InterCity Hotel

The IntercityHotel in Hannover-Ost is a very special hotel: The layout is pentagonal; there is only one right angle. That is a challenge in itself; but the greater challenge was the desire for different use concepts on the various floors. If possible, in order to achieve the highest possible level of variability, columns, which would have limited the room division, needed to be avoided.

The plan for the IntercityHotel was to put a reception area and a bar on the ground floor, a restaurant on the first floor and conference rooms on the second floor; only hotel rooms were required from the fourth floor up, and the floor plans needed to be identical. Therefore, it was possible to use supporting columns for the upper floors, but on the lower floors, they would have been a bother.

Thanks to Cobiax, floor areas of 8 m could be spanned, using a one-field construction method. (In other cases, the technology even enables span widths of up to 20 m.) The storeys can be used variably, and even on the lower floors, there are no supporting columns that limit the possibilities.

Besides the desired variability in the utilization options for the various floors, weight factors were decisive for the choice of the Cobiax voided flat plate slab systems: Had solid concrete slabs been used, considerably more columns would have been required for the drilled pile foundations.

The Cobiax slabs are so light, that ten of the 18 m bored piles were unnecessary – thanks to the voided slab technology, a weight reduction of around 15,000 kN was achieved for the entire building.

The economic and aesthetic reasons for the use of Cobiax are compelling; but the accompanying aspects are also very pleasing: the depth of the slabs was reduced to 30 cm (compared to the usual 32 cm) and due to the reduced concrete requirements (- 403 m³), around 85 tons less CO₂ was emitted.