Seismic behaviors and resilient capacity of CFRP-confined concrete columns with partially debonded high-strength steel rebars

Abstract

To validate the applicability of partially debonded high-strength (PDHS) steel rebars to develop self-centering reinforced concrete (RC) columns, six CFRP-confined concrete columns designed to fail in flexure and two concrete columns without CFRP tube designed to fail in shear were used to investigate the seismic behaviors and resilient capacity of columns under compression and reversed lateral cyclic loading. The experimental results indicate that columns with the partially debonded longitudinal rebars exhibit less seismic damage, better ductility, larger deformability, and smaller residual deformation, as well as smaller energy dissipation at the large deformation stage; meanwhile, the lateral force capacity was smaller compared to the column without the debonding of longitudinal rebars. The strains of longitudinal rebars of specimens with debonded steel rebars were smaller compared to those of the column without debonding at the same deformation stage; moreover, the longer debonding length, the smaller is the strain of the longitudinal rebar. This can explain the great seismic responses and small residual deformations of specimen columns with PDHS steel rebars. The Opensees program can predict the seismic responses of columns with PDHS steel rebars with good accuracy.