Post tensioned slab ramps

[keenaseng]

I am looking at a split level post tensioned carpark that has transitional ramps between levels, and I was wondering how the ramps are built. Ramps are 20% grade with 10% transitions top and bottom. Ramp span are about 8.5m. Was thinking of Corbel joint at base of ramp to lower level.

I was thinking drape the PT cables down from the upper level and stress from the top down? Are there issues with the ramp wanting to lift up as a result of stressing (ie. cable straightening) if I have a just a corbel joint (not doweled) at the base of the ramp?

Am I better of considering a RC ramp instead? 8.5m span seems bit large for RC - would probably need a mis span support.

 

[rapt]

Keenaseng,

Draw all (and I mean ALL, not just the uplift from the parabolic profile) of the forces that are imparted by the prestress and then you will be able to see what is happening.

 

[dik]

Can be a bit of a problem due to the geometry and often the short lengths involved. They also are subject to the most wear and tear...

Dik

 

[dik]

Should have added that I usually use regular reinforcing for these items.

Dik

 

[rscassar]

These are from lecture notes.

 

[hokie66]

kikflip,
What did you learn from the picture? It illustrates the complete lack of knowledge of several things, but is not pertinent to the OP's question.

 

[dik]

interesting pix, though...

Dik