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69-613: The Crooked River High Bridge is a steel arch bridge that spans the Crooked River gorge in Jefferson County, Oregon . The bridge was designed by Conde McCullough and was completed in 1926. Shortly after its completion, Oregon State Highway Division created the Peter Skene Ogden Park just to the south of the bridge. The bridge has a total length of 464 feet (141 m) with a main span of 330 feet (100 m). The deck

138-505: A deck arch bridge. Any part supported from arch below may have spandrels that are closed or open. The Sydney Harbour Bridge and the Bayonne Bridge are a through arch bridge which uses a truss type arch. Also known as a bowstring arch, this type of arch bridge incorporates a tie between two opposite ends of the arch. The tie is usually the deck and is capable of withstanding the horizontal thrust forces which would normally be exerted on

207-458: A greater passage for flood waters. Bridges with perforated spandrels can be found worldwide, such as in China ( Zhaozhou Bridge , 7th century). Greece ( Bridge of Arta , 17th century) and Wales ( Cenarth Bridge , 18th century). In more modern times, stone and brick arches continued to be built by many civil engineers, including Thomas Telford , Isambard Kingdom Brunel and John Rennie . A key pioneer

276-511: A hypothetical Thracian * Donaris . The Proto-Indo-European root of this presumed name is related to the Iranic word " don- "/" dan- ", while the supposed suffix -aris is encountered in the ancient name of the Ialomița River , Naparis , and in the unidentified Miliare river mentioned by Jordanes in his Getica . Gábor Vékony says that this hypothesis is not plausible, because

345-448: A quantity of fill material (typically compacted rubble) above the arch in order to increase this dead-weight on the bridge and prevent tension from occurring in the arch ring as loads move across the bridge. Other materials that were used to build this type of bridge were brick and unreinforced concrete. When masonry (cut stone) is used the angles of the faces are cut to minimize shear forces. Where random masonry (uncut and unprepared stones)

414-415: A result, masonry arch bridges are designed to be constantly under compression, so far as is possible. Each arch is constructed over a temporary falsework frame, known as a centring . In the first compression arch bridges, a keystone in the middle of the bridge bore the weight of the rest of the bridge. The more weight that was put onto the bridge, the stronger its structure became. Masonry arch bridges use

483-430: A three-hinged bridge has hinged in all three locations. Most modern arch bridges are made from reinforced concrete . This type of bridge is suitable where a temporary centring may be erected to support the forms, reinforcing steel, and uncured concrete. When the concrete is sufficiently set the forms and falseworks are then removed. It is also possible to construct a reinforced concrete arch from precast concrete , where

552-456: Is 295 feet (90 m) above the canyon floor. The bridge was eventually unable to keep up with the growing traffic demands of US 97 (US 97), and was replaced by the wider Rex T. Barber Veterans Memorial Bridge in 2000. The old bridge is open to pedestrians. This article about a bridge in Oregon is a stub . You can help Misplaced Pages by expanding it . Arch bridge Possibly

621-521: Is 4,152 km (1,603 sq mi), of which 3,446 km (1,331 sq mi) are in Romania. If one includes the lagoons of Razim-Sinoe (1,015 km (392 sq mi) of which 865 km (334 sq mi) water surface), which are located south of the delta proper, but are related to it geologically and ecologically (their combined territory is part of the World Heritage Site),

690-428: Is a masonry, or stone, bridge where each successively higher course (layer) cantilevers slightly more than the previous course. The steps of the masonry may be trimmed to make the arch have a rounded shape. The corbel arch does not produce thrust, or outward pressure at the bottom of the arch, and is not considered a true arch . It is more stable than a true arch because it does not have this thrust. The disadvantage

759-471: Is also an important source of hydropower and drinking water . The Danube river basin is home to such fish species as pike , zander , huchen , Wels catfish , burbot and tench . It is also home to numerous diverse carp and sturgeon , as well as salmon and trout . A few species of euryhaline fish, such as European seabass , mullet , and eel , inhabit the Danube Delta and the lower portion of

