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

壳体结构特别适合于建造轻质建筑，因为它们可以建造成相对较薄的尺寸。贝壳也可以在自然界中找到，因此在仿生学的背景下，这种构造可以指向自然界中的例子。在钢筋混凝土建筑中，钢筋网壳的使用由来已久。然而，建造整体壳体需要非常高的索具和模板。这就是为什么概念已经被开发出来，其中贝壳是由模块制成的，然后在施工现场组装在一起。这个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继承和发展。研究工作的重点在于为此类网壳结构的设计提供合适的数值方法，并进行有效的静力和动力仿真。这意味着使用已经存在的子结构和模型简化技术。这些都必须适应新的使用领域，并必须与非线性有限元技术相联系。在这一现有的研究领域中，新方法组合的主要和迄今尚未使用的优点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(内部)自由度(在3到5个范围内)。可以避免对相同形状的不同元素进行冗余计算。一方面，可以快速确定不同负载组合下模块的最佳配置。另一方面，(超高性能)混凝土的独特的非线性行为，也是在模块之间的接缝打开之后，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组成的曲壳结构。模块之间的连接区应与其平面成直角。为了在两个模块之间的连接中实现曲线壳所需的角度，使用了连接件。这些部件被形成为不同角度的半成品，并根据模块的边缘在长度上进行切割。各模块的连接通过中心无粘结预应力实现。这种连接技术可以在不破坏外壳的情况下拆卸，从而进一步使用元素。出于后一种原因，这种建筑形式可以特别用于临时建筑。已经使用过的部件可以用来建造具有完全不同形状的新壳。

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.