Upload
aquibzafar
View
233
Download
0
Embed Size (px)
Citation preview
8/12/2019 Follett Tech 3
1/47
8/12/2019 Follett Tech 3
2/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page2
TableofContents:TableofContents...2ExecutiveSummary.....3Introduction...4ExistingCompositeJoistandPrecastConcretePlankSystem...5ApplicableCodes,DesignCriteriaandLoadCases......8BuildingDesignLoadsandLateralCriteria.........9LoadDistributionandAnalysis.....12
DeterminationofRelativeStiffness(k)andCenterofRigidity....12DeterminationofDirectandTorsionalShear.... 12,13
FrameAnalysis.. 15PortalFrameAnalysis........15STAAD.Pro2006Analysis......15MemberVerificationandStrengthChecks.17
ServiceabilityCheck(DriftAnalysis)... 26OverturningMomentandUplift... 27Conclusion.......29AppendixA:BuildingLayout...30AppendixB:WindandSeismicDesignData........33AppendixC:CenterofMassandRigidity..36AppendixD:PortalFrameAnalysisCalculations....38AppendixE:TorsionalForceTables.....44
8/12/2019 Follett Tech 3
3/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page3
ExecutiveSummary:WashingtonParkCondominiumsisan8storymultiuseretailandresidentialbuildinglocatedin
Mt.Lebanon,Pennsylvania. Thelateralforceresistingsystemofthebuildingwhichwillbe
studiedinthisreportisasteelmomentframesystem. Therearefourframesthatruninthe
northsouthdirectionofthebuildingwhichalsoisthelongestlengthofthebuilding.Furthermore,therearenine,3baymomentframesthatrunintheeastwestdirectionofthe
building. Theseframesareconnectedtobraceframesinthebasementandsubbasement
levelswhichhelptocarrythesoilpressureandtransferthelateralloadtothefoundations.
ThepurposeofTechnicalReport#3wastoinvestigatethelateralsystemofthebuildingandto
prepareananalysisanddesignverificationsummaryofthestructure. Theloadsfoundin
TechnicalReport#1wereusedasabaseandwereeventuallymodifiedbasedonthestiffnesss
oftheframesthatwasdeterminedduringthedesignandanalysisprocess. Theinvestigation
usedhandmethodsalongwithcomputeranalysistodetermineanddiscussthefollowing:
DirectandTorsionalShearForces
ControllingLoadCombinations
LogicalLoadPath
StoryandOverallStructureDrift
Beam,ColumnandBraceStrength
OverturningMomentsandUplift
Theanalysisshowshowthemomentframes,runninginbothdirectionsthroughthebuilding,
resistthelateralforcesthatareappliedbybothwindandseismic. Oncetheloadswereapplied
tothestructureaframeanalysiswasperformedbybothhandcalculationandcomputer
modeling. Thisallowedthestrengthofcertaincriticalmemberstobeaccessed. After
reviewingthesemembersitwasdeterminedthatthemembersizeswerechosenbasedonthe
governingdrift. Uponcompletionoftheanalysisitwasdeterminedthatinmostcasesthewind
controlsthelateraldesign. However,thisisnotapparentinthedriftcalculationswhichshow
thewinddriftsmeetingtheacceptablecodelimitswhiletheseismicdriftsfailsthelimits
deemedacceptablebycode. Thisissuewillbestudiedatlengthintheproposaltoseeifthere
isreallyanissueintermsofseismicdriftandifsohowcanthedriftbeminimizedwithout
compromisingthearchitecturalaspectsofthefloorsystemandthereforevastlyincreasing
buildingcosts.
8/12/2019 Follett Tech 3
4/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page4
Introduction:
WashingtonParkCondominiumsisamultiuseretailandresidentialbuildinglocatedatthe
intersectionofBowerHillRoadandWashingtonRoadinMt.Lebanon,Pennsylvania. Sitework
andexcavationhasbegunatthesiteandconstructionshouldbeginsometimebeforetheend
ofthefall2008,withtheprojectlastinguntilfall2010. WashingtonParkCondominiumsisthe
firstoftwobuildingsproposedtobebuiltonthesite. Buildingoneisaninestory,148,000ft2
structurewhichisownedbyZamagiasPropertiesofPittsburgh,PA. Thebuildingwas
architecturallydesignedbyIndovinaAssociatesArchitectsandisbeingconstructedbyPJDick,
Inc.forapriceof$23,418,000. Thebuildingsprimaryuseisresidentialanditcontains7stories
ofcondominiumsonthe2ndthrough8
thfloors. Thefirstfloorofthebuildingisusedforretail
spaceandasalocationforextraamenitiesfortheresidentsofWashingtonPark. Thebuilding
alsocontainstwobelowgradelevelsofparking. Theenclosedparkinggaragecontains78
parkingspacesthatcanbeusedbytheresidents. Twoelevatorsandtwostairsservethe
parkingareasthatalsocontainresidentstorage,awineroomandtrashcollectionalongwith
mechanicalandelectricalrooms. Thegroundfloorservesprimarilyasretailspacewithfour
separateareasavailableforpossibletenants. Alsocontainedonthefloorarearesident
exerciseroomandaprivateentranceandlobbyfortheresidents.
Asthebuildingmovestothesecondfloor,thefunctionchangesfromprimarilyretailtooneof
solelyresidentialwithsixupscalecondominiumslocatedonthefloor. Thesecondominiums
eachhavedifferentfloorplansandlayoutswithoverallareasrangingfrom1523ft2to2288ft
2.
