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24-707: The Mooney Mooney Bridge , officially the Mooney Mooney Creek Bridge , and popularly known as The NSW Big Dipper Bridge , is a twin cantilever bridge that carries the Pacific Motorway (M1) across Mooney Mooney Creek , located near Mooney Mooney in the Brisbane Water National Park on the Central Coast of New South Wales , Australia. The concrete box girder bridge was opened on 14 December 1986 by

48-423: A balanced cantilever ; when they attach to a solid foundation, the counterbalancing arms are called anchor arms . Thus, in a bridge built on two foundation piers, there are four cantilever arms: two which span the obstacle, and two anchor arms that extend away from the obstacle. Because of the need for more strength at the balanced cantilever's supports, the bridge superstructure often takes the form of towers above

72-505: A bridge that could handle differential settlement of the foundations. Engineers could more easily calculate the forces and stresses with a hinge in the girder. Heinrich Gerber was one of the engineers to obtain a patent for a hinged girder (1866) and is recognized as the first to build one. The Hassfurt Bridge over the Main river in Germany with a central span of 124 feet (38 metres)

96-731: A new high-speed freeway-style traffic link between Wahroonga and Beresfield began in 1952, it was not until April 1963 when construction of the first section of the F3 Pacific Freeway started, between the Hawkesbury River and Mount White , completed in December 1965. A second stage from Mount White to Calga was completed in October 1966. South of the Hawkesbury River, the freeway-grade section to Berowra

120-453: A result, a fence was erected along the side of the bridge to prevent people jumping off. This fence was erected in 2003 and cost A$ 1,000,000. Cantilever bridge The steel truss cantilever bridge was a major engineering breakthrough when first put into practice, as it can span distances of over 1,500 feet (450 m), and can be more easily constructed at difficult crossings by virtue of using little or no falsework . Engineers in

144-422: A stabilizing web , but may also have a box shape, Z shape, or other forms. Girders are commonly used to build bridges. A girt is a vertically aligned girder placed to resist shear loads. Small steel girders are rolled into shape. Larger girders (1 m/3 feet deep or more) are made as plate girders , welded or bolted together from separate pieces of steel plate . The Warren type girder replaces

168-474: A standard in the design of bridges throughout New South Wales. They employ a two rail parapet which optimises views of the landscape. The bridges were designed with the natural surroundings in mind and form a simple uncluttered shape so not to detract from the natural bushland of the national park. The three span haunched girders on the bridge were critical to this as were the multiple piers that provide character and strength. The Mooney Mooney Bridge has been

192-479: Is available to support the tension in the upper chord of the span during construction, usually limiting this method to the spanning of narrow canyons. World's longest cantilever bridges (by longest span): Girder A girder ( / ˈ ɡ ɜːr d ər / ) is a beam used in construction . It is the main horizontal support of a structure which supports smaller beams. Girders often have an I-beam cross section composed of two load-bearing flanges separated by

216-465: The Navajo Bridge ) are built using pure cantilever spans from each side, with neither falsework below nor temporary supporting towers and cables above. These are then joined with a pin, usually after forcing the union point apart, and when jacks are removed and the bridge decking is added the bridge becomes a truss arch bridge . Such unsupported construction is only possible where appropriate rock

240-762: The Prime Minister of Australia , Bob Hawke , and is owned and maintained by Transport for NSW , an agency of the Government of New South Wales . The Pacific Motorway is the main road link between Sydney , the Central Coast and the Hunter Region . The only other road that links all three regions is the Pacific Highway (B83) which from Cowan to Kariong follows a scenic winding route. The Pacific Highway (now known as B83) served as

264-435: 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 hinge in the multi-span system presented the advantages of a statically determinate system and of

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288-473: The Pacific Highway at Doyalson . The 15-kilometre-long (9 mi) section between Calga and Somersby, including the new Mooney Mooney Creek bridge was opened on 14 December 1986, as thousands of people walked across the twin bridges. The freeway carried two lanes heading north and two lanes heading south. Additional developments were made as follows: Mooney Mooney Bridge was designed by Bruce Judd of

312-415: The action of the outer foundations. Cantilever Bridge.—A structure at least one portion of which acts as an anchorage for sustaining another portion which extends beyond the supporting pier. A simple cantilever span is formed by two cantilever arms extending from opposite sides of an obstacle to be crossed, meeting at the center. In a common variant, the suspended span , the cantilever arms do not meet in

