AIRCRAFT PAVEMENTS. DESIGN and Construction. Rodway.pdf · AIRCRAFT PAVEMENTS. DESIGN and...
Transcript of AIRCRAFT PAVEMENTS. DESIGN and Construction. Rodway.pdf · AIRCRAFT PAVEMENTS. DESIGN and...
AIRCRAFT PAVEMENTS. DESIGN and Construction.
Bruce Rodway
Australian Society for Concrete PavementsForum for Airports and Ports. 22nd June 2009
Damage to Jet Engines and Propellers
• The worst concrete pavement is one that releases concrete fragments from its joint edges throughout its life. These loose fragments can be released without warning. They can damage propellers and can be sucked into jet engines, and at worst can cause engine failure in flight.
B747 engine damage
KSAP Eastern Apron, 30 years old. Cork joints. Very few spalls.
Qantas freight apron, Sydney Airport
Mobile Accelerated Loading Facility (ALF) testing at Beerburrum, Queensland
ALF
US FULL-SCALE TESTS on HIGHWAY PAVEMENTS
Airbus A380-562 tonnes
A380 (27 tonnes per wheel)
Antonov 225: 600 tonnes, 28 wheels
6802-Highway truck
95021265C17 transport
1,65030218B52 bomber
1,4001978Boeing B737
1,55028217B787 Dreamliner
1,57030366Airbus A340-600
1,52027352Boeing B777-300 ER
1,40024400Boeing B747
1,34027562Airbus A380
1,00020600Antonov 225
Tyre Pressure (kPa)
Wheel Load(tonnes)
Weight (tonnes)
Aircraft
Excavation for aircraft test pavements, US Corps of Engineers, Vicksburg Mississippi, 1966.
C5A US Military Transport. 350 tonnes
C5A-Simulating Test Roller
Test Roller Guidelines
Failure under B747 Roller
Corps of Enginees, Rigid pavement load test.
Corps of Engineers. Rigid pavement load test.
US Corps of Engineers CBR Curve
0
0.001
0.002
0.003
0.004
0.005
0.006
0 2000 4000 6000 8000
Coverages
Vertical Strain
HALFWAY
275 m
18 m
US Accelerated Loading Facility
FAA Test Facility. 8-wheel loading
FAA Test Facility-Flexible pavement deformation
Concrete test area-B777 static load test.
Concrete Warping Cracks
High-Strength Subgrade Rigid Test Item
Lane 2
Lane 3
Lane 1
Slab 1 Slab 2 Slab 3 Slab 4 Slab 5
NORTH
100 Feet
60 Feet
Feb 14>Feb 14
<Feb 14
A380 Airbus pavement load test
Patched Continuously Reinforced Concrete Taxiway, Chicago Airport
Changi multi-patched taxiway
Asphalt rutting, Dubai
Installation of heating coils at US test facility.
Transverse sawn contraction joint (“dummy” joint).
Cages for transverse dowels, Denver
COATING DOWELS
Crooked dowels
Cracks due to misaligned dowels
Edge slump correction of slipformed concrete,530mm thick at Chicago Airport
Slipformed concrete. Deviated edge to be removed by sawing
Edge Slump, 530mm slipformed concrete
Slipformer ‘straddling’ forms. Brisbane Airport’s International Apron, 400mm thick
Slipformer placing 500mm thick concrete between forms at New Delhi airport
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Austroads design vs. Heavy Aircraft design Methods
Subgradestrain
Austroads Heavy Aircraft Ratio
0.0005 618 x106 1.5 x 106 410:1
0.001 4.4 x 106 15,000 290:1
0.002 30,000 160 190:1
Predicted Load Repetitions to Failure for identical subgrade strains
Questions?
0.001
0.01
1 10 100 1000 10000
N
εεεεN
k b= ��
��ε
�A damage model relates pavement life to a computable indicator of damage such as subgrade compressive strain, etc.
� The models are of the form:
Damage models
Nk b
= ����ε
strainrepetitions to failure
Effect of wheel load on pavement rutting for equal subgradestrains
0
500
10000 0.005 0.01 0.015 0.02 0.025
Vertical Strain
Depth (mm)
20 tonne
4 tonne
4 tonne20 tonne
Top of subgrade
Effect of wheel load on load pulse shape at subgrade
level
-0.005
0
0.005
0.01
0.015
0.02
0.025
0 200 400 600 800 1000 1200
Distance (mm)
Ver
tica
l Str
ain
20 tonne
4 tonne
4 tonne
20 tonne
Airfield concrete-Differences from Road and Building concrete.
• Lower maximum slump of 50mm• Larger maximum stone size of 38mm (1.5 inches)• No steel reinforcement• River gravel not used• Flyash not used• Can’ t be pumped• Thicker than roads (400mm vs 250mm)• Slipforming not used on airfields in Australia• Strength measured by beams not cylinders• Must be water cured for 24 hours, not membrane
12 June 1994