Simple Shear Tab Connections to Column Webs
Simple Shear Tab Connections to Column Webs
(OP)
Hello,
I'm currently designing some simple shear tab connections into column webs, which I believe are pretty common. We are using shear tabs that extend beyond the flanges of the column, so that large beams can attach without copes or erection issues. We are providing welded stiffeners at the top and bottom of the tabs within the column flanges. These shear tabs have a single row of bolts (see picture attached for clarification).
Do we need to account for bolt-group eccentricity on the single row of bolts, if the distance from the face of the column flanges/stiffeners to the bolt row is only 3"? It seems that standard practice is to NOT account for an eccentricity, unless the bolt row is more than 3-1/2" from the stiffeners, but I've found some conflicting information about this scenario and the AISC manual is not clear. RAMConnection does not account for any bolt group eccentricity when we model this type of connection in the program with the bolt row located 3" from the stiffeners.
Hopefully this is a pretty basic question for any of you connection designers out there. Thanks for your help!
I'm currently designing some simple shear tab connections into column webs, which I believe are pretty common. We are using shear tabs that extend beyond the flanges of the column, so that large beams can attach without copes or erection issues. We are providing welded stiffeners at the top and bottom of the tabs within the column flanges. These shear tabs have a single row of bolts (see picture attached for clarification).
Do we need to account for bolt-group eccentricity on the single row of bolts, if the distance from the face of the column flanges/stiffeners to the bolt row is only 3"? It seems that standard practice is to NOT account for an eccentricity, unless the bolt row is more than 3-1/2" from the stiffeners, but I've found some conflicting information about this scenario and the AISC manual is not clear. RAMConnection does not account for any bolt group eccentricity when we model this type of connection in the program with the bolt row located 3" from the stiffeners.
Hopefully this is a pretty basic question for any of you connection designers out there. Thanks for your help!





RE: Simple Shear Tab Connections to Column Webs
RE: Simple Shear Tab Connections to Column Webs
However, you might look at Tamboli's Handbook of Structural Steel Connection Design and Details. I'm looking at the first edition figure 2.49 and it implies the full distance. Though that is for a skewed connection. Then it references Kloiber and Thornton's: "Design approaches to to shear connections for skewed Members in Steel Structures" published by ASCE in the 1997 Proceedings of Structures Congress
RE: Simple Shear Tab Connections to Column Webs
If the distance from the bolt centerline to the connection to the column is 3.5" and the number of bolts is equal to or less than 9 the AISC says you can ignore the eccentricity. For other cases they say to size the bolt group accordingly to resolve the eccentricity. Alternatively, they say that the eccentricity can be taken out by other means. They reference research from Sherman and Ghorbanpoor.
RE: Simple Shear Tab Connections to Column Webs
I've seen connection designs from steel detailers that obviously don't account for an eccentricity (assuming that the stiffeners designate the "connection to column" and therefore allow the shear tab and bolts to be designed as "conventional"), and I've had discussions with other engineers who argue that the stiffeners don't matter and an eccentricity has to be considered all the way back to the column web (and thereby forcing an "extended" shear tab design with an eccentric bolt group).
RE: Simple Shear Tab Connections to Column Webs
RE: Simple Shear Tab Connections to Column Webs
RE: Simple Shear Tab Connections to Column Webs
@structSU10 - After doing some additional research, this is the conclusion I've reached. This question was asked in the March 2012 issue of Modern Steel Construction, and the answer was the same as yours (see attached). If you account for the additional moment in the design of your columns and design the stiffeners for the moment forces, then, yes, you can reduce the eccentricity on the bolt group.