Ponte San Lorenzo
Encyclopedia
The Ponte San Lorenzo is a Roman segmental arch bridge over the river Bacchiglione
in Padua
, Italy
. Constructed between 47 and 30 BC, it is one of the very earliest segmental arched bridges in the world. It is also notable for the slenderness of its pier
s, unsurpassed in antiquity
.
s in ancient Padua crossing the Medoacus (modern Bacchiglione). Located in the Via San Francesco, the three-arched bridge is today for the most part framed by surrounding buildings, which have moved closer to the river over the centuries. Only its eastern arch
spanning the restricted waterway was largely visible until the middle of the 20th century, when it too disappeared from view as the remaining canal was filled up to the Riviera del Ponti Romani street. The intact arches of the bridge still exist below street level and can be visited at fixed times by the public. Earthworks in 1773 and 1938, during which parts of the bridge were temporarily excavated, were used for archaeological investigations.
Two further Roman bridges in Padua are obstructed from sight, the Ponte Corbo, also located in the Via San Francesco, and the completely inaccessible Ponte Altinate
in the Via Altinate. Both bridges also rest on segmented arches, as does the above-ground Ponte Molino
. The fifth Roman bridge in town is the Ponte S. Matteo close to the church of the same name.
The pier thickness of Roman bridges varies - as far as determined - between one half and one fifth of the span. Small piers offer less resistance to the water flow, thus reducing the risk of undermined foundations. On the other hand, all piers have to be strong enough to accommodate two arch ribs. The pier thickness of the Ponte San Lorenzo measures only 1.72 m, which corresponds to no more than one eighth of the span of the central opening, a value not to be achieved again until the High Middle Ages
.
Bacchiglione
The Bacchiglione is a river that flows through northern Italy. It rises in the Alps and empties into the Gulf of Venice, on the Adriatic Sea, near Chioggia...
in Padua
Padua
Padua is a city and comune in the Veneto, northern Italy. It is the capital of the province of Padua and the economic and communications hub of the area. Padua's population is 212,500 . The city is sometimes included, with Venice and Treviso, in the Padua-Treviso-Venice Metropolitan Area, having...
, Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
. Constructed between 47 and 30 BC, it is one of the very earliest segmental arched bridges in the world. It is also notable for the slenderness of its pier
Pier
A pier is a raised structure, including bridge and building supports and walkways, over water, typically supported by widely spread piles or pillars...
s, unsurpassed in antiquity
Classical antiquity
Classical antiquity is a broad term for a long period of cultural history centered on the Mediterranean Sea, comprising the interlocking civilizations of ancient Greece and ancient Rome, collectively known as the Greco-Roman world...
.
Location
The Ponte San Lorenzo was one of four Roman bridgeRoman bridge
Roman bridges, built by ancient Romans, were the first large and lasting bridges built. Roman bridges were built with stone and had the arch as its basic structure....
s in ancient Padua crossing the Medoacus (modern Bacchiglione). Located in the Via San Francesco, the three-arched bridge is today for the most part framed by surrounding buildings, which have moved closer to the river over the centuries. Only its eastern arch
Arch
An arch is a structure that spans a space and supports a load. Arches appeared as early as the 2nd millennium BC in Mesopotamian brick architecture and their systematic use started with the Ancient Romans who were the first to apply the technique to a wide range of structures.-Technical aspects:The...
spanning the restricted waterway was largely visible until the middle of the 20th century, when it too disappeared from view as the remaining canal was filled up to the Riviera del Ponti Romani street. The intact arches of the bridge still exist below street level and can be visited at fixed times by the public. Earthworks in 1773 and 1938, during which parts of the bridge were temporarily excavated, were used for archaeological investigations.
Two further Roman bridges in Padua are obstructed from sight, the Ponte Corbo, also located in the Via San Francesco, and the completely inaccessible Ponte Altinate
Ponte Altinate
The Ponte Altinate is a Roman segmented arch bridge in Padua, Italy. The late Republican bridge once spanned a branch of the Brenta river whose course is today followed by the street Riviera del Ponti Romani...
in the Via Altinate. Both bridges also rest on segmented arches, as does the above-ground Ponte Molino
Ponte Molino (Padua)
The Ponte Molino is a Roman segmental arch bridge across the Bacchiglione in Padua, Italy. The span-to-rise ratio of the Late Republic bridge varies between 3.5–4.5 and 1, the ratio of clear span and pier thickness between 4–6.5 and 1....
. The fifth Roman bridge in town is the Ponte S. Matteo close to the church of the same name.
Construction
The Ponte San Lorenzo is 53.30 m long and 8.35 m wide. The date of its construction is fixed by a bridge inscription to between 47 and 30 BC. The bridge is of particular importance in the history of ancient technology for its flattened arches and slender piers. Its three arches span 12.8 m, 14.4 m and 12.5 m, with the span 3.7 times the rise, or, differently put, describing a segment of a circle of 113°. The profile of the structure thus considerably differs from the typical Roman semi-circular bridge arch with its value of 180°.The pier thickness of Roman bridges varies - as far as determined - between one half and one fifth of the span. Small piers offer less resistance to the water flow, thus reducing the risk of undermined foundations. On the other hand, all piers have to be strong enough to accommodate two arch ribs. The pier thickness of the Ponte San Lorenzo measures only 1.72 m, which corresponds to no more than one eighth of the span of the central opening, a value not to be achieved again until the High Middle Ages
High Middle Ages
The High Middle Ages was the period of European history around the 11th, 12th, and 13th centuries . The High Middle Ages were preceded by the Early Middle Ages and followed by the Late Middle Ages, which by convention end around 1500....
.