Column Beam Brace Connection - Eccentricity in axial force

[N G P]

Greetings.

As shown in the attached figure, I have been checking a column beam brace connection. In my case, the brace member is a TEE section made from UB sections. The line of action of the axial force in the brace member is acting along the centroid of the TEE section which is at a distance away from the gusset plate line. The same is applicable to the angle and channel braces.

When I tried to check in Idea Statica, it seems that the eccentricity is taken into consideration and a bending moment is developed in the gusset plate and bolt group. Eventually, the plate, bolts and welds are failed. And Idea Statica verifies the plates by the FEM method.

However, in RAM Connection and other typical connection design methods, this eccentricity and the resulting moment are not taken into consideration.

My question is whether it is important to consider this bending moment due to the eccentricity or can we assume that some redistribution may happen in the brace sections and thereby it mitigate the eccentricity.?

 

[KootK]

In many situations, it is thought that the bracing member deals with the lion's share of the eccentricity induced moment by virtue of it's being the stiffest place for that to go. There was an excellent thread on this back in June which included some top notch work by member Deker: Link.

 

[JoshPlumSE]

There was a good article (in Modern Steel Construction) by Bo Dowswell, some years ago. It's really meant to address horizontal bracing connections and the type of eccentricity (from Tee braces) that you talk about. I found this article to be very informative.

I believe this is the link (from July of 2010):

https://www.aisc.org/globalassets/modern-steel/steelwise/072010_july10_steelwise_web.pdf

 

[N G P]

Thank you gentlemen for pointing to the very right place where it is discussed in detail.