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Ravenna Bridge
The Ravenna Bridge is a high and 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 . The origin of the name most likely comes from the French ''ravin'' for gorge. History and construction 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 and an axle load of . Heavier locomotives and faster speeds led to the construction in 1926–27 of the current structure, a mortared stone viaduct with nine arches and an arch span of , 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 origina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Höllentalbahn (Black Forest)
The Höllentalbahn (literally, "Hell Valley Railway") is a railway line that partially runs through the Höllental valley in the Black Forest of Germany. The line connects Freiburg im Breisgau with Donaueschingen, a distance of . Over its entire course the line rises from an altitude of in Freiburg to in Hinterzarten. Part of the route has a 5.5% gradient, making the line one of the steepest in Germany. The section Freiburg-Neustadt is electrified since 18 June 1936. Because of this and the steady decrease of traffic between Neustadt and Donaueschingen the route did not represent an operational unit anymore. The last direct connection between Freiburg and Donaueschingen ended in 2003 with the Kleber-Express Freiburg-Munich being discontinued. The missing section was electrified until the end of 2019 in the course of the project “Breisgau-S-Bahn 2020”, in order to enable direct trains from Breisach via Freiburg, Neustand and Donaueschingen to Villingen. History The line, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cantilever Bridge
A cantilever bridge is a bridge built using structures that project horizontally into space, supported on only one end (called cantilevers). For small footbridges, the cantilevers may be simple beam (structure), beams; however, large cantilever bridges designed to handle road or rail traffic use trusses built from structural steel, or box girders built from prestressed concrete. The steel truss cantilever bridge was a major engineering breakthrough when first put into practice, as it can span distances of over , and can be more easily constructed at difficult crossings by virtue of using little or no falsework. Origins Civil engineer, Engineers in the 19th century understood that a bridge that was continuous across multiple supports would distribute the loads among them. This would result in lower stresses in the girder or truss and meant that longer spans could be built. Several 19th-century engineers patented continuous bridges with hinge points mid-span. The use of a hing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stone Bridges In Germany
In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is formed. Rocks form the Earth's outer solid layer, the crust, and most of its interior, except for the liquid outer core and pockets of magma in the asthenosphere. The study of rocks involves multiple subdisciplines of geology, including petrology and mineralogy. It may be limited to rocks found on Earth, or it may include planetary geology that studies the rocks of other celestial objects. Rocks are usually grouped into three main groups: igneous rocks, sedimentary rocks and metamorphic rocks. Igneous rocks are formed when magma cools in the Earth's crust, or lava cools on the ground surface or the seabed. Sedimentary rocks are formed by diagenesis and lithification of sediments, which in turn are formed by the weathering, transport, and deposition of existing ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Railway Bridges In Germany
Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a prepared flat surface, rail vehicles (rolling stock) are directionally guided by the tracks on which they run. Tracks usually consist of steel rails, installed on sleepers (ties) set in ballast, on which the rolling stock, usually fitted with metal wheels, moves. Other variations are also possible, such as "slab track", in which the rails are fastened to a concrete foundation resting on a prepared subsurface. Rolling stock in a rail transport system generally encounters lower frictional resistance than rubber-tyred road vehicles, so passenger and freight cars (carriages and wagons) can be coupled into longer trains. The operation is carried out by a railway company, providing transport between train stations or freight customer faciliti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allied Occupation Zones In Germany
