Axial compressive behavior of pre-damaged concrete-filled square steel tube columns repaired with section circularization and CFRP composites: Fid-Bau Portal

Axial compressive behavior of pre-damaged concrete-filled square steel tube columns repaired with section circularization and CFRP composites

Zhao, Kang / Hu, Zhongjun / Wang, Boxin / Liao, Weicheng / Xu, Yan

Abstract

Highlights • The effective reuse of pre-damaged CFSST columns was investigated in this study. • The section circularization method was selected to repair pre-damaged CFSST columns. • Testing parameters consisted of pre-damage levels, CFRP layers, and repair ways. • The axial stiffness and bearing capacities of the repaired CFSST columns were studied. • A model was suggested to predict the bearing capacities of the CFRP-SCCFSST columns.

Abstract This study focused on repair treatments for the effective reuse of damaged concrete-filled square steel tube (CFSST) columns with carbon fiber-reinforced polymer (CFRP) composites. Forty specimens were designed to investigate the effects of pre-damage levels, section circularization, and the number of CFRP layers on the compressive behavior of the repaired CFSST columns. Test results indicated that the method of section circularization and CFRP wrapping effectively restored the degraded initial axial stiffness of the pre-damaged CFSST columns and increased the ultimate bearing capacity of the pre-damaged CFSST columns by 49–180 % compared to their undamaged condition. Considering the influence of the pre-damage level and the contribution of section circularization, the ultimate bearing capacity calculation model was suggested for predicting the compressive behavior of the repaired CFSST columns. The experimental results and collected test data have well verified the accuracy and applicability of the calculation model.