Axial compressive behavior and parametric analysis of spiral reinforcement concrete filled square steel tubular columns
Chen Zongping1,2 Jing Chenggui1 Ning Fan1
1. College of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China;
2. Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education, Guangxi University, Nanning 530004, China
Abstract：To investigate the axial compressive behavior of spiral reinforcement confined concrete filled square steel tubular (SRCFSST) stub columns, a total of 23 specimens were designed to test under axial load. Six parameters were considered, including spiral reinforcement spacing, diameter, ratio of the spiral diameter to the square tube width, square tube width, concrete strength and longitudinal bar. Based on the tested data, the effects of design parameters on axial compressive behavior of SRCFSST were analyzed, and in the ductility part the energy-based ductility factor was introduced. The experiment results show that the failure modes of SRCFSST columns are similar to those of concrete filled square steel tubular columns. When the spiral reinforcement ratio over 1.5%, the type of load-displacement curves by falling into strengthening, and there appeared four feature points in load-displacement curves as the obvious sign before the damage. Under the condition of increasing the same weight of steel, with the increase of content of spiral reinforcement, the bearing capacity, peak strain and ductility were greatly increased, while increasing the content of steel or longitudinal bar, only the bearing capacity improved slightly, and the peak strain and ductility stayed almost unchanged. Based on the parametric analysis results, the design suggestions was proposed for optimal configuration of steel in axial compressive member adopted SRCFSST.
