STRUCTURAL DESIGN BASIS FOR HIGH-RISE RESIDENTIAL BUILDINGS

STRUCTURALDESIGNBASISFORHIGH-RISE

RESIDENTIALBUILDINGS

Bachelor’sthesis

Hämeenlinna,ConstructionEngineering

Sixthsemester2017

NikolaiMenzhinskii

ABSTRACTDegreeprogrammeinConstructionEngineeringVisamäkiAuthor NikolaiMenzhinskii Year2017Subject Structuraldesignbasisforhigh-riseresidentialbuildingsSupervisors TapioKorkeamäki,AleksiPöyhönenABSTRACT

Thepurposeof thisBachelor’s thesiswas tostudy thestructuraldesignforhigh-riseresidentialbuildings.ThethesiswascommissionedbyPöyryOy Infrastructure Real Estate Design unit. The main aim was to makebasicstabilitycalculationsbasedonthemain loadsofthestructureandwind load for both directions of a 25-floor height building, which thecompany can compare with their own calculations. The main part ofinformationforthesolutionswastakenfromtheEurocodes,supervisor’sandcompany‘smaterials.Firstly,thehistory,differentframesystemsandmainloadswerediscussed.Thesecondpartwascompletelydedicatedtothecalculations.Basedonthecalculations itwasdiscoveredthatthemostdifficultcasesof the wall calculations were not in the top part of the building. Thecomplicated section appears when the wall does not have enoughessentialnormalforce.Consequently,tensilereinforcementforthewallsneedstobedone.

Keywords High-rise,building,load,calculation.Pages 41pages

CONTENTS

1 GENERALINFORMATIONABOUTHIGH-RISEBUILDINGS............................................1

1.1 Needsforhigh-risebuildings..............................................................................11.2 Structuraldesignofhighrisebuildingsnowadays..............................................2

2 FRAMESYSTEMS.........................................................................................................4

2.1 Shearwallssystem..............................................................................................42.2 Rigidframes........................................................................................................52.3 Coreandoutriggersystems................................................................................62.4 Bracedframesandsheartrusses........................................................................72.5 Staggeredsystem................................................................................................82.6 Tubularsystem....................................................................................................8

3 LOADS........................................................................................................................10

3.1 Verticalloads....................................................................................................103.2 Windvelocityandpressure..............................................................................113.3 Specialrequirementsforthewindload............................................................12

4 GENERALINFORMATIONABOUTTHEPERSONALPROJECT......................................13

4.1 Astructuralsystemofresidentialbuildings......................................................134.2 Cast-in-situfloorslabs.......................................................................................134.3 Walls.................................................................................................................134.4 Examplebuilding...............................................................................................14

5 STABILITYCALCULATIONS.........................................................................................16

5.1 Verticalloads....................................................................................................165.2 Horizontalloads(wind).....................................................................................175.3 Minimizationofverticalloads...........................................................................205.4 Additionalhorizontalload.................................................................................205.5 CalculationofwallstiffnessinthedirectionY..................................................225.6 Calculationoftheforce,whichactingonthewallsinthedirectionY..............255.7 CalculationandcomparisonofM(fall)andM(stab)inthedirectionY.............265.9 CalculationofwallstiffnessinthedirectionX..................................................345.10Calculationoftheforces,whichactingonthewallsinthedirectionX............365.11CalculationandcomparisonofM(fall)andM(stab)inthedirectionX.............37

6 CONCLUSION.............................................................................................................40

REFERENCES...................................................................................................................41

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1 GENERALINFORMATIONABOUTHIGH-RISEBUILDINGS

1.1 Needsforhigh-risebuildings

Theconstructionofhigh-risebuildingswasbeguninthelate19thcentury.Thefirsthigh-risebuildingsappearedintheUnitedStates,andwithinfewdecadestheystartedtobebuiltinWesternEuropeandAsia.InEurope,inthebeginninghigh-risebuildingswerenotbuilttosolveanypracticalspecificneeds,butasatributetothetechnologicalprogressandas an expression of force in society. A new approach to the placing ofhigh-risebuildingsinEuropeancitieswasrequiredwithmedievalcentersand dominance of historical buildings. Then model of concentratedplacingofmulti-storyhouses in thecenter,as it is inUSA,couldnotbeused.ThatiswhythisproblemwassolveddifferentlyinvariousEuropeancountries.Themainreasonsforthewidespreadconstructionofhigh-risehousingisthe high price of land designated for the development and the lack ofspace in cities. That is why high-rise building construction solves bothproblemsatonce.Thisconstructionapproachallowsustoplaceonsmallland sites significant amountof indoor area touse, as for flats, offices,shops,hotelapartments,educationalplacesetc. However,notonlythehighlandpricestimulatedtherapidgrowthofthatconstructionsegment.The construction of multi-story buildings would have been impossiblewithouttherapiddevelopmentofbuildingtechnologies,improvementofbuilding materials and constant searching for new constructiontechnologies, which allow to create high-performance designs at aminimalcost.Thesearchfornewengineeringandcompositesolutionsofthelast50yearshasledtothecreationofnewtypesofbuildings,whicharemorecomfortableandmeetallsafetyrequirements.It should be noted that high-rise buildings are complex technicalconstructions, which require a serious approach in all constructionphases. Despite architectural simplicity multi-story buildings havecomplextechnologicalandspaceplanningsolutions.Ahigh-risebuildinghasnotonlyjustwalls,floorsandhighlyplacedroof,firstofallitisasetof engineering equipment. Even the naming of all systems found inmodern high-rise building can be daunting: heating, ventilation, fireprotection, water supply, sewerage, waste disposal, automation, liftingequipmentetc.Moreover, these systemshave theirowncharacteristicscompared with those used in low-rise buildings. In most cases, it isrequired toput thesesystems inabuildingandestablish theirwork,asevery system can have an impact on the other. Even a qualitativelyconstructed high-rise building requires constant attention to the

