CTBUH Technical Paper

http://technicalpapers.ctbuh.org

Subject: Architecture/Design

Paper Title: Closing the Gap between Fantasy and Reality: Pushing Current Technologies

Author(s): Terri Meyer Boake

Affiliation(s): School of Architecture, University of Waterloo

Publication Date: 2014

Original Publication: CTBUH Journal 2014 Issue III

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 Unpublished conference paper 5.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 Unpublished

© Council on Tall Buildings and Urban Habitat/Author(s) About the Council

The Council on Tall Buildings and Urban Habitat, based at the Illinois Institute of Technology in CTBUH Journal Chicago and with a China offi ce at Tongji International Journal on Tall Buildings and Urban Habitat University in Shanghai, is an international not-for-profi t organization supported by architecture, engineering, planning, development, and construction professionals. Founded in 1969, the Council’s mission is to disseminate multi- Tall buildings: design, construction, and operation | 2014 Issue III disciplinary information on tall buildings and sustainable urban environments, to maximize the international interaction of professionals involved in creating the built environment, and to make Special Issue: CTBUH 2014 Shanghai Conference the latest knowledge available to professionals in a useful form. Case Study: China Zun, Beijing The CTBUH disseminates its fi ndings, and facilitates business exchange, through: the Closing the Gap Between Fantasy and Reality publication of books, monographs, proceedings, and reports; the organization of world congresses, Hybrid Timber Construction for Sustainable Tall Buildings international, regional, and specialty conferences and workshops; the maintaining of an extensive Building Services as a Force for Sustainable Vertical Urbanism website and tall building databases of built, under construction, and proposed buildings; the Learning From 50 Years of Hong Kong Skybridges distribution of a monthly international tall building e-newsletter; the maintaining of an Tall Buildings in Numbers: Vertical Greenery international resource center; the bestowing of annual awards for design and construction excellence and individual lifetime achievement; the management of special task forces/working groups; the hosting of technical forums; and the publication of the CTBUH Journal, a professional journal containing refereed papers written by researchers, scholars, and practicing professionals.

The Council is the arbiter of the criteria upon which tall building height is measured, and thus the title of “The World’s Tallest Building” determined. CTBUH is the world’s leading body dedicated to the fi eld of tall buildings and urban habitat and the recognized international source for information in these fi elds.

Council on Tall Buildings and Urban Habitat

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ISSN: 1946 - 1186 Inside

News and Events Features 34 Architecture/Design Closing the Gap between Fantasy and Reality: Pushing Current Technologies into the Future The tall building is a discrete architectural type. The causal aspects of its evolution can assist in determining which aspects will be of the most benefit 02 This Issue 52 Tall Buildings in Numbers in pushing the idea forward. If tower-type buildings are symbols of the ideals and aspirations of the civilizations of any period in history, then what should our current response be based upon our technical achievements?

