Abstract

Masonry arch bridges, despite their age, are still fundamental structures in transport networks throughout Europe, especially for railways. Furthermore, these bridges are often found in seismic-prone areas, such as Italy. Developing of specific fragility models is of fundamental importance for large-scale seismic risk assessments of these structures and related transport networks. Unlike other types of bridges, for which significant progress has been made in assessing their seismic vulnerability and fragility, comparable results for masonry arch bridges are not fully available. Moreover, a realistic risk assessment of masonry bridges should account for deterioration and damage, which most of these bridges have developed being more than 100 years old and often in a poor state of maintenance. Therefore, this work intends to provide seismic fragility models for two generalised classes of single-span masonry arch bridges, i.e. segmental and semi-circular, taking into account their potential degradation through 2 D finite-element modelling and parametric nonlinear static analyses. Material loss from the intrados of the arch, material degradation, and longitudinal cracks on the arch barrel vault are investigated as typical defects. Overall, the seismic fragility of masonry bridges increases appreciably when the effects of degradation are considered, the loss of material being the most influential defect.

摘要

砖石拱桥尽管年代久远，但仍然是整个欧洲交通网络的基本结构，尤其是铁路。此外，这些桥梁经常出现在地震多发地区，例如意大利。开发特定的脆弱性模型对于这些结构和相关交通网络的大规模地震风险评估至关重要。与其他类型的桥梁不同，在评估其地震脆弱性和易碎性方面取得了重大进展，砖石拱桥的可比较结果并不完全可用。此外，对砖石桥梁进行现实的风险评估应该考虑到劣化和损坏，这些桥梁中的大多数已经有 100 多年的历史，而且往往处于维护不善的状态。所以，这项工作旨在为两类广义的单跨砌体拱桥（即节段和半圆形）提供地震易损性模型，通过二维有限元建模和参数非线性静态分析考虑到它们的潜在退化。拱内拱的材料损失、材料退化和拱筒拱顶上的纵向裂缝作为典型缺陷进行了调查。总的来说，考虑到退化的影响，砌体桥梁的地震脆性明显增加，材料损失是影响最大的缺陷。拱内拱的材料损失、材料退化和拱筒拱顶上的纵向裂缝作为典型缺陷进行了调查。总的来说，考虑到退化的影响，砌体桥梁的地震脆性明显增加，材料损失是影响最大的缺陷。拱内拱的材料损失、材料退化和拱筒拱顶上的纵向裂缝作为典型缺陷进行了调查。总的来说，考虑到退化的影响，砌体桥梁的地震脆性明显增加，材料损失是影响最大的缺陷。