An innovative substructure design allowed the three-span Wadsworth LRT bridge to be constructed as an integral frame. The design ensured that the spliced and posttensioned precast concrete–girder bridge could efficiently support two rail lines, a bicycle lane, and a new transit station and platform directly above the street.
The bridge is part of the $707 million, 12.1 mi (19.5 km) long West Corridor expansion of the Denver, Colo., light-rail system, which, when completed, will run from downtown Denver to Golden, CO. The bridge is one of a number along the line, but it is the only one with the station on the bridge.
The key superstructure challenge involved balancing the design loadings on the different girder lines to produce a uniform response on a relatively slender superstructure. A detailed three-dimensional analysis was performed to consider the contribution of the concrete platform in the composite cross section. Variable-depth precast concrete–girder segments over the piers added the necessary frame stiffness to allow for the shallow depth of the main span.
Girder layouts and splice locations were designed to provide six lanes of traffic at all times during the work. Construction was accomplished on shoring with minimal disruption to traffic.
This project offered an innovative use of continuous-girder design and integral frame. The biggest concern was live-load deflections, and precast concrete helped to control those deflections.