Antony Wood, Green Walls in High-rise Terri Meyer Boake The age of the iconic skyscraper has come to There is such a significant gap between the be dominated by a combination of the physical realities – and sheer mass – of Author preference for the stylistically unique in skyscraper design and the fantastical images Terri Meyer Boake, Professor conjunction with the quest to build tall. The of skyscraper “dreams” that we see in visionary Figure 2. The Dragonfly urban vertical farm concept in New York. Figure 3. The Asian Cairns farmscraper concept in Shenzhen. School of Architecture © Vince Callebaut Architects. Source: http://inhabitat.com © Vince Callebaut Architects. Source: http://hyperallergic.com University of Waterloo uniformity and rectilinear nature of proposals and competition entries. We Cambridge, Ontario, Canada International Style architecture that dominated seldom see the same abandon in the design progress in megacolumns, outriggers, diagrids, compelling and often controversial area of debate, particularly with reference to project Executive Director Buildings t: +1 416 636 0031 f: +1 416 636 0323 tall building design through the better part of of museum types, for instance. Although composite construction, concrete pumping design. As the planet urbanizes, the tall proposals as they are introduced in the media. e: [email protected] the 20th century has given way to unrestrained conceptual explorations for smaller building technologies, high-performance envelopes, building is being claimed as the solution. https://uwaterloo.ca/ expression that is reliant on pushing the limits types might push the limits on form and and vertical transportation. But it has not However, the questions “how tall?” and “how Many of these blur the lines between digital of technology, including the structural materials, often as a direct result of digitally necessarily kept up with the fantasy visions of dense?” have not been properly addressed. design, technical aspirations and present Terri Meyer Boake Terri Meyer Boake has been a full professor in the capabilities of materials and systems, as well as driven liberation, they are usually grounded in towers that we see in renderings and realities. A great number of the most School of Architecture at the University of Waterloo the methods used to calculate and fabricate some sort of material concern. competition entries, many of which ignore speculative skyscrapers have a “green” agenda. since 1986, teaching in the areas of building construction, architecturally exposed structural those systems. This encompasses many present-day material and construction realities The Design Potential of Controversy Sustainable themes include the incorporation steel, environmental design and film. She researches evolving areas of digital design. The Evolo Skyscraper Ideas Competition has – and gravity. Many of these proposals may of wind turbines and vertical farms that push steel construction for the Canadian Institute of Steel Construction, working with them to publish the CISC been running since 2006 to inspire an interest include genuinely inspirational ideas, but they Recent stylistic and structural changes in the limits well beyond what has been 07 Debating Tall: 54 Talking Tall: James Robinson Guide for Specifying Architecturally Exposed Structural Tall buildings presents one of the most in the design of tall buildings. The winning presently belie construction. However, it is the tower typology have potentially made the tall accomplished to date in projects such as the Steel. She has published Understanding Steel Design: An Architectural Design Manual (Birkhäuser 2012), challenging design problems that we face. entries have become increasingly fantastic, as nature of “ideas competitions” to bring forward building a more engaging building type as Pearl River Tower in Guangzhou by SOM or the Diagrid Structures: Systems, Connections, Details What is being constructed today will impact illustrated in Figure 1. This is not to suggest compelling visions of the future of architecture well as perhaps a more contentious one. This Wuhan Greenland Center by Adrian Smith + (Birkhäuser 2014) and is presently writing Architec- turally Exposed Structural Steel, due out in January our environment for many decades to come. that “ideas competitions” are invalid (see Figures 2 and 3). What should be the focus provides an interesting opportunity for Gordon Gill Architecture (see Figures 4 and 5). 2015. She has lectured worldwide on applications in Skyscrapers are not readily demolished. They approaches for eliciting innovation; rather, the of future skyscraper developments? architecturally exposed structural steel. Is There a Height Threshold Learning From 50 Years of are massive buildings with extremely lack of basic material and structural concerns She travels widely to present at international confer- ences and document buildings. Her photographs significant structural systems that must create makes such competition results more suited The winning entries from the 2014 Evolo form the basis for her lectures, teaching and research livable spaces for thousands of people (inside to a digital industry such as film, and limits Competition clearly acknowledge the need for – many appearing in the CTBUH Skyscraper Database. and outside) as they engage the city, and their applicability to the practice of towers that integrate high-speed vertical She is a member of the CTBUH Skyscraper Center which need to remain viable for a significant architectural design. transport systems, capture carbon, improve the for Optimum Sustainability? Hong Kong Skybridges Editorial Board. duration. air quality of cities, incorporate new materials, The technology of building tall has advanced use 3D-printing technologies, and generally significantly in the past 15 years – with major push a sustainable agenda. These are “fantasies” deserving of realistic exploration.

The situation may require that we step back and reconsider the tall building typology going Tall buildings presents one of the most forward, to better direct our energies towards “challenging design problems that we face. understanding how we can effectively build 08 Global News 58 Ask a CTBUH Expert: upon current technologies to create a more What is being constructed today will socially and environmentally responsive framework. There is a need to reconcile current impact our environment for many decades digital fantasies with the technical realities of what we can do in light of what we should do. to come. Skyscrapers are not readily st Highlights from last quarter’s Ron Klemencic The typology of the 21 -century tower has evolved from a commercially driven demolished. Figure 4. Pearl River Tower, Guangzhou uses its sculpted Figure 5. Wuhan Greenland Center. Figure 1. Light Park Floating Skyscraper, Evolo 2013: 3rd place. © Ting Xu/ optimization problem to a dynamic, form to direct wind toward turbines situates at the © AS + GG Architects ” Yiming Chen. Source: http://www.evolo.us/category/2013/ recesses in the façade. © SOM tall news archive Why are Tall Buildings Often 26 | Architecture/Design CTBUH Journal | 2014 Issue III CTBUH Journal | 2014 Issue III Architecture/Design | 27 Considered Safer Than Low-rise Buildings During Earthquakes?