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structure itself andall engineering systems. Therefore,multiple sensorsare installed, which constantly deliver information about the technicalsituation.Theconstructionofmulti-storybuildingsrequiresspecialattentiontobepaidtotheproblemofchangingthermalregimeofair,smokeprotectionin case of fire, heat supply, air conditioning, heating, ventilation,automation and control systems, security issues and psychologicaldiscomfort. It requires an unusual approach and original engineeringsolutionstomanagealltheproblemsinthemostcases.There are fewexamples to understandbetter all the complexity of thehigh-rise building. Traditional heating and water supply systems underthegravityinbuildingswithaheightof100metershaveapressuremorethan10atmonthefirstfloor.Eveninthehundred-meterbuildingwaterpressure will break any normal system. But gravity affects equally onother building’s life-support systems. Gravity affects the garbagedisposal and sewage. Speed dampers should be installed for thosesystems to reduce the noise. The gravitational force should also beconsidered in the fireprotection system. Waterused toextinguish thefire should flow to the drainage network. Also modern apartmentsshould be waterproofing. Therefore, floors should have a small slope,throughwhichwatercanflowintothegutter,inordernottofilltheroomandbringdowntheceilings.Thedesignand installationofenclosing structures,engineering systemsandsafetysystemsofhigh-risebuildingsrequirespecialattention.Allofthese systemscannotbe installedwithout specific information support,detailed analysis of international experience and help of experts invariousfields.

1.2 Structuraldesignofhighrisebuildingsnowadays

Buildingsarecalledhigh-risetodayiftheirheightismorethan75meters.Those buildings can have different spheres of use: hotels (WMarriottMarquis Dubai), office buildings (Metropolitan Life Insurance CompanyTower), residentialbuildings (Pentominium),universities (MoscowStateUniversity).Usuallyhigh-risebuildingsaremultifunctional,inadditiontothemainpurposeofliving,shops,parkingspots,cinemasandofficesetc.arelocatedthere.There are many countries including USA, which has a significantexperienceinstructuraldesign,constructionprocessandexploitationofhigh-rise buildings. One of the first high-rise building was WoolworthBuilding inNew-York (241m/57 floors),whichwasbuiltmore than100years ago, in 1913. For a long time the highest high-rise building wasEmpire State Building that has 102 floors and the total height is 381m

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(448 m with antenna). Later, World Trade Center in New-York (415m,417m)andSearsTowerinChicago(442m)becamethehighestbuildings.However, nowadays the construction of the highest skyscrapers wasmoved to the East, to the United Arab Emirates, Malasia, Taiwan andChina.Over the last years in big Russian cities such as Moscow and SaintPetersburg plenty of High-Rise Residential buildings were built such as“ScarletSails”(48floors)andNorthvalley(28floors).High-risebuildings,especiallyskyscrapers,havetheirownframespecifics,which distinguishes them fromordinary buildings. Firstly, if the heightincreases sharply, the load on the loadbearing systems increases, too.Thus,somestructuralsystemsweredevelopedtomanagethisproblem:rigidframe,framedtube,shearframe,bracedframe,corestructure,BESopenelementsystemandothers.Thechoiceofthestructuralsystemdependsonmanyfactors.Themainfactorsaretheheightofthebuildingandgeographicconditions,suchasseismicity, soil characteristics,windand snow loads. It shouldbenotedthat according to German researchers, the wind load inmany cases ismore important than seismic effects. One of the highest buildings oftoday, John Hancock Center in Chicago and the International FinancialCenterinTaipeiaremadeonthetrussedtubesystem,inwhichtheouterperimeter walls are rigidly connected to the center tube and furtherstrengthenedbypowerfuldiagonal connections.All thebuilding, in thiscase,worksasarigid,stiffconsole.To reduce vibrations of high-rise buildings under the influence ofwindload, nowadays suspended inertmass iswidely usedon the top of thebuilding.The construction practice shows that rigid systems have a limitedhardness.Itisusefultouseituntil40floors.Framedtubesystemscanbeusedupto50-60floors.Abundledtubecanhandle80-90floors,andifitisneededtoconstructabuildingwithmoreheight,atruss-tubeschemeshouldbeused.Oneofthebasicrequirementsforhigh-risebuildingsmustbeacomplexsecurity requirement, which should ensure useful evacuation ways incrisis situations, fire and anti-terrorist attacks. Also, reliablemonitoringand control of all technical equipment systems, duplication of all life-supportsystemsshouldbeusedinthistypeofbuilding.

