Elliptical design demands inventive Schöck thermal break solution

The recently completed Kameha Grand in Bonn is already recognised as one of the world’s exceptional new luxury hotels. It nestles on the banks of the Rhine to the south east of Bonn and features 253 rooms, of which 63 are suites. Winner of the 2010 MIPM award for Hotels and Tourism, which is presented for outstanding real estate projects worldwide, the Kameha Grand was designed by architect Karl-Heinz Schommer Bonner who explains: “The most noticeable architectural feature of the hotel is its transparency. The view from the entrance looks through the lobby, the atrium and Kameha Dome space right to the riverbank. Guestrooms are arranged on only three sides of the atrium, the fourth being glazed with views to the river“.

The unique elliptical section design did however make serious demands on the requirement for protection against thermal bridging.  The architect discussed the issue with Schöck, the European specialists in thermal bridging solutions and it was agreed that a combination of three product variants would meet the requirement.

The outer concrete arches on the roof and facade of the building cantilever 1.30m on each side and this, combined with the subtle design of the facade, meant that it was not possible to use a standard thermal break solution. To minimise any thermal bridging problems along the two outer arcs an inventive solution had to be found by the Schöck design team. This was achieved by dividing the projecting element of the framework into a number of sections and using the appropriate Isokorb® for the required forces. At the ground floor type Q is used, with type D being installed higher up the structure, followed by type K on the top floor. Because of the arch profile, the type D Isokorb was cut and installed at 90 degrees and run under the curved edge of the roof emergency exits, providing F90 fire protection.

The three isokorb® variants are designed for concrete-to–concrete cantilever connections and offer outstanding thermal insulation properties, dramatically reducing thermal energy loss in connective areas by guaranteeing the homogeneity of the thermal envelope between cantilever structures and the internal slab. They also transfer load and maintain full structural integrity, while at the same time enabling inner surface area temperatures to remain well in excess of those likely to cause mould formation and condensation.

For further information about services from Schöck, or to request a free copy of the Specifiers Handbook contact Schöck Ltd on: tel: 0845 241 3390; fax: 0845 241 3391 email: design@schoeck.co.uk