. 取梁BC段为受力平衡对象:
. ΣMB =0, Rcy.2m -(100KN).1m =0,
. 得:支座C的约束反力Rcy =50KN, ( ↑ ) ,
. 取整条梁为受力平衡对象:
. ΣFy =0, RAy -(20KN/m).4m -100KN +50KN =0,
. 得:支座A的约束反力RAy=130KN, ( ↑ ) ,
. ΣFx =0, RAx =0,
. ΣMA =0, M -[(20KN/m).4m].2m -(100KN).5m +50KN.6m =0,
得:端支座A的约束反力偶矩 = 360KN.m, (逆时针绕向) ,