Field Evaluation of Near-Surface Mounted, Fiber-Reinforced Polymer Strips for Strengthening of a Continuous Reinforced Concrete Bridge

Abstract

The Letohatchee bridge is a continuous, reinforced concrete, deck-girder bridge maintained by the Alabama Department of Transportation (ALDOT) along AL 97 over I-65 near Letohatchee, Alabama. The bridge is deficient in negative-moment capacity and was strengthened using near-surface mounted fiber-reinforced polymer (NSM FRP) strips.

The bridge was load tested before and after implementation of the NSM FRP strengthening program. A long-term test was also conducted one year after installation to evaluate behavior of the NSM FRP system after a year of exposure to the environment and service loads. Installation of the strengthening system is documented in this thesis.

The NSM FRP system exhibited an apparent 10% reduction in girder reinforcing steel stress, while stress in slab reinforcement may have increased due to a more even distribution of moment across the bridge cross section. The NSM FRP system did not show any signs bond degradation or strength loss one year after installation.