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Standing on the Shoulders of Giants
S TA N D I N G O N T H E S H O U L D E R S O F G I A N T S : ANEVOLUTIONARYHISTORYOFARCHITECTURALSTRUCTURALSYSTEMS AFINALREPORT BY WILVSRUBARIII STRUCTURALENGINEERINGTRAVELINGFELLOWSHIP TABLEOFCONTENTS FOREWORD&INTRODUCTION 3 MASSCONSTRUCTION 6 TRABEATION 7 11 15 17 SHELLS&HYPERBOLOIDS 26 30 34 36 ARCHES VAULTS DOMES TENSILESTRUCTURES SPACEFRAMES BRIDGES AFTERWORD&PHOTOGALLERY 42 FOREWORD Itissaidthathistoryoftenrepeatsitself. Scholarlyadvocatesofthisphenomenon,inattempttoproveandprofessitsvalidity, oftencite,asevidence,profound,cyclicsynergiesinthehistoricalepochsofhuman civilization–intheriseandfallofgreatempires,intheconstantebbandflowof sociopoliticalconflict,andintherecurrencesofculturaltransformation,likeinthe AgriculturalandIndustrialRevolutionsofyesteryearwhichhavecometodefinethe historyofhumanlifeonEarth. Thephysicalnatureofearthlytimeitselfsingsdaily,theywouldargue,toacircadian rhythmcadence,whosepredictivepulseisfurtheraccentuatedbysuccessiverotations ofclimaticseasons,byprophesiesofweatherpatterns,andbyaccurateportendsof astronomicalevents.Furthermore,MotherEarthandFatherTime,alongwiththeir earthlyparentalcounterparts,canattesttotheresurgencesoffamiliarfads–music, dance,language,andfashion.Ineffect,tothehumanpsyche,historicaleventsindeed seemtorecurtimeandtimeagain Butwithinthisphenomenonliestremendousopportunity.Ashumans,wearetheonly earthlyspecieswithagency,freewill,andtheuniqueabilitytorecordandremember historicalevents;wearetheonlyspeciesthatcanrevisitourspecieshistory,celebrate ourvictories,and,moreimportantly,learnfromourmistakes. Notingthisopportunity,I,asbuilder,willarguethatarchitecture,too,repeatsitself. Buildingsaredesigned;theyarebuilt;theyfall.Designandconstructionprocesses havebeenrepeatedforthousandsofyears.Materials,forms,andsymbolshavebeen reiterated,refined,andreusedformillennia,evolvingintostructuresmoreelegant, moredurable,andmorerefinedthantheirhistoricpredecessors.Understandingthe importanceandimpactofthatevolutioninherentlylieswithinthehistoricalrootsof architectureandconstruction.Formillennia,lessonshavebeenlearned,inspiration hasbeendrawn,andprogressivestepshavebeenmadetoensureaconstantstateof evolutionofstructuralsystemswithinthebuiltenvironment. Theepichistoriesofarchitecturewerewrittenbythosewhoborewitnesstotheones whohadgonebefore,whoembracedthecompositesystemsofform,material, ornamentation,andsymbol,whostudied,reflected,challenged,andefficientlyrefined existingarchitecturalstructures,andwho,insodoing,stoodupontheveryshoulders ofthesearchitecturalgiantsandsawfurtherthananyoneelsehadeverseenbefore. We,myfriend,candothesame. TEMPLEOFKARNAK,LUXOR TEMPLEOFHERCULES,ROME THEPANTHEON,ROME PAGE 3 PANTEON,PARIS THEPARTHENON,ATHENS SANCARLO,ROME ST.PETER’SBASILICA,ROME REICHSTAG,BERLIN STANDINGONTHESHOULDERSOFGIANTS:FOREWORD INTRODUCTION Manhasalwayssoughtshelterfromtheelements.Fromthemostprimitivestick, stoneandanimalskinstructurestomodernsustainablebuildings,thefascinating evolutionofarchitecturalstructuralsystemscanbetracedthroughouthistory,noting theinfluenceofstyle,theinspirationofsymbol,and,especially,theprogressive developmentofmaterialefficiencyandtherefinementofstructuralform. Architecture,asahumanartandsocialactivity,isrelativelyinfantile–beginningwith therevolutionarydiscoveryofagriculturalcultivationandanimalhusbandrynearly 10,000yearsago.Thehistorictransitionfromnomadic,tribalculturestomore permanentsettlementsbroughtwithitthedawnofhumancivilization,and,forthe firsttimeinhistory,manbegantoshape,influence,andalterhisnaturalsurroundings byconstructinghisownbuiltenvironmentseparatefromthenaturalworld. Flimsytentlikestructureswerereplacedbymoresubstantialdwellings,constructedin resourcerichfertilerivervalleys.Numerousdwellingsgaverisetovillages;contact betweenfamiliesbecamemorefrequentandmorepersonal.Flourishingvillages developednetworksoftrade,betweenwhich,pathswereworn,crossingrivers, ravines,andgullies,requiringtheconstructionofroadsandfootbridgesmadeoflogs andnaturalfibervines. Thegrowthofcitiesrequirednewconstruction,bothphysicalandsocial.Common structureswerebuilttoservethesocial,political,and,especially,thereligiousneeds ofpeoplesinthecommunities,which,formostcultures,remainedcentraltothe organizationandstructureofthevillageitself.Indeedthroughouthistory,thelarger, moreimpressivearchitecturalmonumentswereoftenmotivatedbyspiritual requisites. Butbasichumanneedshavechangedlittleoverthecenturies.Likeourancestorswe eat,sleep,procreate,worship,andsocializeinourcommunitiesmuchinthesame waysashumanshaveforthousandsofyears.Tothatend,architectureisconsideredto beaconservativeart,changinglittleinitsfunctionalpurpose.Itis,however,withthe growthofpopulations,theadvancementofhumanintuitionandingenuity,andinthe increaseinpolitical,religious,andsocialinfluencesthatarchitecturehasseenmuch evolution.Increasingpopulationsrequiredefficientlydesignedhousing;larger,taller buildingswereerectedandbiggerspaceswereenclosedforreligiousandsocial activities.However,despitethesechangesinspace,peopleincitiesgather,still,tosee thesamesortsofspectacles,tosocializeinthesameway,andtoperformthesame basic,dailytasksasourancestorshaveforthousandsofyears. Toservethesebasicneeds,architectureismeanttoperformaspecificfunction– namelytoprotectpeoplefromweatherandtheelementsbyenclosingaseriesof PAGE 4 ROMANCOLISEUM,ROME STANDINGONTHESHOULDERSOFGIANTS:INTRODUCTION ROMANCOLISEUM,ROME SANTAMARIADELFIORE,FLORENCE EIFFELTOWER,PARIS 25DEABRILBRIDGE,LISBON PAGE 5 interconnectedroomsandspaces.Theconstructionandfunctionalservices ofbuildingsarereliantuponitsstructuralcomponents–columns,beams, floorslabs,walls–whichdelineateinternalandexternalspace.The materialpropertiesofthesestructuralcomponentsareutilizedtosafely transfertheloadscarriedbythestructuretotheground,maintainingthe integrityoftheentirestructuralsystemwhileimposingnaturalstrength limitstowhatisstructurallyfeasible. Withtheexceptionofmodernprestressedconcreteandhighstrength steel,modernstructuralmaterialsareverysimilartothoseusedbyour forefathers–wood,stone,bricks,andmasonrystilldominateconstruction inmanypartsoftheworld.Theymustbeusedinapplicationscompatible withtheirmaterialproperties.Thoughthematerialstructuralcomponents ofarchitecturehaveseenlittlealterationthroughouthistory,their arrangement,formandvaryingmaterialcompositionhaveindeedseen muchevolution. Itisinthisaspect–inthedevelopmentandrefinementofstructuralform– thatarchitectureisinaconstantstateofevolution.Thiscontinuousevolu tionispromptedandshapedbymanythings–changeswithinpolitical, socialandreligiousorganizations,aspreviouslyaforementioned–andalso bythesheerfascinationandnaturalcuriosityofthehumanmind. Forexample,manhasalwayshadanaspirationtoreachnewheightsinthe sky.This“TowerofBabel”complexhasledtotheerectionoftallerand tallerbuildings,sparkedtheaviationindustry,andlaunchedtheageof spaceexploration.Furthermore,manhasalsopushedthelimitsofthe horizontal,fromthemostbasicpostlinteltrabeationsystemsofprehistoric StonehengeandthetemplesofancientGreecetothemoreelegant, refined,curvaceousformsofmodernhyperboloid,tensileframe,and domestructures. Althoughmanhasseenmuchmoresuccessinhisquestforverticality,the tremendousaccomplishmentsofrevolutionaryhorizontalstructuralsys temshavespannedcenturiesandareworthexamination.Whatfollowsisa précisofthehistoricalevolutionoflongspanstructuralsystemsfrom prehistorytomoderntimes,highlightingtherevolutionaryarchitectureof theancientEgyptianandByzantinecivilizations,aswellastheremarkable engineeringfeatsoftheRomanEmpire.Suchasurveyismeanttobea thorough,yetnotexhaustive,accountofarchitecturalhistorythroughout WesternEurope,inordertounderstandnotonlytheinnovationsand achievementsofhorizontalstructures,buttoemphasizetheinherent influence,innovation,andinspirationofformandstructurethroughoutthe epicsagasofhistoricworldarchitecture. STANDINGONTHESHOULDERSOFGIANTS:INTRODUCTION MASSCONSTRUCTION Beforeproceedingtoaninvestigationoftheevolutionoflongspanstructuralsystems, itisimportanttounderstandwhatpromptedtheneedforsuchsystemsinthefirst place.Alongwiththerudimentarystickandskintentstructures,prehistoric architecturehaditsrootsinmassconstruction–thepilingofdirt,rocks,soil,andother loosedebrisintocivilinfrastructure,suchaswallsusedforprotectionagainstenemies, andembankments,levies,channelsforirrigationandfloodprotection,aswellasearly architecturalstructures,likemoundsforreligiousritesandroyalburials. Theearliestburialmoundswereknownasmastabas–rectangular,flatroofed structureswithslopingsides.Theearliestformofthemastaba,asseeninFigure1,was asquaremassbuiltofsoil,mudbricks,andstone.Mastabasmarkedtheburialsiteof prominentkingsandthesocialeliteofancientMesopotamiaand,later,ancientEgypt. Theburialchamberitself,thoughnothingmorethanashallowgrave,wastypically adornedwithgold,jewels,andotherriches;consequently,thetypicalonetiered mastabasgavelittleprotectionfromthievesandgraverobbers. Inordertoensureincreasedsecurityandsanctityoftheirrestingkings,theancient Egyptianswerethefirsttobuildmastabasontopofmastabas,thuscreatingtheiconic pyramidlikeformasseeninFigure2.Believedtobethefirstexampleofsuch constructionandthefirst“structurallyengineeredform,”theSteppedPyramidofKing Djoser(Figure3),designedandconstructedbyImhotep(whoisconsideredtobe history’sfirstarchitectengineer)around2630B.C.exemplifiedwhattheEgyptians calledthe“materialforeternity.”Thesquarebaseofthestructure,likemanylater pyramids,wascrisplyalignedwiththecardinalpointsandwasmeticulously constructedfromstoneblocksharvestedandtransportedviatheNileRiverfrom UpperEgyptianlimestonequarrieshundredsofmilesaway. Theparticularformofthestackedmastabainfluencedotherculturesascontact betweencivilizationsprogressed.TheburialmoundsofancientRomewere constructedinmuchthesameway.TheMausoleumofAugustus,seeninFigure4, wasbuiltaround28B.C.Constructedbymassingstoneandbrick,themausoleum wascircularinplanandconsistedofconcentriccircularmoundsofearthlinedwith cypresstrees. Theincreasingsizeofmassconstructedburialmounds,theemergenceofpyramids andgrandmausoleums,anevengreaterconcernabouttheftprevention,aswellasthe demandformorepermanentresidential,civic,andreligiousstructuresasmoreand moreculturesbecamecivilized,promptedtheneedtohavestructuresbuiltcontaining rooms,halls,passageways,andtunnels,theneedtocarryanddirectheavyloads throughstructuralelements,and,morespecifically,theneedforarchitecturally createdinternalspace. PAGE 6 FIGURE1.MASTABA FIGURE2.MASTABAPYRAMID FIGURE3.STEPPEDPYRAMIDOFDJOSER FIGURE4.MAUSOLEUMOFAUGUSTUS STANDINGONTHESHOULDERSOFGIANTS:MASSCONSTRUCTION TRABEATION Sincethedawnofcivilization,manhaslookedtotheskyinastronomicalwonderand incorporatedsuchponderingsintoreligiousandritualisticpractices.Inprehistoric communities,thesharedreligiousinterestswerecentraltothesocialstructureofthe villagesthemselves.Thisinducedaneedforpermanentstructureslastinggenerations, ensuringthepreservationofculture,tradition,andreligiousritesforfutureposterity. InsouthernEngland,onesuchstructurestillexists.Intheruralcountrysidenear SalisburylietheruinsofStonehenge.Thenameitself,givenduringmedievaltimes, means“placeofhangingstones”andadequatelyreferstothestructurethatgivesthe siteitsuniquecharacter:uprightstonecolumnswithmassivestonelintels. Constructedaround3000B.C.,Stonehenge,itisargued,wasaplaceofsolsticeritual, hypothesizedbasedonthesolarorientationofthecomplex.Thebasicstructure,as seeninFigure5,isamostrudimentaryexampleofpostlinteltrabeation.Builtof stone,themostpermanentconstructionmaterialoftheagehasprovendurable, lastingmillennia.Thelargestonesusedinconstructionwereactuallyquarriedand transportedformanyhundredsofmiles—anoblefeat—suggestingthatStonehenge wasaplaceofverysignificantimportance. ThebasicmonolithiccolumnbeamstructureofStonehengewasknownandutilizedby manyancientcivilizations.Forinstance,theancientEgyptiancivilizationsbuilt impressivestonetombsandtemplesbyusingthebasicpostlintelstructuralsystem. ButtotheEgyptians,structurewasmorethanphysical.Nosoonerdidtheirbasic