Top Tall BuildingsTop Tall Buildings
Top rated tall buildings and its structural system
Presented byPragya N Roy (Peter)Structural EngineerStructural Engineer.
Tall Buildings The tall buildings can be defined as ‘the buildings that are
significantly taller than their surroundings and have a significant impact on the skylineimpact on the skyline.
Tall buildings are taller than the overall building height in an area. Which must be considered in relation to their local context.
The important criterion is whether or not the design is influenced by some aspect of ‘tallness’’. Which influences
PlanninggDesignConstructionUseUse
Tall Buildings Criteria
The non-profit international organization Council on Tall The non profit, international organization Council on TallBuildings and Urban Habitat (CTBUH) was formed in 1969 andannounces the title of "The World’s Tallest Building" and setsth t d d b hi h b ildi dthe standards by which buildings are measured.
The council listed and ranked buildings in four categories: The council listed and ranked buildings in four categories:Height of structural or architectural topHeight of highest floorg gHeight to the top of roof Height to top of any part of the building
Top Ten Skyscrapers of the world
Top Ten Skyscrapers of the world
Burj khalifaBurj khalifa General information
B j Kh lif h b th ld' t ll t b ildi• Burj Khalifa has been the world's tallest building since 2010.
• Former/other name(s) : Burj Dubai• Location : Dubai UAE• Location : Dubai, UAE• Status : Complete• Groundbreaking : January 2004• Constructed : 2004 2010• Constructed : 2004–2010• Opening : 4 January 2010• Use : Office /
Residential / HotelResidential / Hotel• Roof : 828 m (2,717 ft)• Top floor : 621.3 m (2,038 ft)• Reason of popularity : Tallest building in• Reason of popularity : Tallest building in
the world.
Burj khalifaBurj khalifa Technical details• Floor count -163 habitable floors plus 46
maintenance levels in the spire and 2 parking p p glevels in the basement.
• Floor area -309,473 m2 (3,331,100 sq ft)• Cost -$1.5 billion C i i l dCompanies involved• Architect(s) -Adrian Smith at SOM• Structural engineer -Bill Baker at SOM• Contractors:Contractors:
-Samsung C&T, Besix and Arabtec,-Supervision Consultant Engineer & Architect of Record Hyder Consulting Construction -Project Manager Turner Construction -Grocon-Planning Bauer AG and Middle East Foundations Lift contractor Otis-Lift contractor Otis
-VT consultant Lerch Bates• Developer -Emaar Properties
Burj Khalifa – Design ConceptStructural System
– The structural system consisted with a Buttressed Core, and highperformance reinforced concrete wall construction. Each of the wingsbuttress the others via a six-sided central core, or hexagonal hub (asshown in figure). Corridor walls extend from the central core to near theend of each wing, terminating in thickened hammer head walls.Perimeter columns and flat plate floor construction complete the systemi i b t l t l l d i ti tgiving a best lateral load resisting system.
The structural system of The Burj Khalifa
Burj Khalifa – Design Concept– At mechanical floors, outrigger walls are provided to link
the perimeter columns to the interior wall system, allowingthe perimeter columns to participate in the lateral loadresistance of the structure.
– Thus all of the vertical concrete is utilized to support both– Thus, all of the vertical concrete is utilized to support bothgravity and lateral loads, so the tower is extremely stifflaterally and torsionally.
– It is also a very efficient structure in that the gravity loadresisting system has been utilized so as to maximize itsuse in resisting lateral loads.use in resisting lateral loads.
– During the design process, engineers rotated the building120 degrees from its original layout to reduce stress from
i dwind.– At its tallest point, the tower sways a total of 1.5 m
Burj Khalifa – Design Concept• Special features:
– The Y-shaped plan is ideal for residential and hotel usage, with the wings allowing maximum outward views and inward natural light.
– Also this shape helps to reduce the wind forces on the tower, as well as to keep the structure simple and better constructability.