Eachunitcontainstwoorthreebedroomsandbathroomsdependingonsize,alongwithaliving
room,diningroom,kitchen,study,laundry,entryandinsomecasesabalcony. Thisfloorlayoutcontinuesthroughoutthenextfourfloors,withatotalof30unitsonfloors2through6. The7
th
and8thfloorsofthebuildingarethepenthouselevel. Thisfloorcontainsfivecondominiums
thatrangefrom1732ft2to2453ft
2. Theseunitscontainthesameamenitiesandspacesasthe
unitsonthebelowfloorsdo. Allofthecondominiumsfloorsareservedbytwoelevatorsand
twostairwaysthatareconnectedbyahallwaythatrunsthroughthecenterofthebuildingin
thelongdirection. Finally,theroofcontainsmechanicalspacesthatareaccessedbyusingthe
northernmoststairwayorelevator.
Thetypicalexteriorwallsystemofthebuildingconsistsmainlyof4brickveneerbackedbya2
airspaceand2ofrigidXPSinsulation,thencontaininganother2layerofrigidsprayfoam
insulationthatisfollowedbyanairspaceandthen5/8gypsumboard. Thisexteriorwall
systemistypicalforthefirst6floorsofthebuilding. The7thand8
thfloorsofthebuilding
consistofasimilarwallconstructionexceptfortheexteriorfaadewhichisa5/16layerof
paintedfibercementsiding.
8/12/2019 Follett Tech 3
5/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page5
ExistingCompositeJoistandPrecastConcretePlankSystem:FoundationsThefoundationsystemcanbebestdescribedasaspreadfootingsystemwithattached
concretepiers. Thesizesforthespreadfootingsrangefromthesmallest,a40x40x20footingwith#8@12eachway,toa140x140x36footingwith#8@6eachwaywith
thedeepestofthefootingswillbe250belowgrade. Inadditiontothespreadfootings,
interiorandexteriorwallfootingswereusedandareeither20or30wideby14deep.
Thesteelreinforcinginthesewallfootingsare(3)#5continuousbarsand#5x18@16.
Theslabongradeinthissystemconsistofeithera6or8normalweightconcreteslab
reinforcedwith6x6W2.9xW2.9weldedwirefabricor6x6W4xW4weldedwirefabric.Theslab
ongradeisalsothickenedtoaminimumif10atnonloadbearingwallsand(2)#4barsare
addedfortensilestrength. Connectingthecolumnstotheslabongradeandthefootingsare
columnpiersthatrangefrom16x16with(4)#7ofverticalreinforcementto40x40w/
(12)#7ofverticalreinforcementandfc=4000psiconcreteisusedfortheentiresystem.FloorSystemsTwoseparatefloorssystemsaretypicalwithinthestructureofWashingtonPark. Thefirstisa
precastconcreteplanksystemthatisusedintheparkingareasaswellasthefirstandsecond
floorframing. Theprecastconcreteplankis8thickandalsocontainsa2thickstructural
topping. Thereinforcinginthestructuraltoppingis6x6W1.4xW1.4weldedwirefabric. The
precastconcreteplanksystembearsonWshapeswhichthencarrytheloadtothecolumns.
Thissystemwasusedintheparkingareasbecauseofthesystemsdiaphragmcapacity(abilityto
transferhorizontalloading)andbecauseofitsdurabilityandstrength.
ThesecondprimaryfloorsysteminthebuildingistheVESCOMcompositejoistfloorsystem.
Thecompositejoistsysteminterlocksthetopchordofajoistwiththeconcreteproducingless
deflection,lessvibrationandgreaterstiffness. Thefloorconstructionconsistsofa211/16
reducedweightconcreteslabthatispouredontopofthe15/16,22Gagegalvanizedfloor
decking. Thebottomchordactsasthemaintensionmember,andinthecompositestagethe
embeddedtopchordservesasacontinuousshearconnection. Theconcreteisalsoreinforced
withweldedwirefabricandcompressivestrengthoftheconcreteisfc=3500psi. Finally,the
systemwasusedasanarchitecturalelementsincetheceilingcouldbeinstalleddirectlytothe
joistbottomchordandthemechanicalsystems(HVAC,plumbing,fireprotection,electricaland
telecommunications)couldbeinstalledwiththejoistsystem,savingspaceandallowingfor
higherceilingsandfloortofloorheightwithintheapartments. AsectionoftheVESCOM
CompositefloorsystemcanbefoundinAppendixB.
8/12/2019 Follett Tech 3
6/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page6
LateralSystemThelateralresistingsystemwithinthebuildingismainlymomentresistingsteelframesmade
upofwideflangebeams. Theseframesbeginonthesecondfloorandcontinueupthroughthe
topofthebuilding.TheseframesruninthenorthsouthdirectionandrunalongcolumnlinesA,
B,CandD. Rigidconnectionsalsooccuronthesefloorsalongcolumnlines1through9. Figure
1belowshowsthefourdifferenttypesofmomentframesthatexistwithinthebuilding. These
fourframesSincetheVESCOMfloorsystemisbeingusedasadiaphragmtotransfershear
loadingtheloadpathbeginsattheexteriorbeamsandthencontinueonthroughthefloor
systemtojoistgirderswhicharetobedesignedandmanufacturedbythejoistmanufacturer.
