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Illinois Route 127 over the Kaskaskia River Replacement

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Modjeski and Masters provided final design services for the complete replacement of the structure, vertical and horizontal alignment adjustments, and re-alignment of two nearby intersections. Originally built in 1929 and rehabilitated in both 1964 and 1990, the previous structure was a 23-span multi-girder bridge. 

The scope of services included a Superstructure Type Study (composite steel plate girders were selected for the replacement), research of Accelerated Bridge Construction techniques, completion of the Type, Size and Location Plans, and final design of the replacement structure and affected roadways.

Due to the overall length of the structure and its existing condition, the decision was made to close the bridge during construction. M&M worked closely with IDOT to develop a construction plan to reduce the structure closure. During the first stage of construction, piers were constructed beneath the existing structure while it remained open to traffic utilizing micropiles to accommodate the limited vertical clearances below the bridge.

To provide a safe detour route for stage II, the intersection of Slant Road was realigned with Illinois Route 161. During stage II, the remaining portions of the substructure and the entire superstructure were constructed. Jonathan Road was realigned at the south end of the structure to meet current design requirements.

Bridge Geometry
Total Length of Project 6.26 miles
Lanes on Structures 2 lanes

To assist IDOT with procuring all available funding, M&M expedited the design phase and completed final design in three months.

-Jerilyn Hassard, PE, SE, M&M Project Manager