Oakland, Calif. — The Tom Lantos Tunnels at Devil’s Slide, designed by HNTB Corporation, already have been honored with 15 industry awards, and more are anticipated. Two of the most recent honors are Underground Construction Association Project of the Year and American Public Works Association’s Public Works Projects of the Year.
The UCA award was presented in late June at the 2014 North American Tunneling Conference in Los Angeles. The APWA award will be presented in August at the 2014 International Public Works Congress and Exposition in Toronto.
The $430 million Tom Lantos Tunnels project — located in San Mateo County, Calif. — represents the first road tunnels constructed by Caltrans in more than 50 years. And, as they officially opened to traffic on March 26, 2013, are now the longest road tunnels in California. The project replaced an infamous coastal stretch of California’s State Route 1, which was subject to lengthy closures from slipouts and rockslides, high maintenance costs and risk of permanent failure.
HNTB worked closely with Caltrans to fully explore alternative designs and construction methods for the twin tunnels. Constructed beneath San Pedro Mountain using the New Austrian Tunneling Method, each one is 29 feet, 6 inches wide by 22 feet, 4 inches high and 4,265 feet long. They are connected by 10 emergency cross passages. The project lies along the active San Andreas Fault, with four inactive faults crossing the tunnels. Ten different rock masses were encountered along the tunnel alignment. Despite challenging technical and environmental constraints, HNTB successfully completed the project to the client’s satisfaction.
“To be recognized with these international, national, regional and local awards is a tremendous honor for Caltrans, HNTB and all the firms that provided engineering services on Devil’s Slide,” said Yung-Nien Wang, PE, HNTB project manager and structural lead in Southern California. “Our first priority was to design tunnels that truly meet the needs of the communities they serve. The prestigious awards the project has earned are an added bonus.”
Other awards accrued by the Tom Lantos Tunnels include: