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A U S T R A L I A S Q U A R E

ST R UCT URAL T YPOLOGY 50 stories lightweight concrete building 42 m diameter with a clear span of 11 m from core to perimiter.

26 4 Geo rg e S t , Syd ne y

Polygonal made up of 20 segments giving the appearance of a round building.

Archite c t Harr y S ei d l er Comple tion D a t e 1961 - 1967 Predomi n a n t U s e C ommerci al O ffi c e S p a c e

Braced Frames

Tube Structures

Tube - in - Tube Structures

Diagrid Structures

Trussed Tubes

Bundled Tubes

Space Truss

Megaframe Structures

FIG. 2

Basic Principle of High Rise Structure

Typology

Individual members and the overall structure must be designed for:

• A framed tube structure utilizes the entire perimeter to resist lateral loads.

• adequate strength under gravity and lateral loads. • enough stiffness built into structure to resist deflections to acceptable levels

• Viewed as a hollow, cantilevered beam, fixed at the ground level, with exterior frames constructed of closely spaced columns rigidly connected to deep spandrel beams. • Eliminates the structural need for other interior walls/bracing.

Tube-in-Tube Structure Combination of: Interior structure: rigid frame through shear walls acting as structural tube. Exterior structure: lateral force resisting ele ments located along perimeter of structure.

• Circular shape means even distribution of lateral loads (whereas rectangular means more pressure on corners) • The radial beams tie the exterior and interior tubes together, allowing the two tubes to resist lateral forces as a unit. • The exterior tube can resist the overturning forces efficiently, with its larger plan dimensions, but the openings compromise its ability to resist shear. The solidity of the inner tube can resist shear.

FIG. 1

University of South Australia, B.Arch. St, BUILD2006, Assignment 1, 2010. Research Topic: Structure and Core Student Details: BADGERY_J. Id 100110419, BERRYMAN_J. Id 100041031, COLLINS-MCBRIDE_M. Id 100084912


1

VERT I C A L L O A D PATH S GR AV I T Y L O ADS

Vertical Components

Columns, core shafts and bearings walls. Column sizes increase progressively toward the base of the building due to the accumulated increase in gravity loads transmitted from the floors above.

Atria or Voids

There are no significant atria or voids.

2

Horizontal Components

Radial Beams the spanning members of the roof and floor systems help tie the vertical structure together, serving as horizontal diaphragms. Long span beams gather the gravity loads and redirect/transmit them to large exterior columns or to the interior core for distribution to the foundation. Beams and column sizes are large but fewer are used.

FIG. 3

1

2

FIG. 4

University of South Australia, B.Arch. St, BUILD2006, Assignment 1, 2010. Research Topic: Structure and Core Student Details: BADGERY_J. Id 100110419, BERRYMAN_J. Id 100041031, COLLINS-MCBRIDE_M. Id 100084912


LAT E R A L S TA B IL I TY Exterior structure the circular form of the tower is most efficient in resisting horizontal wind loads. Interior structure the two tubes of concrete lift shafts, braced by division walls between lifts, provide great rigidity and wind resisting stiffness to the tower.

FIG. 6

Lateral loads from winds and earthquakes are distributed to each of the floor or diaphragm levels. at each, there must be a number of braced or shear walls to transfer the cumulative lateral shear forces from the diaphragms above.

FIG. 5 FIG. 7

Inherently stable plan configurations for torsional resistance. torsional resistance is enhanced by configuring rigid frames into a complete tube. longer larger beams make a stronger floor and can also make appropriate contribution to resisting lateral shear forces.

University of South Australia, B.Arch. St, BUILD2006, Assignment 1, 2010. Research Topic: Structure and Core Student Details: BADGERY_J. Id 100110419, BERRYMAN_J. Id 100041031, COLLINS-MCBRIDE_M. Id 100084912


C O M P ON E N T S

COR E T YPOLOGY

Mass production: every elevator shaft, radial beam, column is identical.

SINGLE CENTRAL CIRCULAR CORE TYPOLOGY

VERTICAL STRUCTURE: COLUMNS

• Single core maximises unobstructed leasable area

20 projecting vertical columns tapering to the summit.

• Central locations are ideal for symmetrical designs:

Projecting columns around the perimeter diminish in size as the building rises, to accommodate the need for stronger support at the base due to cumulative effect of gravity loads.

allow for short horizontal runs and efficient FIG. 8

distribution patterns. • Does not take up any daylight perimeter. • Flexibility of use/layout

FIG. 9

HORIZONTAL FLOOR STRUCTURE

INTERLOCKING RIB REINFORCEMENT

Beams, spans, radial beams: 520mm deep

Combination of interlocking rib reinforcement and radial support beams

From the core divisions, tapered radial beams span to the 20 external columns which project from the facade.(like spokes in wheel) Clear span of 11m from core to perimeter all around.

