Steel percentage of reinforced concrete beam
Steel percentage of reinforced concrete beam
(OP)
Hi everyone!
I am designing a reinforced concrete beam where the required steel percentage is greater than the allowable max steel percentage.
The beam size has been predetermined by the architectural demand which carries a larger moment causing the steel required to go over max allowable steel. I remember my professor once said that if this case happens, then use the max allowable steel to compute for steel area to be furnished. The idea is to prevent over-designing in the member for this will cause unnoticeable or sudden collapse. But my doubt is that the beam may not be able to withstand the applied moment because the steel area required has been lower.
Any input and reference to help enlighten this issue.
I am designing a reinforced concrete beam where the required steel percentage is greater than the allowable max steel percentage.
The beam size has been predetermined by the architectural demand which carries a larger moment causing the steel required to go over max allowable steel. I remember my professor once said that if this case happens, then use the max allowable steel to compute for steel area to be furnished. The idea is to prevent over-designing in the member for this will cause unnoticeable or sudden collapse. But my doubt is that the beam may not be able to withstand the applied moment because the steel area required has been lower.
Any input and reference to help enlighten this issue.






RE: Steel percentage of reinforced concrete beam
Too much steel is not good for the reason you described. Too little steel is not good because the strength is too low. So that leaves making the beam larger. You can't always satisfy architects.
RE: Steel percentage of reinforced concrete beam
You probably do need a larger beam and I imagine that your deflection estimates will bear that out. Are you making use of T-beam action? That can help.
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.
RE: Steel percentage of reinforced concrete beam
RE: Steel percentage of reinforced concrete beam
RE: Steel percentage of reinforced concrete beam
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RE: Steel percentage of reinforced concrete beam
Based on your respective experience, which rho value would you like to use to compute for As1?
T-beam is another option to overcome this issue, but personally I am not really convinced to accept the reality that T-beam is safe in the long run for moment resisting frame of a bldg, instead I prefer doubly reinforced rectangular section.
RE: Steel percentage of reinforced concrete beam
long term deflection.
clear spacing between bars.
congestion of reinforcement at column
better to have a look on possibility of making the beam wider
RE: Steel percentage of reinforced concrete beam