– The top of the Tower consists of a structural steel spire enabling the structure to be the tallest in the world, and the entire Tower is founded on a 3700mm thick reinforced concrete pile-supported raft foundation
The piled-raft foundation of Burj Khalifa
Taipei 101 (Taipei)General information Location : Xinyi District, Taipei, Taiwan,
Republic of ChinaRepublic of China Status : Complete Constructed : 1999-2004 Opening : December 31, 2004p g Use : Mixed Use: communication,
Conference, Fitness center, Library, Observation, Office, Restaurant, RetailRestaurant, Retail
Height Antenna or spire : 509.2 m (1,670.6 ft) Roof : 449.2 m (1,473.8 ft) Top floor : 439.2 m (1,440.9 ft)
Taipei 101 (Taipei)Technical detailsFloor count : 101 (5 basement floors)Floor area : 412,500 m2 (4,440,100 sq ft), ( , , q )Elevators : 61 Toshiba/KONE elevators, including double-deck shuttles and 2 high speed observatory elevators)Cost : NT$ 58 billion (USD $ 1.80 billion)Floors below ground : 5Elevators : 61Elevators : 61Top elevator speed : 16.8 m/sParking spaces : 1839Companies involvedArchitect(s) : C.Y. Lee & partnersStructural engineer : Thornton Tomasetti at Evergreen
EngineeringOwner/Developer : Taipei Financial Center CorporationManagement : Urban Retail Properties Co.MEP Engineer : Continental Engineering Consultants IncMEP Engineer : Continental Engineering Consultants, Inc.contractors : Kumagai Gumi
: Taiwan Kumagai: RSEA Engineering: Ta-You-Wei Construction
S C: Samsung Engineering and ConstructionElevator company : Toshiba Elevator and Building Systems
Corporation (TELC)Wind consultant : RWDI
Taipei 101 –Design ConceptStructural system ( gravity & lateral loads)
Structural system is a Braced core with belt trusses.
Gravity loads are carried vertically by a variety of columns withinthe core and the perimeter. Slabs are composite in nature andare typically 135 mms thick.yp y
Lateral loads are resisted by a combination of braced cores,t i t t th l i th b ildi ' toutrigger trusses connect the columns in the building's core to
those on the exterior, the super columns in the outer perimeterand the Special moment resisting frame (SMRF).
Taipei 101 –Design Concept• For additional core stiffness, in addition to diagonal braces, concrete
shear walls are casted between core columns from basement to the 8th floor. Outrigger trusses occur at 11 levels of the structure some are two storey height and others are single storey height. In each of such floor 16 outriggers present.
Plan of the structural system which shows the braced core and the outer perimeter columns
Taipei 101 –Design ConceptOther important information
Designed to withstand the typhoon winds and– Designed to withstand the typhoon winds and earthquake which is common in its area of the Asia-Pacific.
– Designed to withstand winds of 60 m/s and the strongest earthquakes likely to occur in a 2,500 year cyclecycle.
– Double-pane windows blocking external heat by 50% and recycled water meeting 20-30% of the building's needs
– Currently under way to make Taipei 101 "the world's tallest green building" by LEED standardstallest green building by LEED standards
Shanghai World Financial CenterGeneral information• Location : 100 Century
Avenue PudongAvenue, Pudong, Shanghai, China
• Status : Complete• Status : Complete• Constructed : 1997 – 2008• Use : Office, Hotel,
Museum,Museum, Observation, Parking Garage, Retail
Height• Antenna or spire : 494.4 m / 492 m • Roof : 487.4 m • Top floor : 474 m
Shanghai World Financial CenterTechnical details• Floor count : 101• Floor area : 381,600 m2 • Cost : RMB ¥ 8.17billion
(US $1.20billion)Companies involved• Architect(s) : Kohn Pedersen Fox• Structural engineer : Leslie E. Robertson
A i t RLLPAssociates RLLP• Developer : Mori Building Co.• MEP Engineer: Kenchiku Setubi Sekkei
KenkyushoKenkyusho• Main contractor : China State Construction• Main contractor : Shanghai Construction• Elevator company: Otis Elevator Company• Elevator company: Otis Elevator Company
Shanghai World Financial Center-Design ConceptpStructural system (for gravity and lateral loads) Concrete shear walls of the service core together with Concrete shear walls of the service core together with
Major columns, Diagonals and belt trusses in outer frameis the lateral force resisting system.
Thi t f h l t d th thi k f th This outer frame helps to decrease the thickness of theshear walls of services core as well as a decrease in theweight of structural steel in the perimeter walls whileg pmaintaining a good structural stability in lateral loadresisting.
