Stone arch bridges built before 1550

Although the complexity and importance of bridge projects was comparable to cathedral building, this important corpus of medieval constructions has received very little attention by building archeology so far. A nw research project at the Chair of Building Archaeology and Construction History (Prof. Dr.-Ing. Stefan M. Holzer) at the Institute for Conservation and Building Research (IDB) aims at understanding better the bridges’ building and repair history.

Establishing a permanent stone arch bridge posed a serious financial and technical challenge to medieval communities, tasks ranging from stone quarrying and stoneworking, laying the foundations in the riverbed, to the final easing of the centring under the completed arches. On-site building archeology is the most promising approach to untangle the bridges’ building and repair history, since archival sources (although abundant) typically provide very little technical detail. In the project, detailed geometrical surveys of the bridges will be created by means of advanced technologies like laser scanning, structure-from-motion photogrammetry employing drone-mounted or cable-car-suspended cameras, as well as automated feature extraction. Precise surveys permit to correlate findings and traces and to reconstruct details of the design and construction procedures. Contextualization of the individual monuments will be achieved by focusing on some particularly dense clusters of preserved bridges, notably, in Southwestern France and Central Italy.