Tandem lift for gantry crane

20 November 2017 by Sotiris Kanaris

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A Terex AC 700 and a Demag AC 500-8 supplied by Wiesbauer were used to lift a 45m-long gantry crane at Gebr. Lotter’s mild steel yard in Ludwigsburg, Germany. In a tandem lift, the two cranes lifted the load to the pre-planned assembly location.

 

Due to the tight space conditions, there was only one single spot at the premises where the two cranes could be positioned next to each other for the tandem lift – and for one of the cranes, this meant being at a significant distance from the assembly position for the gantry crane.

“This meant that we had to perform the lift working with high radii,” said Marco Wilhelm who was in charge of planning the lift at Wiesbauer.

The Wiesbauer team planned for the AC 700 to deal with the toughest part, as it would have to span the entire width of the yard, all the way to the rear gantry crane rail axis, with its load side. The maximum radius required for this was 42m, while the maximum radius required for the AC 500-8 crane was 24m.

In order to ensure that they would be able to lift the 45m-long, 15m-tall, 58t girder, the two cranes were configured with a main boom and 140t of counterweight.

Once set up this way, they were ready to lift the load to a height of 15m and rely on their high precision to swing it to the exact position that had been planned for it. There, an additional telescopic crane was used to fully assemble the gantry crane while the latter’s girder remained suspended in the air. This meant that the Terex Demag duo had to keep the load perfectly in place for several hours.