bridge girder intermediate diaphragms_1

8/22/2019 Bridge Girder Intermediate Diaphragms_1

1/5

14Prestressed

December 2004

Box Girder Diaphragm for CIP Prestressed Girder

Notes: Inset d iaphragm ____ mm to al low for prestress shortening. Bottom of b lockout should be located at or above the top surface of the bottom slab.Diaphragm > 40 skew i l lustrated.

Recommended Diaphragm Dimensions

)seergeD(wekS"a"noisnemiDmuminiM

tnemtubAtaegniHtA

41-0 009 008

92-51 0011 0001

44-03 0031 0021

55-54 0051 0041

B8-5

100 mm min fillet

See Bridge Design Details,page 8-32"a"

Abutment

#13 @ 250 mm

B8-5

#__ @ ___

#____ tot ____

1

2


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etric

Caltrans

Bridge Design Details

December 2004

Box Girder Cell Access

In post- tensioned concrete box girder br idges with tendons exposed in the cel ls, i t isnecessary to provide access to al l cel ls to permit removal of deck forms and also forfuture inspection of the tendons.

A m in im um of tw o m anholes per span shou ld be prov ided for fu ture access. Th is m aybe reduced for mu lti -span structures. M an holes are usua l ly located in shoulders orsidew alks, bu t access openings in the bo ttom slab are perm issible. Open ings ind iaphragms and webs shou ld be as la rge as possib le .

Temporary openings in the top or bottom slab shal l be permitted for removal of deckforms. Open ings in the top slab are preferred. Location and m axim um size sha l l be

show n and ind icated as op tiona l for the contractor. If po ssible, form lum ber should nothave to be moved through more than 2 open ings in d iaphragms or webs.

Permanently left- in-place galvanized, corrugated steel forms are an acceptableal ternative.

1250 m m x 1250 m m tempo rary open ings w i ll be perm i tted in top or bot tom s lab, w hereindicated, at con tractor 's option.

A

A

A A

600 mm min openings

Lap 20 dia (all reinforcement)

Section A-A

Girder Layout


3/5

14Prestressed

December 2004

Diaphragm Details for Precast Girders

A

A

ElevationElevation

B

B

Construction joint

ection B-BIntermediate Diaphragm

Section A-AEnd Diaphragm

Construction joint

C

Elevation

Form soffit of capand enddiaphragm as astraight linebetween edges ofgirders (see note 4)

See Note 2 (typ)See Note 1 (typ)

Section C-CEnd Diaphragm

Construction joint

Notes

1. #25 x 1200 mm dowels placedthrough 37.5 mm dia hole formedin girder, when diaphragms arecontinuous. Hole need not begrouted.

2. 25 mm dia bolts x 400 mm withinsert assemblies whendiaphragms are discontinuous.Bolts required for exterior girder.

3. Intermediate and enddiaphragms are to be placed 5days before placing deck. Thisnote appears on Std. Plan B0-5.

4. This note clarifies forming so as toprevent spalling problems of thinunreinforced concrete undergirders.

75 mm minchamfer cont.


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Caltrans

Bridge Design Details

December 2004

Stirrup Anchorage for Precast Girders

Girder s t i r rups shou ld extend 75 mm in to the deck and be hooked around alongi tudinal bar. The design er wi l l determ ine if Case A or B is need ed. If Case B isneeded for part of a structure, i t is to be used for the enti re structure, and the StandardSheet changed accordingly.

#13 cont, 2 per girder

450mm50mm cl*

Field bend as necessary

#13 cont, 2 per girder

*65 mm in Marine Environment

Case A

Normally used

Case B

Use where fillet will theoretically exceed 50 mm at center of girder.

The stirrup hooks will usually

be located as shown. Addtwo #13 bars per girderlocated in the hook.Do not show the stirruphooked around a top orbottom longitudinal bar, ofusual deck reinforcement.


5/5

14Prestressed

December 2004

Welded Wire Fabric in Decks

The use of welded wire fabr ic should be considered in detai l ing precast and precast-prestressed tees, channels, boxes, etc., where the deck reinforcement is relatively l ightand bend ing is min imal .

Precast Box Girders

75mm minhookembedment

Specify thisdimension asdetermined bydesign

#13 cont.4 per boxgirder

25 mm min, 100 mm max on low side. Allowance for constructiontolerance.Do not show the stirrup hook around a top or bottom bar of longitudinaldeck reinforcement.

De

pth@C

LBearing

bridge girder intermediate diaphragms_1

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