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828-612: Is divided into three main parts, separated by "gates" where the river is forced to cut through mountainous sections: Mean annual discharge on the hydrological stations (period from 2000 to 2023); 1 - Reni , Isaccea ; 2 - Silistra ; 3 - Pristol ; 4 - Batina , Bezdan ; 5 - Nagymaros , Szob ; 6 - Bratislava , Wolfsthal ; 7 - Untergriesbach Multiannual average, minimum and maximum discharge (water period from 1876 to 2010) Simulated water and suspended sediment results from climate-driven decadal study (with STD through specific decade): P – Simulated average precipitation in

897-637: Is estimated that the Danube upper course will one day disappear entirely in favor of the Rhine, an event called stream capturing . The hydrological parameters of Danube are regularly monitored in Croatia at Batina , Dalj , Vukovar and Ilok . The Danube basin was the site of some of the earliest human cultures. The Danubian Neolithic cultures include the Linear Pottery cultures of the mid-Danube basin. Many sites of

966-432: Is that this type of arch is not suitable for large spans. In some locations it is necessary to span a wide gap at a relatively high elevation, such as when a canal or water supply must span a valley. Rather than building extremely large arches, or very tall supporting columns (difficult using stone), a series of arched structures are built one atop another, with wider structures at the base. Roman civil engineers developed

1035-653: Is to implement the Danube River Protection Convention by promoting and coordinating sustainable and equitable water management, including conservation, improvement, and rational use of waters and the implementation of the EU Water Framework Directive and the Danube Strategy . The Danube Commission is concerned with the maintenance and improvement of the river's navigation conditions. It was established in 1948 by seven countries bordering

1104-402: Is used they are mortared together and the mortar is allowed to set before the falsework is removed. Traditional masonry arches are generally durable, and somewhat resistant to settlement or undermining. However, relative to modern alternatives, such bridges are very heavy, requiring extensive foundations . They are also expensive to build wherever labor costs are high. The corbel arch bridge

1173-672: The Argonautica by Apollonius Rhodos (Argon. IV. 282). At the end of the Okeanos Potamos , is the holy island of Alba (Leuke, Pytho Nisi, Isle of Snakes ), sacred to the Pelasgian (and later, Greek) Apollo, greeting the sun rising in the east. Hecateus Abderitas refers to Apollo's island from the region of the Hyperboreans, in the Okeanos. It was on Leuke, in one version of his legend, that

1242-564: The Black Sea via the Danube Delta in Romania and Ukraine . Once a long-standing frontier of the Roman Empire , the river passes through or touches the borders of 10 countries. Its drainage basin extends into nine more (ten if Kosovo is included). In addition to the bordering countries (see above), the drainage basin includes parts of nine more countries: Bosnia and Herzegovina (4.6% of

1311-559: The Bystroye Canal . In 2022, there was a major heat wave in Europe. As a result, there was less water flowing in the rivers. As the water level decreased, a number of ship wrecks from World War II emerged in the Danube River. Many of the ships were from Nazi Germany 's Black Sea Fleet and had been scuttled to stop them from falling into enemy hands. The International Commission for

1380-682: The Danubian Limes was the northeastern border of the Empire, with occasional interruptions such as the fall of the Danubian Limes in 259. The crossing of the Danube into Dacia was achieved by the Imperium Romanum , first in two battles in 102 and then in 106 after the construction of a bridge in 101 near the garrison town of Drobeta at the Iron Gate. This victory over Dacia under Decebalus enabled

1449-620: The PIE * isro- , * sreu 'to flow'. In the Middle Ages, the Greek Tiras was borrowed into Italian as Tyrlo and into Turkic languages as Tyrla ; the latter was further borrowed into Romanian as a regionalism ( Turlă ). The Thraco- Phrygian name was Matoas , "the bringer of luck". The Middle Mongolian name for the Danube was transliterated as Tho-na in 1829 by Jean-Pierre Abel-Rémusat . The modern languages spoken in

