A Colombian contractor is using a single Liebherr 71 EC-B 5 flat-top crane in a free-standing climbing format to simultaneously erect four residential tower blocks at the Torres del Sol development in Bogota.
Three of the blocks are directly adjacent and linked, while the fourth is set at 90° to the others, thereby forming two sides of a rectangle with all areas of the buildings accessible by the 50m boom of the crane.
Torres del Sol is being built by Coninsa Ramon H Inc, a company formed in 1999 by the merger of two long-established construction companies, Coninsa and Ramon H Lodono. 
The 71 EC-B 5 is being supplied on a 15-month rental basis by Liebherr’s exclusive distributor for Colombia, MCS Colgruas.
Project manager at Torres del Sol is William Mora, who says that the towers are each 17 storeys in height and feature apartments in the 70, 80 and 89 sq.-m size configurations.
“The crane has a 50m boom and with a 5-tonne maximum lift is able to supply all the lifting needs for the four blocks from this one position,” he says.
According to Mora, the unit is mounted directly next to a busy side road that leads into the development, and is right next door to a shopping centre. “We have mounted the crane at the front of the building, and at first we had it on the standard height of 37m,” he says. “As the blocks grew in height, simultaneously, we moved the height of the crane upwards to its final level of 50m.”
Liebherr’s specifications met all the safety regulations, Mora says, and the project has progressed smoothly. “We have hired the crane for the duration of our contract, and with the project very nearly completed, we are on schedule,” he adds.
The 71 EC-B 5 like all Liebherr EC-B flat-top cranes, is based on a modular design concept, so that the tower system is compatible with any other crane in this range.The 71 EC-B 5 with a modular head that makes it fast and easy to erect and dismantle, an advantage in a busy or congested urban area.
