Airport Pavement Design (Course Notes).pdf

AIRPORT PAVEMENT DESIGN COURSE NOTES

May 2001

AIRPORT PAVEMENT DESIGN: COURSE NOTES 1. Pavement design concepts 2. Copies of transparencies 3. Copies of additional information A. B. C. D. E. F. G. H.

Typical layout Aircraft characteristics FAA design curves and adjustments for flexible and rigid British procedure Typical concrete slab layout Typical pavement structures for South African airports References Internet references

AIRPORT PAVEMENT DESIGN:

CONTENTS • Types of facilities • Types of airports • Aircraft characteristics • Design loading • Specific concepts • Design procedures • Examples

TYPES OF FACILITIES • Runway • Taxiway • Apron • Typical layout

TYPES OF AIRPORTS •

•

•

International: BOEING 767 TO 747 CONCORDE AIRBUS 300 & 320 DC - 10, 11 Regional: BOEING 737 TO 707 AIRBUS BA 146 DASH 7 F27, F28 Local: CESSNA DC - 3 BEECHCRAFT PIPER

AIRCRAFT CHARACTERISTICS TYPE

TOTAL LOAD

NO OF WHEELS

(kN) kN)

LOAD/WHEEL

PRESSURE

(kN) kN)

(MPa) MPa)

ACN / @ 10 F

CONCORDE

1815

8 - Dual tandem

218

1.26

72

B767 - 300

1 566

8 - Dual tandem

186

1.21

46

B747 - 400

3 796

16 - Dual tandem

223

1.38

45

V737 - 300

603

4 - Dual

138

1.14

31

934

4 - Dual

215

1.15

46

A300 - C4

1 629

8 - Dual tandem

189

1.24

51

A310 - 300

1 510

8 - Dual tandem

178

1.40

46

F27 Mk 400

194

4 - Dual

46

0.54

10

BAe146 - 200

400

4 - Dual

94

1.14

21

DASH 7

195

4 - Dual

46

0.74

6

B727 - 200 Advanced

DESIGN LOADING • Wheel load • Tyre pressure • Wander: • runway • taxiway

• Forces: • vertical • horizontal

• Example

SPECIFIC CONCEPTS •

Load classification number (LCN)

– – – •

•

Based on plate loading Calculated from Benkelman Beam /FWD For flexible or rigid

Aircraft classification number (ACN) and Pavement classification number (PCN)

–

Include: pavement type subgrade strength tyre pressure method of calculation

– –

Used since 1983 Single wheel load (kg/500) with same performance as group

Equivalent single wheel load (ESWL)

PCN •

DESCRIPTION

– –

PCN number Type of pavement R = rigid F = flexible

–

Pavement subgrade category A = High (CBR = 15) B = Medium (CBR = 10) C = Low (CBR = 6) D = Ultra low (CBR = 3)

PCN •

Maximum tyre pressure W = high (no limit) X = medium (< 1 500 kPa) Z = very low (< 500 kPa)

–

Evaluation method T = technical U = experience

PCN (CONT) – Example: 30/F/C/W/T

•

Calculation

–

Rigid Max Flexural stress = 2.75 Mpa Ec = 27.6 Gpa Poisson = 0.15 p = 1.25 Mpa Westergaard

–

Flexible: 10 000 repetitions p = 1.25 Mpa CBR or Boussinesq

DESIGN PROCEDURES •

ICAO

– Canadian – French – UK – FAA (USA) • • •

British FAA US CORPS

– CBR •

Asphalt Institute

DESIGN PROCEDURES (CONT) • PCA – Graphs – AIRPAV (Westergaard) • Mechanistic • South African

FAA METHOD • • • • • •

Design aircraft - largest thickness

•

Graphs (departures, gross mass, CBR)

Convert all aircraft to design Adjust annual departures Subgrade - CBR, k Critical on non-critical areas Wide bodies (> 45 500 kg): stabilise base and subbase

– Total thickness – Base course thickness

FAA METHOD (cont) • Flexible – – –

Subbase: CBR > 35, any type Base: CBR > 100, any type Surfacing: 100 mm AC

• Rigid – Wastergaard, edge loading – Subbase, any type – Panel size

BRITISH METHOD •

Design ACN: highest ACN mixed traffic

• •

Design life:

20 - 30 years

Frequency:

low - 10 000 over life medium - 10 000 high- 250 000

• •

Traffic patterns Coverages and Pass - to - Coverage ratio

BRITISH METHOD (CONT)

• •

Design curves (ACN, CBR, Traffic, PQC) Flexible

– Surfacing: 100 mm or 0.33 x DLC – Base: bound (DLC, AC), stabilised, granular (CBR > 30%) – Subbase: granular (CBR > 30%) •

Rigid

– Failure: 50% cracking – Subbase: DLC, stabilised or granular – Temperature warping (+ 10%) – Joints/slab size (type, aggregate)

EXAMPLES

EXAMPLE •Aircraft:

LAYER AC Surfacing Base Subbase Total

B747 - 200 F (380 000 kg) CBR = 10 ACN = 58 100 000 total rep 4 000 rep per year

BRITISH

FAA

SA 1

SA 2

100

100

75

75

500 BBM

250 Stab

100 G

200 WM

-

175 Stab

450 C

300 G

600

525

625

575