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1518-460: The Romans were – as with the vault and the dome – the first to fully realize the potential of arches for bridge construction. A list of Roman bridges compiled by the engineer Colin O'Connor features 330 Roman stone bridges for traffic, 34 Roman timber bridges and 54 Roman aqueduct bridges , a substantial part still standing and even used to carry vehicles. A more complete survey by

1587-743: The 21st century, it connects ten European countries, running through their territories or marking a border. Originating in Germany , the Danube flows southeast for 2,850 km (1,770 mi), passing through or bordering Austria , Slovakia , Hungary , Croatia , Serbia , Romania , Bulgaria , Moldova , and Ukraine . Among the many cities on the river are four national capitals: Vienna , Bratislava , Budapest , and Belgrade . Its drainage basin amounts to 817,000 km (315,000 sq mi) and extends into nine more countries. The Danube's longest headstream Breg rises in Furtwangen im Schwarzwald , while

1656-752: The Danube basin all use names derived from the Latin name Danubius : Danube is an Old European river name derived from the Celtic ' danu ' or ' don ' (both Celtic gods), which itself derived from the Proto-Indo-European * deh₂nu . Other European river names from the same root include the Dunaj, Dzvina/ Daugava , Don , Donets , Dnieper , Dniestr , Dysna and Tana/Deatnu . In Rigvedic Sanskrit , danu (दनु) means "fluid, dewdrop" and danuja (दनु-ज) means "born from danu " or "born from dew-drops". In Avestan ,

1725-431: The Danube basin; T – Simulated average temperature in the Danube basin; Q – Simulated average discharge in the Danube River at delta; S – Simulated sediment load in the Danube River at delta ; Historical average flow to the present day; Measured and reconstructed average water flows from 1742. The reconstructed and observed streamflow (Q – m /s) at Ceatal Izmail for the 1742 to 2022: The land drained by

1794-1035: The Danube extends into many other countries. Many Danubian tributaries are important rivers in their own right, navigable by barges and other shallow-draught boats. From its source to its outlet into the Black Sea, its main tributaries are (as they enter): 18. Tisza (entering near Titel ) 19. Sava (entering at Belgrade ) 20. Timiș (river) (entering at Pančevo ) 21. Great Morava (entering near Smederevo ) 22. Mlava (entering near Kostolac ) 23. Karaš (entering near Banatska Palanka ) 24. Jiu (entering at Bechet ) 25. Iskar (entering near Gigen ) 26. Olt (entering at Turnu Măgurele ) 27. Osam (entering near Nikopol, Bulgaria ) 28. Yantra (entering near Svishtov ) 29. Argeș (entering at Oltenița ) 30. Ialomița 31. Siret (entering near Galați ) 32. Prut (entering near Galați ) The Danube flows through many cities, including four national capitals (shown below in bold), more than any other river in

1863-627: The Danube was variously known as Danubius , Danuvius , Ister or Hister . The Latin name is masculine, as are all its Slavic names, except Slovene (the name of the Rhine is also masculine in Latin, most of the Slavic languages, as well as in German). The German Donau ( Early Modern German Donaw , Tonaw , Middle High German Tuonowe ) is feminine, as it has been re-interpreted as containing

1932-591: The Danube's, today subsurface rivers carry much water from the Danube to the Rhine. On many days in the summer, when the Danube carries little water, it completely oozes away noisily into these underground channels at two locations in the Swabian Alb, which are referred to as the Donauversickerung ( Danube Sink ). Most of this water resurfaces only 12 km (7.5 mi) south at the Aachtopf , Germany's wellspring with

