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

  1. 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





  1. 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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