Institute for Transportation

About the research

The objective of this project was to demonstrate the field implementation of an innovative longitudinal joint design developed during a previous phase of research. To achieve this objective, a yet-to-be-constructed box girder bridge in Washington County, Iowa, was selected to demonstrate the construction and performance of the joint.

In order to evaluate the joint’s performance, a seven-day period of field monitoring was conducted shortly after construction was completed. In addition, long-term evaluation of the joint was performed through the completion of live load field tests and deck concrete crack inspections. The live load tests were performed every 12 months, and crack inspections of the bridge deck were performed every six months. During the field tests and monitoring, temperature, strain, and displacement data were collected at critical locations and analyzed to evaluate joint performance with respect to cracking resistance and load distribution.

The results indicate that the innovative joint is sufficient to resist early-age longitudinal joint cracking. Joint cracks that were seen on another box girder bridge with traditional narrow joints were not observed in this case. The innovative joint performed well with respect to load distribution. The whole bridge superstructure behaved as an integrated structure regardless of the transverse location of a passing truck. In addition, the box girder bridge was constructed using integral abutments, which added transverse restraint and positively affected the strain distribution at the joint ends.