Gladesville Bridge - AbsoluteAstronomy.com

Gladesville Bridge is an arch bridge

Arch bridge

An arch bridge is a bridge with abutments at each end shaped as a curved arch. Arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side...

near Gladesville that spans the Parramatta River

Parramatta River

The Parramatta River is a waterway in Sydney, New South Wales, Australia. The Parramatta River is the main tributary of Sydney Harbour, a branch of Port Jackson, along with the smaller Lane Cove and Duck Rivers....

, west of central Sydney

Sydney

Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...

, Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

. It links the suburbs of Huntleys Point

Huntleys Point, New South Wales

Huntleys Point is a suburb on the Lower North Shore of Sydney, in the state of New South Wales, Australia. Huntleys Point is located 9 kilometres north-west of the Sydney central business district, in the local government area of the Municipality of Hunter's Hill...

and Drummoyne

Drummoyne, New South Wales

Drummoyne is a suburb in the inner west of Sydney, in the state of New South Wales, Australia. It is located 6 kilometres west of the Sydney central business district and is the administrative centre for the local government area of the City of Canada Bay....

. It is a few kilometres upstream of the more famous Sydney Harbour Bridge

Sydney Harbour Bridge

The Sydney Harbour Bridge is a steel through arch bridge across Sydney Harbour that carries rail, vehicular, bicycle and pedestrian traffic between the Sydney central business district and the North Shore. The dramatic view of the bridge, the harbour, and the nearby Sydney Opera House is an iconic...

and is part of Victoria Road

Victoria Road, Sydney

Victoria Road is a major road in Sydney, Australia.Victoria Road connects Parramatta with the Rozelle end of Anzac Bridge. Victoria Road passes through the Sydney suburbs of Rydalmere, Ermington, West Ryde, Ryde, Gladesville and Drummoyne and is currently one of the longest roads in Sydney.The road...

. At the time of its completion in 1964, Gladesville Bridge was the longest single span concrete

Concrete

Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

arch

Arch

An arch is a structure that spans a space and supports a load. Arches appeared as early as the 2nd millennium BC in Mesopotamian brick architecture and their systematic use started with the Ancient Romans who were the first to apply the technique to a wide range of structures.-Technical aspects:The...

ever constructed. Gladesville Bridge is the largest of a complex of three bridges, including Fig Tree Bridge

Fig Tree Bridge

Fig Tree Bridge is a girder bridge that spans the Lane Cove River, west of the CBD in Sydney, Australia. It is immediately to the north of Tarban Creek Bridge and the more well-known Gladesville Bridge...

and Tarban Creek Bridge

Tarban Creek Bridge

Tarban Creek Bridge is an arch bridge that spans Tarban Creek, west of central Sydney, Australia. It is located between Gladesville Bridge and Fig Tree Bridge, being immediately to the north of Gladesville Bridge...

, designed to carry traffic as part of the North Western Expressway

North Western Expressway

The North Western Expressway was a planned freeway route in Sydney, New South Wales, Australia, intended to link the Sydney CBD to its north-western suburbs, and ultimately the F3 Freeway to Newcastle....

. The bridge was the first phase of this freeway project that was to connect traffic from the Newcastle via Wahroonga/Lane Cove, then through Glebe/Annandale 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.

1881 bridge

The current bridge replaced the original Gladesville Bridge (Parramatta River Bridge), which was opened on 1 February 1881.
The old Gladesville Bridge was constructed as part of a series of bridges built during the 1880s, which also saw the construction of the Fig Tree Bridge

Fig Tree Bridge

and the Iron Cove Bridge

Iron Cove Bridge, New South Wales

Iron Cove Bridge is a heritage listed bridge linking the suburbs of Drummoyne to Rozelle in New South Wales, Australia.-Original:The original bridge was constructed of wrought iron lattice girders and opened in 1882 after four years of construction...

. It was the only crossing of the Parramatta River east of Parramatta at the time of construction, with punts and ferries (steamers) providing the main methods of crossing the river. The closest crossing to the bridge was the Bedlam Punt, which operated from 1829 through to 1881 between Punt Road in the present-day Gladesville and the Great North Road in present-day Abbotsford.

