Sandwich constructions with thin folded and curved concrete layers

点击翻译按钮获取中文摘要

Sandwich constructions with concrete layers made of non-corrosive high performance materials, facilitate light, sustainable and integral building structures according to form follows force. Shell structures built in the early 20th century belong to the group of mono-functional construction members. Nevertheless a high potential regarding load carrying capacity and slenderness is obvious. The combination of shell structures and sandwich constructions leads to structural members, which exhibit coexisting features, namely small consumption of resources, high energy efficiency and modularity as well as sound insulation and fire protection.In the first funding period the basic principles for the establishment of pre-tensioned folded plate sandwich structures have been investigated. Besides the development of a reusable anchorage for CFRP, the bond behaviour of pre-tensioned CFRP in high performance concrete was characterised and a minimum thickness for a crack-free transmission zone determined. In component tests under tension and shear loading, a high potential of core layers, foamed in pack could be shown. First tests under short-time loading on pre-tensioned folded plates and folded plate sandwich girders with straight centreline already showed a high capability of this design.The goal of the second funding period is the development of novel sandwich systems made of high strength, non-corrosive materials with folded and doubly-curved concrete layers. With numerical modelling and experimental testing of components and structural members, the shell geometry and material combinations (UHPC, TRC, PUR, connecting devices, CFRP pre-tensioning) are to be investigated regarding a material specific load carrying action according to form follows force. On the basis of a characterisation of the different load carrying mechanisms, an engineering model for folded plate sandwich girders and doubly-curved sandwich shells with HP shape will be derived. The model describes the load carrying behaviour due to pre-tensioning, bond between core foam and concrete shells as well as biaxial material performance under short-time and long-time loading conditions.