Collaboration for Better Bridge Repair

A new method for repairing damaged bridge girders has proven to be effective for restoring girders to their original shear strength and reducing repair costs. This discovery earned researchers with the Minnesota Department of Transportation (MnDOT) a Research Sweet Sixteen Award from the American Association of State Highway and Transportation Officials (AASHTO). Another benefit of this new method is that it avoids lengthy traffic closures for bridge repairs.

Paul Pilarski (MS 1999), Metro North Regional Bridge Construction Engineer at MnDOT, came up with the idea and was the Technical Liaison on the project. His partners included Project Coordinator Bruce Holdhusen from MnDOT and Professor Carol Shield from the University of Minnesota. Shield oversaw the testing of the girders in the Theodore V. Galambos Structural Engineering Laboratory in the UMN Civil Engineering Building.

“Using the new method, severely deteriorated beam ends can be repaired with reinforcement cages and shotcrete for $5,000 to $10,000. The alternative to this type of repair involves constructing a new beam, closing traffic, removing the bridge deck over the damaged beam as well as the beam itself, and recasting the bridge deck and barrier—an intrusive replacement that costs hundreds of thousands of dollars and more than a month of bridge lane closures” (MnDOT Technical Summary). Pilarski commented for MnDot Newsline ("Alternative bridge repair method saves time, money" Nov 14, 2018) that “The fact that we tested good girders alongside repaired girders gives us a high level of confidence in this method.”

The Research Sweet Sixteen candidates are submitted to AASHTO by states. Each of the four Research Advisory Committee (RAC) regions choose the four top projects from their region. The sixteen winning projects are featured in “Research Makes a Difference” publications and at the Transportation Research Board (TRB) Annual Meeting.

MnDOT’s project is documented in MnDOT Technical Summary 2018-07TS, “Affordable Bridge Girder End Repair Method Restores Concrete Beams to Original Strength,” published in April 2018.