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2 FRAMESYSTEMS

Various loadbearing frames can be found for high-story buildings. Thebestsystemischosenaccordingtodifferentfactors,suchastheheightofthebuilding,architecturaldesignandlocation.Thehigherahouseis,themore different constructions are needed to manage all the horizontalloads. If there is a rigid frame building with a height of 50 floors,materialsfortheresistinghorizontalloadsaremorethanforthevertical.Thus,anappropriate framesystemrequiredtoresistall loadsandhaveaneconomicconstructionprocess.Themostcommonstructuralsystemsforthehigh-risebuildingarediscussedbelow.

2.1 Shearwallssystem

Shearwalls systemallowhavingahigh resistance in theirownplane tothehorizontalloads.Shearwallscanbeusedinvariousways.Thefirstvariantistousesystemcolumnswithslabsandshearwalls. Ithasatwicemoreeffectiveheightthanjustcolumnsandslabs.Forexample,abuildingwithcolumns,slabsandshearwallshasaneffectiveheightuptoabout20stories,whereasasystemwith columns and slabs has its effective height up to about 10levels.AshearwallframesystemisshownbelowinFigure1.Shearwallshave to be coupled by setting beams between the shear walls, as isshown inFigure2. It isaveryefficientway toenlarge theresistanceofhorizontal loads of a building. Also, there are a lot of spots to placewindowsanddoors.Tosumup,itiseffectivetoconstructabuildingwiththattypeofframeupto40floors.

Figure1.Illustrationofshearwallsframesystem(Rist,V.C.&SwenssonS.2016)

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Figure2.Illustrationofcoupledshearwalls(Rist,V.C.&SwenssonS.2016)

2.2 Rigidframes

Rigid frames suit mostly for low-height buildings. A rigid frame is astructure of columns and beams with a connection, which resist themoments. A rigid frame system is shown in Figure 3. It manageshorizontalloadsbybendingresistanceofthewholestructure(beamsandcolumns). The sizes of columns are mostly controlled by the bendingresistance,notbyloadingcapacity,duringdesigningphasewithmomentresisting frames. To reduce thehorizontal loaddeflection a componentwithahighbending resistance isneeded.Also,all connectionsmustbedesignedproperlyasinadequateconnectionscancausemajorproblems.Somedeviationintheconnectionanglecancontributetoabiginclineofthewholeconstruction.Thebestmaterialstothosetypesof framesaresteelandconcrete.Themaximumheight for steel isalmost30 floors,whileconcrete structurescan be just 20 floors. If there is a building withmore than 30 stories,there canbea riskof abighorizontal deflection,becauseofwind loadand seismic activity. Also, connection structures in this case are toocomplexandexpensiveinordertoresistbigmoments.

Figure 3. Illustration of the rigid frame system (Rist,V.C.& Swensson S.2016)

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2.3 Coreandoutriggersystems

Shearcolumnsinsidethebuildingformthecorearoundanelevatorshaftand stairways.This corecan resistall the loads:horizontal, vertical andtorsional.Thecoresystemiseffectiveupto45stories.Columnstakealladditionalverticalforces.Amixofrigidframesandshearwallscanbeusedtoconstructahouseupto60floors.Thecoreofshearwallsisaroundtheelevatorandstairways,whereasrigidframesareonexteriorofthehouse.Coreandrigidframesystemsdecreasetheoverturningmomentandhazardforacoreuplift.An outrigger system can be added to the core to raise its bendingresistance. The outrigger system consists of high stiff floors in theconstruction. Outriggers are connected to columns, which are placedalong the perimeter to the ground. When the wind load acts on thestructure,exteriorcolumnsreducethemomentforthecore.Also,therearebeltwallswhichresisttherotationofoutriggers.Belttrussesorwallsareplacedon theperimeterof theoutrigger floor. The core resists theshear and torsional forces, while the outrigger reduces the horizontaldisplacement,becauseofthebending.Thistypeofsystemcanbeusedinbuildingsofupto150stories.

Figure 4. Illustration of the core and outrigger system (Rist,V.C.&SwenssonS.2016)

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2.4 Bracedframesandsheartrusses

Sometimesdiagonal braces in a rigid structure are settled tomake thisrigidframestronger.Bracingsystemsareplacedinsidetheframesystemto manage horizontal forces; namely, it decreases the bending ofcolumnsandgirders.Thissystemismuchmoreeconomicalthanframeswith the moment resistance. Braced frames are often placed in thebuilding core. The braced frame system is efficient up to 40 storybuildings. Two types of bracing system frames are defined: eccentricbracedframesandconcentricbracedframes.Theconcentricbraceframeincludesbracingelementscrossing in thesamepoint.As theconcentricbrace frame is stiff and has a very poor inelastic behavior, it is notappropriate for seismic zones. Whereas in seismic zones it is better tohaveaneccentricbracingsystemframe,asitisstiff,strongandhashighinelastic characteristics of a resisting moment. This frame type isappropriatefor25-30floors.ConcentricandeccentricbracedframesareillustratedinFigures5and6below.

Figure5.Illustrationofconcentricbracedframes(Rist,V.C.&SwenssonS.2016)

Figure6. Illustrationofeccentricbraced frames (Rist,V.C.&SwenssonS.2016)

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2.5 Staggeredsystem

Astaggeredsystemisavariationofthetrusssystem.Usuallythissystemcanbeusedupto25floorsfornarrow,longresidentialbuildings.Thereare trusssystemswhichareplaced inaspecial sequenceoneach floor.This type of frame is illustrated in Figure 7. Those trusses resist thehorizontal loads, whereas columns do not have any bending. Trussesshouldalsohaveopeningsfortheusageofabuilding,byremovingsomediagonalmember.Thestiffmomentframeshouldbeplacedaroundtheopening,toresistloads.

