Features/Benefits Provided:   Custom-Engineered End Trucks Navigate Longitudinal Slope of 3.43% Adjustable Span Same Crane Adapted & Used for Different Applications

Application Overview
Standard cranes and “off the shelf” material handling equipment will not suffice for bridge work. One must consider weather conditions, power source, limited area, and inclines among other things. A large general contractor turned to North American Industries (NAI) to design a customized gantry crane that would take into consideration all these factors and allow the contractor to rebuild bridges on the Ohio River.

The 7.5 US ton crane was recently constructed and installed by NAI. All bracing from legs to girder was outboard. The gantry legs were designed so that loads could pass through the legs of the crane.

The end trucks are designed to negotiate a longitudinal slope of 3.43% along the bridges. As the hoist moves across the length of the cross girder, the trolley can navigate a cross slope of 4%. The material handling system is powered by an onboard diesel generator and has an adjustable span so that it can be used for different bridge work projects. The gantry (including the bracing) was designed to completely bolt together because it would be moved several times. The crane meets NEMA 4 specifications to endure outdoor weather.

Motors, controls, and open gears are covered, and heaters in the motors and panels eliminate any chance of condensation buildup. The crane is also equipped with emergency brakes that are capable of stopping the fully loaded crane traveling at full speed with 50 mph winds. In the past, towers and crawlers would be used for bridge, subway, and tunnel construction, but contractors are increasingly turning to gantry cranes.

Gantry cranes are ideal for heavy construction projects such as this one. They can operate in a limited amount of space and are cost competitive because they can be reconfigured for the next project.

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80 Holton St.
Woburn, MA, 01801
Phone: (800)847-8470 or (781)897-4100 Fax: (781)729-3343
info@naicranes.com
www.naicranes.com