The shallow arch: A step towards bridges styling in the early 19th century

Several formulations for masonry arches were appearing since 18th century, mostly based on the acquired experience in bridge construction. That led to a generalized use of shallow arch. The innovations supposed an evolution in the shape of masonry arch bridges, at the expense of increasing the thickness of voussoirs and vault. The question is: were the mentioned changes related with a clear structural improvement? Or were they mainly aesthetic or fashion-driven changes? This paper tries to give deeper insight and response this query by making a comparison among different formulations, and analyzing the rise to span ratio and backfill influences in both ultimate load capacity and maximum stress. Moreover, a multi-span arch bridge is analyzed, performing a comparison among different typological possibilities, and using examples of real structures in the Carrión river basin (Spain).