This document provides background information and procedures for assessing the condition of parking structures. It discusses common deterioration modes in parking structures and appropriate non-destructive testing methods. Visual inspection revealed various concrete deterioration in 7 parking structures, with photos in an appendix. Covermeter, pull-out, pull-off, resistivity, ultrasonic, infrared, and permeation tests were identified as suitable non-destructive techniques for evaluating parking structures, though some have limitations regarding member access and orientation.

1. University of Toronto
Faculty of Applied Science & Engineering
Department of Civil Engineering
Project II: Deterioration Assessment of Parking Structures
CIV 1201H – Concrete Technology and Non-Destructive Testing
Prepared for: Dr. D. K. Panesar
By: Arman Khabbazian
Ali Elmizadeh
March 24th, 2015.

2. 2
Table of Contents
Table of Contents ...............................................................................................................................2
Background........................................................................................................................................3
Procedure..........................................................................................................................................6
Visual Inspection.............................................................................................................................6
Non-destructive Testing..................................................................................................................6
Condition Assessment.......................................................................................................................10
Discussion and Conclusions...............................................................................................................15
References: .....................................................................................................................................17

3. 3
Background
Parkingstructuresare consideredacritical componentof the infrastructure inhighlypopulated
urban areas.Theyprovide efficiencyinstoringalarge number of vehicles, aswellasprotectionagainst
harsh weatherconditions,suchasheavyrainfall,snow,hail,andhighorlow temperatures.The rapid
growthof the populationaroundthe GTA emphasizesevenfurtherthe importance of parkingstructures
inhightrafficareas. More fundingisbeingpouredintothe constructionof these beneficialstructures, as
the price of landrisescontinually.Onthe otherhand,aside fromconstructioncosts,parkingstructures
induce repairandmaintenance costsmuchhigherthanon-grade parkingspaces. Butinthe end,as this
metropolitanareagrowsrapidly,the benefits override the cost.Nevertheless,withthe aging
infrastructure aroundthe GTA,the repairand maintenance of parkingstructureshasgainedmore
importance.Assuch,the properassessmentof the conditionof these structureshasbecome critical,so
that adequate remediationmeasurescanbe undertakenfora safe utilization.
In orderto appropriatelyassesthe conditionof aparkingstructure andcome upwitha
restorationprogram,the type of parkingstructure mustbe identified.Intermsof exposure,parking
garagescan be undergroundorabove ground.Whetherthe structure isabove or below the ground
dictatesthe degree of exposure toharmful chemicals,freeze-thaw cyclesandgroundwaterseepage.The
criticalityof deteriorationprocessescausedbysuchagents/factorsultimatelydependsonthe
implicationtothe structural integrityof eachof the structural componentsof the garage. Parking
garagesstructural systems are mainly classifiedinto fivetypes:
 ReinforcedConcrete FlatSlab,whichconsistsof flatslabsthatreston reinforcedconcrete
columns bymeansof a drop panel.
 Reinforcedconcrete beamandslab- thissystemisusedtoattainlongerclearspansandis
commonlyutilizedinthe designof undergroundparkinglevelsof buildingsandindependent
structures.
 Post- tensioned structures- posttensioningcanbe usedincertainor all elementsof structures
inorder to reduce constructiondepthandcrackingof the members
 PrecastConcrete Structures- StandardT-beamsorslabsare usedto form the floorsof the
parkingstructure and maybe supportedbyavarietyof systemssuchas precastcolumns& walls,

