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.