Editing Petronas Towers (section)

==History and architecture==
The Petronas Towers' [[structural system]] is a [[Tube (structure)|tube in tube design]], invented by Bangladeshi-American architect [[Fazlur Rahman Khan]].<ref>{{Cite magazine |date=2010 |title=Tall Buildings in Numbers |url=http://www.ctbuh.org/LinkClick.aspx?fileticket=rlKQFdZyhwg%3D&tabid=1108&language=en-GB |magazine=CTBUH Journal |volume=2010 |issue=2 |pages=40–41 |access-date=13 January 2015 |archive-date=24 July 2018 |archive-url=https://web.archive.org/web/20180724154150/http://www.ctbuh.org/LinkClick.aspx?fileticket=rlKQFdZyhwg%3D&tabid=1108&language=en-GB |url-status=dead }}</ref><ref>{{Cite book |url=https://books.google.com/books?id=K792dXxSI4UC&q=tube+in+tube+petronas+tower&pg=PA24 |title=Structures in the New Millennium: Proceedings of the Fourth International Kerensky Conference on Structures in the New Millennium, Hong Kong, 3–5 September 1997 |date=1997 |publisher=A. A. Balkema |isbn=90-5410-898-3 |editor-last=Lee |editor-first=P. K. K. |location=Rotterdam}}</ref> Applying a tube-structure for extreme tall buildings is a common phenomenon.<ref>{{Cite web |last=Koppen |first=Paul |title=Pudong and Shanghai World Financial Center |url=http://www.support.tue.nl/archief/studiereizen/studiereis2007/pudong_swf_en.htm |archive-url=https://web.archive.org/web/20140714182328/http://www.support.tue.nl/archief/studiereizen/studiereis2007/pudong_swf_en.htm |archive-date=14 July 2014 |access-date=18 June 2014 |website=support.tue.nl }}</ref><ref>{{Cite web |title=Know About |url=https://www.constructingworld.com/single-post/2016/08/29Know-about-Petronas-Towers |archive-url=https://web.archive.org/web/20180724154154/https://www.constructingworld.com/single-post/2016/08/29Know-about-Petronas-Towers |archive-date=24 July 2018 |website=ConstructingWorld}}</ref>
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.<ref>{{Cite book |title=Local Cultures and the "New Asia": The State, Culture, and Capitalism in Southeast Asia |date=2002 |publisher=Institute of Southeast Asian Studies |editor-last=Wee |editor-first=C. J. Wan-Ling |location=Singapore |page=193}}</ref> Another Islamic influence on the design is that the [[Cross section (geometry)|cross section]] of the towers is based on a [[Rub el Hizb]], albeit with circular sectors added to meet office space requirements.<ref>{{Cite book |last=Moskal |first=Greg |url=https://archive.org/details/modernbuildingsi0000mosk/page/28 |title=Modern Buildings: Identifying Bilateral and Rotational Symmetry |publisher=Rosen Classroom |date=2004 |isbn=0-8239-8989-5 |location=New York |page=[https://archive.org/details/modernbuildingsi0000mosk/page/28 28]}}</ref> The circular sectors are similar to the bottom part of the [[Qutb Minar]].

[[File:Petronas Towers level 43 plan.svg|thumb|150px|Development of the Petronas Towers Tower 1 level 43 floor plan from a [[Rub el Hizb]] symbol.
<ref>{{Cite web |author=Galal Abada |date=2004 |title=Petronas Office Towers |url=http://www.akdn.org/architecture/pdf/1969_Mal.pdf |url-status=unfit |archive-url=https://web.archive.org/web/20121001183326/http://www.akdn.org/architecture/pdf/1969_Mal.pdf |archive-date=1 October 2012 |location=Kuala Lumpur, Malaysia}}</ref>]]

