Challenge

Project 1

PROJECT 1

Given,

Concrete floor thickness = 120 mm = 0.12 m

S.W of floor = 0.12*25 = 3 kPa

Floor finish and mech loads = 3 kPa

Live load = 5 kPa

Total load = 11 kPa

S.W of beam = 0.5*0.75*25 = 9.375 kN/m

Load on the indicated beam = (11*1.5)*2

=33 kN/m

Adding S.w of beam = 33 + 9.375 = 42.375 kN/m

  • Analyzing without considering load patterning
  • Solving by slope deflection method

    Fixed End Moments:

    MFAB = -(42.375*81)/12 = -286.03 kNm

    MFBA = 286.03 kNm

    MFBC= -286.03 kNm

    MFCB = 286.03 kNm

    MFCD = -286.03 kNm

    MFDC = 286.03 kNm

    MFDE = -286.03 kNm

    MFED = 286.03 kNm

    Unknowns : θa, θb, θc, θd, θe

    E = 10 GPa = 10 * 10^6 kPa

    = 1 *10^7 kPa

    I = (0.5*0.75^3)/12 = 0.0176 m4

    EI = 1.76*10^5 kNm2

    End Moments:

    Span AB :

    M ab = MFAB + (2EI/L)(2θa + θb)

    = -286.03 + (2*1.76*10^5/9)( 2θa + θb )

    = -286.03 + 78222.2 θa + 39111.1 θb

    M ba = MFBA + (2EI/L)(2θb + θa )

    = 286.03 + (2*1.76*10^5/9)( 2θb + θa )

    = 286.03 + 78222.2 θb + 39111.1 θa

    M bc = MFBC + (2EI/L)(2θb + θc)

    = -286.03 + (2*1.76*10^5/9)( 2θb + θc )

    = -286.03 + 78222.2 θb + 39111.1 θc

    M cb = MFCB + (2EI/L)(2θc + θb)

    = 286.03 + (2*1.76*10^5/9)( 2θc + θb )

    = 286.03 + 78222.2 θc + 39111.1 θb

    M cd = MFCD + (2EI/L)(2θc + θd)

    = -286.03 + (2*1.76*10^5/9)( 2θc + θd )

    = -286.03 + 78222.2 θc + 39111.1 θd

    M dc = MFDC + (2EI/L)(2θd + θc )

    = 286.03 + (2*1.76*10^5/9)( 2θd + θc )

    = 286.03 + 78222.2 θd + 39111.1 θc

    M de = MFDE + (2EI/L)(2θd + θe)

    = -286.03 + (2*1.76*10^5/9)( 2θd + θe )

    = -286.03 + 78222.2 θd + 39111.1 θe

    M ed = MFED + (2EI/L)(2θe + θd )

    = 286.03 + (2*1.76*10^5/9)( 2θe + θd )

    = 286.03 + 78222.2 θe + 39111.1 θd

    Equilibrium equations:

    Mab = 0

    78222.2 θa + 39111.1 θb= 286.03

    Mba + Mbc = 0

    (286.03 + 78222.2 θb + 39111.1 θa) + (-286.03 + 78222.2 θb + 39111.1 θc) = 0

    39111.1 θa + 1.56 * 10^5 θb +39111.1 θc = 0

    Mcb + Mcd = 0

    39111.1 θb + 1.56 * 10^5 θc +39111.1 θd = 0

    Mdc + Mde = 0

    39111.1 θc + 1.56 * 10^5 θd +39111.1 θe = 0

    Med = 0

    39111.1 θd + 78222.2 θe = -286.03

    Solving the unknowns,

    θa = 0.00418

    θb = -0.00105

    θc = 0

    θd = 0.00105

    θe = -0.00418

    On Substituting,

    Mab = 0

    Mba = 367.38 kNm

    Mbc = -367.38 kNm

    Mcb = 244.96 kNm

    Mcd = -244.96 kNm

    Mdc = 367.38 kNm

    Mde = -367.38 kNm

    Med = 0

    Analyzing individual members,

    AB:

    ∑Ma = 0

    (42.375*9*4.5)-9Rb + 367.38 = 0

    Rb1 = 231.51 kN

    Ra = 149.87 kN

    BC:

    ∑Mc = 0

    -367.38 + 244.96 – (42.375*9*4.5) + 9 Rb2 = 0

    Rb2 = 204.3 kN

    Rc1 = 177.09 kN

    CD:

    ∑Md = 0

    -244.96+367.38-(42.375*9*4.5)+9Rc2 = 0

    Rc2 = 177.09 kN

    Rd1 = 204.3 kN

    DE:

