Rebar choice of concrete column and beam 1

[dr. rifat]

Hello engineers,
Is there any problem if we choose larger bar diameter in beam and smaller bar diameter in column?Please experts ansewer with detail.

RIFAT

 

[KootK]

I see no technical problem with it. One would need considerably more information in order to assess the practical aspects. Some things that go into consideration:

1) Sometimes you want bars light enough that a single person can move them around.
2) Fewer large bars are often more economical than more smaller bars from a material economics standpoint alone (less column ties etc).
3) Sometimes your bar choice can affect the effectiveness of your flexural depth.
4) More smaller bars can be better for crack control.
5) One should study whether or not beam bars can pass through and around column bars where required.
6) Large bars have long splice lengths.
....

Perhaps you have specific concern that we can address?

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.

 

[dik]

No reason at all... check to see that the vertical and horizontal bars fit.

Dik

 

[KootK]

Are you perhaps concerned for strong column / weak beam seismic issues?

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.

 

[dr. rifat]

Are you perhaps concerned for strong column / weak beam seismic issues?

Yes

RIFAT

 

[KootK]

Gotcha. Then keep in mind that flexural capacity is a function of total reinforcing bar area, not individual bar size. It's possible to have a strong column with lots of small bars and a weak beam with relatively few large bars.

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.

 

[dik]

Try to make the beam wider than the column so that the column reinforcing passes between the beam reinforcing and you don't end up with a 'dust' surface at the top of the column.

Dik