I-74 Bridges over Market Street & ICRROak Street
CATEGORY: Structural Systems
OWNER: Illinois Department of Transporation
PROJECT FIRM: EXP
DESCRIPTION: In August 2020, the Illinois Department of Transportation (IDOT) undertook major reconstruction project for a crucial piece of Champaign-Urbana infrastructure: the Interstate 74 Bridges over the Illinois Central Railroad (ICRR) and Oak St and over Market Street. I-74 is a major thoroughfare with an average traffic volumne of over 63,000 vehicles per day, serving as critical transportation infrastructure for the community. Originally constructed in the mid-1950’s and widened in the 1990’s, the I-74 bridges over ICRR/Oak Street (SN 010-0021) and over Market Street (SN 010-0020) were deemed structurally deficient. The ICRR bridge was supported on shoring at one severely deteriorated pier. Rehabilitation was urgently needed to maintain safety and functionality of these critical structures on the National Highway System. The ICRR/Oak St bridge consisted of a 3-span continuous steel girder structures panning over an 18-track rail yard and a single span over Oak Street; the Market Street was a 3-span continuous steel beam structure over Market Street that had substandard vertical clearance. EXP provided Phase I and II engineering services, performing comprehensive bridge inspections and condition assessment and developing a Phase I Project Report based on the recommendations and requirements of the recommended scope of improvement form the Bridge Condition Reports. Based on the approved Phase I, EXP developed final contract plans, specifications and cost estimates for rehabilitation of both structures. The rehabilitation consisted of replacement of superstructures on both bridges, reconstruction of a deteriorated pier and repairs of remaining substructures. Market St bridge was reconstructed as a jointless bridge with semi-integral abutments, while the ICRR bridge superstructure was replaced with a 4-spancontinuous structure eliminating the expansion joint over a pier. The design and construction of the new I-74 bridges is a sterling example of a timely and well-executed asset management project where selective reuse of existing substructures eliminated significant hurdles and challenges of working within a busy railroad yard. The project also highlighted the efficiency derived from having the preliminary and final engineering performed by the same team, where the insights and experiences gained from the preliminary phase helped expedite the preparation of plans, specifications, and estimates on an accelerated schedule, allowing the team to complete the final design within three months of Phase I Design Approval.