Sandwich constructions with thin folded and curved concrete layers

夹层结构的混凝土层由无腐蚀性高性能材料制成，促进轻，可持续和整体的建筑结构，根据形式服从力。20世纪初建造的壳结构建筑属于单功能建筑构件。然而，在承载能力和长细度方面的高潜力是显而易见的。壳结构与夹层结构相结合形成的构件，具有资源消耗少、能效高、模块化强、隔声防火等特点。在第一个资助期，研究了建立预张折板夹层结构的基本原理。除了开发可重复使用的碳纤维布锚固物外，还对高性能混凝土中预应力碳纤维布的粘结行为进行了表征，并确定了无裂纹传输区的最小厚度。在拉伸和剪切载荷作用下的构件试验中，可以看出堆芯泡沫层具有很高的潜力。在短时间荷载作用下对预张折板和折板夹芯梁进行的初步试验表明，该设计具有较高的性能。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、无腐蚀性材料制成，具有折叠和双弯曲的混凝土层。通过对构件和结构构件的数值模拟和实验测试，对壳体几何形状和材料组合（UHPC， TRC， PUR，连接装置，CFRP预张紧）进行了研究，根据形式跟随力对材料的特定载荷承载作用进行了研究。在分析不同承载机制的基础上，推导了HP型折叠板夹层梁和双弯夹层壳的工程模型。该模型描述了在短时间和长时间加载条件下，由于预张拉、核心泡沫和混凝土壳之间的粘结以及双轴材料性能而产生的承载行为。

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.