An Evaluation of Repair Methods for Cantiever Bridge Piers

Susan E. Scott, Brad Wood, and Michael E. Kreger


In an earlier phase of Project 1364, during the process of testing reduced-scale cantilever bent specimens that were models of selected bents used in the San Antonio Y Project, a flaw in reinforcement details was discovered in the joint region of several cantilever bents. The two types of bents that contained this detailing flaw included reinforced concrete bents and bents utilizing post-tensioning in the overhang. Due to inadequate anchorage of longitudinal reinforcement in the column of the post-tensioned bents and in the column and overhang of the reinforced-concrete bents, tensile forces in the column and overhang were not able to be transferred through the joint once loads inparted by the superstructure reached slightly more than service level. A number of repair schemes were developed to remediate this problem in both the reinforced and post-tensioning bents. The most promising of these schemes (namely, external vertical post-tensioning external diagonal post-tensioning, and internal vertical post-tensioning) were fabricated and installed on the damaged reduced-scale cantilever bents, then were tested to factored loads/ φ. All tested repair schemes resisted the maximum test load with no indications of distress. Results of the load tests are presented, and the tested repair schemes are evaluated based on serviceability, cost, constructibility, apparent durability, and aesthetics.

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