TheloadisthentransferredintothelargeW14columns,andfinallytothebraceframesandthe
foundations. Thereareatotalofelevenbracedframeslocatedinthebasementandsub
basementlevelsrunningalongcolumnlines1through11fromcolumnlinesA.1toB. Thebrace
framesare172inlengthandtheybeginatthesubbasementlevelandconnectintothe
framingforthegroundfloor. ThebracingintheframesconsistsofHSS8x8x1/2uptothe
basementlevel,andHSS6x6x3/8fromthebasementleveltothegroundfloor. Theseframes
areshowninFigure2below. Thisplandetailandthedetailofthebraceframescanbefoundin
Figures2and3.
Figure1:BracedFrameLocation
NorthSouthFrames(A&D)
NorthSouthFrames(B&C)
EastWestFrames(FthruL)
EastWestFrames(E&M)
(0,0)
Figure1:MomentFrameDiagram
8/12/2019 Follett Tech 3
7/47
8/12/2019 Follett Tech 3
8/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page8
ApplicableCodes,DesignCriteriaandLoadCasesSinceanindepthlateralanalysiswasperformedthereweremanyreferencemanualsand
materialsthatwereusedtocompletethedesign,thesearelistedasfollows:
IBC2003withAmendmentsforMt.Lebanon,Pennsylvania ASCE705:MinimumDesignLoadsforBuildingsandOtherStructures
ACI31808BuildingCodeandCommentary
DesignofConcreteStructuresTextbook(AE431)
AISCSpecificationforStructuralSteelBuildings,13thEdition
RAMStructuralSystem(GravityLoads)
STAADPro2006(LateralLoadAnalysis)
DesignDeflectionCriterionThefollowingdesigncriterionwasalsousedandcanbefoundinIBC2006andASCE705:
=H/400forAllowableStoryandBuildingDriftduetoWindLoading
=0.015hsxforAllowableStoryandBuildingDriftduetoSeismicLoading
DesignLoadCombinationsThefollowingLoadandResistanceFactorDesignloadcombinationswereconsideredfor
analysis,asnotedinASCE705Chapter2:
1.4(Dead)
1.2(Dead)+1.6(Live)+0.5(RoofLive)
1.2(Dead)+1.6(RoofLive)+0.8(Wind)
1.2(Dead)+1.6(Snow)+0.8(Wind)
1.2(Dead)+1.6(Snow)+1.0(Live)
1.2(Dead)+1.6(Wind)+1.0(Live)+0.5(Snow)
1.2(Dead)+1.6(Wind)+1.0(Live)+0.5(RoofLive)
1.2(Dead)+1.0(Earthquake)+1.0(Live)+0.2(Snow)
8/12/2019 Follett Tech 3
9/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page9
BuildingDesignLoadsandLateralCriteriaInordertocompleteananalysisofWashingtonParkCondominiums,thatgravityandlateral
loadsactingonthebuildingneedtobeidentified. Thedeadandliveloadsthatareusedwere
alsousedinTechnicalReport#1becauseitwasdeterminedthatthoseloadscloselymatched
thoseusedbythedesignengineer. Thelateralloadswererecalculatedbydeterminingthe
equivalentstiffnessforeachmomentframeinthebuilding. Findingthestiffnessofeachframe
allowedforthedirectshearandtorsionalshearateachleveltobecalculatedandfortheloads
tobedistributedthroughoutthebuildingaccordingtostiffness. Theseloadsandtheprocessin
whichtheyweredeterminedwillbediscussedindetailinthenextsection. Thetablesbelow
listthedeadandliveloadsforthebuildingaswellasthewindandseismicdesigncriteriaused
inthecomputationofthelateralloads.
GravityLoads
Table1:DeadLoadTables
DeadLoadTableFloorDeadLoad RoofDeadLoad
Material/System Load Material/System Load
NormalWeightConcrete 145pcf
411/16"RWCSlab
on15/16"FLR
Deck
68psf
Steel PerShape MEP 6psf
BrickVeneerw/studs 40psf Sprinklers 3psf
8"P/CPlankw/2"StructuralTopping 90psfCeiling 8psf
VESCOMJoists
4psf
MEP 6psfAsphalt
Shingles/Felts4psf
Sprinklers 3psf
1/2"Cement
BondedParticle
Board
5psf
Ceiling 5psf
LightGaugeRoof
Trusses@2'0"
O.C.
4psf
FloorFinishes 5psf
Partitions 20psf
VESCOMJoists 4psf211/16"RWCSlabon15/16"FLR
Deck43psf
8/12/2019 Follett Tech 3
10/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page10
LiveLoadTableFloorLiveLoadTable RoofLiveandSnowLoadTable
Occupancy
Load
Material/System
Load
Typ.CondominiumFloor 40psf RoofLiveLoad 20psf
Stairs 100psfRoofLiveLoad
(Mechanical)150psf
FirstLevel(PlazaandTraffic/Parking
Areas250psf
GroundSnowLoad
(Pg)25psf
FirstLevel(NonPlazaAreas) 100psfFlatRoofSnow
Load(Pf)23psf
BasementLevelParkingAreas/Ramps 50psfExposureFactor
(Ce)1.2
SlabsonGrade 150psf ThermalFactor(Ct) 1
ExerciseAreaatGroundFloor 150psfImportanceFactor
(I)1.1
CorridorsOn1stFloor 100psf
CorridorsAbove1stFloor 80psf
Mech/ElecSpaces 150psf
SecondFloorTerrace 100psf
ApartmentBalconies 100psf
Table2:LiveLoadTablesWindCriteriaThewindloadsforWashingtonParkCondominiumswerecalculatedusingthedesigncriteria
foundinASCE705,Chapter6anditwasdeterminedthatitwaspermittedtouseMethod2
AnalyticalProcedureforthedesign. Thetablebelowliststheapplicablewinddesignfactors.
