ftc slab dsn
DESCRIPTION
two way slab designTRANSCRIPT
Design of two-way slab
Panel No = S1 Input data: ACI Moment Coefficients
Case No = 2
la = 15 ft m = 1.00
lb = 15 ft = 0.045
f'c = 3 ksi = 0.045
fy = 60 ksi = 0.018
DL add = 0.06 = 0.018
LL = 0.03 = 0.027
h, cal = 4 in = 0.027
h, used = 6 in Wa = 0.500
Wb = 0.500
Loads Calculation: Moments Calculation:
DL wu = 0.162 Ma(-ve) = 25.52 k-in
LL wu = 0.048 Mb(-ve) = 25.52 k-in
TL wu = 0.21 Ma(+ve) = 11.37 k-in
Mb(+ve) = 11.37 k-in
Steel Calculation:
= 5 in Moments #4(in c/c)#3(in c/c)
= 4.75 in Ma(-ve) 0.13 12 10.2
= 0.85 Mb(-ve) 0.13 12 10.2
= 0.914 Ma(+ve) 0.13 12 10.2
= 0.13 Mb(+ve) 0.13 12 10.2
= 12
Load Transfer:
Load Transfer To Longer Beam = 0.788 k/ft
Load Transfer To Shorter Beam = 0.788 k/ft
Caneg
Cbneg
Cadl
k/ft2 Cbdl
k/ft2 Call
Cbll
k/ft2
k/ft2
k/ft2
da
Asreq
db
Asmax in2
Asmin in2
Smax
Design of two-way slab
Panel No = S1 Input data: ACI Moment Coefficients
Case No = 8
la = 15 ft m = 1.00
lb = 15 ft = 0.033
f'c = 3 ksi = 0.061
fy = 60 ksi = 0.020
DL add = 0.06 = 0.023
LL = 0.03 = 0.028
h, cal = 4 in = 0.030
h, used = 6 in Wa = 0.330
Wb = 0.670
Loads Calculation: Moments Calculation:
DL wu = 0.162 Ma(-ve) = 18.71 k-in
LL wu = 0.048 Mb(-ve) = 34.59 k-in
TL wu = 0.21 Ma(+ve) = 12.38 k-in
Mb(+ve) = 13.95 k-in
Steel Calculation:
= 5 in Moments #4(in c/c)#3(in c/c)
= 4.75 in Ma(-ve) 0.13 12 10.2
= 0.85 Mb(-ve) 0.139 12 9.5
= 0.914 Ma(+ve) 0.13 12 10.2
= 0.13 Mb(+ve) 0.13 12 10.2
= 12
Load Transfer:
Load Transfer To Longer Beam = 0.52 k/ft
Load Transfer To Shorter Beam = 1.055 k/ft
Caneg
Cbneg
Cadl
k/ft2 Cbdl
k/ft2 Call
Cbll
k/ft2
k/ft2
k/ft2
da
Asreq
db
Asmax in2
Asmin in2
Smax
T-Beam DesignMaterial
Concrete Compressive Strength fc' 3000 psi
Rebar Yield Strength fy 40000 psi
Unit Weight of Concrete wc 150 pcf
Dimensionsc/c distance b/w the beams 10 ftc/c span 30.75 ftClear Span(Exterior) Ln1 29.25 ftClear Span(Interior) Ln2 29.25 ftSupport Width 18 in
Beam Depth h 24 inclear cover to rebar centre c.c 3 ineffective depth d 21 inBeam Width bw 12 inSlab Thickness hf 6 in
Effective Flange Width beff 92.3 in
Support Length L 30.75 ft
Loads Calculations
Service Dead Load from Slab SDL 1.25 k/ftBeam Self Weigth Wself 0.225 k/ft
Total Dead Load DL 1.475 k/ft
Live Load from Slab LL 0.4 k/ft
Total Service Load Ws 1.875 k/ft
Total Factored Load Wu 2.41 k/ft
Bending Moment CalculationEquivalent Compression Depth
Trial-1 a 6.0 in
As 3.5 in^2
Trial-2 a 0.6 in
As 3.0 in^2
Trial-3 a 0.5 inAs 3.0 in^2
Trial-4 a 0.5 in
Shear Reinforcmenth 36 inc.c 1.5 ind 34.5 inbw 12 infc' 4000 ksify 40000 ksiVu 135 kipsphi 0.75phi Vc 39.27548854 kips
