CTBUH Technical Paper

http://technicalpapers.ctbuh.org

Subject: Other

Paper Title: Talking Tall: The Global Impact of 9/11

Author(s): Klerks, J.

Affiliation(s): CTBUH

Publication Date: 2011

Original Publication: CTBUH Journal 2011 Issue III

Paper Type: 1. Book chapter/Part chapter 2. Journal paper 3. Conference proceeding 4. Unpublished conference paper 5. Magazine article 6. Unpublished

Tall buildings: design, construction and operation | 2011 Issue III

Special Edition World Trade Center: Ten Years On Inside

Case Study: One World Trade Center, New York News and Events 36 Challenging Attitudes on 14 “While, in an era of supertall buildings, big of new development. The new World Trade Bridging over the tracks was certainly an Center Transportation Hub alone will occupy engineering challenge. “We used state-of-the- numbers are the norm, the numbers at One 74,300 square meters (800,000 square feet) to art methods of analysis in order to design one Codes and Safety serve 250,000 pedestrians every day. Broad of the primary shear walls that extends all the World Trade are truly staggering. But the real concourses (see Figure 2) will connect Tower way up the tower and is being transferred at One to the hub’s PATH services, 12 subway its base to clear the PATH train lines that are 02 This Issue story of One World Trade Center is the lines, the new Fulton Street Transit Center, the crossing it,” explains Yoram Eilon, vice Kenneth Lewis Nicholas Holt World Financial Center and Winter Garden, a president at WSP Cantor Seinuk, the structural innovative solutions sought for the ferry terminal, underground parking, and retail engineers for the project. “In addition, the Jose Torero Authors unprecedented challenges faced in building a and dining venues. layout of below grade structure and columns Kenneth Lewis, Managing Director took into account the dynamic envelope of Nicholas Holt, Technical Director The resulting underground challenges can be Charles Killebrew, Figure 2. Councourse below grade © SOM these train lines. The design of the structure project of this size on such a difficult site.” likened to a four-dimensional chess game. Skidmore, Owings & Merrill LLP But the real story of One World Trade Center is also meets the Port Authority requirements 14 Wall Street First of all, obstructions exist three the innovative solutions sought for the that these lines remain operable during New York, NY 10005 The world knows what happened in Lower Manhattan on September 11, 2001. The twin dimensionally in overlapping planes at unprecedented challenges faced in building a construction. In order to comply, we designed t: +1 212 298 9300 towers of the World Trade Center and several other buildings were damaged or destroyed, varying depths. Secondly, per the brief, the f: +1 212 298 9500 project of this size on such a difficult site. a steel structure that bridges over the tracks, CTBUH Trustee e: [email protected] and more than 3,000 people were killed. The ground smoldered for months. Rescue was PATH train service was to remain operational which supported the wet concrete loads www.som.com replaced by recovery, which was followed by eight brutal months of removing thousands of and existing structures had to be preserved during construction and was eventually tons of debris from what became known as Ground Zero. What most people do not realize is throughout excavation and construction. Site integrated into the permanent structure.” 38 How WTC Affected Tall Kenneth Lewis that reconstruction of the 6.5-hectare (16-acre) site began soon after the cleanup, due to the Threading steel members, conduits, and Kenneth A. Lewis is a Director in SOM’s New York office. The project team was confronted with He joined the firm in 1986 and has served on a diverse fact that the initial work began underground and was therefore out of sight. shafts through the maze required precision range of projects including mixed-use developments, unprecedented challenges. The site sits over a timing not only to avoid service or commercial towers, corporate headquarters, and Now that buildings are emerging into the 10th anniversary of the attacks in September vast tangle of existing subterranean obstacles. Structural Design healthcare facilities. construction disruptions, but to ensure that light of day, the ambitious redevelopment is 2011. The Port Authority is developing a major The new tower must bridge