Model reduction and substructure technique - application to modular shell structures made of ultra high performance concrete

壳结构特别适合建造轻型建筑，因为它们可以建造成相对较薄的尺寸。壳也可以在自然界中找到，因此在仿生学的背景下，建筑可以面向自然界的例子。在钢筋混凝土建筑中，钢筋壳的使用已经很长时间了。然而，单壳的建造需要非常高的索具和模板的努力。这就是为什么概念被开发出来的原因，外壳由模块制成，然后在施工现场组装在一起。模块的概念也提供了处理分形结构的可能性。这个想法在这个项目中得到了进一步的发展。研究工作的重点是为此类壳结构的设计和有效的静、动力模拟提供合适的数值方法。这意味着采用已经存在的子结构和模型简化技术。这些必须适应新的使用领域，必须与非线性有限元技术相结合。新的组合方法的主要和在这个现有的研究领域迄今未使用的优势在于可以考虑单个模块的非线性性能，每个模块只有很少的自由度（在3到5个内部自由度的区域）。可以避免对相同形状的不同元素进行重复计算。一方面，可以快速确定不同负载组合下模块的最优配置。另一方面，（超高性能）混凝土的独特非线性行为，也在模块之间的接缝打开后，可以考虑在内。由于预期的剩余承载能力，结构具有较高的延性。这里提到的概念提供了由平面多边形模块组成的弯曲壳结构的组成。模块之间的连接区域应与其平面成直角。为了在两个模块之间的连接中实现弯曲壳的必要角度，正在使用连接部件。这些被形成为不同角度的半成品零件，并根据模块的边缘分别切割长度。模块的连接是通过中心无粘结预应力实现的。这种连接技术允许在不破坏外壳的情况下拆除，因此可以进一步使用这些元素。由于后一个原因，这种建筑形式特别适用于临时性建筑。已经使用的部件可以用来建立一个完全不同的形状的新壳。

Shell structures are especially suited for the construction of light-weight buildings, since they can be constructed to have relatively thin dimensions. Shells can be also found in nature, so that in the context of bionics the construction can be oriented to examples in nature. In reinforced concrete construction the use of reinforced shells has been common for a long time. The construction of monolithical shells, however, needs a very high effort for rigging and formwork. This is the reason why concepts have been developed where shells are made out of modules which are then put together on the construction site. This concept of modules also offers the possibility to work with fractal structures. This idea is picked up and developed further in this project. The main focus of the research work lies in the supply of suitable numerical methods for the design and efficient static and dynamic simulation of such shell structures. This means to employ already existing substructure and model reduction techniques. These have to be adapted to the new field of use and have to be connected with non-linear finite element technologies. The main and in this existing research field so far unused advantage of the new combination of methods lies in the possibility to take into consideration the non-linear performance of the single modules with only very few (in the area of 3 to 5 inner) degrees-of-freedom per module. Redundant calculations for different elements of the same shape can be avoided. On the one hand optimal configurations of modules for different load combinations can be determined quickly. On the other hand the distinctive non-linear behavior of the (ultra high performance) concrete, also after the opening of the joints between the modules, can be taken into account. Due to the expected residual load bearing capacity the structures have high ductility. The concept mentioned here provides the composition of curved shell structures made of plane polygonal modules. The connecting zones between the modules shall be at right angle to their plane. In order to achieve the necessary angles for curved shells in the connection between two modules, joining parts are being used. These are being formed as semi-manufactured parts for different angles and are cut in length respective to the edges of the modules. The connection of the modules is achieved by centered unbonded prestressing . This joining technology allows the dismantling without destruction of the shells and therefore a further use of the elements. For the latter reason this form of construction can be used especially for temporal buildings. The already used parts can be used to build new shells with an entirely different shape.