Experimental investigation of full-scale concrete columns confined by high-strength transverse reinforcement subjected to lateral cyclic loading

Abstract

The use of high-strength longitudinal and transverse reinforcements in confined concrete columns can improve bearing capacity and deformability. Besides, experiments on confined concrete columns with side length of 400 mm can better reflect the behaviour of confined concrete columns in engineering project. Thus, the purpose of this study is to investigate the seismic behaviour of full-scale confined concrete columns with high-strength longitudinal and transverse reinforcements. Based on 15 confined concrete columns subjected to lateral cyclic loading, the effects of axial compression ratio, shear span ratio and volumetric ratio on the seismic behaviour of confined concrete columns were studied. The results showed that the ultimate drift ratios of the 15 confined concrete columns ranged from 1/43 to 1/20, i.e. 1.2–2.5 times as much as the specified limit (1/50) of rate earthquake, indicating excellent ductility. Additionally, the high-strength transverse reinforcements could not yield at peak load but could yield at the ultimate displacement. The high-strength transverse reinforcement stresses at the peak lateral load were 430–690 MPa, approximately 56–91% of the transverse reinforcement yield strength. Finally, an empirical formula was proposed to predict the ductility factor that was then evaluated by comparing the predicted values with the experimental results of 37 confined concrete columns.