Post Tensioning-Deferred Engineering/Detailing

[mrengineer]

Our firm is going to be involved in several condominium type structures, which have a good chance of being post-tensioned flat plate construction. I am wondering how far you typically take the engineering/detailing of such structures, as opposed to deferring same to the post-ten supplier. For example, for the banded tendons, do you typically show tendon direction, force after losses, and drape? Do you design/detail shear reinforcing in the slab? I don't want to be too far out of line either way compared to what the engineering community at large is doing.

 

[dik]

I've generally designed the slabs and when the supplier/contractor is selected, if there are any adjustments, then deal with them at that time... Alternatively, (and I haven't used this approach) you could spec a loading requirement and code to design to... and then confirm the design. This could be prone to extras to contract if there is something you are uncomfortable with and they have bid the project to spec...

Dik

 

[Loui1]

I'd recommend getting PTI's 2006 post tensioning manual. It describes exactly what the responsibilities of all parties are.

http://www.post-tensioning.org/

 

[AUCE98]

mrengineer,

I have worked for a PT supplier and I am currently work in a consulting firm. What you provide on the contract documents depends greatly on your geographic location. For example, for any permits to be pulled for construction in Florida, a building with pt floors need to have a "complete design" which many times means that the EOR has placed a large amount of PT on the drawings with minimum steel and sent it out the door, with the knowledge that the contractor will have the PT supplier re-design the slab more efficiently. Others will issue the drawings with the post-tensioning as a pre-engineered specification, as dik had indicated. Thirdly, you can design and detail the slab yourself indicating banded/uniform direction and force, drapes, mild-steel reinforcement etc. In this case all the supllier will do is provide tendon support drawings, tendon layout and endviews.

Regards,

AUCE98