Experimental and numerical study on lateral impact response of concrete filled steel tube columns with end plate connections

The behaviour of concrete filled steel tube (CFST) columns has been investigated intensively against lateral and axial impact loading. However, there is a lack of knowledge on the impact response of the connection between such the column and steel beam. In order to close this gap, the most common connections with a partial depth end plate (PDEPCs), as a simple connection, and a flush plate (FPCs), as a moment resisting connection, were investigated under lateral impact loads. The long bolts were used to connect the CFST column to the beam as an alternative technique to the ordinary bolts. Here, eight specimens were tested under loading conditions with different locations and plate thicknesses. 3D finite element models were then developed and validated against the corresponding experimental results. Full range analyses of the connection response under the loading regime were then carried out using the validated FE models to examine the internal forces and the energy dissipation of the connections. The main findings are as follows: (1) the failure modes of both connection types investigated were similar at both loading locations only with slightly higher tearing fracture on the PDEPC; (2) using a thicker end plate increases the moment capacity of the connection but decreases its energy absorption; (3) the performance of long bolts provides the connection with appropriate ductility up to failure.