Aashto Equation for Flexible Pavement

ED UNIVERSITY OF ENGINEERING USAMA FAREED UE-027 B.E. URBAN U.E – S.E INTRODUCTION TO TRANSPORTATION TRANSPORTATION PLANNING PROF. DR. MIR SHABBAR ALI

AASHTO Equation:LOG10W18 = ZR SO + 9.36 [LOG10 (SN+1)] - 0.20 + LOG10 [ΔPSI/2.7] +2.32LOG10MR  -8.07 0.40 + [1094/ (SN+1) 5.19]

Where:W18 = 18-kips equivalent single axle load ZR  = Reliability ( z-statistic from the standard normal curve ) So = Overall standard deviation of traffic SN = Structural number  ΔPSI = Loss in serviceability from the time the pavement is new until it reaches its TSI MR  = Soil resilient modulus of the subgrade in lb/inch 2

W18=? Variables W18 = ZR = So = SN = ΔPSI = MR =

### -1.65 0.35 5 1.9 5000

Log10 W18

=

#NAME?

=

Q No.4.6 Given:

#NAME? -1.65 0.35 5 1.9 5000

ZR=?

So=? ΔPSI=? Values 5469244 5469224 5469224 #NAME? -1.65 -1.65 0.35 #NAME? 0.35 5 5 5 1.9 1.9 #NAME? 5000 5000 5000

MR=? 5469224 -1.65 0.35 5 1.9 #NAME?

ZRSO + 9.36 [LOG10 (SN+1)] - 0.20 + LOG10 [ΔPSI/2.7] +2.32LOG10MR -8.07 .40+[1094/(SN+1)^5.19 #NAME?

D1 = 4” D2 = 7” D3 = 10” Mr = 5000 lb/in2 Reliability = 90% Z = -1.282 So = 0.4 ∆PSI = 2.0 TSI = 2.5 m2 = .9 m3 = .8 From Table 4.6 a1 = .44 a2 = .14 a3 = .11

Solution:

Structure Number: Sn = a1D1m1 + a2D2m2 + a3D3m3 Sn =

3.52

a1

0.44 D1 0.14 D2 0.11 D3

a2 a3

W18=? Variables W18 = ZR = So = SN = ΔPSI = MR =

#NAME? -1.28 0.4 3.52 2 5000

Log10 W18

=

#NAME?

=

4 m1 7 m2 10 m3 ZR=?

So=? Values

ΔPSI=?

MR=?

#NAME? #NAME? #NAME? #NAME?

ZRSO + 9.36 [LOG10 (SN+1)] - 0.20 + LOG10 [ΔPSI/2.7] +2.32LOG10MR -8.07 .40+[1094/(SN+1)^5.19 #NAME?

W18 = 1099593

For 25 kip Single Axle Load. W25 = (W18*18/25)

1 0.9 0.8

W25 =

###

Results Sn = 3.52 W18 = 1099593 W25 = .7918x10^6 ESAL

Q No. 4.7

For ESAL CALCULATION: Axle Type o. of Axl Load (kip) Single 300 10 Single 120 18 Single 100 23 Tandem 100 32 Single 30 32 Tridem 100 40

T.F 0.12 1 2.63 0.84 10.5 0.55

ESAL 35.4 120 263 84.3 315 55.4

∑ESAL=

0 873.1

Given: D1 = 4” D2 = 6” D3 = 7” Reliability = 85% Z = -1.036 So = 0.3 ∆PSI = 4.7-2.5 = 2.2 m2 = 1 m3 = 1 From Table 4.6 a1 = .35 a2 = .2 a3 = .11

Structure Number: Sn = a1D1m1 + a2D2m2 + a3D3m3 Sn =

3.37

a1

0.35 D1

4 m1

1

a2 a3

0.2 D2 0.11 D3

6 m2 7 m3

1 1

 Yearly Traffic = Daily Traffic x 365 Y.T.=

### Value 1290.94

Daily Traffic =

Design ESAL = Design Life x Yearly Traffic Design ESAL =

4711931 Values

Design Life= Yearly Traffic=

10 471193.1 W18=?

Variables W18 = ZR = So = SN = ΔPSI = MR =

ZR=?

So=? Values

ΔPSI=?

#NAME? #NAME? #NAME? #NAME?

Log10 W18

=

#NAME?

=

Result: Mr=7298.793 lb/in2

MR=? 4711931 -1.04 0.3 3.37 2.2 #NAME?

ZRSO + 9.36 [LOG10 (SN+1)] - 0.20 + LOG10 [ΔPSI/2.7] +2.32LOG10MR -8.07 .40+[1094/(SN+1)^5.19 #NAME?

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