Given the following air traffic demand Aircraft Wheel Configuration Load per Wheel (W) Arrivals Departures B-727-200 (dual) B-757-200 (dual) B-747-100 (dual-tandem) 60,000 lb 55,000 lb 88,000 lb 1600 1600 7000 7000 1400 1400 a) Determine the required thickness of each layer of a flexible pavement for a runway to accommodate the above air traffic demand. grade, 18 b) If the modulus of abgrade reaction is 50 pai/inch, determine the required thickness of a rigid pavement (pee with flextural strength of 750 pai) for a runway to socommodate the above air traffic denand. AC 150/5320-6D CBR 3 4 5 6 7 8 910 15 20 30 40 50 B-747-100, SR, 200 B, C, F CONTACT AREA -245 SQ IN. DUAL SPACING TANDEM SPACING CBR 3 4 5 6 7 8 910 15 20 30 40 50 1 B-747-100, SR, 200 B, C, F CONTACT AREA DUAL SPACING TANDEM SPACING 245 SQ IN. 44 IN. 58 IN. GROSS AIRCRAFT WEIGHT, LB $850,000 700,000 800,000 600,000 500,000 400,000 $300,000 1 in. 25.4 mm 1 lb. 0.454 kg ANNUAL DEPARTURES 6,0001 15,000 25,000 1,200 3,000 THICKNESS HOT MIX ASPHALT SURFACES 5-IN. CRITICAL AREAS 4-IN. NONCRITICAL AREAS 3 4 5 6 7 8 910 0793 15 20 30 40 50 THICKNESS, IN. FIGURE 3-7 FLEXIBLE PAVEMENT DESIGN CURVES, B-747-100,SR, 200 B, C, F 900- 850- 800- 750- CONCRETE FLEXURAL STRENGTH, psi 700- 650- 600- 550- 500- 07938 B-747-100, SR, 200 B, C, F CONTACT AREA DUAL SPACING TANDEM SPACING 245 SQ. IN. -44 IN 58 IN 850,000 000,000 000'000 400,000 300.000 NOTE: ANNUAL DEPARTURES 1,200 6,000 25,000 3,000 15,000 22 -26 27 -23-24 -25 -20 -21 -22 23 24 25 -20 21 22 23 24 19 20 21-22 23 18 19 20 21 22 -21 17 18 19 20 20 16 17 18 19 19 -17-18 15 16 1017 18 1415 1516 13 14 1415 12 13 1314 -12 -11 -12 13 11 -12 10 11 12 10 -11 10 11 9 10 10 9 8 1 inch 25.4 mm 1 psi 1 pci 0.0069 MN/ 0.272 MN/m 1 lb-0.454 kg FIGURE 3-22. RIGID PAVEMENT DESIGN CURVES, B-747-100, SR, 200 B, C, F SLAB THICKNESS, in