Seismic low-cycle fatigue evaluation of welded beam-to-column connections in steel moment frames through global–local analysis

A general methodology for seismic low-cycle fatigue assessment of welded beam-to-column connection in steel moment resisting frames (SMRFs) is presented. Fatigue deformability curves of seven connection categories are elaborated using the available cyclic tests. Inter-storey drift history imposed on each connection of SMRF is generated by seismic dynamic analysis and adopted in fatigue damage calculation based on Palmgren–Miner’s rule and the experimentally determined fatigue curve. The most critical connection identified by preliminary fatigue evaluation is refined with solid finite elements in global–local model where the cyclic void growth model is integrated to give a more accurate fatigue prediction including load sequence effects. The proposed approach is applicable to fatigue evaluation of welded connections in SMRFs under earthquakes.