40 Structural Engineering Case Study Developing Hybrid Timber Construction for Sustainable Tall Buildings In the near future, timber will form a much bigger part of the built environ- ment. This paper chronicles projects that redefine the possibilities of timber to help support this development. Working on the LifeCycle Tower (LCT), the author and colleagues explored the full and still-undiscovered potential of 14 China Zun Tower, Beijing using wood for high-rise buildings. Using engineered wood combines the CTBUH potential for prefabrication and rapid construction with lower embodied Carsten Hein energy and the potential to delay carbon emissions for a building’s lifetime. It recognizes that timber is best used in conjunction with other materials taking Author advantage of the attributes of each material. Use of timber is optimized when Robert Whitlock, Li Lei, Dr. Luo Carsten Hein, Structural Engineer Arup Deutschland GmbH it achieves fully integration design with building services, matching the Joachimsthalerstraße 41 D 10623 Berlin, Germany acoustic, dynamic and fire performance of conventional alternatives. Figure 2. LCT One, Dornbirn, Austria. © CREE/Architekten Hermann Kaufmann Figure 3. Illwerke Zentrum Montafon, Montafon, Austria. © CREE/Norman A. Müller t: +49 30 885 910 70 f: +49 30 885 910 10 e: [email protected] CREE/Haus der Zukunft Project, 2009 high-rise tower, attempting to use timber for as between concrete and timber to enable The slab had been built with concrete of 80 The eight-story LCT One used a concrete core Nengjun & Dr. Liu Peng CTBUH Chair Transition: www.arup.com 04 much of the structure as possible. The research composite action. The stability core and the millimeters’ thickness. Additional aggregates for stability, which also provided the main exit A multidisciplinary approach is essential to comprised building permit calculations for all columns were designed to use glue-laminated had to be used for production of the concrete route in case of fire. Whilst the fire concept Carsten Hein Carsten Hein is a structural engineer by profession achieve the aim of a sustainably using timber engineering services involved, including wood panels (glulams), the core being slab to avoid flaking of concrete cover, and to had envisaged a fully-sprinklered system, the and joined Arup in 1996, where he developed a in the urban environment. While the structure, MEP, façade, fire, acoustic, and assembled from 2.4-meter panels. The façade guarantee concrete integrity for the required building permit allowed removal of the strong interest in designing timber structures. In 2004 he started working with Jürgen Mayer H. on the environmental advantages of timber are building physics. The construction was was conceived as consisting of 2.7-meter-wide 90 minutes. For acoustic performance, a sprinkler system because of the robust Passing the Gavel Parasol Metropol in Seville, Spain leading the timber widely recognized, the cost efficiency of designed to meet the requirements of modules with integral glulam columns. An sound-absorbing raised floor was required, as fire-safety strategy. team in the office. In 2009, he led the design team for the multidisciplinary research project LifeCycle Tower. sustainable construction will be the main European standards, and of the German and approximate cost comparison of the chosen well as an additional self-levelling floor screed. At the same time, the MSTRN global timber network driver of an increased use of timber. In 2009, Austrian building regulations. timber-concrete-composite construction for The system returned an adequate performance. The façade system was also slightly modified within Arup began operations. the Arup team carried out research in the LifeCycle Tower with a traditional concrete As expected, tests proved a 3-to-6-dB higher from the research concept. It now featured up Carsten Hein has worked on various timber projects, Timothy Johnson & David Malott always investigating the possibilities of the material cooperation with the Austrian developer The floors of the LCT were conceived as frame structure indicated that using timber sound insulation than listed by product to 12-meter-wide prefabricated panels, with and trying to push the boundaries for the use of CREE, funded by the Austrian government timber-concrete-composite (TCC) slabs, using a would generate 10% to 15% higher costs. It specifications. But it remained questionable if the columns mounted to the back of these timber. initiative “Haus der Zukunft.” The architect was concrete slab supported by timber beams, with was therefore agreed that a prototype would this was the most cost-effective solution. panels. This was a valuable step to reduce the Hermann Kaufmann ZT GmbH, Austria. a stiff connection between the two to provide be constructed, minimizing the sizes of all the However, in terms of fire performance, it was cost of construction and to improve the Further collaborators included Wiehag, an composite action (see Figure 1). members to achieve a more economical very successful, achieving an REI 90 (90 minutes speed of erection. Austrian timber fabricator, and the Technical solution. fire resistance) certificate from the PAVUS Test University of Graz, with a former colleague of While the structural requirements could have Institute in the Czech Republic (see Figure 4). At this point, the cost assessment was still not the author, Prof. Brian Cody. been fulfilled by timber alone, or by a 60- to As the concrete contractor was not satisfactory; additional measures for the The floors of the 80-millimeter-thick concrete flange for the LCT One: The Prototype, 2011 commissioned at this point, it was decided to concrete and certification for fire resistance “LCT were conceived as From the outset, the team considered a timber beams, fire regulations required 100 use the Czech facility and a concrete contractor resulted in extra costs. The cost comparison Research 59 CTBUH on the Road modular construction system to allow for millimeters of thickness; acoustic requirements Based on Arup’s concept, CREE built an nearby to build the test elements – so only the became more difficult with more details at timber-concrete- maximum prefabrication capability. The team called for 120 millimeters. Notches in the tops eight-story prototype in Dornbirn, Austria (see timber had to be transported from Austria. construction stage – there was no developed the concept for a 20-story of the beams created a structural interlock Figure 2), followed by a 10,000-square-meter composite (TCC) slabs, office building nearby in Montafon (see Figure 3). These projects were designed by local CTBUH events around the world using a concrete slab engineers Merz Kley Partner, with Hermann Kaufmann again as architect. As agreed during supported by timber the research, both these projects pushed the beams, with a stiff boundaries of timber construction, as all the 22 Towards Sustainable Vertical main elements were slightly undersized connection between the compared to code-based fire and acoustic calculations. Testing was then undertaken of two to provide the slab system to demonstrate compliance. The test results were used to further develop Urbanism: Highlights from composite action. Figure 1. Timber-Concrete-Composite (TCC) slab. After all the walls are installed, the floor slabs, which were fabricated the system. Figure 4. The prototype slab of LCT ONE was tested for fire resistance. After some modification the test proved 92 59 Diary ” with a hole in each corner, slide over the pins in the glulam posts. © CREE minutes of fire resistance, confirmed by an REI 90 certificate from PAVUS. the Shanghai 2014 Upcoming tall building events 20 | Structural Engineering CTBUH Journal | 2014 Issue III CTBUH Journal | 2014 Issue III Structural Engineering | 21 Conference Program Daniel Safarik 60 Reviews Review of new books in the Tall Buildings in Numbers Building Functions Institutional 34 Closing the Gap between 1 Across the 18 case studies, there are four CTBUH Library 52 Hotel Oce Green Walls in High-Rise Buildings 4 6 different types of building functions. Green walls are thus clearly applicable across For centuries, green walls have been used to shade building walls and atriums, to shield buildings The Met multiple building types and functions. Bangkok, 2009 Residential 7 from wind, and to cultivate agricultural plants. Now, as the world population urbanizes, green Building Height: 231 meters Fantasy and Reality: Pushing walls have become a significant tool in the quest for greater sustainability in the tall-building field. Stories: 69 The latest CTBUH technical guide, Green Walls in High-Rise Buildings, provides a thorough Solaris Total surface area of green coverage: 7,170 m2 investigation of the methods used around the world for implementation of vertical vegetation at Singapore, 2011 Building Height: 79 meters Largest green coverage on a 2 height. In commemoration of the release of this important guide, Tall Buildings in Numbers Stories: 15 single façade: 3,385 m (18%) Green coverage of total Total surface area of green profiles the 18 case study buildings included. façade: 14% Current Technologies into coverage: 3,065 m2 61 Comments To purchase your copy of Green Walls in High-Rise Buildings visit: https://store.ctbuh.org Largest green coverage on a single façade: 1,449 m2 (N/A) IDEO Morph 38 Tower Green coverage of total Bangkok, 2013 façade: 15% Building Height: 134 meters Location of Case Studies and Size/Percentage Stories: 32 ACROS Fukuoka Total surface area of green Fukuoka, 1995 the Future of their Green Coverage coverage: 5,850 m2 Building Height: 60 meters Stories: 14 Pasona Headquarters Feedback on past Journal issues Largest green coverage on a Tokyo, 2010 single façade: 1,276 m2 (66%) Total surface area of green Building Height: 34 meters coverage: 5,326 m2 Green coverage of total Stories: 9 façade: 23% Largest green coverage on a single façade: 5,326 m2 (84%) Total surface area of green coverage: 1,224 m2 Green coverage of total Terri Meyer Boake Largest green coverage on a façade: 28% single façade: 720 m2 (37%) Green coverage of total façade: 20% One PNC Plaza Athenaeum Hotel Pittsburgh, 2009 London, 2009 Newton Suites Building Height: 129 meters Building Height: 48 meters Singapore, 2007 Stories: 30 Stories: 9 Building Height: 120 meters Meet the CTBUH Stories: 36 Gramercy Skypark 62 Total surface area of green 2 Total surface area of green Makati, 2013 coverage: 221 m 2 Total surface area of green coverage: 256 m Building Height: 244 meters Largest green coverage on a coverage: 1,274 m2 Largest green coverage on a Stories: 73 single façade: 221 m2 (5%) single façade: 159 m2 (9%) Largest green coverage on a 2 Green coverage of total single façade: 734 m2 (21%) Total surface area of green coverage: 189 m Green coverage of total façade: 1% Largest green coverage on a single façade: 138 m2 (1%) 40 Developing Hybrid Timber façade: 9% Green coverage of total Son Dang façade: 10% Green coverage of total façade: 0.4%

