Mu = 87.9Vu = 50Yr = 0.4C1 = 24C2= 24d = 6.75a = 27.375b = 30.75c = 8.764803Ac = 577.125J/c = 5634.237

Vu = Vu/Ac +Yr x Mn / ( J/c ) = 161.5214

Mu = 87.9Vu = 50Yr = 0.4C1 = 18C2= 24d = 6.75a = 21.375b = 30.75c = 6.216199c' = a - c = 15.1588Ac = 496.125J/c' =(J/c)(c/c') = 2310.443

Vu = Vu/Ac -Yr x Mn / ( J/c' ) = -81.8333

FLAT SLAB

DATAL1 = 20.5 ft.L2 = 16 ft.C1 = 18 in.C2 = 18 in.Ln = 19 ft.fc' = 3,000 psify = 50,000 psi

DESIGNPreliminary design of slab thickness "h" Live Load 60 psfa) Control of deflection Finishes 91 psf

h = Ln / 33 = 7.6 in. Super Dead 20 psfThis is larger than the 5 in. minimum specified for slabs without drop panels.Therefore use a slab thickness

h = 9 in.Average effective depth = d = h - 0.75 - 1/2" bar = 7.75 in.

b) Shear strength of slabFactored dead load = wd = (h*12.5+FF+SD)*1.4 = 312.9 psfFactored live load = wl = LL*1.7 = 102 psf

414.9 psf

Investigation for wide beam action on 12" wide strip at "d" distance from face of support L1/2 - C1/2 - d = 8.854167 ft.

Vu = 3.67 kipVc = 2* fc' *bw*d = 10.19 kip

Æ Vc =0.85*Vc= 8.66 kip3.67 is less than 8.66

OKShear strength in two way action at d/2 distance around a support

bo = 103 in.

Vu = 134.18 kipVc = 4* fc' *bo*d = 174.89 kip

Æ Vc =0.85*Vc= 148.65 kip134.18 is less than 148.65

OK

Total factored load = wu =

4*(C1+d/2+d/2) =

wu*[L1*L2 - ((C1+d/2+d/2)/12)2] =

Factored moments in slabTotal factored moment per span

Mo = 299.6 k-ft.

Distribution of the total factored moment Mo per span into negative and positive moments

TOTAL MOMENT COLUMN STRIP MIDDLE STRIP ( k-ft.) MOMENT ( k-ft ) MOMENT ( k-ft )

End span:Exterior Negative 0.26*Mo= 77.9 0.26*Mo= 77.9 0Positive 0.52*Mo= 155.8 0.31*Mo= 92.9 0.21*Mo= 62.9Interior Negative 0.70*Mo= 209.7 0.53*Mo= 158.8 0.17*Mo= 50.9

Interior span:Positive 0.35*Mo= 104.8 0.21*Mo= 62.9 0.14*Mo= 41.9Negative 0.65*Mo= 194.7 0.49*Mo= 146.8 0.16*Mo= 47.9

Spacing of Spacing ofSPAN LOCATION Mu b d As=Mu/3.9d As (min.)) #12 bar #16 bar

provided provided

END SPAN

COLUMN Exterior Negative 77.9 120 6.75 2.959 1.944 10"STRIP Positive 92.9 120 6.75 3.528 1.944 8"

Interior Negative 158.8 120 6.75 6.031 1.944 8"

MIDDLE Exterior Negative 0 120 6.75 0.000 1.944 10"STRIP Positive 62.9 120 6.75 2.390 1.944 10"

Interior Negative 50.9 120 6.75 1.934 1.944 10"

INTERIOR SPAN

COLUMN Interior Negative 146.8 120 6.75 5.576 1.944 8"STRIP Positive 62.9 120 6.75 2.390 1.944 10"

.MIDDLE Interior Negative 47.9 120 6.75 1.821 1.944 10"STRIP Positive 41.9 120 6.75 1.593 1.944 10"

wu*L2*Ln2 / 8 =

Transfer of gravity load shear and moment at exterior column.a) Factored shear force transfer at exterior column:

Vu = wu*L1*L2/2 = 68.0436 kip

b) Unbalanced moment transfer at exterior column:

t 0.6*Mu = 46.73 k-ft.

unbalanced moment transfer section = t = C1+2(1.5*h) = 45 in.Above unbalanced moment must be transferred within the effective width of 45 in.

Add 2 # 16 bars additional over column.Check moment strength for 4 # 12 + 2 # 16 bars with in 45 in. slab width.

For 4 # 12 + 2 # 16 bars: As = 1.324w = As*fy/fc' *t*d = 0.063

From table 9-2 0.0879

Mn = 59.39 k-ft

Æ Mn = 0.9 x Mn = 53.45 k-ft > 46.73 k-ft.

Safe

f x Mu =

in2.

Mn / fc'*b*d2 =

w*fc'*b*d2=

Spacing of