Indian Journal of Science and Technology

Abstract

This study focuses on the development of seismic design of steel moment frames using Performance Based Plastic Design (PBPD) method. This methodology implements the energy–work balance equation to calculate the design base shear. Also the preselected target drifts and yield mechanism are considered since the start of the procedure. By considering gravity load and p-delta effect, the PBPD method was initially developed for steel frames with different bays. Then for better efficiency of PBPD method, some equations are presented in order to estimate the required moment of columns. A somewhat accurate estimation, helps preventing yielding in columns during sever ground motion that leads to undesirable yield mechanism in the structures. For validating this methodology, two 5 and 10 story frames are designed as case studies in both PBPD and elastic design method which have been evaluated under numerous nonlinear static pushover and dynamic analysis. The results indicate that the PBPD frames perform according to expectations in case of yield mechanism and target drift levels whereas the ED frames suffer large story drifts due to flexural yielding of the columns. Since PBPD method is a direct design method, little or no evaluation are needed after the initial design because the nonlinear behavior is built into the design process from the start.

Keywords: Energy Spectrum Method, Performance Based Plastic Design, P-∆ Effect, Seismic Demand