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61-653: The Margaret McDermott Bridge is a conventional concrete pier-and-beam freeway bridge with cable-stayed bike lines over the Trinity River in Dallas , Texas. It replaced the late-1950s to early-1960s Interstate 30 (I-30) bridge, which reached its end of life. It was partially designed by Santiago Calatrava , and is part of the Trinity River Project and the Horseshoe Project . It

122-427: A 2 in (50.8 mm) diameter rope. The mnemonic "never saddle a dead horse" means that when installing clips, the saddle portion of the assembly is placed on the load-bearing or "live" side, not on the non-load-bearing or "dead" side of the cable. This is to protect the live or stress-bearing end of the rope against crushing and abuse. The flat bearing seat and extended prongs of the body are designed to protect

183-460: A 2-span or 3-span cable-stayed bridge, the loads from the main spans are normally anchored back near the end abutments by stays in the end spans. For more spans, this is not the case and the bridge structure is less stiff overall. This can create difficulties in both the design of the deck and the pylons. Examples of multiple-span structures in which this is the case include Ting Kau Bridge , where additional 'cross-bracing' stays are used to stabilise

244-460: A carbon content of 0.4 to 0.95%. The very high strength of the rope wires enables wire ropes to support large tensile forces and to run over sheaves with relatively small diameters. In the so-called cross lay strands, the wires of the different layers cross each other. In the mostly used parallel lay strands, the lay length of all the wire layers is equal and the wires of any two superimposed layers are parallel, resulting in linear contact. The wire of

305-471: A centre with at least one layer of wires being laid in the opposite direction to that of the outer layer. Spiral ropes can be dimensioned in such a way that they are non-rotating which means that under tension the rope torque is nearly zero. The open spiral rope consists only of round wires. The half-locked coil rope and the full-locked coil rope always have a centre made of round wires. The locked coil ropes have one or more outer layers of profile wires. They have

366-483: A conventional concrete pier-and-beam concrete part which has a 1,125 feet (343 m) main span. The concrete part carries 10 main lanes of I-30 traffic with one reversible high-occupancy vehicle lane and four frontage road lanes. The decorative steel arches are both 350 feet (110 m) tall, and house paths for bicycle and pedestrian facilities. Cable-stayed bridge A cable-stayed bridge has one or more towers (or pylons ), from which cables support

427-670: A dispute between the City, TxDOT, and now the engineering firm responsible for the dangerous final product. So far, there are not reports that cables have struck vehicles. In January 2021, the Dallas Morning News reported that the bridge could be open to pedestrians to walk and bike over the Trinity River before the end of the year. The bridge officially opened to pedestrians and cyclists in June 2021. The bridge consists of

488-509: A lack of testing and using the wrong parts, and state transportation officials blamed Calatrava and the city of Dallas. Due to that, coupled with the need to add additional painting and lighting, the arched bridges opened to pedestrian and bicycle traffic in June of 2021. In April 2019, the Dallas City Council approved a repair expected to cost over $ 7 million and take over three years. The arched pedestrian bridge has resulted in

549-435: A reference rope length, of cross-section loss, as well as other failures so that the wire rope can be replaced before a dangerous situation occurs. Installations should be designed to facilitate the inspection of the wire ropes. Lifting installations for passenger transportation require that a combination of several methods should be used to prevent a car from plunging downwards. Elevators must have redundant bearing ropes and

610-419: A safety gear. Ropeways and mine hoistings must be permanently supervised by a responsible manager and the rope must be inspected by a magnetic method capable of detecting inner wire breaks. The end of a wire rope tends to fray readily, and cannot be easily connected to plant and equipment. There are different ways of securing the ends of wire ropes to prevent fraying. The common and useful type of end fitting for