Germany was already de facto occupied by the Allies from the real fall of Nazi Germany in World War II on 8 May 1945 to the establishment of the East Germany on 7 October 1949. The Allies (United States, United Kingdom, Soviet Union, and France) asserted joint authority and sovereignty at the 1945 Berlin Declaration. At first, defining Allied-occupied Germany as all territories of the former German Reich before Nazi annexing Austria; however later in the 1945 Potsdam Conference of Allies, the Potsdam Agreement decided the new German border as it stands today. Said border gave Poland and the Soviet Union all regions of Germany (eastern parts of Pomerania, Neumark, Posen-West Prussia, Free City of Danzig, East-Prussia & Silesia) east of the Oder–Neisse line and divided the remaining "Germany as a whole" into the four occupation zones for administrative purposes under the three Western Allies (the United States, the United Kingdom, and France) and the Soviet Union. Although the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abutment
An abutment is the substructure at the ends of a bridge span or dam supporting its superstructure. Single-span bridges have abutments at each end which provide vertical and lateral support for the span, as well as acting as retaining walls to resist lateral movement of the earthen fill of the bridge approach. Multi-span bridges require piers to support ends of spans unsupported by abutments. Dam abutments are generally the sides of a valley or gorge, but may be artificial in order to support arch dams such as Kurobe Dam in Japan. The civil engineering term may also refer to the structure supporting one side of an arch, or masonry used to resist the lateral forces of a vault.Pevsner, N. (1970) ''Cornwall''; 2nd ed. Harmondsworth: Penguin; p. 245 The impost or abacus of a column in classical architecture may also serve as an abutment to an arch. The word derives from the verb "abut", meaning to "touch by means of a mutual border". Use in engineering An abutment may be us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axle Load
An axle or axletree is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, bearings or bushings are provided at the mounting points where the axle is supported. In the latter case, a bearing or bushing sits inside a central hole in the wheel to allow the wheel or gear to rotate around the axle. Sometimes, especially on bicycles, the latter type axle is referred to as a ''spindle''. Terminology On cars and trucks, several senses of the word ''axle'' occur in casual usage, referring to the shaft itself, its housing, or simply any transverse pair of wheels. Strictly speaking, a shaft which rotates with the wheel, being either bolted or splined in fixed relation to it, is called an ''axle'' or ''axle shaft''. However, in looser usage, an entire assembly including the surrounding axle housing (typically a casting) is als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) because they are the most resistant minerals to weathering processes at the Earth's surface. Like uncemented sand, sandstone may be any color due to impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions. Rock formations that are primarily composed of sandstone usually allow the percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Quartz-bearing sandstone can be changed into quartzite through metamorphism, usually related to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grade (slope)
The grade (also called slope, incline, gradient, mainfall, pitch or rise) of a physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal. It is a special case of the slope, where zero indicates horizontality. A larger number indicates higher or steeper degree of "tilt". Often slope is calculated as a ratio of "rise" to "run", or as a fraction ("rise over run") in which ''run'' is the horizontal distance (not the distance along the slope) and ''rise'' is the vertical distance. Slopes of existing physical features such as canyons and hillsides, stream and river banks and beds are often described as grades, but typically grades are used for human-made surfaces such as roads, landscape grading, roof pitches, railroads, aqueducts, and pedestrian or bicycle routes. The grade may refer to the longitudinal slope or the perpendicular cross slope. Nomenclature There are several ways to express slope: # as an ''angle'' of inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breitnau
Breitnau is a municipality in the district of Breisgau-Hochschwarzwald in Baden-Württemberg in southern Germany, about 30 kilometres from the city of Freiburg im Breisgau. It is located within the High Black Forest. Geography The municipality of Breitnau is very spread out, with many, scattered, farmsteads, some of the very large, most of which have farmhouses with half-hipped roofs, typical of the Black Forest. The actual village centre is comparatively small, but has grown in recent years. The highest mountain is the Weißtannenhöhe ("Silver Fir Height") which is 1,190 metres high. North of the village rises the Roßberg (1,125 m) and about 1 km to the northwest of the village on the same ridge is the Hohwart (1,123 m). Municipal subdivisions The municipality of Breitnau incorporates the villages of Hinterdorf, Steig (since 1935 part of Breitnau) and Vorderdorf, the Zinken Beim Löwen, Bisten (partly also in Hinterzarten), Bruckbach, Eckbach, Einsiedel, Fahrenberg, Fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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