Externally Bonded FRP Composites for the Rehabilitation of Reinforced Concrete T-beam Bridges

摘要

This paper presents a synthesis of findings from an ongoing Pennsylvania Department of Transportation District 3 (PennDOT-D3) project to utilize externally bonded FRP composites for the rehabilitation of reinforced concrete T-beam bridges. Identifying a method for selecting candidate bridges for suitability of repair is based on current NCHRP 514 studies. Three levels of repair are identified, Level 1 (contract), Level 2 (contract/Department force), and Level 3 (Department force). From this methodology, a candidate bridge was selected for a contract repair project. Field and laboratory testing of existing bridge materials is described. Pre-repair tests include ultrasonic pulse velocity and rebound hammer on beam concrete, compressive strength tests on deck concrete cores, carbonation tests for both beam and deck concrete, SEM-EDX analyses for beam and deck concrete, and tension tests of the extracted reinforcing steel. Structural analysis was based on AASHTO specifications. Finite Element (FE) modeling was performed to determine existing capacity and the FE model was calibrated by testing of the bridge using applied truck loads. Initial FRP design was based on strengthening to replace a known area of corroded reinforcement. The FRP repair system was designed based on current ACI 440.2R-02 design guidelines. Repair work and post-construction load testing were completed, and supporting full-scale lab studies are ongoing. Results from the rehabilitated bridge and supporting testing will be used to develop draft PennDOT design standards and construction specifications and to apply "lessons learned" to the design and constructability of future T-beam rehabilitation projects.