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30-680: The Leonard P. Zakim ( / ˈ z eɪ k ə m / ) Bunker Hill Memorial Bridge (also known as "The Zakim" ) is a cable-stayed bridge completed in 2003 across the Charles River in Boston , Massachusetts . It is a replacement for the Charlestown High Bridge , an older truss bridge constructed in the 1950s. The bridge and connecting tunnel were built as part of the Big Dig , the largest highway construction project in

60-460: 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

90-679: 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

120-507: 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

150-608: 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

180-486: 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

210-464: The United States . The bridge's unique styling quickly became an icon for Boston, often featured in the backdrop of national news channels, to establish location, and included on tourist souvenirs. The bridge is commonly referred to as the " Zakim Bridge " or " Bunker Hill Bridge " by residents of nearby Charlestown . The Leverett Circle Connector Bridge was constructed in conjunction with

240-451: 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

270-507: 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

300-707: The Lost Half Mile. Pedestrians and cyclists are able to travel from Charlestown toward Cambridge over the adjacent North Bank Bridge to North Point Park . This bridge is a link in the Charles River Bike Path and a segment of the Mass Central Rail Trail and the East Coast Greenway . Cable-stayed bridge A cable-stayed bridge has one or more towers (or pylons ), from which cables support

330-636: 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

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360-502: The Zakim Bridge, allowing some traffic to bypass it. The bridge concept was designed by Swiss civil engineer Christian Menn in collaboration with bridge designer Miguel Rosales and its design was engineered by American civil engineer Ruchu Hsu with Parsons Brinckerhoff. Wallace Floyd Associates, sub-consultants to Bechtel/Parsons Brinckerhoff, was the lead architect/urban designer and facilitated community participation during

390-409: 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

420-500: The bridge. The bridge's full name commemorates Boston area leader and civil rights activist Leonard P. Zakim , who championed "building bridges between peoples", and the Battle of Bunker Hill . The bridge was dedicated on October 4, 2002, in a ceremony held on the new span. The dedication speakers included members of Zakim's family, government officials, and a performance of the song " Thunder Road " by Bruce Springsteen . Introducing

450-405: 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

480-562: 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

510-702: The cables, which carry northbound traffic from the Sumner Tunnel and North End on-ramp. These lanes merge with the main highway north of the bridge. I-93 heads toward New Hampshire as the "Northern Expressway", and US 1 splits from the Interstate and travels northeast toward Massachusetts' North Shore communities, crossing the Mystic River via the Tobin Bridge . The 1975-built MBTA Orange Line's Haymarket North Extension tunnel lies beneath

540-739: The city of Boston ). It crosses the MBTA Commuter Rail tracks leading into North Station , crosses the Millers River , and goes under the highway lanes of the Leverett Connector and Route 1 . It lands on the east side of the Millers River under the Zakim Bridge / Interstate 93 , where it connects to Paul Revere Park in Charlestown . The state-owned bridge opened in 2012. This article about

570-693: 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

600-402: The contour of the Charles River shoreline. The process of landscape design and environmental mitigation under the bridge deck and around the bridge supports allowed for the creation of a new and accessible public landscape designed by Carol R. Johnson Associates. This under bridge landscape contains a series of perforated stainless steel lighting-based public artworks, entitled, Five Beacons for

630-477: The design process. The bridge is a cable-stayed bridge in a harp configuration with cradles carrying each strand through their pylon. The main portion of the Zakim Bridge carries four lanes each way (northbound and southbound) of Interstate 93 ( concurrent with U.S. Route 1 ) between the Thomas P. "Tip" O'Neill Jr. Tunnel and the elevated highway to the north. Two additional lanes are cantilevered outside

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660-572: 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

690-436: 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

720-547: 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

750-517: 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

780-491: 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. North Bank Bridge The bridge leaves the ground from the east side of the Cambridge portion of North Point Park (other parts of which are in

810-462: The song, Springsteen said about Zakim, "... I knew him a little bit during the last year of his life, he was one of those people whose, intensity, inner spirit you could feel even when he was very ill, ... we honor his memory obviously not with this beautiful bridge, very lovely, but by continuing on in his fight for social justice." Placement of footings for the Zakim Bridge required environmental permits to relocate areas of open water surface, changing

840-512: 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

870-411: 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

900-529: 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

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