Calculation Method of High Temperature Bearing Capacity of Steel Columns Considering Creep Effect

Abstract

High temperature creep has a great influence on the internal force and deformation of steel structures under fire. The current "technical code for fire prevention of steel structures" (GB 51249-2017) does not consider the influence of creep on the high temperature bearing capacity of steel columns. ANSYS software is used to analyze and consider the mechanical properties of the steel column under high temperature after creep, and compared with the fire resistance test of the steel column, it is found that the finite element simulation results of the steel column considering creep are in better agreement with the test data. Through parametric analysis using the verified finite element model, the results show that after considering creep effect, the high temperature load bearing capacity of the steel column is greatly influenced by initial defects (residual stress, initial bending, initial eccentricity), bending direction, load-to-load ratio, length-to-fine ratio, and temperature rise rate, and is less influenced by section form and steel yield strength. A simplified method for calculating the high temperature bearing capacity of steel columns considering creep effect is given.