2001-512: The Danube. Today the Commission include riparian and non-riparian states. Although the headwaters of the Danube are relatively small today, geologically, the Danube is much older than the Rhine , with which its catchment area competes in today's southern Germany. This has a few interesting geological complications. Since the Rhine is the only river rising in the Alps mountains which flows north towards

2070-734: The Greeks borrowed the Istros form from the native Thracians. He proposes that the Romanian name is a loanword from a Turkic language ( Cuman or Pecheneg ). Classified as an international waterway , it originates in the town of Donaueschingen , in the Black Forest of Germany , at the confluence of the rivers Brigach and Breg . The Danube then flows southeast for about 2,730 km (1,700 mi), passing through four capital cities ( Vienna , Bratislava , Budapest , and Belgrade ) before emptying into

2139-517: The Italian scholar Vittorio Galliazzo found 931 Roman bridges, mostly of stone, in as many as 26 countries (including former Yugoslavia ). Roman arch bridges were usually semicircular , although a number were segmental arch bridges (such as Alconétar Bridge ), a bridge which has a curved arch that is less than a semicircle. The advantages of the segmental arch bridge were that it allowed great amounts of flood water to pass under it, which would prevent

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2208-702: The North Sea, an invisible line beginning at Piz Lunghin divides large parts of southern Germany, which is sometimes referred to as the European Watershed . Before the last ice age in the Pleistocene , the Rhine started at the southwestern tip of the Black Forest, while the waters from the Alps that today feed the Rhine were carried east by the so-called Urdonau (original Danube). Parts of this ancient river's bed, which

2277-590: The Protection of the Danube River (ICPDR) is an organization that consists of 14 member states (Germany, Austria, the Czech Republic, Slovakia, Slovenia, Hungary, Croatia, Bosnia and Herzegovina, Serbia, Bulgaria, Romania, Moldova, Montenegro, and Ukraine) and the European Union . The commission, established in 1998, deals with the whole Danube river basin, which includes tributaries and groundwater resources. Its goal

2346-626: The Province of Dacia to be created, but in 271 it was abandoned by emperor Aurelian . Avars used the river as their southeastern border in the 6th century. Part of the rivers Danubius or Istros was also known as (together with the Black Sea) the Okeanos in ancient times, being called the Okeanos Potamos (Okeanos River). The lower Danube was also called the Keras Okeanoio (Gulf or Horn of Okeanos) in

2415-680: The Serbian and the Romanian stretches of the Danube. However, the transgressions may not be considered acts of piracy, as defined according to the United Nations Convention on the Law of the Sea , but rather instances of "river robbery". On the other hand, media reports say the crews on transport ships often steal and sell their own cargo and then blame the plundering on "pirates", and the alleged attacks are not piracy but small-time contraband theft along

2484-436: The abutments of an arch bridge. The deck is suspended from the arch. The arch is in compression, in contrast to a suspension bridge where the catenary is in tension. A tied-arch bridge can also be a through arch bridge. An arch bridge with hinges incorporated to allow movement between structural elements. A single-hinged bridge has a hinge at the crown of the arch , a two-hinged bridge has hinges at both springing points and

2553-761: The acclaimed Florentine segmental arch bridge Ponte Vecchio (1345) combined sound engineering (span-to-rise ratio of over 5.3 to 1) with aesthetical appeal. The three elegant arches of the Renaissance Ponte Santa Trinita (1569) constitute the oldest elliptic arch bridge worldwide. Such low rising structures required massive abutments , which at the Venetian Rialto bridge and the Fleischbrücke in Nuremberg (span-to-rise ratio 6.4:1) were founded on thousands of wooden piles, partly rammed obliquely into

2622-416: The arch and the deck is known as the spandrel . If the spandrel is solid, usually the case in a masonry or stone arch bridge, the bridge is called a closed-spandrel deck arch bridge . If the deck is supported by a number of vertical columns rising from the arch, the bridge is known as an open-spandrel deck arch bridge . The Alexander Hamilton Bridge is an example of an open-spandrel arch bridge. Finally, if

