Editing Roman bridge

{{Short description|Bridges built by ancient Romans}}
{{About||a list|List of Roman bridges|the railway station in Wales|Roman Bridge railway station}}
{{Use dmy dates|date=March 2022}}
[[File:Puente Romano y Puente de Lusitania, Mérida.jpg|thumb|300px|[[Puente Romano, Mérida]], the world's longest (still in use) surviving Roman bridge]]
The [[ancient Romans]] were the first civilization to build large, permanent [[bridges]].<ref>{{harvnb|O'Connor|1993|p=1}}</ref> Early Roman bridges used techniques introduced by [[Etruscan civilization|Etruscan]] [[immigrants]], but the Romans improved those skills, developing and enhancing methods such as [[arch]]es and [[keystones]]. There were three major types of '''Roman bridge''': wooden, pontoon, and stone. Early Roman bridges were wooden, but by the 2nd century BC stone was being used. Stone bridges used the arch as their [[Arch bridge|basic structure]], and most used [[Roman concrete|concrete]], the first use of this material in bridge-building.

== History ==

Following the conquests of [[Tarquinius Priscus]], [[Etruscan architecture|Etruscan engineers]] migrated to Rome, bringing with them their knowledge of bridge-building techniques. The oldest bridge in [[ancient Rome]] was the [[Pons Sublicius]].<ref name="aldrete">{{Cite book |last=Aldrete |first=Gregory S. |url=https://books.google.com/books?id=zHE4UJQ0XRIC |title=Floods of the Tiber in Ancient Rome |date=5 March 2007 |publisher=JHU Press |isbn=978-0-8018-9188-5 |language=en}}</ref><ref name="whitney">{{Cite book |last=Whitney |first=Charles S. |url=https://books.google.com/books?id=ryW-Qo3Hr3sC |title=Bridges of the World: Their Design and Construction |date=1 January 2003 |publisher=Courier Corporation |isbn=978-0-486-42995-3 |language=en}}</ref>  It was built in the 6th century BC by [[Ancus Marcius]] over the [[Tiber River]].<ref name="whitney" /><ref name="corbishley">{{Cite book |last=Corbishley |first=Mike |url=https://books.google.com/books?id=uo4JN29FNPEC&dq=Bridges+in+Ancient+Rome&pg=PA24 |title=Illustrated Encyclopedia of Ancient Rome |date=2004 |publisher=Getty Publications |isbn=978-0-89236-705-4 |pages=24 |language=en}}</ref> The Romans improved on [[Etruscan architecture|Etruscan architectural]] techniques. They developed the [[voussoir]], stronger [[keystones]], [[Vault (architecture)|vaults]], and superior arched bridges.<ref name="bunson">{{Cite book |last=Bunson |first=Matthew |url=https://books.google.com/books?id=T5tic2VunRoC&dq=Construction+of+Roman+bridges&pg=PA194 |title=Encyclopedia of the Roman Empire |date=2014-05-14 |publisher=Infobase Publishing |isbn=978-1-4381-1027-1 |pages=194 |language=en}}</ref><ref>{{cite book |last=Robertson |first=D.S. |title=Greek and Roman Architecture |date=1943 |publisher=Cambridge University Press |edition=2nd |page=231 |quote=The Romans were the first builders in Europe, perhaps the first in the world, fully to appreciate the advantages of the arch, the vault and the dome.}}</ref> Roman arched bridges were capable of withstanding more stress by dispersing forces across bridges.<ref name="oleson" /> Many Roman bridges had semicircular arches, but a few were [[Segmental arch|segmental]], i.e. with an arc of less than 180 degrees.<ref name="beall">{{cite web |last=Beall |first=Christine |date=1 September 1988 |title=Designing the segmental arch |url=https://www.concreteconstruction.net/_view-object?id=00000154-2575-db06-a1fe-777dacdc0000 |access-date=21 March 2022 |publisher=The Aberdeen Group |via=Concrete Construction}}</ref> 

