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The worlds greatest athletes,many of who spent a lifetimepreparing for the moment,

gathered last fall in Sydney, Aus-tralia for the Olympic Games. TheSydney Olympic Committeewanted nothing less than a world-class facility to serve as the stagefor this athletic and cultural specta-cle.

The result was the $200 millionSydney SuperDome, built for thegames but destined to be a key ele-

ment of Sydneys cultural fabric fordecades to come. The grand arena,seating 15,000 for gymnastics and18,000 for basketball, was designedby an international consortium ledby Devine deFlon Yaeger, a KansasCity based architectural and engi-neering firm.

The challenges were many andvaried. The Sydney Olympic Com-mittee set high environmental stan-

dards for the buildings construc-tion and operation. Accessibilityconsiderations were paramount be-cause the SuperDome was alsoused for international Paralympicevents for the disabled, which tookplace only weeks after theOlympics ended.

Construction of major projectsalso pose a unique challenge on theisland continent, which has noglass manufacturing capability andis home to only two construction

cranes capable of handling such aproject.

The goal was to create a newbenchmark in the design of acces-sible and green public assemblyfacilities. To meet that goal and de-liver the building on time and onbudget, the planners decided earlyin the process to depend heavily onstructural steel. Steel is the domi-nant material in the SuperDomes

construction and plays the key rolein achieving the character envi-sioned by the designers. Steels ver-satility has been demonstrated bythe design of this unique structure.

Various simple and complexarch structures and folded platestructures were investigated earlyon but discarded in favor of a trusssystem. During the concept designa number of alternative truss sys-tems were examined, including afully trussed roof, a braced arch

roof and a roof with and withoutthe stepped center hub. The alter-natives included investigation ofboth wood and steel truss systems.The final design evolved in re-sponse to the weight of the struc-ture, erection requirements andenvironmental analysis.

Devine deFlon Yaeger employedsustainable design techniquesthroughout the project and per-

Modern Steel Construction / February 2001

SSYYDDNNEEYY ArenaWins

GOLD Medalby Carl Yaeger

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formed in-depth analysis of se-lected building materials, lookingat the ecology rating of each. Forevery decision, the questions askedwere: Is it recyclable? Is it local? Isit transferable? Is it cost-efficient?The goal was nothing less than to

create the greenest arena facilityin the world.

The building boasts a self-con-tained system to maximize the useof recycled water. With this graywater system, roof runoff and handwater are then used for toilets, etc.The SuperDome also incorporatesthe countrys grandest solar struc-ture and energy-efficient lightingsystem and largely used local laborand indigenous materials.

One percent of total seating ca-

pacity was designated for specta-tors with disabilities and theircompanions. Patrons with disabili-ties benefit from enhanced sightlines and easy access to everythingfrom concessions to telephones.Transmitter headphones are avail-able for the hearing impaired. Themost difficult accessibility issue ismoving vertically with elevators,so more handicapped parking wasallowed for on each garage level.

But the SuperDome is more thanjust a functional triumph. It is astunning addition to the Sydneyskyline, with its distinctivecrown appearance created by 18roof-support masts and their asso-ciated cables projecting into the airabove the roofline.

During construction, managersneeded to carefully analyze andmonitor the erection sequence ofthe roof, because the forces gener-ated by the method of construction

can significantly affect the final de-sign forces in the members.

The span of the main roof is 140m by 100 m, with an area of 12,500sq. m. There are 18 perimeter 600by 400 steel box columns at about20 m centers but this spacing in-creases to 32 m around the cornersof the roof. The columns extend 12m above the roof level, allowingthe roof to be supported by cables

that are tied back to the perimetercolumns.

In the center of the main roof is araised section measuring 40 by70 m, which consists of trussedspace frames about 5 m deep.These frames consist mainly of 250

and 310 universal column sections.Radiating from the raised space

frame in the center are 36 trusses at20 m centers that span 30 m to theperimeter of the building. Thesetrusses typically consist of 219 by6.4 CHS (G350) bottom chords and250 UC 73 and 250 UC 89 topchords. The top and bottom chordswere bent to the radius. Betweenthe radiating trusses is a parallelbeam (250 UB 25), which is sup-ported on ring trusses spanning be-

tween the radiating trusses,allowing for the purlin spacing tobe cut down to 10 m.

Around the perimeter of the roofis a horizontal truss that distributesthe thrust from the radial trussesinto the bases of the columns.These forces are generated by acombination of arching action ofthe roof and the horizontal compo-nents of the restraining cableforces. These forces are then resis-

ted by ring action in a reinforcedconcrete plant room slab.

The roof has strict acoustical re-quirements and was constructedwith a layering of elements. Thisconsisted of a top metal deck, twolevels of purlins, insulation and

plywood. In all, the weight of theroof system is 55 kg per sq. m.

The main roof weight, includingthe masts, columns, cables and the800 deep steel rakers, is 880 tons.This does not include the 25 km ofsteel purlins in the roof. More than26,000 sq. m of steel roof sheetingwas used.

The outer donut section of theroof was partially constructed inpie-shaped segments on theground, which included the roof

sheeting system. These were thenlifted into place on six temporarytowers. The infill sections besidethese elements were then com-pleted in the air. The raised centerroof was placed in erected position.When all the framing elementswere in position, including the ca-bles, jacking down the outer cablestensioned the structure. Finally, thetemporary towers were lowered,allowing the roof structure to take

all the dead loads.

February 2001 / Modern Steel Construction

Exterior of Sydney SuperDome.

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The structure has been designedto support substantial riggingloads of up to 70 tons, in additionto self weight, live and wind loads.A 30-ton gondola is suspendedfrom the center of the roof, sup-porting an array of large video

screens and scoreboards, giving theoperators great versatility for set-ting up various show configura-tions.

There is a wide veranda andcolonnade wrapped around thebuilding that, together with the ex-tensive use of steel, echoes Aus-tralian vernacular traditions. Theelliptical dome over the buildingfootprint is extended by the vary-ing veranda depth, with a maxi-mum of 30 m, giving added

interest to the faade.The roof of the foyer structure

consists of triangular trusses, span-ning up to 30 m, strutted off themain concrete structure. Two planetrusses were joined together toform the triangular trusses.

The columns supporting thefoyer trusses are linked with thecolonnade columns into a triangu-lar vertical truss. These verticaltrusses are extended into a tree

structure to support the edge of theveranda roof. The faade system iscompleted by horizontal trusses ateach floor level, which turn the ve-randa colonnade into a large spaceframe.

The result is a network of highlyinter-related lightweight members,each serving several functions, pro-ducing the appearance of a lacyveil of fine steelwork. The webwraps around the faade, creatinga spider-web effect from the inside.

Carl Yaeger, AIA, is a principal ofKansas City, MO-based Devine deFlonYaeger, and served as the firms princi-pal-in-charge on the Sydney Super-Dome.

Owner/developer:AbiGroup

Structural engineer:Taylor Thomson and Whiting

Architect:Devine deFlon Yaeger

Associate Architect:Cox Richardson

Construction:AbiGroup

Environmental Consultant:Manidis Roberts

Software:AutoCAD; Spacegass for struc-tural analysis.