The 1,165-foot long Grand Avenue Viaduct, located between Interstate 64 and Chouteau Avenue – spanning Mill Creek Valley, railroad yard and MetroLink tracks – was built in 1959 and had outlived its usefulness. The new bridge is 16 feet wider, has been cut from six to four lanes, and includes a nine-foot-wide irrigated landscape median. Sidewalks have been widened from four to 12 feet. It also has turnouts, so buses can get out of traffic flow to stop and pick-up/drop-off pedestrians. Kozeny-Wagner’s scope included: removal of the existing bridge deck, superstructure, substructure, existing anchorage piers, MetroLink elevators, stair towers and platforms; construction of three new bridges, a single span over Gratiot Street, a three span continuous main bridge over Mill Creek Valley including MetroLink, Union Pacific Railroad, and Burlington Northern Railroad and a single span over Bernard Street; construction of two large fill-sections between the bridges, consisting principally of Expanded Polystyrene (EPS) Geofoam; construction of four decorative towers located on the fill sections.
Early in construction, the team encountered unforeseen conditions, including underground structures that date back to the 1800’s, excessive water table levels and existing utilities. Kozeny-Wagner had to relocate a 30-inch water main the entire length of the project before construction of the new bridge could begin. The existing water main varied from the plans and ran the entire length of the bridge in the location of the new drilled piers. The water main had to be relocated around the piers and bored underneath the railroads. While boring the water line, our team hit underground structures, which turned out to be foundations from the original Grand Bridge built in 1890. Men worked in a tube for days removing obstacles and then fill was pumped into the voided areas. Kozeny-Wagner also had to relocate an existing 48-inch combination sewer line and structure that was in direct conflict with the new bridge’s drilled shafts.
Our team was also confronted with logistical challenges working in minimal temporary easements due to nearby businesses, overhead high powered lines and rail alignments beneath the bridge.