[[File:Roma-Ponte rotto02.jpg|thumb|[[Pons Aemilius]], the oldest stone bridge in Rome]]
By the 2nd century BC, the Romans had further refined their bridge-building techniques, using stronger materials such as [[volcanic ash]], [[Limestone|lime]] and [[gypsum]]. Also, they began to use [[Clamp (tool)|iron clamps]] to hold together bridges, constructing midstream arches, and [[pentagon]]al stones to allow for wider [[Vault (architecture)|vaults]].<ref name="dupre">{{Cite book |last=Dupré |first=Judith |url=https://books.google.com/books?id=om5FDgAAQBAJ&q=History+of+Roman+bridges |title=Bridges: A History of the World's Most Spectacular Spans |date=2017-11-07 |publisher=Running Press |isbn=978-0-316-47380-4 |language=en}}</ref> According to Canadian classicist [[John Peter Oleson]], no known stone bridges existed in Italy before the 2nd century BC.<ref name="oleson">{{Cite book |last=Oleson |first=John Peter |url=https://books.google.com/books?id=jrsVDAAAQBAJ&q=Bridges+in+Ancient+Rome |title=The Oxford Handbook of Engineering and Technology in the Classical World |date=2008 |publisher=Oxford University Press |isbn=978-0-19-973485-6 |pages=259, 456, 569–571 |language=en}}</ref><ref>{{Cite web |last=Oleson |first=John Peter |date=June 13, 2018 |title=BRIEF BIOGRAPHY |url=http://web.uvic.ca/~jpoleson/#toc }}</ref> This view is not supported unanimously: Spanish engineer [[:es:Leonardo_Fernández_Troyano|Leonardo Fernández Troyano]] suggested that stone bridges have existed since [[Italic peoples|Pre-Roman Italy]].<ref name="troyano">{{Cite book |last=Troyano |first=Leonardo Fernández |url=https://books.google.com/books?id=0u5G8E3uPUAC |title=Bridge Engineering: A Global Perspective |date=2003 |publisher=Thomas Telford |isbn=978-0-7277-3215-6 |pages=86, 94, 100–107 |language=en}}</ref><ref>{{Cite web |title=main |url=https://www.cfcsl.com/en/ |access-date=2022-03-12 |website=CFCSL |language=en-US}}</ref> 

Between 150 and 50 BC, many stone Roman bridges were built, the [[Pons Aemilius]] being the first.<ref name="aldrete" /><ref>{{Cite book |last1=Proske |first1=Dirk |url=https://books.google.com/books?id=8m1I6ERB0HEC&dq=Construction+of+Roman+bridges&pg=PA37 |title=Safety of historical stone arch bridges |last2=Gelder |first2=Pieter van |date=2009-09-18 |publisher=Springer Science & Business Media |isbn=978-3-540-77618-5 |pages=37–38 |language=en}}</ref> Engineers began to use stone instead of wood to exemplify the ''[[Pax Romana]]'' and to construct longer-lasting bridges.<ref name="bove">{{Cite book |last1=Bove |first1=L. |title=The Stone Bridges in Southern Italy: From the Roman Tradition to the Middle of the 19th Centuries |last2=Bergamasco |first2=I. |last3=Lippiello |first3=M. |publisher=Dipartimento di Costruzioni e Metodi Matematici in Architettura Università degli Studi di Napoli – Facoltà di Architettura |year=2004 |pages=3–4 |language=English}}</ref> These were the first large-scale bridges ever constructed.<ref name="dupre" /> Bridges were constructed by the Roman government to serve the needs of the [[Military of ancient Rome|military]] and the empire's administration. Sometimes roads and bridges were used for commercial purposes, but this was rare as boats better served the needs of the [[Roman economy]].<ref name="ruddock">{{Cite book |last=Ruddock |first=Ted |url=https://books.google.com/books?id=ulsPEAAAQBAJ&dq=History+of+Roman+bridges&pg=PR21 |title=Masonry Bridges, Viaducts and Aqueducts |date=2017-05-15 |publisher=Routledge |isbn=978-1-351-91928-9 |pages=XXI, 15–23 |language=en}}</ref>

By the 2nd century Roman techniques had declined, and they had been mostly lost by the 4th century.<ref name="whitney" /> Some Roman bridges are still used today, such as the [[Pons Fabricius]], and even after the [[Fall of the Western Roman Empire]], engineers copied their bridges.<ref name="maynard" /> Roman bridge-building techniques persisted until the 18th century:<ref name="whitney" /> for example, the prevalence of arches in bridges can be attributed to the Romans.<ref name="ruddock" />

