Precast/Pre-stressed concrete repairs have developed in recent years as a response to the increasing necessity for a repair solution to the impact damages inflicted by large vehicles to pre-stressed bridge girders. In the past the only solution was to replace the damaged pre-stressed girder with a new one. This solution was very expensive, time consuming, and required traffic shutdowns and/or detours for extended time.

The main challenge is to repair the broken pre-stressing strands and to restore the required tension in the repaired tendon. The damages strands are cut off to the nearest sound area. The missing portion of each tendon is replaced with a special splicing/tensioning device that grabs and blocks itself onto the two tendon ends that are to be connected. Once the splicing/tensioning device is installed, the tendon is tensioned with the tensioning device that works in a similar manner to a screw jack. As soon as all broken tendons are repaired and tensioned to specification, the concrete is repaired with a high strength repair mortar that can be poured in forms or hand applied.

Applications:	Bridges, Parking Structures, Other impact damaged pre-stressed structures
Benefits:	Restores structure to original load capacity Low cost Minimal installation time required Generates minimal disruption to traffic or plant operation
Sample Project History:	Highway Overpass Girder (PDF)

See also:

Post-Tensioned Concrete Evaluation and Repair Solutions

Post-tensioning Strengthening

Post-tensioning Evaluation