ECS338 Tutorial on REINFORCED CONCRETE Foundation DESIGN PDF

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ECS338 Tutorial on REINFORCED CONCRETE Foundation DESIGN...

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DESIGNOFREINFORCEDCONCRETEFOUNDATION

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LEARNINGOUTCOMES: Attheendofthistutorial,studentshouldbeableto: 1. Definetypesoffootingandtheirapplication. 2. DesignthepadfootingusingEC2. 

 ANSWERALLQUESTIONS(CO1:PO1) QUESTION1 Asquaresectionpadfootingwithselfweightof200kNisdesignedtoresistloadsfrom columnwith 300mmx 300mmsquaresection.Thecolumncarries unfactored permanent action and unfactored variableactionof500kNand 200kNrespectively.Resultfromstandard penetrationtestshowsthat thevalueoffirmsoilwithsafebearigpreassureis250  ⁄ .Usingthefollowingdata:  Unitweightofconcrete 25  ⁄   Characteristicstrengthofreinforcement 500  ⁄  Characteristicstrengthofconcrete 30  ⁄   Diameterofmainreinforcement 25 Nominalcover 40 Padfootingbaseheight(assume) 600  a) Determineasuitablebasesizewidthofthepadfooting.Designthemainreinforcementbars requiredforthepadfooting. (12marks) b) Checkthepadfootingasdesignedin(a)againstpunchingshear. (8marks) c) Sketchsuitablereinforcementdetialsforthepadfooting. (5marks)  QUESTION2 Thepadfootingisrequiredtoresistacharacteristicpermanentactionof450kNandcharacteristic variableactionof350kNfrom280mmsquareincrosssectionofcolumn.Thecolumnisrestedona padfootingof380mmthick.Use  500  ⁄ ,  30 ⁄ ,concretecover  35 andbardiameter 20  a) Evaluatewhetherasquarebasedimensionof2.1misadequateifthesafesoilpressureis 200 ⁄  .Assumingafootingselfweightis50kN. (4marks) b) Takingabasesizea1.8msquare,calculatethebendingreinforcementbarrequiredforthe padfooting. (16marks) c) Determinethestrengthofthepadfootingduetomaximumshearforce. (5marks)   ECS318/NSH/MAY‐OCT20111

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TUTORIAL5

DESIGNOFREINFORCEDCONCRETEFOUNDATION

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QUESTION3  Anaxiallyloadedcolumnwithacross‐sectionof400mmx400mmcarriesunfactoredpermanent actionof975kNandvariableactionof300kN.Thiscolumnissupportedbyasquarepadfootingwith theoveralldepthof600mm.Assumetheself‐weightofpadfootingis130kN.  Thedesigndataareasgivenbelow: Unitweightofconcrete 25  ⁄  Characteristicstrengthofreinforcement  500 ⁄  Characteristicstrengthofconcrete  35 ⁄   Safebearingpressureofsoil 200  ⁄  Diameterofmainreinforcement 20 Exposurecondition 2  a) Selectthe appropriatesizeofthepadfootingtocarrytheaxialloadstransferredfromthe column. (3marks) b) Calculatethemaximumbendingmomentactingonpadfooting. (5marks) c) Designthemainreinforcementbarsrequiredbythepadfootinginxandydirection. (4marks) d) Checkthepadfooting’sresistantagainstpunchingshearat2.0dfromthecolumnface. (10marks) e) Sketch the reinforcement detailing of the pad footing including plan view and the cross‐ section. (3marks)                          ECS318/NSH/MAY‐OCT20112

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TUTORIAL5

DESIGNOFREINFORCEDCONCRETEFOUNDATION

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QUESTION4  A300mmx300mmbracedcolumnisdesignedtocarry1005kNand200kNofunfactoredpermanent actionandunfactoredvariableaction,respectively.Asquarepadfootingwithselfweightof50kNis sittingonthesoilwith250  ⁄ safebearingpressure.Theoveralldepthfromthegroundsurface tothepadfootingis2800mmandthesoilisbackfilledthreequarterfromthedepth.  Thefollowinginformationisgiven: Characteristicstrengthofreinforcement  500 ⁄  Characteristicstrengthofconcrete  35 ⁄   Diameterofmainreinforcement 20 Nominalconcretecover 40 Diameteroflink10  a) Selectasuitablesizeandthicknessofthefooting. (5marks) b) Calculatethebendingreinforcementbarrequired,providethe reinforcementandcheckfor theminimumandmaximumpercentageofreinforcement. (15marks) c) Sketchthedetailingofreinforcementbarsforthefooting. (5marks)            

4H25

ECS318/NSH/MAY‐OCT20113

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TUTORIAL5...