A method for efficient numerical simulation of masonry under centric/eccentric and/or cyclic biaxial loading derived from near-realistic small-scale experimental tests – Extension, enhancement and validation of the unit-cell-methodology for plain and stre

在第一个资助期间，开发了方法基础，以实际地表征由小块砖制成的砌体的承载行为（在静态单向或循环面内剪切压缩载荷下，这种载荷作用于墙的中间面或偏心面），并在数字上准确地表示它。可以证明，TUM在项目中进一步开发的创新单元测试装置（周期性重复出现的墙元素：砖，轴承，纵向和对接接缝）也可以有效地使用其紧凑的测试样本来系统地分析带有实心砖的小型砌体的复杂损伤行为。在第一个资助阶段，仅针对偏心荷载应用（偏离中心的板支撑），无法完全完成与大型剪力墙试验的验证和比较。因此，在第二个筹资阶段，将进行补充偏心单元和剪力墙试验。此外，除了目前考虑的实体砖外，还将包括小尺寸穿孔砖（中心/偏心）；由于正交各向异性的特性，与实心砖砌体相比，载荷传递和损伤机制有望发生重大变化。此外，还将考虑不同的壁厚和砖的布置，以便能够第一次更精确地评估这些参数对单元格试验的影响。最后，将尝试用小规模试验装置真实地代表加固墙的承载行为。数值模型将进一步发展，以解决其他问题，并根据获得的新实验结果进行验证。计划中的附加光纤传感器（例如砂浆接缝）将为复杂的承载机制提供有价值的附加信息，并丰富和进一步改进仿真模型。在项目成功完成后，将有一个经过科学验证的方法和模拟模型，在单位单元方法的基础上，允许对现有建筑中各种小型砌体（由实心砖或穿孔砖制成，各种类型的砖排列）在单调/周期性，中心或偏心剪切压缩载荷下的承重和破坏行为进行现实预测。因此，与大规模试验（多层剪力墙）相比，可以使用一种更灵活、更强大的工具来真实地评估现有建筑物在各种荷载情景下的行为。此外，到目前为止还没有处理过的配置可以相对容易地添加到整个方法中。

In the first funding period, the methodological basis was developed to realistically characterise the load-bearing behaviour (under static-monodirectional or cyclic in-plane shear-compression-loading, which acts either in the mid-plane of the wall or eccentrically) of masonry made of small-format bricks and to represent it numerically accurately. It could be shown that the innovative unit-cell test setup (periodically recurring elements of a wall: bricks, bearing, longitudinal and butt joints) of TUM, which was further developed in the project, can also be used effectively with its compact test specimens to systematically analyse the complex damage behaviour of a small-format masonry with solid bricks. The validation and comparison with large-scale shear wall tests could not be fully completed in the first funding phase only for the eccentric load application (off-centre slab support). In the second funding phase, therefore, supplementary eccentric unit-cell and shear wall tests are to be carried out. In addition, small-format perforated bricks (centric/eccentric) will be included in addition to the solid ones considered so far; due to the orthotropic properties, significant changes in load transfer and damage mechanisms are expected compared to solid brick masonry. In addition, different wall thicknesses and brick arrangements are to be considered in order to be able to evaluate influences from theses parameters in the unit-cell tests more precisely for the first time. Finally, an attempt will be made to realistically represent the load-bearing behaviour of strengthened walls with the small-scale test setup. The numerical model will be further developed for the additional questions addressed and validated on the basis of the new experimental findings obtained. The planned additional fibre-optic sensors (e.g. in the mortar joints) will provide valuable additional information on the complex load-bearing mechanisms and enrich and further improve the simulation model. After successful completion of the project, a scientifically validated methodology and a simulation model will be available which, on the basis of the unit-cell approach, allow realistic predictions to be made of the load-bearing and damage behaviour of a wide variety of small-format masonry in existing buildings (made of solid or perforated bricks, various types of brick arrangement) under monotonic/cyclical, centric or eccentric shear-compression loading. Hereby, a much more flexible and powerful tool is available compared to large-scale tests (storey-high shear walls) to realistically assess existing buildings in terms of their behaviour under a wide range of loading scenarios. In addition, configurations that have not been dealt with so far can be added to the overall methodology comparatively easily.