Dive Brief:
- Where the Interstate 75 bridge crosses the Caloosahatchee River in Florida, two 84-foot-wide gantry cranes on rubber tires were the way to handle materials to add interior lanes, but GPS is the way to handle the cranes.
- de Moya Group and Leware Construction Co, the contractors for the project, tried human-guided steering but had a very difficult time keeping loads under control.
- Along with adding GPS gear to guide the cranes through the bridge section's 1-degree curve and up and down its 3.5% slope, the job required rigging top let the cranes deliver materials as far as 50 feet below the bridge deck.
Dive Insight:
Mi-Jack Products—the equipment suppliers for the project— said the cranes' 84-foot clear span is a good 20 feet longer than is usual for the kind of project involve. The GPS is also used to deliver or retrieve materials for areas located more than 50 feet below the work deck, and cost $750,000 each.