Further by making use of outrigger trusses coupled to Further, by making use of outrigger trusses coupled tothe columns of the mega-structure, a further reduction ofshear walls were realized
Shanghai World Financial Center-Design Conceptp
Structural system
Shanghai World Financial Center-Design ConceptConcept
• Special features :– The diagonals of the mega-
t t f d f ld dstructure are formed of weldedboxes of structural steel. Thesesteel boxes are in-filled withconcrete thus providingconcrete, thus providingincreased stiffness, non-linearstructural behaviour, andstructural damping.structural damping.
– As well, in the upper reaches ofthe building enhanced withthe building, enhanced withstud shear connectors, theconcrete is used to stabilizeagainst buckling the thin steelagainst buckling the thin steelplates of the diagonals
Connection of Diagonals to Mega Columns
International Commerce Centre
General information• Location : Hong Kongg g• Status : Complete• Groundbreaking: 2002• Constructed : 2002-2010• Constructed : 2002-2010• Opening : 2010• Use : Hotel, Observation,
Office Parking garage RetailOffice, Parking garage, Retail
Height• Roof : 484 m (1,587.9 ft)• Top floor : 476 m (1,561.7 ft)
International Commerce CentreTechnical details• Floor count : 108• Floor area : 262 176 m2 (2 822 039 sq ft)• Floor area : 262,176 m2 (2,822,039 sq ft)
• Companies involved• Architect(s) : Architect Wong & Ouyang• Architect(s) : Architect Wong & Ouyang
(HK) Ltd.• Design Architect : Kohn Pedersen Fox
Associatesssoc ates• Landscape Architect : Belt Collins & Associates• Structural engineer : Arup at Maunsell AECOM
Group• Developer : Sun Hung Kai Properties ,
Hang Lung Group• Management : Kai Shing Management
Services Limited• Wind consultant : RWDI
International Commerce Centre(Design Concept)Concept)
Structural system (for gravity and lateral loads)y ( g y )– General composite frame structure is used for the
tower up to 100/F, with the central core, an external steel frame rested onto 8 mega columns which spansteel frame rested onto 8 mega columns which span about 16m.
– Four sets of outrigger are provided at 6/F, 42/F, 78/F gg p , ,and 100/F. Except for the one on 6/F which is constructed in insitu prestressed design, the upper ones are in fabricated structural steel with an innerones are in fabricated structural steel with an inner frame embedded in the core wall.
International Commerce Centre(Design Concept)Concept)
Outriggers Distributionoutrigger member in initial connected position before final adjustment and welding
Petronas Tower 1 & 2• Former/other name(s): Menara PetronasGeneral information• Location : Jalan Ampang Kuala Lumpur Malaysia• Location : Jalan Ampang ,Kuala Lumpur, Malaysia• Status : Complete• Constructed: 1992 - 1998• Use : Commercial officesHeight• Antenna or spire : 451.9 m (1,483 ft)• Roof : 378.6 m (1,242 ft)
f ( f )• Top floor : 375 m (1,230 ft)Technical details• Floor count : 88• Floor area : 395 000 m2 (4 252 000 sqFloor area : 395,000 m2 (4,252,000 sq
ft)• Elevators : 78• Cost : US$1.6 billion• elevators : 39• top elevator speed: 7 m/s
Petronas Tower 1 & 2
Companies involved• Architect(s) : César Pelli & Associates
St t l i Th t T tti• Structural engineer : Thornton Tomasetti , Ranhill Bersekutu
• Developer : KLCC Holdings Sdn Bhd• Owner : KLCC Holdings Sdn Bhdg• MEP Engineer : WSP Flack + Kurtz• Main contractor : MMC Engineering &
Construction Co.M i t t H H C t ti• Main contractor : Ho Hup Construction
Sdn. Bhd.• Main contractor : Hazama Corporation• Main contractor : J.A. Jones Construction
Co.• Main contractor : Mitsubishi Corporation• elevator company : Otis Elevator Company
i d lt t RWDI• wind consultant : RWDI
Petronas Tower 1 & 2 -DesignConceptConcept• Structural System (for gravity and lateral loads) :
– Structural system consists with 75-by-75-foot concrete cores and anStructural system consists with 75 by 75 foot concrete cores and anouter ring of widely-spaced super columns.
– The core structure of each of the towers is composed of a ring of– The core structure of each of the towers is composed of a ring ofsixteen cylindrical columns of high strength reinforced concrete.
