Sky Tower

From Wikipedia, the free encyclopedia

The Sky Tower is an observation- and telecommunications tower located on the corner of Victoria and Federal Streets in the central business district of Auckland, New Zealand. It is 328 metres tall, as measured from ground level to the top of the mast,^[1] making it the tallest free-standing structure in the Southern Hemisphere, and the 12th tallest member of the World Federation of Great Towers.^[2] It is an iconic Auckland structure, often used in logos and promotions.

The landmark is part of the SKYCITY Auckland casino complex, owned and operated by SKYCITY Entertainment Group.

[edit] Uses

The upper portion of the tower contains two restaurant levels (one, the 'Orbit' with revolving seating, turning 360 degrees once every hour)^[3] and one cafe level, as well as two observation decks (including some with sections of glass floor).^[3] The tower attracts over 600,000 visitors a year.^{[citation needed]}

The tower also features the SkyJump, a 192-metre^[4] 'fan descender' jump (an experience between a bungy jump and a base jump) from the observation deck, during which a jumper can reach up to 85 km/h. The jump is guide-cable-controlled to prevent jumpers from colliding with the tower in case of gusts.^[5] Climbs into the antennae portion (300 m heights) are also possible for tour groups.^[4]

As well as for entertainment, the tower is used for telecommunications and broadcasting with the Auckland Peering Exchange (APE) being located on Level 48. Several radio broadcasting companies co-locate transmitters and share antenna systems, while television company Canwest (who runs the TV3 and C4 channels) has secondary transmitters on the tower, their primary one being at Waiatarua.^{[citation needed]}

[edit] Construction

[edit] Project history

Fletcher Construction was the contracted builder for the project^[6][1] while engineering firm Beca Group provided the design management and coordination, structural,^[1] geotechnical, civil, mechanical, electrical, plumbing, lighting and fire engineering services. It was designed by Gordon Moller of Craig Craig Moller, and has received a New Zealand Institute of Architects National Award as well as regional awards.^[7]

Taking two and a half years of construction time, the tower was opened on March 3, 1997, six months ahead of schedule.^[8]

[edit] Facts & Figures

The tower is constructed of reinforced, high-performance concrete. Its 12 metre diameter shaft (containing three lifts and an emergency stairwell) is supported on eight 'legs' based on 16 foundation piles drilled over 12 m deep into the local sandstone.^[6][1] The main shaft was built using climbing formwork.^[1]

The upper levels were constructed from composite materials, structural steel, precast concrete and reinforced concrete,^[1] and the observation decks clad in aluminium with blue/green reflective glass. A structural steel framework supports the upper mast structure. During construction 15,000 cubic metres of concrete, 2,000 tonnes of reinforcing steel and 660 tonnes of structural steel were used. The mast alone weighs over 170 tonnes.^[1][9] It had to be lifted into place using a crane attached to the structure, as it would have been too heavy for a helicopter to lift. To then remove said crane, another crane had to be constructed attached to the upper part of the Sky Tower structure, which dismantled the big crane, and was in turn dismantled into pieces small enough to fit into the elevator.^[1]

[edit] Emergencies

The tower is designed to withstand wind in excess of 200 km/h and resist earthquakes with a 1,000 year return period. Analysis shows that an earthquake centered 40 kilometers away and reaching 7.0 on the Richter magnitude scale is expected to leave the tower practically undamaged. Even an earthquake measured at a magnitude of 8.0 (10 times stronger than a 7.0 quake), and located only 20 km away, is not expected to collapse the tower.^[1] As an additional safeguard against emergencies, fireproof rooms on the lower levels of the observation deck would provide refuge in the unlikely event of a conflagration, while the stairwell itself is also fire-safety rated.^[9]

The sky tower has so far been closed once for weather-related reasons, during a storm in November 2006, when the structure started to sway noticably in winds of up to 150 km/h. The closure was noted as not having been strictly necessary except for visitor comfort, as the tower has been designed to sway up to one meter^[10] in high winds of up to 210 km/h, which are expected to occur only once in 1,000 years on average.^[1]

[edit] References

1. ^ ^{a b c d e f g h i j} Case Studies: Sky Tower (from the University of Auckland, Department of Civil & Environmental Engineering. Retrieved 2007-12-01.)
2. ^ Fun Facts (from the SKYCITY Auckland website. Retrieved 2007-10-22.)
3. ^ ^{a b} Orbit, Sky Tower - The New Zealand Herald, Saturday 19 May 2007
4. ^ ^{a b} Auckland: Don't Miss: Action in the outdoors (from the Tourism New Zealand website. Retrieved 2007-12-02.)
5. ^ SkyJump (from the official skyjump.co.nz website)
6. ^ ^{a b} Projects: Commercial: Sky Tower (from the Fletcher Construction website. Retrieved 2007-12-02.)
7. ^ Sky Tower (from the website of Craig Craig Moller, Sky Tower's architects)
8. ^ Sky Tower (from 'Feature Projects', Beca Group website)
9. ^ ^{a b} Construction Facts (from the SKYCITY Auckland website)
10. ^ Some homes still powerless after storm - The New Zealand Herald, Friday 10 November 10, 2006

[edit] See also

• Macau Tower (inspired by the Sky Tower, designed by the same company)
• SkyCity Auckland (base building of the Sky Tower complex)
• Sydney Tower (The second tallest observation tower in the Southern Hemisphere)

[edit] External links

• Sky Tower (official Sky Tower website)
• Sky Tower in the Structurae database
• Explore the Sky Tower (interactive Sky Tower, requires Macromedia Flash)

• 360° view from tower (from Skycity website, requires Quicktime)

• Sky Tower is at coordinates 36°50′55″S 174°45′44″E / -36.848461, 174.762183Coordinates: 36°50′55″S 174°45′44″E / -36.848461, 174.762183

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