4. 4
reinforcedconcrete columnsandwalls,orstructural steel frames.These designare usedwhere
longspansare requiredtominimizethe numberof columns
 Steel structures- structural steelframesare usedtosupportone or more typesof floorsystems,
and include reinforcedconcrete,precastconcrete slabsorT-Beamsormetal deckwith
composite concrete floor.
The damage resultingfromsulphateattack,alkali aggregate reaction,andfreeze-thawactionare
usuallyconsideredstructurallyinsignificant,asthe deteriorationcouldtake alongtime andthe extent
of itcouldnot pose a considerable problemtothe integrityof the structure.Rapidandprogressive
structural deteriorationof parkinggaragesismainlycausedbycorrosionof the reinforcingsteel inthe
concrete, as alreadymentioned,orof the steel tendonsinpost-tensioned orpre-tensionedconcrete
(TorontoMinistryof Housing,1988).
As showninFigure 1, the corrosionrate of steel isafunctionof the alkalinityof itsenvironment.
Concrete containslarge amountsof lime whichmakesthe environmentof concrete stronglyalkaline,
havinga pH of between12and 13. Thus,steel embeddedinconcrete normallydoesnotrust.If,
however,the lime inthe concrete isleachedoutorneutralizedbycarbonation(the transformationof
the lime intocalciumcarbonate througha reactionwithcarbondioxide),the passivestate of the steel is
terminatedandcorrosionwill occur. Evenif the environmentishighlyalkaline there isstill ariskof
corrosionif chloride ionsare present.Theyactas catalystsforcorrosion and once the processhasbegun
it doesnotdiminishwithtime ( G.G.Litvan,1982).
Harsh wintersandlow temperaturesin
Ontario,require the continuous use of deicing
saltson the roads inorderto facilitate traffic
and keepthe roadsoperational.These saltsare
chlorine basedandwhenmixedwithsnowand
ice,theyare transportedintoparkinggarages
by movingvehicles.Chloridesinfiltrate the
concrete and reachthe embeddedsteelinarelativelyshorttime (dependingonhow porousthe
concrete isand howclose to the surface the rebar is).Because of steel corrosion,the volume of the
corrosionproductsincreasesanditcausescracking of concrete.Thiswill breakthe bondbetween
concrete and steel andthe loadcarryingcapacity of the structure starts diminishingquickly.Eventually
Figure 1 - Corrosion rate in steel ( G.G. Litvan, 1982)

5. 5
concrete cracks become biggerandwiderascorrosioncontinuesandspallingstartstooccur which
exposesreinforcingsteeltothe environmentof saltandmoisture (G.G.Litvan,1982).
Figure 2 - Effect of corrosion in reinforced concrete (G.G. Litvan , 1982)
Duringthe firstyearsof a parkingstructure,no delaminationswill occureventhoughmoisture andsalts
are accumulatingonthe top steel inthe concrete slab.Duringthistime the passivityof the steel has
beenmaintained.Whencorrosionoccurs,itisan indicatorthatpassivityof steel islost. Delamination
will take time tooccur and ithappens whenthe corrosionproductsexerttensile forcesbiggerthan
concrete’stensilestrength.Usuallythe topsurface delaminationof the slabhappensmuchearlierthan
the underside delamination. The reasonsforperiodicinspectionof parkinggaragesare to detect
deficienciesanddeteriorationsrange fromthe needforsafety(relatedtothe load bearingcapacityof
the parkingfloor),tothe needfortimelyinformationonthe conditionof the structurestoensure
promptand cost-effectivemaintenance andrepair.Evaluationproceduresusually involve avisual
inspectiontoidentifythe problems,anddetailedmethodswhichinclude anexperiencedengineerand
NDT methodstohelp inmakinga diagnosisof the structure condition (TorontoMinistryof Housing,
1988).
Assessmentandtestingtodetermine the integrityof parkinggaragesare done byan experienced
engineerafteravisual inspection.The followingpagespresentapossible approachanddetailedsteps
includingphotographsof selectedstructurestothe monitoringandNDTproposal of parkinggarages.

