CTBUH Journal Construction, and Operation of Tall Buildings and International Journal on Tall Buildings and Urban Habitat Future Cities
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About the Council The Council on Tall Buildings and Urban Habitat (CTBUH) is the world’s leading resource for professionals focused on the inception, design, CTBUH Journal construction, and operation of tall buildings and International Journal on Tall Buildings and Urban Habitat future cities. Founded in 1969 and headquartered at Chicago’s historic Monroe Building, the CTBUH is a Tall buildings: design, construction, and operation | 2017 Issue III not-for-profi t organization with an Asia Headquaters offi ce at Tongji University, Shanghai, a Research Special Issue: Women in the Tall Building Industry Offi ce at Iuav University, Venice, Italy, and an Academic Offi ce at the Illinois Institute of Technology, Chicago. CTBUH facilitates the exchange of the latest knowledge available on tall buildings around the world through publications, research, events, working groups, web resources, and its extensive network of international representatives. The Council’s research department is spearheading the investigation of the next generation of tall buildings by aiding original research on sustainability and key development issues. The Council’s free database on tall buildings, The Skyscraper Center, is updated daily with detailed information, images, data, and news. The CTBUH also developed the international standards for measuring tall building height and is recognized as the arbiter for bestowing such designations as “The World’s Tallest Building.” CTBUH Headquarters 104 South Michigan Avenue, Suite 620 Chicago, IL 60603, USA Phone: +1 (312) 283-5599 Email: [email protected] www.ctbuh.org www.skyscrapercenter.com CTBUH Asia Headquarters College of Architecture and Urban Planning (CAUP) Tongji University 1239 Si Ping Road, Yangpu District Shanghai 200092, China Phone: +86 21 65982972 Email: [email protected] CTBUH Research Offi ce Iuav University of Venice Dorsoduro 2006 30123 Venice, Italy Phone: +39 041 257 1276 Email: [email protected] CTBUH Academic Offi ce S. R. Crown Hall Illinois Institute of Technology 3360 South State Street Chicago, IL 60616 Phone: +1 (312) 567 3487 Email: [email protected] ISSN: 1946 - 1186 Inside News and Events Features 20 Structural Engineering Frontiers in High-Rise Outrigger Design Abstract CTBUH Technical The Council on Tall Building and Urban Habitat’s Outrigger Working Group has addressed the pressing need for design guidelines for outrigger systems CTBUH Technical Guides with this guide, now in its second edition, providing a comprehensive Guides overview of the use of outriggers in skyscrapers. This guide offers detailed In 2012, CTBUH published the first Outriggerrecommendations for analysis of outriggers within theDesign lateral load resisting for Edition 2nd Buildings High-Rise for Design Outrigger systems of tall buildings, for recognizing and addressing effects on building behavior and for practical design solutions. It also highlights concerns specific to the outrigger structural system such as differential column shortening and construction sequence impacts. In this edition, a new chapter explores the use of “hybrid” outrigger systems that can “tune” the stiffness of outrigger trusses, use leverage of the outrigger arms to drive non-linear damping High-Rise Buildings Technical Guide.devices, and use “yielding”In materials 2016, that absorb seismic energy. the CTBUH Several project examples are explored in depth, illustrating the role of outrigger systems in tall building designs and providing ideas for future projects. The guide details the impact of outrigger systems on tall building designs, and demonstrates ways in which the technology is continuously advancing to improve the efficiency and stability of tall buildings around the Outrigger Working Group felt it wouldworld. The new second be edition features beneficial updated design considerations to to reflect current practices, Expanded systems organization and examples, and 02 This Issue 52 Tall Buildings in Numbers updated recommendations and suggestions for future research. Hi Sun Choi is a Senior Principal at Thornton Tomasetti with over 20 years of experience in structural analysis, investigation, design, and review of a variety update the design guide with variationsof building types, including commercial of and residential outrigger buildings. Dr. Goman Ho is an Arup Fellow with more than 25 years working experience. He has been significantly involved in a large number of tall buildings, from analysis, design to construction, focusing his research on stability and nonlinear transient analysis. Leonard Joseph, principal at Thornton Tomasetti, has analyzed, designed, (cm) displacement Lateral systems and tall building projects