Effect of Increasing Ductility Factors on the Performance of a Steel Moment Resisting Frame Designed by the Performance Based Plastic Design Method attuned with Indian Code of Practice

Abstract

Effect of increasing ductility factors on the performance of a steel moment resisting frame has been studied. The frame has been designed for ductility factors 2,3,4,5 and 6 using the performance based plastic design method which is based on the “strong column–weak beam” principle. Pre-selected target drift and yield mechanism are chosen as performance criteria. The design base shear for selected hazard level is determined by equating the work needed to push the structure monotonically up to the target drift to the corresponding energy demand of an equivalent SDOF oscillator. Plastic design as per Indian Code of practice is performed to detail the frame members and connections in order to achieve the intended yield mechanism and behavior. It was observed that as the ductility factor increases, the lateral loads decrease and hence section becomes lighter leading to optimum strength utilization. No unexpected failure is observed in most of the frames and their performance under seismic loads satisfies the “strong column–weak beam” principle.