Petronas Towers

The Petronas Towers (Malay: Menara Petronas, also known as the Petronas Twin Towers or Menara Berkembar Petronas in Malay) are twin skyscrapers in Kuala Lumpur, Malaysia. According to the CTBUH's official definition and ranking, they were the tallest buildings in the world from 1998 to 2004 until surpassed by Taipei 101, but remain the tallest twin buildings ever built, surpassing the World Trade Center.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 Towers and the Kuala Lumpur Tower dominate the skyline of Kuala Lumpur's Central Business District.
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 75.41 m (247.4 ft) taller than those of the Petronas Towers, however, in accordance with 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 (33 ft) even though the roof of Petronas Towers (378.6 m) is 63.4 m (208 ft) lower than the roof of Willis Tower (442 m).

History

Designed by Argentine architect César Pelli and Filipino-Malaysian Engineer Deejay Cerico under the consultancy of J. C. Guinto, and Filipino Designer Dominic "Minick" Saibo, the Petronas Towers were completed in 1998 after seven years of construction and became the tallest buildings in the world.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 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, the west tower (right in the top-right photograph) was built by a Japanese consortium led by the Hazama Corporation while Tower 2, the east tower (left in the top-right photograph) was built by Samsung C&T Corporation and Kukdong Engineering & Construction, both South Korean contractors.[citation needed] The sky bridge contract was completed by Kukdong Engineering & Construction. Tower 2 became the first to reach the world's tallest building at the time. However, the builders of Tower 2, Samsung Constructions, ran into problems when they discovered the structure was leaning 25 millimeters off from vertical.

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.[18] 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.

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,[24] as the towers sway several feet[specify] in towards and away from each other during high winds. It also provides some structural support to the towers in these occasions. 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 about 1000 people per day, and must be obtained on a first-come, first-served basis. Initially, the visit was free but in 2010, the tickets started being sold by Petronas. Visitors can choose to opt for package one which is just a visit to the skybridge or go for package two to go to the skybridge and all the way to level 86.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.