Anchor bolt design / "effective bearing length" meaning & calculat

[dannyo]

I am trying to verify some equations relating to the design of anchor bolts on the saddle of a horizontal vessel in a seismic / wind load design situation.

My understanding is that anchor bolt design is governed by one of three load cases including: longitudinal load, shear load, and transverse load.

Assuming these are correct, my question lies in the transverse load case. The book I'm using has a 6 step method of analyzing the transverse load on the anchor bolts. I have not been able to verify the author's design method or any of the equations he uses.

If anyone could inform me the origin of the following equation and any references I could find additional information, I would greatly appreciate it.

I am mainly confused about what is called the "bearing length" (Y) It is calculated by solving the following equation for Y:

Y^3 + K1*Y^2 + K2*Y + K3 = 0

where Y has units of (inches / cm / etc...) and K1, K2, K3 are all factors relating mainly to the moment force produced by the seismic / wind event.

If my question is unclear, please respond and I will try to provide any additional information.

Thanks a million in advance!

 

[Imagineer]

Where did you get this equation? In general, the best anchor bolt/base plate reference is "Design Guide Series 1:Column Base Plates" from AISC (Amer. Inst. of Steel Construction). You can buy it from there website for about US$20.

Imagineer