Structural analysis and maintenance policy for historical bridges

In the paper a concise description of historical masonry bridges is presented, focusing attention on the technological point of view. A summary review of the development of basic concepts in the statics of masonry arcades is attempted, and a possible theoretical approach, based on the assumption that the masonry cannot resist tension, is briefly explained. The theory is illustrated by examples, that demonstrate that practical results are in perfect agreement with engineering insight, adding, of course, a quantitative measure of phenomena (fractures, stresses, displacements and so on).

As a second step, an analysis of the maintenance strategy for historical bridges is attempted, based upon the ascertainment that it has survived, practically without maintenance, up to day. To this end a basic rationale developped by the writer, is applied, based on reliability concepts and a probabilistic approach to comparative evaluation of different policies is applied. On the basis of these results, one can conclude that simple maintenance works might significantly improve the statics of the bridge and its duration.