existing PATH The tower’s structure is designed around a Mr. Lewis began his career at SOM as Senior Designer. subsequent development would not be Building Life Safety Design He has managed and brought to successful clearly visible. One World Trade Center (1WTC), transportation hub. Silverstein Properties, the train tracks adjacent to existing subway tracks, obstructed. massive, redundant steel moment frame completion several projects of enormous scale, designed by Skidmore, Owings & Merrill, is previous developer of 1WTC, is building three as well as accommodate a planned network consisting of beams and columns ® complexity, and visibility, including the award-winning 04 CTBUH News and Events mixed-use Time Warner Center at Columbus Circle in rising on the northwest corner of the site. The additional office towers for the site. New York and the 7 World Trade Center in Lower National September 11 Memorial is also under Manhattan, and Brookfield Properties’ Hudson Yards Even with all of these high-profile projects, Competition Entry. He is currently managing the One construction and will be completed by the 1WTC will dominate the site, not merely as World Trade Center. All of the projects Ken is managing Carl Baldasara, Jon Evenson & New York City’s (and North America’s) tallest are slated to achieve a Gold rating under the USGBC LEED® CS rating system. He was also closely involved in building, but as an icon representing the development of sustainability design guidelines Antony Wood, for the World Trade Center. He is active in the public perseverance, innovation, and urban realm, and his projects have been honored with modernism (see Figure 1). The US$ 3.2 billion numerous design awards. tower, based on a revised 2005 design, now Simon Lay Nicholas Holt rises from a footprint measuring 61 by 61 Directing the technical architecture team in SOM’s New York office, Mr. Holt oversees the detailed meters (200 by 200 feet), set back from the CTBUH Executive Director development and documentation for all of the New site’s northwest corner. Constructed of York office’s projects. Since joining SOM in 1995, he has developed extensive experience working on high-rise concrete and steel, the 104-story tower will and supertall commercial/mixed use towers, financial include a multi-level observation deck and trading facilities, health science projects and multi-family residential/hotel towers. reach 417 meters (1,368 feet) above ground. A Mr. Holt is an industry leader in the practical two-story ring supporting broadcasting application of Building Information Modeling (BIM) services will support a spire, which will and the associated implementation of new project delivery models aimed at developing projects more culminate at a symbolic 1,776 feet (541 efficiently and effectively. Recent examples are 250 meters) – 1776 being the year of American 40 An Overview: Urban West 55th Street, and the Mt. Sinai Center for Science and Medicine, which were among the first major independence. projects in NYC to be designed and documented in a 05 Debating Tall 100% BIM environment. While, in an era of supertall buildings, big Mr. Holt also leads the Center for Architecture Science numbers are the norm, the numbers at One and Ecology (CASE), a research collaboration between World Trade are truly staggering: 5,660 cubic SOM and Rensselaer Polytechnic Institute. With a focus Terrorism meters (200,000 cubic feet) of concrete; on developing new sustainable materials and technologies, CASE blends private sector practicality, 92,920 square meters (1 million square feet) of academic exploration and scientific rigor to seek Opinions for and against on a emergent technologies and develop them for practical exterior glazing; 40,800 metric tons (45,000 US application in buildings. tons) of structural steel; and 241,550 square Sofia Dermisi Figure 1. One World Trade Center © SOM/dbox Studio meters (2.6 million square feet) of office space. topical issue 14 | One World Trade Center, New York CTBUH Journal | 2011 Issue III CTBUHCCTCTBTBTBUUHH JJouJoJournalouournarrnnanal | 201120100111111 IssueIIsssuessuueue IIIIIIII OnOOnenene WWoWorldorlrrldldld TradeTTrraadadeddee CeCCenter,ententntteerr,, NNeNewewew YoYYorkorkrk | 1155 42 Impacts on Building Security 05 What’s on the Web? Measures Featuring new content now Geoff Craighead available on the website Revitalizing Lower Manhattan: 20 World Trade Center in Context

