“Ponte delle Cianche” at Buonalbergo, Italy: a Trajan's era bridge in an earthquake prone region

Ancient Romans built more than one thousand arch bridges throughout their empire. Among them is the “Ponte delle Chianche” located close to Buonalbergo, Italy, along the “Via Traiana”, the alternative path to the “Via Appia” between Benevento and Brindisi built around AD 110. This bridge is a very interesting example of the so-called Trajan’s type, presenting arches of variable span and springing height (to deliver the desired profile on an uneven valley) as well as fired clay brickwork veneers and vaults. The internal structure of the piles and of the backfill is a Roman concrete. The construction is about 7 m wide, 120 m long and had six spans at least until the beginning of the 20th century, while the fifth is not standing anymore. During its history the bridge has survived several earthquakes, of which a list is derived by applying an attenuation law to the Italian database of macroseismic events. It is noteworthy to observe that Pliny the Elder (1st century) suggested the use of brickwork, instead of stonework, as more earthquake resistant. The paper documents planned investigations for future vulnerability assessment on this remarkable arch bridge.