Inelastic analysis of semirigid frameworks

Abstract

This article presents an efficient method for inelastic analysis of semirigid planar steel frameworks. A compound element comprised of a plastic-hinge element and a semirigid connection element is located at member ends that may potentially undergo inelastic deformation. Nonlinear inelastic flexural behaviour is modeled by an empirical relation between moment and rotation for which the parameters are available from experimental results. A four-parameter model is employed to simulate the nonlinear moment-rotation behaviour of semirigid connections. The member stiffness matrix involving the compound element is expressed explicitly in terms of stiffness degradation factors that vary depending on the loading level. This permits direct account for the combined influence of inelastic and nonlinear connection behaviour on structure stiffness. A semirigid steel portal frame is analyzed to illustrate the proposed analysis method, and the results are compared with those obtained from experiments involving the same frame. © 2006 Springer.