Can we cut a Post tensioned deck 3

[CROWN06]

We have a post tensioned deck bridge. The tendons are in both directions (like two way slab). Can we cut bridge in half for stage construction?

 

[COEngineeer]

I am still confused what your question is but it doesnt sound good.

 

[WillisV]

I am sure you can cut the bridge in half. Whether it will actually remain standing after you do this is the more pressing question...

 

[Ingenuity]

Post-tensioned bridge decks are constructed with BONDED(grouted) tendons, so the cutting and demolition of such elements are not a big deal - assuming the grouting was good etc. If for some reason the tendons are UNbonded (usually only used in building structures in the USA and other markets)), then you need to take a few additional precautions before severing the strands.

 

[dik]

willisv... hehehehehe

Is this part of demolition to reconstruct the bridge? If so, you likely have to provide temporary shoring to support it as you cut the existing strand. As willisv pointed out, there is a lot of stored energy in the cables and they can be dangerous. I recall hearing about 40 years ago that a local worker was cut in half by a broken strand (dunno if this is an urban legend or not). You might begin by locating the strand initially.

Dik

 

[csd72]

CROWN06

Is it demolition or new build? We can only have a stab in the dark if we dont understand the situation!

 

[CROWN06]

It is demolition. But we want to do it in two stages, so that traffic keeps using at least half bridge. The bridge is not old, It was build in 1993. We need to extend the horizontal clearance of the bridge. So we are planning to demolish existing in two stages and build new simultaneously in two stages.

 

[JAE]

Can you get assistance from the state DOT on that bridge? I would highly recommend that you get someone to look at it. If its fully bonded, that helps, but plese don't make a decision on this based upon Eng-Tips responses. This really calls for an engineer to review the design and perhaps even analyze it for the proposed demo stages.

 

[swmiami]

I inherited a project in which a 20ftx37ft post-tensioned slab shall be removed to create an opening. We hired a specialist and he contacted contractors. They will use "ground penetration radar" to locate tendons and use "impact echo scanner" to detect voids. If a conduit was not solidly grouted, a small area will be opened and the conduit will be regrouted. The construction has not started yet.

 

[PHDPE]

The dead load of the prestress girder is balancing the pulled strands. That's why while transporting if Girders are rotated, they explode. When we cut the bridge we might be changing this equilibrium also.