Dixon Avenue Bridge Replacement over Howland Creek

Project Details:

• Location: Dixon Avenue (FAU 5560), Coloma Township, Whiteside County, Illinois
• Existing Structure: 098-3001
• Replacement Structure: 098-3079
• Dimensions: 57′ wide (4 traffic lanes + 2 x 3′ shoulders + 18″ curbs) x 108′ 4″ long (3 spans)
• Average Daily Traffic: 3,150 vehicles
• Speed Limit: 40 mph
• Road Type: Minor Arterial

Challenges:

1. Traffic Volume and Safety: With an average daily traffic of 3,150 vehicles, the existing bridge could no longer meet the demands of local commuters and heavy vehicles. The narrow lanes and lack of shoulders posed a safety risk, especially for cyclists and pedestrians.
2. Structural Integrity: The aging structure had reached the end of its service life and required replacement to avoid the potential for failure. The existing bridge’s three-span design with limited shoulder space presented further challenges in terms of both structural integrity and safety.
3. Construction Timeline and Logistics: The bridge is located on a major arterial route in Whiteside County, requiring careful planning to minimize traffic disruptions. A significant challenge was ensuring that construction would proceed efficiently while maintaining adequate access to the community and avoiding major delays for commuters.
4. Environmental Considerations: The bridge spans Howland Creek, an environmentally sensitive area. The design and construction process needed to comply with environmental regulations to minimize any impact on the creek and surrounding areas.

Solution:

The Whiteside County Highway Department, led by County Engineer Russ Renner, PE, SE, worked with design consultant Keith Brandau, PE, SE, from Chastain & Associates, to develop a modern solution for the Dixon Avenue Bridge. The general contractor, Jared Martin of Martin & Company Excavating, was tasked with the construction, while resident engineer Jeff Spensley from Chastain & Associates oversaw the project to ensure it met the county’s specifications and deadlines.

1. Bridge Design: The replacement bridge features a 57-foot wide design with 4 traffic lanes, 2 x 3-foot shoulders, and 18-inch curbs. The wider bridge accommodates current traffic volume while allowing for future growth. The three-span design is 108 feet 4 inches long, providing ample clearance over Howland Creek and improving hydraulic flow.
2. Superstructure: The new bridge utilizes a composite 8-inch precast concrete deck supported by 18-inch Valmont U-BEAM Tub Girders. This design ensures long-term durability and low maintenance while offering the strength necessary to support daily traffic loads.
3. Safety Features: The wider bridge includes additional safety measures such as the inclusion of shoulders, providing space for emergency vehicles, pedestrians, and cyclists. The improved structure enhances safety for all road users, especially considering the 40 mph speed limit and significant vehicle volume.
4. Environmental Compliance: The project design adhered to environmental regulations, ensuring minimal disruption to Howland Creek and the surrounding ecosystem. Efforts were made to protect water quality and reduce soil erosion during construction, preserving the environmental integrity of the area.
5. Traffic Management: To minimize disruption, the project team developed a phased construction plan. The existing bridge remained in use while portions of the new structure were being built, allowing traffic to flow with minimal interruptions. Temporary detours and careful coordination with local authorities ensured that access to nearby areas was maintained.

Outcome:

The replacement of the Dixon Avenue Bridge over Howland Creek has greatly improved the safety, efficiency, and reliability of the crossing, benefitting both the community and regional traffic. The new bridge now meets the current traffic demands and provides ample room for future growth. Key outcomes of the project include:

• Improved Traffic Flow: The wider bridge accommodates increased traffic and provides safer passage for all vehicles. With 4 traffic lanes and designated shoulders, the bridge can handle both current and projected traffic volumes.
• Enhanced Safety: The addition of shoulders and curbs enhances the safety of all road users, including drivers, pedestrians, and cyclists. The wider lanes also reduce congestion, particularly for large vehicles.
• Increased Durability and Reduced Maintenance: The use of precast concrete and U-BEAM Tub Girders ensures the bridge’s longevity and minimizes future maintenance needs, reducing long-term costs for Whiteside County.
• Environmental Preservation: The design was executed with environmental sensitivity, ensuring minimal impact on Howland Creek and the surrounding area. The project complied with all necessary environmental guidelines to protect local ecosystems.
• Community Impact: The successful replacement of the Dixon Avenue Bridge has improved the infrastructure in Whiteside County, providing a safer and more efficient route for local commuters and regional traffic. The project was completed with minimal disruption to traffic, and access to local businesses and residences was maintained throughout construction.

Lessons Learned:

• Thorough Planning for Traffic Management: The phased construction approach allowed the project to be completed on time while minimizing disruptions to local traffic. Advanced planning and communication with the community were essential to keeping the project on track.
• Durable, Low-Maintenance Design: The use of precast concrete and U-BEAM Tub Girders proved to be an effective choice for providing long-term durability with minimal maintenance requirements.
• Environmental Considerations: Protecting Howland Creek and its surrounding area was a priority, and the project adhered to strict environmental guidelines to ensure minimal impact on the local ecosystem.

The successful completion of the Dixon Avenue Bridge replacement over Howland Creek has provided Whiteside County with a safer, more efficient, and more reliable crossing. The new structure ensures that the bridge can continue to meet the needs of local traffic and serves as a model for future infrastructure projects in the region.