671-418: A wire rope is to turn the end back to form a loop. The loose end is then fixed back on the wire rope. Termination efficiencies vary from about 70% for a Flemish eye alone; to nearly 90% for a Flemish eye and splice; to 100% for potted ends and swagings. When the wire rope is terminated with a loop, there is a risk that it will bend too tightly, especially when the loop is connected to a device that concentrates

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732-679: Is a cable-stayed bridge with a more substantial bridge deck that, being stiffer and stronger, allows the cables to be omitted close to the tower and for the towers to be lower in proportion to the span. The first extradosed bridges were the Ganter Bridge and Sunniberg Bridge in Switzerland. The first extradosed bridge in the United States, the Pearl Harbor Memorial Bridge was built to carry I-95 across

793-437: Is a fiber core, made up of synthetic material or natural fibers like sisal. Synthetic fibers are stronger and more uniform but cannot absorb much lubricant. Natural fibers can absorb up to 15% of their weight in lubricant and so protect the inner wires much better from corrosion than synthetic fibers do. Fiber cores are the most flexible and elastic, but have the downside of getting crushed easily. The second type, wire strand core,

854-469: Is a method of wire rope termination that refers to the installation technique. The purpose of swaging wire rope fittings is to connect two wire rope ends together, or to otherwise terminate one end of wire rope to something else. A mechanical or hydraulic swager is used to compress and deform the fitting, creating a permanent connection. Threaded studs, ferrules, sockets, and sleeves are examples of different swaged terminations. Swaging ropes with fibre cores

915-403: Is made up of one additional strand of wire, and is typically used for suspension. The third type is independent wire rope core (IWRC), which is the most durable in all types of environments. Most types of stranded ropes only have one strand layer over the core (fibre core or steel core). The lay direction of the strands in the rope can be right (symbol Z) or left (symbol S) and the lay direction of

976-402: Is not recommended. A wedge socket termination is useful when the fitting needs to be replaced frequently. For example, if the end of a wire rope is in a high-wear region, the rope may be periodically trimmed, requiring the termination hardware to be removed and reapplied. An example of this is on the ends of the drag ropes on a dragline . The end loop of the wire rope enters a tapered opening in

1037-507: Is optimal for spans longer than cantilever bridges and shorter than suspension bridges. This is the range within which cantilever bridges would rapidly grow heavier, and suspension bridge cabling would be more costly. Cable-stayed bridges were being designed and constructed by the late 16th century, and the form found wide use in the late 19th century. Early examples, including the Brooklyn Bridge , often combined features from both

1098-404: Is the main material used for wire ropes. Historically, wire rope evolved from wrought iron chains, which had a record of mechanical failure. While flaws in chain links or solid steel bars can lead to catastrophic failure , flaws in the wires making up a steel cable are less critical as the other wires easily take up the load. While friction between the individual wires and strands causes wear over

1159-725: The Lehigh Coal & Navigation Company (LC&N Co.) — as they had with the first blast furnaces in the Lehigh Valley — built a Wire Rope factory in Jim Thorpe, Pennsylvania , in 1848, which provided lift cables for the Ashley Planes project, then the back track planes of the Summit Hill & Mauch Chunk Railroad , improving its attractiveness as a premier tourism destination, and vastly improving

1220-652: The Margaret Hunt Hill Bridge began, and it opened on March 29, 2012. The Margaret McDermott Bridge was planned to replace the existing I-30 bridge over the Trinity River. It was originally scheduled to begin construction in 2011 and be completed by 2014. However, in late 2011 funding for the bridge was moved to come from within the Project Pegasus initiative, with construction contracts awarded in mid-2012. The new plan featured "toned-down" elements of its original arch design, although Calatrava

1281-608: The Penobscot Narrows Bridge , completed in 2006, and the Veterans' Glass City Skyway , completed in 2007. A self-anchored suspension bridge has some similarity in principle to the cable-stayed type in that tension forces that prevent the deck from dropping are converted into compression forces vertically in the tower and horizontally along the deck structure. It is also related to the suspension bridge in having arcuate main cables with suspender cables, although