2691-400: The arch is built in two halves which are then leaned against each other. Many modern bridges, made of steel or reinforced concrete, often bear some of their load by tension within their structure. This reduces or eliminates the horizontal thrust against the abutments and allows their construction on weaker ground. Structurally and analytically they are not true arches but rather a beam with

2760-422: The arch supports the deck only at the top of the arch, the bridge is called a cathedral arch bridge . This type of bridge has an arch whose base is at or below the deck, but whose top rises above it, so the deck passes through the arch. The central part of the deck is supported by the arch via suspension cables or tie bars, as with a tied-arch bridge . The ends of the bridge may be supported from below, as with

2829-603: The basin area), the Czech Republic (2.9%), Slovenia (2.0%), Montenegro (0.9%), Switzerland (0.2%), Italy (<0.15%), Poland (<0.1%), North Macedonia (<0.1%) and Albania (<0.1%). The total drainage basin is 801,463 km (309,447 sq mi) in area, and is home to 83 million people. The highest point of the drainage basin is the summit of Piz Bernina at the Italy–Switzerland border , at 4,049 m (13,284 ft). The Danube River Basin

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2898-615: 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 m-high (130 ft) 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 m-long (2,590 ft) long Puente Romano at Mérida . The late Roman Karamagara Bridge in Cappadocia may represent

2967-447: 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 ( voussoirs ) of the same in size and shape. The Romans built both single spans and lengthy multiple arch aqueducts , such as the Pont du Gard and Segovia Aqueduct . Their bridges featured from an early time onwards flood openings in

3036-414: The design and constructed highly refined structures using only simple materials, equipment, and mathematics. This type is still used in canal viaducts and roadways as it has a pleasing shape, particularly when spanning water, as the reflections of the arches form a visual impression of circles or ellipses. This type of bridge comprises an arch where the deck is completely above the arch. The area between

3105-536: The distance to the Black Sea by 400 km (250 mi); the Rhine–Main–Danube Canal is about 171 km (106 mi), finished in 1992, linking the North Sea to the Black Sea. A Danube-Aegean canal has been proposed. Danube River cruise for sightseeing is popular, especially between Passau , Germany, to Budapest , Hungary. In 2010–12, shipping companies, especially from Ukraine, claimed that their vessels suffered from "regular pirate attacks " on

3174-550: The earliest surviving bridge featuring a pointed arch. In medieval Europe, bridge builders improved on the Roman structures by using narrower piers , thinner arch barrels and higher span-to-rise ratios on bridges. Gothic pointed arches were also introduced, reducing lateral thrust, and spans increased as with the eccentric Puente del Diablo (1282). The 14th century in particular saw bridge building reaching new heights. Span lengths of 40 m (130 ft), previously unheard of in

3243-721: The gorge) by the Iron Gate II Hydroelectric Power Station . On 13 April 2006, a record peak discharge at Iron Gate Dam reached 15,400 m /s (540,000 cu ft/s). There are three artificial waterways built on the Danube: the Danube-Tisa-Danube Canal (DTD) in the Banat and Bačka regions ( Vojvodina , northern province of Serbia); the 64 km (40 mi) Danube-Black Sea Canal , between Cernavodă and Constanța (Romania) finished in 1984, shortens

3312-492: The grounds to counteract more effectively the lateral thrust. In China, the oldest existing arch bridge is the Zhaozhou Bridge of 605 AD, which combined a very low span-to-rise ratio of 5.2:1, with the use of spandrel arches (buttressed with iron brackets). The Zhaozhou Bridge, with a length of 167 feet (51 m) and span of 123 feet (37 m), is the world's first wholly stone open-spandrel segmental arch bridge, allowing

