Performance of flange-welded/web-bolted steel I-beam to hollow tubular column connections under seismic load

Earthquake causes wide and severe damage to building structures due to the great ground motion which is also one of inducements of other extreme events such as fire, tsunami and debris flow. The Multi-extreme loads such as earthquake and the subsequent actions could be much more destructive than the earthquake action itself. Regarding the safety of properties and lives, in order to evaluate building structures subjected to post-earthquake actions, it is important to accurately assess the partial damage caused by earthquake on structural components. By using experimental method, two groups of flange-welded/web-bolted steel I-beam-to-hollow-tubular-column connections were investigated under static and cyclic loadings at ambient temperature. The flexibility and strength of the connections are measured, while the damage phenomena and failure modes are explored during the tests. The connection damage was found to be a cumulative process with fracture extending. The increasing damage led to significant gradual degradation of the connection mechanical properties. The quantificational evaluation was also carried out to investigate the connection damage degree according to different loading intensities. Using finite element (FE) modelling, study was carried out and validated by the experimental results while a good agreement was achieved. The test and FE modelling results in this study provided detailed understanding of the performance of the flange-welded/web-bolted steel tubular connection. It can be used for further investigation of the connections subjected to combined actions of extreme loading such as post earthquake fire.