The Left Coast Lifter hoisted the first girder segment into place at the $3.9 billion Tappan Zee Bridge project in New York.
The piece -- 400 ft long, 1,100 tons and made of three prefabricated, curved steel girders -- was placed between two concrete piers, signaling the start of the next construction phase.
The Left Coast Lift cannot swivel, so the barge that supported it had to be turned around to allow the triple girder to close in on the piers.
After three and a half hours of slowly moving in midair, the horizontal assembly was dropped in place with the aid of eight ironworkers, four crane operators and a global positioning system that ensured the joining together was pinpoint accurate.
Eventually, 31 miles of girders will be installed to support the 3.1-mile-long deck.