The plasticity algorithm refers to the emergence of plastic hinges in a hyperstatic structure by reaching the yield strength at the expected site, thus achieving the redistribution of plastic internal forces, and it must be ensured that the structure does not form a variable or transient system.Consideration of post-buckling strength refers to the loss of local stability of the web of the bent member still has a certain bearing capacity, and make full use of its post-buckling strength of a member calculation method.