of the load acting over the entire stay.

All load cells are designed to minimizethe sensitivity to eccentric loads andbearing surfaces.They can be connected to an acquisition datasystem, providing summary of the readingstaken from different cells.In such a way full monitoring of all stayscan be performed, giving a real time situationof the bridge during lifetime.

Further monitoring systems can be provided,like the innovative radar detection system, thatallows checking of loads and displacementthrough interferometric radar devices.This new cheaper system guarantees properreadings and reduced jobsite activities.

Annular load cell foradjustable anchorage

Cable stayed bridge over the Po river,high speed railway line Milano – Bologna, Piacenza (Italy)

Nut

Adjustable anchorage

Load cell


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Testing

Through the years an imposing test campaignon stay cables has been carried outby Tensacciai.Tests have been carried out not only over fullscale assembled cables but also over singledevices, like wedges, anchorages and dampers.Italian and International worldwide knownlaboratories have been chosen for testing,such as the EMPA laboratoriesin Zurich (Switzerland),the European Community JRC in Ispra (Italy),

the University of Munich (Germany).Tests have been performed according toInternational Standards like the PTI Stay CablesRecommendations or FIB Acceptance criteriafor stay cables.Sizes of cables tested varies from 16 up to 91strands, not only with axial set up but alsowith deviated one.Stays have been submitted to deviated fatiguetests, with stress range of 200 MPa andpulsating transversal displacement leading tocyclic angular variation of 0,5°, repeated morethan 2 million times.

Results have shown excellent fatigueresistance, with cross section of stayswithstanding wire breakages far below 2%.Subsequently stays have been brought tofailure, performing the usual efciency tests:results of more than 95% of nominal breakingload of the cable have been achieved.Testing campaign is still on the run, to checknew design choices and improve productsand performances.

European Commission Joint Research Center in Ispra (Italy)deviated fatigue and tensile test over 91 TSR stay cable


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Bridges

Cable stayed bridge over the Po river,high speed railway line Milano – Bologna, Piacenza (Italy)


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Cable stayed bridge Otavio Frias de Oliveiraover the Pinheiros river,Sao Paulo (Brazil)

Cable stayed bridge over the Sangone river,Giaveno (Italy)


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Bridges

Arch bridge over the Twente channel,Eefde (The Netherlands)


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Cable stayed bridge over the Paranaiba river,Carneirinho (Brazil)

Cable stayed bridge Jura overpass,Desnes (France)


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Bridges

Cable stayed bridge Kwanza, Barra do Kwanza (Angola)


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Cable stayed bridge over the Guamà river,Belém (Brazil)

Arch bridge Shaikh Khalifa Bin Salman,Hidd (Bahrain)


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Footbridges

Footbridge in Jesolo (Italy)

Footbridge in Melegnano (Italy)


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Footbridges

Footbridge in Gemelli hospital, Rome (Italy)

Footbridge in Vaiano (Italy)


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Head Ofce:via F. Vegezio, 1520149 Milano (Italy)

tel. +39 024300161fax +39 [email protected]

Ofce in Rome:via Lutezia, 200198 Roma (Italy)tel. +39 0632111820fax +39 [email protected]

Factory:via 25 Aprile, 8/10

20016 Pero, Milano (Italy)tel. +39 0238100064

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001 Brochure Stay Cables

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