PETRONAS TWIN TOWER , kuala lumpur

The Petronas Twin Towers (also known as the Petronas Towers or just Twin Towers), in Kuala Lumpur, Malaysia are twin towers and were the world's tallest buildings, before being surpassed by Taipei 101. However, the towers are still the tallest twin buildings in the world. They were the world's tallest buildings from 1998 to 2004 if measured from the level of the main entrance to the structural top, the original height reference used by the US-based Council on Tall Buildings and Urban Habitat from 1969 (three additional height categories were introduced as the tower neared completion in 1996).[2]

In accordance to CTBUH, the pinnacles contributed to the overall height of the towers, thus surpassing the Sears Tower.

The Petronas Twin Towers were the tallest buildings in the world until Taipei 101, as measured to the top of their structural components (spires, but not antennas), took over the record. Spires are considered integral parts of the architectural design of buildings, to which changes would substantially change the appearance and design of the building, whereas antennas may be added or removed without such consequences. The Petronas Twin Towers remain the tallest twin buildings in the world.

The Sears Tower and the World Trade Center towers were each constructed with 110 occupied floors – 22 more than the Petronas Twin Towers’ 88 floors. The Sears Tower and the World Trade Center’s roofs and highest occupied floors substantially exceeded the height of the roof and highest floors of the Petronas Twin Towers. The Sears Tower’s tallest antenna is 75 m (246 ft) taller than the Petronas Twin Towers’ spires. However, in accordance to CTBUH regulations and guidelines,

[2] the antennas of the Sears Tower were not counted as part of its architectural features.

[3]Therefore, the Petronas Twin Towers exceed the official height of the Sears Tower by 10m, but the Sears Tower has more floors with occupied office space at a higher level.

History

Designed by Argentine-American architect César Pelli, the Petronas Towers were completed in 1998 and became the tallest buildings in the world on the date of completion. They were built on the site of Kuala Lumpur's race track. Because of the depth of the bedrock, the buildings were built on the world's deepest foundations. The 120-meter foundations were built by Bachy Soletanche, and required massive amounts of concrete.

The 88-floor towers are constructed largely of reinforced concrete, with a steel and glass facade designed to resemble motifs found in Islamic art, a reflection of Malaysia's Muslim religion. Another Islamic influence on the design is that the cross-section of the towers is based on a Rub el Hizb (albeit with circular sectors added to meet office space requirements).

Due to a lack of steel and the huge cost of importing steel, the towers were constructed on a cheaper radical design of super high-strength reinforced concrete. High-strength concrete is a material familiar to Asian contractors and twice as effective as steel in sway reduction; however, it makes the building twice as heavy on its foundation than a comparable steel building. Supported by 23-by-23 meter concrete cores and an outer ring of widely-spaced super columns, the towers use a sophisticated structural system that accommodates its slender profile and provides from 1300 to 2000 square metres of column-free office space per floor.Below the twin towers is Suria KLCC, a shopping mall, and Dewan Filharmonik Petronas, the home of the Malaysian Philharmonic Orchestra.

Other buildings have used spires to increase their height but have always been taller overall to the pinnacle when trying to claim the title. In the aftermath of the controversy, the rules governing official titles were partially overhauled, and a number of buildings re-classified structural antenna as architectural details to boost their height rating (even though nothing was actually done to the building).

Tenants of the Petronas Twin Towers
A skybridge connects the two towers


Tower One is fully occupied by the Petronas Company and a number of its subsidiaries and associate companies. The office spaces in Tower Two are mostly available for lease to other companies. A number of companies have offices in Tower Two, including Accenture, Al Jazeera English, Carigali Hess Bloomberg, Boeing, IBM, Khazanah Nasional Berhad, McKinsey & Co, TCS, Krawler Networks, Microsoft, The Agency(A modeling company) and Reuters.



Spanning 17 acres (69,000 m2) below the building is the KLCC park with jogging and walking paths, a fountain with incorporated light show, wading pools, and a children's playground. Suria KLCC is one of the largest shopping malls in Malaysia.



The towers feature a skybridge (constructed by Kukdong Engineering & Construction of South Korea) between the two towers on 41st and 42nd floors, which is the highest 2-story bridge in the world. The bridge is 170m above the ground and 58 m long, weighing 750 tons. The same floor is also known as the podium, since visitors desiring to go to higher levels have to change elevators here. The skybridge is open to all visitors, but free passes (limited to 1700 people per day) must be obtained on a first-come, first-served basis. Visitors are only allowed on the 41st floor as the 42nd floor can only be used by the tenants of the building.