Basic Wind Speed (V) 90 mph
Wind Direction Factor (Kd) 0.85
Importance Factor (I) 1
Exposure Category C
Velocity Pressure Coefficient (Kz) Case 2
Topographic Factor (Kzt) 1
Enclosure Class Enclosed
Table3:WindDesignCriteria
8/12/2019 Follett Tech 3
11/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page11
SeismicCriteriaTheseismicloadsforWashingtonParkCondominiumswerecalculatedusingASCE705,
Chapter12,aswellasusingtheinformationprovidedbythestructuralengineerandthe
geotechnicalengineer. Fromthegeotechnicalreport,itwasdeterminedthattheSiteClassfor
constructionwouldbeSiteClassC. Theremainderoftheinformationneededtocalculate
seismicloadingandbaseshearwasfoundinChapter12ofASCE705. Thetablebelowliststhe
applicableseismicdesignfactors.
SeismicParametersforWashingtonParkCondominiums
Ss S1 SiteClass Fa Fv Sds Sd1SeismicDesign
Category
SeismicUse
Group
0.128 0.058 C 1.6 2.4 0.137 0.093 B I
I R Cu Ta TL Ts Cs k PeriodCoefficient
1 3.5 1.7 1.082 12 0.6333 0.01706 1.291 0.80
Table4:SeismicDesignParameters
8/12/2019 Follett Tech 3
12/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page12
LoadDistributionandAnalysisThedistributionoflateralforcesthroughoutthestructurecanbedeterminedusingvarying
designmethods. Forthistechnicalreportthelateralloadswereascertainedbasedonthe
relativestiffnessofeachframeinconjunctionwiththerestoftheframesinthebuilding. The
compositejoistfloorsystemisusedasasheardiaphragmanditdistributesloadtothevarious
framesbasedontheirrespectiverelativestiffness. Thisprocessallowsforamoreaccurate
distributionofloadsalongwiththeabilitytostudyhowtheframesworktogethertotransfer
theloadsfromthemomentframestothefoundations. Fortheanalysis,handcalculations,
MicrosoftExcelandSTAAD.Pro2006wereutilizedasawaytoobtainamorethorough
understandingofthedistribution.
DeterminationofRelativeStiffness(k)andCenterofRigidityThedeterminationofeachframesrelativestiffnesswasdoneusinghandcalculationsand
STAAD.Pro2006. Tobeginthefourdifferentframes(interiorandexteriorineachdirection)
wereconstructedinSTAADusingthesteelsizesandconnectionsgivenbythestructural
engineer. Nextaonekiploadwasappliedatthetopofeachmomentframetoestablishthe
amountofdeflectionthatoccursatthetopoftheframe. Fromthere,theinverseofthis
deflectionwastakenandthesevalueswereusedfork. Fromthesekvalues,thecenterof
rigidityofthebuildingwasfound. Thexandydistancevaluesusedforthecenterofrigidity
weretakenfroma(0,0)pointchosenonthebottomrightcornerofthebuildingasshownin
AppendixC. Therelativestiffnesssforeachframeareincludedinthetableforthedirectand
torsionalshearshownbelow.
DeterminationofDirectShearandTorsionalShearAfterestablishingthestiffnessvaluesforeachframe,thedirectandtorsionalshearsforeach
frameateachlevelcouldbedetermined. Forthisanalysis,itwasdecidedthatfourregular
framescouldbechosenthatwouldberepresentativeofalltheframesinthebuilding. Frames
AandEaretheexteriorframesinthenorth southandeast westdirectionsrespectively.
Also,framesCandFaretheinteriorframesinthenorth southandeast westdirections
respectively. Thecalculationforthemomentsforeachframeateachfloorusedinthetorsional
forcecanbefoundinAppendixF. Thedirectandtorsionalshearsarethenfoundbyusingthe
followingequationsandvariables. ThesevariablescanbefoundinTable5belowalongwith
thevaluesfortheforcesofthefourframesthatarebeingstudied:
8/12/2019 Follett Tech 3
13/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page13
Where: K=EquivalentStiffnessofFrame
Fi=LateralStoryForce
Mi=Fix(dCMdR)
di=DistancefromCenterofRigiditytoFrame
TorsionConstants
FloorCenterofRigidity CenterofMass
IX (in4) Iy (in
4) IP (in4)
XR(ft) YR(ft) XR(ft) YR(ft)
Second 104.92 39.89 102.3 34.7 2837888.75 353494.66 3191383.41
Third 104.92 39.89 102.3 34.7 2837888.75 353494.66 3191383.41
Fourth 104.92 39.89 102.3 34.7 2837888.75 353494.66 3191383.41
Fifth
104.92
39.89
102.3
34.7
2837888.75
353494.66
3191383.41
Sixth 104.92 39.89 102.3 34.7 2837888.75 353494.66 3191383.41
Seventh 104.92 39.89 102.3 34.7 2837888.75 353494.66 3191383.41
Eighth 104.92 39.89 102.3 34.7 2837888.75 353494.66 3191383.41
Roof 104.92 39.89 102.3 34.7 2837888.75 353494.66 3191383.41
Table5:CenterofRigidityandMassalongwithCalculatedMomentofInertia
Table6:ResultantShearsDuetoWindLoading
8/12/2019 Follett Tech 3
14/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page14
Table7:ResultantShearsDuetoSeismicLoadingAfterobtainingthedirectandtorsionalforcesforeachframeitisobviousthatthesevaluesare
smallerthanthatofstoryforcesthataredeterminedusingtributaryarea. Thiscouldbedueto
thefactthatusingrelativestiffnessallowsforthebuildingtobeanalyzedasanentirestructure
sincethedirectshearsaredeterminedbyusingaratioofframestiffnesstototalstiffness. The
methodoftributaryareadoesnottakeintoaccountanyotherframeorhowtheotherframes
inthebuildingmaybeworkingtogethertodistributethelateralloadthroughoutthebuilding.
