ABSTRACT
In the heart of Berlin an International Solar Center (ISC) has been erected. It gives home to companies working on the field of renewable energy sources. According to its future occupants it has been equipped with an innovative energy concept. To lower the operating energy of the building, concrete core heating of floor slabs and walls as well as energy piles have been installed. Solar cells on the roof have been applicated and natural ventilation is used mostly. The International Solar Center is mainly a concrete structure with a trapeze-shaped atrium sized 60 × 40 × 25 m in its center, which is enclosed by a glass facade supported by a steel structure made up mainly of steel hollow sections. This facade is a very economic and also a very aesthetic part of the building. It spans the atrium of the ISC horizontally and closes the southern side of the building vertically. Basically it is a double layered structure and it uses space trusses where necessary and plane trusses where possible. The use of prestressing for stabilisation causes and the capability of deformations in case of temperature variation of this huge panel have been major issues to be solved by the engineers. It has been one special circumstance of the planning process, that the original architects of the project dropped out so that the structural engineers had to take on responsibility for the conceptual design of the roof. They used their chance to reduce the structure concerning its functional aspects which resulted in a very reduced steel requirement. After an extended preliminary planning process the enclosure was at last realised within a minimum of planning time and erection time reaching complete satisfaction of the client, the involved companies and the structural engineers.
