Steel moment resisting frames with both joint and beam dissipation zones

Abstract

Normally, the design of steel moment resisting frames in seismic areas encourages the formation of plastic zones in the beams. This paper investigates numerically the performance of moment resisting frames designed to dissipate hysteretic energy in joints and beams together. Joints can be a stable source of hysteresis, provided they are designed with ductility requirements. The commonly used bolted end-plate connection is adopted here. In order to provide spacing between the expected plastic zones in the connection and the beam, a reinforcement scheme with cover plates is employed. Appropriate methodologies are provided for the design of connections and cover plates. The proposed joint and beam dissipative frames are evaluated through parametric push-over and time-history analyses. Comparison is performed with frames designed with rigid joints that dissipate energy mainly in beams. The results show that the proposed frames not only don’t suffer in terms of drifts or capacity, due to the added joint flexibility but they provide superior performance in many aspects, while they can offer economical advantages, due to their reduced bending moment requirements.