6. 6
Procedure
Visual Inspection
The visual inspectionof parkingstructuresprovidesanexternal view of the conditionof
concrete members.A thoroughinspectionmustalwaysbe the startingpointforanycondition
assessmentof concrete structures.Basedonthe type anddegree of deteriorationof concrete noticed,it
can be decidedwhetherthe conditionassessmentshouldbe takenfurthertotestingmethods,inorder
to geta more indepthviewof the conditionof the structure at hand,and alsowhichtypesof testingare
adequate foruse.If certainparts of the garage have limitingaccess,certaintestscannotbe performed.
Thisservesas one of the challengeswithvisualinspection.Anotherchallenge wouldbe thatitrequiresa
well experiencedeye tospotthe typesof deterioration,the severity, itsimplicationtothe overall
structural integrityof the garage,coupledwithasoundengineeringjudgementtomake the appropriate
callsfor action.
For the purpose of thisreport,sevenparkingstructuresaroundthe GTA were visited.These
garageswere differentintermsof exposure andalsostructural type. The visual inspectionyieldeda
varietyof deteriorationmodesinconcrete memberswithdifferentextentsof damage. The picturesof
the deteriorationstakenduringthe site visitscanbe foundin the Appendix sectionof the report.They
were furtheranalyzedtoidentifythe type of deterioration,the possible cause andremediation
measures.
Non-destructive Testing
Basedon the visual inspectionresults,itcanbe decidedwhethernon-destructive testingis
requiredfora betterunderstandingof the conditionof eachparkingstructure.If visual inspectionyields
goodresultswithminordeteriorationsinconcrete whichhave nostructural integrityimplications,then
testingonthe concrete becomesunnecessary.Also,basedonthe type of deteriorationnoticedandthe
type of structure along withitsgeometrylimitations,the typesof non-destructivetestingmethodscan
be suggested. The followingare the teststhatare applicable toparkingstructures.The limitations
mentionedforeachone of themare those that arise fromtheirapplicationtoparkingstructures,and
not theirgeneral limitations.

7. 7
CovermeterSurvey
A covermetercanbe usedto surveythe structure inorderto accuratelydetermine the location,size and
depthto the steel reinforcement.Thisapparatusisable toestimate sizesof reinforcingbarsbetween
3/8 and 2 inches,a range whichincludesthe barsizesusedinparkinggarages.(Lauer,2004) Basedon
the locationandsize of bars detected,the structural engineercanjudge whetherthe current
reinforcementinthe deterioratedareaisenoughtoprovide adequatestructural support.Also,basedon
the amountof concrete coveroverthe reinforcingbars,the appropriate repairmeasurescan
undertakentoincrease the concrete coverwhere itisbelow requirementfordurability.Lastly,
covermetersare adequate foruse inparkingstructuresbecause theyrequire onlysingle-sideaccessto
the concrete memberof the structure,as undergroundparkinggaragesgenerallydonotprovide
exterioraccess.
Pull-OutTest
Pull-outtestcanbe performedtoestimate the in-situcompressive strengthof concrete in
parkingstructures.Asthistestis usuallyusedtodetermine the in-place strengthof concrete duringthe
constructionphase,forexistingstructures,the pulloutmechanismmustbe post-installedbydrillinginto
the concrete surface.(Carino,2004) Basedon the resultsof the test,it can be judgedwhetheracertain
concrete memberrequiresstructural restoration.The pull-outtestcanbe utilizedinparkingstructures,
since itrequiresone sidedaccesstothe membertobe tested.
Pull-OffTest
Justlike the pull-outtest,pull-offtestcanbe usedto estimate the compressive strengthof the
concrete inparkinggarages.It isbasedon the conceptthat the tensile force requiredtopull ametal
disk,togetherwithalayerof concrete surface,isrelatedtoitscompressive strength.(Hendersonetal,
2004) Thismethodisadequate forparkingstructuressince itusedforexistingstructures,andnotduring
the constructionphase.Justlike the previoustests,pull-off testrequiresone sidedaccesstothe
concrete to be evaluated.
ResistivityTest
Since reinforcingbarcorrosionisthe mostproblematicdeteriorationmode inparking
structures,testingforcorrosionbecomesapriority.Totestforthe likelihoodof corrosionin
reinforcement,the Half-cellPotential Testcouldbe used.However,thismethoddoesnotprovidedirect