The skybridge also acts as a safety device, so that in the event of a fire or other emergency in one tower, tenants can evacuate by crossing the skybridge to the other tower. The total evacuation triggered by a bomb hoax on 12 September 2001 [4] (the day after the September 11 attacks destroyed the Twin Towers of the World Trade Center in New York City) showed that the bridge would not be useful if both towers need to be emptied simultaneously, as the capacity of the staircases was insufficient for such an event. Plans thus call for the lifts to be used if both towers need to be evacuated, and a successful drill following the revised plan was conducted in 2005.

The Lift System

The main bank of Otis lifts is located in the centre of each tower. All main lifts are double-decker with the lower deck of the lift taking passengers to odd numbered floors and upper deck to even numbered floors. In order to access an even numbered floor from ground level, passengers are required to use an escalator to access the upper deck of the elevator.

From the ground floor, there are three groups of lifts. The "short haul" group of 6 lifts take passengers to floors between level 2/3 and level 16/17. The "mid haul" group of 6 lifts take passengers to floors between level 18/19 and level 37/38. There is also a set of shuttle lifts that take passengers directly to levels 41/42. In order to get to levels above 41/42, passengers are required to take the shuttle lifts and then change lifts to the upper floors. These connecting lifts are placed directly above the lifts serving levels 2 to 38. The pattern now repeats with the upper levels, one set serving =levels 43/44 to 57/58 and one set serving levels 59/60 to levels 73/74.

Apart from this main bank of lifts, there are a series of "connecting" lifts to take people between the groups. Unlike the main lifts, these are not the double-decker type. Two lifts are provided to take people from levels 37/38 to levels 41/42 (levels 39 and 40 are not accessible as office space). This avoids the need for someone situated at the lower half of the building to go down to the ground floor in order to gain access to the upper half of the building.

The lifts contain a number of safety features. It is possible to evacuate people from a lift stuck between floors by manually driving one of the adjacent lifts next to it and opening a panel in the wall. It is then possible for people in the stuck lift to walk between elevator cars.

During an evacuation of the buildings, only the shuttle lift is allowed to be used. This is because there are only doors at levels G/1 and levels 41/42 therefore should there be a fire in the lower half of the building, this enclosed shaft would remain unaffected.

Service building

The service building is to the east of the Petronas Towers and contains the services required to keep the building operational, such as dissipating the heat from the air-conditioning system for all 88 levels in both towers.

Notable events

Thousands of people were evacuated on September 12 2001 after a bomb threat were phoned in the day after the September 11 attacks destroyed the Twin Towers of the World Trade Center in New York City. Bomb squads found no explosives in the Petronas towers, and workers and shoppers were allowed to return three hours later, around noon. No one was hurt, but six people fainted during the evacuation.[5]

On the evening of Friday, November 4, 2005, a fire broke out in the cinema complex of the Suria KLCC shopping centre below the Petronas Twin Towers, triggering panic among patrons who fled screaming and coughing in the thick, acrid smoke. There were no reports of injuries. The buildings were largely empty (except the shopping mall, Suria KLCC) because of the late hour; the only people affected were moviegoers and some diners in restaurants.[6]

On March 20, 1997, French urban climber, Alain "Spiderman" Robert, using only his bare hands and feet and with no safety devices, scaled the building's exterior glass and steel wall. Police arrested him at the 60th floor, 28 floors away from the "summit." He made a second attempt on March 20, 2007, exactly 10 years later, and was stopped once again on the same floor (though on the other tower).[7]

Popular culture

The Petronas Towers were a setting for some scenes in the 1999 film Entrapment starring Sean Connery and Catherine Zeta-Jones. It ends in a dramatic pursuit of the two stars by Pasukan Gerakan Khas as SWAT teams, eventually leading to Connery's capture and Zeta-Jones's escape. The towers also feature in three levels of the game Hitman 2: Silent Assassin where the player travels from one tower to another using the sky bridge, though it is unlike the real sky bridge; instead of being a narrow passageway, the sky bridge is wide and entered by breaking a panel of glass. The PS2 game Burnout Dominator features the Twin Towers as Spiritual Towers. Episode 22 from the anime series Cowboy Bebop shows what closely resembles the Petronas Twin Towers being blown up by a terrorist. This episode was taken off the air for a short time post-9/11. The Petronas Towers are also a major setting in the 2006 Bollywood film, Don - The Chase Begins Again, starring Shah Rukh Khan.