== Construction ==
=== Measurements ===
[[File:Sant Angelo bridge.jpg|thumb|left|[[Ponte Sant'Angelo]]]]
Roman bridges were much larger than the bridges of other civilizations. They could be anywhere from {{convert|4.6|to|18.3|m}} long. By the time of [[Augustus]] around the turn of the 1st millennium the maximum span of Roman bridges increased from around {{convert|24|m}} in 142 BC to {{convert|35|m}}.<ref>{{Cite book |last1=Gagarin |first1=Michael |url=https://books.google.com/books?id=lNV6-HsUppsC&q=Bridges+in+Ancient+Rome |title=The Oxford Encyclopedia of Ancient Greece and Rome |last2=Fantham |first2=Elaine |author2-link=Elaine Fantham |date=2010 |publisher=Oxford University Press |isbn=978-0-19-517072-6 |pages=25 |language=en}}</ref> The [[Ponte Sant'Angelo]], built during the reign of [[Hadrian]], has five arches each with a span of {{convert|18|m}}.<ref name="troyano" /> A bridge in [[Alcántara]] has piers {{convert|1|m}} wide, {{convert|47|m}} high, and arches with a span of {{convert|1.3|m}}. Another bridge over the Bibey River in [[Galicia (Spain)|Galicia]] has a pier {{convert|1|m}} wide, arches with a {{convert|4.3|m|adj=on}} span, {{convert|6|and|9|m|adj=on}} side arches, and an arch spanning {{convert|18.5|m}}. Wider spans increase the bridge's drainage, reduce water pressure on the [[spandrels]], and reduced the bridge's weight.<ref name="troyano" /> [[Trajan's Bridge]] over the [[Danube]] featured open-spandrel segmental arches made of wood (standing on {{convert|40|m}} high concrete piers). This was to be the longest arch bridge for a thousand years both in terms of overall and individual span length. The longest extant Roman bridge is the {{convert|790|m|adj=on}} [[Puente Romano]] at [[Mérida, Spain|Mérida]].<ref name=":132">{{harvnb|Galliazzo|1995|pp=92, 93 (fig. 39)}}</ref>

=== Stone bridges ===
Roman engineers would begin by laying a foundation for building bridges across moving bodies of water. At first, they used heavy timbers as [[pilings]] in the riverbed, but a later technique involved using [[cofferdam|watertight walls]] to redirect the water and then laying a stone foundation in the area. Work was exclusively done during the [[dry season]] to aid in constructing a foundation. This ensured as many piers as possible were accessible. There is some evidence that to construct bridges rivers were diverted. Trajan might have performed such a practice when constructing his Danube bridge. Roman engineers might have diverted rivers using rudimentary methods and tools. Sometimes dirt was added to the foundation. A bridge's foundation could be built above or below [[water level]]. Building the bridge above water level resulted in a need for a wider span.<ref name="maynard" /><ref name="ruddock" /> Bridge's tunnels and spandrels were designed to decrease the weight of the bridge and function as [[flood arch]]es.<ref name="ruddock" />

[[File:Bender_-_Pons_Aemilius.JPG|thumb|left|[[Pons Aemilius]]]]
The [[Pons Aemilius]] probably had stone piers with wooden roadbeds and arches.<ref name="aldrete" /> They were rebuilt in stone in 142 BC and either extended from the abutments to the [[Pier (architecture)|piers]] or vice versa. Throughout Roman history, brick or stone arches supported bridges' weight.<ref name="maynard" /> Roman engineers built bridges with one long arch instead of several smaller ones. This practice made construction easier, as they only needed to build one arch on land, instead of many in water. Roman arches were semi-circular and used [[voussoir]]s with equal dimensions and [[conic section]]s with equal circumference.<ref name="troyano" /><ref name=":143">{{harvnb|Galliazzo|1994|p=2 (Indice)}}</ref> Later in Roman history arches started to become [[Semicircle|semi-circular]].<ref>{{harvnb|Galliazzo|1995|pp=429–437}}</ref><ref>{{harvnb|O'Connor|1993|p=171}}</ref> Sometimes arches were [[Segmental arch|segmented]], or not semicircular.<ref name="beall" /> The Romans invented this technique. Segmented arches allowed greater amounts of flood water to pass, preventing the bridge from being swept away and allowing it to be lighter. The [[Bridge near Limyra]] in southwestern [[Turkey]] has 26 segmental arches with an average span-to-rise ratio of 5.3:1,<ref>{{harvnb|O'Connor|1993|p=126}}</ref> giving the bridge an unusually flat profile unsurpassed for more than a millennium.<ref name=":153">{{harvnb|O'Connor|1993|p=187ff}}</ref> The late Roman [[Karamagara Bridge]] in [[Cappadocia]] in eastern Turkey may represent the earliest surviving bridge featuring a pointed arch. However, it is now submerged by the [[Keban Dam]].<ref name=":132"/> Roman arches were unable to fit into the arch springings properly, forcing the base of the arches upwards. 