The columns vary in size from 2 4 meters in diameter at the lower– The columns vary in size from 2.4 meters in diameter at the lowerareas to 1.2 meters in diameter at the top, and are placed at theoutside corners.
– The columns are linked with a series of concrete core walls and ringbeams. These movement-resistant and damper-free structures canbe described as a pair of “soft tubes” There are actually twobe described as a pair of soft tubes . There are actually twoconcentric pressurized cores in the structures, and the two coresunite at the 38th floor of each tower.
Petronas Tower 1 & 2 -Design ConceptConcept
Petronas Tower 1 & 2 -Design ConceptConcept
Petronas Tower 1 & 2 -Design ConceptConcept
Petronas Tower 1 & 2 -Design ConceptConcept
The Sky Bridge Dimesions
• Center line Span 191 feet• Center line Span - 191 feet• Overall Width - 17 feet • Overall Height - 31 feet• Length of Supports - 169 feetg pp• Total Weight - 720 tons
Willis Tower (Chicago)Former/other name(s) - Sears TowerGeneral information
L ti 233 S W k D i Chi• Location - 233 S. Wacker Drive,Chicago, Illinois 60606 ,United States
• Constructed - 1970-1973• Use Office observation communication• Use -Office, observation, communicationHeight• Antenna or spire -1,730 feet (527 m)
Roof 1 451 ft (442 m)• Roof -1,451 ft (442 m)Technical details• Floor count -108
Fl 4 56 illi ft• Floor area -4.56 million sq ft• Elevators -104, with 16 double-decker• Companies involved
A hit t( ) Skid O i d M ill• Architect(s) -Skidmore, Owings and Merrill• Structural Designer - Dennis Skidmore,
Owings and Merrill (Fazlur Rahman Khan)•
Willis Tower (Chicago)-Design ConceptConcept
Structural system (for gravity and lateral loads) :C i t ith ld d t l f ( ) f ti l– Consists with welded steel frames(square) form verticaltubes that provide the rigidity needed to limit the lateral swayfrom wind forces.
– Bundled framed tubes are a development of the framed tubesystem pioneered by the legendary Fazlur Rahman Kahnwas the first engineer to introduce the notion of shiftingwas the first engineer to introduce the notion of shiftinggravity-load columns from the interior to the perimeter of abuilding.
– The Willis Tower use Bundled tube Instead of one tube, abuilding consists of several tubes tied together to resist thelateral forces Such buildings have interior columns alonglateral forces. Such buildings have interior columns alongthe perimeters of the tubes when they fall within the buildingenvelope.
Willis Tower (Chicago)-Design ConceptConcept
– All nine tubes would rise up to the 50th floor of thepbuilding. At the 50th floor, the northwest andsoutheast tubes end, forming the first step back andthe remaining seven continue up At the 66th floor thethe remaining seven continue up. At the 66th floor, thenortheast and the southwest tubes end. At the 90thfloor, the north, east, and south tubes end. The
i i t d t t b ti t thremaining west and center tubes continue up to the108th floor.
Plan geometries
Nanjing Greenland Financial Center (Nanjing)(Nanjing)
General information• Location : Nanjing , China• Status : CompleteStatus : Complete• Constructed : 2005-2010• Opening : 2010• Use : Hotel / OfficeHeight• Antenna or spire: 450 m (1,480 ft)• Roof : 381 m (1,250 ft)
T fl 339 (1 112 ft)• Top floor : 339 m (1,112 ft)Technical details• Floor count : 89 (2 basement floors)• floors below ground: 5floors below ground: 5• elevators : 54• office space : 64,541 m² / 694,714 ft²• hotel rooms : 450
Nanjing Greenland Financial Center (Nanjing)(Nanjing)
Companies involved
A hit t( ) Ad i S ith t• Architect(s) : Adrian Smith at Skidmore Owings & Merrill
• Associate architect : ECADI• Structural engineer :Skidmore Owings & Merrill• Structural engineer :Skidmore Owings & Merrill• Project developer : Nanjing Guzzi
Greenland Financial Center• Owner / developer : Nanjing State OwnedOwner / developer : Nanjing State Owned
Assets• MEP Engineer : Skidmore Owings &
Merrill• Main contractor : Shanghai Construction• Elevator company : Schindler
Nanjing Greenland Financial Center –Design ConceptDesign Concept
Structural system (for gravity and lateral loads) : The gravity load-resisting structural system consists ofg y g y
structural steel floor framing supporting a 155mm thickcomposite metal deck floor slab. Floor framing inside the"super core" consists of reinforced concrete beamssuper-core consists of reinforced concrete beamssupporting a reinforced concrete one-way slab.
