Retrofit of Impacted Bridge Girders – KY 562 over I-71

A semi-tractor trailer was transporting a backhoe loader which exceeded the overpass height requirement and impacted the KY-562 Bridge over I-71 in Gallatin County, damaging the bridge girders and severing all the rebars in the bottom of the exterior girder. KTC’s Structures group worked with District 6 to design a retrofit plan to rapidly repair the bridge so that there would be minimum traffic impacts on the interstate. First, the damaged concrete and steel rebars over the northbound lane were removed. CatStrong, a lightweight carbon fiber fabric material, was chosen to wrap the damaged girders to increase their capacity.  CatStrong was applied with epoxy and finished with a UV protective coating. KTC’s structures group oversaw the retrofit construction, which was carried out by five district crew members. The retrofit took two months from the time of the impact damage until project completion. After the retrofit, the moment capacity of the retrofitted beams exceeded that of the as-built beams.

KTC’s Issam Harik submitted this project through the Sweet Sixteen competition, and it is being considered for the High Value Research project compendium. Access his presentation that details each step of the repair process here.