Since the crane had to move under load, which weighed over 400t, the company decided to use its Demag CC 3800-1 crawler crane. The lift, done on behalf of Metzingen-based construction company Gottlob Brodbeck, had to be done in a very tight timeframe.
“Due to the fact that we had only 100 hours to tear down the old bridge and lift the new one into place, it was absolutely crucial not to have any delays in the lift whatsoever,” said Marco Wilhelm, project leader at Wiesbauer.
The crane was transported to the worksite on lowbed trailers and trucks in about three days. It took the four-person Wiesbauer team four days to set it up with the help of an assembly crane and a telehandler—a routine job for the experienced team, which had no problem putting together the SSL_1 configuration with a 54m boom length, 225t counterweight, 50t central ballast, and 325t Superlift ballast.
Rigging the load, however, proved to be a lot more complex: “Due to the concrete element’s shape, the four attachment points had to be set up asymmetrically. In order to be able to use equally long wire ropes, we made the steel eyes used to attach the clevises with different lengths to compensate as necessary, and this enabled us to implement a symmetrical rigging geometry,” Wilhelm explained.
The team carried out a trial lift on the day before the job in order to check how they would be working with the load.
The CC 3800-1 lifted the bridge element, with its gross load weight of 403t, from the pre-assembly area at a radius of 19m and to a height of 4m first. After this, the crane swung the load 90° and moved it 6m forward towards the railroad line. There, the crane operator aligned the element with another swing and finally placed the component exactly in the required final position.