structuretakeonaspecificformdiditbegintotakeonsymbol.Decorated ostentatiouslywithpaintings,carvings,andarchitecturaldetails,thecolumns,capitals, lintelsandmassconstructedwallsofEgyptiantemplesnotonlyservedafunctionof creatinginternalspace,butalsocommunicatedpower,wealth,right,anddivinity. AncientEgyptwasdividedintotwokingdoms:thenorthernLowerEgyptandthe southernUpperEgypt.Thesymbolsofthesetwokingdomswerethepapyrusandthe lotusflower,respectively,symbolizingthemainresourcecentraltotheirparticular economicindustries.Theimportantsymbolsbecameincorporatedintoarchitecture, ascanbeseeninthecolumnsandcapitolsofvariousEgyptiantemples(Figure6and Figure7).TemplesthatwerecommissionedandbuiltaftertheunificationoftheUpper andLowerKingdomsincorporatedbothofthesearchitecturalsymbolseitherbyusing bothstylesofcolumnsandcapitalssidebyside,likeinthe1300B.C.TempleofKarnak, asseeninFigure8a,orbyusingacompositeformofthepapyrusandlotusflower,like inthe237B.C.EdfuTemple,asseeninFigure8b. Similarly,theancientGreeksdevelopedthreedistinctivearchitecturalordersforstyles ofcolumnarcapitals.Forexample,thefamousGreekParthenonwasbuiltintheDoric order.TheveryspecificstandardsandproportionsoftheDoricorderwerethoughtto PAGE 7 FIGURE5.STONEHENGE FIGURE6.LUXORTEMPLE FIGURE8A.TEMPLEOFKARNAK FIGURE7.LUXORTEMPLE FIGURE8B.EDFUTEMPLE STANDINGONTHESHOULDERSOFGIANTS:TRABEATION reflecttheproportionsofamanandwereusedintemplesdedicatedtomalegods. Thecolumnsstooddirectlyonthefoundation,withoutabase.Thecolumnitselfwas flutedwithtwentyconcavegroovesandculminatedinaplain,smoothcapitalthat flaredfromthecolumntomeetasquareplatethatsupportedthebeam—whatthe Greekscalledtheentablature.Theentablatureconsistedofastonebeamcarvedwith triglyphsandmetopes,whichsculpturallyimitatedtheconnectiondetailofwood constructedtemples,whichpredatedthemorepermanentstonemonuments. IncontrasttotheDoricorder,whichcanbeseeninFigure9,theIonicorderstands uponabase.Itsslenderproportionsandcharacteristicpairofscrollingvolutesonthe capitalnegotiatethetransitionfromcolumntobeam.OneparticularGreektemple, theErechtheion,asseeninFigure10,wasbuiltintheIonicstyle.Thetemplealso containedacoveredterraceinwhichfemalesculptures,knownascaryatids,servedas thecolumnarsupportsfortheroofstructure(Figure11).ThefactthatthisIonic templealsohadacaryatid“PorchofMaidens”furtherreinforcedtheGreekbeliefthat theIonicorderreflectedtheproperproportionsofawoman.Ineffect,Greektemples dedicatedtofemalegoddesseswerebuiltintheIonicstyle. Thethirdarchitecturalorder,theCorinthian,wasbelievedtobethemostornateand refined.DrawinginfluencefromthelocalacanthusplantofCorinth,Greece,the Corinthiancapital,asusedintheTempleofDionysusinFigure12,hassimilar proportionstotheIonicorder,althoughslightlymoreslender.Typically,theGreeks usedtheCorinthianorderinsideofbuildings,whiletheRoman’s,whoadoptedthe Grecianarchitecturalorders,ascanbeseenintheclassical,IonicstyleTempleof Portunus,morereadilyembracedtheCorinthiancapitalanduseditextensivelyin buildingconstruction,asseeninthecircularTempleofHercules. Insomeapplications,theorderswerepaired,orsuperimposed,usingtwoor, sometimes,allthreeordersinthesamestructure,asseenintheRomanColiseum, Figure13andFigure14.Whensuperimposingtheseelements,theordersare progressedfromtheDoric,whichisbelievedtobetheheaviestandplainest,onthe bottom,totheCorinthian,whichisbelievedtobethelightest,slenderest,andmost intricate,onthetop.TheColiseumactuallyutilizesamorerefinedRomanversionof theCorinthianorder,inwhichtheymergethescrollingvolutesoftheIonicandthe ornatefoliageoftheCorinthianintowhatiscalledtheCompositeorder. Thefurtherrefinementofornamentationwithoutasignificantchangeinstructural formdemonstratesaninherentlimitationinmasonrycolumnbeamstructures. Therefore,therestofthediscussiononpostlinteltrabeationfocusesaroundcultural influence,exchangeofideas,andarchitectureasapoliticalsymbol. Forexample,theculturalexchangebetweentheancientGreek,Egyptian,andother civilizationsisnotonlyverballyapparentinlinguisticliteraryaccounts,butalsovisually apparentintheinfluenceofarchitecturalstyleandsymbol.Suchinfluenceisapparent inthearchitecturaldetailingofthecolumnsandcapitalsoftheSteppedPyramidof PAGE 8 FIGURE14.ROMANCOLISEUM— HIERARCHYOFARCHITECTURALORDERS FIGURE9.THEPARTHENON— DORICORDER FIGURE10.ERECTHEION— IONICORDER FIGURE13.ROMANCOLISEUM FIGURE11.ERECTHEION— PORCHOFMAIDENS FIGURE12.TEMPLEOFDIONYSUS— CORINTHIANORDER STANDINGONTHESHOULDERSOFGIANTS:TRABEATION DjoserComplexinwhichtheDoricinspiredcolumns,areplain,fluted,andwithouta base,althoughsomecolumnsinmorerecentadditionstothecomplex,dorestupona base,asseeninFigure15.Thiscolumnarstructure,whichpredatesthepapyrusand lotuscolumnsofLowerandUpperEgyptbymorethanathousandyears,hasengaged insteadoffreestandingcolumns,suggestingalessevolvedbuildingmethodologyand refinementofthebuildingstructure. TheTempleofQueenHatshepsut,seeninFigures16and17,furthercharacterizesthe interactionofcultureandtheinfluenceofarchitectureasasymbol.QueenHatshepsut assumedthethroneofEgyptuponthedeathofherhusband,ThutmoseII. Withholdingtherightfulreignfromherson,QueenHatshepsutwishedtorulewith powerandauthority;shewishedtobeviewedasstrongandironwilled,asadeity,as aking,andasaman–notawoman.Itshouldrightlyfollowthathertemple, completedaround1450B.C.,wasbuiltintheDoricstyle–bold,plain,unadorned–a directcorrelationtoGreektypology. Thespecificarchitecturalordersnotonlybecame‘types’andsymbols,butalso completesystems,andbuildingsbecamemodelsandtypesforotherstocopy.For example,theTempleofPortunus,showninFigure18,wasbelievedtobetheideal templeformofRomanarchitecture.Thisparticularexamplewascopiedthroughout WesternEurope,evidenceinthearchitectureoftheMaisonCarreeinNimesin southernFranceandtheL’egliseSainteMarieMadelieneinParis,showninFigure19. Eventoday,buildingsliketheUnitedStatesCapitol,theBritishHistoryMuseum,as seeninFigure20,andBerlin’sReichstagandBrandenburgGate,asseeninFigures21 and22,alsoattempttosymbolizeandcommunicatetheGrecoRomanphilosophiesof freedom,democracy,andequality. FIGURE20.BRITISHHISTORYMUSEUM FIGURE15.STEPPEDPYRAMIDOFDJOSERCOMPLEX FIGURE16.HATSHEPSUT’STEMPLE FIGURE17.HATSHEPSUT’STEMPLE FIGURE18.TEMPLEOFPORTUNUS FIGURE21.REICHSTAG FIGURE19.LAMADELIENE FIGURE22.BRANDENBURGGATE PAGE 9 STANDINGONTHESHOULDERSOFGIANTS:TRABEATION Theornamentalandstylisticrefinementsofthevariousstonetrabeatedstructuresdid nothingtoimprovethestructuralefficiencyofsuchsystems.Inherentlimitationsexist whenusingstoneasahorizontalspanningmember;stonebeamsarelimitedbythe tensionforcesthatdevelopalongtheirbottomsurface.Beyondtheirloadcarrying capacity,tensioncrackswouldformandwouldpropagatethroughoutthecross sectionofthebeam,resultinginfailure.Atypicalexampleofthisfailurewasnotedin Athens’TempleofDionysusandcanbeseeninFigure23. Thismateriallimitationrestrictedthespanlengthsbetweencolumns,and,ineffect,it governedthetotalvolumeofenclosedspaces.ThebeamsofancientEgyptiantemples spanned,atmaximum,fifteenfeet;typically,thespansweresignificantlysmaller.This ledtostuffy,crowdedenclosedspaces,asnotedinFigure24andFigure25;however, itpromptedthedevelopmentofnew,efficientstructuralformsthatwouldfullyexploit theextraordinarycompressioncapacityofstone,brick,andotherformsofmasonry.It wouldbethegreatmindsoftheRomanengineersthatwouldfindtheformto effectivelyputstoneincompressionandthedevelopmentofthearch. FIGURE23.TEMPLEOFDIONYSUS—STONEBEAMTENSIONCRACKING FIGURE25.TEMPLEOFDIONYSUS FIGURE24.LUXORTEMPLE—LIMITSOFSTONETRABEATION PAGE 10 STANDINGONTHESHOULDERSOFGIANTS:TRABEATION ARCHES BeforetheRomans,therewereearlyattemptsatincreasingthestructuralefficiencyofstone trabeatedsystems.Inthediscussionofancientmastabas,theSteppedPyramidofZoser,and theMausoleumofAugustus,itwasnotedthatthesemassconstructionstructureswere erectedasrestingplacesforthedeadandwereinneedoftunnels,chambers,andlarge, internalspaces.DrawinginspirationonceagainfromearlyMesopotamianbuildingpractices, theancientEgyptiansexperimentedwithbasicformsofcorbelvaulting.Corbelling,asseenin Figure26,isthecreationofinternalspacebytheprogressivecantileveringofstones, structurallyredirectingandtransferringtheverticalloadpathintothewallsofthecorridor. Thissystem,whichworkedwellonsmallscales,asinthenarrowtunnelsandchambersofthe GreatPyramids(Figure27),hadsimilar,inherentlimitationsasthepostlintelsystemsanddid noteffectivelyexploitthecompressioncapacityofthestonesthemselves. SimilarcorbellingeffortsareapparentinIslamicarchitecture.Characteristicandfundamental toIslamicstructuresisthemuqarnaarch,whichisconstructedbylayeringaseriesofsmall, pointedniches,whichprojectbeyondthosebelowit.Thecommontermforthisformisthe “stalactitearch,”whichisappliedtotheundersideofcorbellikearches,underneathvaults, andinthesquinchandpendentiveareasofdomes,theareawhichnegotiatesasquareplanto theroundbaseofthedome.Examplesofmuqarnavaultscanbefoundintherich,Islamic architectureofsouthernSpain,especiallyintheAlhambrainGranada,asseeninFigure28. However,itwastheRomansthatrealizedtheextraordinarycompressivecapabilitiesofstone, whichledthemtodeveloptheclassicRomanroundarch,asseeninFigure29.TheRoman roundarch,constructedbybricklayingstonesontopofasemicircularwoodenformwork, effectivelyputallofthestonesinpurecompression.Afreebodydiagramofthekeystone showsagravityorloadinduced,verticalforceappliedtothestone.Theforceisresisted partlybyshearfrictionforcesalongtheblockinterface,andtheresultantissafelytransferred tothefoundationorpierthroughwhatiscalledthelineofthrust.Agoodexampleofthe RomanroundarchisfoundintheRomanColiseum,seeninFigure30. TheRomansusedthenewlyengineeredarchformextensivelyintheirconstructionofcivil infrastructure,particularlyintheirconstructionofbridges,aqueductsandviaducts.Asuperb exampleoftheRomanaqueductisthePontduGard,builtinthemiddleofthefirstcentury A.D.Theaqueduct,seeninFigure31,wasbuiltinthreelevels,completelyoutofstonewith outtheuseofmortar.Thestoneswerepreciselycuttofitperfectlytogether,muchlikethe ancientEgyptiantemples,withouttheuseofabondingagent. Attheheightoftheirempire,theRomanshadbuiltmorethan50,000milesofroadsand bridges.Thispromotedculturalexchange,ideas,and,ineffect,architecturalformsandcon structiontechniques.ArchconstructionflourishedinotherareasofWesternEuropeandled tothedevelopmentoficonicstructuresoutsideofRome.Forexample,theCharlesBridgein PAGE 11 FIGURE26.COREBELARCH FIGURE29.ROUNDROMANARCH FIGURE27.GREATPYRAMIDSOFGIZA FIGURE28.LAALHAMBRA—MUQARNA FIGURE30.COLISEUM —ROUNDARCH FIGURE31.PONTDUGARD STANDINGONTHESHOULDERSOFGIANTS:ARCHES Prague(Figure32)isoneoftheworld’smostfamous bridges,characterizedbyitssimple,roundedarchform. TotheRomans,thearchwasnotjustastructure–itwas alsoasymbol.Itwasasymbolofherempire,her conquest,herglory.AttheheightofRomanrule, triumphantarches(examplesofwhichcanbeseenin Figure33,Figure34andFigure35)wouldbeerectedto commemorateanotablebattle,avictory,andyet anotherconquestofdistantlands.Thetriumphalarches wouldbeinauguratedinvictoryparadesthroughthecity –markingthebeginningandendingoftheseancient processions.Thearchembodiednoblehonorand,like theformitself,begantotranscendculturalboundaries. NotableleaderslikeNapoleonBonaparte,Constantine andevenafewBritishmonarchswouldeventuallyerect triumphalarchesintheirownname. TheRomanroundarchwasindeedmorestructurally efficientcomparedtotheantiquatedstonepostlintel trabeatedsystems;however,therewerestilllimitstoits span.Sincemoderndayphysicsandstructuralmechanics didnotyetexist,stonemasonsandmasterbuildersin thetimeleadinguptothemedievalGothicage,through trialanderrorattemptsatlengtheningthespandistance ofarches,foundthatroundarcheshadinherent weaknesspoints,atapproximatelythirtydegreesfrom thehorizontal.Itisnowknownthatthelineofthrustof masonryarchesisnotsemicircular,butrather,parabolic, asseeninFigure36.Inlongerspans,thislineofthrust wouldnotbecarriedthroughtheroundstructuralform. This,ineffect,ledtothedevelopmentofpointedarches, showninFigure37,whichmorecloselyfitthelineof thrustloadpathandmoreefficientlydirectedthetothe foundation.Anapplicationofthisstructuralformcanbe notedinFigure38,thePisaCathedral. Tocontroltheseinherentweaknesseswithinthearch, masterbuildersbegantodevisewaystoreinforcethe