Finite element procedures development for nonlinear steel frame analysis with quasi-static semi-rigid connection

Abstract

As the semi-rigid behaviour becomes essential in current design consideration, this paper presents a study on the development of a nonlinear numerical analysis that is capable of simulating the quasi-static semi-rigid behaviour of structural steel frames under variable loadings for reliable design. The beam element shape functions with semi-rigid connections are formulated and the overall stiffness matrix is derived. The theory to solve the nonlinear analysis is also presented. The developed procedures also revealed the complex finite element calculations in order to identify the structural performance of nonlinearity for steel structures. The major modifications that include the revised solution procedure, the variable load pattern capability, the quasi-static connection model, the modification of input data to cater for initial imperfections and the inelastic constitutive model for steel are presented. Validation process has been performed for the developed finite element procedures with loading and unloading behaviour for semi-rigid connections and full-scale frame behaviour. From the results, the modified procedures are capable to predict the behaviour of the structural steel frames under varying loading conditions with various connections configuration and material properties.