From Jointing Systems to Light-Weight Structures: Hybrid, dry-fit beam, surface and spatial structures made of UHPFRC

作为正在进行的SPP 1542的一部分，申请人正在进行子项目：开发用于几何复杂表面和UHPC梁元件的新型连接系统。调查的重点是开发用于传递压缩力、弯曲力和剪切力的UHPFRC薄壁构件的干配合连接系统。主要方法是通过提高连接区域的精度和几何复杂性来实现高机械效率。除了精确的装配外，组件还通过集成的预应力筋元件进行轴向预应力。目前正在为以下UHPFRC构件开发新型连接系统：用于传递压缩力的轴向加载和干配合薄壁管，用于引导梁结构中的力的薄壁管弯曲刚度节点元件，以及用于分段壳体构件精确装配的线形干配合连接系统。在第一个研究期结束时，将实现第一次供资中确定的目标。到目前为止，研究结果已经发表了好几次。现在，后续应用的目的是将先前开发的UHPFRC构件的新连接原理转移到强大的轻质梁、表面和空间结构中。目标是通过将单个模块化梁和壳元件智能耦合到混合、协作的支撑元件和系统中来增加结构部件和系统的承载能力。通过组合与抗剪切、平坦或弯曲表面元件相关联的干配合杆，可以实现主要从弯曲承载结构到优化壳体的各种相关建筑结构类型。项目第一阶段的先决条件仍然有效：使用UHPFRC来提高抗拉性和开裂后的性能，通过预应力实现干配合连接和有效的材料利用。由于在本研究项目中，并非所有可能的梁和壳的几何多样性组合都可以进行研究，因此从研究项目的可能支撑元件组合中选择了三个相关的施工实践案例：将梁单元和壳单元组合成单轴预应力梁单元，将梁和壳单元组合成正交双向预应力曲面结构，将梁和壳单元组合成曲面空间结构。根据几何约束，所得到的混合结构系统和三维空间中的单元可以作为梁和表面作为主要弯曲加载部件或作为膜结构。

As part of the ongoing SPP1542 the applicants are working on the subproject: development of novel jointing systems for geometrically complex surfaces and beam elements made of UHPC. Focus of the investigation is the development of dry fit jointing systems for thin UHPFRC components for the transmission of compression, bending and shear forces. The main approach is to achieve a high mechanical efficiency through increased precision and geometric complexity in the jointing area. Besides precise fitting the components are axially prestressed by integrated tendon elements. The novel jointing systems are being developed for the following UHPFRC components: Axial loaded and dry fit thin walled pipes for the transmission of compressive forces, bending stiffness node elements of thin walled tubes for guiding forces in beam structures, as well as line shaped dry fit jointing systems for accurate assemble of segmented shell components. The objectives identified in the first funding are reached by the end of the first research-period. The results so far have been published several times. The aim of the subsequent application is now to transfer the previously developed new jointing principles for UHPFRC components into powerful light weight beam, surface and spatial structures. The goal is to increase the load bearing capacity of structural components and systems by intelligent coupling of individual modular beam and shell elements into hybrid, cooperating supporting elements and systems. By combining dry fit rods associated with shear resistant, flat or curved surface elements a variety of relevant building structure types can be realized mainly from the bending load bearing structures towards optimized shells. The preconditions of the first project phase remain valid: Using UHPFRC to improve tension resistance and post cracking behaviour, dry fit jointing and efficient material utilization through prestressing. Since in this research project not all possible combinations of beams and shells in their geometric diversity can be investigated, exemplified three relevant construction practice cases from the possible support element combinations for the research program are selected: combination of beam and shell elements into a uniaxial prestressed girder element, combination of beam and shell elements into an orthogonal biaxial prestressed surface structure and combination of beam and shell elements into curved spatial structures. Depending on the geometric constraints the resulting hybrid structural systems and elements in three dimensional space can work as beams and surfaces as mainly bending loaded component or function as membrane structure.