PARKROYAL on Pickering Singapore, 2012 B3Hotel Virrey Building Height: 89 meters Construction for Sustainable Bogota, 2011 Stories: 15 Building Height: 30 meters Total surface area of green coverage: 4,827 m2 Stories: 9 Largest green coverage on a single façade: 2,257 m2 (16%) Total surface area of green Green coverage of total façade: 11% coverage: 264 m2 Largest green coverage on a single façade: 264 m2 (49%) Trio Apartments Tall Buildings Green coverage of total Sydney, 2009 Building Height: 39 meters 62 CTBUH Organizational façade: 15% Consorcio Santiago Hotel Intercontinental Bosco Verticale School of the Arts Helios Residences Stories: 16 Santiago, 1993 Santiago, 2011 Milan, 2013 Singapore, 2010 Singapore, 2011 Building Height: 58 meters Building Height: 52 meters Building Height: 112 meters Building Height: 56 meters Building Height: 94 meters Total surface area of green Stories: 17 CH2 Council House 2 coverage: 139 m2 Stories: 16 Stories: 27 Stories: 10 Stories: 20 Melbourne, 2006 Total surface area of green Largest green coverage on a Total surface area of green Total surface area of green Total surface area of green Total surface area of green Building Height: 42 meters 2 coverage: 2,293 m2 single façade: 139 m (5%) Carsten Hein coverage: 1,590 m2 coverage: 10,142 m2 coverage: 6,446 m2 coverage: 1,652 m2 Stories: 10 Largest green coverage on a Green coverage of total Largest green coverage on a Largest green coverage on a Largest green coverage on a Largest green coverage on a 2 Member Listing 2 Total surface area of green coverage: 420 m façade: 0.7% single façade: 2,066 m (43%) 2 2 2 2 single façade: 1,302 m (60%) single façade: 1,735 m (47%) single façade: 1,434 m (53%) single façade: 1,142 m (15%) Largest green coverage on a single façade: 420 m2 (19%) Green coverage of total Green coverage of total Green coverage of total Green coverage of total Green coverage of total Green coverage of total façade: 7% façade: 22% façade: 29% façade: 42% façade: 26% façade: 7%