Figure7.Illustrationofastaggeredtrusssystem(Rist,V.C.&SwenssonS.2016)

2.6 Tubularsystem

A tubular system is used forbuildingsofup to60 floors inheight. Thisstructurehastubesaroundtheperimeterofconstruction,whichtakeallhorizontal and vertical loads of a structure. The tube frame is done bycolumnsplacednexttoeachotheraroundtheedgeofthebuilding.ThistypeofstructureisshowninFigure8.

Figure8.Illustrationofthetubularsystem(Rist,V.C.&SwenssonS.2016)

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Tomakeastructurestiffer,externalbracingscanbeadded.Thistypeofstructurewill be calledanexteriordiagonal tube system. It is shown inFigure9.Thistypeofframeiseffectiveupto100floors.

Figure 9. Illustration of an exterior diagonal tube system (Rist,V.C.&SwenssonS.2016)Abundledtubesystemconsistsofconnectedtubes.Thistypeofsystemis shown in Figure 10.This system resists big loads, as tubes areconnectedtogether,therearewidespacingsforwindows.

Figure10. Illustrationofabundled tubesystem(Rist,V.C.&SwenssonS.2016)A tube-in-tube system is obtained, if the core is placed inside the tubeframe structure. There are advantages of both systems, whereas theframeresistsgreatloads.

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3 LOADS

Thestructureofanybuilding isexposedtovarioustypesof loads.Thus,everyconstructionhastomanagewiththeverticalandhorizontal loadsthatarementionedbelow.- Dead load. It includes the selfweight of thewhole structure (load

bearing members, non-structural members and whole installationstructures)

- Liveload.Itincludesthewholeloadfromoccupantsandfurniture.- Snowload.- Lateralload.Itincludesthewindload.AllloadsshouldbecalculatedaccordingtotheinstructionsinEN1991-1-1,EN1991-1-3,EN1991-1-4.High-storyhousesshouldalsobedesignedregarding the special requirements in Eurocodes, which are discussedbelow.

3.1 Verticalloads

InaccordancewithEC1991-1-1,6.2.2(2) the reduction factoran for thelive load in themultiplestorybuildingshouldbedeterminedwithin theformulabelow.

(1)where:n is the number of floors (more than 2) above the loadedstructuralelementsfromthesamecategory.Ψ istakenfromEN1990,AnnexA1,TableA1.1.Reduction factor can also be calculated with the use of the areaaccordingtoEN1991-1-1chapter6.3.1.2(10).abcanbecalculatedwithintheformulabelow.

(2) A0–theconstant,equalsto10m2.A–loadedarea

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3.2 Windvelocityandpressure

EN1991-1-4givesinstructionsforthecalculationofhigh-risebuildingsupto200meters.ThewindloadconcerningEurocodesactsonthestructurestatically and dynamically. While tall buildings have to consider bothpartsof it, asdynamicpart is in chargeof thedynamicnatureofwind,andthestaticaffectsjustasdistributedhorizontalloadofthewind.ThereferencepeakvelocityqpthedynamicandstaticpartswiththehelpofIv(turbulence intensity). cd is considered a dynamic response during thecalculationprocessofstaticsloads.qb-basicvelocitypressurevb-basicwindvelocityρ–airdensity(1.25kg/m3)

(3)qp–peakvelocitypressureIv-turbulenceintensityc0–orographyfactor.Thevaluevariesifthegroundlevelsaredifferentinthatarea,forexamplehillsofcliffs.Itcanbenotconsiderediftheslopeofupwindlessthan30.Thewindvelocityrisesinthatcase.EC1991-1-4A.3.z0–roughnesslength.ItcanbefoundinappendixA.1.

(4)Asimplifiedcalculationversionofqpwhenorographyfactoris1.0.

(5)ce(z)-exposurefactor.ItcanbefoundinFigureA.7EC1991-1-4A.1vm(z)–meanwindvelocityvb–basicwindvelocity

(6)cr(z)–roughnessfactor

(7)

(8)

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z,zo,II–itcanbefoundfromtheEC1991-1-4A.1.

3.3 Specialrequirementsforthewindload

Thewindforcecanbefoundfromtheequationbelow.

(9)

(10)qp(z)–isthepeakvelocitypressure.cf–forcecoefficient.ItcanbefoundinEN1991-1-4section7,8.Aref–referencearea.cs-non-simultaneousoccurrenceofpeakwindpressureonthesurface.cd–vibrationeffecttothestructureduetoturbulence.cscd–shouldbecalculatedtogetherfromthefollowingequation.

(11)Thevalueofcscdshouldbe1forthebuildingsupto15m.Inthecaseofhigh-storybuildings,theEC1991-1-4,AnnexDshouldbeused.

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4 GENERALINFORMATIONABOUTTHEPERSONALPROJECT

Themain part of the project consists of calculation of basic loads andwind loadfor the25storyhigh-risebuilding. CalculationsarebasedonEuro-Codes.

