Osterberg Cell Pile Load Test in Calgary, Alberta - A Case Study

Deepak Kumar, Joseph Yonan, A.F. Ruban

In the proceedings of: GeoRegina 2014: 67th Canadian Geotechnical Conference

Session: Earth Walls and Foundations

ABSTRACT: ThelocalgeologyofthenorthwestareaofCalgarywithintheouterBowRiverValleygenerallyincludesthepresenceoflacustrinesoilsoverlyingglacialtill.Theconsistencyofthelacustrinesoilinthisareaisfrequentlysofttofirmandisaccompaniedbyshallowgroundwateratsomelocations.Thethicknessofthelacustrinesoilsvariesinthisareaandposesfoundationchallenges,particularlywherehighstructuralloadsareanticipated.Accurateestimatesoffoundationdesignparametersinthesesoilscanhavesignificantimpactontheconstructioncostandperformanceoffoundations.Withtheseconsiderations,apileloadtestonaboredcast-in-placebelledpile,drilledthroughthelacustrinesoilsandbasedinglacialtillwasconducted,utilizinganOsterbergCell(O-Cell)method.ThetestwasconductedforTradesandTechnologyComplexdevelopmentofSouthernAlbertaInstituteofTechnology,locatedinnorthwestCalgary,Alberta.Thispaperpresentsacasehistoryofthepileloadtestanddiscussionofthefindingsofthepileloadtest.RÉSUMÉLagéologielocaledunord-ouestdeCalgarysetrouvantsurleborddelavalléedelarivièreduBowcomprendlaprésencedessolslacustrepar-dessusunecouchedetillglaciaire.Lacohérencedusollacustresdanscedomaineestsouventsoupleàfermeetestaccompagnéd'eauxsouterrainespeuprofondesàcertainsendroits.L™épaisseurdecessolsvariesdanscetterégionetposesdesdifficultéspourdesfondations,notammentpourceuxavecdeschargesdestructureélevés.Desestimationsprécisespourdesparamètresdeconceptiondebasedanscessolspeuventavoiruneffetsignifiantsurlescoûtsdeconstructionetlaperformancedesfondations.Enprenantcomptedeceseffets,untestdechargedepileaétémiseenplaceparforersurplaceenformedeclocheunpilierdanslessolslacustreetbasésdansletillglaciaire,enutilisantlemodèleOsterberg(O-cell).Cetestaétéconduitpouruneadditionpourl™institutdetechnologiedel™AlbertaduSud(SouthernAlbertaInstituteofTechnology),setrouvantdanslenord-ouestdeCalgary.Cetravailprésenteunepréhistoiredecetestdechargementdespiliersetlesdiscussionsdecesrésultats.1INTRODUCTIONPileloadtestsaregenerallyconductedtobetterestimatethepiledesignparameters,optimizetheprojectcost,ortobeabletousehigherresistancefactorsinthelimitstatesdesignmethodology.TheCanadianFoundationEngineeringManualallowstheuseofahigherresistancefactorwhendesignparametersareestimatedusingloadtestresults.WithanOsterbergcell(O-Cell),pileloadtestondeeppilescanbeconductedeconomically,comparedtotheconventionaltestingmethod.Theconventionalmethodgenerallyrequirestheuseofreactionpiles,whicharenotneededwhenusinganO-Cellmethod.GiventhattheO-CellutilizesreactionfromshaftfrictionabovetheO-CellandfromendbearingandshaftresistancesbelowtheO-Cell,testingashorterpileusingO-Cellmightnotprovideallthedesireddesignparameters.ThispaperpresentsacasestudyofapileloadtestthatwasconductedusinganO-CellatSouthernAlbertaInstituteofTechnology(SAIT)inCalgary,Alberta.Piledesignparametersestimatedfromtheloadtesthavealsobeencomparedwiththoseestimatedfromanalyticalorempiricalmethods.2BACKGROUNDThisloadtestwasconductedduringthefoundationdesignoftheTradesandTechnologyComplexwithinSAITcampusinnorthwestCalgary,Alberta(Figure1).Theentireprojectinvolvedconstructionofthreenewbuildingstructureswithpartialtofullbasements.Columnswithfactoredloadsofupto13,200kNweretobesupportedonpilefoundations.Intotal,theprojectinvolvedinstallationofmorethan400boredcast-in-placeconcretepiles.Consideringthenumberofpilesandtheirdesignloads,onepileloadtestwasconductedtoobtainamoreaccurateestimateofpiledesignparametersaswellastobeabletoutilizeahigherresistancefactorforpiledesign.

Please include this code when submitting a data update: GEO2014_105

Access this article:
Canadian Geotechnical Society members can access to this article, along with all other Canadian Geotechnical Conference proceedings, in the Member Area. Conference proceedings are also available in many libraries.

Cite this article: