Collapse prevention seismic performance assessment of new special concentrically braced frames using ASCE 41

Abstract

This paper presents the results of a seismic performance assessment using ASCE 41-06 for six special concentrically braced frames (SCBFs) designed in accordance with the 2012 International Building Code. The correlation between ASCE 7-10 and ASCE 41-06 is investigated to compare the seismic performance anticipated by the two standards. Three archetype buildings (4-, 8-, and 16-story) with SCBFs along one principal direction are designed for seismic effects: (1) once using the equivalent lateral force (ELF) procedure and (2) a second time using the response spectrum analysis (RSA) procedure. Performance assessments are conducted using four analysis procedures, static and dynamic analyses performed under both linear and nonlinear analysis regimes. Linear analysis results indicate minor performance issues in the columns and no performance issues in the braces. In contrast, the nonlinear analysis results indicate that the braces consistently fail to meet the assessment criteria. The contributing factors to the noted performance issues with regards to ASCE 41 are investigated. Recommendations are made on how to alter the performance outcome such as using alternative ground motion selection approaches (e.g., conditional mean spectrum), using higher fidelity brace models, and having acceptance criteria based on cumulative ductility demand or energy dissipation.