Thisallowsforthecalculatedforcesusingtherelativestiffnesstobemoreaccurateand
thereforemakethesubsequentportalframe,strengthanddriftanalysesmorereliable.
8/12/2019 Follett Tech 3
15/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page15
FrameAnalysisPortalFrameFollowingthedeterminationofthedirectandtorsionalforcesthroughtheestablishmentof
relativestiffness,thestoryforceswereappliedtothestructureandwereanalyzedusingPortalMethod. Inthiscase,threedifferentportalmethodanalyseswereperformed. FramesEandF
wereanalyzedusingresultantshearsduetowindsincethevaluefortotalshearduetowind
weregreaterthanthatofseismic. Next,asinglefloorofframeCwasanalyzedusingthe
resultantshearduetoseismicloadingsinceforframeCtheshearforseismicwasgreaterthan
theshearduetowind. Themomentsinthebeamsandcolumnsthatwereobtainedfromthe
portalframeanalysiswereusedinthebeamandcolumnstrengthchecks. Theresultsofthe
portalframeanalysiscanbefoundinAppendixD.
STAADAnalysisInconjunctionwiththeportalframeanalysis,aframeanalysisusingSTAAD.Pro2006was
performed. Thisanalysiswasusefulinprovidinginformationconcerningstoryandoverall
buildingdriftaswellasdeterminingwhetherornotthesteelmemberschoseninthedesign
wereadequatetocarrytheloads. Figures4and5belowshowthetwoframeconstructions
thatwereanalyzedusingSTAAD. Foreaseofanalysisalongwithaconservativedesign,frames
AandCwereanalyzedasiftheywerestraightmomentframes. Thiswasdonebecausethe
entireframeworkstogetherandacontinuousframewouldbemoreconservativeintermsof
windloadsaddedtothebuilding. Furthermore,bothtypesofframeswereanalyzedtwicefor
exteriorandinteriormomentframeconditions. Ineachcase,thelateralforcesthatwereaddedtotheframewerechangedbasedonthevaluesthatweredeterminedfortotalstory
shearinTables2and3onthepreviouspages. Usingtheseloadsthatstorydriftsandoverall
driftofthebuildingwasdeterminedandwasusedinthecomparisonwiththeallowabledrift
valuesdeterminedinTables4and5. STAADwasalsousedtodeterminethecontrollingload
combinationsineachdirection. Thefollowingloadcombinationscontrolinthegivendirection.
Finally,theSTAADmodelwasoneofthewaysthatsteelmembersusedinthebuildingsdesign
wereverified. Thesesteelshapeswerealsodesignedinthememberandstrengthchecks
beginningonthenextpage. Overall,usingSTAADallowedforasimplifiedmethodofmember
verificationanddriftanalysis,aswellasamethodofcomparisontothehandcalculationsperformedforbothmemberandframechecks.
8/12/2019 Follett Tech 3
16/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page16
Bythecomputeranalysisitwasdeterminedthatthecontrollingloadcombinationsforeach
directionwereasfollows:
NorthSouthDirection(FramesAthruD):1.2(Dead)+1.0(Earthquake)+1.0(Live)+0.2(Snow)
EastWestDirection(FramesEthruM):1.2(Dead)+1.6(Wind)+1.0(Live)+0.5(Snow)
Thesecombinationsmakessensesincetheshorterofthemomentsframeswouldbecontrolled
bythewindloadssincethestoryshearsontheframewouldbearesultofthewindpressures
onthelongsideofthebuilding. Theseloadcombinationswereusedtoverifymembersizes
andstrengthsinthenextsection.
Figure4:FramesEandF(EastWestDirection)
Figure5:FramesAandC(NorthSouthDirection)
8/12/2019 Follett Tech 3
17/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page17
MemberVerificationandStrengthChecksUponcompletionoftheportalmethod,themomentsfromtheanalysiswereusedin
conjunctionwithmomentsandforcesfoundintheSTAADanalysistoverifybeam,columnand
braceframemembersthroughoutthebuilding. Membersinframesrunningbothnorthsouth
andeastwestwereanalyzedusingthecontrollingloadcombinationandaredenotedonthe
calculations. AlthoughthemembersweredesignedandcheckedusingSTAAD,itisstill
necessarytocheckthecomputeroutputsothatacompetentunderstandingofmember
strengthcanbeachieved. ThemembersthatwerechosenareshowninFigure6. Boththeblue
andredhighlightedmembersarethelongestspanningbeamsintheirrespectivemoment
framesandthereforewerechosenforanalysis. Thecolumns,denotedbycircles,werechosen
basedbecauseintheportalanalysistheinteriorcolumnscarrytwicetheshearwhenthelateral
loadsaredistributedthroughouttheframe. Finally,abraceineachofthebracedframeswas
designedfortheaxialloadcausedbydead,wind,liveandsoilpressure.
