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Wider beam on supported column

Wider beam on supported column

Wider beam on supported column

I want to ask about the limit allowed for cases when the reinforced beam width is larger than column width. Is it correct to be wider and what is the percent to be wider? On other hand what is the negative reinforcement percent that developed in this case ?

RE: Wider beam on supported column

A wider beam on a column generally makes it easier to reinforce; there is less conflict with reinforcing steel. I'm not aware of any limits, but, have used 'slab bands' where the width is several times the width of a column.


RE: Wider beam on supported column

Design and detail the beam so that the beam reaction occurring in the portion of the beam overhanging the column actually gets into the column.

RE: Wider beam on supported column

1) Beams can be wider than columns without limit.

2) In some seismic applications, one must observe "strong column / weak beam" requirements.

3) The primary issue at the connection is the transfer of shear and moment between wider beams and narrower columns. Depending on beam width, behaviour starts to resemble that of column/slab joints with similarities to punching shear, moment leakage etc. Similar to MC's point.

4) ACI publishes as standard on monolithic beam-column joint that may worth your time parodying.

5) End column connections are particularly challenging and it may not be appropriate to utilize all of the negative reinforcement placed outside of the column.

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: Wider beam on supported column

The paper "One-way Shear in Wide Concrete Beams with Narrow Supports" by Lubell, Bentz and Collins presents a shear reduction factor of
Beta=0.7+0.3bc/bb (I've changed notation slightly)
bc = column width
bb = beam width
They tested bc/bb ratios of about 0.25
This reduction factor applied to Vc+Vs

These tests also suggest wide stirrup spacing is not a good idea (many other tests have shown this aswell). I personally keep required stirrup legs within column width.

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