structure.Thisresultedinthedevelopmentofdifferent formsofarchandvaultbuttressingsystemswhich effectivelyrestrainedthetendencyforarchesto,ina sense,buckleoutward,undercompressionloads. FIGURE32.CHARLESBRIDGE FIGURE33.ARCHOFSEPTIMIUSSEVERES FIGURE35.ARCDETRIOMPHE 30° FIGURE36.LINEOFTHRUSTINROUNDARCH FIGURE37.LINEOFTHRUSTINPOINTEDARCH PAGE 12 FIGURE34.ARCHOFTITUS FIGURE38.PISACATHEDRAL STANDINGONTHESHOULDERSOFGIANTS:ARCHES AllthreesystemsaredetailedinFigure39.Thefirstsystemrequireda minorretrofitting—ametaltiewasconnectedtothearchsupports. Thiswasacommonformofarchbuttressing,attractiveonlyforits economyandeffectiveness;however,theinterruptionoftheelegant archformdetractedfromitspopularity.Anexampleofthistypeof buttressispicturedinFigure40,theBlueMosqueinIstanbul,Turkey. Thesecondofthesebuttressingsystemstobedevelopedwasmass buttressing,whichinvolvedabuildupofmaterial,similartomass constructionofretainingwalls.Thisledtoamorerefinedformofwall buttressing,asseeninParis’St.ChappelleinFigure41,whichgave addedstabilitytothearchvaulting. AthirdformofbuttressingthatdevelopedcametodefineGothic architecture—theiconicflyingbuttress,asseenintheNotreDame CathedralinFigure42.Flyingbuttressesdirecttheloadofarched vaultingsystemsawayfromtheexternalwallsofthebuilding.This reinforcesthearchedsystemwhilesafelytransferringtheloadtothe ground,whileallowingformorewindowsandglasstobeincorporated intothewallstructure,and,therefore,allowingnaturallightandairto filterintotheenclosedspace. Itisnotuncommontofindmodernexamplesofarchedstructures, especiallysincetheemergenceofalternativemetalmaterials,likeiron andsteel.Theengineeringpropertiesofthesematerialsmadepossible unprecedentedstructuralforms,liketheEiffeltowerasseeninFigure 43,thethreehingedarchstructureofthePiraeusRailwayStation,as seeninFigure44,andthearchedrooftrussesoftheAEGTurbine Factory,asseeninFigure45. FIGURE43.EIFFELTOWER PAGE 13 FIGURE39.TIE,WALL,ANDFLYINGBUTTRESSES FIGURE41.ST.CHAPPELLE—WALLBUTTRESS FIGURE40.BLUEMOSQUE—TIEBUTTRESS FIGURE44.PIRAEUSRAILWAYSTATION FIGURE42.NOTREDAME—FLYINGBUTTRESS FIGURE45.AEGTURBINEFACTORY STANDINGONTHESHOULDERSOFGIANTS:ARCHES Continuingwiththerefinementofformintermsofmasonrystructures,theGothic archprovedmuchmoreefficientindirectingloadpathsthanthepureRomanround arch.However,itwasnotuntilthelate19thcentury,aftertheonslaughtofmodern mathematics,physics,andmechanicsdidengineersandscientistsbeginto experimentwithrefiningthestructuralarchedform.Thankstostructural experimentsbyarchitectengineerAntonioGaudi,thelineofthrustinducedbythe loadsonaparticularstructurecanbefoundbysimplyusingapieceofstring. Inhisexperiment,Gaudiestimatedtheverticalloadsthatwouldactonhisstructure– loadsthathewantedtoresistwithanarchedform.Hescaleddowntheappliedloads andattachedweightstoastringattheappropriateloadpoints.Theweightswould makethestringsagunderthegravityloadcondition.ShowninFigure46,thepure tensionshapeofthestring,whenflippedvertically,Gaudiconcluded,isthemost efficientarchedstructuralform–acatenaryarchloadedinpurecompression(shown inFigure47)–foranygivenloadcase. ThecatenaryarchformisusedextensivelyinGaudi’sworks,includinghisfamous SagradaFamiliainBarcelona,Spain(Figure48)andintheworkofSantiagoCalatrava, includinghisOlympicComplexinAthens,GreeceandhisCiutatdelesArtsiCienciesin Valencia,Spain(Figure49andFigure50,respectively). PURETENSION PURECOMPRESSION FIGURE46.TENSIONSTRINGEXPERIMENT FIGURE47.CATENARYCOMPRESSIONARCH FIGURE50.WALKWAY—CIUTATDELESARTSICIENCIES FIGURE48.SAGRADAFAMILIA PAGE 14 FIGURE49.WALKWAY—2004OLYMPICCOMPLEX STANDINGONTHESHOULDERSOFGIANTS:ARCHES VAULTS Thediscussionofarches,inessence,islimitedtoatwodimensionalconversation– basicallyahorizontalspanresistingverticalloads.Inearlyapplications,archeswere onlyusedinthissense,asnotedinthecivilinfrastructureexampleofthePontduGard andinthesculpturalexamplesoftriumphalarches.Archapplicationswerealso integratedintobuildingsystems,asseeninFigure51,thechurchofSt.Minatoal MonteinFlorence.Thisparticularchurchhasmasonryarchribseverysooftenalong thenaveofthechurch,alongwithatwodimensional,pitched,woodentrussroof.This truss,incombinationwiththereinforcementstrengthofthemasonryarch,comprises theentirecompositeroofstructuralsystemofthechurch. However,thelimitsofwoodenspans,theirsusceptibilitytofire,andthenoted materialefficiencyanddurabilityofmasonrypromptedtheexperimentationof threedimensionalvaultingsystemsmadeentirelyofstone. Thesimplestformofmasonryvaultisknownasabarrelortunnelvault.Abarrelvault isastructuralelementformedbytheextrusionofasinglecurve,inthecaseof catenaryorRomanroundarches,orpairofcurves,inthecaseofGothicpointed arches.AnexampleofanextrudedbarrelvaultcanbeseeninFigure52.Effectively, thiscreatesasseriesofarchesplacedsidebyside,onerightaftertheother.The earliestknowntypesofmasonryvaultingwereusedextensivelythroughout Mesopotamia,aswellasinancientRomanapplicationsofwarehousesandchurches, ascanbenotedintheruinsoftheBasilicaofMaxentiusinFigure53.Otherexamples includetheaforementionedtriumphantarches,showninFigure54,aswellasthe massivebarrelvaultsofSaintPeter’sBasilica,showninFigure55. Aswithsimplearches,barrelvaultstructuresgenerateanoutwardthrustthatmustbe controlled.Thereareseveralwaysofcontrollingthishorizontalthrust.Thefirstisby makingthewallsextremelythickandstrong,whichisuneconomicalandmost inefficient.Secondly,barrelvaultsmaybebuiltparalleltoeachother.Thethrustfrom onevaultthuslynegatesthethrustoftheother.Thisallowedforanincreaseinthe uninterruptedinteriorspace,andonlythethrustsoftheoutermostvaultswouldneed tobecontrolled.Thirdly,thevaultsmaybebuttressedbymass,wallbuttressesor, moreelegantly,byflyingbuttresses. However,themostsophisticatedwayofcontrollingthehorizontalthrustswasto intersecttwobarrelvaults,asdemonstratedinFigure56,thusreducingmaterial, openingspacesforwindowsandlight,andproperlydirectingthehorizontalthrustsof thevaults,throughtheintersections,tofourmanageableverticalpointloads,which eliminatedtheneedforcontinuouswallsupports.Thisledtofurtherexperimentation andimprovementofthenewlyengineeredgroinvaultedstructuralsystem. FIGURE52.BARRELVAULT FIGURE51.ST.MINIATOALMONTE FIGURE56.QUADRIPARTITEGROINVAULT FIGURE53.BASILICAOFMAXENTIUS FIGURE55.ST.PETER’SBASILICA PAGE 15 FIGURE54.TRIUMPHALARCH STANDINGONTHESHOULDERSOFGIANTS:VAULTS AlthoughtheRomansutilizedthisparticularstructuralsystemintheconstructionof theColiseum(asseeninfigure57),thefirsttrialanderrorexperimentswithlarge scalegroinvaultsystemsarehistoricallyassociatedwiththeambulatoryofSaintDenis BasilicainParis,France,aroundtheyear1140.AsseeninFigure58andFigure59,the vaultsofSaintDenis,althoughquiteheavy,squat,andunrefined,influencedan architecturalmovementthatwoulddefinetheGothicageandpushthelimitsof masonrystructures. Thecathedralsthroughoutthemedievalperiodareprimecharacteristicexamplesof theevolutionandprogressiverefinementofmasonryvaults.ShowninFigure60,the vaultofChartresCathedral,completedaround1220,isaquadripartitemasonryvault, meaningtheintersectionoftwobarrelvaults,whichresultsinfourpartitions.Thevault itselfrequiredmassivemasonrypiers,whichleftlittleroomforstainedglasswindows andnaturallight.Theinternalspaceiscold,dark,andtheroofisseeminglyheavy. Throughtimecamerefinementinformandmaterialefficiency.Ascanbeseeninthe sexpartitevaultingofNotreDameCathedral(Figure61),whichwascompletedaround 1245,andinthequintessentiallyvaultedchapelofSt.Chappelle,showninFigure62 andFigure63,thin,gracefulpiersreplacedbulkyones,allowingforlessmaterial,more windows,morelight,andamoreefficientstoneskeletonduetotheevolvedtrialand errorconstructiontechniquesofmedievalmasterbuilders. DuringthelateGothicperiod,vaultingsystemsbecameevenmoreintricate.Some examplesofsuchvaultscanbeseeninFigure64.St.VitusCathedralinPrague, completedaround1344,isanexampleofHighGothicribnetvaulting,notthat dissimilarfromthependantstylefanvaultingofHenryVIII’schapelinWestminster AbbeyshowninFigure65. TheSpanishCatalanarchitectAntonioGaudimadeextensiveuseofcatenaryarches andvaultsinhisarchitecturalworks.Capitalizingonthestructuralefficiencyofsuch arches,Gaudiincorporatedsimilarvaultsintothethinshellstructuralsystemsofhis famousSagradaFamiliaandtheCasaMila,showninFigure66,Figure67andFigure68. FIGURE57.ROMANCOLISEUM FIGURE58.ST.DENISBASILICA FIGURE60.CHARTRESCATHEDRAL FIGURE64.ST.VITUSCATHEDRAL FIGURE66.CASAMILA FIGURE61.NOTREDAMECATHEDRAL FIGURE65.HENRYVIII’SCHAPEL FIGURE67.SAGRADAFAMILIA FIGURE63.ST.CHAPPELLE FIGURE68.SAGRADAFAMILIA FIGURE59.ST.DENISBASILICA FIGURE62.ST.CHAPPELLE PAGE 16 STANDINGONTHESHOULDERSOFGIANTS:VAULTS DOMES Consideredearthlyconstructionsofheavenlyspheres,domesmeetthechallengeof creatinglarge,enclosedspaceswithouttheuseofinternalsupports.Constructedby revolvinganarchedform,eitherround,pointed,orcatenary,aboutacentralaxis, (depictedinFigure69)domesadequatelyholdtheirownwhenitcomestocontrolling outwardthrustscreatedbyarchedandvaultedsystems.However,uniquetodomes, tensionhoopstressesaregenerated–forcesthatmakesthedomebulgeunderits ownweightincombinationwithexternalloading–whichmustbecontrolled. TheengineersoftheancientRomanknewallabouthoopstress,howtocontrolit,and howtominimizetheloadsthatdomeshadtocarryinordertomaximizethespans theycouldachieve.ThelegendaryPantheon(Figure70andFigure71),whichwasbuilt inthefirstcenturyA.D.,achievedunprecedentedspans,duetothediscoveryand extensiveuseofearlyconcreteproductsasconstructionmaterialsandbyingeniously alteringtheformofthestructureitself.Theenveloping142footspanofthePantheon, whichheldtherecordforlongestspanfor1500yearsuntilitwassurpassedbythe domesoftheRenaissance,wasaccomplishedbyagradualchangeinthethicknessof thedomefrombasetooculus,decorativecoffering,whicheffectivelyeliminatedma terialand,ineffect,weight,andtheincorporationoflightermaterialsintheconcrete mixture,whichalsoreducedtheselfweightofthedome. Abuildupofmaterialwasplacedatthebaseofthedomeasaformofmasswall buttressingagainstthegeneratedhoopstresses,andtheinfamousoculusnotonly eliminatedmaterialweight,butalsoservedasaforcecontrollingtensionringforthe crownofthedome. TheancientRomanswhoconstructedthePantheonhadeffectivelydiscovered concrete,whichcouldbeeasilymoldedandformedintoanydesiredshape,provided therewasadequateformwork.However,afterthefalloftheRomanEmpire,the knowledgeofconcreteconstructionwaslostinthepagesofhistory.Medievalbuilders knewnothingoftherevolutionarymaterial;sothedomesconstructedintheearlyand lateGothicagesleadinguptotheRenaissancewererelativelyprimitivecomparedto theRomanmarvelofthePantheon. Inearlymedievaldomeconstruction,builderswoulderectaseriesofrevolving, transverseribarchesandinfillthespaceswithbrickorstonework.Theresultwasa vaulteddome,liketheoctagonaldomeoftheCathedralofValencia,picturedinFigure 72,builtcircaA.D.1500.Theeightribspokeswerearrangedinacircularpattern,and, sincetheywerefreestandingarches,thespandistance,whichisrelativelyminiscule comparedtothePantheon,requiredheavybuttressingalongthedome’sperimeter. SimilardomeconstructionwasusedmanyyearslaterinthebuildingofSantaMaria dellaSalute,achurchbuiltin1631inVenice,Italy,showninFigure73. PAGE 17 FIGURE69.REVOLVEDARCHDOME&HOOPSTRRESS FIGURE71.PANTHEON FIGURE70.PANTHEON FIGURE72.SAGRADAFAMILIA FIGURE73.SAGRADAFAMILIA STANDINGONTHESHOULDERSOFGIANTS:DOMES Thistypeofdomeconstructionwasnotrevolutionaryduringthemiddleages.The legendarydomeoftheHagiaSophia,completedaroundA.D.500,picturedinFigure74 andFigure75,wasdesignedasaseriesoffortyribs,whichallowedforaseriesofforty windowstobeplacesbetweenthem.Thisgivestheillusionthatthedomeis“floating” overtheinteriorspace–aconceptenvisionedbythedesignertofloodthespacewith lightandtoevokeemotionsofwondermentandcelestialproximitytotheheavens. The102footspanrivalsthatofthePantheon;however,duringitslonghistory,the domehasbeenbuiltandrebuiltatotalofthreetimes,duetodestructionbyfireand structuraldesignfailuresattributedtoinefficientbuttressingofthemainandside hemisphericdomes. TheuniqueinterioroftheHagiaSophiacanbeattributedtoitsuniquegeographic location.LocatedinIstanbul,Turkey,whichwasoncetheEasternRomancapitolof Constantinople,spanstwocontinents,thusitsarchitecturalstyles,painting,and