Enrico Tubaldi^1,2, Lorenzo Macorini¹, and Bassam A. Izzuddin¹
1)  Department of Civil & Environmental Engineering, Imperial College London
London
{e.tubaldi,l.macorini,b.izzuddin}@imperial.ac.uk
2)  Department of Civil & Environmental Engineering, Strathclyde University
Glasgow
e-mail: enrico.tubaldi@strath.ac.uk

Keywords: Masonry arch bridges, Multiple spans, Mesoscale model, Backfill, Load capacity.

Abstract. Many masonry arch bridges in Europe cross waterways and are exposed to the flood hazard. Despite flood-induced actions are responsible for the failure of many of these bridges, accurate procedures to systematically assess their effects have yet to be proposed. This paper describes an advanced three-dimensional modelling strategy for describing the behaviour of multi-span masonry arch bridges subjected to pier scour, which is one of the most critical flood induced action. A mesoscale description is employed for representing the heterogeneous behaviour of masonry units, mortar joints and brick-mortar interfaces, whereas a domain partitioning approach allowing for parallel computation is used to achieve computational efficiency. The proposed modelling approach, realised using ADAPTIC, is first validated by comparison with available experimental tests on masonry arch bridge models subjected to scour-induced settlements. Then, a numerical example consisting of a multi-span arch bridge subjected to pier scour is presented to illustrate the potential of the proposed modelling approach, and its unique capabilities for evaluating the vulnerability and risk of masonry arch bridges under flood scenarios.