Towers Besides One World Trade Center, Towers 2, 3 “It is nearly impossible to predict when the World Trade Center site will and 4 have been planned along the newly 44 Rethinking Evacuation: aligned Greenwich Street, at the eastern be fully rebuilt and occupied. As it is already gradually becoming part of perimeter of the site. Although the 06 CTBUH 2011 Award Winners foundations of Towers 2 and 3 are part of the the New York urban context, it can be argued that there will never be one current ongoing construction, further definitive moment of completion.” development of these buildings has been Rethinking Cities pushed back awaiting market demand. Tower An overview by Jan Klerks, CTBUH Communications Manager/Journal Editor 4, however, is currently under construction. To 2011 Winners of the Best Tall the south of the original site and on the location of the recently demolished Deutsche Almost 10 years after the destruction of the Twin Towers, the reconstruction of the World Trade Center site is in full swing. One World Trade Bank Building, Tower 5 has been planned for Center, which is discussed in the case study paper in this Journal, will be the largest and tallest development on the site, but it is definitely not Antony Wood future development. Located to the north of the only one. In fact, the site will eventually become one of the very few clusters of supertall buildings in the world. As such, it is part of a the World Trade Center site, 7 World Trade development which in significance and importance far exceeds the 65,000 square meters (16 acres) site in Lower Manhattan. The following Center was opened in 2006. All of these Building and Lifetime offers an overview and status update of the components that make up the World Trade Center development. towers are office buildings and no new building has been planned that will carry the Urban Scheme of the then-called Freedom Tower. The plan 10:28 am when the second tower collapsed. number 6 in its name. The master plan for the World Trade Center also contained a number of symbolic An important element in the scheme for the elements, such as a proposed height of 541 The Port Authority of New York and New Achievement Awards site is based on a design by Studio Daniel site is the restoration of the linear Jersey, who was the developer and owner of Figure 3. Tower 2 © Foster + Partners Figure 4. Tower 3, Rogers Stirk Harbour + Partners Libeskind (see Figure 1 and 2). The study was meters (1,776 feet) for the tallest tower thoroughfare of Greenwich, Cortland, Day, © Silverstein Properties (referring to the year in which the Declaration the former World Trade Center, has assumed selected in February 2003 as the master plan and Fulton Streets. As a result, the World Trade responsibility for the development of One Tower 3 at 175 Greenwich Street progress of developing Tower 3 depends on for rebuilding the World Trade Center site. This of Independence was signed) and a concept Center site will be more integrated with its World Trade Center, Tower 5, the National Tower 3 is at the center of the various the ability to finance the project. plan proposed a complex program, which called the “wedge of light.” This concept surrounding area compared to the raised September 11 Memorial & Museum, the buildings around the memorial site (see called for the construction of a memorial with positioned the tower faces in such an plaza concept that was laid on top of 12 transportation hub, and overall site Figure 4). As a result, it stands centrally across Tower 4 at 150 Greenwich Street waterfalls, an underground museum, a visitor arrangement that the faces pointed at the sun demolished city blocks in the former World infrastructure. Towers 2, 3, and 4 are being Greenwich Street from the main axis, formed With a height of 298 meters (977 feet), Tower center, retail space, an intermodal transit hub in the sky at the onset and the end of the Trade Center. attack: 8:46 am when the first plane hit and developed by Silverstein Properties of New by the two reflecting pools of the Memorial. 4 is the lowest projected tower in the site (see Features and five office towers spiraling to the height York City, the lease holder of the 10 million The 71-story tower was designed by Rogers Figure 5 and 6). The building was designed by 08 Global News square foot commercial space of the former Stirk Harbour + Partners and will be 378 the Japanese Pritzker Prize-winning ® World Trade Center. meters (1,240 feet) tall when completed. The 7WTC Tower 2 at 200 Greenwich Street Designed by Foster + Partners, Tower 2 is Highlights from the CTBUH Arts Tower 2 planned to rise to 79 stories. When Center 1WTC constructed, the 411-meter (1,348-foot) tall 50 Talking Tall tower will be the second tallest skyscraper in Transportation Hub & Retail the World Trade Center site and the third Memorial & tallest building in New York City, following global news archive Museum One World Trade Center and the Empire State Tower 3 Building. The sloping roof, consisting of four The Global Impact of 9/11 diamonds inclined toward the memorial (see Figure 3), will provide a visual marker around the skyline of just where the original towers Tower 4 were. Although a completion date has not been projected, foundation work began on June 1, 2010 and should continue until late 2011. Further progress of Tower 2 depends on the demand for office space. Adamson Tower 5 Architects are the executive architects for this Tower as well as Towers 3 and 4. Figure 5. Tower 4, Fumihiko Maki Figure 6. Tower 4 under construction © Jan Klerks 54 Tall Buildings in Numbers Figure 1. World Trade Center Site Plan © SOM Figure 2. World Trade Center Towers © dBoxStudio Case Study © Silverstein Properties New York City Scrapers 20 | Revitalizing Lower Manhattan: World Trade Center in Context CTBUH Journal | 2011 Issue III CTBUH Journal | 2011 Issue III Revitalizing Lower Manhattan: World Trade Center in Context | 21 14 One World Trade Center Kenneth Lewis & Nicholas 56 Design Research Holt Code & Regulations Vertical Architecture STudio 32 Evolution of Building Code Requirements in a Post 9/11 World

