Pratt Road Bridge Replacement, Ph. I, II

City of Sandwich

OBJECTIVE

The existing Pratt Road Bridge over Somonauk Creek has a sufficiency rating of 49.3 and requires replacement. The structure was constructed in 1967 and, due to its low sufficiency rating, is eligible for funding through the Illinois Special Bridge Program, which will be used to fund the replacement.

PROJECT DESCRIPTION

HLR provided Phase I and II engineering services for the replacement of the Pratt Road Bridge over Somonauk Creek in the City of Sandwich, resulting in the removal of a structurally deficient bridge and elimination of load posting restrictions for large commercial and agricultural vehicles. The project was funded through the Illinois Special Bridge Program and required coordination with IDOT District 3 and the Federal Highway Administration to meet federal aid requirements.

The proposed structure is a 122-foot-long, three-span bridge with precast prestressed concrete deck beams, spill-through abutments, and in-water piers. The design minimized impacts by limiting roadway profile adjustments and avoiding the need for an individual Army Corps of Engineers permit. HLR completed all required engineering and environmental documentation, including a Project Development Report, categorical exclusion, hydraulic modeling, and a Preliminary Bridge Design and Hydraulic Report.

HLR also led public coordination, detour planning, and right-of-way acquisition, and prepared final plans and specifications for the November 2025 State Letting. Construction is scheduled for completion in summer 2026.