Masonry structures constitute the great majority of buildings in historical centers where construction activities were carried out by adding structural portions to pre-existing ones: as a result, masonry aggregates are currently the most common structural typology in such contexts. The structural behavior of masonry aggregates, which are complex systems of different buildings interacting with each other, is generally affected by several factors, such as the different steps of construction, uncertainties about interlocking between walls, presence of different and irregular masonry textures and multi-leaf walls, which make such a structural typology very difficult to study. During recent seismic events in Italy, a wide number of local collapses has been observed in masonry aggregates of historical centers, highlighting the important role of local mechanisms in the seismic assessment of such structures. In this paper, an efficient software called ANUB-Aggregates (Adaptive Nurbs Upper Bound limit analysis for masonry Aggregates) is proposed for the seismic assessment of partial failure mechanisms in historical masonry aggregates. The theoretical core of this program is a kinematic NURBS-based limit analysis with meta-heuristic mesh adaptation. The use of NURBS allows studying aggregates containing vaulted structures, or any other typology of curved elements, without additional computational effort. Moreover, the mesh adaptation scheme assures the representation of the correct collapse mechanism by finding the real position of fracture lines. Starting from the three-dimensional model of the whole aggregate, the code ANUB-Aggregates provides the analysis of more macro-elements interacting with each other with different interlocking hypotheses, evaluating both simple and complex failure mechanisms. As proof of the effectiveness of this applicative, the analysis of two historical masonry aggregates is presented.

中文翻译：

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ANUB-Aggregates：基于NURBS的全自动软件，用于对历史砌体骨料进行​​高级局部破坏分析

砖石结构构成了历史中心建筑物中的绝大部分建筑物，在这些历史中心中，通过向先前存在的结构部分中添加结构部分来进行建筑活动：因此，在这种情况下，砖石集料目前是最常见的结构类型。砌体集料的结构行为是不同建筑物之间相互作用的复杂系统，通常受几个因素影响，例如不同的施工步骤，墙体之间互锁的不确定性，不同和不规则的砌体纹理的存在以及多种结构。叶壁，这使得这种结构类型学很难研究。在意大利最近发生的地震事件中，在历史中心的砌体中发现了许多局部倒塌，强调了局部机制在此类结构的地震评估中的重要作用。本文提出了一种称为ANUB-Aggregates（砌体骨料的自适应Nurbs上限分析）的有效软件，用于对历史砌体骨料的部分破坏机理进行地震评估。该程序的理论核心是基于运动的基于NURBS的极限分析和元启发式网格自适应。使用NURBS可以研究包含拱形结构或任何其他弯曲元素类型的骨料，而无需进行额外的计算。此外，网格自适应方案通过找到断裂线的实际位置来确保表示正确的塌陷机制。从整体的三维模型开始 代码ANUB-Aggregates可以分析更多具有互锁假设的相互影响的宏元素，从而评估简单和复杂的故障机制。为了证明此应用程序的有效性，提出了两种历史砌体集合体的分析。