LAUSR

Abstract Steel moment resisting frames are prevalent seismic force resisting systems that are used extensively in high seismic regions worldwide. New design procedures suggested by codes have resulted in extensive use of semi-rigid connections in moment resisting frames. These connections have some degree of flexibility. This study focuses on seismic performance of steel moment-resisting frames with different degrees of moment connection rigidities. Three moment frames (5, 10 and 15 stories), each with different levels of connection rigidities (full, 80%, 70% and 60% rigidities) are analyzed under the 22 far-field ground motions presented in FEMA P695. Detailed modal analysis, non-linear static (pushover) analysis and incremental dynamic analysis (IDA) were conducted. Results reveal that semi-rigid frames have lower base shears and higher structural deformations, but higher energy absorption capability. Lastly, detailed performance analysis was conducted. The results show that probability of exceeding the fully operational performance level is higher in semi-rigid frames as compared to rigid connections. The inclusion for the rigidity in the beam-column can have an impact on the performance of steel moment frames which cannot be ignored during the design and retrofit of steel moment-resisting frames.