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25-651: The Ravenna Bridge is a 58-metre (190 ft) high and 225-metre (738 ft) long railway viaduct on the Höllental Railway line in the Black Forest , in Breitnau , Breisgau-Hochschwarzwald , Baden-Württemberg , Germany . The bridge crosses the Ravenna Gorge that ends in the upper Höllental valley, and has a grade of 12 metres (39 ft). The origin of the name most likely comes from

50-543: A landscape, usually by bridging a river valley or other eroded opening in an otherwise flat area. Often such valleys had roads descending either side (with a small bridge over the river, where necessary) that become inadequate for the traffic load, necessitating a viaduct for "through" traffic. Such bridges also lend themselves for use by rail traffic, which requires straighter and flatter routes. Some viaducts have more than one deck, such that one deck has vehicular traffic and another deck carries rail traffic. One example of this

75-566: A length today of only 47 metres (154 ft). The bridge was exploded by German forces near the end of the World War II . It was re-built in 1947–48, under the direction of French occupying forces and with the use of German prisoners of war obligated to undertake compulsory labour, so that large quantities of logs from the Black Forest that had to be delivered as war reparations could be transported out. Viaduct A viaduct

100-607: A repurposed rail viaduct provides a garden promenade on top and workspace for artisans below. The garden promenade is called the Coulée verte René-Dumont while the workspaces in the arches below are the Viaduc des Arts . The project was inaugurated in 1993. Manhattan's High Line , inaugurated in 2009, also uses an elevated train line as a linear urban park . In Indonesia viaducts are used for railways in Java and also for highways such as

125-627: Is a 19th-century derivation from an analogy with ancient Roman aqueducts . Like the Roman aqueducts , many early viaducts comprised a series of arches of roughly equal length. The longest viaduct in antiquity may have been the Pont Serme which crossed wide marshes in southern France. At its longest point, it measured 2,679 meters with a width of 22 meters. Viaducts are commonly used in many cities that are railroad hubs , such as Chicago, Birmingham, London and Manchester . These viaducts cross

150-472: Is a specific type of bridge that consists of a series of arches, piers or columns supporting a long elevated railway or road. Typically a viaduct connects two points of roughly equal elevation, allowing direct overpass across a wide valley, road, river, or other low-lying terrain features and obstacles. The term viaduct is derived from the Latin via meaning "road", and ducere meaning "to lead". It

175-507: Is built across land rather than water, the space below the arches may be used for businesses such as car parking, vehicle repairs, light industry, bars and nightclubs. In the United Kingdom, many railway lines in urban areas have been constructed on viaducts, and so the infrastructure owner Network Rail has an extensive property portfolio in arches under viaducts. In Berlin the space under the arches of elevated subway lines ( S-Bahn )

200-908: Is the Prince Edward Viaduct in Toronto, Canada, that carries motor traffic on the top deck as Bloor Street , and metro as the Bloor-Danforth subway line on the lower deck, over the steep Don River valley . Others were built to span settled areas, crossing over roads beneath—the reason for many viaducts in London. Viaducts over water make use of islands or successive arches. They are often combined with other types of bridges or tunnels to cross navigable waters as viaduct sections, while less expensive to design and build than tunnels or bridges with larger spans, typically lack sufficient horizontal and vertical clearance for large ships. See

225-407: Is used for several different purposes, including small eateries or bars. Elevated expressways were built in major cities such as Boston ( Central Artery ), Los Angeles, San Francisco, Seoul , Tokyo and Toronto ( Gardiner Expressway ). Some were demolished because they were unappealing and divided the city. In other cases, viaducts were demolished because they were structurally unsafe, such as

250-542: The Chesapeake Bay Bridge-Tunnel . The Millau Viaduct is a cable-stayed road-bridge that spans the valley of the river Tarn near Millau in southern France. It opened in 2004 and is the tallest vehicular bridge in the world, with one pier's summit at 343 metres (1,125 ft). The viaduct Danyang–Kunshan Grand Bridge in China was the longest bridge in the world as of 2011 . Where a viaduct

275-645: The Embarcadero Freeway in San Francisco, which was damaged by an earthquake in 1989. However, in developing nations such as Thailand ( Bang Na Expressway , the world's longest road bridge ), India ( Delhi-Gurgaon Expressway ), China, Bangladesh, Pakistan, and Nicaragua, elevated expressways have been built and more are under construction to improve traffic flow, particularly as a workaround of land shortage when built atop surface roads. Other uses have been found for some viaducts. In Paris, France,

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300-634: The Jakarta Inner Ring Road . In January 2019, the Alaskan Way Viaduct in Seattle was closed and replaced with a tunnel after several decades of use because it was seismically unsafe. Prince Edward Viaduct The roadway has five lanes (three eastbound and two westbound) with a bicycle lane in each direction. The subway level connects Broadview station in the east with Castle Frank and Sherbourne stations to

