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

Abstract

The present study offers a deductive linear design procedure based on optimally screened designs under nonlinear static procedure (NSP) of ASCE 41-17. A linearization algorithm is proposed for idealizing NSP pushover curves. The subsequent phase inferred a linear static methodology from the design philosophy underlying ASCE 41-17's NSP. The deduced design procedure is applied in providing a set of 6-story optimal 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, adjusted collapse margin ratio is evaluated for both design approaches using incremental dynamic analyses. The evaluation results, demonstrates that the deduced linear static design yields comparable outcomes with respect to NSP; without requiring complex inelastic analysis in design steps of ASCE 41-17. Using the code-based lateral load pattern, the linear static design resulted in a greater margin of safety against collapse in heavier designs with respect to applying the first-mode shape. The deduced design procedure yields an idea that supports a seismic design philosophy to prevent conflict between design and retrofit standards.