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Performance ofisolatedandfoldedfootings
Mahmoud Samir El-kady,Essam Farouk Badrawi 한국CDE학회 2017 Journal of computational design and engineering Vol.4 No.2
Folded foundationshavebeenusedasanalternativetotheconventional flat shallowfoundations,insituationsinvolvingheavyloadsorweaksoils. Theycanbegeometricallyshapedinmanyformsespeciallyforisolatedfootings.Thepurposeofthispaperisintroducinganalternativefoundation shapethatreducesthecostoffoundationsbyreducingtheamountofreinforcingsteelbyminimizingoreveneliminatingthetensionzones inthefoldedisolatedfootings.Also,achievinglowersoilstressesthroughchangingtheisolatedfootingshapewillconsequentlyreducetheexpected settlementsandthefootingstresses.Experimentalandnumericalstudiesareperformedon five (5)quarterscalefootingsofwhichone(1) footingof flat shapeistestedasareferencesampleandfour(4)footingsareoffoldedshapebyfoldinganglesof101, 201, 301, and401 withthe horizontal.Resultsshowedthatthefoldedisolatedfootingsachieveeconomicdesignbydecreasingthequantitiesofreinforcement.Italsoinduced lesssoilsettlements,andstresses.Inaddition,thetensilestressesinthereinforcedconcretefootingbodyarealsolessinfoldedisolatedfootings thanthe flat one.Resultsshowthatthefoldedisolatedfootinghaveabetterloadcarryingcapacitywhencomparedwiththeconventionalslab/flat footingofsimilarcrosssectionalareaforbothcasesofexperimentalandnumericalanalysis.
Foundations forlowcostbuildings
Sayed Abde lSalam,Mahmoud Samir El-kady 한국CDE학회 2017 Journal of computational design and engineering Vol.4 No.2
Attaining aneconomicalandsafedesignofstructuresisregardedasaprerequisiteforthestructuralengineer.Themarketpricesofreinforcingsteels havedramaticallysoaredinrecentyearsinternationally.Therefore,thepurposeofthecurrentpaperisnotjustreducingtheratioofreinforcing steelinthefoundationsforskeletonstructures,butratherminimizingthisratiothroughchoosingthemosteffectivefootingshape(folded stripfootings).Foldedfootingshavebeenusedasanalternativetotheconventionalrectangularstripfootings.Theheightofthestudiedmodel isten floors. Twodifferentfoundationsystemsareusedintheanalysisnamely;rectangularstripfootings,andfoldedstripfootingsrespectively. Bothfootingshapeswillbedesignedascontinuousfootingswithgridshapeunderthebuilding.Comparisonbetweenthetwosystems isalsopresentedregardingtheconcretesectionsandreinforcementratiounderthesameappliedloads.The finite elementanalysissoftware ADINAisusedinmodelingandanalysisofthestructuralandgeotechnicalbehaviorofbothtypesoffootings,withemphasisontheeffect ofchangingthefootingshapeonthestressesinthefootingconcretebodyandtheunderlyingsoils.Researchresultspresentstheinternalstresses withinthefootingandsoildomains,aswellasthecontactpressuredistributionforareinforcedfoldedstripfootingrestingondifferentsoil types.Theinfluence offoldinginclinationangle,andsoiltypeontheresultsarealsostudied.Resultsshowedthatfoldedstripfootingsareefficient inreducingtheamountofneededreinforcements,andsuchefficiency inreducingtherequiredsteelreinforcementinthefootingsisdepending ontheappliedfootingloads,andtosomedegreeonthesoiltypeandproperties.Reductioninthereinforcementratiobetweentherectangular andfoldedfootingtypesisabout26%infavorofthefoldedstripfootings.Acomparativeeconomicalstudyshowsthatthetotalcostof thereinforcedconcretesectionforthefoldedstripfootingsislessthanthetraditionalonebyabout18%.Thisdifferenceincostofbothtypesof footingsismainlyduetotherelativelysmallerinsteelreinforcementrationeededforthefoldedtypeascomparedwiththerectangularones. So, thefoldedstripfootingismoreeconomicalthantherectangularstripfooting.