4.1 Astructuralsystemofresidentialbuildings

Residential buildings in Finland usually consist of reinforced concretewalls(shearwallsystem).Cast-in-situ slabs, bearingpartitionwall elements, bearingexternalwallelementsandlightexternalwallelementsarethebasicelementsofthissystem.Thelengthandthicknessofslabscanbechosenwithinthelimitsoftheloadingcapacity.Thissystemgivesthearchitectfreedomtodesigninteriorofthebuilding.

4.2 Cast-in-situfloorslabs

Theheightofacast-in-situslabinresidentialbuildingsisusually300mmwitha20mmconcretetopping.Also,thisheightfrequentlycomesfromtherequirementsofsoundinsulation.Cast-in-situ slab floors are stabilized by means of peripheralreinforcement around the whole floor. The resulting plates transmithorizontal forces (wind, stabilizing, seismic and other loads) to theverticalstabilizingstructuresinproportiontotheirrigidities.

4.3 Walls

Thethicknessofthebearingpartitionwall inashearwallsystemis180mm,itprovidesasupportingsurfacefortheslabs,soundinsulationandvertical load bearing capacity for buildings up to 8 stories. In our case250mm, 275mm, 300mm, 400mm wall thickness was selected for theload-bearingcapacityforallthebuildingfromthe3rdto25thfloor.Usually, the minimum internal wall thicknesses are 200 mm for aloadbearingstructureand80mmfornon-loadbearingwalls.This system is vertically stabilized by walls, which work as fixed-basedcantilevercolumns.If necessary the wall elements can be combined by means of verticaljoints strengthenedwith steel and concrete dowels to form larger andmorerigidunits.Asmuchaspossibleofthetotalverticalloadingshouldbetransmittedtothebracingwalls.Thebestresultsareobtained if the

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wall sections are completely compressed throughout. If tensile stressesarise in the walls due to the action of horizontal forces, verticalreinforcement extending from one wall element to the next must beinstalled, usually in the formof ordinary deformed steel reinforcementbars. If the tensile forces are high, the elements can be connectedtogetherbymeansofprestressingtendons.Bearing walls can be erected either parallel or transverse to thelongitudinalaxisofthebuilding.

4.4 Examplebuilding

Drawingsof theexamplebuilding canbe found inFigure11andFigure12.The following containsbasic technical informationandmaterial aspectsoftheexamplebuilding:

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Figure11.Sidearchitecturalviewofthebuilding

Figure12.3Dsideviewofthewholeconstructioncomplex

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5 STABILITYCALCULATIONS

Thestabilitycalculationsofthebuildingwillbediscussedinthefollowingchapters.

5.1 Verticalloads

Thebasicverticalloadsarediscussedbelow.A. Cast-in-situslabg1=0.5kN/m2 concretetopping20mmg2=7.5kN/m2 Concreteslab300mmq1=2.5kN/m2 liveload*personal-load2kN/m2+lightweightwalls0.5kN/m2 InaccordancewithEC1991-1-1,6.2.2(2)reductionfactorequalsto

an=(2+(25-2)*0,7)/25=0.724ð q1=0,724*2+0,5=1.948kN/m2B. Abearingwallsg3=14.4kN/m *200mmconcreteg4=18kN/m *250mmconcreteg5=19.8kN/m *275mmconcreteg6=21.6kN/m *300mmconcreteg7=28.8kN/m *400mmconcreteC. Anon-bearingexternalwallg8=12kN/m *internallayer80mmconcrete +externallayer80mmconcreteD. Roofq2=7.5kN/m2 *Concreteslab300mmq3=1kN/m2 * Layer above the concrete slab

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5.2 Horizontalloads(wind)

Thebasichorizontalloadcalculationprocesswillbediscussedbelow.ThewindloadiscalculatedaccordingtoSFS-EN1991-1-4:2005.

Figure13.SchematicplanviewA. DirectionY,Floors3-9Fw=cs*cd*cf*qp(n)*Aref (12)Fw=75,513kN cs*cd=(1+2*kp*Iv(zs)*(B2+R2)^0.5)/(1+7*Iv(zs)) (13)cs*cd=0.8875,(Figure14)

Figure14.cscdformultistoryconcretebuildings(SFS-EN1991-1-4:2005)

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λ=1.82*h/b=1.94, (14)Usinginterpolation,asλ=2*h/b,whenh<15andλ=1.4*h/b,whenh>=50d/b=0.58cf=1.4fromtheTable5.2S,5.3.1S,EN1991-1-4qp(32)=(1+7*Iv(zs))*0.5*ρ*vm2(z)=ce(z)*qb (15)

qp(32)=675,28N/m2Iv(z)-turbulenceintensityρ–airdensity1,225kg/m3

vm–basicwindspeed21m/sce=2,5,exposurefactorat32m(figure15)Iv(z)=k1/(c0(z)*ln(z/z0)) (16)k1–turbulencefactorc0–thesurfaceshapefactorz=32m,heightofthebuildingfromthesoillevelz0–roughnessmeasurementqb=0.5*ρ*vb2 (17)

qb=270,11N/m2

Figure15. Illustrationof theexposure factorce(z) forc0=1,kr=1 (SFS-EN1991-1-4:2005)

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Aref=b*h (18)Aref=30*3=90(m2)Fw=cs*cd*c*qp(n)*Aref,windloadforthe1storyheight (19)Fw=75,513(kN)B.

