Experimental Investigation on the Force-Crack Quantification Model for HSRC Columns with Flexure-Shear and Shear Failure Modes

A total of six full-scale high strength reinforced concrete (HSRC) columns were tested under axial and cyclic lateral loading. The specified concrete compressive strength was 70 MPa and the specified yield strength was 685 MPa and 785 MPa for the longitudinal and transverse reinforcements, respectively. The main variables considered in the study are the transverse reinforcements ratio and axial load ratio. Although such HSRC columns have gradually transformed in use and scope, the damage assessment method is less understood. The main purpose of this study is to propose a damage assessment model for HSRC columns. An analytical backbone curve model for predicting force–deformation behavior of HSRC columns is described. Column stiffness is also measured from the experiment to obtain stiffness reduction factors that are necessary to calculate member deformation. Based on experiment results, a new limiting value of residual crack width is defined to determine damage level. This study uses specified residual crack width of 0.15 mm, 0.30 mm, and 1.00 mm in the damage assessment model. The new limiting value of residual crack width is also used to determine the performance points of structural members. Finally, a new drift ratio limit of each damage level is also proposed. Experiment results are presented and used to investigate the application of the proposed damage assessment model.