CE-461 Runway Geometric Design
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Transcript of CE-461 Runway Geometric Design
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Transportation Engineering - II
Airport Classification&
Runway Geometric Design
Dr. