C. MELBOURNE and M. GILBERT Bolton Institute of Higher Education

A series of tests on large scale model multi-ring brickwork arch bridges has been undertaken in order to determine the significance of ring separation on their behaviour. Ring separation occurs when there is a loss of structural adhesion between adjacent rings of brickwork in the arch barret. It was found that the bridges with the defect suffered a substantial loss of strength relative to comparable bridges without the defect. Where partial ring separation occurred during, and therefore as a result of, the loading, significant strength losses were recorded. An analysis method using discrete rigid elements has been developed which can be used to analyse bridges with full or partial ring separation.