Sarens uses two Terex AC 700 cranes for a heavy tandem lift

The spreader bar was 13.5m long, 5m wide, 6m high and weighed 145t. It had to be lifted from ground level to a placement height of 32m.

To meet required lifting capacity and working radius, planners went with a 20.5m main boom option, using a 4-m variable adapter to connect the 30m luffing fly jib to the telescopic boom.

In this configuration, each AC 700 crane offers 86.5t capacity at 24m radius, ample capacity to safely lift the 145t spreader bar, said Michael Klein, product marketing manager for Terex and Demag all terrain cranes.

To start the spreader bar lift, the two crane booms worked at a 22m radius, and, as the lift progressed, the boom radius decreased to 17m as the two cranes swiveled the load into position. While placing the spreader bar atop the module, both cranes were operating at a 24m radius, and the two booms were less than a couple of metres apart.

“We considered a number of options from using a single crawler crane to performing a tandem lift using two all terrain cranes”, said Erik Van der Elst, key account manager for Sarens.

The advantage of the single crane option would have been that it required only one crane and crew to be mobilized. However, a crawler crane would require multiple days and more than 20 loads to transport the crane components necessary to configure it to meet 145t lift capacity at a 24m radius.

Even though this option required two cranes to be mobilized, it offered significant time and money savings. The nine-axle AC 700 all terrain crane is quickly driven to the jobsite with its complete 60m main telescoping boom installed, while meeting 12t per axle load limits to reduce the number of loads required for transport.

“We calculated a week’s time savings by using the two Terex all terrain cranes, which represented significant labour and cost savings for our customer,” explained Van der Elst.