Investigation of through beam connection to concrete filled circular steel tube (CFCST) column

Nonlinear finite element models of through beam connection to concrete filled circular steel tube (CFCST) column with three types of connection failures (column, beam and joint shear failures) under monotonic loading were proposed by ABAQUS programme. The connection detail composed of a steel I-beam which is completely passed through the circular steel tube column and welded to it by fillet or full penetration weld and the tube is then filled with concrete. The connection parameters investigated included different ratios of column-to-beam flexural strength, fillet or full penetration weld to connect the beam to the tube, using rebar inside of the column and effect of beam web and concrete core inside the joint. Buckling analysis, concrete damage, weld fractured and tube tearing were defined in the model. Good agreement was achieved between the model and existing test results in terms of the beam tip force-storey drift relationship, joint distortion and joint shear strain. As a result, the models could correctly predict the linear, nonlinear and post-failure behaviours of the connection. In addition, other parameters of the connection were investigated for the specimens. Finally, the effect of column axial load level for the connection behaviour in the three types of failures was investigated as a parametric study.