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1342-580: The Ruhr Valley . With important patents, and dozens of working systems in Europe, Bleichert dominated the global industry, later licensing its designs and manufacturing techniques to Trenton Iron Works, New Jersey, USA which built systems across America. Adolf Bleichert & Co. went on to build hundreds of aerial tramways around the world: from Alaska to Argentina, Australia and Spitsbergen. The Bleichert company also built hundreds of aerial tramways for both

1403-486: The Theodor Heuss Bridge (1958). However, this involves substantial erection costs, and more modern structures tend to use many more cables to ensure greater economy. Cable-stayed bridges may appear to be similar to suspension bridges , but they are quite different in principle and construction. In suspension bridges, large main cables (normally two) hang between the towers and are anchored at each end to

1464-451: The live load of traffic crossing the bridge. The tension on the main cables is transferred to the ground at the anchorages and by downwards compression on the towers. In cable-stayed bridges, the towers are the primary load-bearing structures that transmit the bridge loads to the ground. A cantilever approach is often used to support the bridge deck near the towers, but lengths further from them are supported by cables running directly to

1525-507: The Donzère-Mondragon canal at Pierrelatte is one of the first of the modern type, but had little influence on later development. The steel-decked Strömsund Bridge designed by Franz Dischinger (1955) is, therefore, more often cited as the first modern cable-stayed bridge. Other key pioneers included Fabrizio de Miranda , Riccardo Morandi , and Fritz Leonhardt . Early bridges from this period used very few stay cables, as in

1586-613: The Imperial German Army and the Wehrmacht. In the latter part of the 19th century, wire rope systems were used as a means of transmitting mechanical power including for the new cable cars . Wire rope systems cost one-tenth as much and had lower friction losses than line shafts . Because of these advantages, wire rope systems were used to transmit power for a distance of a few miles or kilometers. Steel wires for wire ropes are normally made of non-alloy carbon steel with

1647-585: The Quinnipiac River in New Haven, Connecticut, opening in June 2012. A cradle system carries the strands within the stays from the bridge deck to bridge deck, as a continuous element, eliminating anchorages in the pylons. Each epoxy-coated steel strand is carried inside the cradle in a one-inch (2.54 cm) steel tube. Each strand acts independently, allowing for removal, inspection, and replacement of individual strands. The first two such bridges are

1708-591: The United States as surface deposits in the Anthracite Coal Region north and south dove deeper every year, and even the rich deposits in the Panther Creek Valley required LC&N Co. to drive their first shafts into lower slopes beginning Lansford and its Schuylkill County twin-town Coaldale . The German engineering firm of Adolf Bleichert & Co. was founded in 1874 and began to build bicable aerial tramways for mining in

1769-451: The advantage that their construction prevents the penetration of dirt and water to a greater extent and it also protects them from loss of lubricant. In addition, they have one further very important advantage as the ends of a broken outer wire cannot leave the rope if it has the proper dimensions. Stranded ropes are an assembly of several strands laid helically in one or more layers around a core. This core can be one of three types. The first

1830-409: The bridge deck. A distinctive feature are the cables or stays , which run directly from the tower to the deck, normally forming a fan-like pattern or a series of parallel lines. This is in contrast to the modern suspension bridge , where the cables supporting the deck are suspended vertically from the main cable, anchored at both ends of the bridge and running between the towers. The cable-stayed bridge

1891-547: The bridge, which also house the pedestrian and bicycle paths, are separate from the concrete part. In April 2014, footings for the arches were constructed, while steel fabrication took place at Tampa Steel Erecting Company's plant in Florida. The superstructure subcontractor to CRC Joint Venture, American Bridge, expected steel components to arrive on site in Dallas during the fall of 2014. The steel arches were completed in 2017, and

