Bragg Liebherr LR 1300 Helps Build Transit Network at Phoenix Airport

Enlarge Image Liebherr LR 1300 Crane

October 14, 2010 — The Phoenix, Ariz., division Bragg Crane Service, Long Beach, Calif., is managing the construction of the Sky Train transit network at the Phoenix Sky Harbor International Airport. Bragg is working for Pro Steel Erectors, Kingsbury, Texas, and using a Liebherr LR 1300 lattice-boom crawler crane to lift and install more than 1,100 metric tonnes (1,200 tons) of steel.

The LR 1300 was used with 68 meters (223 feet) of main boom, 124 tonnes (273,400 pounds) of counterweight and 57 tonnes (125,700 pounds) of car body weight. A 28-meter (92-foot) derrick was rigged with a further 75 tonnes (165,300 pounds) on a suspended counterweight tray to make the heavy lifts at a 46-meters (150-foot) radius.

Bragg had to address specific issues in order to operate the crane within 30 meters (100 feet) of airplanes. Boom height, working hours, security, and underground tunnels were a few of the obstacles addressed prior to the mobilization of the equipment. Bragg used rubber conveyor belt sections for matting, as wood chips can present a hazard to airplane engines. This helped protect the 600-millimeter (24-inch) thick concrete, and eliminated the risk of loose particles infecting the jet engines. Another benefit of the matting solution was that it could be quickly rolled out at the beginning and rolled up at the end of each shift.

 

To enable the airport to keep more gates open during the day, Bragg worked only at night, from 10 p.m. to 6 a.m.

 

Configuring the crane with the derrick and counterweight tray allowed navigation of underground tunnels and provided more flexibility: The tray was used for heavy lifts and disconnected to handle smaller lifts with more efficiency.

 

The Liebherr LR 1300 is designed to tackle the heaviest-duty lifting applications. It has a 600-hp engine. It offers a maximum line pull of 33,000 pounds when working with the top layer of rope on the drum and 47,400 pounds on the first layer.

 

Lifting operations are streamlined by the LR 1300’s ability to simultaneously boom out and luff the jib with a full load on the hook. In addition, the Liebherr Litronic LMI system calculates the load chart in real time, which means that the operator can select any boom angle between 45 and 88 degrees, instead of only the angles specified in the load chart.

 

In a separate section of the project, Bragg is also erecting 131 precast concrete girders in two phases. In the first phase, in August, Bragg set 79 girders in nine days. In the second phase, scheduled to be completed in late September,the company was to set 52 girders in a week and a half. These girders span up to 30m (100 feet) and weigh between 40 and 63 tonnes (45 and 70 tons). For these lifts, Bragg uses 300-ton truck cranes.