Column reinforcement in bundles (Do they have to be of same sizes?) 3

[ST04]

Dear colleagues

Recently I was encountered with a design of large column section. To make it simple, bars could be grouped in bundles and the code that I'm using is BS, it allows for bundles of 2,3 and max of 4 bars. But it doesn't state that each bundle has to be made of same bar sizes.

So is it possible to have for example a bundle of 2Y16+1Y25 or 2Y20+1Y12 and so on??

It might cause confusion during fabrication but it can save some money (there are enough columns to provide sufficient material savings)

Regards

 

[ishvaaag]

In Spain I think there wouldn't be any problem to such groups of bars, only meeting the specs for splice positions between groups an lengths of splice/embedment for the groups themselves.

 

[csd72]

I have not ever needed to use bundled bars myself but I believe that it is not a good idea to use dramatically different diameters.

The reason is, I believe, that the perimeter/cross sectional area ratios are different and can lead to quite different development of stress between the different diameters.

 

[msquared48]

Not only that, but, despite your best efforts, it WILL be screwed up in the field.

Use all the same size for simplicity. The extra capacity will not hurt either, assuming you can get adequate coverage.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask