In 2000, Koch Skanska, along with joint-venture partner American Bridge, was awarded a $144 million project to replace the decks of the Triborough Bridge on the suspension sections over the East River. The bridge spans three boroughs and carries over 200,000 vehicles per day. Because of the heavy amount of vehicular traffic on this bridge daily, the client required the joint-venture team keep seven lanes of the bridge open during the process of replacing the decks and beams.  This required the team to come up with an alternate method of replacing the decking since such work is usually done by closing traffic lanes and using cranes to remove old sections and replace them.

In order to facilitate the timely deck removal, the team decided to use overhead double-girder bridge cranes, which spanned the entire 98 ft. of roadway. Had traditional methods been used, it would have been difficult to avoid lane closures on the structure. The team removed all of the existing road surface from the bridge, one lane at a time and replaced it with new steel deck sections.

This was the first time that such cranes had been used to replace suspension bridge sections in the United States. Even more impressive, all of the work was done throughout normal working hours literally feet away from thousands of vehicles. The crane supplier, Demag, equipped the cranes with a safety feature that would automatically engage wind locks and secure the cranes in place in the event that winds exceeded 25 mph.

Additionally, the cranes were designed to be erected in a one-time operation, which took place at night. Each crane was installed in a three-lift operation, each lift taking only seven minutes. Two of the cranes were installed simultaneously. 

A total of 553 precast deck units will be used on the project. Typical units are 10 ft. wide and 35 ft. to 38 ft. long. Each unit is cast with steel floor beams and connecting diaphragms in place and are over 8 in. thick.