ETABs not using beam rebar overwrites?

[ilyas415]

Hi all,

I'm quite new to ETABs and still a young inexperienced structural engineer, so apologies in advance!

In ETABs, I have decided the reinforcement I would like to use in my beams and specified the end reinforcement overwrites for my beam sections. For example:

However, when I run the concrete frame design check, it seems like ETABs is using its own (lower) values of reinforcement for the section. See image below:

Actually, I thought the rebar should be matching what I specified? Especially since the values I specified are higher than what ETABs is deciding to use?

Thanks in advance for your help!

 

[jayrod12]

I could be wrong, but Etabs is showing the rebar required to work by it's analysis. If you're providing more then that's ok to a point, just make sure that whatever you're providing still results in a ductile beam.

Side note: There may be more stuff to keep an eye on when it comes to seismic, but I don't design in a seismic area so I'm relatively clueless in that regard except to know that it could require special attention.

 

[ilyas415]

Thanks a lot Jayrod.

As you said, it is in a seismic area. My understanding of seismic design is that I need to make sure my plastic hinges develop in my beams first, rather than my columns. So one of the key results to look at is the Column-Beam Capacity Ratios.

I just want to make sure that the beam capacities are being calculated based on the reinforcement I specified? Or the required reinforcement being proposed by ETABs to make it work? Do you know?

Thanks again.