Unreinforced masonry buildings undergoing seismic actions often exhibit local failure mechanisms which represent a serious life-safety hazard, as recent strong earthquakes have shown. Compared to new buildings, older unreinforced masonry buildings are more vulnerable, not only because they have been designed without or with limited seismic loading requirements, but also because horizontal structures and connections amid the walls are not always effective. Also, Out-Of-Plane (OOP) mechanisms can be caused by significant slenderness of the walls even if connections are effective. The purpose of this paper is to derive typological fragility functions for unreinforced masonry walls considering OOP local failure mechanisms. In the case of slender walls with good material properties, the OOP response can be modeled with reference to an assembly of rigid bodies undergoing rocking motion. In particular, depending on its configuration, a wall is assumed either as a single rigid body undergoing simple one-sided rocking or a system of two coupled rigid bodies rocking along their common edge. A set of 44 ground motions from earthquake events occurred from 1972 to 2017 in Italy is used in this study. The likelihood of collapse is calculated via Multiple Stripe Analysis (MSA) from a given wall undergoing a specific ground motion. Then, the single fragility functions are suitably combined to define a typological fragility function for a class of buildings. The procedure is applied to a historical aggregate in the city center of Ferrara (Italy) as a case study. The fragility functions developed in this research can be a helpful tool for assessing seismic damage and economic losses in unreinforced masonry buildings on a regional scale.

经历地震作用的未加固砖石建筑经常表现出局部破坏机制，这代表了严重的生命安全危害，正如最近的强地震所表明的那样。与新建筑相比，旧的未加固砖石建筑更容易受到破坏，这不仅是因为它们的设计没有或只有有限的地震荷载要求，而且还因为墙体之间的水平结构和连接并不总是有效。此外，即使连接有效，面外 (OOP) 机制也可能由墙壁的显着细长引起。本文的目的是推导出考虑 OOP 局部破坏机制的无钢筋砌体墙的类型脆弱性函数。在具有良好材料特性的细长墙壁的情况下，OOP 响应可以参考经历摇摆运动的刚体组件进行建模。特别是，根据其配置，墙被假定为经历简单单侧摇摆的单个刚体或沿其公共边缘摇摆的两个耦合刚体的系统。本研究使用了 1972 年至 2017 年发生在意大利的地震事件的 44 次地面运动。倒塌的可能性是通过多条带分析 (MSA) 从给定的墙体经历特定的地面运动来计算的。然后，将单个脆弱性函数适当地组合起来，为一类建筑物定义类型学脆弱性函数。作为案例研究，该程序被应用于费拉拉（意大利）市中心的一个历史总量。