Exposed column-base plate strong-axis connections for small-size steel construction

Experimental study on exposed steel column-base plate connections subjected to both axial and lateral loadings is quite limited. Therefore, based on the intensive field investigation, nine specimens were tested to appraise the seismic performance of various column-base plate strong-axis connections of small-size steel structures in this study. The main parameters were the thickness of base plates, the embedment length of anchor bolts, and the presence of hook and rib plates. Flexural strength, deformation capacity, energy dissipation, and stiffness of the test specimens were investigated. Based on the test results, the hysteretic behaviour of exposed column-base plate strong-axis connections was significantly influenced by the base plate thickness as well as the number and embedment length of anchor bolts. However, the effect of rib plates on the flexural performance of column-base plate connections was negligible. The flexural stiffness of the specimens was approximately 15% of the flexural stiffness by the New Zealand Standard with the assumption that the supports were fixed. It was found that although column-base plate strong-axis connections were properly designed in accordance with design guides, the flexural performance of the connections could be unreliable without sufficient bond capacity between concrete and anchor bolts.