Problem: A 450-ton load exceeds the weight limit on a prestressed concrete bridge. The bridge is the only shipping route available. Solution: Strengthen the bridge deck by gluing steel plates to the underside of the deck. The 150 steel plates installed transversely across the bridge deck were 16 inches wide, 0.4 inch thick and about 9 feet long. They were first suspended beneath the bridge by threaded bars. Epoxy adhesive was applied to the underside of the bridge and to the top of the steel plates which were then pressed up against the bridge deck by tightening nuts on the threaded bars. For the epoxy adhesive to be effective, all contact surfaces had to be clean. To remove laitance and to expose aggregate, the concrete was shotblasted or mechanically scabbled.