In the [[2nd century]], arches became thinner, and spandrels became flat and pierced with holes.  They were constructed using a wooden frame to hold wedge-shaped blocks in place. Afterwards, the wooden frame was removed, but the weight of the [[Keystone (architecture)|keystone]], the last block to be put in place, held it together.<ref>{{Cite book |last=Uhl |first=Xina M. |url=https://books.google.com/books?id=oLPXDwAAQBAJ&dq=Construction+of+Roman+bridges&pg=PA34 |title=How STEM Built the Roman Empire |date=2019-12-15 |publisher=The Rosen Publishing Group, Inc |isbn=978-1-7253-4154-8 |pages=33–34 |language=en}}</ref> Bridges had [[abutment]]s at each end and piers in the middle, these two design features carrying most of the bridge's weight. Abutments could be constructed in the many [[arch]]es of a bridge, allowing each to be built separately.<ref name="maynard">{{Cite book |last=Maynard |first=Charles W. |url=https://books.google.com/books?id=Za6fFqskPFUC&dq=Bridges+in+Ancient+Rome&pg=PA15 |title=The Technology of Ancient Rome |date=15 January 2006 |publisher=The Rosen Publishing Group, Inc |isbn=978-1-4042-0556-7 |pages=15–21 |language=en |quote=The ends of the bridge called abutments, were built on each side, and piers were situated in the middle. The abutments and piers carried most of the bridge's weight.}}</ref> Piers were usually twenty-six feet thick and [[Framing (construction)|framed]] with [[Starling (structure)|starlings]]. The Karamagara Bridge represents an early example of the use of [[pointed arch]]es.

Roman [[Pier (architecture)|piers]] were thick enough to support the pressure of an arch. Stone arches allowed bridges to have much longer spans.<ref name="dupre" /> Usually, iron clamps covered in [[lead]] were used to build piers. Because of poor performance underwater, Roman piers were often destroyed over time.<ref name="ruddock" /> Bridges that survived to the modern day were often furnished with [[starling (structure)|cut waters]] on the upstream side and a flat downstream face, though some bridges, such as a bridge in [[Chester]], are exceptions.<ref name="ruddock" />

Two [[niche construction|niches]] carrying [[cornice]]s were inserted between [[pilaster]]s. They were then put above the framed starlings. Roman bridges had [[spandrel]]s, between which images of [[dolphin]]s were often inserted.<ref name="whitney" /> They rarely had wide spans and thick piers with [[Bow (watercraft)|bow]]-shaped piers that used small openings to allow for the flow of water. During construction, cranes were used to move materials and lift heavy objects.<ref name=":72">{{Cite book |last1=Arêde |first1=António |url=https://books.google.com/books?id=K0uzDwAAQBAJ&dq=Construction+of+Roman+bridges&pg=PA104 |title=Proceedings of ARCH 2019: 9th International Conference on Arch Bridges |last2=Costa |first2=Cristina |date=2019-10-01 |publisher=Springer Nature |isbn=978-3-030-29227-0 |pages=31–34 |language=en}}</ref> Some bridges had [[Apron (architecture)|aprons]]. They were used to surround piers. Usually, the aprons covered the area of the [[stream bed]] near the bridge.<ref name="ruddock" />

[[Marcus Vipsanius Agrippa]] used [[ashlar]] and bricks to cover the outside of bridges and concrete for [[foundation (engineering)|footings]] and water channels. Ashlar was used because large amounts of wood were needed to [[casting (metalworking)|cast]] the concrete.<ref>{{Cite book |last=Garrison |first=Ervan G. |url=https://books.google.com/books?id=3XuCDwAAQBAJ&dq=History+of+Roman+bridges&pg=PT113 |title=History of Engineering and Technology: Artful Methods |date=2018-12-19 |publisher=Routledge |isbn=978-1-351-44047-9 |language=en}}</ref> [[Travertine]] limestone and [[tuff]] were used to build Roman bridges,<ref name="oleson" /> or they could be made of dry rubble or concrete. Often the building materials varied in [[smoothness]], or [[Rustication (architecture)|rustication]]. Other bridges were made of [[Boss (architecture)|bossed]] limestone combined with cornices, voussoirs and slabs. Sometimes [[bedrock]], [[buttress]]es, and [[Vault (architecture)|vaults]] were used to construct bridges.<ref name="oleson" /> Bridges built in Iberia tended to have cylindrical vault geometry.<ref name=":72" /> In the first half of the 2nd century BC, blocks of stone held together with iron [[Sleeve coupling|clamps]] were used to aid in the construction of bridges.