DirectionY,Floor10-25H 81,00 mcs*cd 0,9357

λ 3,78d/b 0,58cf 1,53ce 3,27qb 270,11 N/m2

qp 883,27 N/m2Aref 90,00 m2Fw 113,805 kN

C.DirectionX,Floor3-9

H 32,00 mcs*cd 0,935

λ 3,34d/b 1,71cf 1,2ce 2,50qb 270,11 N/m2

qp 675,28 N/m2Aref 52,50 m2Fw 39,777 kN

D.DirectionX,Floor10-25

H 81,00 mcs*cd 0,9673

λ 6,48d/b 1,71cf 1,25ce 3,27qb 270,11 N/m2

qp 883,27 N/m2Aref 52,50 m2Fw 56,069 kN

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5.3 Minimizationofverticalloads

Thebasicminimizationloadcalculationprocesswillbediscussedbelow.Nd(roof)=30*17,5*(0.9(7.5+1))=4016.25kN (20)Nd(loadbearingwallslevel3-25)=8*4.25*0.9*18+6.325*0.9*18++6.575*2*0.9*28.8+6.575*2*0.9*18+6.325*0.9*18++8.35*2*0.9*21.6+6.05*0.9*18+3.05*0.9*18+10.030*0.9*18++6.3*0.9*18++6.03*0.9*19.8+3.475*0.9*18+8.3*0.9*18++12.3*0.9*28.8+9.05*0.9*18=2810kN (21)Nd(nonloadbearingexternalwall)=30*2*0.9*11,52=622.08kN

(22)Nd(wallslevel3-9)=Nd(loadbearingwallslevel3-25)+Nd(non

loadbearingexternalwall)=3432kN(23)

Nd(wallslevel10-25)=Nd(loadbearingwallslevel3-25)+Nd(non loadbearingexternalwall)=3432kN

(24)Nd(floor)=0.9*8*17.5*30=3780kN

(25)Nd(stairwell)=6*2.94*0.9*0.3*25=114.31kN

(26)

5.4 Additionalhorizontalload

Thevaluesofadditionofhorizontalloadsarebasedontheinclinationofthe vertical loadbearing structures. Additional horizontal loads act oneachflooratthepointsofhorizontalloadaction.Ɵi=αn*αm*Ɵ0 (27)Ɵ0=1/200 (28)αn=2/h0.5 (29)

αn=0.23αn=2/3,as2/3<αn<1.0αm=(0.5*(1+1/m))0.5 (30)αm=0.7416

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m=10,numberofstiffenerwallsƟi=0.002472Hd(roof)=Ɵi*(Nd(walls)+Nd(roof)) (31)Hd(roof)=0.002472*(3432+4016.2)=18.4kNHd(floor3-25)=0.002472*(3780+3432+114.3)=18.11kN (32)Hd(roofdirectionY)=1.5*Fw+Hd(roof) (33)Hd(roofdirectionY)=1.5*113,805+18.4=189.1kN/floorHd(roofdirectionX)=1.5*Fw+Hd(roof) (34)Hd(roofdirectionX)=1.5*56,069+18.4=102.5kN/floor Hd(floor3-9directionY)=1.5*Fw+Hd(floor3-9) (35)Hd(floor3-9directionY)=1.5*75,513+18.11=131.4kN/floorHd(floor10-25directionY)=1.5*Fw+Hd(floor10-25) (36)Hd(floor10-25directionY)=1.5*113.805+18.11=188.8kN/floorHd(floor3-9directionX)=1.5*Fw+Hd(floor3-9) (37)Hd(floor3-9directionX=1.5*39,777+18.11=77.8kN/floorHd(floor10-25directionX)=1.5*Fw+Hd(floor10-25) (38)Hd(floor10-25directionX)=1.5*56,069+18.11=102.2kN/floor

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5.5 CalculationofwallstiffnessinthedirectionY

A construction going from 3-25 floors and roof was taken intoconsideration.ThebasicwallstiffnesscalculationprocessinthedirectionYwillbediscussedbelow.

Figure16.LoadbearingwallsagainstwindloadinthedirectionYa) Wall№1Yn=8,numberofwallsL=80m,heightfromthegroundleveltothetoph=4,25lengthofthewallb=0,25m,widthofthewallE=30000MN/m2

ky=1,2ν=0,3I=b*h3/12 (39)I=1,6m4A=b*h=1,0625m2 (40)

k1y=E/((L3/(3Iy)+(2*(1+ν)*ky*L)/A)) =0,2805MN/m (41)

∑k1y=n*k1x=2,244MN/m (42)

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b) Wall№2Y

n 1 L 80 mh 6,325 mb 0,25 mE 30000 MN/mm2I 5,27 m4A 1,58125 m2ky 1,2 ν 0,3 k2y 0,92214786 MN/m∑k2y 0,92214786 MN/m

c) Wall№3Y


d) Wall№4Y


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e) Wall№5Y


f) Wall№6Y


g) Wall№7Y


25

h) Wall№8Y


5.6 Calculationoftheforce,whichactingonthewallsinthedirectionY

Thebasichorizontal forceactingoneachwallcalculationprocess inthedirectionYwillbediscussedbelow.∑kiy–sumofthewholewallstiffnessνy-deflection∑kiy=∑k1y+∑k2y+∑k3y+∑k4y+∑k5y+∑k6y+∑k7y+∑k8y (43)∑kiy=16,92MN/mThemaximum forcewas taken in that case, which acts on the highestwallandroof.Fy=Hd(roofdirectionY)=189,1kN=0,1891MNνy=Hd(roofdirectionY)/∑kiy (44)νy=0,0115989mQiy=kiy*Fy (45)

