Parapluie - Realisierung einer ultraschlanken Betonschale durch Aktivierung einer Membrantragwirkung

Parapluie - Fabrication of an Ultra Thin Concrete Shell by Activating Membrane Effects

Parapluie is an ultra thin architectural concrete shell structure for a bus stop shelter designed for a serial production by multiple reuse of the formwork. It is made of ultra-high-performance-concrete that is reinforced with a layered micro mat reinforcement distributed over the whole cross section with zero distance to the outer surfaces. This material composition leads to a highly ductile behavior that is substantiated by the biaxial homogenous cross section layout that allows a linear elastic structural analysis. The aim was to achieve a concrete shell that is as slender and lightweight as possible. By a parametric form finding process a system was developed that is able to transfer the loads of the shell mostly by membrane effects with the analogy of the structure of a sheet of paper. The result is a concrete shell with no steel embedded items and an edge thickness of less than 24 mm.