3381-521: The hero Achilles was buried (to this day, one of the mouths of the Danube is called Chilia). Old Romanian folk songs recount a white monastery on a white island with nine priests. Between the late 14th and late 19th centuries, the Ottoman Empire competed first with the Kingdom of Serbia , Second Bulgarian Empire , Kingdom of Hungary , Principality of Wallachia , Principality of Moldavia and later with

3450-423: The highest flow, an average of 8,500 L/s (300 cu ft/s), north of Lake Constance —thus feeding the Rhine. The European Water Divide applies only for those waters that pass beyond this point, and only during the days of the year when the Danube carries enough water to survive the sinkholes in the Donauversickerung. Since such large volumes of underground water erode much of the surrounding limestone, it

3519-443: The history of masonry arch construction, were now reached in places as diverse as Spain ( Puente de San Martín ), Italy ( Castelvecchio Bridge ) and France ( Devil's bridge and Pont Grand ) and with arch types as different as semi-circular, pointed and segmental arches. The bridge at Trezzo sull'Adda , destroyed in the 15th century, even featured a span length of 72 m (236 ft), not matched until 1796. Constructions such as

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3588-520: The northern barbarian Thracian and Illyrian tribes by advancing from Macedonia as far as the Danube in 336 BCE. Under the Romans, the Danube formed the border of the Empire with the tribes to the north almost from its source to its mouth. At the same time, it was a route for the transport of troops and the supply of settlements downstream. From 37 CE to the reign of the Emperor Valentinian I (364–375)

3657-578: The oldest existing arch bridge is the Mycenaean Arkadiko Bridge in Greece from about 1300 BC. The stone corbel arch bridge is still used by the local populace. The well-preserved Hellenistic Eleutherna Bridge has a triangular corbel arch. The 4th century BC Rhodes Footbridge rests on an early voussoir arch. Although true arches were already known by the Etruscans and ancient Greeks ,

3726-821: 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 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 m-long (1,080 ft) Limyra Bridge in southwestern Turkey features 26 segmental arches with an average span-to-rise ratio of 5.3:1, giving

3795-403: The river carries its name from its source confluence in the palace park in Donaueschingen onwards. Since ancient times, the Danube has been a traditional trade route in Europe. Today, 2,415 km (1,501 mi) of its total length are navigable. The Danube is linked to the North Sea via the Rhine–Main–Danube Canal , connecting the Danube at Kelheim with the Main at Bamberg . The river

3864-465: The river has been part of a trans-European waterway from Rotterdam on the North Sea to Sulina on the Black Sea, a distance of 3,500 km (2,200 mi). In 1994 the Danube was declared one of ten Pan-European transport corridors , routes in Central and Eastern Europe that required major investment over the following ten to fifteen years. The amount of goods transported on the Danube increased to about 100 million tons in 1987. In 1999, transport on

3933-481: The river was made difficult by the NATO bombing of three bridges in Serbia during the Kosovo War . Clearance of the resulting debris was completed in 2002, and a temporary pontoon bridge that hampered navigation was removed in 2005. At the Iron Gate , the Danube flows through a gorge that forms part of the boundary between Serbia and Romania; it contains the Iron Gate I Hydroelectric Power Station dam, followed at about 60 km (37 mi) downstream (outside

4002-426: The river. The Danube Delta ( Romanian : Delta Dunării pronounced [ˈdelta ˈdunərij] ; Ukrainian : Дельта Дунаю , romanized :  Del'ta Dunayu ) is the largest river delta in the European Union . The greater part of the Danube Delta lies in Romania (Tulcea county), while its northern part, on the left bank of the Chilia arm, is situated in Ukraine (Odesa Oblast). The approximate surface

4071-486: The river. Today the river carries its name from its source confluence in Donaueschingen , Germany , to its discharge into the Black Sea via the Danube Delta in Romania and Ukraine . The river was known to the ancient Greeks as the Istros ( Ἴστρος ) from a root possibly also encountered in the ancient name of the Dniester ( Danaster in Latin, Tiras in Greek) and akin to Iranic turos 'swift' and Sanskrit iṣiras ( इषिरस् ) 'swift', from