8. 8
informationonthe actual rate of corrosioninrebars.Therefore,Concrete ResistivityTest canbe usedin
conjunction withHalf-cell Test.Thistestreliesonthe factthat the rate of corrosiondependsonthe
electrical resistance of the concrete,whichreflectshow easilythe harmful ionstravelthroughthe
concrete towardsthe reinforcement. Asthe presence of reinforcementinthe concrete affectthe results
of the resistivitytest,the testshouldbe performedmidwaybetweentwobars.Inparkingstructures,the
depthof cover isgenerallybetween35-45mmand the rebarsare closelyspaced.Hence,the results
mustbe adjustedaccordingly,providedthatthe layoutof the reinforcementisknown. (Carino,2004) In
the aspectof access andorientation,bothof these testshave nolimitations.
UltrasonicPulse VelocityTest
Thistestwouldbe very useful forparkingstructuresconditionassessmentssinceitcanprovide
informationaboutvariouspropertiesof concrete members.First,itcanestimate compressive strength
of the concrete forsituationswhere structural restorationof garage iscontemplatedupon.Second,it
providesinformationaboutthe extentof deteriorationinconcrete asitcan estimate crackdepths.
Third,it can serve asan indicatorfor durabilitypropertiesof the concrete forregionsthathave no
visible cracks.(Malhotraetal,2004) Since inparkingstructures,especiallythose underground,there is
not alwaysdouble sidedaccess,the transmitterandreceivercanbe placedonthe same side.However,
appropriate adjustmentsmustbe made tothe resultsto accountfor the effect of reinforcingbarsinthe
concrete member.
Infrared Thermography
Thistestcan be usedinparkinggaragesin orderto detectsubsurface anomaliessuchasvoids,
cracks and delaminations.Sinceitusesthe emissionof thermal radiationinconcrete,itrequiresa
thermal gradientbetweenthe twooppositesurfacesof the concrete member(Weil,2004).Therefore,
for parkingstructure componentswhichare notexposedtothe sun’sradiation,uniformheatingof the
concrete can be achievedusingasetof heaters.Intermsof access and orientation,thistesthasno
limitations.
PermeationTests
Whetherundergroundorabove ground(coveredoruncovered),parkinggaragesare exposedto
several deteriorationhazards.The durabilityof the concrete againstthese agentsisrelatedtoits
transportproperties.Several permeationtests learnedinCIV 1201 are available toinvestigatethese
propertiesof the concrete.Basedonthe resultsfromthese tests,itcanbe judgedwhetherthe concrete

9. 9
memberrequiresremediation measurestoimprove itsdurabilitysuchaspatching,installingwaterproof
membranes,orapplyingsealanttothe concrete surface.The mostadequate forthe investigationof
parkingstructureswouldbe:
Initial SurfaceAbsorption Test (ISAT).Thistestwouldbe useful inmeasuringthe amountof
waterthat the concrete absorbsby capillaryactiontofill itspores.(Hendersonetal,2004) It shouldbe
mentionedthatISAThaslimitationswhenitcomestoitsapplicationtoparkingstructures.First,it
requiresaccesstoboth sidesof the concrete memberasthe apparatusneedstobe clamped.Second,it
requiresahorizontal surface totestitsabsorption,aswateris notpressuredandvertical orinverted
orientationswouldaffectthe resultsof the test.Lastly,ISATresultsare affectedbythe surface coating
of the concrete.Usually,undergroundparkinggaragesinresidential unitshave paintedwallsand
columns.Hence,ISATwouldbe useful forinvestigatingthe transportpropertiesof onlyintermediate
slabsand otherhorizontal surfaces,providedthattheyare not coated.
AutoclamSorptivityTest. Thistestalso measuresthe waterabsorptionof the concrete,but
wouldbe evenmore adequate forparkingstructuresdue toitsreducedlimitationsof application.First,
it doesnotrequire accessto bothsidesof the memberasthe apparatus isglue to itssurface.Second,
the waterto be absorbedbythe concrete surface iskeptunderpressure.Assuch,the resultsof the test
are notaffectedbythe orientationof the concrete surface (i.e.vertical orinverted).Therefore,thistest
isapplicable toall concrete membersof parkingstructures,once againprovidedtheyare notcoated.
Figg WaterAbsorption Test(FWAT).Thistestisbasedon the same principle as the previoustwo,
but itis an intrusive testsince itrequiresdrillingintothe concrete member,whichcouldserveasa
limitationinsituationswhere the structural integrityof the concrete membertobe testedcouldbe
compromised.Besideshavingnolimitationsintermsof accessand orientationof the member,FWATis
not affectedbythe coatingsandsurface layerof the concrete in parkingstructures.
AutoclamWaterand Air Permeability Tests. These testsmeasure the amountof wateror air that
entersthe concrete due toa pressure gradient.(Hendersonetal,2004) Hence,theirresultsare not
affectedbythe orientationof concrete surface.Also,since itisthe same autoclamapparatus,ithas no
limitationintermsof accesstothe sidesof the concrete member.Butjustlike the othernon-intrusive
tests,itrequiresanexposedconcrete surface andalsoitsresultsare affectedbythe concrete surface
layercondition.

