In 2007, a Bechtel joint venture with Kiewit Pacific completed the longest U.S. suspension bridge built in four decades—the new Tacoma Narrows Bridge. As the third bridge to cross Puget Sound from Tacoma to Gig Harbor, the new span shares traffic with its adjacent namesake, which was completed following the spectacular collapse of the first Tacoma Narrows Bridge in 1940.
The last undulating moments of that aerodynamically unstable prewar bridge—Galloping Gertie—were caught on newsreel footage and helped forever change the way suspension bridges are built. The new bridge can withstand winds two-and-a-half times the speed of those that toppled Gertie.
The first major phase of construction—the foundations for the towers—began in the summer of 2003, when two giant caissons, each the size of a seven-story building, were towed into place just south of the existing bridge. Over the course of several months, they were slowly filled with concrete and sunk to the narrows floor, 50 yards (46 meters) below the surface. Our project team completed the caissons by June 2004.
Thanks to advances in materials technology, the new towers are made of reinforced concrete, requiring less maintenance than the steel towers of the adjacent bridge.