Сиднейдегі Гладесвилл көпірі

Bridge in Sydney, Australia

Gladesville Bridge is a heritage listed concrete arch road bridge that carries Victoria Road over the Parramatta River, linking the Sydney suburbs of Huntleys Point and Drummoyne, in the local government areas of Canada Bay and Hunter's Hill, in New South Wales, Australia. Despite its name, the bridge is not in Gladesville. The Gladesville Bridge is a few kilometres upstream of the famous Sydney Harbour Bridge. When it was completed in 1964, Gladesville Bridge was the longest single span concrete arch ever constructed. Gladesville Bridge is the largest of a complex of three bridges, including Fig Tree Bridge and Tarban Creek Bridge, designed to carry traffic as part of the North Western Expressway. The bridge was the first phase of this freeway project that was to connect traffic from the via /Lane Cove, then through / to connect into the city. Due to community action the freeway project was abandoned by the Wran Government in 1977, leaving the Gladesville Bridge connecting the existing arterial roads. The Gladesville Bridge was designed by Anthony Gee, G. Maunsell & Partners and Eugène Freyssinet and built from 1959 to 1964 by Reed & Mallik (Engineers, England) and Stuart Bros (Builders, Sydney). The property is owned by Transport for NSW. The bridge was added to the New South Wales State Heritage Register on 1 October 2014.

By the 1950s, due to a rapid growth in private car ownership and road freight transport in Sydney during the interwar and post World War 2 period, the traffic crossing the old Gladesville Bridge was becoming increasingly congested. With consistent interruptions and delays from the tramline and from shipping transportation along the Parramatta River, it was soon realised that a new bridge was required to alleviate the problem. In the late 1950s, the Department of Main Roads (DMR) intended the replacement Gladesville Bridge to be a conventional steel truss of its own design. However, an alternative approach, prepared by English civil engineering firm G. Maunsell & Partners, was soon submitted by another English firm, Reed & Mallik Ltd which had teamed up with Sydney based builders Stuart Brothers. The bridge was originally opened with six traffic lanes, but the extra wide outer lanes enabled a later reconfiguration to take place. The bridge now has three northbound lanes and four southbound lanes, separated by a concrete median.

At the time when the bridge was planned, it was anticipated that extremely large vessels would need to pass underneath it in the years to come. This, as well as the topography of the site, explains why the bridge was designed with a high 61 metre (200 ft) clearance. The construction of the new Gladesville Bridge was a noteworthy engineering achievement for its time and, being both daring and untried, its innovative design and construction set several new standards on the international stage. In many ways the construction echoed the Roman method of building arches using segmented units built over a temporary formwork. In Gladesville's case, these were hollow precast concrete blocks which were hoisted up from barges on the river, then moved down a railway on the top of the formwork into position. Every few blocks, special inflatable rubber gaskets were inserted. When all of the blocks in the arch (there are four parallel arches altogether, not seen in the picture) were in place, the gaskets were 'inflated' using synthetic hydraulic fluid, expanding the entire arch and lifting it away from the formwork to support its own weight. Once adjusted to the correct position, the gaskets were filled with liquid concrete, driving out the oil and setting to form a permanent solid arch. The formwork was then moved sideways and the next arch constructed in the same fashion. Once all four arches were erected, the deck was laid on top built from further precast concrete units. The arches bed into solid sandstone bedrock on either side of the river. The bridge as originally tendered for this location was a rather conventional steel cantilever bridge, but one of the contractors tendered the alternative catenary arch design, recognising it was pushing the envelope of existing bridge building knowledge. The contractor's designer was G Maunsell & Partners of London. Their alternative was accepted after submission to the famous bridge engineer Eugène Freyssinet, who approved the design with recommendations. The inflatable gasket method for example had been pioneered by Freyssinet on much earlier designs. Gladesville Bridge was the first 1000 feet (305 m) span concrete bridge in the world and had a substantial number of engineering and technical elements that made it a world leading bridge design and construction achievement. It was also the first bridge, if not one of the first bridges, to utilise computer programming in its construction. As there was no suitable proprietary engineering software available at that time, the bridge designer (Anthony Gee of G. Maunsell & Partners) also wrote a suite of five computer programs for analysis and detailed design to guide its construction.