ornamentationareheavilyinfluencedbydifferentcultures.TheHagiaSophiawasfirst builtasaRomanCatholicchurch,decoratedwithintricatelypristinemosaicsinthe Byzantinestyleofartandarchitecture;inlatercenturies,withthespreadofIslam,the churchwasconvertedtoamosque,anditsmosaicswerecoveredbylayersofstucco, whichwerethenpaintedwithIslamicsymbolsandgeometricdesignscharacteristic. Thespreadofdifferentstylesofartandarchitecturecanbeseenviaexamples throughoutWesternEurope.VeniceechoedtheidealpositionofConstantinopleatthe meetingpointofancienteastwesttraderoutes.SaintMark’sBasilicainVenice,Italy, seeninFigure76,isbuiltanddecoratedinmuchthesamestyleastheHagiaSophia,as notedbyextensiveByzantinemosaicsandpaintingsthroughoutthecathedral. However,thedomesofSaintMark’s,showninFigure77andFigure78,completed500 yearsafterthefloatingdomeoftheHagiaSophia,werebuiltinanewformandstyle achievedbyemployingnewmaterialsandimplementingnewconstructiontechniques. TheonionshapeddomesofSaintMark’sBasilicawereformedbyconstructingtwo shells–aninterior,structuralshellandanexterior,aestheticshell.Theinteriorshells ofthedomeswereconstructedinasimilarfashiontotheHagiaSophiaandthe CathedralofValencia.Itconsistedofaseriesofspokelikemasonryribs,whichallowed forwindows,andfinishedwithastoneandbrickinfill.Theouterdomes,whichwas added200yearslater,isformedoutofwoodandcoveredinleadpanels.Theabilityto bendwoodintoadesiredshapeallowedthedomestotakeoncurvaceous,onionlike forms,whichwereintendedtoblendinwiththenewlyappliedGothicfaçadeand ornamentationoftheBasilica’sexterior. TheGothicagesawlittleimprovementsinthedesignandconstructionofdomes. However,theflourishofideas,creativegenius,andthenewemergenceandimpacts ofmathematicsandscienceduringtheItalianRenaissancepromptedunprecedented accomplishmentsintermsofspanninginteriorspace. PAGE 18 FIGURE74.HAGIASOPHIA FIGURE75.HAGIASOPHIA FIGURE76.FAÇADEOFST.MARK’SBASILICA FIGURE77.INTERIOROFST.MARK’SBASILICA FIGURE78.DOMESOFST.MARK’SCATHEDRAL STANDINGONTHESHOULDERSOFGIANTS:DOMES FlorencewasacitythatneverforgottheclassicalpastofItaly.Buildingssuchas SaintMinatoalMonte,showninaprevioussection,werebuiltintheclassical style,influencingartistsandarchitectsduringtheyearsleadinguptheartistic flurryoftheRenaissanceperiod.Eventheoctagonalbaptisteryandthe similarlyshaped,crossingofthecathedralofFlorence,laterchristenedSanta MariadelFiore,weredesignedintheclassicalstyle,derivinginfluencefrom ancientRomantemples.However,theambitiouslyextensiveoctagonalcrossing ofthecathedral,alongwiththeconstructionofatowering180foothighthin walledoctagonaldrum,causedadilemmaintheoveralldesign–thecrossing couldnotbespannedbysimplyraisingadomeonatraditionalwoodenframe work,knownascentering,duetoitsheightandthewidthofthespan. Intheend,thenovelsolutioncamefromFilippoBrunelleschiwhowasa classicallytrainedsculptor,artist,andarchitect.Brunelleschiwonadesign competitionwithhismodelofadomethat,byitscompletionin1456,boldly definedtheRenaissance(seeFigure79).Mergingartandscienceintoastandard forthefuture,Brunelleschiinsistedthathisdomecouldbebuiltwithoutthe assistanceofwoodenformwork.Thedomeconsistedofaconcentricseriesof selfsupportinghorizontalringsofbrickandstone,reinforcedbyaninfillof brickworklaidinareinforcingherringbonepattern,depictedinFigure80,which addedstiffnessandstabilitytotheshellstructure.Furthermore,thedomewas constructedintwolayers–aheavy,thickinteriorshell,andathinner,weather protecting,exterior,whichallowedfortheconstructionofastaircasebetween them,allowingeasyinspection,repair,while,morerecently,sufficingthecurios ityoftouristsandvisitors. Taperingastheyriseabovethecrossing,theinnerandouterdomesarelinked andreinforcedby24verticalribsofsandstone,eightlargeribsdefinethe octagonaldrum’scorners,whilesixteensmallerribsareembeddedand distributedbetweenthem.Atwentyfootdiameteroculuscrownsthedomeand supportsthelanternwhichwasinstalled,posthumously,inhonorof Brunelleschi.Anothermajorinnovationofthedomeconstructionwasthegirdle ofchains,someofwood,someofstone,andironcrampsthatrestrictedthe domeshoopstresses.Brunelleschi’sdomebecame,almostovernight,the standardbenchmarkbywhichallotherdomeswouldbemeasured. FIGURE80.HERRINGBONEBRICKPATTERN PAGE 19 FIGURE79.SANTAMARIADELFIORE STANDINGONTHESHOULDERSOFGIANTS:DOMES DuringtheRenaissance,otherartistsandarchitects,likeDonatoBramante,begantoadopt, change,andcodifytheclassicalrulesofGreekandRomanarchitecture.HisTempietto, completedin1502,showninFigure81,isacommemorativemartyriuminthecourtyardof SanPietroinMontorio,asmallchurchbuiltuponthesupposedsiteofthecrucifixionofSaint PeterinRome.ThetempleisconsideredtobeamasterpieceofHighRenaissance architecture,perfectlyproportionedandharmoniouslydesignedwithDoriccolumns,aDoric entablaturedepictingbothChristianandpagansymbols,andadome.Althoughviewedasa pieceofsculptureratherthanarchitecture,theTempiettoembodiedalloftheelementsof classicalarchitecture,and,alongwithBrunelleschi’smasterpiece,servedasmodeland inspirationforotherRenaissancearchitects,includingthelegendaryMichelangelodi LodovicoBuonarrotiSimoni. FIGURE82.MICHELANGELO’SDOME FIGURE79.FAÇADEOFST.PETER’SBASILICA FIGURE84.INTERIORDOMEOFST.PETER’SBASILICA FIGURE81.BRAMANTE’STEMPIETTO PAGE 20 FIGURE85.PIERSSUPPORTINGDOME Michelangelo,whoinheritedthetitleofchiefarchitectofthenewSaintPeter’sBasilicain1546 aftermanyillustriouspredecessorsincludingBramanteandRaphaelSanzio,waschargedwith thedauntingtaskofdesigningthedomeofthelargestchurchinChristendom.With BrunelleschiandBramanteinmind,Michelangelodesignedhisowntoweringmasterpiece. DirectlyoverwhatmanybelievetobethetomboftheearlyChristianmartyr,thedouble vaultedbrickdome,showninFigure82,Figure83andFigure84,rises452feetintotheairand spansadiameterof137feet,closelyrivalingthatofBrunelleschi’sFlorentinetourdeforce. Rowsofwindowspiercethe16ribbedcompartmentsbetweenthearchesastheycurvetoward thelantern.ThoughnolongervisiblefromeverywhereinRome,asMichelangelointended,the leadcovereddomestilldwarfstheotherRenaissancechurchesinitstoweringheight. Theimmensedomesitsatopfourmassivepiers(showninFigure85)morethansixtyfeetwide thatanchorthefourarcheswhichsupportsthedome’sbase.Thetransitiontoaroundbaseis STANDINGONTHESHOULDERSOFGIANTS:DOMES negotiatedbyfourpendentivesbetweenthearchesandthecirculardrum.Thedome wasconstructedsimilarlytoSantaMariadelFiore,byusingdoubleshellsofmasonry andwrappedwithtwoironchainstoeffectivelycontrolthehooptensionstressesthat weregeneratedinthemassivestructure.Nearly150yearslater,cracksbeganto propagatethroughoutthedome.In1742,apioneerinstructuralmechanicsnamed GiovanniPolenideterminedthattheproblemcouldbesolvedbytheadditionoffive moreironchainstocontroltheoutwardthrustofthedome. AfterLondon’sdevastatingGreatFirein1666,SaintPaul’sCathedral,showninFigure 86andFigure87,wasrebuiltasperthedesignofarchitectSirChristopherWren, whichincludedadomeconstructedwithnovel,innovativetechniquesthatmadeprior methodsobsolete.WhileadmiringthedoubleshellmasonrydomeofSaintPeter’s BasilicainRome,Wrenwasalarmedbythestructure’scracking.Furthermore,the rubblefilledpierswhichwouldsupportWren’sdomebegantospallevenbeforethe dome’sdesignwascomplete.Thisdemandedthatthemassivedomebenotonlystruc turallysound,butalsoextremelightinweight. Wrenaddressedbothdemandsbyusingthreeseparateshellsinhisdome:a lightweight,inner,eighteeninchhemisphericaldomemadeofmasonry,acentral, eighteeninchcatenary,coneshapeddomealsomadeofbrick,andanoutershellof leadsheathedtimber.Onlythecentralcatenaryshellstructurallysupportsthe850ton lanternthatcrownsthedome.Eightpiersandfourtowerlikebastionsarejoinedbya seriesofarchesandbarrelvaultsthathelpanchorandstabilizethedome.Inaddition, asingleironchainisusedtoresisttheoutwardhooptensionforcesfromspreading throughoutthesystem. TheinternalcatenarydomeofSaintPaul’sCathedral,thoughinnovativelyintegrated intothedesignofthestructure,wasnotaparticularlynovelstructuralform.Infact, catenarydomeswerebeingconstructedpriortotheMiddleAges,beforeGothic cathedralsand,especially,beforethemorerecentworkofAntonioGaudi,whois consideredtobethemainexploiterofthisparticularform.Asanexample,the BaptisteryatthePisaCathedralhas,asitsmainstructuralform,acatenarymasonry domeascanbeseenonthefollowingpageinFigure88.Thisstructurewascompleted in1363,centuriesbeforethemastermasonsoftheMiddleAgesortheinnovative geniusesoftheRenaissanceutilizedthisefficientstructuralformintheirdesigns. AftertheRenaissanceperiodofclassicalarchitecture,architectsandbuildersbeganto playwithotherdifferentformsandshapesofvaultedspaces.Thisledtotheuseof ovals,intricatecoffering,andcomplexshapesindomeconstructiontypicaloftheBa roqueperiodofartandarchitecture.Forexample,thechurchofSant’AndreaalQuiri nale,designedbythefamousartistGianLorenzoBerniniinthe1660sisconsidered oneofthefinestexamplesofRomanBaroquearchitecture,combiningartandstruc tureinoftenseamlesscombinations.Thedomeofthechurchisanovalshapedmono FIGURE86.DOMEOFST.PAUL’SCATHEDRAL FIGURE87.FAÇADEOFST.PAUL’SCATHEDRAL PAGE 21 STANDINGONTHESHOULDERSOFGIANTS:DOMES shelldome,showninFigure89,supportedby10masonryribsandacofferedmasonry infill.Thesmalloculussupportsalanternthat,incombinationwithotherstrategic sculpturesofmarble,glassandgilding,floodthespacewithcelestialbeamsoflight. SimilarinstyleandformtoSant’AndreaistheRomanchurchofSanCarloalleQuattro Fontane–theinteriorofwhichwasredesignedbyarchitectFrancescoBorrominiin 1637.Thechurch,depictedinFigure90,withitsundulatingfaçadeandintentional departurefromclassicism’scrisplineation,isalsoconsideredaniconicmasterpieceof Baroquearchitecture.Borrominifavoredacorrugatedovaldomeintricatelycoffered withasystemofcrosses,ovals,hexagonsandoctagonswhoseproportionsdiminish towardsthecrowninglantern.Thesolesourceoflightforthespace,thelanterndepicts partingcloudsflankingthesidesofapure,whitedove–asymbolofpurity,redemption, cleansing,andspiritualrenewal. OvaldomeswerenotexclusivelyBaroque.PriortotheItalianRenaissance,muchlikeits sisterbaptistery,thePisaCathedral,consecratedin1118,wasadornedwithblackand whitemarble,greystone,agildedceilingandafrescoedovaldome.Thedome, depictedinFigure91,issetuponhighandnarrowpointedarches.Itisconsideredtobe ofIslamicinspiration. FIGURE89.SANT’ANDREAALQUIRINALE FIGURE91.PISACATHEDRAL PAGE 22 FIGURE88.BAPTISTERYATPISACATHEDRAL FIGURE90.SANCARLOALLEQUATTROFONTANE STANDINGONTHESHOULDERSOFGIANTS:DOMES FIGURE93.DOMEINTERIOR OFTHEBLUEMOSQUE AlsoofIslamicinspiration,istheSultanAhmedMosque,thelargermosqueina complexofseveralknowncollectivelyastheBlueMosque,namedforthebluetiles adorningthewallsofitsinterior.Completedin1616,themosquewasconstructed neartheacclaimedHagiaSophia,andmuchofitsinterior,especiallyitsdome construction,wasinfluencedbythearchitectureoftheearlyChristianchurch.The crowningcircular,masonrydomeoftheBlueMosque,showninFigure92andFigure 93,hovers130feetoveracentralprayerhallandboastsaneightyfootdiameterspan. Thecentraldomeissupportedbyfoursemidomes,whichare,inturn,supportedby threeexedrae,smaller,semicircularhalfdomesrecessedinto,andthereby undulating,abuildingsfaçade.Thereare28windowsinthecentraldome,fourteenin eachsemidome,andanotherfiveineachexedrathatfloodthespacewithlight. OtheruniquedomesfoundthroughoutWesternEuropeincludethedomeofthe Alhambra’sSaladelasDosHermanas(Figure94)inGranada,Spain.Thedomeofthis famedroom,completedinthelate1300s,wasconstructedusingthemuqarna,or “stalactite”vaultingoftheIslamicMoors.Tiny,honeycombedcellsvaulttheceiling andnotonlycreateanacousticallyinterestingspace,butalsocompositelycomprise strikinglyintricategeometricpatternstypicallyassociatedwithIslamicarchitecture. Architecturethroughoutthecenturiesdrewheavyinfluencefrompastgenerations, especiallywhenstructureswerebuilttosymbolizecertainideas,evokecertain emotions,orcommunicatecertainagendas.Forinstance,theclassicalRenaissance idealsofarchitecturalorderandproportionwerereemphasizedtimeandtimeagainin religiousandpoliticalarchitecturalcommissions,particularlyduringtheneoclassical periodofpostrenaissancearchitecture.Duringthisperiod,politicalbuildingslikethe ReichstaginBerlin,completedin1894,wereconstructedintheneoclassicalstyleto