336-423: The center; instead, they support a central truss bridge which rests on the ends of the cantilever arms. The suspended span may be built off-site and lifted into place, or constructed in place using special travelling supports. A common way to construct steel truss and prestressed concrete cantilever spans is to counterbalance each cantilever arm with another cantilever arm projecting the opposite direction, forming

360-648: The foundation piers. The Commodore Barry Bridge is an example of this type of cantilever bridge. Steel truss cantilevers support loads by tension of the upper members and compression of the lower ones. Commonly, the structure distributes the tension via the anchor arms to the outermost supports, while the compression is carried to the foundations beneath the central towers. Many truss cantilever bridges use pinned joints and are therefore statically determinate with no members carrying mixed loads. Prestressed concrete balanced cantilever bridges are often built using segmental construction . Some steel arch bridges (such as

384-582: The only highway route between Sydney and the Central Coast and the Hunter Region. The original 1930 two-lane steel truss bridge carried the Old Pacific Highway across Mooney Mooney Creek. This bridge remains in concurrent use and is located downstream of the existing Mooney Mooney Bridge. With population and traffic growth, the scenic winding highway route was beset by traffic jams, especially at peak holiday times. Whilst planning for

408-434: The other side of the bridge. This accident resulted in the death of a woman. On 12 February 2007 another accident occurred when a truck was travelling down the freeway and lost control approaching the bridge, smashing through a guard rail and plunging 30 metres down an embankment at the side of the bridge. The Mooney Mooney Bridge, because of its height, has been susceptible in the past to people committing suicide. As

432-526: The site of several accidents , resulting in the Pacific Motorway being closed to traffic and causing delays. Some of these accidents have prompted debate on whether a new road should be built to supplement the existing freeway. On 23 October 2004 a semi-trailer 's brakes failed coming down the Freeway and caused a pile-up involving 35 vehicles that had slowed down as a result of a car accident on

456-489: The solid web with an open latticework truss between the flanges. This arrangement combines strength with economy of materials, minimizing weight and thereby reducing loads and expense. Patented in 1848 by its designers James Warren and Willoughby Theobald Monzani, its structure consists of longitudinal members joined only by angled cross-members, forming alternately inverted equilateral triangle -shaped spaces along its length, ensuring that no individual strut , beam, or tie

480-431: The structural principles of the suspended span cantilever by sitting in chairs and supporting their colleague, Kaichi Watanabe , in between them, using just their arms and wooden poles. The suspended span, where Watanabe sits, is in the center. The wooden poles resist the compression of the lower chord , while the outstretched arms support the tension of the upper chord. The placement of the brick counterweights demonstrates

504-571: The then NSW Department of Main Roads and built by Enpro Constructions by the free cantilever method of post tensioned concrete. It consists of twin bridges, each bridge with a main span and two approach spans. The span at the western end of the bridge is 135 metres (443 ft) long, the main span is 220 metres (722 ft) long and the eastern span is 131 metres (430 ft) long. The design has been said to demonstrate how good engineering design and good aesthetics are synonymous, and has been used as

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528-574: Was 275 feet (84 metres) deep and took full advantage of the fact that falsework, or temporary support, is not needed for the main span of a cantilever bridge. The Forth Bridge is a notable example of an early cantilever bridge. This bridge held the record for longest span in the world for twenty-nine years until it was surpassed by the Quebec Bridge . The engineers responsible for the bridge, Sir Benjamin Baker and Sir John Fowler , demonstrated

552-550: Was completed in 1867 and is recognized as the first modern cantilever bridge. The High Bridge of Kentucky by C. Shaler Smith (1877), the Niagara Cantilever Bridge by Charles Conrad Schneider (1883) and the Poughkeepsie Bridge by John Francis O'Rourke and Pomeroy P. Dickinson (1889) were all important early uses of the cantilever design. The Kentucky River Bridge spanned a gorge that

576-618: Was completed in December 1968, as a toll road . In October 1973 the Peats Ferry Bridge was duplicated as the Brooklyn Bridge , connecting the Berowra-Hawkesbury River and Hawkesbury River-Calga sections. Concurrently, the freeway was opened from Somersby to Ourimbah and Kangy Angy to Wallarah Creek sections in December 1983, including the single carriageway motorway link from Wallarah Creek to

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