Technical Description:
• BridgeCor
® Structural Plate
• Span: 49-ft. 6-in.
• Rise: 24-ft.
• Length: 702 ft.
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According to the preliminary annual studies from the National Highway Traffic Safety Administration (NHTSA), traffic fatalities were up nearly 8% in 2014, with 35,200 people dying in traffic accidents in 2015. Of those, the most significant increases were for pedestrians and bicyclists. Hoping to decrease the number of car accidents, automakers have begun testing driverless technology at a newly constructed test track facility in Michigan.
Throughout 2017, the American Center for Mobility (ACM), built a U.S.-based connected and automated vehicle (CAV) research facility in Ypsilanti, Michigan, the heart of the automotive industry. The recently opened campus is a proving ground to the growing CAV technology market, allowing for product testing, development, validation, and certification. The 500-acre, driverless proving ground includes a 2.5-mile highway loop, two double overpasses, a railroad crossing, intersections, roundabouts, and a roughly 700-foot long curved tunnel.
The curved tunnel, provided by Contech Engineered Solutions, was comprised of a 702 foot long, 49'-6" span x 24'-0" rise BridgeCor® Deep Corrugated Structural Plate tunnel with 9 - 4.5 degree elbows. In the preliminary design stages, Mannik & Smith 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.
Initially, the project team reviewed precast concrete arch and plate solutions targeting a 50 ft span creating a minimum clearance box 32 ft wide and 15 ft high. Clearance box requirements was only one factor driving the proposed solution. With the Willow Run site being an abandoned brownfield area, the environmental impact of the foundation system was a primary concern. Throughout the site, the existing soils varied in consistency and levels of contamination. The Mannik & Smith team understood that a deep foundation system would be not only cost prohibitive, but would also create other potential onsite environmental issues.
Contech's BridgeCor solution was identified as the most cost effective option available to the market. The custom-shaped BridgeCor design was able to meet the required clearance box, included elbows to create a curved alignment and created a lightweight design allowing the use of a cast-in-place spread foundation. In addition, the entire structure was desiged for a Class II natural sand backfill, an economical, locally available material found locally by the contractors. The final design of the BridgeCor structure included cast-in-place headwalls, a lighting and mechanical system, and external waterproofing.
By utilizing a BridgeCor 2-Radius Arch system, ACM was able to optimize overall construction costs with material, foundation, and installation savings. For the past 80 years, Contech MULTI-PLATE® has been the buried bridge standard. BridgeCor enhances the established performance of 6" x 2" MULTI-PLATE by offering nine times the stiffness and three times the strength. Structural plate has proven its bolted, segmental construction to be economical and efficiently assembled by local contractors. BridgeCor is manufactured with the industry’s best equipment allowing for the longest laying length sheets in the industry.
The Willow Run site is rich in innovation history and formerly housed an advanced aircraft manufacturing facility built by Henry Ford during World War II. In the 1950s, it was redeveloped by General Motors as a powertrain plant, operating until its closure in 2010. In January 2017, the U.S. Department of Transportation designated the center as one of 10 proving grounds to develop and test self-driving cars.
"Just as Michigan put the world on wheels, today we are leading the way in the mobility revolution," stated Michigan Governor Rick Snyder. "ACM will be the place where innovations go from the drawing board to the open road. With ACM open for testing, we are taking one giant step in the right direction to affirm Michigan's place as the undisputed leader in mobility."
The BridgeCor 2-Radius Arch system purchased by Z Contractors is 702 feet long and comprised of 163 rings with seven plates per each ring, a total of 1,141 plates. With pre-installation guidance from Contech, Z Contractors was able to assembly 8-9 rings per day, approximately 30’. With one crew divided into teams per side of the structure, each of the haunch pieces were assembled and then a three piece crown was then capped to minimize the number of bolts needed to be placed 24’ in the air. With Contech’s Winchester, Kentucky plant conveniently located within hours of the jobsite and constant communication with Z Contractors, Contech was able to deliver plates in pre-colored coded sections, keeping 20’ ahead of the crew at all times and eliminating any confusion as to which pieces were for what section. As the structure was assembled, each ring was verified by Z for both the 49’11” span and 24’0” rise to be achieved, each ring was built within 2” of the span/rise combination, well within tolerance of a structure of this size.
While Z Contractors was assembling the BridgeCor structure, Angelo Iafrate Construction Company began the backfill process, taking care to keep the assembled shape at least 75 ft away from the end of the tunnel. The backfill process required 8-10” lifts, compacted to 90% SPD in balanced loads. Iafrate was able to maintain the shape throughout the process and complete the structure with 3 ft of fill. The initial fill also included a PVC liner over the tunnel to assure a waterproof system.
Once the facility opened in December 2017, Toyota and Visteon Corp. were the first to utilize the track. Toyota Research Institute engineers conducted orientation and driver training while Visteon tested its DriveCore technology, an autonomous highway driving system, during a snowstorm. Tests can occur during all four seasons, in various weather conditions, at night, or during the day. Future plans include developing technology to allow cars to communicate with other cars and with roadway infrastructure. Other companies, such as Ford Motor Co., Hyundai, and AT&T, also plan to utilize the test track in the near future.
"We are excited to be open for testing and to have our founders already leveraging the assets of this facility," said John Maddox, CEO with ACM. "We have been moving rapidly, and along with good input from our founders, a great deal of work has gone into developing this site. Opening our doors is just the beginning as we continue to develop ACM into a global hub for CAV and future mobility technologies to put self-driving cars on America's roads safely."
Funding for the project was provided by the Michigan Strategic Fund ($15 million) and the State of Michigan ($20 million). Other founding donors include: Ford, Toyota, Hyundai, Visteon, and AT&T. In January 2018, the center announced it had secured a $2 million private investment from Subaru of America, Inc.
“It has been an exciting year for ACM and we are pleased to start 2018 welcoming Subaru as a sponsor as we continue to solidify ACM as the global destination for testing CAV and mobility technologies,” added Maddox. “Thanks to the support and hard work from our founders and sponsors, automotive technology leaders and the state of Michigan, ACM is on the leading edge of getting self-driving cars safely on the world’s highways and roads.”
As new autonomous vehicle platforms and systems are developed, ACM will expand as needed to meet the founding automaker's future needs. $110 million of the $135 million budget has already been secured for the first two phases of future expansions, with construction scheduled to begin in spring 2018. The expansion will include an urban driving environment, ACM headquarters, and a tech park.
ACM is a joint initiative with the state of Michigan, founded in partnership with the Michigan Department of Transportation (MDOT), the Michigan Economic Development Corporation (MEDC), the University of Michigan, Business Leaders for Michigan, and Ann Arbor SPARK. In October 2017, ACM signed a memorandum of understanding with 15 colleges and universities in Michigan to collaborate on creating educational pathways to train and prepare students to support automated vehicle testing and implementation.
ACM is also part of PlanetM, a collaboration representing Michigan’s unique and vast ecosystem by connecting resources and opportunities for its members. Made up of private industry, government, and institutions of higher learning, PlanetM partners share the common goal of leading the development of smart solutions that will change the way people and goods are transported across all modes of transportation.
Lastly, the collaboration between ACM, Mannik & Smith, and Contech resulted in the successful utilization of the BridgeCor tunnel.
Technical Description:
• BridgeCor
® Structural Plate
• Span: 49-ft. 6-in.
• Rise: 24-ft.
• Length: 702 ft.
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