Anchor bolt design / "effective bearing length" meaning & calculat 1

[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!

 

[ludvik]

I think the bearing length they are refering to is the length of bolt that is bearing against the concrete/masonry for use in a bearing stress calculation. That is to say, the whole length of the bolt does not act to resist transverse/shear forces, only the top portion.

I have never seen your formula before, but it looks like some kind of expression of static equilibrium somehow combining the moment, shear, and pullout forces into one incomprehensible formula.