Evaluation of Diagnostics and Recalculations of Several Czech Masonry Arch Railway Bridges

Abstract Masonry arch bridges on the railway in the Czech Republic are connected with the construction and development of the railway network in the second half of the 19th century. Many of them have been in service for about 150 years, some of them even for over 180 years. Nowadays, these historical types of bridge structures are not newly designed. Their durability is extraordinary compared to current structures. It can be assumed, that in case of proper maintenance, most of them can serve well for another tens or hundreds of years. Diagnostic surveys and structural recalculations of several masonry arch bridges were carried out between 2022 and 2024 as part of the project “Diagnostics and Recalculations of Strategic Bridges” organized by Czech Railway administration. In this paper, the investigated structures (generally monumental multi-span viaducts) are introduced, their typical failures and problems are presented, and their static reliability is evaluated. The specific approach to performing diagnostic surveys and recalculations of these historical structures is also discussed in detail. In the case of arched masonry structures, the structural analysis and determination of load-bearing capacity is complicated by the complex static behaviour of masonry arched structures combined with typical masonry properties characterised by non-linear behaviour.