Case Study: Composite Construction for FLAT Slabs with Integrated Building Services

About 10 years ago, the idea arose of developing a new flat slab type with integrated building services. The first idea concentrated on a pre-fabricated slab element with a sandwich cross section. The open space (hollow space) between the two outer shells of the sandwich is available for various installation devices. It was also necessary to provide appropriately large openings in the web members joining the two outer shells. In order to provide the necessary strength around the large openings, a steel plate was embedded within the concrete web element. Appropriate composite connecting means were additionally needed to provide bonding capacity to the respective outer shells of the sandwich. In order to satisfy these requirements for the bonding devices, two independent solution proposals were offered. The web members were additionally pre-stressed, in order to reduce the absolute values of the shear stresses. In order to optimize the bonding element, two variants were tested. Different projects were built with the new composite element.