The central reinforced concrete "super core" and the exteriorpcomposite columns then transmit the floor framing loads tothe foundations.
The closed form of the "super core’s" perimeter provides a The closed form of the super-core s perimeter provides alarge amount of the overall torsional stiffness of the building.The core wall thicknesses were optimized in order to betterbalance the triangular-shaped core for both bending stiffnessand torsional rigidity.
Nanjing Greenland Financial Center –Design ConceptDesign Concept The primary lateral load resisting system is comprised of
an interior reinforced concrete “super-core” shear wallan interior reinforced concrete super core shear wallsystem and exterior composite columns.
The secondary lateral system for the Main Towerconsists of a moment-resisting frame at the perimeter ofthe building.
The perimeter moment frame system provides additional The perimeter moment frame system provides additionaltorsional stiffness, structural integrity, and redundancy forthe overall building.
The tower’s shape is also highly functional- its triangularform relates to shape and size of the site whilemaximizing views of the mountains, lake and historicmaximizing views of the mountains, lake and historicNanjing buildings
Outrigger and Belt Truss configuration
Lateral Load resisting system
Guangzhou West TowerGuangzhou International Finance CentreGeneral information• Location : Guangzhou China• Location : Guangzhou, China• Status : Complete• Groundbreaking : December 2005• Constructed : 2010• Opening : 2010• Use : Hotel / OfficeHeight• Antenna or spire: 440.2 m (1,444 ft)• Roof : 437.5 m (1,435 ft)• Top floor : 432 m (1,417.3 ft)• Technical details• Technical details• Floor count : 103 (4 basement floors)• Floor area : 285,000 m2 (3,068,000 sq ft)• top elevator speed: 8 m/sp p• hotel rooms : 374
Guangzhou West Tower
Companies involved
• Architect(s): Wilkinson Eyre
• Associate architect: South China Design Institute
• Structural engineer : Arup• Structural engineer : Arup• MEP Engineer : Arup• Elevator company : Otis
El t CElevator Company
Guangzhou West Tower-Design Concept
Structural Plan of Guangzhou West Tower
• The design integrates structural systems, in both steel and structural concrete tosupport the curving shape of the building, as well as the wind and seismic loadsimposed on the tower. This is one structural innovation is integrated wind turbines.
Structural Plan of Guangzhou West Tower
p gThese turbines, which are fed from funnel-like openings in the facade, are supportedon floor slabs occurring within the opening zones and are laterally braced against thefloor above.
Jin Mao Tower (Shanghai)Jin Mao Tower from nearby Shanghai World Financial CentreGeneral information• Location : 88 Century Avenue, PudongLocation : 88 Century Avenue, Pudong
District, Shanghai 200121, China• Status : Complete• Constructed : 1994 - 1999
U Offi H l• Use : Office, Hotel, Observation, Retail
Height• Antenna or spire: 421 m / 1,380 ftp ,• Roof : 370.0 m / 1,214 ft• Top floor : 366.0 m / 1,201 ftTechnical details• Floor count : 88• Floor area : 278,707 m²• Elevators : 61• floors below ground: 3• floors below ground: 3• elevators : 130• top elevator speed: 9 m/s
Jin Mao Tower (Shanghai)Companies involved
A hit t( ) Ad i S ith t Skid• Architect(s) : Adrian Smith at Skidmore Owings & Merrill
• project developer: China Shanghai Foreign Trade CentreTrade Centre
• structural engineer: Skidmore Owings & Merrill
• MEP Engineer: Skidmore Owings & g gMerrill
• main contractor: Shanghai Jin Mao Contractor
• elevator company: Mitsubishi Elevator and Escalator
• wind consultant: Alan G. Davenport Wind Engineering GroupEngineering Group BLWTL
Jin Mao Tower (Shanghai)-Design ConceptConcept
Structural Systemy
The building employs an advanced structural engineeringt f i d d th k i i hi h f tifsystem of wind and earthquake engineering which fortify
it against typhoon winds of up to 200 km/h (with the topswaying by a maximum of 75 cm) and earthquakes of upy g y ) q pto 7 on the Richter scale.
