Discussion: Rationalising assessment approaches for masonry arch bridges Available to Purchase

Papers of this type take a deal of work and considerable thought (Gibbons and Fanning, 2012). The authors are to be thanked for their efforts.

The contributor wishes to take issue with two statements they make before raising his main point. In Section 2.2.2 the authors state that the Ring program (which is not the contributor's), being based on the formation of four plastic hinges, can be considered as an upper bound solution. This is a misreading of the plastic theorems. Ring satisfies both the mechanism and the equilibrium conditions, and indeed as it considers material strength, the...