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Their initial curvature make steel-cured girder bridges more susceptible to lateral-torsional bucking during construction. Critical in assessing the strength and fatigue life of the bridge components, predicting stresses in the main girders and the crossframes proves more complex than in straight bridges. In this project, researchers investigated the correlation between measured and computed results in a two-span, four-girder, continuous composite steel curved girder bridge with skew supports. A previous phase involved computing the stresses through a linear elastic grillage finite element computer project and comparing the results with a typical third-party curbed girder analysis program. The project's second phase further investigated the correlation between measured and computed stresses by running two additional live load tests on the bridge. This report summarizes research to investigate the behavior of the curved girder bridge system through all phases of construction, as well as to a series of live load field tests. In addition, researchers investigated the effects of change in temperature on the bridge behavior and tracked any changes in behavior of the bridge system over time and under service load conditions.

This research project investigated the effects of pre-release cracks on girder camber, flexural cracking capacity, and steel stress ranges. The research included a parametric study investigating stress ranges in the prestressing strands in uncracked, cracked and partially cracked girder sections to determine if steel fatigue was a concern. An analytical study also was performed, which modeled several pre-release cracks, including models of two experimental girders that developed pre-release cracks, to determine the effect of various cracks on girder stress and camber. The study concluded that steel fatigue in the prestressing strand is a concern in girders that become cracked in service. A loss of compressive stress is believed to occur in the bottom fiber of the girder because of pre-release cracks, which may result in the section cracking at lower applied load. Finite element modeling determined the loss of compressive stress in bottom fiber of girders with pre-release cracks. Analytical models also showed that pre-release cracks remained local to the crack location, that non-linear stress distributions occurred during the process of crack closure, and that the magnitude of the pre-release crack effects depended on the number of cracks, the crack width, and the crack depth.