C Melbourne and J Wang
School of Computing, Science and Engineering, University of Salford

In the United Kingdom many existing masonry arch bridges have been subject to alteration and extension in order to continue to contribute to the transportation network. One type of alteration is the introduction of full-height longitudinal brickwork diaphragm walls under the arch barrel. These are confined to side spans under which a clear span is not required. At present there is no guidance to the assessing engineer as to how the arch barrel is to be idealised for analysis.
The principal aim of this research programme was to determine the effect that diaphragm supports have on the load carrying capacity of single span brickwork arches and make recommendations regarding the assessment method for this type of structure. At the same time the research will provide robust experimental data which can be used to validate FE models.
The paper will present the results from two laboratory tests on multi-ring brickwork square span arches. One arch comprised “strong” brickwork (24.5N/mm2) whilst the other was constructed using “weak brickwork” (9.1N/mm2). Each arch was tested with two different support conditions in the elastic range. The first with the arch supported only at its springings; the second with the addition of point supports to replicate longitudinal diaphragms. Both arches were loaded to failure with intrados supports. Three-dimensional FE macro-model is used to simulate the tests. The significance of the diaphragm supports on the 3-dimensional behaviour of the arch barrels is discussed and general conclusions and recommendations are presented.