SpacingUsing #3, 2-Legged Stirrup
Bar # 3No. of Legs 2Av 0.222222222 in^2Design Spacing 2.402728376 in
Max Spacing
14.81
14.8117.25
24.0015.62
Provide # 3
Development Length of Beam Bar in ColumnDia Bar 0.75 inld 7.297563831 in
hmin(in)Case1 Simply Supported L/16 18
Case2 One End Continous L/18.5 16
Case3 Both Ends Continous L/21 14
Case4 Cantilever L/8 37
3.012133879
0
85.913128.87
ACI Moments(kip-ft) for:Discontinous End Unrestrained 0 187.4
Spandrel 85.9 147.3
Column 128.9 147.3
Compare with hmin
Ln1
Ln1
inches
@ 2.40 c/c
206.2 187.4 128.9 187.4 187.4
Ln2
Ln2
Slab Reinforcement Detail(6in Thick)1st Floor
M1 #4 @ 9in c/c MT1 #4 @ 6in c/cM2 #4 @ 9in c/c MT2 #4 @ 6in c/c
2nd FloorM1 #3 @ 9in c/c MT1 #3 @ 6in c/cM2 #3 @ 9in c/c MT2 #3 @ 6in c/c
RoofM1 #3 @ 9in c/c MT1 #3 @ 9in c/cM2 #3 @ 9in c/c MT2 #3 @ 9in c/c
Footing Reinforcement Detail(15in Thick)
Slab on GradeM1 #4 @ 9in c/c MT1 #4 @ 6in c/cM2 #4 @ 9in c/c MT2 #4 @ 6in c/c
Grade Beam
Square Footing InputsAlpha 20Colum C1 13 in
C2 13 inDL on Column kipsLL on Column kipsSDL 210 kipsWu 230 kipsDepth of footing Z 5 ftFloor Thickness 6 in 150 pcfFill 39 in 120 pcfFloor Loading 275.5 psfBearing Capacity 4408 psfAssume Thickness of footing equal to 1 to 2times column dimension
13 inSay 15 in 150 pcfd 11 in
Materialfc' 3500 psify 60000 psi
Allowable Net Pressureqn 3.48 ksf
Area RequiredA 60.34483 ft^2
Width of FootingB 7.768193 ftSay 6 ftA 36 ft^2
Factored Net Soil Pressureqf 6.388889 ksf
Check the thickness for punching shear
Punching AreaAp 4 ft^2
Critical Perimeterbo 96 in
Punching Shear DemandVup 204.4444 kips
OK if phi Vc > Vu otherwise increase thicknessPunching Shear Capacityphi Vc 212.4109 kips
Check the thickness for one way shear
Beam Shear Width
18.5 inShear Demand
Vu 59.09722 kips
OK if phi Vc > Vu otherwise increase thicknessShear Capacityphi Vc 79.6541 kips
Design of Reinforcment
Moment Demand
Mu 115.8319 kip-ft
Area of Steel Requireda 3 inAs 2.709518 in^2a 0.758969 inAs 2.423651 in^2a 0.678894 inAs 2.414548 in^2a 0.676344 inAs 2.414259 in^2 Asmin 1.944 in^2
Check a/d with table A-4 for phiphi 0.9
Bar # Bar Area Spacing of Bars Try6 0.44 2.2 7 # 6 @ 38 0.79 3.9 4 # 8 @ 59 1.00 5.0 3 # 9 @ 611 1.49 7.4 2 # 11 @ 9
Allowable Bearing on Footing
174.0375 kips
Allowable Bearing on the Base of Column
351.943 kips Should be great than 230 kips
Column Interior Edge CornerAlpha 40 30 20
Beta c Bc 1
OK if phi Vc > Vu otherwise increase thickness
OK if phi Vc > Vu otherwise increase thickness
As phi Mn
in c/c 3.1 149 kip-ft
> 116 kip-ftin c/c 3.2 152 kip-ft
in c/c 3.0 144 kip-ft
in c/c 3.0 143 kip-ft
otherwise provide dowels