Masonry bridges diagnosis

Despite the common belief is that the language used by engineers exclusively consists of cold technical expressions; in masonry bridges the opposite occurs. Thus, engineers assign human qualities along the restoration and conservation phases of masonry bridges, playing the role of a doctor according to the illness of the structure. The metaphor between building techniques and medicine becomes evident in the terminological correspondences.

About one year ago, I have had the opportunity to design a solution to extend the use of a couple of stone bridges (in the pics you can see one of them) by performing a structural damage analysis. This is not an unfrequent situation: engineers can find many of these old contructions in the roads of Galicia and the North of Portugal and, believe me, it is a challenging issue.

Central arch of the bridge, close to Ourense (left). Analysis with RING (right).

FE Analysis with Cosmos/m

Unfortunately, masonry is quite difficult to analyse without proper tests that cost a lot of money and I realised that finite element models of stone arch bridges give good
estimations of deformations but inaccurate ultimate failure loads. The best software tool I found was the RING program developed at the University of Sheffield that is based on the theory of Jacques Heyman. This software is freeware, easy and rapid to run and provides better results than common finite element packages.