Segmental Post-tensioned bridge design

[LordBerkley]

Sorry for this basic/vague question, but when designing a bridge made up of precast concrete segments that are held together by post tensioned tendons how exactly is the structure designed for shear? Specifically the shear between the faces of two adjoining segments. Do you design for the tension required in the cables to produce enough friction between the two faces so that they do not move/shear? Or am I totally wrong?

Any help very much appreciated!


LB

 

[MikeHalloran]

Segmented bridges as described were erected for I-75 in SoFla in considerable number.

They may be made differently elsewhere, but all the ones I've seen during erection had very substantial trapezoidal teeth at the interfaces. The joints were plastered over after the tendons were tightened, so you might not detect the teeth in a finished bridge.



Mike Halloran
Pembroke Pines, FL, USA

 

[a7x1984]

Link

Look at the image at the bottom of the page. You can see the very large trapezoidal key.

In Russia building design you!

 

[hokie66]

Agree with Mike and a7. The sections have keys. Whether they also rely on "shear friction", I don't know.

 

[LordBerkley]

Thanks guys you've put me on the right track!!