[[File:Qutub Minar danibaba5.jpg|thumb|150px|The cross section of the Petronas Towers is based on a ''[[Rub el Hizb]]'', albeit with circular sectors similar to the bottom part of the [[Qutb Minar]]. ]]
[[File:Petronas Panorama II (4to3).jpg|thumb|200x200px|The Petronas Towers at night, 2008]]
The towers were designed by [[Argentine Americans|Argentine-American]] architect [[César Pelli]]. A distinctive [[Postmodern architecture|postmodern]] style was chosen to create a 21st-century icon for Kuala Lumpur, Malaysia. Planning on the Petronas Towers started on 1 January 1992 and included rigorous tests and simulations of wind and structural loads on the design. Seven years of construction followed at the former site of the original [[Selangor Turf Club]], beginning on 1 March 1993 with excavation, which involved moving 500 truckloads of earth every night to dig down {{Convert|30|m}} below the surface.
The construction of the superstructure commenced on 1 April 1994. Interiors with furniture were completed on 1 January 1996, the spires of Tower 1 and Tower 2 were completed on 1 March 1996, 3 years after its construction was started, and the first batch of [[Petronas]] personnel moved into the building on 1 January 1997. The building was officially opened by the [[Prime Minister of Malaysia]], [[Mahathir Mohamad|Tun Dr. Mahathir bin Mohamad]], on 31 August 1999.<ref>{{Cite book |last=Sebestyén |first=Gyula |title=Construction: Craft to Industry |date=1998 |publisher=Taylor & Francis |isbn=978-0-419-20920-1 |location=London |page=205}}</ref> The twin towers were built on the site of Kuala Lumpur's race track. It was the tallest structure in [[Malaysia]] at the time of its completion.<ref>{{Cite book |last1=Žaknić |first1=Ivan |title=100 of the World's Tallest Buildings |author2=Smith, Matthew |author3=Rice, Doleres B. |date=1998 |publisher=Images Publishing |isbn=978-1-875498-32-1 |location=Mulgrave, Victoria |page=208}}</ref> Test boreholes found that the original construction site effectively sat on the edge of a cliff. One half of the site was decayed limestone while the other half was soft rock. The entire site was moved {{convert|61|m|ft}} to allow the buildings to sit entirely on the soft rock.<ref name="Anstey">National Geographic Channel International / Caroline Anstey (2005), ''Megastructures: Petronas Twin Towers''</ref> Because of the depth of the [[bedrock]], the buildings were built on the world's deepest foundations.<ref>{{Cite journal |last1=Baker |first1=Clyde N. Jr. |last2=Drumwright |first2=Elliott |last3=Joseph |first3=Leonard |author4=Tarique Azam |date=November 1996 |title=The Taller the Deeper |journal=Civil Engineering |publisher=ASCE |volume=66 |issue=11 |pages=3A–6A}}</ref> 104 concrete piles, ranging from {{Convert|60|to|114|m}} deep, were bored into the ground. The concrete raft foundation, comprising {{Convert|13200|m3}} of concrete was continuously poured through a period of 54 hours for each tower. The raft is {{convert|4.6|m|ft}} thick, weighs {{Convert|32500|tonne}} and held the world record for the largest concrete pour until 2007.<ref name="Anstey"/> The foundations were completed within 12 months by Bachy Soletanche and required massive amounts of concrete.<ref>{{Cite web |date=18 March 2010 |title=Detailed Structural Analysis |url=http://www.thepetronastowers.com/2010/03/petronas-towers-%E2%80%93-detailed-structural-analysis/ |archive-url=https://web.archive.org/web/20101101221729/http://www.thepetronastowers.com/2010/03/petronas-towers-%E2%80%93-detailed-structural-analysis/ |archive-date=1 November 2010 |access-date=11 January 2011 |website=The Petronas Towers }}</ref>
 
As a result of the Malaysian government specifying that the buildings be completed in six years, two construction consortia were hired to meet the deadline, one for each tower. Tower 1, the west tower (left in the top-right photograph) was built by a Japanese consortium led by the [[Hazama Corporation]] ([[J.A. Jones Construction|JA Jones Construction Co.]], MMC Engineering Services Sdn Bhd, Ho Hup Construction Co. Bhd and [[Mitsubishi Corporation|Mitsubishi Corp]]) while Tower 2, the east tower (right in the top-right photograph) was built by a South Korean consortium led by the [[Samsung C&T Corporation]] (Kukdong Engineering & Construction and Syarikat Jasatera Sdn Bhd).

Early into construction a batch of concrete failed a routine strength test causing construction to come to a complete halt. All the completed floors were tested but it was found that only one had used a bad batch and it was demolished. As a result of the concrete failure, each new batch was tested before being poured. The halt in construction had cost US$700,000 per day and led to three separate [[concrete plant]]s being set up on the site to ensure that if one produced a bad batch, the other two could continue to supply concrete. The sky bridge contract was completed by Kukdong Engineering & Construction. Tower 2 (Samsung C&T) became the first to reach the world's tallest building at the time.

Due to the huge cost of importing steel, the towers were constructed on a cheaper radical design of super high-strength reinforced concrete.<ref>{{Cite book |last=Wells |first=Matthew |title=Skyscrapers: Structure and Design |date=2005 |publisher=Laurence King Publishing |location=London |page=170}}</ref> 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 as a comparable steel building. Supported by 23-by-23 metre concrete cores<ref>"Information Malaysia." (2005). Berita Publ. Sdn. Bhd.</ref> 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.<ref>{{Cite book |last=Taranath |first=Bungale S. |title=Wind and Earthquake Resistant Buildings: Structural Analysis and Design |date=2004 |publisher=CRC Press |page=748}}</ref> Below the twin towers is [[Suria KLCC]], a shopping mall, and [[Petronas Philharmonic Hall]], the home of the [[Malaysian Philharmonic Orchestra]].