communicatetheprinciplesoffreedom,equality,anddemocracy.Furthermore,itis unmistakable,ascanbeseeninFigure95onthenextpage,thatthe1757Parisian churchofSainteGenevieve,nowknownasthePantheon,wasdesignedtohavethe façadeoftheRomanPantheonandthedomeofBramante’sTempietto,thus reinforcingtheinfluentialnatureofarchitectureasaneffectivereligiousandpolitical symbol–amediumbywhichtocommunicatemeaninganddivinerightofempirical power–thesamethathavetranscendedepochs. FIGURE94.SALADELASDOSHERMANASMUQARNADOME PAGE 23 FIGURE92.BLUEMOSQUE STANDINGONTHESHOULDERSOFGIANTS:DOMES Sincetheindustrialrevolution,architectsanddesignersofmoderndomestructures havereplacedmasonrywithnewmaterials,likeglass,metal,andconcrete,inorderto achievenovelstructuralforms.TheaforementionedReichstag,showninFigure96 throughFigure99,forexample,isamoderndomemadeofglassandsteel.This particulardomeisa1992replacementtoasimilarglassandironworkstructurethat wasdestroyedpartlybyfirein1933.Itsawadditionaldestructionduringthelastfew daysofWorldWarII.Alarge,reconstructedglasscupolasitsatoptheroof.Its transparencygivesvisitorsachancetoseeinsidetheparliamentchambersbelow,in linewiththegovernmentalmandatethattheGermanpeoplecanalwayslooktosee whattheirpoliticiansareupto.Naturallightradiatesdowntotheparliamentfloor,and alargeshieldtracksthemovementofthesun,shieldingsunlightwhichmightblind thoseinthechambersbelow. Theintricatelatticeworkofsteelandglassisreminiscentofthecofferingpatternsof ancientdomes,liketheRomanPantheon.Otherbuildingswithsimilar,modernlattice structureswillbeexploredinalaterchapter,aswilllongspannedstructuresachieved bytheuseofconcreteandothernovelconstructionmaterials. Althoughthelastfewbuildingsdiscusseddidnotachievemonumentallyimpressive spans,perse,theyarestillnoteworthyinanexplorationofarchitecturalstyle, influence,form,andmaterialcomposition.Thediscussionofdomes–theancient marvelsandtheiconicstructuresoftheItalianRenaissance–wasthuslycenteredon thepreIndustrialRevolutionconstructionofwoodandmasonrystructures.Modern physics,mathematicsandstructuralmechanics,aswellasthediscoveryofmodern constructionmaterialsandtechniques,gaverisetonewforms,newwaysofbuilding, andnewarchitecturesthatcametodefinethepostIndustrialageofhumancivilization. FIGURE95.PANTEON FIGURE99.SUNSHIELDINTHEDOMEOFTHEREICHSTAGBUILDING FIGURE97.DOMEOFTHEREICHSTAGBUILDING FIGURE98.DOMEOFTHEREICHSTAGBUILDING FIGURE96.REICHSTAGBUILDING PAGE 24 STANDINGONTHESHOULDERSOFGIANTS:DOMES SHELLS&HYPERBOLOIDS Forcenturiesarchitectureandstructurewasatanextremedisadvantage, constantlystrugglingwithmaterialinefficienciesandconstructionlimitations.For modernbuilders,theRomanPantheon,shownagaininFigure100,ismorethan justaniconicpieceofancientarchitecture;itsymbolizeswhatwasachievable,it representswhatwashumanlyandphysicallypossiblenearlytwothousandyears ago,and,ineffect,itsignifieswhatwasinherentlylostfortwomillennia–the knowledgeofthemostversatileconstructionmaterialknowntoman–concrete. Onlysincethemodernrediscoveryofconcretehavedesigners,architects,and buildersbeenabletochallengethebarsetbytheancientRomans.Aftera1500 yearhiatus,modernconcrete,initsbrief175yearhistory,hasbecomethemost widelyusedconstructionmaterialintheworld,andonlyrecentlyhavewe,like theRomans,beenabletomarvelatourownworksofmodernengineering. Concreteismultitalented.Itcanbemolded,strengthened,reinforced,and formedintoanydesirableshape.Itcanbeadjustedforawidearrayof applications,and,moreover,theincorporationofwastematerialsandbyproducts fromotherindustriesactuallyimprovetheperformanceoftheconcreteitself.No wonderconcreteisthemostutilizedconstructionmaterialinthemodernday! Beforethemassapplicationofconcreteasastructuralmaterial,aspreviously mentioned,architectsandbuildershadtorelyonstonemasonsandbricklayersto achievecomplex,undulatingsurfacesintheirdesign.ThefamousworkbySpanish architectAntonioGaudichallengedtheskilllimitsofstonemasonsinhisdesigns. Forexample,hisCasaMila(Figure101andFigure102),builtinBarcelonaaround 1907,hasawavy,masonryfaçade,characteristicofsanddunesorcavelike honeycombs.TheworkisbetterknownasLaPedrera,whichmeans“TheQuarry” inthelocalSpanishdialectofCatalan.Thismountainofstonerequiredthateach blockbecut,carved,andsculptedintotheexactshape–aprocessthatis extremelytimeandlaborintensive. Gaudi’smasterpiece–theSagradaFamilia–wasdesignedandisbeingcon structedinmuchthesameway.AscanbeinferredfromFigure103,theBasilica, famousforitsorganicdetails,sandcastlelikeappearance,useofintricatevault ingandefficientcatenaryforms,requiresthateachstonebesculptedindepend entlyfromallotherstones.Itcomesasnosurprisethatconstructionbeganin 1882andcontinuestoday.Gaudiissaidtohavejoked,“Myclientisnotina hurry.”However,withtypicaltimedependentconstructionprojects,building moderndaystructuresinthiswayisnevertypicallyanoption.Fortunately,after itsrediscovery,concretehasbecomeviablealternativetomasonryconstruction. PAGE 26 FIGURE101.FAÇADE OFCASAMILA FIGURE102.CASAMILA FIGURE100.PANTHEON FIGURE103.SAGRADAFAMILIA STANDINGONTHESHOULDERSOFGIANTS:SHELLS&HYPERBOLOIDS Whenhardened,concreteachievesamasonrylikequality;however,itsstrength, durability,andworkabilityallowittobeformedintoverythinshellsthatarecapableof bridgingmostexpansivegaps.Onesuchexampleofconcreteinathinshellapplication istheCNITBuildinginParis,France.Uponcompletionin1968,thebuildingboastedthe largestconcreteshellintheworldintermsofsquarefootagecovered.Thetriangular shapedvaultisheldinplacebythreesupports.AsseeninFigure104,Figure105and Figure106,aseriesofparalleldoublethinshellcurvebarrelvaultsareplacedsideby side,whichcountertheoutwardthrusttypicaloftunnelvaultsofthisparticularform, effectivelyutilizingthecompressivestrengthofconcrete. Othersimilarconcreteroofstructuresoflessimpressivespanscanbefoundthroughout WesternEurope.Forexample,theHausderKulturenderWelt,showninFigure107,is locatedinBerlin,Germany.Thismuseum,whichisaffectionatelycalledthe“pregnant oyster”bythelocals,isdedicatedtocelebratingthediversityofthepeoplesand culturesoftheworld.Thestructuralsystemismadeofreinforcedconcrete,andthethin shellroof,itscurvaceousform,isaniconiccitylandmark. Concreteiscelebratedforitsabilitytobemoldedandshapedintoanyform,provided thereissufficientwoodenormetalformworktocradlethematerialasitcures. Economicallimitationsofconstructingformworkhavenarrowedthebreadthof concreteapplications;however,somesupremearchitecturalexamplesexist,which showconcrete’strueflexibilityofform. FIGURE104.CNITBUILDING PAGE 27 FIGURE105.CNITCONCRETE VAULT FIGURE107.HAUSDERKULTURENDERWELT FIGURE106.VAULTINGOFTHECNITBUILDING STANDINGONTHESHOULDERSOFGIANTS:SHELLS&HYPERBOLOIDS Forexample,SantiagoCalatrava’sPalaudelesArtsReinaSofía,whichiscurrentlyunder construction,alongwiththeentirecomplexoftheCiutatdelesArtsilesCienciesin Valencia,Spain,isanoperahouseconstructedoutofthinshellconcreteforms,asseen inFigure108.Anotherbuildingonthesite,ElMuseudelesCienciesPrincipeFelipe,isa sciencemuseum.Itscomplex,curvaceousformcanbenotedinFigure109.Thenautical, organicshapesofCalatrava’sarchitecture,shownexquisitelyinFigure110,couldnotbe achievedwithouttheuniqueformabilityofconcrete. TheOrientStationinLisbon,Portugal,showninFigure111,isyetanotherexampleof Calatrava’saffinitytocreatecomplexforms.Thewhimsicallyformedconcrete,seenin Figure112andFigure113,isstrikinglyreminiscentofthearchitecturalconcretework byLeCorbusierandLuigiNervi.Theconcretebasecombineswithmodernapplications ofsteelandglasstocreateothercurvaceous,natural,organicforms.Thisparticular structureservesasagoodtransitionfromadiscussionaboutconcreteshellstoa conversationaboutundulatingsurfaces,complexforms,andhyperboloidstructures madeofothermaterials. FIGURE111.ORIENTSTATION FIGURE113.ORIENTSTATION FIGURE108.PALAUDELESARTSREINASOPHIA FIGURE110.CIUTATDELESARTSICIENCIES PAGE 28 FIGURE112.ORIENTSTATION FIGURE109.MUSEUDECIENCIES STANDINGONTHESHOULDERSOFGIANTS:SHELLS&HYPERBOLOIDS Ahyperboloid,inastructuralsense,isafancytermthatincludesallshapesand surfacesthatarecurvy,wavyandhighlyandirregular.Pureellipticalhyperboloids givetheshapestonuclearcoolingtowers;however,thesamestructuralprinciples usedtoerectthesestructuresarealsousedinconstructingthecurvaceousformof theSageGatesheadConcertHallinNewcastle,England(Figure114),andthe undulatingsurfacesinthedeconstructivistarchitectureofFrankGehry. ThearchitectureofFrankGehryischaracterizedbyitsseeminglychaoticformand unpredictablecurves–hisarchitectureisneverlinear.HisfamousGuggenheim MuseuminBilbao,Spain,whichwascompletedin1997(Figure115),isnowa universallyrecognizedarchitecturalsymbol.Hiswasoneofthefirststructuresto showcasetitanium,alongwithstoneandglass,asapredominantbuildingmaterial. Hisextensiveuseofcomputersinthedesignandschematicrepresentationofthe structuralsystemswasalsoapioneeringendeavor. Gehryisknownforpushingtheenvelope,especiallyinhissculpturallyabstract approachtoarchitecture.AsseeninFigure116,hisdesignfortheDZBankBuildingin Berlin,Germany,whichwascompletedin2000,containsatypicallyGehry hyperboloidsculpturalform,alongwithatensilegridspaceframeofsteelandglass, whichheusesfortheroofandinteriorcanopy. Thisparticularstructuredemonstratesthecomplexformsandshapesthatcannow beachieved,quiteefficiently,withtheintroductionofnewmaterialsand constructiontechniques.Theunprecedentedabilityforconcretetofitvirtuallyany shape,aswellastheemergingapplicationsofsteelandmetallatticework,hasgiven risetonewformsofstructuralmembersandarchitecturalsurfaces–especiallyinthe areaoflongspansystems. FIGURE114.SAGEGATESHEADCONCERTHALL PAGE 29 FIGURE15.GUGGENHEIMMUSEUM FIGURE116.DZBANKBUILDING STANDINGONTHESHOULDERSOFGIANTS:SHELLS&HYPERBOLOIDS TENSILESTRUCTURES Tentstructuresarenothingnew.Formillennia,manhaseffectivelyutilizedtheform, asdepictedinFigure117,byexploitingthetensilecapacitiesofcables,vines,and skins,toprotectthemselvesfromtheelements.Today,mancontinuestofindusesfor thisparticularstructuralform–fromthemostbasicofapplications,likeshadinga SpanishstreetinSevilla,wheretemperaturescanriseabove100degreesFahrenheit daily(seeFigure118),tomorecomplexapplicationsofpneumaticroofstructures. Similarly,manytensilestructuresareusedasshades,notonlythroughoutWestern Europe,butalsoallovertheworld.Forexample,inthearchedopeningoftheGrand Arch(Figure119)intheLaDefensedistrictofParishangsasuspendedtensilecanvas canopy(Figure120)usedasanartisticarchitecturalelementintheoverall compositionofthebuildingdesign.Itisnotastructuralelement,perse;however,its basicfunction,itsmostfundamentalprinciple,toshadepeople,pairswithan overarchingaestheticpurposeandisemployedeffectivelyinbothregards. Ageneralconcernforprotectionfromthesun,rain,weather,eveninpublicspacesis notanovelconcept.Attheheightoftheirempire,ancientRomanswouldholdpublic spectacles–inthegreatCircusMaximusand,morefamiliarly,theRomanColiseum (Figure121).TheColiseumhadauniqueandinnovativewayofshelteringitsfansfrom theblisteringTuscansun.AsdemonstratedinFigure122,theRomansraisedahoopin thecenterofthearenabyusingpullingtautaseriesoftensionedcablesaroundthe circumferenceofthearenaviapulleys,leversandsheermanpower.TheRomans wouldthenunrolllargetarpsofanimalskinsoverthedesiredareasofthetensioned grid,thuscreatingaprotectiveawningforspectators. FIGURE118.SPANISHSTREETSHADE FIGURE117.SIMPLETENTSTRUCTURE FIGURE119.GRANDEARCHDELADEFENSE FIGURE122.ANCIENTROMANCOLISEUMAWNING FIGURE121.ROMANCOLISEUM PAGE 30 FIGURE120.TENSILESHADESTRUCTURE STANDINGONTHESHOULDERSOFGIANTS:TENSILESTRUCTURES Thistensionhoopideaisstillbeingemployedtodayinmodernsportsarena construction,asseenintheBerlinOlympiastadioninFigure123throughFigure126. Themodernsteelandfabricawningwastheresultofarenovationofthe1936 OlympicStadiumforthe2006WorldCup.Theroofitselfisupheldbyanetworkof lightweightsteeltrusses,supportedbyverythincolumns(tomaximizevisibilityfrom anyseat),andanetworkoffabricandplexiglassisstretchedoverthetrussframe. FIGURE124.SLENDERROOFSUPPORTS FIGURE125.1936OLYMPICRINGS FIGURE126.LIGHTWEIGHTSTEELTRUSS,FABRIC,&PLEXIGLASSROOF FIGURE123.BERLINOLYMPIASTADION PAGE 31 STANDINGONTHESHOULDERSOFGIANTS:TENSILESTRUCTURES FIGURE128.PNEUMATICSTRUCTURE FIGURE127.ALLIANZARENA Modernpneumaticstructures,likeMunich’sAllianzArena,depictedinFigure127and