I-25 over Yale Avenue—the Thin Solution

This paper describes how the replacement bridge for Interstate 25 over Yale Avenue in Denver, Colorado, is an excellent example of using high performance concrete (HPC) to meet the demands of urban bridge replacement. In growing urban centers, designers need to replace deteriorating bridges without changing existing vertical alignments, while providing for wider roadway sections on and beneath the bridges. This calls for longer spans at reduced superstructure depths, and bridges that can be built quickly with little disturbance to traffic. The new bridge replaced a four-span, cast-in-place T-girder bridge that was structurally deficient, largely due to deck deterioration. This necessitated traffic closures when portions of the deck fell to the roadway below. The Colorado Department of Transportation (CDOT) needed to build the new bridge without lane closures or grade changes to either I-25 or Yale Avenue because of the high traffic volumes and the restrictive urban setting. CDOT also wanted to improve the vertical clearance over Yale by 18 in. (460 mm). This resulted in a span for the new bridge of 112 ft (34m) with a superstructure depth of only 3 ft (0.9 m).