Structural Engineering

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Draft


5.3Shear& Moment Diagrams 109



  1. BaseatBtheshearforcewas determinedearlierandwas equalto 2: 246 k. Based


ontheorientationof thexyaxis,thisis a negative shear.



  1. TheverticalshearatBis zero(neglectingtheweight ofAB)

  2. Theshearto theleftofCisV = 0 + (:749)(3)= 2 : 246 k.

  3. Theshearto theright ofCisV = 2 : 246 + 5:99 = 3: 744 k


Momentdiagrams



  1. At thebase:B M= 4: 493 k.ftas determinedabove.

  2. At thesupportC,Mc= 4 : 493 + (:749)(3)(


3


2


) = 7 : 864 k.ft



  1. Themaximummoment is equaltoMmax= 7 : 864 + (:749)(5)(


5


2


) = 1: 50 k.ft


Design: Reinforcement shouldbe placedalongthe berswhich areundertension,thatis on


thesideof thenegative moment


7


. The gurebelow schematicallyillustratesthelocation


of the
exural


8
reinforcement.

Example5-8: ShearMoment DiagramsforFrame


7
Thatis why in mostEuropeancountries,thesignconventionfordesignmoments is theoppositeof theone

commonlyusedin theU.S.A.;Reinforcement shouldbe placedwherethemoment is \postive".
8
Shearreinforcement is madeof a seriesof verticalstirrups.
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