Elastic plastic analysis of semi-rigid industrial frames

Abstract

The behavior of steel frames is highly influenced by the beam-column connections. In analysis and design, they are idealized as either rigid or pinned for simplicity and between these two extremities lie the actual behavior of steel frames connections which is semi-rigid. This classification is characterized by the nonlinear moment-rotation relationship which must be incorporated in the analysis. Cap-plate connection is widely used in industrial steel frames for its advantages over other types of building connections, but the response of such connection has not been theoretically and experimentally determined. In this research, the behavior of cap-plate connections was studied by testing six different connections to obtain data for moment-rotation curves of such connections, to measure the forces in the tension bolts, and to measure the strain distribution at different cross-section along the beam at the connection. A computer program was developed for a refined analysis of industrial steel frames taking into consideration the nonlinearities resulting from the connection flexibility and second-order effects. A mathematical model for the connection moment-rotation curve is also proposed using the finite element method and the yield line method. A good agreement was found by comparing the proposed model results to the experimental results