This paper presents an integrated approach that combines advanced survey procedures, such as close range photogrammetry based on high resolution images provided by Unmanned Aerial Vehicles, and Ambient Vibration Tests to develop accurate Finite Element models of severely damaged historic masonry structures. The proposed methodology is applied to a masonry arch bridge located in Todi, Central Italy, characterized by severe damage conditions involving diffuse material degradation and structural damages. Two numerical models are developed starting from the digital geometric survey: the first accurately describes the irregular actual geometry due to damage; the second regularizes the boundary surfaces as standard procedure in common practice when detailed survey is not available. The crucial role of the geometric irregularities given by the severe damage state on the dynamic properties of the masonry bridge is demonstrated by comparing the modal parameters of the two models. Furthermore, sensitivity analysis is carried out in order to assess the combined effect of different mechanical characteristics and geometric configurations on the modal properties and to select suitable updating parameters. The overall methodology is completed by a final model updating procedure targeting the experimental modal parameters estimated from Ambient Vibration Tests.

本文提出了一种综合方法，该方法结合了先进的测量程序，例如基于无人飞行器提供的高分辨率图像的近距离摄影测量法和环境振动测试，以开发严重受损的历史性砖石结构的精确有限元模型。所提出的方法应用于位于意大利中部托迪的砌体拱桥，其特征是严重的破坏条件，包括扩散的材料降解和结构破坏。从数字几何调查开始，开发了两个数值模型：第一个精确描述由于损坏而引起的不规则实际几何形状；当无法进行详细测量时，第二种方法将边界表面规范化为通常做法中的标准程序。通过比较两个模型的模态参数，可以证明严重损坏状态给定的几何不规则性对砌体桥动力特性的关键作用。此外，进行灵敏度分析以评估不同机械特性和几何构型对模态特性的综合影响，并选择合适的更新参数。通过针对环境振动测试估算的实验模态参数的最终模型更新程序，可以完成整体方法。进行灵敏度分析是为了评估不同机械特性和几何构型对模态特性的综合影响，并选择合适的更新参数。通过针对环境振动测试估算的实验模态参数的最终模型更新程序，可以完成整体方法。进行灵敏度分析是为了评估不同机械特性和几何构型对模态特性的综合影响，并选择合适的更新参数。通过针对环境振动测试估算的实验模态参数的最终模型更新程序，可以完成整体方法。