U-bolt Calculations

I have a slightly confusing, yet seemingly simple, problem at hand.

A metal pole is secured to another pole that is anchored into the ground by a U-bolt.

I can have two load cases: one where the pole is being pulled away (i.e. tension load on both ends of u-bolt); other the pole is being pushed to the side (i.e. shear load on both ends of the u-bolt).

Firstly, what are failure modes of the u-bolt?

How would I calculate the required size of the u-bolt (or capacity of, given a size)?

What would the standard for u-bolts (i.e. where would I find tensile/shear capacities of, say M12 u-bolt)?

Thanks