Performance Assessment of Retrofitted Drilled Connections Subjected to Ultra-Low Cycle Fatigue Loading

In this research, ultra-low cycle fatigue in retrofitted connections with R-RBS1 and R-RBS2 drilling patterns has been investigated using experimental and numerical methods. The connection was retrofitted with the RBS1 pattern, with a 1% increase in seismic capacity, which failed in the 6% drift angle cycle. While the connection was retrofitted with the R-RBS2 pattern failed in the 5% drift angle cycle. In both connections retrofitted with R-RBS1 and R-RBS2 patterns, the place of damage caused by ultra-low cycle fatigue was in the drilling area.