Petronas Towers

 The Petronas Towers (also known as the Petronas Twin Towers or, rather incorrectly, KLCC) are skyscrapers and twin towers in Kuala Lumpur, Malaysia. They were the tallest buildings in the world from 1998 to 2004 until surpassed by Taipei 101, but remain the tallest twin buildings in the world.The building is the landmark of Kuala Lumpur with nearby Kuala Lumpur Tower.

Comparison with other towers                                                         

The Petronas Towers were the tallest buildings in the world for six years, until Taipei 101 was completed in 2004. The height of the towers is measured to the top of their structural components such as spires, but do not include antennas. Spires are considered actual 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 Towers still remain the tallest twin buildings in the world.

The Petronas's height compared to some other well-known tall structures

Willis Tower (formerly Sears Tower) and the World Trade Center towers were each constructed with 110 occupied floors – 22 more than the 88 floors of the Petronas Towers. Willis Tower’s tallest antenna is 247.4 ft taller than those of the Petronas Towers, however, in accordance to CTBUH regulations and guidelines,the antennas of Willis Tower were not counted as part of its architectural features.The spires on the Petronas Towers are included in the height since they are not antenna masts. Therefore, the Petronas Towers exceed the official height of Willis Tower by 10 m.

History

Designed by Argentine architects Cesar Pelli and Djay Cerico under the consultancy of Julius Gold and Filipino engineer Domingo Basa, the Petronas Towers were completed in 1998 after a seven year build 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 racetra Because of the depth of the bedrock, the buildings were built on the world's deepest foundations. The 120-meter foundations were built within 12 months by Bachy Soletanche and required massive amounts of concrete. Its engineering designs on structural framework were contributed by Haitian engineer Domo Obiasse and colleagues Aris Battista and Princess D Battista.
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.Tower 1 was built by a Japanese consortium led by the Hazama Corporation while Tower 2 was built by Samsung C&T and Kukdong Engineering & Construction, both South Korean contractors.The sky bridge contract was completed by Kukdong Engineering & Construction. Thus, Tower 2 became the first to reach the world's tallest building at the time.
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 metre 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 560,000 square metres of column-free office space.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.



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

Suria KLCC

Suria KLCC is a 1,500,000 sq ft (139,000 m²) upmarket retail podium at the feet of the Petronas Towers. It features mostly foreign luxury goods and high-street labels. Its attractions include an art gallery, a philharmonic theater, an underwater aquarium and also a Science centre.

                                                    

                                                   
KLCC park

Spanning 17 acres (6.9 ha) 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.

Skybridge

The towers feature a skybridge  between the two towers on 41st and 42nd floors, which is the highest 2-story bridge in the world.It is not attached to the main structure, but is instead designed to slide in and out of the towers to prevent it from breaking during high winds.The bridge is 170 m (558 ft) above the ground and 58 m (190 ft) 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 tickets are limited to 1700 people per day, and must be obtained for free 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 September 12, 2001 (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.

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. To reach an even-numbered floor from ground level, passengers must take an escalator  to the upper deck of the lift.
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 six 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. To get to levels above 41/42, passengers must take the shuttle lifts, then change to lifts to the upper floors. These connecting lifts are directly above the lifts that serve 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 spares someone in the lower half of the building from having to go back to the ground floor to go 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 lift cars.During an evacuation of the buildings, only the shuttle lift is allowed to be used, as 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. Firefighter lifts are also provided in case of emergency.

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 12 September 2001 after a bomb threat was phoned in the day after the attacks destroyed the twin towers of the World Trade Center in New York City. Bomb Disposal squads found no bomb in the Petronas towers but they evacuated everyone. Workers and shoppers were allowed to return three hours later, around noon. No one was hurt during the evacuation.
On the evening of 4th November, 2005, a fire broke out in the cinema complex of the Suria KLCC shopping centre below the Petronas Towers, triggering panic among patrons who joined screaming 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 involved were moviegoers and some diners in restaurants.
On the morning of 1 September 2009, French urban climber, Alain “Spiderman” Robert, using only his bare hands and feet and with no safety devices, scaled to the top of Tower Two in just under 2 hours after two previous efforts had ended in arrest. On 20th March, 1997, police arrested him at the 60th floor, 28 floors away from the "summit." He made a second attempt on 20 March 2007, exactly 10 years later, and was stopped once again on the same floor, though on the other tower.
The climax of the 1999 film Entrapment was filmed at the skybridge.