Probabilistic-based assessment of a masonry arch bridge considering inferential procedures


Moreira, Vicente Novo; Matos, José C.; Oliveira, Daniel V.

Safety assessment; Bayesian inference; Masonry arch bridges; Limit analysis; Uncertainty source; Non-destructive tests; Railway bridges; Uncertainty sources

Considering the safety assessment requirements of masonry arch bridges, different levels of reliability,based on uncertainty, may be distinguished, whose core objectives are to accurately analyse the ultimateload-carrying capacity and the serviceability structural response. Within this framework, a simplifiedfull-probabilistic methodology for the safety assessment of existing masonry arch bridges is proposed,which combines both structural analysis and Bayesian inference procedures. The proposed frameworkaims to determine the ultimate load-carrying capacity (Ultimate Limit State) of masonry arch bridges,by using probabilistic procedures and Limit States principles. Geometric, material and load characterization,as well as inherent uncertainties will be also considered. In order to determine the ultimate loadcarryingcapacity, a limit analysis approach, based on the mechanism method, will be employed. Dueto the high computational costs required by a probabilistic safety assessment framework, a sensitivityanalysis will then be introduced. The incorporation of new information from monitoring and/or testingwill be performed by the application of Bayesian inference methodologies. Based on the information collected,two reliability indexes will be computed and compared, one with data collected from design documentationand literature and the other with data collected from testing, emphasizing the importance oftesting and the advantages of Bayesian inference procedures. The probabilistic framework developed istested and validated in a Portuguese railway masonry arch bridge from the 19th century.