By: Contech Engineered Solutions, Inc
Project Summary
The 2023 DOT Project of the Year transformed a deteriorating historic bridge into a modern transportation asset while preserving its character and supporting redevelopment in Bridgeport, Connecticut. A custom deep corrugated steel buried bridge allowed Connecticut DOT to meet complex design requirements that other solutions could not.
A DOT Project of the Year Decades in the Making
The 2023 NCSPA DOT Project of the Year demonstrates how innovative engineering can solve long-standing infrastructure challenges.
Submitted by Contech Engineered Solutions, the Yellow Mill Bridge project in Bridgeport, Connecticut, rehabilitated a historic concrete arch structure while widening the roadway above to improve traffic flow and support future redevelopment. Although the project reached substantial completion in 2022, planning and evaluation efforts stretched back to the early 1990s.
The crossing carries U.S. Highway 1 over Yellow Mill Channel and a former rail corridor near the historic Remington Arms property. As redevelopment efforts gained momentum throughout the area, Connecticut DOT recognized the need for a long-term solution that could preserve the bridge’s historic appearance while improving transportation infrastructure.
Balancing Historic Preservation with Modern Transportation Needs
The original concrete arch structure was constructed in 1910 and rehabilitated several times throughout its service life. By the time planning for the latest rehabilitation began, the bridge faced a unique combination of structural, geometric, and community challenges.
The replacement structure needed to fit inside the existing arch while maintaining clearance requirements for a future rail-to-trail conversion below. Designers also needed to preserve the structure’s 25-degree skew at both ends, widen the roadway above, maintain pedestrian and vehicular traffic during construction, and accommodate future development plans throughout the surrounding area.
Several alternatives were evaluated over the years, including conventional bridges, precast concrete arch liners, cast-in-place concrete liners, and other rehabilitation approaches. However, none could satisfy all project requirements while remaining economically and technically feasible.
Projects such as Interstate Drainage Access MDT Wolf Creek Named Connections Project of the Year demonstrate how transportation agencies increasingly seek infrastructure solutions that balance long-term performance, constructability, and community needs.
A Custom Buried Bridge Solution
In 2016, Connecticut DOT approached Big R Bridge, now part of Contech Engineered Solutions, to evaluate whether a structural plate solution could meet the project’s demanding requirements.
Working closely with DOT engineers, the team developed a custom BridgeCor deep corrugated steel buried bridge capable of fitting within the existing structure while maintaining critical channel and trail clearances. The design also accommodated the required roadway widening and future viewing plaza improvements.
As the project evolved, Connecticut DOT and Contech collaborated extensively on geometry development, material selection, design inputs, secondary protection systems, and construction methods. That partnership helped ensure the final design met both engineering requirements and construction realities.
The project highlights the adaptability of deep corrugated structural plate systems for complex transportation infrastructure applications where conventional solutions may fall short.
Collaboration Drives Project Success
One of the most notable aspects of the project was the level of collaboration between Connecticut DOT and Contech throughout the design process.
Rather than relying solely on traditional specification development, the DOT actively sought input during each phase of design. This collaborative approach allowed the team to leverage Contech’s experience with buried bridge systems while maintaining full control of the project design.
The result was a customized solution tailored specifically to the site’s constraints and long-term objectives. The experience also provides a potential model for future DOT projects where owner involvement and manufacturer expertise can work together to improve project outcomes.
Innovative Construction Under Challenging Conditions
Construction required a carefully staged approach to maintain traffic while installing the new structure.
Crews assembled the structure one ring at a time outside the north end of the existing bridge before applying a bituminous secondary coating for additional protection from deicing salts. The completed sections were then pulled through the existing structure until reaching their final position.
After assembly, contractors constructed skewed concrete headwalls and used controlled low-strength material (CLSM) to fill the space between the existing structure and the new buried bridge. The use of CLSM was later expanded throughout the full length of the structure to accelerate construction and provide a consistent support material.
This innovative approach allowed the project team to overcome significant site constraints while minimizing disruption to the traveling public.
Supporting Bridgeport’s Future
Even before construction was fully completed, the project was already delivering benefits to the surrounding community.
Traffic congestion improved, redevelopment activity increased, and property values began rising throughout the area. The rehabilitated crossing now serves as a key component of the Mill Hill Revitalization Plan and will continue supporting future growth throughout the corridor.
The project demonstrates how transportation infrastructure investments can do more than address structural needs. They can also help unlock economic development opportunities and improve quality of life for surrounding communities.
Similar community-focused transportation investments can be found in the 2024 DOT Project of the Year: Exit 41 Interchange and Gilman Springs Road Rebuild Earns Top Honors with Custom Beveled Steel Drainage Pipe, both of which improved infrastructure while supporting future growth.
For Connecticut DOT, the Yellow Mill Bridge rehabilitation delivered a durable, cost-effective solution that preserved history while preparing the corridor for the future.