“Recommendations from the original Structural 20 Revitalizing Lower Engineering Institute, ASCE and FEMA sponsored report recommended several building code changes. Additional work by Manhattan David Drengenberg Gene Corley NIST and NIBS has resulted in more than 17 Authors David Drengenberg, Engineer code changes.” CTBUH Gene Corley, Senior Vice-President CTLGroup It is not practical to design tall buildings to resist terrorist attacks. However, the terrorist Jan Klerks 5400 Old Orchard Road attacks of September 11, 2001 highlighted several concerns unique to tall buildings subject to Figure 1. Damage to South Face of WTC 2 © NIST Figure 2. Post-Impact Load Redistribution © NIST Skokie, IL 60077 extreme events. Observations resulting from the World Trade Center’s post-attack perfor- t: +1 847 965 7500 f: +1 847 965 6541 mance investigation included: failure of active and passive fire protection systems, impor- 2. Designers should consider fire resistance is provided. Both active and passive systems after major damage, durability of fire systems, e: [email protected] tance of structural redundancy, and performance of egress systems. These observations led to related to member importance. Elements were vulnerable to impact damage. Water and adequate access. Subsequent to the e: [email protected] www.ctlgroup.com recommendations for code modifications. Many recommendations have been incorporated such as transfer girders, truss elements, lines were likely severed, and spray-on publication of their final report, the NIST by the International Code Council into the International Building Code’s 2012 edition. and bracing should have increased fireproofing was stripped away from awarded a contract to the National Institute of

