I can't figure out how SERM problem 8-2 or 8-5 determined load factor to calculate bending moment and shear at bridge support. In problem 8-2 gamma (load factor) is calculated as 0.083, 0.09, 0.0064 and 0.0051 for the concentrated loads (4ea 32kips). Could someone help me how these load factors are calculated or any tabulated factors.