andthat reviewed high-rise buildings, have sports facilities, hangars, hotels, been historic newly buildings, manufacturing facilities, and parking garages around the world. Neville Mathias, Associate Director and Senior Structural Engineer at Skidmore, Owings & Merrill, specializing in performance-based seismic design, Hi Sun Choi Leonard M. Joseph proposed or successfully implementedhas worked extensively on major since buildings around the world for overthat 30 years. time. Outrigger Design for The Working Group reached out to colleagues to collect High-Rise Buildings An output of the CTBUH Outrigger Working Group Ilkay Can-Standard, Vertical Transportation: Outrigger2ndEdition_Cover_mockup.indd 1 2nd Edition information on recently developed outrigger systems Hi Sun Choi, Goman Ho, Leonard Joseph & Neville Mathias Tilted angle and real project examples that demonstrate their Figure 1. Tilted 60-story study structures with outriggers and tilt angles of 0, 4, 7, 9, and Figure 2. Lateral displacements of 60-story tilted outrigger structures with tilt 13 degrees showing exaggerated gravity deformations. Source: Moon 2016 angles of 0, 4, 7, 9, and 13 degrees . Source: Moon 2016 viability and value. The second edition of the guide, 2/20/2017 10:00:44 AM outrigger arms projecting from a building columns in tall structures can be leveraged to A damped outrigger system disengages the published recently in 2017, includes innovative approaches to Co-chair CTBUH New Ascent & Acceleration core to efficiently drive nonlinear damping yield supplemental damping by introducing outrigger elements (reinforced concrete walls address previously recognized design concerns and limitations. It also includes devices. The resulting supplementary vertically mounted dampers between the or steel trusses cantilevered from the core) SawTeen See Rupa Garai more project examples with new approaches to optimize building performance damping can significantly reduce tall building outrigger ends and the perimeter column from the floor framing at their top and bottom through dampers incorporated within outrigger systems. This paper summarizes accelerations, deformations, and forces from (Smith and Willford 2007). These movements edges and from the perimeter columns. This Authors the major updates of the second edition and highlights several projects of vortex-induced oscillations (VIO) in wind, or are proportional to the lateral drift of the makes it possible to generate relative vertical Hi Sun Choi, Senior Principal reduce building deformations and structural structure and can typically be of relatively movements between the outrigger ends and York Young Professionals Thornton Tomasetti significance to the contemporary discussion of outrigger technology. 51 Madison Avenue demands in earthquakes. Supplementary small magnitude, particularly in wind events. the adjacent perimeter columns when a New York, NY 10010, United States Keywords: Outriggers, Structural Engineering, Wind, Seismic damping can take the form of viscous Mechanisms can be utilized to amplify these structure is subjected to seismic and wind t: +1 917 661 7878 f: +1 917 661 7801 dampers, viscoelastic dampers, tuned mass relatively small vertical movements to loads; the drift displacements/velocities can e: [email protected] Design Considerations for Outriggers occurs between outrigger levels (see Figures 1 dampers (TMDs), tuned liquid column potentially increase supplementary damping. be captured to generate supplementary www.thorntontomasetti.com Committee 54 Talking Tall: Jeanne Gang Supporting Complex Forms and 2). dampers (TLCDs), or sloshing dampers. But A concept for one such mechanism – where damping. To increase the efficacy of a Leonard M. Joseph, Principal mechanically damped outriggers can provide the damper movement and velocity are damped outrigger system and create large Thornton Tomasetti “Stiffness Effects from Overall Systems” is a The effect of building taper is also discussed. supplementary damping contributions amplified, thus increasing the supplemental velocities that would generate increased 707 Wilshire Boulevard, Suite 4450 Los Angeles, CA 90017, United States newly added section of the Technical Guide, For a building that tapers narrower with comparable to a TMD or TLCD without the damping in the structure – was described by damping, the use of a mechanism has been t: +1 949 271 3320 which discusses outrigger interactions with height, compared to a straight building of the attendant space, weight, or tuning Mathias et al. (2016). proposed (see Figure 3). The geometric f: +1 949 271 3301 Birds, Planes and Bio-Blitzes www.thorntontomasetti.com complex architectural forms such as twisted, same total floor area, there are smaller wind requirements. tilted, and tapered shapes, now common and seismic loads imposing on the building SawTeen See, Managing