Experimental investigation of special-shaped concrete-filled steel tubular column to steel beam connections under cyclic loading

This paper presents experimental investigation and numerical investigation on seismic behavior of special-shaped concrete-filled steel tubular (CFST) column to steel beam joints. Exterior diaphragm and vertical rib are respectively introduced as joint stiffeners. A pseudo static experiment was conducted to investigate load transmission mechanism, failure mode and seismic performance index based on load-deformation curves and strain curves. The seismic behavior of the two kinds of joints were compared and evaluated. The classification of the joints by stiffness is conducted according to Eurocode. Inter-story drift of the specimens was calculated with data from laboratory apparatus and verified with test results. A design formula of joint shear resistance based on internal load transmission was proposed for engineering application. A finite element model of special-shaped CFST to steel beam connections was established as a supplement to analyze load transmission mechanism.