    ∑Me = 0

    -367.38+9Rd2-(42.375*9*4.5)=0

    Rd2=231.51kN

    Re=149.87kN

    • Max positive and max negative moment in each span (considering load patterning)
  • To get maximum positive moment in AB, AB and CD has to be loaded. Similarly to get maximum positive moment in CD, AB and CD has to be loaded with Live load including SW and DL. The remaining spans has to be loaded with self weight and DL alone

    S.W of floor = 3 kPa

    Mech services and Floor finishes = 3 kPa

    Total load = 6 kPa

    S.W of beam = 9.375 kN/m

    Load on the beam = (6*1.5*2) = 18 kN/m

    Adding S.W = 18 + 9.375 = 27.375 kN/m

    Live Load on spans AB and CD = ( 5*1.5*2) = 15 kN/m

    Total load on AB and CD = 15 + 27.375 = 42.375 kN/m

    Solving by slope deflection method,

    Fixed End Moments:

    MFAB = -(42.375*81)/12 = -286.03 kNm

    MFBA = 286.03 kNm

    MFBC= -(27.375*81)/12= -184.78 kNm

    MFCB = 184.78 kNm

    MFCD = -286.03 kNm

    MFDC = 286.03 kNm

    MFDE = -184.78 kNm

    MFED = 184.78 kNm

    Unknowns : θa, θb, θc, θd, θe

    E = 10 GPa = 10 * 10^6 kPa

    = 1 *10^7 kPa

    I = (0.5*0.75^3)/12 = 0.0176 m4

    EI = 1.76*10^5 kNm2

    End Moments:

    Span AB :

    M ab = MFAB + (2EI/L)(2θa + θb)

    = -286.03 + (2*1.76*10^5/9)( 2θa + θb )

    = -286.03 + 78222.2 θa + 39111.1 θb

    M ba = MFBA + (2EI/L)(2θb + θa )

    = 286.03 + (2*1.76*10^5/9)( 2θb + θa )

    = 286.03 + 78222.2 θb + 39111.1 θa

    M bc = MFBC + (2EI/L)(2θb + θc)

    = -184.78 + (2*1.76*10^5/9)( 2θb + θc )

    = -184.78 + 78222.2 θb + 39111.1 θc

    M cb = MFCB + (2EI/L)(2θc + θb)

    = 184.78 + (2*1.76*10^5/9)( 2θc + θb )

    = 184.78 + 78222.2 θc + 39111.1 θb

    M cd = MFCD + (2EI/L)(2θc + θd)

    = -286.03 + (2*1.76*10^5/9)( 2θc + θd )

    = -286.03 + 78222.2 θc + 39111.1 θd

    M dc = MFDC + (2EI/L)(2θd + θc )

    = 286.03 + (2*1.76*10^5/9)( 2θd + θc )

    = 286.03 + 78222.2 θd + 39111.1 θc

    M de = MFDE + (2EI/L)(2θd + θe)

    = -184.78 + (2*1.76*10^5/9)( 2θd + θe )

    = -184.78 + 78222.2 θd + 39111.1 θe

    M ed = MFED + (2EI/L)(2θe + θd )

    = 184.78 + (2*1.76*10^5/9)( 2θe + θd )

    = 184.78 + 78222.2 θe + 39111.1 θd

    Equilibrium equations:

    Mab = 0

    78222.2 θa + 39111.1 θb= 286.03

    Mba + Mbc = 0

    39111.1 θa + 1.56 * 10^5 θb +39111.1 θc = -101.25

    Mcb + Mcd = 0

    39111.1 θb + 1.56 * 10^5 θc +39111.1 θd = 101.25

    Mdc + Mde = 0

    39111.1 θc + 1.56 * 10^5 θd +39111.1 θe = -101.25

    Med = 0

    39111.1 θd + 78222.2 θe = -184.78

    Solving the unknowns,

    θa = 0.00474

    θb = -0.00216

    θc = 0.00130

    θd = -0.00044

    θe = -0.00214

    On Substituting,

    Mab = 0

    Mba = 302.46 kNm

    Mbc = -302.46 kNm

    Mcb = 201.99 kNm

    Mcd = -201.99 kNm

    Mdc = 302.46 kNm

    Mde = -302.46 kNm

    Med = 0

    Analyzing individual members,

    AB:

    ∑Ma = 0

    -9Rb1 + 302.46+(42.375*9*4.5)=0

    Rb1 = 224.3 kN

    Ra = 157.08 kN

    BC:

    ∑Mc = 0

    9Rb2 + 201.99-302.46-(27.375*9*4.5)=0

    Rb2 = 134.35 kN

    Rc1 = 112.02 kN

    CD:

