shear Force distribution on more than 2 columns of bolts

[TLycan]

dear All,

I want to know if the shear force is distributed equally on the bolt columns . That is each column takes an equal share of the shear force . that is P/6 as per attached drawung
and if there is any specs that states so.

Regards

 

[KootK]

The load distribution would not be uniform within the elastic range. I'd expect the inner columns to pick up more load. If the failure mode of the bolts is ductile, as it often is for steel to steel connection, then load can redistribute to the more lightly loaded bolts after the inner bolts start to give way. This allows designers to assume an even bolt load distribution, within reason. It depends, in part, on what you're attaching to and the proportions of your connection plate.

I don't know of a spec that addresses this explicitly. I think there's something for tension connections that modifies the capacity of very long bolt groups to account for the fact that the bolts farthest from the point of load application will be the most lightly loaded.

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.

 

[clarke1973]

Is that an actual connection you are detailing or is it just a theoretical question you want answering?
It is a very impractical detail, there's no way you should need that amount of bolts for simple end plate connection in shear.

 

[TLycan]

This is very close to reality but it's in rc beam. I have 4 columns and 3 rows and I am using the hilti design program. but I am sure that the program algorithm doesn't consider this situation. It only assumes that that load is distributed equally on the columns

 

[KootK]

Given the proportions of your plate, I think that a uniform load distribution is reasonable. I'd consider using welded washer plates if your bolt holes will be oversized. That may help alleviate the problem where some bolts engage before others due to the random positioning of the bolts within the holes.

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.

 

[ooox]

Hilti has a washer system that allows you to assume all bolts are uniformly loaded in shear - Link