Nonlinear analysis of three-dimensional steel frames with semi-rigid connections

Abstract With the ultimate aim of improved methods for the realistic limit state design of structures, a method has been developed for incorporating nonlinear connection response in the analysis of three-dimensional steel structures. The method is implemented in an interactive graphics analysis and design program which can model both geometric and material nonlinearities in framed structures. The connection model includes nonlinear moment-rotation response for both major- and minor-axis bending. Standardized models for different types of connections which are calibrated to existing test data and are amenable to design are presented. Application of the method is presented for a realistic case study consisting of a low-rise three-dimensional structure with partially restrained connections.