    ∑Md = 0

    9Rc2 –(42.375*9*4.5)-201.99-302.46=0

    Rc2=179.52 kN

    Rd1 = 201.85 kN

    DE:

    ∑Me = 0

    9Rd2 –(27.375*9*4.5)-302.46=0

    Rd2 = 156.79 kN

    Re = 89.58 kN

    To get max positive and negative moment in span BC (as well as DE), BC and DE have to be loaded with LL

    Solving by slope deflection method,

    Fixed End Moments:

    MFAB = -(42.375*81)/12 = -184.78 kNm

    MFBA = 184.78 kNm

    MFBC= -(27.375*81)/12= -286.03 kNm

    MFCB = 286.03 kNm

    MFCD = -184.78 kNm

    MFDC = 184.78 kNm

    MFDE = -286.03 kNm

    MFED = 286.03 kNm

    Unknowns : θa, θb, θc, θd, θe

    E = 10 GPa = 10 * 10^6 kPa

    = 1 *10^7 kPa

    I = (0.5*0.75^3)/12 = 0.0176 m4

    EI = 1.76*10^5 kNm2

    End Moments:

    Span AB :

    M ab = MFAB + (2EI/L)(2θa + θb)

    = -184.78 + (2*1.76*10^5/9)( 2θa + θb )

    = -184.78 + 78222.2 θa + 39111.1 θb

    M ba = MFBA + (2EI/L)(2θb + θa )

    = 184.78 + (2*1.76*10^5/9)( 2θb + θa )

    = 184.78 + 78222.2 θb + 39111.1 θa

    M bc = MFBC + (2EI/L)(2θb + θc)

    = -286.03 + (2*1.76*10^5/9)( 2θb + θc )

    = -286.03+ 78222.2 θb + 39111.1 θc

    M cb = MFCB + (2EI/L)(2θc + θb)

    = 286.03 + (2*1.76*10^5/9)( 2θc + θb )

    = 286.03+ 78222.2 θc + 39111.1 θb

    M cd = MFCD + (2EI/L)(2θc + θd)

    = -184.78 + (2*1.76*10^5/9)( 2θc + θd )

    = -184.78+ 78222.2 θc + 39111.1 θd

    M dc = MFDC + (2EI/L)(2θd + θc )

    = 184.78 + (2*1.76*10^5/9)( 2θd + θc )

    = 184.78+ 78222.2 θd + 39111.1 θc

    M de = MFDE + (2EI/L)(2θd + θe)

    = -286.03 + (2*1.76*10^5/9)( 2θd + θe )

    = -286.03+ 78222.2 θd + 39111.1 θe

    M ed = MFED + (2EI/L)(2θe + θd )

    = 286.03 + (2*1.76*10^5/9)( 2θe + θd )

    = 286.03+ 78222.2 θe + 39111.1 θd

    Equilibrium equations:

    Mab = 0

    78222.2 θa + 39111.1 θb= 184.78

    Mba + Mbc = 0

    39111.1 θa + 1.56 * 10^5 θb +39111.1 θc = 101.25

    Mcb + Mcd = 0

    39111.1 θb + 1.56 * 10^5 θc +39111.1 θd = -101.25

    Mdc + Mde = 0

    39111.1 θc + 1.56 * 10^5 θd +39111.1 θe = 101.25

    Med = 0

    39111.1 θd + 78222.2 θe = -286.03

    Solving the unknowns,

    θa = 0.00214

    θb = 0.00044

    θc = -0.00130

    θd = 0.00216

    θe = -0.00474

    On Substituting,

    Mab = 0

    Mba = 302.46 kNm

    Mbc = -302.46 kNm

    Mcb = 201.99 kNm

    Mcd = -201.99 kNm

    Mdc = 302.46 kNm

    Mde = -302.46 kNm

    Med = 0

    Analyzing individual members,

    AB:

    ∑Mb = 0

    9Ra + 302.46-(27.375*9*4.5)=0

    Rb1 = 156.79 kN

    Ra = 89.58 kN

    BC:

    ∑Mc = 0

    9Rb2 + 201.99-302.46-(42.375*9*4.5)=0

    Rb2 = 201.85 kN

    Rc1 = 179.52 kN

    CD:

    ∑Md = 0

    9Rc2 –(27.375*9*4.5)-201.99-302.46=0

    Rc2=112.02 kN

    Rd1 = 134.35 kN

    DE:

    ∑Me = 0

    9Rd2 –(42.375*9*4.5)-302.46=0

    Rd2 = 224.3 kN

    Re = 157.08 kN
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