PROJECT DESCRIPTION

Delta provided multi-discipline engineering services for retaining wall reconstruction along Illinois Route 251 in Rockford, IL. This wall serves as a separation between IL-251, classified as an ‘other principal arterial route’, on the retained side and both the Union Pacific Rail Road (UPRR) and Rock River Recreational Bike Path on the low side.

STRUCTURAL

The existing structure is a reinforced concrete cantilever retaining wall on spread footings with total length of 650’. Retained height varies from 5’ to 14’. Sections 1 and 3, totaling 305’, required significant repairs. A temporary soil retention system was installed on both sides of the existing stem wall to facilitate construction. The existing stem wall was removed, exposing the top of the existing footing to reuse vertical reinforcement. Delta designed the following:

• Existing stem wall removals and excavation
• Proposed stem wall reinforcement details
• Concrete structural repairs including epoxy crack injection
• Temporary soil retention system
• Additional weep hole drainage for 325’ of existing wall

CIVIL

Civil engineering design and PS&E included the following:

• Plan and profile
• Removal of 600’ of existing damaged guardrail
• Addition of 800’ of steel plate beam guardrail
• Maintenance of Traffic (MOT)
• Typical & 50’ interval cross sections
• Erosion control and restoration
• Pavement markings
• PESA (Preliminary Environmental Site Assessment) response including exhibits.

ELECTRICAL

Electrical design required removal of two light poles adjacent to retaining wall reconstruction. Two temporary light fixtures on wooden poles were provided within the project area. The final condition includes two new 47.5’ high poles with 12’ mast arms and LED luminaires.