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1952-405: The cable-stayed and suspension designs. Cable-stayed designs fell from favor in the early 20th century as larger gaps were bridged using pure suspension designs, and shorter ones using various systems built of reinforced concrete . It returned to prominence in the later 20th century when the combination of new materials, larger construction machinery, and the need to replace older bridges all lowered

2013-562: The cable-stayed bridge are balanced so that the supporting towers do not tend to tilt or slide and so must only resist horizontal forces from the live loads. The following are key advantages of the cable-stayed form: There are four major classes of rigging on cable-stayed bridges: mono , harp , fan, and star . There are also seven main arrangements for support columns: single , double , portal , A-shaped , H-shaped , inverted Y and M-shaped . The last three are hybrid arrangements that combine two arrangements into one. Depending on

2074-525: The cockpit. Only aircraft cables have WSC (wire strand core). Also, aircraft cables are available in smaller diameters than wire rope. For example, aircraft cables are available in 1.2 mm ( 3 ⁄ 64  in) diameter while most wire ropes begin at a 6.4 mm ( 1 ⁄ 4  in) diameter. Static wire ropes are used to support structures such as suspension bridges or as guy wires to support towers. An aerial tramway relies on wire rope to support and move cargo overhead. Modern wire rope

2135-693: The combination of technologies created a stiffer bridge. John A. Roebling took particular advantage of this to limit deformations due to railway loads in the Niagara Falls Suspension Bridge . The earliest known surviving example of a true cable-stayed bridge in the United States is E.E. Runyon's largely intact steel or iron Bluff Dale Suspension bridge with wooden stringers and decking in Bluff Dale, Texas (1890), or his weeks earlier but ruined Barton Creek Bridge between Huckabay, Texas and Gordon, Texas (1889 or 1890). In

2196-406: The design of rope drives for cranes, elevators, rope ways and mining installations. Factors that are considered in design include: The calculation of the rope drive limits depends on: The wire ropes are stressed by fluctuating forces, by wear, by corrosion and in seldom cases by extreme forces. The rope life is finite and the safety is only ensured by inspection for the detection of wire breaks on

2257-572: The design, the columns may be vertical or angled or curved relative to the bridge deck. A side-spar cable-stayed bridge uses a central tower supported only on one side. This design allows the construction of a curved bridge. Far more radical in its structure, the Puente del Alamillo (1992) uses a single cantilever spar on one side of the span, with cables on one side only to support the bridge deck. Unlike other cable-stayed types, this bridge exerts considerable overturning force upon its foundation and

2318-403: The entire bridge was planned to open by the end of the year. Despite the concrete part of the bridge being open to I-30 traffic, the arched pedestrian and bicycle bridges remained closed, due to concerns with cables that connect the arch to the base of the bridges, and their resistance to heavy winds. When they vibrate from these winds, this has resulted in multiple incidents where the stress from

2379-436: The ground. This can be difficult to implement when ground conditions are poor. The main cables, which are free to move on bearings in the towers, bear the load of the bridge deck. Before the deck is installed, the cables are under tension from their own weight. Along the main cables smaller cables or rods connect to the bridge deck, which is lifted in sections. As this is done, the tension in the cables increases, as it does with

2440-624: The individual wires were wrapped around the centers in one direction and the strands were wrapped around the core in the opposite direction. Multi-strand ropes are all more or less resistant to rotation and have at least two layers of strands laid helically around a centre. The direction of the outer strands is opposite to that of the underlying strand layers. Ropes with three strand layers can be nearly non-rotating. Ropes with two strand layers are mostly only low-rotating. Depending on where they are used, wire ropes have to fulfill different requirements. The main uses are: Technical regulations apply to

2501-456: The life of the rope, it also helps to compensate for minor failures in the short run. Wire ropes were developed starting with mining hoist applications in the 1830s. Wire ropes are used dynamically for lifting and hoisting in cranes and elevators , and for transmission of mechanical power . Wire rope is also used to transmit force in mechanisms, such as a Bowden cable or the control surfaces of an airplane connected to levers and pedals in

