A deductive design method to simplify ASCE 41-17 nonlinear static procedure preserving the adjusted collapse margin ratio of steel moment frames

Abstract

The present study offers a deductive design procedure based on designs that have been optimally screened in accordance with ASCE 41-17's nonlinear static procedure (NSP). The subsequent phase inferred a linear static methodology from the design philosophy underlying the NSP of ASCE 41-17. The deduced design procedure is applied to provide a set of optimal 6-story SMRF designs under two load patterns: the code-based and the first-mode shape patterns. The optimal designs by the proposed deduced linear procedure are compared with those optimized under ASCE 41-17's NSP using FEMA p695 metrics. Consequently, the adjusted collapse margin ratio is evaluated for both design approaches using incremental dynamic analyses. A linearization algorithm is suggested for idealizing pushover curves. The evaluation results demonstrate that the deduced linear static design produces designs that are comparable to those of the ASCE 41-17's NSP without necessitating a sophisticated inelastic analysis. Using the code-based lateral load pattern, the linear static design resulted in a greater margin of safety against collapse and heavier designs with respect to applying the first-mode shape load pattern. The deduced design procedure yields an idea that supports a seismic design philosophy to prevent conflict between design and retrofit standards.