Figure128,employthesametypeofframingsystems.Thesteeltrussframescreateaframe overwhichagridofcablesandfabricarelaid.Thefabricitselfisthenfilledwithair, stiffeningthematrixandprovidingstrength,stability,andinsulationtotheoverallstructure. Fabricroofsareapopularchoiceforsportsarenas,particularlybecauseofeconomicadvan tages.NumerousGermansportsarenascontaintensilefabricroofs,liketheoneshownin Figure129–aniceskatingrinkinMunich,whichemploysacombinationsteeltrussandfab ricroofingstructure.AsimilarcompositesystemwasextensivelyusedbySantiagoCalatrava inhisdesignforthe2004OlympicSportscomplexinAthens—bothinhisVelodrome(Figure 130)andtheOlympicStadium(Figure131). FIGURE129.ICESKATINGRINK PAGE 32 FIGURE130.OLYMPICVELODROME FIGURE131.OLYMPICSTADIUM STANDINGONTHESHOULDERSOFGIANTS:TENSILESTRUCTURES BothofCalatrava’sVelodromeandmainOlympicStadiumemploythesamearchsuspensiontensile netstructurefortheircanopies;however,whiletheVelodromehasafabricroof,themainOlympic Stadiumhasasuspendedroofofplexiglass,whichundoubtedlyechoesthe1972workofFreiOtto– thefamedMunichOlympicStadium. ShowninFigure132,the1972MunichOlympicStadium,oncecompleted,wasaninstantengineering marvel.Theintricateuseoftensionedcables,aswellastherevolutionaryuseofplexiglassasa constructionmaterial,gaveinstantfametoOtto.However,theinnovativeuseofplexiglasswasnot originallyOtto’sdecision.Televisionbroadcastingwas,fromitsinductionintomainstreamculture,a highlyinfluentialmedia.TheMunichOlympicGameswerethefirsttobebroadcasttoaglobal audience.Thus,themediademandedthattheygetadequatesunlightfortheirbroadcasts–atall timesoftheday.Ottohadtofindanalternativetoconventionalfabrics.Hedidso–withplexiglass. Tensilelatticeworkroofingsystems,showninFigure133andFigure134,whileextremelyefficientand economical,arebecominganincreasinglypopularalternativetoconventionalroofstructures.Already, therehavebeenmanyapplicationsofsuchsystemsthroughoutWesternEurope,andtheincreasing needtocoverlargerandlargerspaceshaspromptedtheconstantreevaluation,redevelopmentand refinementoftheseflexiblesystems,andtheirmorerigidcounterparts,spaceframes. FIGURE134.PYLONANDTENSILENETROOF FIGURE133.PLEXIGLASS TENSILENET FIGURE132.1972MUNICHOLYMPICSTADIUM PAGE 33 STANDINGONTHESHOULDERSOFGIANTS:TENSILESTRUCTURES SPACEFRAMES Liketensileframestructures,spaceframesexploitthetensilecapacitiesofmaterialsin gridlikeforms,inlayingthemwithplexiglassorotherdurablematerials.Unliketensile framestructures,spaceframesareinherentlymorerigid,morestable,andmore closelyrelatedtothreedimensionaltrussesratherthantwodimensionalstringand skinconstruction. TheevolutionofspaceframeshasoriginsintheageoftheIndustrialRevolution.The emergenceofmodernmaterials,likeiron,steel,andglass,soonreplacedcommon buildingmaterials,likewoodandmasonry.Thisallowedforlighterstructures,interms ofmaterialquantityandstructuralefficiency,aswellasstructuresfloodedwithnatural light,duetothetransparencyoftheglass. Inspiredbythe1851wroughtironandglassCrystalPalace,atemporarybuilding designedbyJosephPaxtonforLondon’sGreatExhibition,the1861GalleriaVittorio EmanueleIIinMilan,Italy.AsseeninFigure135,thepromenadeiscoveredbyan archingglassandcastironroof,andthecentraloctagonalspaceiscoveredbya similarlyconstructedglassdome.Thismarkedanimportantstepintheevolutionof modernglazedandenclosedspaces. Modernapplicationsofspaceframesrangefromsmallscaleapplications,liketheglass metalframeoftheacclaimedBilbaometroports,Figure136,tothehighlycomplex, curvedroofformsofFrankGehry’sDZBankBuilding.Here,itcanbeseeninFigure 137,thethin,barrelvaultedroofspaceframeisactuallybuttressedfromtheinsideby aseriesofsteelcabletensileties,showninFigure138.Thelowercongrega tionalareaisalsocoveredbyamorerigidspaceframe. Similarapplicationsofthesetypesofframesarepopularforconvertingonceoutdoor courtyardsofmuseumsorpublicspaces.Afewexamplesofthesetypesofapplications canbeseeninFigure139andFigure140,theGermanHistoricalMuseuminBerlin, Figure141,theLouvreMuseumPyramidinParis,andFigure142,theBritishHistory MuseuminLondon.Thisparticulartypeofroofconstructionisthepreferredmethod inthesetypesofapplications;themetalandglassroofeffectivelyintegratenew architecturalstyleswitholderonesofmuchsignificancewithoutdisruptingthe message,symbol,orexperienceoftheexistingstructure. Spaceframesareparticularlyusefulforarchitectswhotendtousestructureas dominantelementsintheirdesign.Inasmuch,spaceframesdonotalwayshavetobe inlaidwithanymaterial.Forinstance,SantiagoCalatravaisknownforderivingmuchof hisinspirationforarchitecturalformsfromskeletalsystemsandnaturalstructures,like thebackbonesofanimals,veinsinplantsandleaves,stalksandstemsofflowers,etc. Calatravaseekstheefficiencyinpurestructuralform;tohim,ifitisfoundinnature,it PAGE 34 FIGURE135.GALLERIAV.EMMANUELEII FIGURE136.BILBAOSUBWAYSYSTEM FIGURE137.DZBANKBUILDING FIGURE139.GERMAN HISTORICALMUSEUM FIGURE141.LOUVREGLASSPYRAMID FIGURE142.BRITISHHISTORYMUSEUM FIGURE138.TENSILEBUTTRESS FIGURE140.GERMANHISTORICALMUSEUM STANDINGONTHESHOULDERSOFGIANTS:SPACEFRAMES hasalreadyevolvedtobeefficient.Someexamplesofhisworks,allofwhichhave previouslybeenmentioned,canbenotedinOrientStation(Figure143andFigure144) andthe2004OlympicComplexinAthens(Figure145). Theuniquetensilecapacityofsteelcables,thestrengthandstabilityofmetals,andthe lightweight,transparentclarityofglazingmaterialsmakesspaceframesaunique, efficient,andsuccessfulstructuralform.Today,aspreviouslymentioned,spaceframes continuetospanremarkabledistances,and,morerecently,theyarebeingformedinto unprecedentedshapes. Ageodesicdome,orsphere,forexample,isanearperfectsphere,basedontriangular trussframeelementsthatformanetworkofgreatcircles,calledgeodesics,which actuallyincreasesinstrengthasitincreasesinsize.Historicallywellknowngeodesic domesincludethe1967MontrealBiosphere,byR.BuckminsterFullerandthe1982 SpaceshipEarthatEpcot,WaltDisneyWorld.Asmallerexampleofacomplete geodesicspherecanbeseeninFigure146andFigure147–LaGeode.Thisspace framesphere,whichwasconstructedin1985,ishometoanImaxmovietheaterinthe ParcdelaVilletteattheCitedesSciencesetdel’IndustrieinParis,France. Geodesicdomesandspheres,alongwiththeintricatemetalandglasslatticeworkof spaceframesandtensilestructureslieatthecuttingedgeofarchitecturalstructural systems.Asfarasconventionalconstructiongoes,concretebeams,steelcolumns, masonryfaçadesandwoodenfloorsmaynotseemuchchange,innovation,or refinementintermsofformandmaterialcomposition;however,inspirationmaybe drawnfromexperimentsinwhichpurelystructuralformsarealteredforreasonsof aestheticsandefficiency,andtheymay,infact,bethedirectsourceofinfluencefor modern,longspan,structuralsystems. Whatformcouldbetterfitthebillthanbridges? FIGURE146.PARCDELAVILLETTE FIGURE143.ORIENTSTATION—BUSSTOP PAGE 35 FIGURE144.ORIENTSTATION FIGURE145.WALKWAY—2004OLYMPICCOMPLEX FIGURE147.LAGEODE STANDINGONTHESHOULDERSOFGIANTS:SPACEFRAMES BRIDGES Bytheirnature,bridgesarepurelystructuralinform.Evolved,efficientdesignsare attributedtoscientificmaterialandmechanicalgenius,ratherthanaesthetic,artistic expression.However,throughoutthehistoryofbridgeengineering,differentforms andtypeshaveemergedthatarebothstructurallyefficientandaestheticallypristine, givingmoderndesignersnumerousoptionsintermsofpossiblestructuralsolutions.All formsservedifferentpurposes–somesmallspanfootbridgestransportalightflowof pedestriansonlytensoffeetacrossariver,whilemoreambitioussuspensionbridges supportseverallanesofheavytrafficseveralmilesalongitsspan.Arisingfromphysical necessity,bridgeshavecometosymbolizethetransferofbeliefs,goods,values,and ideasacrossculturalboundaries,andtheyhavecometorepresentaspiritthat embodiesthephysicalityandspiritualnatureofthesocialnetworksofcivilizations. Theearliestformsofbridgeswerenothingmorethanlogslaidoverrivers,streams,or gorges,tiedwithvinesandfittedwithhandrailsupportsmadeofsimilar,local,organic materials.Withtime,moresubstantialmaterials,likestone,iron,lumber,and,more recently,steelandconcrete,havegraduallyreplacedtherudimentary,temporary bridgesofoldwithmodernmarvelsofcivilengineering. TheinfluenceofmodernbridgedesigncanbetracedtotheancientRomans.As previouslymentioned,theRomanswereexceptionalengineers;theirextensive systemsofroads,aqueducts,andbridgesweremadepossiblebytheirdiscoveryand executionofarchedstructuralsystems.TheRomanroundarch,whichwasdeveloped forbuildingandarchitecturalstructures,wassoonincorporatedintothebuildingof civilinfrastructurelikethePontduGard,thefamousaqueductcrossingtheGardRiver insouthernFrance,constructedinthefirstcenturyA.D.(Figure148).Theaqueduct wasconstructedbystackingtwolowertiersofequalspanarches80feetwide;athird tierofthreesmallermasonryarchescontainedacementlinedchannelusedto transportwater,which,atthetimeofthegreatRomanEmpire,wasasimportantto theRomansasmilitarystrength.Thebridge’spiersareonlyafifthasthickasthearch spanwidth,givingthestructureamuchmoreslender,gracefulsilhouettethanmost otherRomanbridgestructureswhichwerebuiltwithapiertospanlengthratioof1:3. SprawlingRomaninfrastructureledtothespreadofideas,culturalvalues,andeven architecturalformsthroughoutEurope.ManyRomaninspiredmasonryarchbridges, likethePontduGard,stillstandtoday;they,liketheCharlesBridgeinPrague,Czech Republic,(Figure149)arecelebratednotonlyforitsengineeringachievement,but alsoforitshistoricalsignificance.TheCharlesBridge,composedofsixteen30foot masonryarchspans,servedasamajorarteryacrosstheVltavaRiveralongan importanttraderoutebetweenEasternandWesternculturesduringthe15thcentury, bringingeconomyandprosperitytotheonceprovincialmedievaltown. FIGURE148.PONTDUGARD FIGURE149.CHARLESBRIDGE PAGE 36 STANDINGONTHESHOULDERSOFGIANTS:BRIDGES Masonrybrickandstonewereusedalmostexclusively,alongwithtimber,inbridge constructionuntilthedevelopmentofmodernstructuralmaterialsaftertheIndustrial Revolution.ThecantileverstyleForthBridge,picturedinFigure150,wasthefirst bridgeconstructedentirelyoutofsteelandisregardedstilltodayasatremendous structuralengineeringachievement.MuchofthedesignworkoftheForthBridgewas donewithoutprecedent:constructionloadsanderectioninducedstresseswere considered,aswellaswindloads,temperatureeffects,andevenlifecycle maintenancecostswerefactoredintotheoveralldesign. Completedin1890,therevolutionaryrailbridge,whichsuccessfullybridgedEdinburgh andNorthQueensferry,Scotland,shatteredallengineeringrecords,spanningatotalof 1.5milesinlengthovertheFirthofForth(675feetbetweeneachsupport)andraising therailroadtracksapproximately150feetabovethewatersurface.Themassive supportstructuresrestonseparatefoundationsthatwereconstructedascaissons undercompressedair90feetbelowthewaterlevel.Thestructuralmembersofthe bridgewereconstructedoutofsteelandrivetedtogether.Thestructuregetsits “cantilever”namefromthestructuralarmsofsupportsthatextendfromthetowering anchors.Thesearmseachholdupasimplegirderbridge,eachspanning350feet, whichwerebuiltbaybybayontheactualconstructionsite.Thefinalcompletionof thesegirderbridges,whicharenotunliketypicalarchtrussbridges,markedtheendof constructionforthismassivestructureoneyearafterGustavEiffelcompletedhis landmarktowerinParis.SimilarlytotheEiffelTower,showninFigure151,theForth Bridgeisapurestructure–havingnodecorativeparts–andendurestothisdayasa workofstructuralart,asacelebratedlocalicon,andasamasterpieceofhuman geniusandmasteryovertheforcesofnature. WhencomparedtothesimplespannedmasonryarchbridgesofRomantimes,steel archtrussbridges,liketheoneshowninFigure152,demonstratetherealadvantages ofalternatematerialsandtheireffectsonachievingunprecedentedspans.For example,insteadofhavingtobuildwoodenformwork,quarry,cut,andsingularlylay precisestonesinordertoconstruct1020individualmasonryarchestospantheTyne RiverinNewcastle,England,themodern,steelTyneBridge,constructedin1928, successfullybridgesthegapefficientlywithone,singlespan.TheTyneBridgespans 531feetbetweenthegranitepiersupports.Thebridgestructureitselfisaround,steel trussedarchthatsupportstheelevatedroadwayandbridgedeck,whichtowers84 feetabovetheriver,bylightweightsteelsectionsactingassuspensiontensioncables. TheTyneBridge,liketheForthBridge,wassignificantly(andnottomentionuneco