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21-515: One of the first hinged arch bridges in the world, and the first (and only preserved) cast iron bridge in Slovenia, it was praised as a technical achievement at its construction in 1867, as well as for its elegance, modernity, and cost-effectiveness. The bridge's modular construction has made it relatively easy to relocate, and it has been moved twice. By virtue of its location on the route used to transport decedents from Ljubljana's main hospital to

42-530: A bolt at the highest point of the arch. The elements are joined with screws instead of wedges, and reinforcing bars and hollow elements were used instead of full pylons, which enable the bridge to be much lighter while remaining stable. The design represents several major technical advancements over the first generation of cast-iron bridges, such as the 1781 Iron Bridge across the Severn in England. The bridge

63-541: A hinge involves thinning of the concrete structure while adding more reinforcement locally. Early arch bridges were fixed arches. The two-hinged bridge was developed by the engineers Couche and Salle in 1858 for a wrought iron bridge carrying the Paris-Creil railway line across the Canal Saint-Denis . They had attempted to introduce a third hinge at the crown but were unsuccessful because the thickness of

84-402: A hinge is essentially a "cut in the structure" that can withstand compressive forces. In a steel arch the hinge allows free rotation, somewhat resembling a common hinge . The most common hinged arch bridge varieties are the two-hinged bridge with hinges at the springing points and the three-hinged bridge with an additional hinge at the crown of the arch; though single-hinged versions exist with

105-417: A hinge only at the crown of the arch. Hinges at the springing point prevent bending moments from being transferred to the bridge abutments. A triple-hinged bridge is statically determinate , while the other versions are not. A fixed arch bridge, that is one without hinges, exerts a bending moment at the abutments and stresses caused by change of temperature or shrinkage of concrete have to be taken up by

126-723: A structure is statically indeterminate when the equilibrium equations – force and moment equilibrium conditions – are insufficient for determining the internal forces and reactions on that structure. Based on Newton's laws of motion , the equilibrium equations available for a two-dimensional body are: In the beam construction on the right, the four unknown reactions are V A , V B , V C , and H A . The equilibrium equations are: Since there are four unknown forces (or variables ) ( V A , V B , V C , and H A ) but only three equilibrium equations, this system of simultaneous equations does not have

147-429: A structure. In order to distinguish between this and the situation when a system under equilibrium is perturbed and becomes unstable, it is preferable to use the phrase partly constrained here. In this case, the two unknowns V A and V C can be determined by resolving the vertical force equation and the moment equation simultaneously. The solution yields the same results as previously obtained. However, it

168-422: A unique solution. The structure is therefore classified as statically indeterminate . To solve statically indeterminate systems (determine the various moment and force reactions within it), one considers the material properties and compatibility in deformations . If the support at B is removed, the reaction V B cannot occur, and the system becomes statically determinate (or isostatic ). Note that

189-755: Is a particularly large example of a three-hinged arch bridge. At 540 feet (160 m) in length it was the longest in America when built. The 1888 Hennepin Avenue Bridge in Minneapolis was unusual in that it was both a two- and three-hinged bridge. The bridge was split longitudinally with the two halves being built by different companies. The north arch ribs are three-hinged, while the south arch ribs are two-hinged. Three-hinged arch bridges remain popular in modern civil engineering. Statically determinate In statics and structural mechanics ,

210-450: Is not possible to satisfy the horizontal force equation unless F h = 0 . Descriptively, a statically determinate structure can be defined as a structure where, if it is possible to find internal actions in equilibrium with external loads, those internal actions are unique. The structure has no possible states of self-stress, i.e. internal forces in equilibrium with zero external loads are not possible. Statical indeterminacy, however,

231-559: Is the existence of a non-trivial (non-zero) solution to the homogeneous system of equilibrium equations. It indicates the possibility of self-stress (stress in the absence of an external load) that may be induced by mechanical or thermal action. Mathematically, this requires a stiffness matrix to have full rank. A statically indeterminate structure can only be analyzed by including further information like material properties and deflections. Numerically, this can be achieved by using matrix structural analyses, finite element method (FEM) or

