Sandwich constructions with thin folded and curved concrete layers

夹层结构的混凝土层由非腐蚀性高性能材料制成，根据形式遵循力，促进轻质，可持续和整体建筑结构。世纪初建造的薄壳结构属于单功能构件。然而，关于承载能力和细长度的高潜力是显而易见的。壳体结构和夹层结构的结合产生了结构构件，这些构件具有资源消耗少、高能效和模块化以及隔音和防火等特点。在第一个资助期内，研究了建立预张拉折板夹层结构的基本原理。除了开发可重复使用的CFRP锚固件外，还对高性能混凝土中预张CFRP的粘结性能进行了表征，并确定了无裂纹传输区的最小厚度。在拉伸和剪切载荷下的组件测试中，可以显示出在包装中发泡的芯层的高潜力。第一个试验在短时间内对预张紧折叠板和直中心线折叠板夹层梁进行了加载，试验结果表明该设计具有很高的性能。第二个资助期的目标是开发新型夹层系统，该系统由高强度、耐腐蚀材料制成，具有折叠和双弯曲混凝土层。通过部件和结构构件的数值建模和实验测试，将根据形状随力变化的材料特定承载作用，对壳体几何形状和材料组合（UHPC、TRC、PUR、连接装置、CFRP预拉伸）进行研究。根据不同的承载机理，推导了HP型折板夹层梁和双曲夹层壳的工程模型。该模型描述了由于预拉伸，泡沫芯和混凝土壳之间的粘结以及在短时间和长时间加载条件下的双轴材料性能的承载行为。

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.