Figure6:MembersusedforVerification(FramesCandF)W18x97(FrameF)
W18x97(FrameC)
W14x90(FrameF)
W14x90(FrameC)
8/12/2019 Follett Tech 3
18/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page18
FrameF:BeamandColumnStrengthChecks(RedonPlan)
8/12/2019 Follett Tech 3
19/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page19
8/12/2019 Follett Tech 3
20/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page20
8/12/2019 Follett Tech 3
21/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page21
FrameC:BeamandColumnStrengthChecks(BlueonPlan)
8/12/2019 Follett Tech 3
22/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page22
8/12/2019 Follett Tech 3
23/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page23
8/12/2019 Follett Tech 3
24/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page24
BracedFrameStrengthChecks
8/12/2019 Follett Tech 3
25/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page25
8/12/2019 Follett Tech 3
26/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page26
ServiceabilityCheck(DriftAnalysis)Thedriftofastructureisextremelyimportanttotheoverallperformanceofthebuilding. Too
muchstorydriftortotaldriftinastructurecouldresultindamagetothebuildingexteriorand
othersystemscausingrepairsandobviouslyaddedcostsduetomaintenance. Becauseofthis
theIBCandASCE705havelaidoutparametersfordriftcontrolbasedonoccupancycategory,
buildingheightandstructuretype. InthecaseofWashingtonParkCondominiumsthewind
driftdeterminedinSTAADwascomparedtow=H/400fortheentirebuilding. Theseismic
drift,alsodeterminedinSTAAD,wascomparedtoS=0.015hsxwherehsxisthestoryheightof
thebuildingatacertainlevel. TheallowablewinddriftcanbefoundonTable1604.3oftheIBC
andtheallowabledriftduetoseismicisfoundonTable12.121inASCE705. Thetablesbelow
displaythecomparisonbetweenactualandallowabledriftforbothwindandseismic.
Table8:ActualWindDriftComparedtoAllowableDriftControllingSeismicDrift
Floor
Story
Height
(ft)
Total
Height
(ft)
Story
Drift
(in)
AllowableStory
Drift(in)
seismic=0.020hsx
Acceptable?
Total
Drift
(in)
AllowableStory
Drift(in)
seismic=0.020hsx
Acceptable?
Second 14.333 14.33 0.232
8/12/2019 Follett Tech 3
27/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page27
Asdisplayedintheabovetablesthecontrollingwinddriftinthebuildingisacceptableatboth
individualfloorsandfortheoverallheightofthebuildingwhencomparedtothecode
allowabledriftofw=H/400. However,thecontrollingseismicdriftinthebuildingisgreater
thanthecodeallowablevalueofS=0.020hsx. Apossiblereasonforthiscouldbethefactthat
theindividualmomentframeswereanalyzedindividuallyinSTAAD. Anotherreasoncouldbe
thefactthatwithintheanalysisthatbracedframeslocatedonthebasementandsubbasement
levelswerenotincludedinthecalculationsincetheyareconsideredtobebelowgrade. These
bracedframesprimarilyservetoresistthesoilpressurewhichcanbeseeninthebracedframe
strengthchecks. Anotherpossibilityisthefactthatthestiffnessofthecompositejoistfloor
systemwasnottakenintoaccount. Since,thefloorsystemservesasadiaphragm,itcanalso
beassumedthatitalsohassomelevelofstiffnessandthereforewouldhelptoresistand
transfersomeamountoflateralloadingtothecolumnsandultimatelythefoundations. Many
solutionstotheproblemcouldbeusedincluding,increasecolumnandbeamsizesandpossibly
addedsomebracedframesthroughoutthebuilding. Regardlessofthesolutionthatisused,the
issueofmorethanallowablestoryandoveralldriftinthestructurecouldbestudiedinmore
depthintheproposalandresearchlater.
OverturningMomentandUpliftOneoftheissuesthatarerarelyconsideredwhencompletinglateralanalysisonastructureis
howthelateralloadsandensuingtransferofthoselateralloadstothefoundationswillimpact
theirsize. Theimpactofthefoundationsthatneedstobeconsiderediscausedbywindand
seismicforcesproducinganoverturningmomentforthebuilding. Inturn,theoverturning
moment,
may
cause
uplift
within
the
exterior
columns
and
foundations
of
the
building
because
thereisnotenoughdeadweightonthecolumnsandfoundationstoresisttheoverturning
moment. Tables6and7listtheupliftfoundduetowindandseismicloadinginbothdirections.
UpliftDuetoWindLoading
Moment
(kft)
UpliftForce
(kips)
DeadLoad
Resistance(kips)UpliftProblem?
East West
Direction24400.21 389.36 271.24 Yes
North SouthDirection
6606.64 32.67 463.79 No
Table10:UpliftduetoWindLoading
8/12/2019 Follett Tech 3
28/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page28
UpliftDuetoSeismicLoading
Moment
(kft)
UpliftForce
(kips)
DeadLoad
Resistance(kips)UpliftProblem?
East West
Direction15850.95 252.94 271.24 No
North South
Direction15850.95 78.38 463.79 No
Table11:UpliftduetoSeismicLoadingTheresultsoftheupliftcalculationshowthattherewouldbenetupliftforcesintheeastwest
directionduetowindloads. Becauseofthisthefoundationswouldneedtobedesignedto
resistanetupliftof118.12kips. Currentlythefoundationsontheexteriorofthebuildingrange
from8.5
x8.5
to
13
x13
and
are
placed
25
below
grade.