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252-469: The Gruden Embankment ( Grudnovo nabrežje ). It reopened in 2011 as a footbridge for pedestrians and cyclists only. 46°2′39.68″N 14°30′20.70″E  /  46.0443556°N 14.5057500°E  / 46.0443556; 14.5057500 Hinged arch bridge A hinged arch bridge is one with hinges incorporated into its structure to allow movement. In structural engineering,

273-634: The Second World War . Post-war, the advances in calculation methods allowed broad use of statically indeterminate schemes. In the end of the 20th century three-hinged arches made a comeback associated with the uses of engineered wood (" glulam ") in bridge construction: the glulam construction have to be pre-fabricated, using three-hinged design naturally divides the arch into two halves that are easier to transport. While in steel arches hinges typically allow free rotation of connected parts, in reinforced concrete bridges typical implementation of

294-400: The abutments may cause a change in the thrust load exerted by the arch on the abutments. The addition of a third hinge at the crown, which allows rotation of the arch members, means that the thrust and shear forces exerted on the abutments are not affected by small movements in either abutment. Three-hinged arch bridges are, therefore, used when there is the possibility of unequal settlement of

315-451: The abutments. Single-hinged arch bridges, with a hinge only at the crown, were also built though in relatively small numbers compared to the other types. A three hinged bridge is isostatic, that is it is statically determinate ; a two-hinged bridge is statically indeterminate in one degree of freedom , while a fixed arch bridge is indeterminate in three degrees of freedom. The statically determinate three-hinged arches were popular until

336-661: The arch was insufficient. The first three-hinged bridge was the Unterspree Bridge in Berlin ( Johann Wilhelm Schwedler , 1863), built two years after the pioneering theoretical work by Claus Koepcke  [ de ] . Hradecky Bridge (1866) is probably the oldest three-hinged bridge still used. Hinged bridges were popular with railway companies, who often had the need to construct large bridges. The Arch Bridge at Bellows Falls in New England, built in 1905,

357-405: The arch. A two-hinged arch has a hinge at the base of each arch (the springing point), while a three-hinged arch has a third hinge at the crown of the arch . The advantage of the fixed arches is in their lower construction and maintenance costs. In a two-hinged arch bridge no bending moments are transferred to the abutments, due to the presence of the hinge. A change in the relative position of

378-706: The city mortuary (between 1931 and 2010), it gained the somber nickname " Bridge of the Dead" ( Mrtvaški most ), which remains in colloquial use. The bridge was manufactured according to the plans of engineer Johann Hermann from Vienna at the Auersperg iron foundry in Dvor near Žužemberk , and was installed as the first cast iron bridge in Ljubljana in 1867, replacing the wooden Cobblers' Bridge . It has three articulated arches , each of them made of two sections joined by

399-510: The original gas lamps at its corners with Secession -style concrete spires housing electric street-lamps. In 2004, the bridge (which had never been intended for motor vehicles) was determined to be unsafe and was closed to all traffic, with a temporary footbridge built alongside it in 2009. In 2010, the bridge was dismantled, renovated, and transferred to its current site, connecting the Krakovo Embankment ( Krakovski nasip ) and

420-403: The system is completely constrained here. The system becomes an exact constraint kinematic coupling . The solution to the problem is: If, in addition, the support at A is changed to a roller support, the number of reactions are reduced to three (without H A ), but the beam can now be moved horizontally; the system becomes unstable or partly constrained —a mechanism rather than

441-585: Was officially named after 1820-1846 Ljubljana mayor Johann Nepomuk Hradeczky , but was (at its original location) commonly known as the Cobblers' Bridge . In 1931, the architect Jože Plečnik designed the current iteration of the Cobblers' Bridge , moving the Hradecky Bridge further down the Ljubljanica to a site near the former Ljubljana mortuary on Zaloška Street, at which point he also replaced

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