Improved Surface Drainage of Pavements Final Report (1998) / Chapter Skim
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Appendix D Model Evaluation
Appendix D Model Evaluation
Pages 203-214
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From page 203... ...
The calculations were conducted for the four pavement types: dense-graded asphalt concrete, plain Portland cement concrete, grooved Portland cement concrete, and open-graded porous asphalt concrete. The values for the rainfall intensity, i, pavement slope, S
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From page 204... ...
Values of water film thickness versus flow paw length for the four pavement types are shown In figures D-1 through Dot. The figures show how the water film thickness varies for each of the variables when ache others are held at their extreme values.
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From page 205... ...
-- RF] = 152.4 mm~h 10 15 20 Flow oath distance.
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From page 206... ...
30 Figure ~2. Values for water film thlc~ess versus flow path length for Portland cement Dot
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From page 207... ...
Values for water film thiclmess versus flow path length for open-graded asphalt concrete pavement (no internal flow)
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From page 208... ...
Values for water film thickness versus flow path length for ppen-g~aded asphalt concrete pavement (internal rioter)
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From page 209... ...
The water film thickness is predicted in PAVDRN using the following relationship: (D-~)
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From page 210... ...
and the values and coefficients are In English units. The sensitivity analyses were conducted using procedures outlined earlier.
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From page 211... ...
SENSITIVITY OF THE: MODEL TO VARIATIONS IN N The partial derivative of the kinematic wave equation witch respect to n is: By 5.677 qO 6 = (D-3) On n04 S03 Using n 0.01, q 0.00000667 ft2/s, (0.00223m2/hr)
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From page 212... ...
SENSITIVITY OF THE MODEL TO VARIATIONS IN Q The partial derivative of the kinematic wave equation with respect to q is: BY = en 5.677 n06 q04 S03 Using n-0.05, q-0.0000694 ft2/s, (0.0232 huh)
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From page 213... ...
SENSITIVITY OF THE: MODEL TO VARIATIONS IN S The partial derivative of the ~nematic wave equation with respect to S is: ~Y _ ~ _ ~S -2~838 (n q)
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From page 214... ...
At high rainfall rates and tong drainage path lengths, the quantity of the flow has the largest effect on the depth. For the lowest values of the change in y, the order is: n > q > S This shows that at low flows, the resistance of the pavement, which is characterized by the Manning roughness coefficient, is the most dominant factor affecting the depth of flow D-12 .
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