Confining mechanism and section curvature analysis #br#
of steel truss confined concrete composite columns
Rong Chong1,2 Shi Qingxuan1,2,3
1. State Key Laboratory of Green Building in Western China, Xi’an University of Architecture & Technology, Xi’an 710055, China；
2. School of Civil Engineering, Xi’an University of Architecture & Technology, Xi’an 710055, China;
3. Key Lab of Structural Engineering and Earthquake Resistance of the Ministry of Education,
Xi’an University of Architecture & Technology, Xi’an 710055, China
Abstract：Steel truss (ST) confined concrete composite columns have good mechanical and seismic behaviors and the section form can improve material utilization of inner steel section. Based on the existing axial compression experiment, the confining mechanism of ST confined concrete was analyzed. The corresponding models were established, including the lateral confining stress model, bearing capacity model and constitutive model. The low cyclic reversed loading experiment was conducted, based on which the section analysis model was proposed. The influence factors of section yield curvature and section ultimate curvature were analyzed, including the axial compression ratio, concrete strength, angle steel ratio, ratio of batten width to angle steel spacing, ratio of batten spacing to angle steel spacing and ratio of angle steel spacing to batten thickness. Then the calculation formulas of section yield curvature and section ultimate curvature were established. Furthermore, the calculation formulas for the section curvature ductility coefficient and displacement ductility coefficient were proposed and were validated by the tests. The proposed formulas are based on a large number of calculated values and verified by experiment results can consider comprehensive influence factors, which can lay good foundation for the deformation capacity calculation and the displacement-based seismic design.
