A spatial view of the flow of force in masonry bridges

Abstract

Owners need to be able to determine, with some certainty, which of their bridges are at risk of damage by loading and which are not. The underlying rules of distribution encapsulated in current assessment codes for arch bridges are not capable of yielding useful results. It is not, therefore, possible to distinguish effectively between those bridges which have an indefinite life and those which will fail in the near future if loads are increased. Experience suggests that short-span bridges with shallow fill are most at risk and increasing either span or fill depth reduces the risk dramatically. A useful model must be capable of following this trend. The paper presents evidence of failure under live load, a proposal for a new (still relatively simple) model for distribution and a link between that simple model and results from tests and analysis.