Experimental investigation on shear-bending performances of concrete-filled thin-walled corrugated steel tubes

Concrete-filled galvanized corrugated steel tube (CFCST), is an innovative composite member, which is proposed for improving the ductility and durability of conventional reinforced concrete (RC) structures. In practice, combined shear-bending loads often exist in a CFCST pier/column. It is necessary to investigate the shear-bending working mechanism of CFCST and access the shear-bending bearing capacity interaction relationships for a more reasonable design. Twenty-seven columns including 21 CFCSTs and 6 TRC specimens are therefore tested comparably. The main test variables are the loading types, shear span-to-depth ratios, tube forms, and the end/support conditions. The test results show that a satisfactory deformative coordination among the core concrete, reinforcements, and CST can be obtained, resulting in a significant improvement in shear-bending performances compared with conventional RC structures. With the discussion of failure modes, deformation curves, load versus mid-span displacement responses, and strain/stress properties of CST, the shear-bending working mechanism of CFCST is particularly addressed. Based on the test results, reasonable design methods for predicting the individual shear/bending strength and the combined shear-bending bearing capacity interaction relationships of CFCST are proposed eventually.