Replaceable Unbonded Tendons for Post-tensioned Bridges

Published: March 1st, 2018

Category: Research

Post-tensioned concrete is critical to many kinds of construction, such as this box girder bridge

Dr. Trey Hamilton, of the Structural Engineering Group in the UF Department of Civil and Coastal Engineering, along with his research team, investigated the use of flexible fillers with post-tensioned tendons, including performance testing of the materials and methods of installation and inspection. Post-tensioning concrete is an efficient means of increasing the strength of bridges, allowing, for example, concrete girders to span greater distances with thinner sections with the option of using segmental construction methods. Conventional post-tensioning uses a duct placed either inside or outside the concrete section, and after concrete is installed or cast, cables are installed and stressed, and the duct is filled with grout. Several concrete segments can be post-tensioned together in the field to simplify construction of long bridge spans. In recent years, the use of inferior grout and improper grout installation has led to the corrosion of steel tendons, requiring maintenance and repair of some of Florida’s high profile bridges. In response, the Florida Department of Transportation (FDOT) is implementing the use of flexible fillers in critical applications in place of grout. (Source: FDOT project summary)

Click here to view the final report.