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2562-412: The load on a relatively small area. A thimble can be installed inside the loop to preserve the natural shape of the loop, and protect the cable from pinching and abrading on the inside of the loop. The use of thimbles in loops is industry best practice . The thimble prevents the load from coming into direct contact with the wires. A wire rope clip, sometimes called a clamp, is used to fix the loose end of

2623-530: The loop back to the wire rope. It usually consists of a U-bolt , a forged saddle, and two nuts. The two layers of wire rope are placed in the U-bolt. The saddle is then fitted to the bolt over the ropes (the saddle includes two holes to fit to the U-bolt). The nuts secure the arrangement in place. Two or more clips are usually used to terminate a wire rope depending on the diameter. As many as eight may be needed for

2684-505: The outer layer is supported by two wires of the inner layer. These wires are neighbors along the whole length of the strand. Parallel lay strands are made in one operation. The endurance of wire ropes with this kind of strand is always much greater than of those (seldom used) with cross lay strands. Parallel lay strands with two wire layers have the construction Filler, Seale or Warrington. In principle, spiral ropes are round strands as they have an assembly of layers of wires laid helically over

2745-399: The process further. In America wire rope was manufactured by John A. Roebling , starting in 1841 and forming the basis for his success in suspension bridge building. Roebling introduced a number of innovations in the design, materials and manufacture of wire rope. Ever with an ear to technology developments in mining and railroading, Josiah White and Erskine Hazard , principal owners of

2806-547: The pylons; Millau Viaduct and Mezcala Bridge , where twin-legged towers are used; and General Rafael Urdaneta Bridge , where very stiff multi-legged frame towers were adopted. A similar situation with a suspension bridge is found at both the Great Seto Bridge and San Francisco–Oakland Bay Bridge where additional anchorage piers are required after every set of three suspension spans – this solution can also be adapted for cable-stayed bridges. An extradosed bridge

2867-517: The relative price of these designs. Cable-stayed bridges date back to 1595, where designs were found in Machinae Novae , a book by Croatian - Venetian inventor Fausto Veranzio . Many early suspension bridges were cable-stayed construction, including the 1817 footbridge Dryburgh Abbey Bridge , James Dredge 's patented Victoria Bridge, Bath (1836), and the later Albert Bridge (1872) and Brooklyn Bridge (1883). Their designers found that

2928-405: The rope and are always placed against the live end. The US Navy and most regulatory bodies do not recommend the use of such clips as permanent terminations unless periodically checked and re-tightened. An eye splice may be used to terminate the loose end of a wire rope when forming a loop. The strands of the end of a wire rope are unwound a certain distance, then bent around so that the end of

2989-522: The self-anchored type lacks the heavy cable anchorages of the ordinary suspension bridge. Unlike either a cable-stayed bridge or a suspension bridge, the self-anchored suspension bridge must be supported by falsework during construction and so it is more expensive to construct. Wire rope In stricter senses, the term wire rope refers to a diameter larger than 9.5 mm ( 3 ⁄ 8  in), with smaller gauges designated cable or cords. Initially wrought iron wires were used, but today steel

3050-403: The socket, wrapped around a separate component called the wedge. The arrangement is knocked in place, and load gradually eased onto the rope. As the load increases on the wire rope, the wedge become more secure, gripping the rope tighter. Poured sockets are used to make a high strength, permanent termination; they are created by inserting the wire rope into the narrow end of a conical cavity which

3111-512: The spar must resist the bending caused by the cables, as the cable forces are not balanced by opposing cables. The spar of this particular bridge forms the gnomon of a large garden sundial . Related bridges by the architect Santiago Calatrava include the Puente de la Mujer (2001), Sundial Bridge (2004), Chords Bridge (2008), and Assut de l'Or Bridge (2008). Cable-stayed bridges with more than three spans involve significantly more challenging designs than do 2-span or 3-span structures. In