325-461: The French ravin for gorge. The first structure was completed in 1885 and consisted of a steel cantilever span that rested on three mortared sandstone block pillars. The bridge had a slight curve, and trains were limited to a speed of 15 kilometres per hour (9 mph) and an axle load of 16 tonnes (16 long tons ). Heavier locomotives and faster speeds led to the construction in 1926–27 of

350-730: The Prince Edward Viaduct became a magnet for suicide , falling bodies posing risk to the traffic underneath. With nearly 500 suicides by 2003, the viaduct ranked as the most fatal standing structure in Canada and the second most in North America, after the Golden Gate Bridge in San Francisco . At its peak in 1997, the suicide rate averaged one person every 22 days. In 1957, a child also climbed onto

375-544: The arches, which transfer the load to the arches themselves. Finally, the arches transfer their load through large hinges to a concrete pier and eventually to the ground. Steel was provided by Dominion Bridge Company . In addition to the Don River , the Don Valley Parkway , and Bayview Avenue , two railway lines, an electrical transmission line and a bicycle trail all pass under the bridge spans. Over time,

400-400: The current structure, a mortared stone viaduct with nine arches and an arch span of 20 metres (66 ft), which also had the effect of straightening the railway line. The old bridge was then demolished, although the old abutments are still visible. The Ravenna Tunnel that follows immediately after the bridge was originally 85 metres (279 ft) long. It was partially cut open and thus has

425-465: The east side of the Don Valley. Designed by Edmund W. Burke , the Prince Edward Viaduct is a three hinged concrete-steel arch bridge with a total span of 494 metres (1,620 feet), at 40 metres (131 feet) above the Don Valley. The bridge consists of a deck made of transverse beams and I-girders, which transfer load to column supports. The column supports then transfer the load to the trusses within

450-498: The large railroad yards that are needed for freight trains there, and also cross the multi-track railroad lines that are needed for heavy rail traffic. These viaducts provide grade separation and keep highway and city street traffic from having to be continually interrupted by the train traffic. Likewise, some viaducts carry railroads over large valleys, or they carry railroads over cities with many cross-streets and avenues. Many viaducts over land connect points of similar height in

475-688: The lower deck eventually proved to save millions of dollars when the Toronto Transit Commission 's Bloor–Danforth subway opened in 1966. The Rosedale Valley phase was not used for the subway, as the curve between each phase, as well as the curve to the west at Parliament Street, was considered too sharp for the subway. For this reason, a separate concrete bridge was built over the Rosedale Valley, just west of Castle Frank station . The Prince Edward Viaduct resulted in more rapid development of those portions of Toronto lying on

500-502: The planned lighting to be installed on the top horizontal member. The lighting installation was completed in July 2015. The Luminous Veil received in 1999 a Canadian Architect Award of Excellence. A 2010 study found that though the barrier prevented suicide attempts from the viaduct, overall rates of suicide by jumping for the City of Toronto have not changed since its construction. However,

525-502: The railing and fell accidentally while walking along it but survived. People who have survived the jump have had severe consequences including paralysis , organ damage, broken bones and lifelong pain. Most think that jumping will lead to an instant death but for many death is not instant. The suicides and safety risks prompted the construction of a barrier in 2003, though it was first approved by Toronto City Council in 1998 and delayed because of concerns about funding; during that time,

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550-403: The viaduct was the site of an estimated 48 to 60 suicides. The council originally approved a CA$ 2.5 million budget. However, the minimum bid for construction was CA$ 5.5 million . Council eventually endorsed a fundraising campaign to raise the remainder of the money. Construction was completed in 2003 at the cost of CA$ 5.5 million , with CA$ 2.5 million coming from taxpayers. The barrier

575-443: The west. Referendums on the construction of the Prince Edward Viaduct were held in Toronto in every year from 1910 to 1913, with residents voting against its construction in 1912 by 59 votes and in favour in 1913 by 9236 votes. The projected cost of its construction increased from CA$ 759,000 in 1910 to CA$ 2.5 million in 1913; its final cost was CA$ 2,480,349.05 ($ 43.8 million in 2023 dollars ). Upon its completion in 1918, it

600-598: Was called the Luminous Veil . Designed by architect Dereck Revington and engineers at Halcrow Yolles and completed in 2003, the Luminous Veil consists of over 9,000 steel rods, 12.7 cm (5.0 in) apart and five metres (16 ft) high, stretched to cantilevered girders. The tensile structure was difficult to analyze and required several tests at the University of Toronto. Initially, cost prohibited

625-447: Was named for Prince Edward, Prince of Wales (later King Edward VIII ). The viaduct was designed to facilitate mass transit ; its upper deck accommodated streetcars , while both the Don Valley phase and the Rosedale Valley phase included a lower deck for rail transport , controversial at the time because of its high additional cost. The bridge's designer and the commissioner of public works, R.C. Harris , were able to have their way and

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