Right in the heart of the Sydney central business district rises the 305-metre Sydney Tower, a distinctive, highly visible Sydney landmark and the city’s tallest structure, more than two and a quarter times the height of the Sydney Harbour Bridge at its highest point.

Sydney Tower provides an aerie-like platform to view Sydney and its surrounds. On a clear day, you can see as far as the Central Coast in the north, the Blue Mountains in the west and Wollongong and the Illawarra Coast in the south.

But Sydney Tower is not just a landmark, an observation deck, and a point of reference for those who lose their way in the city. It is a dining venue with its revolving restaurants, a source of dynamic audiovisual Australian information with its OzTrek attraction, and beneath it a constellation of shops in the Westfield Centrepoint shopping centre.

Sydney Tower was officially opened on 27th September 1981, with construction having started seven years earlier. Built to withstand earthquakes and gale-force winds experienced only once every thousand years, Sydney Tower is a towering testimonial to the work of architect Donald Crone whose vision it was to create this landmark "needle" in the sky.

The turret of Sydney Tower is equivalent in size to that of a nine-storey building. It can accommodate a maximum 960 people and is serviced by three high-speed elevators. Fifty-six steel cables stabilise the tower.

There is some confusion about its name as many Sydneysiders refer to this structure as Centrepoint Tower. Then there was the time it was called AMP Tower (after its owners) with the letters AMP emblazoned on the turret’s sides. Whatever it has been called before, and there are mentions of Centrepoint Tower in a number of travel guidebooks as well as in certain street directories, it is now officially called Sydney Tower. Centrepoint Tower, AMP Tower and Sydney Tower are not separate structures but the one same towering Sydney landmark.

Because it is visible from many parts of the city, Sydney Tower has been used to highlight city events, particularly the 2000 Sydney Olympics, when wire figures of Olympic athletes were installed on it.

The tower has a capacity of 960 persons, and contains two levels of restaurants, a coffee lounge, an Observation Deck, two telecommunication transmission levels and three plant levels. To get there you can travel in one of three high speed double deck Lifts take approximately 40 seconds to travel from top to bottom or if you register for the annual Sydney Tower Run-Up you can get there by climbing 1504 stairs. Climbing the steps in the Tower’s emergency staircase would take an average person 50 exhausting minutes. However, the fastest stair climber on record clocked just 6 minutes 52 seconds  for the dash to the top as part of Sydney Tower  tower’s annual ‘Run Up’ race.

On a clear day, visitors to the Tower can see landforms up to 85 km away from the observation deck, embracing the Blue Mountains to the west, the Central Coast to the north and the Illawarra escarpment to the south. Visitors can see 55km out to sea compared to someone at Bondi Beach who can see just 5km to the horizon. This means a Tower observer can see a ship approaching Sydney two hours before the person at the beach.

When it opened in September 1981, Sydney Tower was the fourth tallest building in the world. The 4067-tonne tower is constructed on the massive 50,000 tonne Centrepoint shopping centre. Sydney Tower’s shaft consists of 46 separate pre- fabricated barrel units made of high strength weathering steel (called AUSTEN 50), used extensively for the first time in Australia when constructed.
 
The weathered effect on the structure is caused by special alloying elements which react with the air to form a dense tight oxide film to protect the steel from corrosion. The appearance, texture and maturity of the weathered steel’s patina depends upon three primary natural factors - time, the degree of exposure and atmospheric environment. With time, the oxide coating changes from a rusty red-orange to a dark purple-brown. 

Sydney Tower’s shaft is secured by 56 cables – each 182 metres long and made up of 235 high tensile wires no wider than a fingernail.  The cables form a hyperbolic paraboloid around the Tower’s steel shaft & weigh 700 tonnes. If the wires in the Tower’s 56 securing tables were laid end to end they would stretch 2395 kilometres. This is the same distance as Melbourne to Cairns, or London to Athens. And it’s further than Auckland to Sydney, Los Angeles to Houston, or Tokyo to Beijing.

The Tower’s central column is 6.7 metres in diameter. In a true engineering feat, Sydney Tower’s turret was assembled around the bottom of the shaft then lifted hydraulically by 24 100-tonne jacks at the rate of nine metres a week until it reached its final position. The turret is home to a 162,000 water tank which acts as a stabiliser against wind movement and supports the Tower’s fire sprinkler system. If the tank held paint, it would be enough to give the Harbour Bridge two more top coats. Sydney Tower sports 420 windows which takes an automatic window machine (named “Charlie”) two days to clean. (Charlie doesn’t work nights.)

Sydney Tower is designed to withstand winds of up to 172 kmh, & even at this wind speed it would only sway to a maximum of one metre. Testing was done in the aeronautical wind tunnel at Sydney University & then with an aeroelastic model at the University of  Western Ontario, Canada.


The view from the top