Design Guidelines for Rapid Repair of Earthquake-Damaged Circular RC Bridge Columns Using CFRP

Abstract

The main objective of this study was to develop a rapid and effective repair method using carbon fiber–reinforced polymer (CFRP) fabrics for earthquake-damaged circular RC bridge columns based on apparent damage states. A computational method was developed to estimate the shear resisted by concrete, spirals, and CFRP jacket and the confinement pressure provided by spirals and the CFRP jacket using measured strains at different damage states. It was concluded that even yielded spirals partially contribute to shear strength in damaged columns; however, their contribution to confinement is negligible. Based on this finding, repair design guidelines for standard columns were developed to aid bridge engineers in quickly determining the number of CFRP layers needed based on the apparent damage, column aspect ratio, diameter, and longitudinal steel ratio. In addition, a simple softened steel material modeling method was developed for use in pushover analysis of repaired columns, and good agreement was observed in terms of stiffness, dissipated energy, and strength between the measured and calculated responses.