4140-443: The river. Members include representatives from Austria, Bulgaria, Croatia, Germany, Hungary, Moldova, Slovakia, Romania, Russia, Ukraine, and Serbia; it meets regularly twice a year. It also convenes groups of experts to consider items provided for in the commission's working plans. The commission dates to the Paris Conferences of 1856 and 1921, which established for the first time an international regime to safeguard free navigation on

4209-491: The same word means "river". The Finnish word for Danube is Tonava , which is most likely derived from the name of the river in German , Donau . Its Sámi name Deatnu means "Great River". It is possible that dānu in Scythian as in Avestan was a generic word for "river": Dnieper and Dniestr , from Danapris and Danastius , are presumed to continue Scythian * dānu apara "far river" and * dānu nazdya- "near river", respectively. In Latin,

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4278-402: The shape of an arch. See truss arch bridge for more on this type. A modern evolution of the arch bridge is the long-span through arch bridge . This has been made possible by the use of light materials that are strong in tension such as steel and prestressed concrete. "The Romans were the first builders in Europe, perhaps the first in the world, fully to appreciate the advantages of the arch,

4347-427: The sixth-to-third millennium BCE Vinča culture (Vinča, Serbia), are sited along the Danube. The third millennium BCE Vučedol culture (from the Vučedol site near Vukovar , Croatia ) is famous for its ceramics. Darius the Great , king of Persia , crossed the river in the late 6th century BCE to invade European Scythia and to subdue the Scythians . Alexander the Great defeated the Triballian king Syrmus and

4416-415: The suffix -ouwe "wetland". Romanian differs from other surrounding languages in designating the river with a feminine term, Dunărea ( IPA: [ˈdunəre̯a] ). This form was not inherited from Latin, although Romanian is a Romance language. To explain the loss of the Latin name, scholars who suppose that Romanian developed near the large river propose that the Romanian name descends from

4485-490: The total area of the Danube Delta reaches 5,165 km (1,994 sq mi). The Danube Delta is also the best-preserved river delta in Europe, a UNESCO World Heritage Site (since 1991) and a Ramsar Site . Its lakes and marshes support 45 freshwater fish species. Its wetlands support vast flocks of migratory birds of over 300 species, including the endangered pygmy cormorant ( Phalacrocorax pygmaeus ). These are threatened by rival canalization and drainage schemes such as

4554-404: The vault and the dome." Danube The Danube ( / ˈ d æ n . j uː b / DAN -yoob ; see also other names ) is the second-longest river in Europe , after the Volga in Russia . It flows through Central and Southeastern Europe , from the Black Forest south into the Black Sea . A large and historically important river, it was once a frontier of the Roman Empire . In

4623-431: The world. Ordered from the source to the mouth they are: The Danube is navigable by ocean ships from the Black Sea to Brăila in Romania (the maritime river sector), and further on by river ships to Kelheim , Bavaria , Germany; smaller craft can navigate further upstream to Ulm , Württemberg , Germany. About 60 of its tributaries are also navigable. Since the completion of the German Rhine–Main–Danube Canal in 1992,

4692-402: Was Jean-Rodolphe Perronet , who used much narrower piers, revised calculation methods and exceptionally low span-to-rise ratios. Different materials, such as cast iron , steel and concrete have been increasingly used in the construction of arch bridges. Stone, brick and other such materials are strong in compression and somewhat so in shear , but cannot resist much force in tension . As

4761-414: Was much larger than today's Danube, can still be seen in (now waterless) canyons in today's landscape of the Swabian Alb . After the Upper Rhine valley had been eroded, most waters from the Alps changed their direction and began feeding the Rhine. Today's upper Danube is thus an underfit stream . Since the Swabian Alb is largely shaped of porous limestone , and since the Rhine's level is much lower than

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