Seismic performance of steel moment resisting frames retrofitted with a locally reduced beam section connection

The seismic behaviour of steel moment resisting frames retrofitted with a locally reduced beam section (RBS) connection is investigated. Reducing the width of beam flanges away from column faces has been proposed to eliminate the potential for brittle fractures of welded beam-column connections in existing and new moment resisting steel framed buildings. A half-scale, two-storey, RBS moment resisting frame model was subjected to historical ground motions on the earthquake simulation facility of Ecole Polytechnique in Montreal. The design criteria of the RBS joint configuration used in the model are described. Nonlinear finite element analyses were performed to predict the plastic rotation capability of the RBS joint. The experimental results obtained from the shake table tests are compared with the results generated from an inelastic time-history dynamic analysis. The RBS connection performed well during the tests. Stable and ductile behaviour was exhibited by the specimens. It was also shown that the behaviour of RBS connections can be accurately predicted by nonlinear finite element and inelastic time-history dynamic analyses.