Moment due to Tension on Anchor bolts 1

[jmurph36]

I have been reading through AISC design guide 1 and I came to appendix B to the design example of a base plate with large moment. I have been staring at the equation for the bending moment in the plate per unit width of plate for hours trying to understand how it is derived. I don't understand why they take the m value subtract out the edge distance of the bolt then divide it by 2 times that distance. I would really appreciate anyone who could give me clarification on this. Thanks.

 

[Ingenuity]

I think this is what you refer:

Assumes 45° load spread from C/L anchor rod to critical section (which is 0.95d).

 

[jmurph36]

That's exactly what I'm referring to. Thanks so much for the help. I racked my brain trying to figure that problem out.