10. 10
Figg Air PermeabilityTest. Since itusesthe same apparatusas the figgwaterabsorptiontest,
thistesthas no limitationsintermsof access,orientationandcoatings.Butagain,itisan intrusive test
whichcan serve as a limitationtocertainsituationsinparkingstructures.
Schonlin Test and SurfaceAirflow Test. The air permeabilityof the concrete ismeasuredusing
apparatusesthatare attachedto the concrete surface by meansof vacuum.As such,theyrequire no
permanentattachmentorclamping,andalsohave nolimitationsinthe aspectof orientationandaccess
sidestothe concrete memberof the garage.However,since theyare notintrusive tests,theyrequire an
exposedconcrete surface.
ConditionAssessment
The followingwerethe resultsof the visual inspectionperformedineachof the sites.Basedon
these results,the appropriatenon-destructivetestingmethods were suggestedforeachof the parking
structures.However,insome cases,the conditionassessmentarisingfromthe use thisprocedure might
not be enoughtodecide whetherrehabilitationordemolitionactionmust be taken.Assuch,destructive
testingmethodscanbe utilizedtoprovide definite resultsforadequate decisionmaking.
The followingwerethe resultsof the visual inspectionperformedineachof the sites.Basedon
these results,the appropriatenon-destructivetestingmethodswere suggestedforeachof the parking
structures.
Parking Structure #1:
Thisstructure was locatedat 210 Markland Drive,
Etobicoke.The site wasvisitedonMarch 10, 2012 at 2:04 pm. The
weatherwashumidandcloudy and the temperature was20°C.In
termsof exposure,thisstructure wasanunderground garage.As
for itsstructural type,thisgarage was composedof concrete
reinforcedslabsrestingonconcrete columnswithdroppanels.
Once the structure wasexamined,afew areasof deterioration
were observed,withmechanismssuchasefflorescence,cracking,seepage andleakage,rustingof rebar,
and pitting.Figure 3showsthe deterioration of the wall inthe bottomof the stairwell,justbefore
enteringthe parkinggarage.The whole areawasmoist,especiallythe bottommeterof the wall.Thisis
due to seepage of the groundwatercomingfromthe soil behindthe wall.The picture showsalocation
Figure 3 - Popout

