Road Pavements
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CONCRETE PAVEMENT CALCULATION GIVEN or KNOWN DATA Ground water surface Dw -1 m Soil unit Weight 1.6 Concrete unit Weight 2.4 Water unit Weight 1 Angle of Soil Friction φ 28.61 Concrete Thickness h 300 mm Concrete cover Thickness c 50 mm Reinforcement Grade 500 Mpa Concrete Grade f'c 30 Mpa Soil Properties CBR Value as per soil investigation 3.00 % CALCULATION A. K-Value - From Cohesion-Less Soil correlation 1600 16.02014 = 99.874286 K = 50 psi/in from table-11 AASTHO K = 13.55 kPa/mm K = 13550 kPa/m - From CBR Soil correlation CBR = 3 % K = 75 psi/in from fig.41 AASTHO K = 20.325 kPa/mm K = 20325 kPa/m K-average = 16.9375 kPa/mm = 16937.5 kPa/m B. Subbase modulus Sub-base layer will be CBR = 88942 kPa from fig.2.7 AASTHO Base Layer will be CBR 80% = 196500 kPa from fig.2.6 AASTHO Esb Average = 142721 kPa 20699.93 6.8947576 Dsb, Subbase Thickness = 300 mm = 11.811024 Inches Esb = 20699.93 Psi = 2456.5763 Psi Found, K∞ = 400 Pci from fig.3.3 AASTHO = 110720.43 kN/m3 276.801075269 γd T/m 3 γc T/m 3 γw T/m 3 o fy γd = kg/m 3 lb/ft 3 C. Composite modulus of subgrade reaction (K∞) MR, Soil Resilient Modulus
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Transcript of Road Pavements
CONCRETE PAVEMENT CALCULATION
GIVEN or KNOWN DATAGround water surface Dw -1 m
Soil unit Weight 1.6
Concrete unit Weight 2.4
Water unit Weight 1
Angle of Soil Friction φ 28.61Concrete Thickness h 300 mmConcrete cover Thickness c 50 mm
Reinforcement Grade 500 MpaConcrete Grade f'c 30 Mpa
Soil Properties
CBR Value as per soil investigation 3.00 %
CALCULATIONA. K-Value- From Cohesion-Less Soil correlation
1600 16.02014
= 99.874286K = 50 psi/in from table-11 AASTHOK = 13.55 kPa/mmK = 13550 kPa/m
- From CBR Soil correlationCBR = 3 %
K = 75 psi/in from fig.41 AASTHOK = 20.325 kPa/mmK = 20325 kPa/m
K-average = 16.9375 kPa/mm= 16937.5 kPa/m
B. Subbase modulusSub-base layer will be CBR 20% = 88942 kPa from fig.2.7 AASTHOBase Layer will be CBR 80% = 196500 kPa from fig.2.6 AASTHOEsb Average = 142721 kPa
20699.93 6.8947576
Dsb, Subbase Thickness = 300 mm= 11.811024 Inches
Esb = 20699.93 Psi
= 2456.5763 PsiFound, K∞ = 400 Pci from fig.3.3 AASTHO
= 110720.43 kN/m3276.801075269
γd T/m3
γc T/m3
γw T/m3
o
fy
γd = kg/m3
lb/ft3
C. Composite modulus of subgrade reaction (K∞)
MR, Soil Resilient Modulus
D. LoadingWheel Load Pressure = 150 kN/m2
Contact Area = 0.15 m2 22.5Maximum Wheel Load Pressure = 22.5 kN
= 4960.713 Pounds 0.00454Thickness = 300 mm 25.406504
= 11.808 Inches= 350 Psi from fig.3.9 AASTHO
E. Minimum Percentage of Longitudinal Reinforcement
Indirect tensile Strength of PC = 4.5 Mpa 0.0069018= 652 psi
= 67 ksi from Table 3.7 AASTHO
Temperature drop design = 50Concrete shrinkage at 28 days, Z = 0.0003 in/in from Table 2.9 AASTHO
P = 0.32 % from fig 3.12 AASTHO
F. Minimum Percentage of Longitudinal Reinforcement to satisfy Crack widthAllowable crack width = 0.04 inFound P = 0.32 % from Table 3.11 AASTHOThe minimum reinforcement for concreteslab/Rigid pavement = 0.32 %
= 1.4= 0.0028fy
0.0028
d' = 250 mmAs req = ρ.b.d
= 0.0028 x 1000 x 250= 700 mm2
Choosen Re-bar = 8 As' = 50.265482 mm2Space Need = 71 mm
Take D 8 - 150
300 mm Concrete Slab
100 mm SubBase coarse 50% CBR
compacted 95% Standard Proctor
Wheel Load Tensile Stress, σ
Wheel Load Tensile Stress, σs
0 F
minimum reinforcement ρ
Since ρ < ρ min, then use ρ min =
for punching shear, takes the critical loading that is located in rear side of the vehicle
f'c = 21t = 300 mm V = 22.5 kN
V = 23 kN
» 22500 N
0.75
30000 N
2200 mm
504043 N
Vc>Vn ?500
300
504043 N > 30000 N ….proceed to use
N/mm2
f =
Vn = V/f =
bo = 45o
Vc = 1/6 x √f'c x bo x d' =
