there should be a table somewhere (catalogues ? specs ??) where bolt strengths are given (for different sizes and materials).
try googling "types of bolts" and "strength of bolts".
be aware of the difference between single shear and double shear (which I think you'll have).
"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.