prestressing

1

PRESTRESSING

OF THE BRIDGES

2

PRESTRESSING SYSTEM INTERNAL TENDONS

(led inside the concrete structure) top straight tendons bottom straight tendons curved tendons inside webs horizontal straight tendons inside webs

EXTERNAL TENDONS (led outside the concrete structure)

running free inside the boxgirder

3

Types of the tendons

4

INTERNAL TENDONS

15 pc strand / tendon Dstrand = 0,6” (15,2 mm ) Astrand = 150 mm2

Type ST 1670/1860 N/mm2

Finit = 2973 kN / tendon Dout = 95 mm corrugated sheathing Anchorage system :

DYWIDAG SI (DSI) MA 6815 (Multiplane anchorage)

pressure grouting with cement grout

5

INTERNAL TENDONS AND ANCHORAGE SYSTEM

Dywidag SI MA 6815 anchorage systemCorrugated sheathing

Corrugated sheathing

Plastic trumpet

Ribbed anchor body

Wedge plate

Groutcap

6

INSERTION OF THE STRANDS

INTO DUCTS

Strandpushing device

Strand in

Insertion into the web

t

Insertion into the bottom slab

Strand out

8 m/s

7

PRESTRESSING OF THE INTERNAL TENDONS

Wedge plates

Wedge plates

Inserted tendons prepared

for prestressing

Hydraulic jack for prestressingHoZ 4000 ( kN )

stroke=250 ( mm )

8

EXTERNAL TENDONS

VORSPANN TECHNIK TENDONS ( double-extruded )

4 X VT-CMM 04-150 D band / tendon (16 pc.strand / tendon )

Dstrand = 0,6” (15,2 mm ) Astrand = 150 mm2

Type ST 1570/1770 N/mm2

Finit = 2973 kN / tendon Anchorage system :

VORSPANN TECHNIK VT CMM 16X150 anchor block

9

EXTERNAL TENDONS

VT-CMM BAND

VT-CMM 04-150 D

VT-CMM 02-150 D

10

DEVIATORS OF THE EXTERNAL TENDONS

Top deviator Top deviator

Bottomdeviator

External tendon

Bottomdeviator

LONGITUDINAL SECTION

11

INSERTION OF THE EXTERNAL TENDONS

Reels of bands

Pulling of the tendon

into the

boxgirder

Tendons inside the boxgirder

on temporary flying support

12

DEVIATORSTendons across

the deviatorTrumpet seal for

VT-CMM 4x04-150D

tendons

at the anchorage

VT-CMM 4x04-150D

tendon

Spare hole for tendon

13

PRESTRESSING OF THE

EXTERNAL TENDONS

ANCHOR BLOCK

Tensioning by means of VT 4000 ( kN )

prestressing jackstroke= 200 ( mm )

14

SAMPLES FOR THE APPLICATION OF EXTERNAL TENDONS

Anchorages inside a boxgirder

at a stiffener - tendons for launching

Tendons at top deviator