David Drengenberg protection against fire damage protected elements by the initial impact. Building Sciences (NIBS) to convene a panel of 59 CTBUH on the Road David Drengenberg is an engineer in Structural commensurate with the consequences of Without adequate and uninterrupted water building code experts, and begin Attack and Collapse WTC 1 and WTC 2’s ability in particular to Engineering and Mechanics, as well as a member of survive initial impact loads and the resulting failure. supply, sprinkler systems were rendered implementation of the following NIST the Buildings & Facilities Practice Group steering A coordinated terrorist attack launched on committee, at CTLGroup. structural damage is notable. Undoubtedly, ineffectual, and dislodged fireproofing recommendations: September 11, 2001 led to damage and 3. Definitions of credible hazards should be David joined CTLGroup in 2002 with the completion of many hundreds of lives were saved because compromised designed fire ratings. Based on his M.S. in Structural Engineering from the University destruction of structures in New York City and re-evaluated. The world trade center 1. Prevent progressive collapse by of the redundancy and robustness built into these initial observations, fire protection CTBUH events around the of Illinois at Urbana-Champaign. His principal Arlington Virginia, including the World Trade towers “were the first structures outside of development and nationwide adoption of experience with CTLGroup has included: structural the structures. recommendations included the following: investigation and assessment, structural analysis and Center’s twin towers (WTC 1 and WTC 2). This the military and nuclear industries whose standards and code provisions, and design calculations for evaluation of existing unprecedented attack subjected both towers Although WTC 1 and WTC 2 ultimately design considered the impact of a jet 1. Active fire suppression should be develop a standard methodology – WTC: Ten Years On structures, solutions for construction problems, construction-related repair and rehabilitation of to extreme load conditions far beyond those collapsed, they withstood initial structural airliner, the Boeing 707” (FEMA, 2002. accomplished through the use of supported by analytical design tools and existing structures, on-site observation and considered during design. damage for 102 and 56 minutes, respectively. However, these loads fell far short of the redundant systems. practical design. construction services, administration, development of extraordinary loads applied by a far larger, world. repairs and observation of execution of remedial Redundant and robust exterior steel frame 2. To be effective, passive fireproofing must 2. Develop national standards for (1) structural demolition and repairs. Impact by Aircraft and hat truss construction provided for load faster moving aircraft on September 11. remain adhered after impact or conducting wind tunnel testing of Current geopolitical landscapes and Gene Corley Each of the twin towers was struck by redistribution around areas of impact damage, deformation. prototype structures and (2) estimating Gene Corley leads structural evaluation projects commercial Boeing 767-200 aircraft, each with bridging large, damaged areas. In the case of accompanying motivations have raised wind loads and their effects on tall related to industrial, transportation and parking 3. Passive fireproofing must demonstrate facilities, bridges and buildings. His wide range of estimated gross weights in excess of 124,300 WTC 2, photographic evidence shows more the standard of credible hazards. post-event effectiveness. buildings for use in design. experience includes: evaluation of earthquake, fire and kilograms (274,000 pounds), including 37,900 than 30% of south face columns were blast damaged buildings and bridges, investigation of 3. Develop criteria to enhance tall building 24 Introduction distress in prestressed concrete structures, repair of liters (10,000 gallons) of jet fuel, and at speeds destroyed over five stories (FEMA, 2002). Fire Protection and Fire Suppression performance by limiting sway under parking garages damaged by corrosion, evaluation between 750 and 950 km/h (470 and 590 Calculations show that, if not for the damage Passive fire protection was provided for many and repair of high-rise buildings, stadiums, silos and NIST Recommendations lateral load design conditions (e.g., winds bridges, design and construction or repair of mph). These impacts severely damaged caused by fire, these structures could have structural elements. Spandrels, columns, and Following congressional hearings on May 1, and earthquakes). prestressed conventionally reinforced, precast and structural systems, ignited widespread fires, remained globally stable (see Figure 1 and 2). trusses received spray-on application of 60 Book Reviews cast-in-place concrete, foundations and structural steel 2002, the National Institute of Standards and facilities. and ultimately led to collapse of both low-density fireproofing material with a 4. Evaluate the technical basis for Based on these initial observations, structural Technology (NIST), was authorized to produce Gene is one of the world’s foremost experts in structures. Aircraft impact severely damaged specified fire rating of two or three hours. This determining appropriate construction recommendations included the following: a comprehensive study to develop analyzing buildings damaged by bombs, earthquakes, exterior steel columns and the interior core. material has limited capability to remain classification and fire rating requirements fire and tornadoes. He led the federal investigation 1. Structural designers should consider a recommendations for code changes. This into the September 11, 2001, collapse of the World Additionally, damage to active fire suppres- adhered to substrate material under (especially for tall buildings), and explicitly robust and redundant design philosophy. work was completed and many Trade Center’s twin towers. He also conducted the sion systems such as sprinklers, and passive deflection, and is not designed to resist consider factors including: Books on the World Trade investigation of the 1995 collapse of part of the Murrah Individually, structural elements should be recommendations for changes in the Federal Building caused by the Oklahoma City systems such as fireproofing was severe. abrasion or impact. Active fire suppression • timely access by emergency responders 26 Planning the World Trade bombing, and served as expert advisor during the designed to retain sufficient capacity after International Building Code have been would have been provided by standpipes and investigation and trial resulting from the 1993 fatal fire yielding, and be globally configured to adopted. Early observations and • the extent to which redundancy in active at the Branch Davidian complex in Waco, Texas. sprinkler systems that had been retrofitted Early Observations and Recommendations provide multiple load paths after recommendations centered around three fire systems should be credited for into the towers. individual element failures. major areas of concern unique to tall occupant life safety ® Center Structural Performance Sprinkler systems remain operational so long buildings: ability to remain globally stable Despite the terrible loss of life and property, Center: 40 Years Apart as piping is intact, and adequate water supply Jan Klerks 32 | Evolution of Building Code Requirements in a Post 9/11 World CTBUH Journal | 2011 Issue III CTBUH Journal | 2011 Issue III Evolution of Building Code Requirements in a Post 9/11 World | 33 61 Letters 30 Wider Impacts: Tall Buildings Feedback and comments as a Viable Proposition “The WTC showed that we lack an Leslie E. Robertson, William 61 Diary Baker & Eugene Kohn Upcoming tall building events adequate definition of competence…