The steel shafts have shear joints that act as shockabsorbers to cushion the lateral forces imposed by windsand quakes, and the swimming pool on the 57th floor isq , g psaid to act as a passive damper.
Jin Mao Tower (Shanghai)-Design ConceptConcept
Gravity loadThe remaining eight composite steel columns ("super-columns" of steel sections filled with high strength concrete. ) are distributed in pairs among the four corners of the building mostly to support the gravity loads from this portion of the floor plates
Lateral loadThe shear walls of an octagonal core. The deflection of the Jin Mao e s ea a s o a oc ago a co e e de ec o o e J aoTower is adequately controlled by a simple but innovative damping system of specially designed shear bolts that move within damping channels. Also, the mass of the 57th floor swimming pool apparently contributes its own damping effect.
Plan geometries
Trump International Hotel and Tower (Chicago)Tower (Chicago)
• Location of Trump Tower along the Chicago RiverGeneral information
L ti 401 N W b h A Chi• Location -401 N. Wabash Ave.,Chicago, Illinois,United States
• Groundbreaking -March 17, 2005• Constructed 2005 2008• Constructed -2005–2008• Opening -January 30, 2008• Use -Hotel, CondominiumHeightHeight• Antenna or spire -1,389 feet (423.4 m)• Roof -1,170 feet (356.6 m)Technical detailsTechnical details• Floor count -98• Floor area -2,600,000 square
feet (242 000 m2)feet (242,000 m2)• Elevators -27, made by Kone• Cost -USD $ 847 million
Trump International Hotel and Tower (Chicago)Tower (Chicago)
Companies involved
• Architect(s) : Adrian Smith at Skidmore Owings & Merrill
• Structural engineer: William F. Baker at Skidmore Owings & Merrill
• Developer : Trump Organization• MEP Engineer : WMA Consulting
EngineersEngineers• Main contractor : Bovis Lend Lease Inc.• Elevator company: KONE• Wind consultant : RWDI
Trump International Hotel and Tower –Design ConceptDesign Concept
Structural system (for gravity and lateral loads):– A core and outrigger system provides lateral stability for the
Trump Tower. Large outrigger elements at the mechanical levels tie the concrete core to perimeter columns, significantly increasing the building’s lateral stiffness as well as its resistanceincreasing the building’s lateral stiffness as well as its resistance to overturning due to wind.
– The core is located at the center of the building and consists of four I-shaped and two C-shaped walls at the base, and gradually reduces to two I-shaped walls above the final setback at level 51. Above the entries to the elevator cores at each level deepAbove the entries to the elevator cores at each level, deep reinforced concrete link beams connect the flanges of adjacent walls.
Trump International Hotel and Tower –Design ConceptDesign Concept
Structural core and column layout at a residential floor
Trump International Hotel and Tower –Design ConceptDesign Concept
– The outriggers are large reinforced concrete wall-beams, that extend from the flanges of the core walls to the exterior columns at three of the double-height mechanical floors in the tower (levels 28-29, 50-51, and 90-91). These outrigger levels occur j st belo the b ilding setbacks and the o triggers also ser e asjust below the building setbacks, and the outriggers also serve as transfer girders as the columns are relocated at the façade.
– Typical residential floors are 9-inch (230-mm) thick flat plates serve as gravity load resisting system together with frame.
– The design of the building incorporates three setback features designed to provide visual continuity with the surrounding skyline
References
• http://en.wikipedia.org/wiki/• http://www.emporis.com• http://www.burjkhalifa.ae/thetower/structure.aspx• http://www.allaboutskyscrapers.com/taipei101.htmhttp://www.allaboutskyscrapers.com/taipei101.htm• http://www.ctbuh.org• http://www.yangsquare.com/petronas-tower-in-detail/
http://www som com/content cfm/burj khalifa• http://www.som.com/content.cfm/burj_khalifa• http://architecture.about.com/od/skyscrapers/a/Worlds-Tallest-
Buildings.htm• www.sefindia.org/rangarajan/Taipie101BuildingAnalysis.pdf• www.ncree.org.tw/iwsccc/PDF/03%20-%20Shieh.pdf• http://skyscraperpage.com/cities/?buildingID=7609• http://www.structuremag.org/article.aspx?articleID=393
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