By: Contech Engineered Solutions
The American Center for Mobility (ACM), recently built a U.S.-based connected and automated vehicle (CAV) research facility in Ypsilanti, Michigan, the heart of the automotive industry. The Center is a proving ground for CAV product testing, development, validation, and certification. The 500-acre site includes a driverless 2.5-mile highway loop, two double overpasses, a railroad crossing, intersections, roundabouts, and a 704-foot long curved tunnel.
The curved tunnel, the largest of its kind, provided by Contech Engineered Solutions, is 704 foot long, 49′-5″ span x 24′-0″ rise Deep Corrugated Structural Plate tunnel with 9 – 4.6 degree elbows. In the preliminary design stages, the engineer coordinated with Contech’s team on different tunnel concepts. The ultimate goal was to create a tunnel where an automated vehicle enters the tunnel, but, cannot identify the exit. Thus, the design of a lengthy, curved tunnel was paramount to the project.
The Deep Corrugated Structural Plate solution was identified as the most cost effective option available to the market. The custom-shaped design was able to meet the required clearance box, include elbows to transition the tunnel and create a lightweight design allowing for the use of a cast-in-place spread foundation. In addition, the entire structure was designed for a Class II natural sand backfill, an economical, locally available material procured by the contractors. The final design of the Deep Corrugated Structural Plate structure included cast-in-place headwalls, a lighting and mechanical system, and external waterproofing.
By utilizing a 2-Radius Arch system, ACM was able to significantly reduce overall construction costs with material, foundation, and installation savings.