The agriculture and The floors with green One Central Park, Sydney greenery in Pasona The Bosco Verticale, Milan, Italy, The tallest green wall in the guide walls at Consorcio, Singapore’s Parkroyal on Pickering (submitted too late to make the Headquarters, Tokyo, Japan, has the largest total percentage is at The Met, Bangkok, Thailand, Santiago, Chile, use 35% provides 215% of the greenery that guide) won the CTBUH 2014 Best has been attributed to 12% of green coverage in the guide, at rising about 200 meters in a thin less energy than the existed on the site before the building Tall Building: Asia & Australasia productivity gains and a 42% and the largest total surface- strip. The building’s overall green floors without green walls was built. award for its innovative use of 23% reduction in employee area coverage at 10,142 m2. wall coverage is about 14%. 46 Building Services as a Force in the same building. heliostats and vertical greenery. absences due to ailments. for Sustainable Vertical Urbanism in China Malcolm Laverick While the research project aimed for a maximum “use of timber, the construction of the prototype taught the engineers that ‘less might be more.’ Hybrid construction is the sustainable approach that now forms the basis of design. ” Carsten Hein, page 40

CTBUH Journal | 2014 Issue III Inside | 3 Architecture/Design Closing the Gap between Fantasy and Reality: Pushing Current Technologies Into the Future The tall building is a discrete architectural type. The causal aspects of its evolution can assist in determining which aspects will be of the most benefit in pushing the idea forward. If tower-type buildings are symbols of the ideals and aspirations of the civilizations of any period in history, then what should our current response be based upon our technical achievements?

Terri Meyer Boake The age of the iconic skyscraper has come to There is such a significant gap between the be dominated by a combination of the physical realities – and sheer mass – of Author preference for the stylistically unique in skyscraper design and the fantastical images Terri Meyer Boake, Professor conjunction with the quest to build tall. The of skyscraper “dreams” that we see in visionary School of Architecture University of Waterloo uniformity and rectilinear nature of proposals and competition entries. We Cambridge, Ontario, Canada International Style architecture that dominated seldom see the same abandon in the design t: +1 416 636 0031 f: +1 416 636 0323 tall building design through the better part of of museum types, for instance. Although e: [email protected] the 20th century has given way to unrestrained conceptual explorations for smaller building https://uwaterloo.ca/ expression that is reliant on pushing the limits types might push the limits on form and of technology, including the structural materials, often as a direct result of digitally Terri Meyer Boake Terri Meyer Boake has been a full professor in the capabilities of materials and systems, as well as driven liberation, they are usually grounded in School of Architecture at the University of Waterloo the methods used to calculate and fabricate some sort of material concern. since 1986, teaching in the areas of building construction, architecturally exposed structural those systems. This encompasses many steel, environmental design and film. She researches evolving areas of digital design. The Evolo Skyscraper Ideas Competition has steel construction for the Canadian Institute of Steel Construction, working with them to publish the CISC been running since 2006 to inspire an interest Guide for Specifying Architecturally Exposed Structural Tall buildings present one of the most challeng- in the design of tall buildings. The winning Steel. She has published Understanding Steel Design: An Architectural Design Manual (Birkhäuser 2012), ing design problems that we face. What is entries have become increasingly fantastic, as Diagrid Structures: Systems, Connections, Details being constructed today will impact our illustrated in Figure 1. This is not to suggest (Birkhäuser 2014) and is presently writing Architec- turally Exposed Structural Steel, due out in January environment for many decades to come. that “ideas competitions” are invalid 2015. She has lectured worldwide on applications in Skyscrapers are not readily demolished. They approaches for eliciting innovation; rather, the architecturally exposed structural steel. are massive buildings with extremely signifi- lack of basic material and structural concerns She travels widely to present at international confer- ences and document buildings. Her photographs cant structural systems that must create livable makes such competition results more suited form the basis for her lectures, teaching and research spaces for thousands of people (inside and to a digital industry such as film, and limits – many appearing in the CTBUH Skyscraper Database. outside) as they engage the city, and which their applicability to the practice of She is a member of the CTBUH Skyscraper Center Editorial Board. need to remain viable for a significant duration. architectural design.