32 Evolution of Building Code 62 Meet the CTBUH What we truly need is to legislate Requirements in a Post 9/11 Dario Trabucco World competence, not standardized David Drengenberg & Gene 63 CTBUH Organizational solutions.” Corley Member Listings Jose Torero, page 36

CTBUH Journal | 2011 Issue III Inside | 3 Interview Talking Tall: The Global Impact of 9/11

Contributors “All memories fade over time, although 9/11 Alastair Collins, CTBUH Country Representative: South Africa will go down in history as one of the most e: [email protected]

Ryszard Kowalczyk, CTBUH Advisor cynical attacks outside of a war. Humans, as Bialystok University of Technology, Warszawa, Poland e: [email protected] New Yorkers showed post 9/11, continually Simon Longuet-Higgins Country Representative: New Zealand show their amazing ability to dust themselves Beca Group 21 Pitt Street Auckland 1141, New Zealand off and get on with life, which must really t: +64 9 300 9000, f: +64 9 300 9300 e: [email protected] frustrate the forces of darkness.” Ronald Mischek, Country Representative: Austria (to 2010) Mischek Ziviltechniker Ges.mbH An interview with CTBUH Country Representatives by Jan Klerks, CTBUH Communications Billrothstr 2 Vienna 1190, Austria Manager/Journal Editor t: +43 1 3607 0202, f: +43 1 3607 0899 e: [email protected] Just as many Americans still remember exactly where they were when they heard the news

Masayoshi Nakai, CTBUH Country Representative: Japan that US president John F. Kennedy had been shot, most people will likely remember what Takenaka Corporation they were doing on September 11, 2001. Social media was not as developed as it is nowadays, 1-1-1, Shinsuna, Koto-ku Tokyo, 136-0075, Japan but nonetheless, the collapse of the Twin Towers of the World Trade Center in New York City t: +81 3 6810 5197, f: +81 3 6660 6095 was news that quickly spread and shocked people all around the world. In this article the e: [email protected] Council has delved into its international representation, to ask our country representatives Tiyok Prasetyoadi, how these events have influenced tall building development in their respective countries in CTBUH Country Representative: Indonesia Planning & Development Workshop Architects the past 10 years. Plaza 3 Pondok Indah Blok B-5 Jl. TB Simatupang, Jakarta 12310, Indonesia t: +62 21 7590 6177, f: +62 21 7590 6177 Japan’s immediate response was to launch an 1. a plane being hijacked given the various e: [email protected] investigation. The Council’s Japan types of anti-hijacking policies in other Felino Palafox, CTBUH Country Representative: Philippines Representative Masayoshi Nakai of the countries Palafox Associates Takenaka Corporation commented: “Following 11-F, 6782 Ayala Avenue 2. a large-scale fire leading to building Makati City 1226, Philippines the events of 9/11, a Japanese risk collapse t: +63 2 812 1254, f: +63 2 893 9197 management consultancy firm conducted a e: [email protected] study to assess the chances of three disastrous 3. an aircraft crashing into a building, based Juneid Qureshi, events related to supertall buildings: on the actual conditions of aviation CTBUH Country Representative: Singapore administration in each country. Meinhardt Pte. Ltd. 168 Jalan Bukit Merah #09-01 Surbana One, 150168 Singapore t: +65 6377 9262, f: +65 6274 0788 [email protected]

Elena Shuvalova, CTBUH Country Representative: Russia Lobby Agency 4th VerkhnyMikhailovsky Projezd, 10-3-172 115419 Moscow, Russia t: +7 903 298 9346 www.lobbyagency.ru

Hatice Sozer, CTBUH Country Representative: Turkey Energy Institute Istanbul Technical University Ayazaga Campus 34469 Maslak, Istanbul, Turkey t: + 90 212 285 3941, f: +90 212 285 3884 e: [email protected]

Dario Trabucco, CTBUH Country Representative: Italy IUAV University of Venice Ex-DCA - Terese Dorsoduro 2206 30123 Venezia, Italy t: +39 347 416 1732 e: [email protected]

