Inelastic Limit States Design Part II: Three‐Dimensional Frame Study

Abstract

A design study of a three‐dimensional 22‐story frame is presented to demonstrate the use of second‐order inelastic analysis in load and resistance factor design. This study is a follow‐up to a set of low‐rise planar frame studies presented in a companion paper. The limit state behavior of the inelastic design is evaluated with respect to strength and serviceability requirements. The strength requirements include investigating the inelastic rotation demands, effects of residual stresses, and conformance with a limit states design specification. The inelastic design is also compared to a design obtained using conventional elastic methods of analysis. The study indicates that with computer‐aided engineering, second‐order inelastic analysis provides a feasible alternative for designing steel structures of substantial size. It also concludes that existing limitations of current analytical techniques, e.g., the inability to model torsional‐flexural instabilities of beam‐columns, need to be overcome before inelastic analysis‐design approaches such as that presented can be generally applied.