CYCLIC TESTS OF CONCRETE-FILLED U-SHAPED STEEL BEAM TO CONCRETE-FILLED SQUARE STEEL TUBE COLUMN JOINTS
Dan Gan 1,2*, Feng Yan 1,2 and Rui Cheng 1,2, Xuhong Zhou 1,2
1Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University), Ministry of Education, Chongqing 400045, China;
2 School of Civil Engineering, Chongqing University, Chongqing 400045, China
This paper aims to investigate the cyclic behavior of a steel and concrete composite joint system connecting square concrete filled steel tube (CFST) columns and concrete-filled U-shaped steel (CFUS) beams. In this study, the composite connection system, in which openings on the square hollow section (SHS) allowed the U-shaped steel beam to be continuous, was proposed. Three cruciform joints with RC slabs were designed according to the strong-column-weak-beam concept and the strong-joint-weak-member seismic design philosophy. The level of axial load in the column and loading procedure were two important parameters to be studied. Test results showed that the joints exhibited good strength, stiffness, deformation, ductility and energy dissipation capacities. The minimum story drift capacity of all the three specimens at 85% of the peak loads was 5.9%, exceeding requirement of special moment frames. All the three specimens failed in a similar failure pattern that the beam bottom flange in the connection zone fractured.
Composite connection; U-shaped steel beam; Concrete-filled square steel tube column; Loading procedure; Cyclic behavior.