The Evolo Skyscraper Ideas Competition “winning entries have become increasingly fantastic… the lack of basic material and structural concerns makes such competition results more suited to a digital industry such as film, and limits their applicability to the practice of architectural design. Figure 1. Light Park Floating Skyscraper, Evolo 2013: 3rd place. © Ting ” Xu/Yiming Chen. Source: http://www.evolo.us/category/2013/ 34 | Architecture/Design CTBUH Journal | 2014 Issue III Figure 2. The Dragonfly urban vertical farm concept in New York. Figure 3. The Asian Cairns farmscraper concept in Shenzhen. © Vince Callebaut Architects. Source: http://inhabitat.com © Vince Callebaut Architects. Source: http://hyperallergic.com

The technology of building tall has advanced optimization problem to a dynamic, particularly with reference to project significantly in the past 15 years – with major compelling and often controversial area of proposals as they are introduced in the media. progress in megacolumns, outriggers, diagrids, design. As the planet urbanizes, the tall composite construction, concrete pumping building is being claimed as the solution. Many of these blur the lines between digital technologies, high-performance envelopes, However, the questions “how tall?” and “how design, technical aspirations and present and vertical transportation. But it has not dense?” have not been properly addressed. realities. A great number of the most necessarily kept up with the fantasy visions of speculative skyscrapers have a “green” agenda. towers that we see in renderings and Sustainable themes include the incorporation competition entries, many of which ignore The Design Potential of Controversy of wind turbines and vertical farms that push present-day material and construction realities the limits well beyond what has been – and gravity. Many of these proposals may Recent stylistic and structural changes in tower accomplished to date in projects such as the include genuinely inspirational ideas, but they typology have potentially made the tall Pearl River Tower in Guangzhou by SOM or presently belie construction. However, it is the building a more engaging building type, as the Wuhan Greenland Center by Adrian Smith nature of “ideas competitions” to bring forward well as perhaps a more contentious one. This + Gordon Gill Architecture (see Figures 4 and compelling visions of the future of architecture provides an interesting opportunity for debate, 5). (see Figures 2 and 3). What should be the focus of future skyscraper developments?

The winning entries from the 2014 Evolo Competition clearly acknowledge the need for towers that integrate high-speed vertical transport systems, capture carbon, improve the air quality of cities, incorporate new materials, use 3D-printing technologies, and generally push a sustainable agenda. These are “fantasies” deserving of realistic exploration.

The situation may require that we step back and reconsider the tall building typology going forward, to better direct our energies towards understanding how we can effectively build upon current technologies to create a more socially and environmentally responsive framework. There is a need to reconcile current digital fantasies with the technical realities of what we can do in light of what we should do. The typology of the 21st-century tower has Figure 4. Pearl River Tower, Guangzhou uses its sculpted Figure 5. Wuhan Greenland Center’s distinctive floor evolved from a commercially driven form to direct wind toward turbines situated at the slots help to reduce the vortex shedding. recesses in the façade. © Tansri Muliani © AS + GG Architects

CTBUH Journal | 2014 Issue III Architecture/Design | 35 Contemporary towers can exploit the “growing digital capabilities and the interoperability of software systems that allow geometries to be translated from the design office to the engineer, and ultimately to the fabrication equipment. Within this, it becomes important to reconcile structural and material realities with digital dreams.” The idea of the sustainable skyscraper was the is to enable an aggressive construction time focus of the CTBUH 2012 World Congress frame of months rather than years, which Shanghai – Asia Ascending: Age of the contrasts significantly from actual tall building

