Stress-Life Curves Method for Fatigue Assessment of Ancient Brick Arch Bridges

Estimating the saftey of an ancient masonry arch bridge is a legitimate, but very interesting, structural engineering challenge. This is due to the fact that most of these bridges are still in service and suffer from higher and more frequent cyclic loads, a problem not encountered in the past. Therefore, for these structures it is important to know the actual fatigue strength rather than the ultimate carrying capacity in order to provide useful indications on the remaining service life with also possible traffic load limitations. In this article, different models are applied according to the stress-life curve method for estimating the fatigue strength of a case study: an ancient multi-span masonry arch bridge still in service. The obtained results highlight that, unlike steel elements, current design codes do not provide any relevant indication as to the fatigue strength assessment of existing masonry membratures. Moreover, appropriate stress-life curves are needed for evaluating the actual capacity and residual service life of low-strength masonry elements under cycling loads.