===Notable events===

* On 15 April 1999, [[Felix Baumgartner]] set the world record for [[BASE jumping]] (since broken) by jumping off a window cleaning crane on the Petronas Towers.<ref>{{Cite web |last=Crerar |first=Simon |date=15 October 2012 |title=Planes, Caves and Skyscrapers Among Fearless Skydiver Felix Baumgartner's Fabulous Feats |url=https://www.perthnow.com.au/news/nsw/planes-caves-and-skyscrapers-among-fearless-skydiver-felix-baumgartners-fabulous-feats-ng-b468ebc985a31f2b3d44b9fd6a3b1de2 |access-date=16 February 2022 |website=PerthNow}}</ref><ref>{{Cite web |title=Petronas Towers (451 Meters), Malaysia |url=http://www2.felixbaumgartner.com/index.php?id=54&tx_ttnews%5bpS%5d=915145200&tx_ttnews%5bpL%5d=31535999&tx_ttnews%5barc%5d=1&tx_ttnews%5btt_news%5d=48&tx_ttnews%5bbackPid%5d=33&cHash=7c1597d667 |archive-url=https://web.archive.org/web/20100922072134/http://felixbaumgartner.com/index.php?id=54&tx_ttnews[pS]=915145200&tx_ttnews[pL]=31535999&tx_ttnews[arc]=1&tx_ttnews[tt_news]=48&tx_ttnews[backPid]=33&cHash=7c1597d667 |archive-date=22 September 2010 |access-date=21 October 2012 |website=felixbaumgartner.com |publisher=Felix Baumgartner }}</ref>
* Thousands of people were evacuated on 12 September 2001 after a bomb threat the day after the [[September 11 attacks]] destroyed the [[World Trade Center (1973–2001)|World Trade Center]] towers in New York City. Bomb disposal squads found no explosives in the towers, but they nevertheless evacuated the premises. Workers and shoppers were allowed to return three hours later, around noon. No one was hurt during the evacuation.<ref>{{Cite news |last=Yoong |first=Sean |date=12 September 2001 |title=World's Tallest Towers, IBM Building in Malaysia Evacuated After Threats |work=Lubbock Online: The Avalanche Journal |agency=Associated Press |url=http://www.avalanchejournal.com/stories/091201/upd_worldevacs.shtml |access-date=11 January 2011 |archive-url=https://archive.today/20120719154930/http://www.avalanchejournal.com/stories/091201/upd_worldevacs.shtml |archive-date=19 July 2012}}</ref>
* On the evening of 4 November 2005, a fire broke out in the [[Tanjong Golden Village|cinema complex]] of the Suria KLCC shopping centre below the Petronas Towers, triggering panic among patrons. 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.<ref>{{Cite news |date=4 November 2005 |title=Fire Forces Evacuation at Malaysia Towers |work=CBS News |url=https://www.cbsnews.com/stories/2005/11/04/ap/world/mainD8DLSFK00.shtml |access-date=11 January 2011 |archive-url=https://web.archive.org/web/20081207081700/http://www.cbsnews.com/stories/2005/11/04/ap/world/mainD8DLSFK00.shtml |archive-date=7 December 2008}}</ref>
* On the morning of 1 September 2009, French urban climber [[Alain Robert|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.<ref>{{Cite news |date=1 September 2009 |title='Spiderman' Scales Malaysia Tower |work=BBC News |url=http://news.bbc.co.uk/2/hi/asia-pacific/8231076.stm |access-date=11 January 2011}}</ref> In his first attempt on 20 March 1997, police arrested him at the 60th floor, 28 floors away from the "summit". His second attempt, on 20 March 2007, exactly 10 years later, was also stopped on the same floor, though on the other tower.<ref>{{Cite news |date=20 March 2007 |title='Spiderman' Has Another Go at Twin Tower |work=The Star Online |url=http://thestar.com.my/news/story.asp?file=/2007/3/21/nation/17205712&sec=nation |access-date=11 January 2011 |archive-url=https://web.archive.org/web/20110622031327/http://thestar.com.my/news/story.asp?file=%2F2007%2F3%2F21%2Fnation%2F17205712&sec=nation |archive-date=22 June 2011 }}</ref>