Q1y 0,003253568 MNQ2y 0,010695902 MNQ3y 0,019216453 MNQ4y 0,012010283 MNQ5y 0,010695902 MNQ6y 0,034328973 MNQ7y 0,009364427 MNQ8y 0,001203803 MN

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5.7 CalculationandcomparisonofM(fall)andM(stab)inthedirectionY

The basic calculation and comparison process ofM(fall) andM(stab) intheYdirectionwillbediscussedbelow.

Figure17.Schematicplanviewofthebuilding.Calculationoftheforces,whichareactingonthewall№1YcaseAY1)Wall№1YcaseAThe wall with the total length of 17,5m was taken into consideration.Floors,whichweretakeninthosecalculations,are3-25.Howeveritwasdivided into 4 pieces, so the length is 4,25 m from the structuraldrawings.Also,thespanofthespreadload,whichgoesfromthefloor,inthatcaseis5,93*0,5.ai–theheightfromthesoilleveltothepoint,wheretheloadacts(Figure18).H1d=Q1y=20,59kN(Figure18)a3=11m,a4=14m…aroof=81m(Figure18)M(fall)–moment,whichtriestocollapseandoverturnthestructure.M(fall)=Q1y(roofdirectionY)*(a3+…+aroof) (46)M(fall)=3556,15kNmNd(wall4,25m,height11-81m)=g4(wall250mm)*L(4,25m) (47)

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Nd(wall4,25m,height11-81m)=18*4,25=76,5kNNd(roof 4,25m, height 11-81m) = 0,5*L(wall)*L(loading area) * (0,9*(q(concreteslab)+q(topping)) (48) Nd(roof4,25m,height11-81m)=0,5*4,25*5,93*(0,9*(7,5+1))=96,4kNNd(floor8,75m,height11-81m)=0,5*4,25*5,93*(0,9*(7,5+0,5))=90,73kN∑Nd=Nd(roof4,25m,height11-81m)+17*Nd(wall4,25m,height11-81m)+17*Nd(floor8,75m,height11-81m) (49)∑Nd=3775,43kNa–distance fromtheedgeofwall side tomiddlepointofcompressionarea(Figure18).e – distance from themiddle point of compression area to the verticalload(Figure18).∑Nd=0,25*2a*fcd (50)

fcd=17000kN/m2

a=∑Nd/(0,25*2*fcd) (51)a=0,444me=L/2–a (52)e=4,25/2–0,44=1,68mM(stab)=e*∑Nd (53)M(stab)=6345,87kNmM(stab)>M(fall),thosewallsdonotneedtensilerebars.

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Figure18.Schematicsideviewofthecheckedwall

Y2)Wall№1YcaseB

H1d=Q1y 3,25 kNM(falling) 3556,15 kNmNd(wall4,25m) 76,50 kNNda(roof) 134,93 kNNd(floor3-25directionY) 126,99 kN∑Nd 4611,71 kNfcd 17000,00 kNa 0,54 me 1,58 mM(stab) 7297,78 kNm

M(stab)>M(falling)

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Y3)Wall№1YcaseC


M(stab)>M(falling)Y4)Wall№1YcaseD

H1d=Q1x 3,25 kNM(falling) 3556,15 kNmNd(wall4,25m) 76,50 kNNda(roof) 142,65 kNNd(floor3-25directionY) 134,26 kN∑Nd 4779,31 kNfcd 17000,00 kNa 0,56 me 1,56 mM(stab) 7468,77 kNm

M(stab)>M(falling)Y5)Wall№2Y

H1d=Q2y 10,70 kNM(falling) 11690,62 kNmNd(wall6,325m) 113,85 kNNda(roof) 239,03 kNNd(floor3-25directionY) 224,97 kN∑Nd 7693,02 kNfcd 17000 kNa 0,905 me 2,257 mM(stab) 17366,56 kNm

M(stab)>M(falling)

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Y6)Wall№3YcaseA


M(stab)<M(falling)M(stab)<M(fall).Tensilereinforcementisneeded.

Nd(wall6,575) 189,36 kNe2 5,14 mNs 452,82 kNfyd 435,00 N/mm2As 1040,97 mm2

As–areaoftensileneededtoresistM(fall)Ns=(1/e2)*(Mfall-∑Nd*e)–forceneededtoresistM(fall)e2= l - 0,5m -a–distance from themiddleof compressionarea to themiddleofthetensileareaY7)Wall№3YcaseB


M(stab)<M(falling)Nd(wall6,575m) 189,36 kNe2 4,50 mNs 552,03 kNfyd 435,00 N/mm2As 1269,03 mm2

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Y8)Wall№4YcaseA


M(stab)>M(falling)Y9)Wall№4YcaseB


M(stab)>M(falling)Nd(wall6,575) 118,35 kNe2 5,54 mNs 98,41 kNfyd 435,00 N/mm2As 226,23 mm2

Y10)Wall№5Y


M(stab)>M(falling)

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Y11)Wall№6YcaseA


M(stab)<M(falling)Nd(wall8,35m) 180,36 kNe2 6,20 mNs 336,07 kNfyd 435,00 N/mm2As 772,57 mm2

Y12)Wall№6YcaseB


M(stab<M(falling)Nd(wall8,35m) 180,36 kNe2 6,18 mNs 320,09 kNfyd 435,00 N/mm2As 735,84 mm2

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Y13)Wall№7Y


M(stab)>M(falling)Y14)Wall№8Y


M(stab)>M(falling)

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5.9 CalculationofwallstiffnessinthedirectionX

A construction going from 3-25 floors and roof was taken intoconsideration.ThebasicwallstiffnesscalculationprocessinthedirectionXwillbediscussedbelow.

