Gallery: Hoover Dam Bridge

Strong stomachs and serious suspension

Hoover Dam Bridge Image 1
Temperatures upward of 115°F, winds capable of felling cranes, an 890-foot drop below: "Inhospitable" doesn't begin to describe conditions at the Colorado River's new Mike O'Callaghan-Pat Tillman Memorial Bridge.
Hoover Dam Bridge Image 2
A 1,900-foot span designed to divert traffic from the narrow, switchback-laden road across the Hoover Dam, it will be the longest concrete arch bridge in the Western Hemisphere when it opens next fall, with 106 segments of ultra-high-strength concrete forming a twin-rib arch.
Hoover Dam Bridge Image 3
Workers scaled the canyon's walls, digging notches for concrete foundation columns and installing other heavy bridge parts.
Hoover Dam Bridge Image 4
To construct the 1,060-foot-long arch, they cast 24 feet of concrete at a time, while a separate, temporary cable-stayed bridge held up the unfinished ends until the gap was closed this year.
Hoover Dam Bridge Image 5
A head-on view of the construction shows the twin-rib arch of this concrete bridge.
Hoover Dam Bridge Image 6
Until the gap was closed this year, large cables from a separate temporary bridge supported the concrete.
Hoover Dam Bridge Image 7
A rendition of the bridge during construction at night.
Hoover Dam Bridge Image 8
A view from above of the bridge during construction.