=== Brick bridges ===
Although [[Roman brick]]s were used to build many bridges, they were far more commonly used to build aqueducts. Bridges built from bricks were rare as bricks often failed to survive [[erosion]].<ref name=":112">{{Cite book |last1=Yegül |first1=Fikret |url=https://books.google.com/books?id=G8CkDwAAQBAJ&dq=Brick+bridges+Roman&pg=PA153 |title=Roman Architecture and Urbanism: From the Origins to Late Antiquity |last2=Favro |first2=Diane |date=2019-09-05 |publisher=Cambridge University Press |isbn=978-0-521-47071-1 |pages=153 |language=en}}</ref> The brick bridges that were built were generally used by the [[Military of ancient Rome|military]], and they used construction techniques called ''[[opus vittatum]]'' and ''[[opus mixtum]]'', the latter alternating rows of bricks in ''[[opus reticulatum]]''.<ref name="bove" /> Examples are bridges in [[Carmona, Spain|Carmona]], [[Palomas, Badajoz|Palomas]], [[Extremadura]], and the [[Ponte del Chianche|Ponte della Chianche]] in Italy. One brick bridge in [[Ticino]], [[Switzerland]], has stone arches and brick spandrels.<ref name="troyano" /> Bricks were sometimes used to create parts of bridges, such as [[Vault (architecture)|vaults]], piers with [[welding joint]]s, and brick and [[Mortar and pestle|mortar]] [[rubble]].<ref name="beall" />

=== Wooden bridges ===
[[File:Il_ponte_di_Cesare_sul_Reno.jpg|thumb|left|[[Caesar's Rhine bridges|Caesar's Rhine Bridge]]]]
Early Roman bridges were wooden, including one constructed by [[Apollodorus of Damascus|Apollodorus]] and the Pons Sublicius, the oldest bridge in ancient Rome, and they were probably common across northern Europe and the [[Tyrrhenian Sea|Tyrrhenian coast]];<ref name="ruddock" /> however, because of their lack of durability few have survived to the modern day.<ref>{{Cite book |last1=Glick |first1=Thomas F. |url=https://books.google.com/books?id=77y2AgAAQBAJ&dq=Brick+bridges+Roman&pg=PA103 |title=Medieval Science, Technology, and Medicine: An Encyclopedia |last2=Livesey |first2=Steven |last3=Wallis |first3=Faith |date=2014-01-27 |publisher=Routledge |isbn=978-1-135-45932-1 |pages=103 |language=en}}</ref> These bridges were supported by wooden [[Trestle support|trestles]] spanned by horizontal timbers and reinforced with [[strut]]s, and they were possibly [[cantilever]]ed. In order to simplify the process of cutting trees, multiple shorter timbers were used.<ref name="whitney" /> Wooden poles were driven into the ground, and flat pieces of timber laid across them to create a flat surface.<ref name="mcgeough">{{Cite book |last=McGeough |first=Kevin M. |url=https://books.google.com/books?id=tKzvK5YbCJYC&dq=Construction+of+Roman+bridges&pg=PA213 |title=The Romans: An Introduction |date=2009-03-26 |publisher=OUP USA |isbn=978-0-19-537986-0 |pages=213 |language=en}}</ref> 

