Editing Ancient Roman architecture (section)

=== Bridges ===
{{Main|Roman bridge}}
{{further|List of Roman bridges}}
[[File:Roman_Bridge_of_Mérida_2023.jpg|thumb|[[Puente Romano, Mérida|Puente Romano]] over the Guadiana River at [[Mérida, Spain]]]]
Roman bridges, built by [[ancient Romans]], were the first large and lasting bridges built.{{sfn|O'Connor|1993|p=1}} Roman bridges were built with stone and had the [[arch]] as the basic structure. Most used [[Roman concrete|concrete]] as well, which the Romans were the first to use for bridges.

Roman arch bridges were usually [[semicircular]], although a few were [[circular segment|segmental]] (such as [[Alconétar Bridge]]). A segmental arch is an arch that is less than a semicircle.<ref>{{cite web|url=http://imgs.ebuild.com/woc/M880252.pdf |title=Designing the segmental arch |last=Beall |first=Christine |year=1988 |publisher=ebuild.com |access-date=8 May 2010}}</ref> The advantages of the segmental arch bridge were that it allowed great amounts of flood water to pass under it, which would prevent the bridge from being swept away during floods and the bridge itself could be more lightweight. Generally, Roman bridges featured wedge-shaped primary arch stones ([[voussoir]]s) of the same in size and shape. The Romans built both single spans and lengthy multiple arch [[Roman aqueducts|aqueducts]], such as the [[Pont du Gard]] and [[Segovia Aqueduct]]. Their bridges featured from an early time onwards 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. Roman engineers were the first and until the [[Industrial Revolution]] the only ones to construct bridges with [[Roman concrete|concrete]], which they called ''opus caementicium''. The outside was usually covered with brick or ashlar, as in the Alcántara bridge.

The Romans also introduced segmental arch bridges into bridge construction. The 330&nbsp;m long [[Limyra Bridge]] in southwestern [[Turkey]] features 26 segmental arches with an average span-to-rise ratio of 5.3:1,{{sfn|O'Connor|1993|p=126}} giving the bridge an unusually flat profile unsurpassed for more than a millennium. [[Trajan's bridge]] over the [[Danube]] featured open-spandrel segmental arches made of wood (standing on 40&nbsp;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, while the longest extant Roman bridge is the 790&nbsp;m long [[Puente Romano]] at [[Mérida, Spain|Mérida]].