11. 11
where pittinghastakenplace inthe formof small popouts.Peelingof
paintwas observedinall the wall areabefore enteringthe garage.
Some delaminationinthe wall nexttothe stairwell wasalsoobserved,
but thiswaslocalized(Figure4).The overall structural integrityof the
parkinggarage was foundto be adequate.The concrete damages
observedmostlyaffectedaestheticappearance of the structure.
Remediationmeasurescanbe undertakentorestore it,suchas
repainting,groutingandsealing.
Parking Structure #2:
The structure waslocatedbelow Bahen
Centre,224 Huron Street,Toronto.The site was
visitedonMarch 16, 2012 at 1:40pm, and the weather
was sunnyanddry and the temperature was18 °C.
This4 level undergroundgarage wasconstructed
usingcast-in-place concreteslabsrestingon
reinforcedconcrete columnswithdroppanels.During
the visual inspection,the mostprevalentformsof
deteriorationwere diagonalcracking,seepage,
stalactites,pop-out,corrosionandpeeling. Figure 5
showsa diagonal crack of the retainingwall inthe entrance rampof the garage.Thiscrack was observed
approximatelymid-wayintothe entrance of the garage so thismode
of failure could be explainedbythe factthat the pressure of the soil
behindthe wall whichisexertedatthe lower1/3 of the wall’sheight
exceedsthe concrete loadbearingcapacity.A poorconcrete mix or
batch couldbe the reasonforthe deteriorationobserved.
In the cornerof the firstlevel (Figure6) there isan evidentsignof
leakage of waterfromthe above grade.The formationof blackmould
on the wall suggeststhatthisisan ongoingproblemandfaulty
drainage isthe cause of the deterioration.The iciclelook-alikepicture
observedinFigure 7is calledStalactite.Itwasseenonthe ceilingof
the firstlevel of the parkinggarage.The stalactitesfollowedalong
Figure 4 - Delamination
Figure 5 - Diagonal cracking
Figure 6 - Black mold

12. 12
crack onthe ceilingslabwhichsuggeststhatwater
permeatedthroughthe topfloorandas it evaporated,
the mineral formationwasleftbehind.A possible
explanationforthe crackwouldbe a thermal gradient
whichisthe difference intemperature betweenthe core
and the surface of the slabwhenconcrete waspoured.
Alsoonthe lowerlevels(P3-P4) minorcorrosionstains
were observedonthe wallsfromall 4 sides.Deicingsalts
have increasedthe chloride ionconcentrationandthe
steel hasbeendepassivated.Althoughthe structural integrityof the membersseemedintact,we know
fromexperiencethatcorrosionprogressesrapidlyanditwill be matterof time before we observe
delaminationand spalling. Despite the visualminordeteriorationsthatwere mentionedabove,the only
immediate recommendationistorepairthe leakage problemonthe firstfloorandprovide athorough
cleaningof the mold.Alsoathoroughrepairof the crack where the stalactitesare formedisnecessary.
Parking Structure #3&4
These structuresare locatedinMississauga(
Bloorst and Rathburn rd) inthe Square One
shoppingcentre.We mainlylookedatBay
and Wal-Mart parkinggarages.Theyare 2
and 3 storieshighrespectively. Theywere
visitedonMarch 16th
at 1 PM andthe
weatherwassunnyanddry witha
temperature of 20 °C. These garageswere
constructedwithprecastconcrete structures
where standardT-beamsandslabsare used
to formthe floors.The first level parking
wallswere foundtobe inan almostexcellentconditioninbothparkinggarages.There were visible
hairline cracks onclose inspectiononall wallsatfirstfloors.The mainproblemwithsome of the
external columnsandstairwells connectingThe Baystore withthe parkinggarage wassegregationand
honeycombing.Dryingshrinkagecrackswere observedonprecastslabsandtheydidnotseemto follow
a particularpattern.It wasobservedthatthe structural integrityof the parkingfacilitiesweresound
Figure 7 - Stalactite
Figure 8 - View of P2 Level

