Research Output

Risk sensitivity applied to arch bridge assessments: an introduction.

  There are approximately 75,000 masonry arch bridges in the UK, most of which were built between 1700 and 1900 and are now carrying traffic loads far beyond those envisaged by the original designers and builders. A question has to be asked as to whether nominally identical arches will yield identical collapse loads. Large scale tests have been carried out by various researchers, but repeatability tests at this scale have not been carried out because of cost. It was therefore deemed necessary to conduct a series of repeatability tests on large scale arches to give engineers an idea of the reliability of assessed capacities. 3 nominally identical laboratory brickwork arch bridges were built and tested to collapse. The arches collapsed at 21kNm(super-1), 16kNm(super-1) and 25kNm(super-1). 6 arch bridge assessment methods, including 2 novel risk assessment programs coded by the authors, were used to analyse the arches. It was concluded that nominally identical arches may show significantly different behaviour. Statistical analyses should be performed so that the risk involved in assessing an arch, either due to imperfect modelling or variability of the input parameters, can be quantified, thereby making the assessment more reliable.

  • Type:


  • Date:

    18 September 2001

  • Publication Status:


  • Publisher

    Institution of Structural Engineers

  • ISSN:



Ng, K., Fairfield, C. A. & Sibbald, A. (2001). Risk sensitivity applied to arch bridge assessments: an introduction. The structural engineer : journal of the Institution of Structural Engineers. 79, 31-37. ISSN 1466-5123


Arch bridges; Compression testing; Structural loads; Traffic flow; Statistical analysis; Construction costs; Sensitivity; Reliability; Masonry; Mathematical models; Risk assessment

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