THE COLLAPSE MECHANISM AND DESIGN CRITERION OF BOX-SECTION STEEL COLUMNS AND BEAM-COLUMNS UNDER CYCLIC LOADING

摘要

A finite element formulation for steel members under cyclic loading was performed by the author, which is based on degenerated shell element with updated Lagrange method and on mixed hardening law. The applicability of the program was firstly verified, and then a thorough analysis was carried out on box section steel columns under uniaxial cyclic loading to evaluate their stiffness and bearing capacity, the relationship between structural strength and the slenderness of plate elements, and the limiting width-to-thickness ratio of flanges. Finally, a parametric analysis on box-section beam-columns subjected to cyclic bending was performed to evaluate the major influencing factors, the requirement to be satisfied in seismic design of these factors, and the interrelation of axial force and moment.