A through arch bridge , also known as a through-type arch bridge , is a bridge that is made from materials such as steel or reinforced concrete, in which the base of an arch structure is below the deck but the top rises above it. It can either be lower bearing or mid-bearing . Thus, the deck is within the arch, and cables or beams that are in tension suspend the central part of the deck from the arch.
20-668: Chirk Aqueduct is a 70-foot (21 m) high and 710-foot (220 m) long navigable aqueduct that carries what is now the Llangollen Canal across the Ceiriog Valley near Chirk , on the England-Wales border , spanning the two countries. The aqueduct was designed by civil engineer Thomas Telford for the Ellesmere Canal . The resident engineer was M. Davidson who also acted as resident engineer on
40-727: A larger cross-section of water than most water-supply aqueducts . Roman aqueducts were used to transport water and were created in Ancient Rome. The 662-metre (2,172 ft) long steel Briare aqueduct carrying the Canal latéral à la Loire over the River Loire was built in 1896. It was ranked as the longest navigable aqueduct in the world for more than a century, until the Magdeburg Water Bridge in Germany took
60-620: A number of Telford's other works. The foundation stone was laid on 17 June 1796 and it was completed in 1801. It has a cast iron trough within which the water is contained. The masonry walls hide the cast iron interior. The aqueduct followed Telford's innovative Longdon-on-Tern Aqueduct on the Shrewsbury Canal , and was a forerunner of the Pontcysyllte Aqueduct , also on the Llangollen Canal. The aqueduct
80-467: A through arch does not change the proportions or size of the arch: a large span will still require a tall arch, although this can now reach any height above the deck without obstructing traffic. The arch may also reach downwards at its sides, to either reach strong foundations or to place the roadway at a convenient height for spanning a deep valley from a plateau above. The Tyne Bridge demonstrates both of these advantages. A well-known example of this type
100-518: Is constructed in place or lifted into position. In some cases, this type of arch has been created by constructing cantilevers from each side, with the shoreside ends bolted securely down into heavy piers. The incomplete channel ends are then constructed toward each other and either filled by construction or by lifting a prefabricated center section. This type of construction was used in the Sydney Harbour Bridge illustrated above, with
120-399: Is not practical to support the arch from beneath during construction. In modern construction, temporary towers are erected and supported by cables anchored in the ground. Temporary cables fly from each side to support arch segments as they are constructed. When the arches are almost complete a jacking bridge is placed over or beneath the gap to force the arches apart, whence the final section
140-1031: Is the Sydney Harbour Bridge in Australia, which is based on the Hell Gate Bridge in New York City . Other bridges include the Chaotianmen Bridge in China, the world's longest through arch bridge; Tyne Bridge of Newcastle upon Tyne ; the Bayonne Bridge that connects New York City to New Jersey , which is longer than the Sydney Harbour Bridge; the Ahwaz White Bridge ; the Bourne Bridge and Sagamore Bridge , smaller, near-twin bridges over
160-423: Is true for the entire Llangollen Canal, a steady current flows in the aqueduct with the narrow cross-section of the aqueduct's trough amplifying this flow. Navigable aqueduct Navigable aqueducts (sometimes called navigable water bridges ) are bridge structures that carry navigable waterway canals over other rivers, valleys, railways or roads. They are primarily distinguished by their size, carrying
180-840: The Cape Cod Canal ; the Pennybacker Bridge in Austin , Texas and as the Hernando de Soto Bridge in Memphis, Tennessee . Wylam Railway Bridge is an early through arch bridge upstream of the Tyne Bridge. The through arch bridge usually consists of two ribs, although there are examples like the Hulme Arch Bridge of through arches with a single rib. When the two arches are built in parallel planes,
200-494: The foundations for the bridge. Arch bridges generate large side thrusts on their footings and so may require a solid bedrock foundation. Flattening the arch shape to avoid the humpback problem, such as for Brunel's Maidenhead bridge , increases this side thrust. It is often impossible to achieve a flat enough arch, simply owing to the limitations of the foundations – particularly in flat country. Historically, such bridges often became viaducts of multiple small arches. With
