ASCE/SEI 41 Predicted Performance of Newly Designed BRBFs
Matthew S. Speicher, John L. Harris
Structural engineers in the United States have turned to performance-based design methodologies for design of new buildings in order to find improved design solutions as compared to those obtained using prescriptive design provisions of current model building codes or standards, such as ASCE/SEI 7. Performance-based seismic design of existing buildings has been implemented in the U.S. for seismic retrofits during the past decade (e.g., ASCE/SEI 41). Engineers are now starting to rely more heavily on the existing building procedures in ASCE/SEI 41 for the design of new buildings in order to obtain satisfactory seismic performance in the most cost effective manner. However, a translation between the two approaches is not direct and can often be a challenge due to perceived conservatism in the ASCE/SEI 41 procedures and the somewhat different performance expectations between ASCE/SEI 7 and 41. This paper presents the results of a performance assessment of six buckling-restrained braced frames (BRBFs) to examine the correlation between ASCE/SEI 7 and ASCE 41. Two buildings are designed at each of the following heights: 4, 8, and 16 stories. The performance is then assessed using linear static, linear dynamic, nonlinear static, and nonlinear dynamic procedures for the buckling-restrained brace components. The linear and nonlinear results generally indicate acceptable performance, except for the 8-story frames, which gives insight into how ASCE/SEI 7 and ASCE/SEI 41 compare. Additionally, the linear results are not always more conservative than the nonlinear results, which is counterintuitive and is discussed in the context of the results.