Sustainable Skyscraper City. The conference construction in China at the present time. Sky Figure 6. Sky City, Changsha. © China Broad Group program made clear that the notion of the City also claims to be highly sustainable based sustainable skyscraper remains an oxymoron on the use of systems previously tested by systems. However, the structural typologies of and fairly elusive, requiring significantly more other Broad Group buildings. The building, in towers might provide a starting point for research and exploration, as evidenced by the terms of construction methods, speed and re-engaging in their design. Many visionary CTBUH 2014 conference theme; Future Cities: scale, seems to present the most imminent schemes depend on unrealistically light Towards Sustainable Vertical Urbanism. realization of a highly visionary skyscraper structural systems, eccentric loading and design. challenging cantilevers. This lightness makes Perhaps one of the most-discussed projects many schemes difficult to take seriously, when internationally has been Sky City by China we know the extreme challenges that need to Broad Group. The proposed 838-meter, Structure as an Expressed Aesthetic be overcome in order to execute heavily 220-story tower in Changsha, China, is a cantilevered projects like the CCTV Building in visionary and ambitious project (see Figure 6). The towers constructed to date represent the Beijing by OMA. Fortunately, our current crop of limitations of the technology of our time, as “visionary” projects being executed in reality do Sky City relies heavily on prefabrication, a the height of the tower is directly connected provide an inspiring, if not easily replicable, way methodology already tested on other China to the tensile capabilities of materials, in forward. Broad Group projects, such as their well- conjunction with the understood best publicized 30-story hotel built in 15 days. This arrangement of the gravity and lateral-load

Figure 7. The megacolumns of the Chow Tai Fook Centre, Guangzhou. Megacolumns Figure 8. The double-façade system of the Shanghai Tower. The system encloses have become the critical part of a tall building structure, and are also factors in their multi story atrium spaces that sit outside of the primary structural system, which is architectural expression. composed of megacolumns combined with outrigger floors.

36 | Architecture/Design CTBUH Journal | 2014 Issue III Many innovative and exciting projects are interoperability of software systems that allow and erection of the systems as part of the being realized that either directly express their geometries to be translated from the design architectural design problem (see Figure13). structural system (see Figures 7 and 8) – as in office to the engineer, and ultimately to the diagrid towers – or combine the heavier fabrication equipment. Within this, it becomes megacolumn and outrigger systems necessary important to reconcile structural and material Façades Much More than Skin Deep to achieve extreme heights with lighter, more realities with digital dreams. The exciting geometrically versatile structural systems – opportunities of the diagrid and other steel Building to extreme heights has literally put a such as seen in the new Shanghai Tower. There structures lie in understanding the fabrication lot of pressure on façade design. Sustainable, is a rich history of expressive structure already established in Asia that has served to successfully transform banal corporate towers into icons of the future (see Figures 9 and 10).

Diagrid structures are chosen by designers for a reason: they can support challenging geometries, as they have ultimate flexibility. What is common to most applications is the ability of the diagrid to provide structural support to buildings that are non-rectilinear, adapting well to highly angular and curved forms (see Figure 11). The perimeter diagrid in its purest form is capable of resisting all of the gravity and lateral loads on the structure without assistance of a traditional core, enabling some pronounced deviations from typical structural types that are entirely dependent on a core for stability. The tallest constructed diagrid tower is Guangzhou IFC, by Figure 9. In 1985 the Hong Kong and Shanghai Bank by Figure 10. The use of the diagonal as a form-giving de- Foster + Partners launched the use of highly expressive vice transforms the Bank of China into an iconic tower Wilkinson Eyre Architects, which stands at 439 structure and prefabricated components into the realm that is visually distinct from the surrounding, more meters (see Figure 12). of tall building design. traditional skyscrapers in Hong Kong.

Advanced Computer Modeling’s Impact

The development of BIM (Building Information Modeling) has been critical to ensuring the successful design and fabrication of highly complex buildings. Geometric complexity requires a very high level of accuracy, and makes the assessment of loading on members and connections far more challenging than rectilinear structures that can be reduced to simple, determinate transfers of load. The use of such software is essential to the collaboration required within complex buildings, and to the coordination and fabrication of their cladding systems.

Where 20th-century towers tended towards Figure 11. The Poly International Plaza, Beijing, employs Figure 12. The tubular steel diagrid sits elegantly behind repetitive planning that aligned with the a diagrid system using concrete-filled tubes that vary in the sleek glazed exterior of Guangzhou IFC. The toroidal technical limitations of drawing and structural diameter and thickness from 1.3 m, 50 mm thickness geometry of the gently curved tower was made possible design of the time, contemporary towers can at the base to 0.7 m, 20 mm thickness at the top. only through the use of advanced computer systems. Alternate floors are connected to the diagrid to create © Tansri Muliani exploit the growing digital capabilities and the tensile connections between the nodes. Intermediate floors are hung from the floor above.