nomically)elevatedabovethewatersurfaceleveltoallowfortheuninterruptedpas sageofboatsandships.Althougheffectiveintheirdesign,otherbridgeengineers integratedspecificmechanismsthatallowedforvesseltrafficandportaccesswithout actuallyelevatingthebridgedeckitself. PAGE 37 FIGURE150.FORTHBRIDGE FIGURE151.EIFFELTOWER FIGURE152.TYNEBRIDGE STANDINGONTHESHOULDERSOFGIANTS:BRIDGES AfamousexampleisLondon’sTowerBridge,seeninFigure153.Completedin1894, thiscombinationsuspensionandbasculestylebridgewasoriginallydesignedand builtbySirJohnWolfeBarry.Ratherthaninstallinghandoperatedwinchestoraise andlowerthecantileveredbascules,ashadbeenthecasewithothersimilarbridges, Barrydesignedahydraulicpoweredraisingmechanism,poweredbysteamengines whichraisedandloweredthecantileveredbasculeinaduplicatesystem,thus minimizingpotentialfailures.Inaddition,thebasculeswerecounterweighted,which facilitatedtheraisingandloweringofthetwodrawbridges. Each100footbasculecantileversfromasteelframetowercoveredwithornate Victorianmasonryandexuberantlydecoratedtoharmonizearchitecturallywiththe medievalTowerofLondonthatstandsnearby.Theyrise206feetintotheskyandare linkedbytwo140footwalkways.Theapproachesofthebridge,ascanbeseeninthe figure,weredesignedandbuiltassuspensionbridges,relyingonasystemofsteel tensioncablesthatsupporttheroaddeck. Derivingitsformfromprimitivefootbridgesmadeofvinesandwoodplanks,simple suspensionbridgesarestillbeingconstructedbylayingchordsoflumberorother deckingmaterialdirectlyontopofanchoredtensionedcables,typicallydrapedacross supports.Amodernapplicationofthistypeof“ribbon”bridgeisLondon’sMillennium Bridge,designedandconstructedbyArup,FosterandPartnersfortheyear2000 millenniumcelebration.DepictedinFigure154and155,theMillenniumBridge consistsoftwopiersupports450feetapart,connectedbyashallowaluminumdeck supportedbytensionedsteelcables. Whilethis,andsimilarlyconstructedprimitivefootbridges,aresufficientforlight trafficflow,advancesinmaterialsandinnovationsindesignledtothedevelopmentof themodernsuspendeddecksuspensionbridge.Suspensionbridgesofthistypearea compositesystemofanchoredcablesdrapedovertoweringsupports.Aroaddeckis suspended,butlinked,tothedraped,ribboncablebysmallertensioncables,which safelytransfertrafficloadstothepiers,totheanchoredsupports,andfinally,tothe solidfoundations.Examplesofsuchbridgeincludethe1966Ponte25deAbrilandthe 1973BosphorusBridge.Theformer,locatedinLisbon,Portugal,boastsaspanofover 3300feetbetweensupports.ItisoftencomparedtotheGoldenGateBridgeinSan Francisco.Thelatter,locatedinIstanbul,Turkey,connectsthecontinentsofEurope andAsiabyasimilar3500footspan,whichsupportsanaerodynamicbridgedeckwith zigzagsuspensioncables. ThePonte25deAbrilandtheBosphorusBridgetowersareuniqueintheirstructure andresponsetoaestheticconsiderations.Forstructuresthatspanmorethan3000 feet,greatimportanceisplacedonminimizingcostbyminimizingmaterialweightand quantity.Ineffect,manysuspensionbridgetowerdesignsemphasizetheminimization ofcost,resultinginthereplacementofrigidbeamswithlighter,flexiblecrossbracing. Havingbeendesignedwitheconomyinmind,thetowerstructuresofthePonte25de Abrilwereconstructedwithextensivecrossbracing,and,ineffect,theuppermost PAGE 38 FIGURE153.TOWERBRIDGE FIGURE154.MILLENNIUMFOOTBRIDGE FIGURE155.MILLENNIUMBRIDGESUSPENSIONCABLES STANDINGONTHESHOULDERSOFGIANTS:BRIDGES beamsofthetower,whichcanbeseeninFigure156,werealsominimizedinorderto maintainaestheticharmonywiththeothercrossbracingelements. TheBosphorusBridge,ontheotherhand,boastsa“cleanlook”design,inwhichno crossbracingisused.Thetowers,seeninFigure157,actuallyhavethreerigidbeams thatriseabovetheroaddeck;however,thespacingofthebottomtwobeamswas reduced,andwebmemberswereinsertedbetweenthemsothatthetowerslookasif theyonlyhavetwobeams.Reducingthevisuallyrecognizablenumberofbeams resultedincleaner,sleekertowersandanoverallbridgedesignthatvaluedaesthetics ratherthanmaterialefficiencyandeconomy. Akintothesuspendeddecksuspensiondesignisthecablestayedbridgeform.A typicalcablestayedbridgeemploysthesamestructuralprinciplesasthesuspension bridge–abridgedeckissuspendedandstayedinplacebytensionedcables,which directthetrafficloadtothetowerpiersandfoundations.Theonlydifferencebetween thesetwotypesofbridgesisthatcablestayedbridgesaredirectlyattachedtothepier supports,insteadofattachedtoaribbon,suspensioncabledrapedoverthem,asin suspensionbridgedesign.TheVascodaGamaBridgeinLisbon,Portugal,shownin Figure158,wascompletedin1998.Ithasamaximumspanbetweenthesupportsof 1378feet,and,togetherwiththeattachedviaduct,theVascodaGamaBridgeremains thelongestbridgestructureinEurope. Anincreaseinmaterialefficiencyandtherefinementofbridgeformsthroughout historyhaveledtothedesignandconstructionofveryinnovativestructures.Inthe remainingexamples,fundamentalbridgeforms–cantilever,suspension,cablestayed, arch,truss–havebeenintegrated,combined,andredefinedtoproduceveryunique, efficient,andaestheticstructuralsystemswhichhavechallengedandrevolutionized therudimentsofmodernbridgedesign. TheGatesheadMillenniumBridge,whichspanstheRiverTynejustafewyardsup streamfromtheTyneBridgeinNewcastle,England,isacombinationarchsuspension tiltpedestrianandcyclefootbridge,whichtiltstoaccommodatesmalltomedium sizedpassingwatercraft.Completedin2000tocommemoratethemillennial celebration,thefootbridge,seeninFigure159,isamovablebridgewhichrotatesvia hydraulicramsabouthinges(Figure160)atitsfixedendpoints,ratherthanbeinglifted orbended,aswithtypicaldrawbridgestructures.Thisstructure,whichspansa440 feet,rotatesasarigidbody;itstwoperpendiculararches,connectedbysteelcables, serveascounterweightstominimizeenergyneededtotilttheentirebridge. AsimilarstructurewasdesignedbySantiagoCalatrava,whichspans230feetacross theRiverNervioninBilbao,Spain.TheCampoVolantinFootbridge,appropriatelynick namedZubizuri,meaning“whitebridge”inBasque,is,liketheGatesheadMillennium, alsoanarchsuspensionbridge;however,thedesignconsistsofasingleinclinedarch thatsupportsacurvedbridgedecksuspendedbysteelcables,whichareintricately connectedtothesupportingarch.Thearrangementofthebridge’sstructuralcompo PAGE 39 FIGURE157.BOSPHORUSBRIDGE FIGURE156.25DEABRILBRIDGE FIGURE158.VASCODAGAMABRIDGE FIGURE159.GATESHEADMILLENNIUMTILTSUSPENSIONBRIDGE FIGURE160.TILTBRIDGEHINGES STANDINGONTHESHOULDERSOFGIANTS:BRIDGES nentsmakesitauniqueexampleofexquisitestructuralart.Builtaspartofacampaign ofurbanrenewal,thebridgeform,similartootherCalatravadesigns,issaidto communicateanapparentdisequilibrium,orrather,afrozenmovement,whichis punctuatedbythestructurallightnessofitsmembers. Sinceitsopeningin1997,theCampoVolantinfootbridge,showninFigure161and Figure162,hasbecomeapopularlinkforpedestriantouriststravelingtothenearby Guggenheimmuseum;however,thelocalswhotraversethebridgedaily,rainorshine, havesomecomplaints.Thebridgedeck,madeoftranslucentglassblocks,becomes veryslipperywhenwetandoftenposesasafetyissueforthehumidmarineclimateof theVizcayanprovince.Nevertheless,itselegantformwillalwaysserveasymbolic purpose,physicallyrepresentingthecity’scommitmenttourbanrenewal. AnotherexampleofanarchsuspensionbridgeistheBarquetaBridgeinSevilla,Spain. Completedin1989,thisbridge,showninFigure163andFigure164,spans550feet acrosstheAndalusianGuadalquivirRiver.Themainsteelarchsupportsametalbridge deckbyhighstrengthsteelcables.Thearchiscenteredandsupportedbyfourflanking “limbs”whichbalanceonslenderconcretepiers.Theformisskeletallyorganicin nature,characteristicoffishbonesorspinesofreptilesandothercreatures. TheworkofCalatravaismarkedbyanaffinityfororganicform.Famousnotonlyfor hisinnovativecreativityinspatialarchitecture,butalsoforhisefficientlyelegant bridgestructures,Calatravagivesnewdefinitiontoform,compositionandstructural art.Forexample,thedesignsforhis1987BacdeRodaBridgeandhis1995Alameda Bridgepushtheenvelopeofbridgearchitecturalformbycombiningdifferent structuralsystemsinuniqueandinnovativeways. TheBacdeRodaBridge,showninFigure165andFigure166,wasdesignedasaarch suspensionbridgewithtwinsetsofleaninginclinedandsplitarches,joinedattheir apex,whichsupportthepedestrianandvehiculartrafficdeckbyhighstrengthsteel cables.Thecombinationconcretefoundationwithsteelarchstructure,which progressivelydiminishesinsizeandweightasitrisesdemonstratesCalatrava’s adherencetoa“hierarchyofmaterialandform.”TheBacdeRodaBridgespans420 feetwhichlinkstwoprominentstreetsinadrearBarcelonasuburb. Constructedoverexistingrailwaylines,thebridgelinksthemoreaffluentcommunities withthemoredeprived.Thebridgemeetstheaestheticchallengesofitslocation, creatinganattractivepromenadeacrosstheformernoman’sland.Oneofthefirst bridgestocontributetohisworldrenownedreputation,therecognizableformisa testimonytoCalatrava’stheory,aswasliketheCampoVolantinfootbridge,that outlyingurbanareascanindeedberegeneratedbysymbolicintervention. TheAlamedaBridgewasdesignedandbuiltin1995asanarchhollowboxbridge.This uniquestructure,whichspans430feetacrossthenowdivertedRiverTuriain Valencia,Spain,supportsabridgedeckbysteelgirdersconnectedtoasingle,steel PAGE 40 FIGURE161.CAMPOVOLANTINBRIDGEDETAIL FIGURE162.CAMPOVOLANTINFOOTBRIDGE FIGURE163.BARQUETABRIDGEDETAIL FIGURE164.BARQUETABRIDGE FIGURE165.BACDERODABRIDGEDETAIL FIGURE166.BACDERODABRIDGE STANDINGONTHESHOULDERSOFGIANTS:BRIDGES archinclinedat30degreeswhichactsasacantileveredcounterweightforthevariable trafficload.Atalevel45feetbelowthebridgedeck,thedryriverbedisnowhometoa communityparkthatstretchesfromtheAlamedaBridge,whichispicturedinFigure167 andFigure168,totheeasternedgeofthecity,neartheCiutatdelesArtsiCiencies. OneofthemostcelebratedofallCalatravabridgesisthefamedAlamilloBridgein Sevilla,Spain.Knownbyitscharacteristiccantileversparcablestayedstructuralsystem, showninFigure169,Figure170andFigure171,thebridge,completedin1992forthe UniversalExposition,consistsofa460foothighsinglesteelcladdedconcretepylon, which,atanangleof58degrees(thesameangleastheGreatPyramidofCheops) counterbalancesa650footspanbridgedeckwithtwoparallelsetsofthirteensteel cables.Calatravaperformedequilibriumexperimentsontheuniquecantilevered structureusingcubeweightsandwires.Theoriginalintentofthe’92Expocomplex calledforthedesignoftwosymmetricbridges;however,thesingularAlamilloBridge has,byitself,becomeabelovedcityicon,representingtheambitionandhigh aspirationsofSevillainhostingtheworldexposition. Elegant,pureexpressionofstructuralform,thebridgesofSantiagoCalatravanotonly demonstratethemeansbywhichestablishedstructuralsystemscanberedefined,but alsoserveasartistic,technical,andinventiveinspirationforthenextgenerationof architectsandstructuralengineers. FIGURE167.ALAMEDABRIDGE FIGURE168.ALAMEDABRIDGE FIGURE170.SPARCANTILEVER FIGURE171.SPARCANTILEVER FIGURE169.ALAMILLOBRIDGE PAGE 41 STANDINGONTHESHOULDERSOFGIANTS:BRIDGES AFTERWORD WhenIclosemyeyes,Iamthereagain–sittingatopacamelatthebaseoftheGreat PyramidsofGiza,sweatinginsidethedoubleshelldomeofBrunelleschi’sRenaissance masterpiece,standing,shivering,aloneattheNorthQueensferrycape,gazingatthe powerandmajestyofthebridgespanningtheFirthofForth. Icheckcompulsivelyformytatteredpassport,mycamera,myiPod,andmywornand weathereddebitcard.Ihaveonaredbackpack,mySt.Christopher’smedal,andmy belovedbrownCrocs.Isit,clutchingapenandmygreatestsouvenir–aleatherbound journal–andIbegintowrite,“Noone…noonewilleverbelievethethingsthatIhave done…thethingsIhaveseen…theplacesIhavebeen…” Anditbringsasmiletomyface. Inretrospect,myincredibleitinerarywasquiteextensiveandslightlyoverambitiousto saytheleast.Isoughttovisitmorethan10countries,inupwardsof30cities,andover 80structuresduringmy70daytriptoEuropeandpartsoftheMiddleEast.Needlessto saymyschedulewasrigorous,mytimeframestrict,myroomforerror,small–butIdidit all,withlittlechangeoralterationtotheoriginal,proposeditinerary. SomeplacesweremorefascinatingthanIevercouldimagine.Forexample,becauseI wassointriguedbythecharm,history,andcultureofthecity,Imorethandoubledthe lengthofmystayinBerlin.Others,likeMilanwerealittlelesssatisfyingintermsof architecturalinspiration.AlthoughIstuckrelativelywelltomysemirigiditinerary,Ihad theperfectamountofflexibilitybuiltintomodifyandadaptmyscheduletofitmyown