Parametric Study on the Effect of Steel Confinement in Short Bridge Piers Retrofitted with Externally-Wrapped FRP

Department of Civil and Environmental Engineering, Univ. of California Davis, Davis, CA 95616

^* Corresponding author: zignago@ucdavis.edu

Abstract

Confinement of reinforced concrete (RC) piers generally has a beneficial effect on both the compressive strength and the ductility of the confined member. Thus, externally-bonded fiber-reinforced polymer (FRP) wrapping is often used as a retrofit technique for bridge piers when additional compressive strength is needed. This study employs finite element analysis and a recently developed FRP-and-steel confined concrete model to investigate the influence of internal steel confinement on the response of circular RC columns confined with FRP and subject to concentric axial load. This new model leads to more accurate estimates of the response of these columns, what is particularly relevant for piers in short span bridges that are subjected mainly to vertical loads, for which it could lead to a more efficient and economical piers’ retrofit, as well as a more accurate and less conservative bridge rating. A parametric study is conducted to examine the importance of some key parameters in the design of such columns.