The First Avenue Bridge is a 3-span continuous composite prestressed concrete I-beam bridge over Pigeon Creek and the Pigeon Creek Greenway Trail. First Avenue is a main 4-lane roadway in Evansville, Indiana and carries nearly 30,000 vehicles per day. The approaches to this bridge were settling significantly, which had been an ongoing problem because it had been built on approximately 20 feet of fill atop weak, compressed, slightly organic soil.
The bridge itself was stable as it was founded on piling. In previous attempts to correct the settlement problem, concrete, asphalt, and other fill materials were placed in sinkholes to bring the road approaches to the same elevation as the bridge itself. Lochmueller Group recommended a geotechnical study that revealed that the “normally consolidated” material beneath the roadway fill was continuing to compress.
Several repair options were considered to remove the additional weight on the underlying soils, but it was determined that the most economical, long-term solution would be to construct approach spans to the existing structure. These approach spans were designed to span the areas of normally consolidated soils on either side of the bridge, and are founded on H-piles.
In the design of the approach spans, special consideration was given to the locations of existing utilities beneath the bridge and approach roadway. The prestressed concrete box beams were spaced to accommodate these utilities. The bridge deck was scarified and a new bridge deck overlay was placed, railings upgraded, expansion joints replaced, and a new reinforced concrete approach slab was installed at the north approach. A modified approach slab was used on the south approach that abuts the Evansville levee system.