A comparative analysis of seismic retrofit techniques for reinforced concrete bridge columns

Abstract

Reinforced concrete bridge columns built prior to 1971 cannot withstand earthquake forces due to insufficient transverse reinforcement, poor detailing, and lap-splices in the plastic hinge area. In order to correct this deficiency, these piers must be reinforced by confinement in the axis perpendicular to the longitudinal bars. Experimental research as well as field experience has shown that there are a significant number of technologies that are effective column retrofit solutions for the thousands of bridges worldwide that are in need of upgrade. There is a significant amount of documented research dealing with the technical effectiveness of individual techniques, however, very little research has compared these techniques for cast effectiveness and functionality. This dissertation addresses this issue by analyzing and conducting feasibility assessments of existing technologies, providing detailed retrofit designs for 6 circular and 6 square columns using four different approaches: steel jackets, FRP wrapping, concrete jackets and external pre-stressing and by pricing all of these designs. From this data, conclusions are drawn concerning the cost effectiveness of the four technologies. This study also analyses bridge assessment techniques.