Calculate moment of interia of vertical bolt group?

[StructureMan44]

How can the moment of inertia (Ix) of a vertical group of 3 bolts be calculated? I'm attempting to use the elastic method to determine if a bolted connection will be acceptable for an eccentric shear load.

 

[jreit]

14th edition AISC Manual Part 7 explains the elastic force method.
A search shows the link:

http://www.bgstructuralengineering.com/BGSCM14/BGSCM004/BGSCM00403.htm

 

[Trenno]

A sketch is always helpful.

But firstly you need to find the centroid of the bolt group (which sounds like it is the middle bolt), then take the second moment of area of the bolts about this centroid to find Ix and Iy.

Then using Ix and Iy, calculate Ip, which from there you can find a resultant shear force using Vx, Vy, Mix and Miy (caused from the eccentric shear load).

 

[Lion06]

No different for a bolt group than for any other area. Summation Ad^2 about the centroid of the bolt group.