Ultimate Strength of Curved RC Box Girder Bridge

Results obtained in a study of a large-scale curved two-span four-cell reinforced concrete box girder bridge model are presented. The model, which was a 1:2.82 scale replica of a prototype, had overall plan dimensions of 72 ft (21 m) long by 12 ft (3.7 m) wide. The radius of curvature was 100 ft (30.5 m). This represents the sharpest curvature normally used for bridges in the California highway system. Experimental and theoretical results are considered for reactions, steel and concrete strains, deflections, and moments due to conditioning overloads producing stress values as high as 2.5 times the nominal design stress. The loading to failure and the ultimate strength behavior is examined. The excellent live-load overload capacity of the bridge is evaluated and comparisons are made with the similar behavior of an earlier tested straight bridge model. Conclusions appropriate for the design of this type of bridge are given.