50 | Talking Tall: The Global Impact of 9/11 CTBUH Journal | 2011 Issue III In 2004, the study concluded that the chance not just organized terrorists are a threat, but of any of these events happening in any of that tall buildings can be a targeted for the major cities in Japan was remote.” anyone seeking a stage to make a point” (see A number of countries did not have a Figure 2). particularly active tall building industry in the In some countries, land scarcity has proven to days of 9/11. Juneid Qureshi of Meinhardt be such a strong driver for tall buildings that Singapore explains: “Until the recent there simply is not much room for emotional completion of the 68-story Bitexco Financial considerations, Juneid Qureshi comments: Tower, Vietnam had been rather modest “The events of 9/11 have not had an unduly when it comes to tall building development. adverse impact on the perception of tall As such the events of 9/11 had a relatively buildings in Singapore. Given our land small effect on the industry in Vietnam at the scarcity, building tall is not an option but a time.” Turkey Representative Hatice Sozer, of necessity. Therefore, following the events of Istanbul Technical University, reports a similar 9/11, industry professionals have taken a experience in Turkey: “The event actually did pragmatic approach to adopt additional, and not directly affect the high-rise industry in sometimes restrictive security considerations, Turkey because, in contrast to today’s as an unavoidable fact of life that must be Figure 2. Pirelli Tower after plane crash in 2002 © Marcel environment, there were not many tall managed. This has made building buildings. Now the tall building industry is professionals consider security aspects as key there is a difference between the technical becoming increasingly active, even after the elements in the design process and standards in America and here in Europe. The economic crisis. Political and economic implement appropriate measures from the public was satisfied with the argument that a developments, such as the development of concept design stage of a project.” building with a concrete structure, which is oil prices, have had a far greater impact on Philippine Representative Felino Palafox, of the case with most tall buildings in Austria, Turkey’s tall building environment than the Palafox Architects, pointed out the same would have responded differently than a events of 9/11.” argument, and also mentioned an interesting building with a steel structure. As such it was A country’s economic forces being more cultural response: “From a social point of view, suggested that a concrete building might not influential than emotional issues associated the response has been to build no more twin have collapsed in similar circumstances. with 9/11 is something Ryszard Kowalczyk, of towers. Feng Shui believers feel that twin Obviously this opinion was the interpretation Bialystok University of Technology, observed towers bring bad luck, as they resemble two of the general public, and not the opinion the in Poland. “The destruction of the World Trade candles for the dead during a wake.” country’s structural engineers. Due to 9/11, it Center gave opponents of tall buildings in After the tall building world realized what had has become even more typical for the public Warsaw new arguments to stiffen their happened, much attention was focused on to think negatively about steel construction in resistance. However, at the time of 9/11, a issues related to building security, and of high-rise buildings.” construction boom had already begun as a course the structural safety of tall buildings. The best way to ensure that buildings will not result of a strong Polish economy creating a Some of these discussions focused on the collapse as a result of an extreme event is big demand for grade-A office space . This structural material. Austria’s Ronald Mischek of through the prevention of those events. proved to be a strong factor, and the Mischek Ziviltechniker said: “In terms of Anyone who has entered a hotel or office  arguments against tall buildings were construction, it was pointed out in Austria that discussed but quickly rejected,” commented Kowalczyk (see Figure 1). ...debris Seven months after 9/11, the Italian tall building world had to absorb the impact of a similar event on a smaller scale. On April 18, 2002, a small plane crashed into the upper The debris [from the WTC] was dumped into the Hudson floors of the Pirelli Tower in Milan (the motive River,“ beginning what would become the biggest landfill in the behind the event is still unclear). Country city’s history, even dwarfing the tons of dirt and rocks that had to Representative Dario Trabucco, of IUAV be disposed of when the subways were built sixty years University of Venice, said: “As far as Italy is concerned, I would say that 9/11 has not earlier. affected the perception of tall buildings very ” much. Our own ‘4/18’ on the other hand has Bill Harris in his book “The World Trade Center. A Tribute,” 2001: 49–51 had a significant impact since it showed that