Figure19.LoadbearingwallsagainstwindloadinthedirectionXa) Wall№9X

n 1,00 L 80,00 mh 10,03 mb 0,25 mE 30000,00 MN/mm2I 21,02 m4A 2,51 m2ky 1,20 ν 0,30 k9x 3,65 MN/m∑k9x 3,65 MN/m

b) Wall№10X


35

c)Wall№11X


d)Wall№12X


e)Wall№13X


36

f)Wall№14X


g)Wall№15X


5.10 Calculationoftheforces,whichactingonthewallsinthedirectionX

Thebasichorizontal forceactingoneachwallcalculationprocess inthedirectionXwillbediscussedbelow.

∑kix 21,06470429 MN/mFy=Hd(roofsideB) 0,1025 MNνx 0,00486596 m

Q9x 0,01776275 MNQ10x 0,00443431 MNQ11x 0,00427882 MNQ12x 0,00074666 MNQ13x 0,01010422 MNQ14x 0,05209551 MNQ15x 0,01307772 MN

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5.11 CalculationandcomparisonofM(fall)andM(stab)inthedirectionX

The basic calculation and comparison process ofM(fall) andM(stab) intheXdirectionwillbediscussedbelow.

X1)Wall№9X

H1d=Q9x 17,76 kNM(falling) 19414,69 kNmNd(wall10,03m) 180,54 kNNda(roof) 317,47 kNNd(floor3-25directionX) 298,79 kN∑Nd 10862,81 kNfcd 17000,00 kNa 1,28 me 3,74 mM(stab) 40594,56 kNm

M(stab)>M(falling)X2)Wall№10X




M(stab)>M(falling)

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X4)Wall№12X


M(stab)>M(falling)

X5)Wall№13X




M(stab)>M(falling)

39

X7)Wall№15X


M(stab)>M(falling)

40

6 CONCLUSION

The aimof the thesiswas tomake basic stability calculations for a 25-storyhigh-risebuildingforPöyryOytobeabletocomparetheresultsofthisthesiswiththeirownofficecalculations.All of the calculation materials were taken from Eurocodes, thesupervisor’sprojectmaterialsandthecompany’smaterials.Thestabilitycalculationsweredonebyhandwith thehelpof theExcel tables.Also,specialconstructionprogramsforthecalculationofthemainloadswerenotused for this thesis. Formulasandcoefficientswere taken fromtheFinnishEurocodeand calculationswere constantlymonitoredbyHAMKsupervisor (Tapio Korkeamäki) and Pöyry Oy supervisors (AleksiPöyhönen,VilleVirnes).The calculationprocesswasdone four times.As theprojectwas in thedesigning phase there were a lot of structural changes. Different wallsizes and the location of loadbearing walls required different stabilitycalculationseachtime.Thecalculationsweremademanually.Somethingwas simplified. Nowadays designing programs can calculate almosteverythingexactly,andthentheresultscanbecomparedwiththisthesis.Thatiswhythecompanyalsohastheirowncalculations,whicharemoreprecise.Allof thecalculationsweredone for thewalls inXandYdirections.Asthe structural calculations are complicated for that type of building, allthe loadbearingandnonloadbearingwallsweretakenwithoutdoorandwindowopenings to simplify the calculationprocess. Tobeon the safeside, the biggest horizontal load for each building side was taken intoconsideration. The wind load for the roof level was taken for thecalculationforthewholestructure.Also,theverticalloadwasminimizedand takenwithout the live load. Thus, it was done to define themostcomplicatedwallcases.Allinall,whenallofthecalculationsweredone,itwasdetectedthatthemostdifficultcasesforthestabilityofthebuildingwerewallswithasmallacting normal force. Thus, thosewalls need tensile rebars to resist thefallingmoment,whichiscausedbyhorizontalforces.

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REFERENCES

Design and construction of high-rise buildings, Retrieved 17.01.2017 from https://www.abok.ru/for_spec/articles.php?nid=2444 High-rise building construction, Retrieved 17.01.2017 from http://www.sbrm.ru/stroitelnye-raboty/monolit/vysotnoe-domostroenie/ Pöyry Oy, Retrieved from 20.01.2017 http://www.poyry.com Rist,V.C.& Swensson S. (2016) Methodology for preliminary design of high-rise buildings. Master’s Dissertation. Lund University SFS-EN 1991-1-1:2002 SFS-EN 1991-1-3:2003 SFS-EN 1991-1-4:2005

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STRUCTURAL DESIGN BASIS FOR HIGH-RISE RESIDENTIAL BUILDINGS