First application of reinforced concrete in Spain and first European application in bridges: The rehabilitation of the Roman bridge of Alcántara

Abstract

The Alcántara Bridge is one of the most important Roman bridges in the world and has been a Spanish National Monument since 1924. Since its construction, almost two thousand years ago, it has suffered numerous damages due to the passage of time and human action, which has led to different interventions. The most important was that carried out by Millán (1856–1860), for the reconstruction of the arch demolished in 1810. During a visit to the bridge, areas with reinforced concrete were observed. Given the areas where it appears, the geometry of the reinforcement and its configuration, is possible to think that it is a very old intervention, which could date from the same period as that carried out by Millán. If so, it would be the first application of reinforced concrete in Spain and one of the first in the world. The aim of this study is to date the intervention and validate the initial hypothesis. To this end, based on a 3D survey of the rehabilitated areas using a drone, a comparative analysis has been carried out with the plans of Millán's project, as well as sheets and photographs from different periods to establish the date of the interventions. Research was also carried out in the archives of the Real Academia de Bellas Artes de San Fernando to gather information on the interventions on the bridge throughout the 19th century. Finally, the geometry and layout of the reinforcement is analysed in relation to the knowledge of reinforced concrete from its first patents worldwide to its widespread application in Spain. These analyses allow us to conclude that the date of the reinforced concrete repairs on the bridge is undoubtedly 1857, which would be the first application in Spain and the first in Europe on bridges.