Other early techniques used to build wooden bridges involved [[barge]]s, sometimes they were [[moored]] side by side. Workmen would raise weights, sometimes by rope, then it would fall down onto the piles. This method of construction, called [[pile driving]], was necessary for wooden bridges to properly function. Because this technique created [[cofferdam]]s, which are enclosures build to pump water out of an area.<ref>Chisholm, Hugh, ed. (1911). "[[wikisource:1911 Encyclopædia Britannica/Cofferdam|Cofferdam]]" . ''[[Encyclopædia Britannica Eleventh Edition|Encyclopædia Britannica]]''. Vol. 6 (11th ed.). Cambridge University Press. p. 649.</ref> The base for the foundation of the bridge would be put in this area.<ref name="ruddock" /> Cofferdams were constructed of many piles held together. It is possible the piles were interconnected, likely to improve positioning, [[Waterproofing|waterproofness]], or both. Cofferdams would have been sealed with packed clay.<ref name="ruddock" /> The cofferdams also needed to be consistently dry. In order to achieve this, engineers would use tools such as buckets to drain the water.<ref name="ruddock" /> Wooden bridges could be burned to stop an attacker, or dismantled quickly.<ref name="oleson" /><ref>{{Cite book |last=Landart |first=Paula |url=https://books.google.com/books?id=S-VxBAAAQBAJ&dq=Bridges+in+Ancient+Rome&pg=PA46 |title=Finding Ancient Rome: Walks in the city |date=5 December 2021 |publisher=Paula Landart |pages=45–46 |language=en}}</ref> For example, according to [[Livy]], during a battle against the [[Sabines]] the Romans set one of their wooden bridges on fire, driving the enemy back.<ref>{{Cite book |last=Livius |first=Titus |url=https://files.romanroadsstatic.com/materials/romans/historians/Livy_Early_History_Rome_1-0.pdf |title=Early History of Rome |pages=43}}</ref> Other early wooden bridges used [[post and lintel]] construction.
[[File:Roman Pontoon Bridge, Column of Marcus Aurelius, Rome, Italy.jpg|thumb|Roman legionaries crossing the Danube River by [[pontoon bridge]], as depicted in a relief on the [[Column of Marcus Aurelius]]]]

=== Pontoon bridges ===

[[Pontoon bridge]]s were built by laying boats from side to side across a river.<ref name="mcgeough" /><ref name="bunson" /> During [[Julius Caesar]]'s [[Gallic Wars|campaign]] in [[Germania|Germany]], he built [[Caesar's Rhine bridges|bridges]] by driving wooden piles into the [[stream bed]] from floating platforms and fixing beams at [[right angle]]s across them to create trestles. [[Trajan]] built another bridge supported by stone during the [[Trajan's Dacian Wars|Dacian Wars]].<ref name="corbishley" /> Roman engineers gradually developed new techniques to build bridges, such as oval-shaped bases and pierced bases to facilitate the movement of water. Many bridges would have [[marble]] [[relief]]s or [[carving]]s, but these bridges were likely used exclusively by [[Roman Constitution|government officials]] because of the difficulty and expense of carving marble artwork.

== Typology ==
[[File:Ponte Quattro Capi.jpg|thumb|left|[[Pons Fabricius]] in Rome]]
There were three major types of Roman bridges. These were wooden, pontoon, and stone bridges.  A list of Roman bridges compiled by the engineer Colin O'Connor features 330 [[List of Roman bridges#Masonry bridges|stone bridges]] for traffic, 34 [[List of Roman bridges#Timber and stone pillar bridges|timber bridges]] and 54 [[List of Roman bridges#Aqueduct bridges|aqueduct bridges]], a substantial number still standing and even used to carry vehicles.<ref name=":153"/> A more complete survey by the Italian scholar Vittorio Galliazzo found 931 Roman bridges, mostly of stone, in as many as 26 different countries (including former [[Yugoslavia]]; see right table).<ref name=":143"/> A segmental arch is an arch that is less than a semicircle.<ref name="beall" /> The Romans built both single spans and lengthy multiple-arch [[Roman aqueducts|aqueducts]], such as the [[Pont du Gard]] and [[Segovia Aqueduct]]. Their bridges often had flood openings in the piers, e.g. in the [[Pons Fabricius]] in Rome (62 BC), one of the world's oldest major bridges still standing.

There were two main types of wooden bridge in Britain. Small timber bridges with [[girder]]s, and large ones made of stone and wood. Throughout the rest of the Roman  world, except for northern Europe, arched bridges made of stone were common. This was likely due to the climate and rivers of the regions. Rivers were much calmer and water levels were lower in the southern parts of the Empire. This ensured foundations were easy to construct. While in the northern parts it was much harder to lay down foundations due to the high water level, muddy water, and substantial waterflow.<ref>{{Cite book |last=Harrison |first=David Featherstone |url=https://books.google.com/books?id=AE4VDAAAQBAJ&dq=types+of+Roman+bridges&pg=PA99 |title=The Bridges of Medieval England: Transport and Society, 400–1800 |date=2004 |publisher=Oxford University Press |isbn=978-0-19-927274-7 |pages=99 |language=en}}</ref>

== Location ==
{| class="wikitable sortable mw-collapsible"
|+The location of all 961 known Roman bridges<ref>Galliazzo 1994, p. 2 (Indice). Galliazzo's survey excludes Late Roman or [[Byzantine]] structures.

