Evaluating an Inadequate Waterway Opening
The waterway opening provided by the existing structure was inadequate and caused the stream to accelerate as it passed through it. Also, the structure overtopped during major rain events. As a result, the sidewalks adjacent to the structure were being undermined by water piping around the structure, and there was concern that the roadway may also get undermined. Civiltech performed a detailed structural inspection and found the superstructure to be in poor condition with spalling and exposed rebar on the underside.
Designing the Replacement Bridge
There was little opportunity to raise the roadway profile because of the nearby residential driveways. Additionally, the geotechnical investigation found very poor compressible soils to depths of up to 14-ft. As a result, a single span slab bridge founded on driven piles was selected as the replacement bridge type in order to minimize the superstructure height and develop support below the poor soils. The replacement bridge is designed for an HL-93 loading and carries 2 lanes of traffic as well as 2 sidewalks across the creek.
Contract Documents and Permitting
Civiltech provided hydraulic analysis and structural design services for this locally funded bridge replacement. In addition to preparing contract plans and specifications, Civiltech also prepared an Army Corps of Engineering Permit, a Department of Natural Resources – Office of Water Resources Permit, and a DuPage County Stormwater Permit.
Assessing and Protecting the Stream Bank
Civiltech provided Resident Engineering services for the construction phase. The team also performed the maintenance and monitoring tasks for this project which included site inspection, streambank assessment, soil erosion and sediment control surveys, and vegetation surveys.
This Project Incorporates the Following:
- Inadequate waterway opening
- Deteriorated superstructure
- New single span slab bridge
- Bridge design for HL-93 loading
- Multiple agency permitting
- Streambank maintenance and monitoring
Scope of Services
- Structure Inspection
- Bridge Design
- Hydraulic Studies
- Environmental Permitting
- Preparation of Contract Plans, Specifications & Estimates
- Maintenance and Monitoring
- Resident Engineering