Mathon Drive Bridge Replacement

Mathon

Baxter & Woodman provided Phase I Project Development Report, Phase II Design, and Phase III Construction services for a superstructure replacement with a Group II Categorical Exclusion. The Mathon Drive structure consists of a four-span, continuous steel girder bridge approximately 70 feet wide and 350 feet long. The bridge spans a rail yard with nine sets of active railroad tracks below.

The concrete median was removed to accommodate new on-street bicycle lanes connecting the City’s downtown to the lakefront. Federal STP funds were added to the project to reconstruct Pershing Road and to allow the construction of a new multi-use path. Coordination with local agencies, including IDOT, Illinois Commerce Commission, and the Union Pacific Railway, was ongoing throughout the project.

The Phase I work included a preliminary bridge design to evaluate several unique aspects of the proposed bridge. The bridge is flared at each end to accommodate turn lanes, so the new structure will include a flared girder layout accounting for torsion at each field splice. The team also determined that the new bridge could eliminate the bridge deck expansion joints by converting the abutments to semi-integral configuration. The existing foundations and piers were analyzed to confirm that the revised span layout and modern design loads would not over-stress the existing elements. Finally, the bridge was laid out to be replaced in two stages, to allow the contractor to complete the work without requiring access to the rail yard below.