MIDBAY BRIDGE EVALUATION

Okaloosa County, Florida

Spanning the Choctawhatchee Bay near Destin, Florida, the Mid-Bay Bridge is a toll facility that acts as a primary transportation system used for commuting and traveling between I-10 and Destin. The 3.6 mile long, precast segmental concrete bridge was opened in 1993 and provides for two 12′ lanes of traffic. In 2000, during a routine inspection, two tendon failures were found. Corven Engineering was selected to assist FDOT with the assessment of the post-tensioning system. The 19,265′ long segmental concrete bridge has 135′ long typical spans and a 225′ long main-span over the Intracoastal Waterway. The approach spans were built span-by-span and the main-span unit was built in balanced-cantilever. Precast, post-tensioned I-shaped piers were used for the high-level piers.

Corven Engineering Role: Post-Tensioning Evaluation, Load Rating. Provided a detailed review of the post-tensioning system, structural analyses, on-site reviews, analysis of in-depth post-tensioning tendon inspections to produce recommendations for the rehabilitation for the bridge, and a load rating. Rehabilitation included tendon replacement, tendon wrapping, vacuum injection of anchorages, and post-tensioning anchorage protection.