Application of the finite/discrete element method to arches

During the last 10 years UK engineering consultancy Gifford has been assessing masonry arch bridges and using the finite/discrete-element method to predict their structural behaviour. In the majority of cases this work has followed bridge strength assessments based on traditional techniques where under-strength bridges are first identified. Over 200 bridges have now been investigated ranging from small rural bridges in the UK to massive structures used by Indian Railways, and a significant economic and environmental benefit gained through their continued use. This paper describes how the finite/discrete-element method has been applied and verified and covers the description of a development programme including full-scale laboratory tests, supplementary load tests on bridges in the field, and several monitoring programmes. The advantages this technique can provide over conventional arch bridge analyses, both limit analysis (mechanism) and traditional finite-element modelling, are described and how through partnering an innovative assessment and strengthening service is being delivered. The relevance of this approach to emerging serviceability limit state arch bridge assessment, which is seen as being particularly important for railways, is also discussed.