ALL Erection & Crane Rental, flagship yard of the ALL Family of Companies, provided heavy lift equipment for a series of lifts, primarily involving the large trusses used to construct the new bridge.
The bridge’s structural support is provided by Pratt trusses, assembled on site by Kokosing Construction, the project’s general contractor. Pratt trusses are triangle-shaped, with diagonal supports that slope toward the center of the bridge (they were introduced in 1844 as an effective way to cover long spans of 250 feet or more; this bridge is 300 feet).
The most recent lift work required only a single crane after an initial run of dual picks. For the single-crane picks, ALL used a 770-ton Liebherr LTM 1650-8.1 all terrain crane with 171 feet of main boom in the T5Y configuration, meaning Y guying was added to boost lift capacity. On one action-packed workday, the 1650, set up on a flat bank of the river below, lifted two Pratt trusses, set a half-dozen 50-foot floor beams, and several roof trusses.
Liebherr’s VarioBallast® was key to setting so many large pieces so efficiently. It allows the ballast radius to be infinitely adjusted using a hydraulic slewing mechanism. “The operator can constantly transfer and adjust the counterweights depending on the weights of each piece and the radius required for each pick,” said Rick Cope, project superintendent for Kokosing. “Seeing what these large specialty cranes are capable of is impressive.”
