Heidebroek-Bau der Technischen Universität Dresden - Ertüchtigung und Instandsetzung des vorgespannten Faltwerkdachs

Heidebroek-Bau at the Dresden University of Technology - Improvement and repair of the prestressed folded-plate roof.

The roof construction of the Heidebroek-Bau, erected as an experimental building, is a folded-plate construction comprising tied precast segments of reinforced concrete. Given the inadequacies in the design and the dampness which had penetrated the structure over a period of many years as a result of the desolate condition of the seals, it was to be assumed that the prestressing members already displayed corrosion and that the structural safety of the roof was thus to be questioned. Initially secured by way of temporary staging towers as auxiliary support, the roof construction was subsequently strengthened and repaired. The building work was accomplished without interrupting the use of the research hall by the Dresden University of Technology. To ensure a sufficient load-bearing strength should individual prestressing members fail, and to eliminate the risk of a sudden total failure with progressive collapse of the folded-plate construction, steel lamellae were attached to the inner surface of the roof and anchored at the ends of the folds. The dimensioning of the lamellae, including their anchoring and verification of the existing roof construction, took into account all potential influences specified by the applicable technical standards. This paper discusses the concept for improvement of the supporting structure and the corresponding differentiated verification of stability on the basis of four essential critical states, and provides an overview of key aspects of the tender process, execution of the improvement work and monitoring of the implemented strengthening and repair measures.