13. 13
since there were noobvioussignsof performance deficiencies. Onthe above grade exposedparking
space,there were visible signsof efflorescence andchalking
on the parapetwalls.Pittingwasa commoncharacteristic
of all the wallsespeciallythe onesabovegrade onboth
parkinglots. Corrosionwasobservedonthe toppart of the
parapetwallsveryclose tothe surface and some of the
stirrupswere exposed.Thisisdue tothe lack of adequate
coverthat neededtobe providedduringconstruction.The
chloride ionsbroughtinbythe movingvehicleshave
startedto corrode the stirrupsand it isa matter of time
before visible ruststainsappearonthe sidesof the walls.
Major cracking wasobservedinone staircase andslab
connectionin Wal-Mart.The slab nearthe edge was
cracked (>5mm) and delaminationwasobserved.Thiswasalocalizedeventanda poorconstruction
methodisto be blamedsince there wasnowateror de-icingsaltssigns. Onthe entrance rampof the P2
level of Baygarage there was corrosionat columnto
beaminterface andalsosignsof efflorescence and
spalling.The mainreasonforthisseemedtobe the
extensive leakage of waterwithchlorideionsfromthe
top exposedlevel.There ispoordrainage providedand
the jointisnot sealedproperly.Althoughthe structural
integrityof the beamseemstobe adequate,further
structural analysisisrecommendedtoproperlyassess
the load carrying capacityof the memberis
recommended.
Similardeteriorationmodeswere observedinthe othertwoparkingstructures.Leakage due topoor
drainage,seepage of groundwaterfromthe soil behindthe wall andde-icingsalts,were the main
reasonsforthe deteriorationmechanisms. Onall the structuresvisitedthere isneedforrepairforboth
aesthetical reasonsandpreservationof structural integrity.The onlystructure thatvirtuallyshowedno
signsof damage was the LesterPearsonAirportterminal 1.There were some signsof minorrepairand
patchesinthe 8 story parkingstructure whichsuggeststhat itis beingperiodicallyandproperly
Figure 9 - Honeycombing
Figure 10 - Rusting of stirrups

14. 14
inspectedandalsobetterconstructionmethodswere used. The table belowsummarizesthe modesof
deteriorationobservedonall the parkingstructures.
Deterioration
Mode
Markland Airport Ikea Wal-Mart Bay Guelph Bahen
Diagonal
cracking
X X X X X
Corrosion X X X X X X
Efflorescence X X X X X X
Spalling X
Delamination X X
Pitting X X X X X
Leakage X X X X
Seepage X X X
Segregation X X
Stalactites X X
Peeling X X
Shrinkage
cracking
X X
Blistering X
Map cracking X
Scaling X
Basedon the deteriorationmodesdetectedduringthe visual inspection,the following non-destructive
testswere suggestedforeachsite:
NDT Markland Airport Ikea Wal-Mart Bay Guelph Bahen
Covermeter X X X X X X
Pull-out
Pull-off X X
Half-Cell X X X X X
Resistivity X X X X X X
UPV X X X X X
Infrared X X
Autoclam
Sorptivity
Figg Water
Absorption
X
Autoclam
Water/Air
Permeability
X X
Figg Air
Permeability

