Concrete deck expansion joint

[structuralnerd]

I'm designing a 2 level concrete parking deck - post-tensioned beams with a cast-in-place slab spanning between. It is approximately 280 feet long by 180 feet wide. Do you recommend I put an expansion joint in?

 

[spats]

NO, the building is not big enough. However, you need to design parking garages for the expected thermal stresses, based on the design temperature range for the locality of the project. Any general analysis program can be used to analyze thermal strsses, and the codes give you the required load combinations.

 

[OzEng80]

I believe 280x180 warrants an expansion joint. Consideration is obviously required as to the degree of restraint offered by your column/wall system, but the opportunity to achieve almost square slab panels is pretty hard to go past.

If you stay with the 280x180 single pour, ensure that your corner columns can take the shrinkage movement without exceeding the column cracking moment.

Cheers

 

[hokie66]

Shrinkage of the concrete will almost certainly exceed any expansion you may have from temperature, so I think expansion is the wrong word for any joints you may use. As OzEng80 says, restraint is the main issue, and a temporary or permanent movement joint could assist in reducing restraint forces.