This
gives
the
foundations
the
abilitytoresistthenetupliftforcesappliedbytheoverturningmoment. Asaresultofthe2
storybasementandnetupliftthefloorsystembelowgradeaswellastheslabongradeisused
tohelptiethevariousfoundationstogether. Thisalsohelpedresistslidingandoverturning
forcescausedbytheimbalanceofsoilpressureaswellastheuplift. Finally,someofthe
foundationswereinserteddirectlyintotherockandutilizedrockskinfrictiontoresistupliftas
wellasincreasingtheslidingresistanceofthefoundationsystem. Overall,itseemsthatthe
presentfoundationsareadequateinresistingthenetuplift.
8/12/2019 Follett Tech 3
29/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page29
ConclusionThelateralanalysisanddesignofthemomentframestructureforWashingtonPark
Condominiumswasdiscussedindetailedthroughoutthistechnicalreport. Thereportexamines
theprocesswhichwastakentoarriveatdesignoflateralmemberswithintheframesthrough
bothhandcalculationsandcomputermodeling. Bothhandcalculationsandcomputer
modelingwereusedtodeterminetherelativestiffnessfactorsforeachframe. Fromthere,the
directandtorsionalshearforcesoneachlevelofeachframewerecalculatedsothattheycould
appliedtotheframeandcomparedtotheresultsfoundinTechnicalReport#1. After
determiningtheforcestobeappliedtotheseparateframes,itwasnecessarytocompletea
portalframeanalysisalongwithacomputeranalysis. Theportalframeanalysisrenderedshear
andmomentsinthebeamsandcolumnsoftheframes. Thecomputermodelanalyzedin
STAADallowedforacomparisonandcheckoftheportalframeanalysis. TheSTAADmodelwas
alsousedtodeterminethecontrollingloadcasesforeachframeanddeterminethedriftof
bothintheindividualstoriesandtheentireframe. Afterobtainingthevaluesfordriftfrom
STAADtheywerecomparedtotheallowabledriftlimitsforbothwindandseismicgiveninthe
InternationalBuildingCodeandASCE705. Thecontrollingwinddriftwasdeemedacceptable
bycode,howeverthestorydriftandoverallstructuredriftduetoseismicloadswerefoundto
beabovetheacceptablecodelimits. Althoughthevaluesdidnotmeettheacceptablelimits
foundinthecode,itisbelievedthatthereasonforthiscouldbecontributedtothefactthatthe
stiffnessofthecompositejoistfloorsystemwasnottakenintoaccount. Since,thefloorsystem
servesasadiaphragm,itcanalsobeassumedthatitalsohassomelevelofstiffnessand
thereforewouldhelptoresistandtransfersomeamountoflateralloadingtothecolumnsand
ultimatelythefoundations.
Alongwiththedriftcalculations,thedesignstrengthofseveralcriticalmembersofthedifferent
frameswereanalyzedbasedontheloadsandmomentsfoundintheSTAADanalysis. All
membersthatwerelookedatwerewellwithintheirultimatecapacitygivenbytheAISC
SpecificationforStructuralSteelBuildings,13thEdition. Finally,anoverturningmomentand
upliftcheckwasdonetoseeifthiswouldbeanissueforthefoundations. Itwasdetermined
thatintheeastwestdirectiontheremaybeanissuewithuplift. Thiswillbefurtherexamined
intheproposalandcouldleadtofurtherdiscussionofthefoundationsystemusedonthe
project.
Ultimately,itwasconcludedthatthelateralsystemissufficientlydesignedtocarrythelateral
loadingofthebuilding. Thedriftissueswillbediscussedandexaminedingreaterdetail
throughtheproposalandfollowingresearch.
8/12/2019 Follett Tech 3
30/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page30
AppendixA:BuildingLayout
8/12/2019 Follett Tech 3
31/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page31
TypicalFloorLayout
8/12/2019 Follett Tech 3
32/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page32
CompositeJoistSystemIsometricSection
8/12/2019 Follett Tech 3
33/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page33
AppendixB:WindandSeismicData
8/12/2019 Follett Tech 3
34/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page34
WindLoadingCoefficientsandStoryResultsFloor Kz Kzt Kd Kh V (mph) I qh (lb/ft
2) qz (lb/ft
2)
2nd 0.849 1.0 0.85 1.253 90.0 1.0 22.085 14.964
3rd 0.948 1.0 0.85 1.253 90.0 1.0 22.085 16.709
4th 1.023 1.0 0.85 1.253 90.0 1.0 22.085 18.031
5th 1.081 1.0 0.85 1.253 90.0 1.0 22.085 19.053
6th 1.13 1.0 0.85 1.253 90.0 1.0 22.085 19.917
7th 1.172 1.0 0.85 1.253 90.0 1.0 22.085 20.657
8th 1.216 1.0 0.85 1.253 90.0 1.0 22.085 21.433
Roof 1.256 1.0 0.85 1.253 90.0 1.0 22.085 22.138
qz=0.00256KzKztKdV2I(lb/ft
2) qh=0.00256KhKztKdV
2I(lb/ft
2)
Wind (North - South Direction)
Floor Height(ft)
TributaryHeight(ft)
Kz qz
(psf)Windward
(psf)Leeward
(psf)Total(psf)
StoryForce(kips)
StoryShear(kips)
OverturningMoment (ft-k)
Ground 0.00 0.00 0.849 0.00 0.00 0.00 0.00 0.00 128.694 6487.847
