Anchor Bolt and Base plate design 3

[IHcal]

Hi Folks

I have an industrial steel structure with fixed moment connection at base and have fair amount of moments in both directions. I am using 8 - 1 1/2'' anchor bolts. What is the right procedure to design anchor bolts and base plate when there are moments in both directions .. Any refernce material available..

Appreciate the response

 

[Einsteim]

Are the moments in both directions occuring at the same time? AISC Design Guide 1 has some good examples...don't think it addresses moments in both directions at the same time.

 

[WillisV]

For bi-axial moments, baseplates are generally either designed using a FE based method, or by determining an "equivalent eccentricity" in one direction and using typical uni-axial moment methods such as presented in AISC Design Guide 1.

One popular method of computing this "equivalent eccentricity" can be found in Section 11-8 of MacGregors Reinforced Concrete Mechanics and Design Book (this is from 3rd edition). The f'c and Ag used in this method are generally taken as the strength of the concrete in bearing and an assumed area of baseplate. I think STAAD used to do it this way.

I'm sure there are other strain based methods of checking it but I haven't seen a formal paper on them...