interestsinresponsetothedynamicsofthelocalcultures. Thesummerof2007wasnothingshortofextraordinary.Although,priortomydeparture Ihadalittleexperiencetravelingabroad,therewasnothingtopreparemeforwhatwas tocome.Iknewthesummerwouldbethrilling–physicallyandvisuallyexciting–little didIknowthatit,too,wouldbemorespiritualthanIeverthoughtpossible. Muchtomydelight,whileexploringsomecities,Ifoundmostpreciousarchitectural jewelsthatdidnotblipontheradarwhenformingmyoriginalitinerary.Ihadbegunwith theintentionofsolelystudyinglongspanstructuralsystems;however,Ifounditalmost criminaltonegatetheotherarchitecturalandstructuralmasterpiecesinmyfinalreport thatIhadencounteredalongtheway. Indoingso,myreport,originallytitled,“ToBridgeAGap”wasrenamedtoreflectmy newfoundhumility,indebtedness,anduttermostenthusiasmforwhatIhavestudiedand PAGE 42 whatIaspiretodo.Weinthearchitecturalprofessionaretrulystandingonthe shouldersofgreatgiants–andifIdo,infact,seefurther,itisonlybecauseofthem, theirstructures,andtheircontributionstothegreathistoriesofarchitecture. IwishtothanktheSOMFoundationforthistrulyremarkable,onceinalifetime opportunity.Iwill,indeed,beforevergratefulforyourgenerosity,kindness,and relentlesssupport.Icomeawayfromthisexperiencewithnewknowledge,neweyes, andnewhopethatImayalsosomedayjointheranksofthosewhohavegonebefore me,andIcannothelpbutdelightinthefactthattheFoundation,too,willgrantthis uniqueopportunitytoyetanotherdeservedstudent. Inessence,historyisagainrepeatingitselfasIbegintoclimbupontheshouldersof architecturalgiantswithaspirationsthatItoo,willpenmyownhistoricallegacyand leavebehindmyownchapterinthehistoryofarchitecture–achapterofcherished stories,celebratedsongs,andepicpoemsthatwillberenowned,retold,andhopefully rememberedforgenerationstocome. —Wil STANDINGONTHESHOULDERSOFGIANTS:AFTERWORD LISTOFSTRUCTURES UNITEDKINGDOM GERMANY St.Paul’sCathedral WestminsterAbbey BritishHistoryMuseum TowerBridge MillenniumBridge GatesheadMillenniumBridge TyneBridge SalisburyCathedral Stonehenge FirthofForthBridge 44 45 46 47 48 49 50 51 52 53 St.VitusCathedral CharlesBridge 54 55 GREECE 2004OlympicStadiumComplex TheParthenon TheErechtheum TheTempleofDionysus PiraeusRailwayStation 56 57 58 59 60 EGYPT GreatPyramidsofGiza SteppedPyramidofDjoser EdfuTemple TempleofKarnak LuxorTemple TempleofQueenHatshepsut TempleofAbuSimbel 61 62 63 64 65 66 67 PORTUGAL AEGTurbineFactory HausderKulturenderWelt 1936Olympiastadion DZBankBuilding GermanHistoricalMuseum Reichstag Frauenkirsche AllianzArena 1972OlympicStadiumComplex 71 72 73 74 75 76 77 78 79 ITALY CZECHREPUBLIC TURKEY 25deAbrilBridge OrientStation VascodaGamaBridge PAGE 43 68 69 70 PonteVecchio SantaMariadelFiore St.MinatoalMonte GalleriodeVittorioEmmanuelII PisaCathedral&Baptistery SantaMariadellaSalute St.Mark’sBasilica RialtoBridge ArchofConstantine ArchofSeptimiusSeverus ArchofTitus BasilicaofMaxentius Coliseum MausoleumofAugustus Pantheon Sant’AndreaalQuirinale SanCarloalleQuattroFontane St.Peter’sBasilica Tempietto TempleofHercules TempleofPortunus Trajan’sForum 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 HagiaSophia BosphorusBridge BlueMosque 102 103 104 SPAIN BacdeRodaBridge CasaMila 1992OlympicComplex BarcelonaPavilion SagradaFamilia CampoVolantinFootbridge GuggenheimMuseum BilbaoSubwaySystem LaAlhambra AlamilloBridge BarquetaBridge SevillaCathedral AlamedaBridge CiutatdelesArtsiCiencies ValenciaCathedral 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 FRANCE PontduGard ChartresCathedral CNITBuilding LeGrandeArch St.DenisBasilica ArcdeTriomphe EiffelTower LaMadeliene LouvreMuseum NotreDameCathedral Panteon ParcdelaVillette St.Chappelle 120 121 122 123 124 125 126 127 128 129 130 131 132 STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY ST.PAUL’SCATHEDRAL PAGE 44 LONDON UNITEDKINGDOM STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY WESTMINSTERABBEY PAGE 45 LONDON UNITEDKINGDOM STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY BRITISHHISTORYMUSEUM PAGE 46 LONDON UNITEDKINGDOM STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY TOWERBRIDGE PAGE 47 LONDON UNITEDKINGDOM STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY MILLENNIUMBRIDGE PAGE 48 LONDON UNITEDKINGDOM STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY GATESHEADMILLENNIUMBRIDGE PAGE 49 NEWCASTLE UNITEDKINGDOM STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY TYNEBRIDGE PAGE 50 NEWCASTLE UNITEDKINGDOM STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY SALISBURYCATHEDRAL PAGE 51 SALISBURY UNITEDKINGDOM STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY STONEHENGE PAGE 52 SALISBURY UNITEDKINGDOM STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY FIRTHOFFORTHBRIDGE PAGE 53 NORTHQUEENSFERRY UNITEDKINGDOM STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY ST.VITUSCATHEDRAL PAGE 54 PRAGUE CZECHREPUBLIC STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY CHARLESBRIDGE PAGE 55 PRAGUE CZECHREPUBLIC STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY 2004OLYMPICSTADIUMCOMPLEX PAGE 56 ATHENS GREECE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY THEPARTHENON PAGE 57 ATHENS GREECE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY THEERECHTHEUM PAGE 58 ATHENS GREECE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY THETEMPLEOFDIONYSUS PAGE 59 ATHENS GREECE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY PIRAEUSRAILWAYSTATION PAGE 60 PIRAEUS GREECE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY GREATPYRAMIDSOFGIZA PAGE 61 GIZA EGYPT STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY STEPPEDPYRAMIDOFDJOSERCOMPLEX PAGE 62 CAIRO EGYPT STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY EDFUTEMPLE PAGE 63 EDFU EGYPT STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY TEMPLEOFKARNAK PAGE 64 LUXOR EGYPT STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY LUXORTEMPLE PAGE 65 LUXOR EGYPT STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY TEMPLEOFQUEENHATSHEPSUT PAGE 66 LUXOR EGYPT STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY TEMPLEOFABUSIMBEL PAGE 67 ABUSIMBEL EGYPT STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY 25DEABRILBRIDGE PAGE 68 LISBON PORTUGAL STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY ORIENTSTATION PAGE 69 LISBON PORTUGAL STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY VASCODAGAMABRIDGE PAGE 70 LISBON PORTUGAL STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY AEGTURBINEFACTORY PAGE 71 BERLIN GERMANY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY HAUSDERKULTURENDERWELT PAGE 72 BERLIN GERMANY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY 1936OLYMPIASTADION PAGE 73 BERLIN GERMANY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY DZBANKBUILDING PAGE 74 BERLIN GERMANY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY GERMANHISTORICALMUSEUM PAGE 75 BERLIN GERMANY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY REICHSTAG PAGE 76 BERLIN GERMANY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY FRAUENKIRSCHE PAGE 77 DRESDEN GERMANY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY ALLIANZARENA PAGE 78 MUNICH GERMANY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY 1972OLYMPICSTADIUMCOMPLEX PAGE 79 MUNICH GERMANY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY PONTEVECCHIO PAGE 80 FLORENCE ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY SANTAMARIADELFIORE PAGE 81 FLORENCE ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY ST.MINIATOALMONTE PAGE 82 FLORENCE ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY GALLERIODEVITTORIOEMMANUELEII PAGE 83 MILAN ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY PISACATHEDRAL&BAPTISTERY PAGE 84 PISA ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY SANTAMARIADELLASALUTE PAGE 85 VENICE ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY ST.MARK’SBASILICA PAGE 86 VENICE ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY RIALTOBRIDGE PAGE 87 VENICE ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY ARCHOFCONSTANTINE PAGE 88 ROME ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY ARCHOFSEPTIMIUSSEVERUS PAGE 89 ROME ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY ARCHOFTITUS PAGE 90 ROME ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY BASILICAOFMAXENTIUS PAGE 91 ROME ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY COLISEUM PAGE 92 ROME ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY MAUSOLEUMOFAUGUSTUS PAGE 93 ROME ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY PANTHEON PAGE 94 ROME ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY SANT’ANDREAALQUIRINALE PAGE 95 ROME ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY SANCARLOALLEQUATTROFONTANE PAGE 96 ROME ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY ST.PETER’SBASILICA PAGE 97 ROME ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY TEMPIETTO PAGE 98 ROME ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY TEMPLEOFHERCULES PAGE 99 ROME ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY TEMPLEOFPORTUNUS PAGE 100 ROME ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY TRAJAN’SFORUM PAGE 101 ROME ITALY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY HAGIASOPHIA PAGE 102 ISTANBUL TURKEY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY BOSPHORUSBRIDGE PAGE 103 ISTANBUL TURKEY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY BLUEMOSQUE PAGE 104 ISTANBUL TURKEY STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY BACDERODABRIDGE PAGE 105 BARCELONA SPAIN STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY CASAMILA PAGE 106 BARCELONA SPAIN STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY 1992OLYMPICCOMPLEX PAGE 107 BARCELONA SPAIN STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY BARCELONAPAVILION PAGE 108 BARCELONA SPAIN STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY SAGRADAFAMILIA PAGE 109 BARCELONA SPAIN STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY CAMPOVOLANTINFOOTBRIDGE PAGE 110 BILBAO SPAIN STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY GUGGENHEIMMUSEUM PAGE 111 BILBAO SPAIN STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY BILBAOSUBWAYSYSTEM PAGE 112 BILBAO SPAIN STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY LAALHAMBRA PAGE 113 GRANADA SPAIN STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY ALAMILLOBRIDGE PAGE 114 SEVILLA SPAIN STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY BARQUETABRIDGE PAGE 115 SEVILLA SPAIN STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY SEVILLACATHEDRAL PAGE 116 SEVILLA SPAIN STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY ALAMEDABRIDGE PAGE 117 VALENCIA SPAIN STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY CIUTATDELESARTSICIENCIES PAGE 118 VALENCIA SPAIN STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY VALENCIACATHEDRAL PAGE 119 VALENCIA SPAIN STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY PONTDUGARD PAGE 120 AVIGNON FRANCE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY CHARTRESCATHEDRAL PAGE 121 CHARTRES FRANCE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY CNITBUILDING PAGE 122 PARIS FRANCE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY LEGRANDEARCH PAGE 123 PARIS FRANCE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY ST.DENISBASILICA PAGE 124 PARIS FRANCE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY ARCDETRIOMPHE PAGE 125 PARIS FRANCE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY EIFFELTOWER PAGE 126 PARIS FRANCE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY LAMADELIENE PAGE 127 PARIS FRANCE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY LOUVREMUSEUM PAGE 128 PARIS FRANCE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY NOTREDAMECATHEDRAL PAGE 129 PARIS FRANCE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY PANTEON PAGE 130 PARIS FRANCE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY PARCDELAVILLETTE PAGE 131 PARIS FRANCE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY ST.CHAPPELLE PAGE 132 PARIS FRANCE STANDINGONTHESHOULDERSOFGIANTS:PHOTOGALLERY