Second 14.33 13.667 0.849 14.964 10.403 -5.758 16.161 15.166 128.694 6487.847
Third 25.33 11.000 0.948 16.709 11.616 -5.758 17.374 13.123 113.528 4905.356
Fourth 36.33 11.000 1.023 18.031 12.535 -5.758 18.293 13.817 100.405 3728.723
Fifth 47.33 11.000 1.081 19.053 13.246 -5.758 19.003 14.354 86.588 2076.624
Sixth 58.33 11.000 1.130 19.917 13.846 -5.758 19.604 14.807 72.235 1826.709
Seventh 69.33 13.167 1.172 20.657 14.361 -5.758 20.118 18.190 57.427 1113.563
Eighth 82.67 13.500 1.216 21.433 14.900 -5.758 20.658 19.150 39.237 536.123
Roof 96.33 13.833 1.256 22.138 15.390 -5.758 21.148 20.088 20.088 277.877
Wind (East - West Direction)
FloorHeight
(ft)
TributaryHeight
(ft)Kz
qz(psf)
Windward(psf)
Leeward(psf)
Total(psf)
StoryForce(kips)
StoryShear(kips)
OverturningMoment (ft-
k)
Ground 0.00 0.00 0.849 0.00 0.00 0.00 0.00 0.000 474.909 23767.869
Second 14.33 13.667 0.849 14.964 10.140 -9.353 19.493 57.664 474.909 23767.869
Third 25.33 11.000 0.948 16.709 11.322 -9.353 20.675 49.228 417.245 17927.222
Fourth 36.33 11.000 1.023 18.031 12.218 -9.353 21.571 51.361 368.017 13608.280
Fifth 47.33 11.000 1.081 19.053 12.910 -9.353 22.263 53.010 316.656 9889.078
Sixth 58.33 11.000 1.130 19.917 13.496 -9.353 22.849 54.404 263.646 6650.892
Seventh 69.33 13.167 1.172 20.657 13.997 -9.353 23.350 66.551 209.242 4050.000
Eighth 82.67 13.500 1.216 21.433 14.523 -9.353 23.876 69.770 142.692 1947.879
Roof 96.33 13.833 1.256 22.138 15.001 -9.353 24.354 72.922 72.922 1008.730
8/12/2019 Follett Tech 3
35/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page35
SeismicLoadingCoefficientsandStoryResults
SeismicParametersforWashingtonParkCondominiums
Ss S1 SiteClass Fa Fv Sds Sd1SeismicDesign
Category
SeismicUse
Group
0.128 0.058 C 1.6 2.4 0.137 0.093 B I
I R Cu Ta TL Ts Cs k V(kips)
1 3.5/5 1.7 1.082 12 0.6333 0.01706 1.291 248.3248
BaseShearCalculation
FloorHeight
(ft)
Tributary
Height
(ft)
DeadLoad
(kips)wxhx
k Cvx
Lateral
Force
(Fx)
Story
Shear
(Vx)
Overturning
Moment
(ftkips)
Ground 0.00 7.167 1939.190 0 0 248.325 248.325 15451.152
2nd 14.33 13.667 2050.530 63764.65 0.0291058 7.228 248.325 15451.152
3rd 25.33 11.000 1501.591 97419.23 0.0444676 11.042 241.097 12345.445
4th 36.33 11.000 1501.591 155186.6 0.0708359 17.590 230.055 9754.098
5th 47.33 11.000 1488.721 216478.4 0.0988129 24.538 212.464 7320.232
6th 58.33 11.000 1488.721 283517.5 0.1294133 32.137 187.927 5118.067
7th 69.33 13.167 1540.881 366773.9 0.1674162 41.574 155.790 3227.610
8th 82.67 13.500 1540.881 460325.8 0.2101186 52.178 114.217 1609.312
Roof 96.33 13.833 1503.864 547324.3 0.2498296 62.039 62.039 858.184
Total W= 14555.970 2190790
8/12/2019 Follett Tech 3
36/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page36
AppendixC:CenterofMassandRigidity
Area1
Area2Area3
Area5Area4
(0,0)
8/12/2019 Follett Tech 3
37/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page37
TorsionConstants
FloorCenterofRigidity CenterofMass
IX (in4) Iy (in
4) IP (in4)
XR(ft) YR(ft) XR(ft) YR(ft)
Second 104.92 39.89 102.3 34.7 2837888.75 353494.66 3191383.41
Third
104.92
39.89
102.3
34.7
2837888.75
353494.66
3191383.41
Fourth 104.92 39.89 102.3 34.7 2837888.75 353494.66 3191383.41
Fifth 104.92 39.89 102.3 34.7 2837888.75 353494.66 3191383.41
Sixth 104.92 39.89 102.3 34.7 2837888.75 353494.66 3191383.41
Seventh 104.92 39.89 102.3 34.7 2837888.75 353494.66 3191383.41
Eighth 104.92 39.89 102.3 34.7 2837888.75 353494.66 3191383.41
Roof 104.92 39.89 102.3 34.7 2837888.75 353494.66 3191383.41
8/12/2019 Follett Tech 3
38/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page38
AppendixD:PortalFrameAnalysisCalculations
8/12/2019 Follett Tech 3
39/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page39
PortalFrameE
8/12/2019 Follett Tech 3
40/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page40
8/12/2019 Follett Tech 3
41/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page41
PortalFrameF
8/12/2019 Follett Tech 3
42/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page42
8/12/2019 Follett Tech 3
43/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page43
PartialPortalFrameA
8/12/2019 Follett Tech 3
44/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page44
AppendixE:TorsionalForceTables
8/12/2019 Follett Tech 3
45/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PA
B.Follett Page45
WindTorsionalForces
8/12/2019 Follett Tech 3
46/47
8/12/2019 Follett Tech 3
47/47
Technical WashingtonParkCondominiumsReport#3 Mt.Lebanon,PASeismicTorsionalForces