HSS Column encased in concrete at the base...

[KevinChez]

I am reviewing a detail as an Owners rep that shows structural HSS posts supporting a roof canopy that is encased in concrete 3' above grade and 2' below grade to the footing. I am not concerned with supporting loads but with concrete cracking due to expansion and contraction from temperature & concrete shrinkage. I don't want the concrete to crack.

A quick internet search did not get me anywhere. But I will keep researching.

If you can point me in any direction...thanks!!

 

[CANPRO]

How thick is the concrete around the HSS? If it’s thick enough cover maybe you could get some mesh or rebar in there. If it’s not thick enough to get some reinforcing in there, I’d be concerned about the cracking as well.

 

[JAE]

Thermal coeff. for steel and concrete are about the same - so differential movements from temperature shouldn't typically be an issue.

Concrete wrapping around steel tubes can crack due to natural shrinkage at the four re-entrant corners - so carefully placed ties and vertical bars are a must to keep cracks as tight as possible.
I like to keep the minimum concrete thickness at 4-6 inches.

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[KevinChez]

Thank you...I just viewed the structural detail and the HSS has 5/8" diameter studs at 16" o.c. on each face. And there is at least 7" of cover all around. Pier is reinforced with ties.

Architectural details showed very little.