Abstract

A probabilistic analysis approach for reliability-based assessment of masonry arch bridges is presented in this work. The methodology is tested on a medieval in-service construction located in Galicia, northwest of Spain. To estimate its ultimate load-carrying capacity, two different numerical approaches are employed; a three-dimensional non-linear finite element model and a two-dimensional rigid blocks limit analysis model. Aiming to alleviate the computational burden associated with the probabilistic analysis procedure, a surrogate modelling strategy is adopted. A complete understanding of the influence of model input parameters on the limit load of the structure is attained through the employment of global variance-based sensitivity analysis. The reliability assessment procedure is subsequently carried out, allowing to estimate the bridge failure probability. A difference of approximately 33% is obtained between the reliability index values drawn from both structural modelling strategies, so revealing the key role played by transversal effects on the strength capacity of masonry arch bridges. The proposed probabilistic assessment framework might be deemed as a useful tool, from which more reliable and objective information about the actual safety condition of existing masonry arch bridges can be derived, taking advantage of readily available numerical tools, but still demanding an affordable computational effort.

摘要

这项工作提出了一种基于概率分析的砌体拱桥可靠性评估方法。该方法在位于西班牙西北部加利西亚的中世纪在役建筑中进行了测试。为了估算其最终承载能力，采用了两种不同的数值方法。一个三维非线性有限元模型和一个二维刚性块极限分析模型。为了减轻与概率分析程序相关的计算负担，采用了替代建模策略。通过基于全局方差的敏感性分析，可以完全理解模型输入参数对结构极限载荷的影响。随后执行可靠性评估程序，可以估计桥梁失效的可能性。从这两种结构建模策略得出的可靠性指标值之间大约有33％的差异，因此揭示了横向作用对砌体拱桥强度能力的关键作用。提议的概率评估框架可能被认为是有用的工具，利用现有的数值工具，可以从中得出有关现有砌体拱桥实际安全状况的更可靠和客观的信息，但仍需要可负担的计算工作。因此揭示了横向作用对砌体拱桥强度的关键作用。提议的概率评估框架可能被认为是有用的工具，利用现有的数值工具，可以从中得出有关现有砌体拱桥实际安全状况的更可靠和客观的信息，但仍需要可负担的计算工作。因此揭示了横向作用对砌体拱桥强度的关键作用。提议的概率评估框架可能被认为是有用的工具，利用现有的数值工具，可以从中得出有关现有砌体拱桥实际安全状况的更可靠和客观的信息，但仍需要可负担的计算工作。