ABSTRACT

Conservation of the European-built heritage is nowadays closely related to interventions in masonry construction. Since a significant part of these structures are located in earthquake prone zones, designing protective measures that ensure their preservation requires the assessment of the associated seismic vulnerability and the understanding of their degradation mechanisms. However, due to the presence of discontinuities between its constituent elements, the numerical simulation of the non-linear response of masonry structures subjected to strong earthquakes is a cumbersome task, especially when performed using the traditional finite element method. As an alternative, the discrete element method is particularly suitable for the numerical analysis of such structures under large, damaging loads. By allowing discrete displacements/rotations of individual bodies, and by automatically recognising new contacts between bodies, while eliminating obsolete ones, this numerical approach can simulate the complete detachment of discrete bodies initially in contact. The present paper illustrates the use of the discrete element method to assess the seismic vulnerability of stone arches. A probabilistic approach allows to consider the variability of the seismic action and the uncertainties in the definition of the material properties. First, an un-reinforced masonry arch is considered. Based on non-linear multi-directional incremental dynamic analyses, five damage states are proposed and the respective fragility curves are elaborated. To improve the arch’s seismic performance, two reinforcing solutions using steel elements are considered and analysed comparatively.

摘要

如今，保护欧洲建造的遗产与砖石建筑的干预密切相关。由于这些结构中的很大一部分位于地震多发区，因此设计保护措施以确保它们的保存需要评估相关的地震脆弱性并了解它们的退化机制。然而，由于其组成元素之间存在不连续性，强震作用下砌体结构非线性响应的数值模拟是一项繁琐的任务，尤其是在使用传统的有限元方法进行时。作为替代方案，离散元方法特别适用于在大的破坏性载荷下对此类结构进行数值分析。通过允许单个物体的离散位移/旋转，并通过自动识别物体之间的新接触，同时消除过时的接触，这种数值方法可以模拟最初接触的离散物体的完全分离。本文阐述了使用离散元法评估石拱的地震易损性。概率方法允许考虑地震作用的可变性和材料特性定义中的不确定性。首先，考虑一个未加固的砖石拱。基于非线性多向增量动力学分析，提出了五种损伤状态，并详细阐述了各自的脆性曲线。为提高拱的抗震性能，