Behavior of a 3-Span Continuous Bridge Before and After Continuity Joint Replacement Using Ultra-High-Performance Concrete

Abstract

One method of bridge construction consists of simply supported precast, prestressed concrete girders made continuous for live load through individual continuity joints connecting the two girder ends from adjacent spans. However, creep, shrinkage, and thermal effects can create large positive moments in the joints, leading to severe cracking and potential loss of moment transfer. A bridge in Fort Supply, Oklahoma, utilizing this type of connection was slated for joint replacement, and the Oklahoma DOT elected to use ultra-high-performance concrete (UHPC) for the replacement. To evaluate the effectiveness of the UHPC joint, a load test was conducted before and after joint replacement. The bridge was tested by systematically placing dump trucks filled with crushed stone at the midspan of each continuous span. Deflections were monitored for each test, and strains were monitored in two joints using strain gauges embedded in the UHPC joints during construction. While the measured deflections were small, the strain readings from the postrepair test showed that the UHPC joint was able to effectively provide continuity.