CTBUH Journal | 2011 Issue III Talking Tall: The Global Impact of 9/11 | 51 tower in the past ten years must have noticed contrary to several other urban development severity of a terrorist attack. These a more tightened security policy. Such are the laws, which allow buildings of significantly recommendations cover in significant detail a experiences of PDW Architects’ Tiyok greater height.” wide range of issues related to planning, Prasetyoadi of Indonesia. “The effect of the Instead of shaping their own code, some design and construction of tall buildings. events is most evident in the lower part of tall countries look to areas that have well- While it is not mandatory to implement the buildings. First, in the planning of every established regulations of tall buildings. recommended measures, the guidelines development the security requirements are “Turkey has borrowed most of their high-rise provide a list of options of good security more stringent, especially for buildings related code from the USA or Europe. Any practices and considerations to help building occupied by multi-national companies. changes in their codes were adapted here as owners and professionals implement Second, the design has to include a space to well,” comments Sozer. Felino Palafox pragmatic and practical security procedures, inspect cars before they enter the building mentioned that the Philippines are waiting for physical protection concepts, and security premises. Before entering the building lobby, the USA to change their codes. “It’s a technology.” there are now X-ray security checks, especially challenge to convince clients to spend more in international hotels and offices. money on the anticipated new requirements.” Additionally, some projects are now being Concluding considerations designed with blast-proof windows on the Tall building code, or rather the lack of it, is a Ten years is a good amount of time to reflect ground floor level.” relevant issue in Russia. “Perhaps more on the events of 9/11, draw rational dangerous than terrorism is the lack of conclusions from it, and move on. Some of Hatice Sozer also mentioned the topic of dedicated codes for tall buildings. The only emergency preparedness: “9/11 raised issues the reflections have a more philosophical document that currently regulates high-rise character, such as Ryszard Kowalczyk’s in Turkey regarding preparedness and development in modern Russia is a set of recovery, such as back-up data storage and comment: “Unexpected attacks through temporary regulations and standards for the unusual means really are the exception.” information processing repositories. Many design of mixed-use high-rise buildings and companies re-evaluated their ability to Kowalczyk continues: “It can always be argued complexes in Moscow, which was adopted in that there is more to be done politically in respond to these kinds of emergencies, in an late 2005 as regulation MGSN 4.19-2005,” attempt to avoid haphazard responses.” order to prevent terrorist attacks than in the commented Country Representative Elena field of architecture and civil engineering.” The If there is one single place that the general Shuvalova, of the Lobby Agency. Shuvalova industry has learned an important lesson and public has noticed a change in security policy, continues: “This document currently serves as come to the understanding that, as Ronald it is most definitely the airport. New Zealand’s the guideline to other regions of Russia where Mischek puts it, “You cannot build a tall Representative Simon Longuet-Higgins, of tall buildings are being built. I consider the building with a 100% guarantee that nothing Beca Group, commented on the matter events of 9/11 to be of eminent importance will happen.” saying: “The people of New Zealand are to Russia because it forced us to think about travelers and probably the most noticeable developing new technologies and shaping A deeper meaning of 9/11 and the adjustment we have had to cope with is the new regulations and requirements. The lack of international response is represented by a increased security at airports. Anecdotally federal and regional regulation in the sphere quote from South Africa Representative there has also been a move to travel West of high-rise construction makes our Alistair Collins: “All memories fade over time, rather than East when heading for Europe to authorities very cautious about allowing although 9/11 will go down in history as one avoid the hassles of travelling through the US projects, and causes them to cancel many of of the most cynical attacks outside of a war. with the added visa and border security issues the more ambitious schemes.” Humans, as New Yorkers showed post 9/11, this now entails.” have time and time again shown the amazing A less stringent but equally relevant strategy is ability to dust themselves off and get on with An interesting effect of air travel and tall to compose guidelines instead of code, as life, which must really frustrate the forces of buildings is observed in Indonesia by Tiyok reported by Juneid Qureshi: “The Ministry of darkness. This resilience was evident when, a Prasetyoadi. “The military airport in East Home Affairs has published comprehensive year or two after 9/11, we surveyed the Jakarta is increasingly becoming involved in guidelines in 2005 and 2010 for enhancing occupiers of a number of London’s tall building height regulation. This affects tall building security in Singapore as part of the buildings and found that the vast majority of building development in Jakarta’s Central effort to put in place the necessary measures occupants felt safe in them. After a short and Business District, which is within 15 kilometers and infrastructure to protect the city. The appropriate appraisal of the typology, the (9.3 miles) of the flight zone. Our quick study guidelines are a compilation of international industry has now established a proper shows that building heights will be limited to best practices in building security which perspective on tall buildings, and the number between roughly 150 and 200 meters (500 present detailed practical and cost-effective of these projects continues to increase in the and 650 feet), depending on the relative security measures and building design post 9/11 world, serving as a firm answer to position to the airport. This regulation is considerations that could help lessen the terrorists everywhere.” 

52 | Talking Tall: The Global Impact of 9/11 CTBUH Journal | 2011 Issue III