</ref>
!Europe
!830
!Asia
!74
!Africa
!57
|-
|Italy
|460
|Turkey
|55
|Tunisia
|33
|-
|Spain
|142
|Syria
|7
|Algeria
|18
|-
|France
|72
|Jordan
|5
|Libya
|5
|-
|Germany
|30
|Lebanon
|4
|
|
|-
|United Kingdom
|29
|Israel
|2
|
|
|-
|Portugal
|14
|Iran 
|1
|
|
|-
|Yugoslavia
|13
|
|
|
|
|-
|Switzerland
|11
|
|
|
|
|-
|Greece
|10
|
|
|
|
|-
|Netherlands
|4
|
|
|
|
|-
|Bulgaria
|3
|
|
|
|
|-
|Luxemburg
|3
|
|
|
|
|-
|Albania
|2
|
|
|
|
|-
|Austria
|2
|
|
|
|
|-
|Belgium
|2
|
|
|
|
|-
|Romania
|2
|
|
|
|
|-
|Hungary
|1
|
|
|
|
|}

== ''Opus pontis'' ==
[[File:Bridge Alcantara.JPG|thumb|The [[Alcántara Bridge]]]]
The costs of building and repairing bridges, known as ''opus pontis'' ("bridge work"), were the responsibility of multiple local municipalities. Their shared costs prove Roman bridges belonged to the region overall, and not to any one town (or two, if on a border). The [[Alcántara Bridge]] in [[Lusitania]], for example, was built at the expense of 12 local municipalities, whose names were added on an inscription.<ref>{{cite journal |last1=Frothingham |first1=A.I. |date=1915 |title=The Roman Territorial Arch |url=https://books.google.com/books?id=xX1JAAAAYAAJ&pg=PA172 |journal=American Journal of Archaeology |language=en |publisher=Macmillan Company |volume=14 |issue=19 |pages=159, 172}}</ref> Later, in the [[Roman Empire]], the local lords of the land had to pay tithes to the empire for ''opus pontis''.<ref>{{cite book |last1=James-Raoul |first1=Danièle |url=https://books.google.com/books?id=5Pyh1YlfFCIC&pg=PA201 |title=Les ponts au Moyen Âge |last2=Thomasset |first2=Claude |date=2006 |publisher=Presses Paris Sorbonne |isbn=9782840503736 |page=201 |language=fr |access-date=15 July 2017}}</ref><ref>{{cite book |last1=Gillespie |first1=Donald S. |url=https://books.google.com/books?id=2-McCgAAQBAJ&pg=PA27 |title=Le Beau Dieu |date=2015 |publisher=Holy Fire Publishing |isbn=9781603835084 |page=27 |language=en |access-date=15 July 2017}}</ref> The [[Anglo-Saxons]] continued this practice with ''bricg-geworc'', a literal translation of ''opus pontis''.<ref>{{cite book |last1=Bosworth |first1=Joseph |url=https://books.google.com/books?id=oXlii1KgDngC&q=opus+pontis&pg=PA125 |title=An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth ... |date=1882 |publisher=Clarendon Press |page=125 |language=en |access-date=15 July 2017}}</ref>

== Examples ==
Built in 142 BC, the [[Pons Aemilius]], later named Ponte Rotto (broken bridge), is the oldest Roman stone bridge in [[Rome]], with only one surviving arch and pier. However, evidence suggests only the [[abutment]] is original to the 2nd century BC while the arch and pier perhaps date to a reconstruction during the reign of [[Augustus]] (27 BC – 14 AD).<ref>Platner, Samuel Ball, ''A Topographical Dictionary of Ancient Rome'', ed. Ashby, Thomas, London: Oxford University Press, 1929 [Thayer, Bill (17 May 2020) [https://penelope.uchicago.edu/Thayer/E/Gazetteer/Places/Europe/Italy/Lazio/Roma/Rome/_Texts/PLATOP*/Pons_Aemilius.html "Pons Aemilius"], [[University of Chicago]], Accessed 9 June 2021]</ref> The Pons Fabricius, built in 62 BC during the late Republic, is the oldest Roman bridge that is still intact and in use.<ref name="Taylor20002">{{cite book |last=Taylor |first=Rabun M. |url=https://books.google.com/books?id=rqMGZr4yAkQC&pg=PA141 |title=Public Needs and Private Pleasures: Water Distribution, the Tiber River and the Urban Development of Ancient Rome |publisher=L'ERMA di BRETSCHNEIDER |year=2000 |isbn=978-88-8265-100-8 |pages=141–}}</ref> The largest Roman bridge was [[Trajan's Bridge]] over the lower [[Danube]], constructed by [[Apollodorus of Damascus]], which remained for over a millennium the longest bridge to have been built both in terms of overall and span length.<ref>{{Citation |title=Where are the Greatest Bridges of Ancient Rome? |url=https://www.youtube.com/watch?v=o-ncxDpuAE8 |access-date=2023-09-05 |language=en}}</ref>

