Can someone lead me to a site or reference to determine the torque capacity of a 2" thick (mild steel) 15" O.D plate with twelve 5/8" Dia bolts (grade 8)

My goal is to torque 14,000ft-lbs
I did a study on the shear of the bolts and it should take the load with good factor of safety.

Im just unsure of the plate failing (Too bad machine shop only has mild steel!!!)

Any help is much appreciated.

John