CTBUH Journal | 2014 Issue III Architecture/Design | 37 high-performance envelopes are being studied, tested and incorporated into tall buildings. The varied geometries that have become common in new, iconic skyscrapers have resulted in the development of new enclosure systems, which, through digital design and fabrication, have pushed beyond the limits of traditional curtain-wall systems (see Figure 14). Highly efficient, climate-respon- sive façade systems are increasingly being used in contemporary construction, although some tall buildings are still confined to using less complex, shallower systems, due to their lower cost. Floor plate sizes are actually being reduced in order to permit access to views and daylight, with some towers beginning to reintroduce natural ventilation. More advanced, sustainably-motivated towers are incorporating double-façade techniques, although these instances are still somewhat rare. Figure 13. Workers install the glazing that will form the Figure 14. The Shanghai Tower’s double façade system double façade system on the Poly International Plaza. adds a lightness and complexity of geometry through The coordination of such complex geometries is possible its structural layering. © Tansri Muliani only through the advancements of BIM systems. Creating a Vital Urban Future important lessons that need to inform the One of the preoccupations of our impression Although many visionary skyscraper designs positioning of tower types in order to allow of the skyscraper as an urban type is its purportedly support a sustainable agenda, few solar access in cold climates and provide reading as part of the skyline. While skylines choose to tackle the difficulty of the impact of shade in hot ones. Dense urban environments might be important indicators of the tall towers on the increasingly dense urban will also modify the wind regime, which can character and identity of a city, they do environment. This increase in density is result in spaces that can be either too windy detract from the more important detailing of inevitable and desirable as a means to preserve or stagnant. The nature and width of the the engagement of dense buildings with the agricultural land and limit urban sprawl. roadways adjacent to towers will impact the streetscape. Concurrently, much design effort However, not all density is supportive of a rich viability of street life. Car-oriented cities and is expended on detailing the silhouette and urban life. Beyond issues of the relationship elevated roadways adjacent to towers can the “vanity top” of the tower. The images of between the height of inhabitation and its serve to negate their connection to Shanghai (see Figures 15 and 16) highlight relationship to the landscape, described as pedestrian life. Visions of density often deny other issues associated with increased urban “Biophilia” (Wilson 1986), the height and the realities of density. density, such as pollution and air quality, spacing of buildings impacts the climatic which become necessary to discuss when condition at grade. There are extremely looking at the relationship between tall

Figure 15. A view of the skyline of Shanghai from The Bund. © Tansri Muliani Figure 16. The perceived density presented by the skyline denies the significant impact of the car-oriented spaces that separate the buildings in Shanghai’s Pudong District.

38 | Architecture/Design CTBUH Journal | 2014 Issue III buildings, urban density, sustainability and livable cities. Natural ventilation strategies are not “automatic;” they require some desire to open the windows.

When examining urban issues, there is nothing inherently wrong or right about “iconic-looking towers.” In dense urban situations, the pedestrian precinct is mostly influenced by the bottom levels of towers, so if the cladding or form of the overall tower is innovative or banal, Figure 17. Hong Kong is perceived as the exemplar of a life-filled city. However, the streets of Hong Kong are not it does not necessarily influence the vitality of necessary all bustling. the urban space – if the grade condition supports urban activity. It is not the tower itself, that tower design is no longer limited to a References/Further Reading but rather its position and condition at street directed corporate exercise in efficiency that boake, t. m. 2012. CISC Guide for Specifying Architecturally level, that either supports or degrades the advocates repeated floor plans and limited Exposed Structural Steel. Markham: Canadian Institute of Steel Construction. pedestrian realm (see Figures 17, 18, and 19). variations in cladding design. This new urban There are many highly vibrant cities that feature fabric needs to be re-engaged more broadly by boake, t. m. 2014. Diagrid Structures: Systems/ towers in dense configurations. Although there the architectural profession, as we gain the Connections/Details. Basel: Birkhauser. are some instances of extensive podium means to close the gap between open-ended boake, t. m. 2011. Understanding Steel Design. Basel: structures that cause the towers to be set back digital speculation and the realities and Birkhauser. from the street edges, towers in the most potential of actual construction. There are Wilson, E. 1986. Biophilia. Boston: Harvard University vibrant cities tend to directly engage the many topics and areas of discovery that Press. streetscape. This creates a direct connection deserve investigation, and that can be used to between the occupants of the tower and life propel tall buildings into the future in very on the street. These important issues of street compelling ways. Current tall building level concerns also tend not to be addressed in technologies are poised to support explora- fantasy proposals for tall buildings. tions in typological studies, the technical aspects of construction, façade design, sustainable design as well as urban design. This Going Forward power needs to be used to build sensitive tall buildings that build on the valuable lessons Terri Meyer Boake will be a panelist in the The tall building typology has evolved learned. Perhaps the gap between reality and Shanghai Conference Panel Discussion 4: Measuring Tall Buildings: Has CTBUH Got dramatically as a result of innovation in fantasy need not be that large.  it's Height Criteria Correct?, Thursday, 18th construction techniques, a drive to increase September, 1:45 –3.15 p.m. urban density and digital explorations. Unless otherwise noted, all photography credits in Ongoing developments in Asia clearly show us this paper are to Terri Meyer Boake

Figure 18 The Causeway Bay area of Hong Kong has very few “iconic” tall buildings, but Figure 19. The new International Commerce Center in Hong Kong is not located in a is kept alive with intense retail. retail district. Even the glazed nature of its base condition cannot create street life.

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