=== Large river bridging ===
Roman engineers built stone arch or stone pillar bridges over all major rivers of the Empire save two: the [[Euphrates]], which lay at the frontier in the [[Roman–Persian Wars]], and the [[Nile]], the longest river in the world, which was bridged as late as 1902 by the British [[Old Aswan Dam]].<ref>{{harvnb|O'Connor|1993|pp=193–202 (Appendices A and B)}}

[[Help:Category|Categories]]</ref> The largest rivers to be spanned by solid bridges by the Romans were the [[Danube]] and the [[Rhine]], [[List of rivers of Europe|the two largest European rivers]] west of the [[Eurasian Steppe]]. The lower Danube was crossed by least two ([[Trajan's Bridge]], [[Constantine's Bridge (Danube)|Constantine's Bridge]]) and the middle and lower Rhine by four different bridges (the [[:de:Römerbrücke (Mainz)|Roman Bridge at Mainz]], [[Caesar's Rhine bridges]], the [[:de:Römische Brücken in Koblenz|Roman Bridge at Koblenz]], the [[:de:Römerbrücke (Köln)|Roman Bridge at Cologne]]). For rivers with strong currents and to allow swift army movements, [[pontoon bridge]]s were also routinely employed.<ref>{{harvnb|O'Connor|1993|pp=133–139}}</ref> Judging by the distinct lack of records of pre-modern solid bridges spanning larger rivers,<ref name="troyano" /> the Roman feat appears to be unsurpassed anywhere in the world until into the 19th century.

== See also ==
{{Portal|Ancient Rome}}
* [[List of Roman bridges]]
* [[Bridges in Rome]]
* [[List of ancient architectural records#Bridges|Record-holding bridges in antiquity]]
* [[Roman architecture]]
* [[Roman architectural revolution]]

== Footnotes==
{{reflist}}

== References ==
*Fuentes, Manuel Durán: ''La construcción de puentes romanos en Hispania'', Xunta de Galicia, Santiago de Compostela 2004, {{ISBN|978-84-453-3937-4}}
*{{Citation
 | last = Fernández Troyano
 | first = Leonardo 
 | title = Bridge Engineering. A Global Perspective
 | publisher = Thomas Telford Publishing
 | location = London
 | year = 2003
 | isbn = 0-7277-3215-3
}}
*{{Citation
 | last = Galliazzo
 | first = Vittorio
 | title = I ponti romani
 | volume = 1
 | year = 1995
 | publisher = Edizioni Canova
 | location = Treviso
 | isbn = 88-85066-66-6
}}
*{{Citation
 | last = Galliazzo
 | first = Vittorio
 | title = I ponti romani. Catalogo generale
 | volume = 2
 | year = 1994
 | publisher = Edizioni Canova
 | location = Treviso
 | isbn = 88-85066-66-6
}}
*{{Citation|first=Piero |last=Gazzola|title=Ponti romani. Contributo ad un indice sistematico con studio critico bibliografico|location=Florence |year=1963}}
*{{Citation
 | last = O'Connor
 | first = Colin 
 | title = Roman Bridges
 | publisher = Cambridge University Press
 | year = 1993
 | isbn = 0-521-39326-4
}}

== External links ==
{{Commons category|Ancient Roman bridges|Roman bridges}}
*[https://web.archive.org/web/20080528061612/http://traianus.rediris.es/ Traianus] - Technical investigation of Roman public works
*[http://www.iath.virginia.edu/rome/Journal2TaylorNew.pdf The Waters of Rome: Tiber River Bridges and the Development of the Ancient City of Rome]
*[https://www.livius.org/pn-po/pontes_longi/pontes_longi.html Livius.org: Pontes longi] – Roman bog bridges

{{Roman bridges|state=collapsed}}
{{Ancient Tiber Bridges|state=collapsed}}
{{Ancient Rome topics}}
{{Authority control}}

[[Category:Ancient Roman architecture]]
[[Category:Roman bridges| ]]