CM/GC Repair of Roosevelt Bridge

The Roosevelt Bridge is a precast post-tensioned segmental bridge constructed in balanced cantilever consisting of two parallel structures with 41 spans approximately 4,600 LF each. In June of 2020, FDOT closed portions of the bridge to address emergent repair needs identified during a routine inspection. Cracking was present in one of the spans of the southbound structure which was the result of failed post-tension tendons that had corroded.

The closure impacted 60,000 commuters daily that use the bridge to cross the St. Lucie River. FDOT acted quickly to assemble a team of experts with a goal of completing repairs and re-opening all lanes prior to the Thanksgiving Holiday.

For the first time in Florida’s history, FDOT opted to utilize CM/GC (Construction Manager/General Contractor) collaborative delivery for the project. This approach would ensure continuity in finalizing the repair design through constructability reviews aimed at schedule, cost estimate and minimizing further disruption during construction.

STRUCTURAL TECHNOLOGIES was chosen to perform repairs to the bridge. The team worked closely with FDOT and their Engineers to analyze the bridge and develop a repair procedure to restore the structure’s capacity. STRUCTURAL TECHNOLOGIES designed and installed shoring to support the span and performed bridge jacking and lowering to facilitate the work sequence.

The CM/GC team devised an innovative strengthening solution which involved installing flexible filled external multi-strand post-tension tendons inside the box. The tendons were installed above the bottom slab using new deviation blocks to anchor the tendons. Existing concrete anchorages were demolished and reconstructed. By selecting this strengthening system, the structure would receive protection against corrosion while also allowing FDOT the ability to remove and replace the tendons in the future if needed. Due to the versatility of the external post-tension system, the bridge was able to maintain its aesthetic appearance as the repair did not alter the outward appearance of the structure. In addition to adding external post-tensioning to span 1 southbound, provisional tendons were installed in 17 other spans to strengthen the structures. In total, 48 new external post-tensioning tendons were installed.

Since active recharging water was found at various closure joint locations FDOT requested to epoxy overlay the bridge deck for additional protection. Crews also coordinated roadway related work for asphalt roadways, concrete barrier, traffic signaling, lighting, and striping.

In addition to the strict schedule requirements to restore traffic flow quickly, the team overcame various design and construction challenges. First the team had to assess the load change and how to support the damaged superstructure. In a highly coordinated effort, the team also worked together to sever the existing internal bonded continuity tendons in the span and add new external un-bonded tendons in their place. The project team tackled how to develop the appropriate level of reinforcement for the new tendon anchors while maintaining the shape and integrity of the girder box. In addition, the team had to coordinate the release of temporary supports without disturbing adjacent spans and piers.

The CM/GC team worked together seamlessly to repair and re-open the bridge meeting FDOT’s aggressive schedule to open prior to the holiday. In addition to restoring the capacity of the bridge and enhancing the long-term durability of the structure, the collaborative CM/GC approach saved taxpayers and business owners millions of dollars.