Concrete ribbing system applied to the two lower floors. Interlocking curved ribs takes heavy load from upper floors. In curvature, taper and variation in width, the ribs follow the stress conditions in the floors.

FIG. 11

FIG. 10

University of South Australia, B.Arch. St, BUILD2006, Assignment 1, 2010. Research Topic: Structure and Core Student Details: BADGERY_J. Id 100110419, BERRYMAN_J. Id 100041031, COLLINS-MCBRIDE_M. Id 100084912


VE RT I C A L C I R C ULATION FUNCTION

Cores generally comprise of a consolidation of shafts for mechanical services, makes for easy access for alterations or maintenance, exit stairways, elevators, plumbing, electrical, data and comms etc

Parking Entrance Lobby Typical Office Floors Mechanical Floors Restaurant Observation Deck Fire stairs Lifts

THIS

CORE CONTAINS: • Two interlocking scissor-type fire stairs. • Air-conditioning ducts and service risers • Goods lift. • Male and Female Amenities

LIFT / LOBBY CONFIGURATION 4 Low Rise Lifts 5 Medium Rise Lifts 5 High Rise Lifts 2 Express Lifts 1 Goods Lift Elevator Lobby Office space: option for subdivision

Surrounding these are 17 passenger lifts, within an inner and outer concrete shaft, extending full height of the tower.

FIG. 13

FIRE STAIRS There are three points of access to the fire stairs at each floor level, with the maximum journey from floorplate to stair approximately 20m. FIG. 12

Fire stairs are interlocking, providing optimal egress in emergency. The points of egress from the ground floor lead directly to the large plaza area.

FIG. 14

University of South Australia, B.Arch. St, BUILD2006, Assignment 1, 2010. Research Topic: Structure and Core Student Details: BADGERY_J. Id 100110419, BERRYMAN_J. Id 100041031, COLLINS-MCBRIDE_M. Id 100084912


EF F ECT ON DE S I GN SUBDIVISIBILITY Net usable area has a clear span from core to perimeter all the way around, allowing flexibility of function and fitout.

EXPRESSION/CONCEALMENT OF STRUCTURE Structurally expressive ceilings: IMPLICATION ON FLOOR SPACE Gross to Net ratio is 80:20. (usable floor space to service floor ratio)

The floor structure of curved concrete ribs is expressed in the ceilings of the floor below, which is aesthetically beautiful.

EFFECT ON FACADES Columns are expressed on the exterior, tapering towards the sky. They also provide some element of horizontal shading as the protrude concrete structure with quartz faced pre-cast facade.

Simple method of partitioning for subdivions: arranged on modular subdivisions of both radial and circumferential lines. Ceiling of the lobby is formed by the ribbed floor system used for the first two floors of the tower.

ACCESS TO LIGHT/VIEWS Circular form creates more desirable space relationships toward adjacent properties and allows a maximum of light into the surrounding streets. Wide open spaces result outside the windows, which only comes close to neighbouring structures at one tangential point. Central core maximises use of perimeter daylight for office spaces. FIG. 15

FIG. 18

FIG. 16

FIG. 17

REF ERENCE LIST Blake, P, 1973 , Architecture for the new world: the work of Harry Seidler , Horwitz , Sydney. FIG 1, 3, 15, 16, 17, 18 Frampton, K & Drew, P, 1992 , Harry Seidler: four decades of architecture , Thames & Hudson, London. FIG 5, 8, 9, 10 Seidler, H, 1997 , Harry Seidler: selected and current works , Images Publishing , Mulgrave, Vic. FIG 4, 13 Harry Seidler & Associates 2010, Australia Square, accessed 07/08/2010 <www.seidler.net.au> Australia Square 2010, Australia Square, accessed August 2010 <www.australiaquare.net> Ching, F & Onouye, B, 2009 , Building structures illustrated , John Wiley & Sons, Hoboken, N.J. FIG 2, 6, 7, 11

Revolving Resturant

Figures 8, 12 and 14 have been generated by the authors. University of South Australia, B.Arch. St, BUILD2006, Assignment 1, 2010. Research Topic: Structure and Core Student Details: BADGERY_J. Id 100110419, BERRYMAN_J. Id 100041031, COLLINS-MCBRIDE_M. Id 100084912


BERJN001_24761_BUIL2006_A1_CENTRAL CORE