A Study on the Shear-Failure of Circular Sectioned Bridge Column Retrofitted by Using CFRP Jacketing

Abstract

In this paper, analytical and experimental studies on the shear-failure and confinement of circular section RC bridge columns retrofitted by carbon fiber reinforced plastic (CFRP) jacketing were performed. An effective confined concrete constitutive model named Modified L-L Model proposed by Li et al. (Li, Y.-F., Lin, C.-T. and Sung, Y.-Y. (2003). A Constitutive Model for Concrete Confined with Carbon Fiber Reinforced Plastics, Mechanics of Materials, 35:603–619.) is introduced and used to determine the thickness of CFRP for retrofitting bridge columns, and to analyze the lateral force–displacement relationship of circular sectioned bridge columns. In the Modified L-L Model, the lateral confinement of the concrete comes from both steel reinforcement and CFRP composite material. Three 40%-scale bridge columns with shear-failure mode were tested under cyclic loading at the National Center for Research on Earthquake Engineering (NCREE). The analytical lateral force–lateral displacement relationship of bridge columns using the Modified L-L Model can predict the lateral force–lateral displacement relationship of experimental result very well, and the prediction shows that the Modified L-L Model can be used in seismic retrofit analysis. In the meantime, the performance of retrofitted bridge columns can be greatly improved by using CFRP composite material.