15. 15
Discussionand Conclusions
Duringthe literature review,nonational orinternational codesorformal guidelinesfornormal
practicesinassessing,managingandtestingparkingstructureswerefound. Eachpaperauthorhad their
owncriteriafor assessingconcrete condition.Inrelevance toSouthern Ontario,there wasfoundashort
reportcompilingimportantinformationaboutparkingstructure investigationputforthbya committee
of OntarioMinistryof Housingin1988. It providedconcise informationaboutmodesof deteriorationin
parkinggaragesin Ontario,focusingmore oncorrosionof reinforcingbarsasthe mainconcern forthis
type of structure.
Severityof exposure conditionstoenvironmental factorsof parkinggaragesishigherthanin
mostother buildings.Inwinter,road saltpenetratesthe concrete causingcorrosionof reinforcingsteel
and extremesof temperature andhumiditywithinparkinggaragestendstopromote further
deterioration.In industry,several restoration companieshave theirownsetof guidelinesforstandard
practicesinconcrete conditionassessmentandclassification.Accordingtothe classification,the
engineercanmake aninformeddecisionastowhethertotestthe structure andevenwhattypesof
testingmightbe necessaryforanin depthview of the conditionof the parkingstructure. Therefore,it
remainsupto engineerto decide whatclassdoesacertainsituationbelongstoandwhat testing
methodsshouldfollow.
Some recommendationsintermsof prolongingthe life of parkingstructures putforthfromourteam
are :
 Provide cathodicprotectionof reinforcingsteel inparkinggarages
 Install waterproof membranesontopsurface of slabsto preventsaltandwaterpenetration
 More rigorousinspectionduring construction
 Increasingconcrete coverwouldslow downthe penetrationof chloride ionsandother
deleteriousmaterials
 Maintenance andinspectionsof the parkinggaragesshouldbe done yearly
 Excellentdrainageshouldbe maintainedatall timesandmonthlyinspectionsandcleaningof
drains isrecommendedtopreventwaterponding,etc.
As forthe challengesincontextwiththe non-destructivetestingof concrete inparking
structures,accessibilitytobothsidesof the structure remainsamajorone.Thisis typical for
undergroundparkinggarages.Assuch,the testsare to be selectedtoaccountforthislimitation.

16. 16
Anotherchallenge wouldbe performingthe NDTmethodswithminimaloperational disruptionstothe
parkingstructure.The testingtechnicianmustcoordinate withthe managementpersonnelof the
structure for a safe and time efficientevaluationof the parkinggarage.Lastly,decidingwhethertouse
non-intrusive orintrusiveNDTwouldserve asachallenge.There’satrade-off betweengettingbetterin
depthresultsusingintrusive NDTmethodsandkeepingthe structure intactwithnoincurreddamage as
the managementwouldusuallyprefer.Therefore,itrequiresawell experiencedengineertoproperly
assessthe situationandmake the necessarydecisionswhile keepingthe managementinformedof the
proceedings.

17. 17
References:
Litvan, G.G.(1982). Evaluation and repair of deteriorated garage floors. CBD 225, Division of
Building Research, National Research Council Canada, Ottawa.
Advisory Committee,(1988). Deterioration, Repair and Maintenance of parking Garages.
Minisitry of Housing, Ontario Buildings Branch.
Lauer,K.R.(2004).Magnetic/Electrical Methods. Handbook on nondestructive testing of concrete,
(2nd ed)., V. M. Malhotra and N. J. Carino, eds., CRC, Boca Raton, Fla.
Carino, N.J.(2004). Pullout Test. Handbook on nondestructive testing of concrete, 2nd Ed., V. M.
Malhotra and N. J. Carino, eds., CRC, Boca Raton, Fla.
Weil,G.J.(2004). Infrared Thermographic Techniques. Handbook on nondestructive testing of
concrete, 2nd Ed., V. M. Malhotra and N. J. Carino, eds., CRC, Boca Raton, Fla..
Henderson,G.D.(2004).Pull-Off Test and Permeation Tests. Handbook on nondestructive testing
of concrete, 2nd Ed., V. M. Malhotra and N. J. Carino, eds., CRC, Boca Raton, Fla.

18. 18
APPENDIX : ASSESSED STRUCTURES
Square One Walmart ParkingGarage
-Location:MississaugaCityCentre
-Built:1995
-Height:3 stories

19. 19
Square One Bay ParkingGarage
-Location:MississaugaCityCentre
-Built:1994
-Height:2 stories

20. 20
PearsonAirportTerminal 1ParkingGarage
-Location:Malton,Mississauga
-Built:1960
-Height:8 stories

21. 21
364 WaterlooAvenue
-Location:Guelph,Ontario
-Height:1 story

22. 22
BahenCentre
40 St.George Street,Toronto
-Fullyoperational in2005( builtin2002)
-4 levelsunderground

23. 23
IkeaStore
1475 The Queensway ,Etobicoke
-Builtin1999
-1 levelsunderground andone above grade