Diagnosis and repair of a historic stone masonry arch bridge

The D. Zameiro Bridge is a multi-span stone masonry arch bridge built between the 12th and 13th centuries that crosses the Ave River in a rural area 40 km North of Porto, Portugal. The bridge is composed of eight arches of different span, with a total length of 130 m. The bridge has been subject to several conservation and repair works along its existence. In 2001, a flood caused the partial collapse of a pier and of the adjacent arches close to left bank. The bridge was repaired in 2003, but a new accident in 2004 caused the collapse of two piers and adjacent arches near the right bank. This paper presents a brief historical note, discusses the inspection works carried out after the collapses and provides the possible reasons for such extreme events. Afterwards, the paper reports the repair works carried out, taking into account the architectural significance of the construction.