Monroe County, Florida

The State Road 5/Overseas Highway is the only link between the Florida Keys and the mainland. Along this route, four precast segmental concrete bridges were constructed in the late 1970’s; Channel 5, Long Key, Seven Mile and Niles Channel. In 1999, a failed tendon was found in the Niles Channel Bridge and in 2000, two tendon failures were found in the Mid-Bay Bridge in the panhandle of Florida. As a result, FDOT implemented a statewide initiative to assess post-tensioning corrosion in their segmental concrete bridges. Corven Engineering was selected to perform an initial inspection (vibration testing, pour-back removal and non-destructive visual inspections using endoscopes), evaluation, implementation of the remediation and inspection of the remediation of the four Florida Keys segmental concrete bridges. The four segmental concrete bridges have a total of 445 spans, each built span-by-span with external post-tensioning. Span lengths range from 81′ to 141′. There are a total of 2514 tendons.

Corven Engineering Role: Post-Tensioning Evaluation and Remediation, Load Rating. Inspection, evaluation and remediation services for the post-tensioning system (PCL Civil Constructors performed the remediation as a subconsultant to Corven Engineering).