The 1881 Gladesville Bridge was about 300 metres (980 ft) to the west of the modern bridge. This original bridge only carried one lane of traffic in each direction as well as a tramway. It featured a swing section on the southern end of the bridge that could be opened to permit sailing ships and steamers with high funnels to pass. Colliers from Newcastle would require the bridge to be opened to gain access to the Australian Gas Light Company (AGL) gasworks site at Mortlake

Mortlake, New South Wales

Mortlake is a suburb in the inner-west of Sydney, in the state of New South Wales, Australia. Mortlake is located 17 kilometres west of the Sydney central business district, in the local government area of the City of Canada Bay.-Transport:...

, (now redeveloped as Breakfast Point

Breakfast Point, New South Wales

Breakfast Point is a suburb of Sydney, New South Wales, Australia. Breakfast Point is located 16 kilometres west of the Sydney central business district...

). The bridge stood on iron cylinders with a sandstone pier at each end of the bridge. The sandstone piers are all that remain today of the original bridge, with the northern pier adjacent to the Huntleys Point Ferry Wharf, and the southern in Howley Park in Drummoyne.

Current bridge

The 1964 bridge was planned and commenced as traffic demands were rising steadily in the 1950s. In addition to the old bridge often becoming a one-way crossing during peak periods, and it being used by trams, there were also several occasions during the 1960s when it could no longer be re-closed, having expanded when open due to extreme heat conditions. Construction on the new bridge started in December 1959, and took five years to complete. It was officially opened by Princess Marina

Princess Marina, Duchess of Kent

Princess Marina, Duchess of Kent, née Princess Marina of Greece and Denmark was a member of the British Royal Family; the wife of Prince George, Duke of Kent, the fourth son of King George V of the United Kingdom and Mary of Teck....

on 2 October 1964.

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.

Design and Construction

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 such a high clearance.

The design

Design

Design as a noun informally refers to a plan or convention for the construction of an object or a system while “to design” refers to making this plan...

of the bridge was both daring and untried, yet in many ways echoed the Roman

Ancient Rome

Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

method of building arches using segmented units built over a temporary formwork

Formwork

Formwork is the term given to either temporary or permanent molds into which concrete or similar materials are poured. In the context of concrete construction, the falsework supports the shuttering moulds.-Formwork and concrete form types:...

. In Gladesville's case, these were hollow precast concrete

Precast concrete

By producing precast concrete in a controlled environment , the precast concrete is afforded the opportunity to properly cure and be closely monitored by plant employees. Utilizing a Precast Concrete system offers many potential advantages over site casting of 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

Rubber

Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...

gasket

Gasket

s were inserted. When all of the blocks in the arch (there are four parallel

Parallel (geometry)

Parallelism is a term in geometry and in everyday life that refers to a property in Euclidean space of two or more lines or planes, or a combination of these. The assumed existence and properties of parallel lines are the basis of Euclid's parallel postulate. Two lines in a plane that do not...

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

Sandstone

Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

bedrock on either side of the river.

The bridge as originally tendered for this location was a rather conventional steel

Steel

Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

cantilever bridge

Cantilever bridge

A cantilever bridge is a bridge built using cantilevers, structures that project horizontally into space, supported on only one end. For small footbridges, the cantilevers may be simple beams; however, large cantilever bridges designed to handle road or rail traffic use trusses built from...

, but one of the contractors tendered the alternative catenary

Catenary

In physics and geometry, the catenary is the curve that an idealised hanging chain or cable assumes when supported at its ends and acted on only by its own weight. The curve is the graph of the hyperbolic cosine function, and has a U-like shape, superficially similar in appearance to a parabola...

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

Engineer

An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics and ingenuity to develop solutions for technical problems. Engineers design materials, structures, machines and systems while considering the limitations imposed by practicality,...

Eugène Freyssinet

Eugène Freyssinet was a French structural and civil engineer. He was the major pioneer of prestressed concrete.Freyssinet was born in at Objat, Corrèze, France. He worked in the École Nationale des Ponts et Chaussées in Paris, France where he designed several bridges until the First World War...

, who approved the design with recommendations. The inflatable gasket method for example had been pioneered by Freyssinet on much earlier designs.

External links

Roads & Traffic Authority, NSW Web Cam

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