County Prestress & Precast recently played a key role in the completion of a University of Wisconsin Madison engineering study funded by the Wisconsin Department of Transportation (WDOT)’s Wisconsin Highway Research Program. The research appeared in the Spring, 2013 issue of PCI Journal as a peer-reviewed paper entitled “Evaluation of Crack Control Methods for End Zone Cracking in Prestressed Concrete Bridge Girders.” PCI Journal is a highly respected technical journal published by the Precast/Prestressed Concrete Institute.
The project addresses cracking at the ends of prestressed girders. Cracks that may occur in girder ends can compromise the structural integrity of the girder by allowing water to penetrate the structure and corrode the interior steel reinforcing strands. WDOT has recognized girder cracking as a significant issue of concern; however there is currently no settled solution for this problem in the State of Wisconsin.
Study authors Pinar Okunus and Michael G. Oliva approached County Prestress & Precast in late summer of 2011 about helping with their research project. County Materials manufactured three girders to the researchers’ specifications. One of the test girders was equipped with special sensors within the structure in order to measure tension during and after manufacture. The other two were used to test alternative debonding procedures.
The project required close cooperation between UW researchers and students, DOT engineers, and County Prestress & Precast staff. County Prestress & Precast monitored the project for 28 days using sensor reading equipment supplied by the researchers. “(Working jointly) with the UW on a project of this nature was an honor for County Prestress & Precast,” comments Quality Control Manager Chris Kirchner. “Our Eau Claire prestress crew worked very well with the UW and the students that came. It was good to have the students come to our facility because now they understand what goes into a prestressed project. It gave the students the opportunity to experience manufacturing (first hand.) “
Okunus was also pleased with the level of collaboration on the project. “It was a very, very positive experience. They were always willing to help us. They didn’t mind slowing (the manufacturing process) down for us so we could take measurements.
“I’m very thankful (for the industry perspective),” she adds. “Sometimes we would suggest a solution and they would tell us it was not practical. It just demonstrates how important it is for research and industry to work together. “
WDOT is currently considering implementing some of the solutions recommended by Okunus and her fellow researchers as a result of this research.