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3172-530: The throughput of the coal capacity since return of cars dropped from nearly four hours to less than 20 minutes. The following decades featured a burgeoning increase in deep shaft mining in both Europe and North America as surface mineral deposits were exhausted and miners had to chase layers along inclined layers. The era was early in railroad development and steam engines lacked sufficient tractive effort to climb steep slopes, so inclined plane railways were common. This pushed development of cable hoists rapidly in

3233-411: The towers. That has the disadvantage, unlike for the suspension bridge, that the cables pull to the sides as opposed to directly up, which requires the bridge deck to be stronger to resist the resulting horizontal compression loads, but it has the advantage of not requiring firm anchorages to resist the horizontal pull of the main cables of the suspension bridge. By design, all static horizontal forces of

3294-529: The twentieth century, early examples of cable-stayed bridges included A. Gisclard's unusual Cassagnes bridge (1899), in which the horizontal part of the cable forces is balanced by a separate horizontal tie cable, preventing significant compression in the deck, and G. Leinekugel le Coq's bridge at Lézardrieux in Brittany (1924). Eduardo Torroja designed a cable-stayed aqueduct at Tempul in 1926. Albert Caquot 's 1952 concrete-decked cable-stayed bridge over

3355-410: The unwrapped length forms an eye. The unwrapped strands are then plaited back into the wire rope, forming the loop, or an eye, called an eye splice. A Flemish eye, or Dutch Splice, involves unwrapping three strands (the strands need to be next to each other, not alternates) of the wire and keeping them off to one side. The remaining strands are bent around, until the end of the wire meets the "V" where

3416-422: The unwrapping finished, to form the eye. The strands kept to one side are now re-wrapped by wrapping from the end of the wire back to the "V" of the eye. These strands are effectively rewrapped along the wire in the opposite direction to their original lay. When this type of rope splice is used specifically on wire rope, it is called a "Molly Hogan", and, by some, a "Dutch" eye instead of a "Flemish" eye. Swaging

3477-409: The vibrations caused several cable anchor rods to fail. Furthermore, the stress has also caused the bridges to crack significantly and resulted in multiple occasions in which rods were cracked and twisted, with the small diameter of the rods resulting on putting more stress on them. The lack of testing and the multiple issues plaguing the bridges led to a large dispute; Calatrava blamed the contractor for

3538-479: The wires can be right (symbol z) or left (symbol s). This kind of rope is called ordinary lay rope if the lay direction of the wires in the outer strands is in the opposite direction to the lay of the outer strands themselves. If both the wires in the outer strands and the outer strands themselves have the same lay direction, the rope is called a lang lay rope (from Dutch langslag contrary to kruisslag , formerly Albert's lay or langs lay). Regular lay means

3599-634: Was invented by the German mining engineer Wilhelm Albert in the years between 1831 and 1834 for use in mining in the Harz Mountains in Clausthal , Lower Saxony , Germany . It was quickly accepted because it proved superior strength from ropes made of hemp or of metal chains , such as had been used before. Wilhelm Albert's first ropes consisted of three strands consisting of four wires each. In 1840, Scotsman Robert Stirling Newall improved

3660-574: Was named for Margaret McDermott, an area philanthropist . As part of the Trinity River Project and Horseshoe Project , the Margaret McDermott Bridge was one of three new Santiago Calatrava -designed bridges planned to cross the Trinity River . However, plans for the McDermott Bridge were scaled back, and plans for a third bridge along I-35E were scrapped, due to budget issues. On December 12, 2005, construction of

3721-458: Was still scheduled to perform the design work. After delays, construction on the bridge began in 2012, costing over $ 200 million. Specifically, the arched pedestrian and bicycle bridges cost $ 115 million, while the actual freeway bridge was paid for by the state and cost an additional $ 120 million. The main concrete part of the bridge, which carries I-30 traffic, opened in 2013. The 1,200-foot-long (370 m) steel suspension arches on both sides of

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