Airport/Airfield Flexible pavement design: These sildes contain manual and computer design procedure of flexible pavement design of runway.

1. Flexible
Pavement
Design
FOYSOL MAHMUD
Department of Civil Engineering
Leading University, Sylhet

2. NAME OR LOGO
Design Flowchart
According to Federal Aviation Administration
(FAA) method.
2
Taking an aircraft as design aircraft.
Convert the wheel loads of other
aircraft to the design aircraft
Finding equivalent annual departures by
design aircraft.
Finding Total equivalent annual
departures by design aircraft.
Calculating the thickness from FLEXIBLE
PAVEMENT DESIGN NOMOGRAMS
Transportation Engineering III

3. NAME OR LOGOTransportation Engineering III 3
Aircraft Gear Type
Average Annual
Departures
Maximum Takeoff Weight
lbs. (kg)
727-100 dual 3,760 160,000
727-200 dual 9,080 190,500
707-320B dual tandem 3,050 327,000
DC-g-30 dual 5,800 108,000
cv-880 dual tandem 400 184,500
737-200 dual 2,650 115,500
L-101 l-100 dual tandem 1,710 450,000
747-100 double dual 85 700,000
Sample
Design
of Flexible
Pavement
An airport flexible pavement is to be designed for the following forecast aircraft.
Subgrade CBR = 6%
Sub-base CBR = 20%
Design Life = 20 years

4. NAME OR LOGOTransportation Engineering III 4
Conversion of Aircraft to Equivalent
Annual Departures of the Design Aircraft
Taking 727-200 as the design Aircraft
Aircraft Gear Type
Maximum
Takeoff Weight
(lbs)
Wheel Load
(lbs)
W2 W1
727-100 dual 160,000 38,000 45,240
727-200 dual 190,500 45,240 45,240
707-320B dual tandem 327,000 38,830 45,240
DC-g-30 dual 108,000 25,650 45,240
cv-880 dual tandem 184,500 21,910 45,240
737-200 dual 115,500 27,430 45,240
L-101 l-100 dual tandem 450,000 35,625 45,240
747-100 double dual 700,000 35,625 45,240
(190500*0.95)/4
**Front Wheel take 5% load
**Landing gears take 95% load
**Dual Wheel (4 wheel)
Design aircraft wheel load
5% 95%

5. NAME OR LOGOTransportation Engineering III 5
Conversion of Aircraft to Equivalent
Annual Departures of the Design Aircraft
Aircraft Gear Type
Average Annual
Departures
Conversion
Factor
Equivalent dual
Gear Departure
R Fi R2
727-100 dual 3,760 1 3760
727-200 dual 9,080 1 9080
707-320B dual tandem 3,050 1.7 5185
DC-g-30 dual 5,800 1 5800
cv-880 dual tandem 400 1.7 680
737-200 dual 2,650 1 2650
L-101 l-100 dual tandem 1,710 1.7 2907
747-100 double dual 85 1.7 145
R*Fi = R2
3050*1.7=5185

6. NAME OR LOGOTransportation Engineering III 6
Final
Conversion
To equivalent annual departures
by the design aircraft.
R1 – equivalent annual departures of the design aircraft
R2 – annual departures expressed in design aircraft
landing gear configuration
W1 – wheel load of the design aircraft
W2 – wheel load of the aircraft being converted
W2 W1 R2 R1
38,000 45,240 3760 1891
45,240 45,240 9080 9080
38,830 45,240 5185 2764
25,650 45,240 5800 682
21,910 45,240 680 94
27,430 45,240 2650 463
35,625 45,240 2907 1184
35,625 45,240 145 83
Total= 16241
logR1=log(3760)
38000
45240
Final design: 16,241 annual departures of a dual wheel aircraft weighing 190,500lbs

7. NAME OR LOGOTransportation Engineering III 7
Calculating the thickness from
FLEXIBLE PAVEMENT DESIGN NOMOGRAMS
For CVR 6% thickness above subgrade = 36”, for 20% thickness
above sub-base = 17”
Surface = 4” , Base = 13”, Subbase = 19”
4”
13”
19”

8. NAME OR LOGOTransportation Engineering III 8
Computer
Design
Designed with
FAARFIELD v1.42
GUI of FAARFIELD
Result provided by
FAARFIELD

9. NAME OR LOGO
Question?
Feel free to ask any question
9Transportation Engineering III

10. Thank
You
For paying attention