Settlement and bars yielding

[laurg]

Concrete columns can suffer settlement.. can this cause some bars to yield? for example rebar strain is about 0.002 and there is bound to be settlement in some parts due to the reinforcements and stirrups.. this can cause gap of 0.005 that is already in yield strain of rebars.

 

[KootK]

Do you mean creep rather than settlement? If so, then it is true that as concrete columns creep a lot of the load gets transferred to the rebar in a manner that is not explicitly accounted for in routine design. It's one of the reason for the 1% minimum reinforcing rule I believe.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[laurg]

when there is a lot of stirrups sometimes settlement occurs such that there is a 1mm gap. This can cause the bar to hav a strain of say 0.005. What would happen if some bars are in yield strain but much below the rupture strain. Is it not they still function well?

 

[laurg]

oh i take it the strain of bars under tension and compression is similar in value? but whereas in tension it is stretched.. in compression, it is being compressed.. so could strain reAlly be similar?

 

[hokie66]

I think laurg may be referring to plastic settlement cracking, which can occur in vertical elements if the concrete is not well consolidated. The main consequence of this poor construction practice is potential corrosion of the steel, resulting in spalling of the concrete cover.

 

[laurg]

Thank you all for the help.