The Illinois Department of Transportation initiated a study to determine the feasibility of widening I-57 (FAI-57) to add a third lane in each direction. Increased traffic volume and truck usage are the main factors for investigating the improvements. Rehabilitation / replacement options for eight at-grade structures, fifteen overhead structures and options for the rehabilitation of three interchanges were also required in the preparation of the study.
In March 2007 Oates Associates completed the study to determine the feasibility of widening I-57 from four lanes to six lanes, over 18 miles. Three alternatives were evaluated for accomplishing the project objectives. Criteria used to determine the preferred alternative included costs, right-of-way and environmental impacts, constructability, and impacts to the public caused by the proposed improvements.
In addition to the study, Oates prepared two Phase I Project Reports, eight Bridge Condition Reports, and five Hydraulic Reports for the structures along this route. Oates took two of these bridges through the final design phase. All of the structures are located in Seismic Performance Category B. The existing four-span structure carrying I-57 over 7th Street will be replaced with a two-span steel beam superstructure. The existing three-span structure carrying I-57 over Union Pacific Railroad will be replaced with a three-span steel beam superstructure.