Enhancing Seismic Performance of Semi-rigid Connection Using Shape Memory Alloy Bolts Considering Nonlinear Soil–Structure Interaction

Abstract

Steel Moment-Resisting Frames (SMRFs) have their lateral resistance for their rigid connections, while real conditions have shown that the rigidity of a connection depends on the bolts and the end-plate thickness, which may not provide the assumed rigidity in design process. In this research, the main goal is to enhance the semi-rigid connections using shape memory alloy (SMA) bolts and explore their effects on the seismic limit-state capacities of the 3-Story, 5-Story, and 7-Story SMRFs considering the effects of nonlinear Soil–Structure Interaction (SSI). To model the 3-Story, 5-Story, and 7-Story SMRFs, ETABS software was used; then, 2D models were developed in Opensees and the SSI effects were added using Beam on Nonlinear Winkler Foundation (BNWF) model. To achieve the seismic limit-state capacities of SMRFs, Incremental Dynamic Analysis (IDA) was performed and three rigidities of 80%, 70%, and 60% were considered. In each model, the SMA bolts were used to find out the improvements of semi-rigid connections. The results showed that assuming different rigidities as well as the SSI effects could reduce the performance levels. In addition, the results confirmed that SMA bolts could increase the seismic limit-state capacities of SMRFs and this approach can be used for retrofitting of existing buildings.