Evaluation of sensitivity of CBFs for types of bracing and story numbers

Abstract. Recently, there have been many studies about ductility reduction factor of CBFs, because AISC's seismic design provision has been changed signicantly since 2010. Therefore, a comprehensive study is needed for seismic designing and ductility reduction factor of CBFs. In this study, about 160 two-dimensional CBFs with dierent types of bracing are designed according to AISC-341, and ductility reduction factor of designed frames is compared to types and formation of bracings in the height of frames. The results conrm that ductility reduction factor and response modication factor of CBFs are mostly dependent on types and formation of bracing. Also, maximum allowable height of OCBFs can be reduced for some types of bracing and be increased for some other types of bracings. For SCBFs, ductility reduction factor depends on the bracing type and number of frame stories. For most of SCBFs, ductility reduction factor cannot achieve more than ten-story frames. So, for these kinds of frames, maximum allowable height should be decreased, or smaller response modication factor should be used. For double large-scale CBFs, because of the enormous stiness of one-to-seven-story frames, ductility reduction factor cannot be obtained and a smaller response modication factor should be used.