220-493: The availability of iron or concrete as structural materials, it became possible to construct a through arch bridge : a bridge where the deck does not have to be carried over the top of the arch. This requires a structure that can both support the deck from the arch by tension rods, chains or cables and allow a gap in the arch, so the deck can pass through it. The first of these in particular cannot be achieved with masonry construction and requires wrought iron or steel. The use of
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#1732773068573240-491: The deliberate tension member that is the key to a tied-arch. Although visually similar, tied- and untied- through-arch bridges are quite distinct structurally and are unrelated in how they distribute their loads. In particular, cast iron bridges such as the Stanley Ferry Aqueduct may resemble tied-arch bridges, but as cast iron is weak in tension they are not structurally a tied arch. In some locations it
260-466: The ironwork for the aqueduct. Originally built with iron plates only at the base of the trough, iron side plates were added to the aqueduct in 1870 to alleviate leakage. The Chirk Tunnel starts at the north end of the Chirk Aqueduct, allowing the canal to continue on towards Llangollen. Chirk Railway Viaduct was built later alongside the aqueduct. It is slightly higher than the aqueduct. As
280-432: The proportions of the arch remain similar no matter what the size: wider arches are thus required to be taller arches. For a semi-circular arch, the height is half of the span. Bridges across deep, narrow gorges can have their arch placed entirely beneath a flat roadway, but bridges in flatter country rise above their road approaches. A wide bridge may require an arch so tall as to become a significant obstacle and incline for
300-494: The roadway. Small bridges can be hump-backed , but larger bridges such as the Old Bridge, Pontypridd may become so steep as to require steps, making their use for wheeled traffic difficult. Railways also find arched bridges difficult as they are even less tolerant of inclines. Where simple arched bridges are used for railways on flat terrain the cost of building long approach embankments may be considerable. Further issues are
320-502: The structure is a parallel rib arch bridge. When the two arch ribs lean together and shorten the distance between the arches near the top, the span is a basket handle arch bridge. Many tied-arch bridges are also through-arch bridges. As well as tying the side-loads of the arch, the tension member is also at a convenient height to form the bridge deck, as for a through-arch. The converse is not true: through-arch bridges do not imply that they are tied-arch bridges, unless they also provide
340-486: The title in the early 21st century. Early aqueducts such as the three on the Canal du Midi had stone or brick arches, the longest span being 18.3 metres (60 ft) on the Cesse Aqueduct , built in 1690. But, the weight of the construction to support the trough with the clay or other lining to make it waterproof made these structures clumsy. In 1796 Longdon-on-Tern Aqueduct , the first large cast iron aqueduct
360-596: The world. Other cast-iron aqueducts followed, such as the single-span Stanley Ferry Aqueduct on the Calder and Hebble Navigation in 1839, with its innovative 50-metre (160 ft) through arch design. There were 32 navigable aqueducts on the Erie Canal , constructed 1817–1825 in New York State , United States. Through arch bridge For a specific construction method, especially for masonry arches,
380-588: Was briefly the tallest navigable one ever built, and it now is Grade II* listed in both England and Wales. It forms part of the Pontcysyllte Aqueduct World Heritage Site . The aqueduct consists of ten arches, each with a span of 40 feet (12 m). The water level is 65 feet (20 m) above the ground and 70 feet (21 m) above the River Ceiriog. The stone work is yellow sandstone. William Hazledine provided
400-519: Was built by Thomas Telford at Longdon-on-Tern on the Shrewsbury Canal . It has a total length of 57 metres (187 ft) across three intermediate piers. Within ten years Telford had completed the far more ambitious Pontcysyllte Aqueduct in Wales on the Llangollen Canal over the River Dee valley, with a total length 307 metres and a height of 38 metres, making it the tallest navigable aqueduct in
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