In the course of 2010 removal works were carried out on the floor of the Grossmarkthalle and the foundation plate for the double office tower was laid. Adjoining the west of the high-rise is the underground staff car park.
The foundation plate of the double office tower is approximately three metres thick. For the reinforcement of the concrete (i.e. the incorporation of steel rods), approximately 4,200 tonnes of steel were required. The casting of the foundation plate needed to be carried out in segments. For each segment, the concrete had to be poured continuously.
The winter of 2010/2011 saw the construction of the two basement levels of the double office tower and the self-contained underground staff car park, which is to the west of the double office tower and will provide approximately 600 spaces over two levels.
Since July 2011 the structural framework of the high-rise has towered over the Grossmarkthalle. The two office towers are growing at the same rate of one storey a week, but in terms of their height, one tower is taller than the other. The top of the structural framework is surrounded by a yellow framework, a shield which allows the formwork and concreting works to continue in bad weather and strong winds, without putting the safety of the workers at risk – even at great heights. The concrete cores of the towers, along with the technical installations and lift shafts, are being erected by means of a mast climbing work platform, while the floors are being constructed using formwork tables. The concrete cores are approximately one to three storeys ahead of the floor construction.
In November 2011 the first of a total of 14 trusses was mounted in the atrium between the two office towers. These steel trusses, together with the interchange platforms, serve to brace the two office towers. They are anchored to large node points; the first joint plate was installed in July 2011. The steel trusses are delivered to the construction site in segments and set down in the atrium area. The segments are then welded together so that each truss consists of two halves.