Still Used Today, Mass.' Hoosac Tunnel Stands as Testament to 1800s Ingenuity

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Nevada's Second-Longest Bridge Takes Shape in Northwest Las Vegas

Wed November 20, 2019 - West Edition #24
Nevada DOT




The Nevada Department of Transportation (NDOT) reports that construction on the state's second longest bridge has reached its midway completion point. The 2,635-ft.-long flyover will connect northbound U.S. Highway 95 to the westbound 215 Beltway in northwest Las Vegas. It's part of the larger $73 million Centennial Bowl interchange project that broke ground in January. Las Vegas Paving is the general contractor.

The 75-ft.-tall by 39-ft.-wide bridge is a box girder type structure constructed from cast-in-place concrete. It will measure the equivalent of seven football fields laid end-to-end, providing two travel lanes in each direction linking north-to-west freeway traffic. The bridge uses 14,270 cu. yds. of concrete, or enough to fill six Olympic-sized swimming pools, delivered by 1,500 cement mixer truck trips.

The bridge concrete is pumped into forms, which act like cake pans, then cured to achieve maximum structural strength. It's structurally supported by rebar, with post-tensioned steel cables that act as tendons. The driving surface, meanwhile, is the icing on the cake.

The project additionally entails building a second, smaller interchange bridge, measuring 60-ft.-tall by 31 ft. wide, that links the eastbound 215 Beltway with southbound U.S. Highway 95. The south-to-east flyover will be 1,655 ft. long or roughly the same distance as the Sears Tower laid on its side.

The project's two massive flyovers are going up simultaneously, crisscrossing in midair. The dual bridges sit atop a foundation of 60 drilled piles up to 80 ft. deep and 10 ft. in diameter. The flyovers are supported by 1,800 lineal ft. of falsework and 5.2 million lbs. of reinforcing steel, or enough to forge 50,000 suits of armor. The massive undertaking, employing up to 150 tradesmen, is scheduled to finish in November 2020.

Flyover ramps enable direct freeway-to-freeway connections while still maintaining highway travel speeds for greater efficiency and safety. Also, the structures require little right-of-way and eliminates the current stop-and-go surface street travel currently needed when navigating the interchange.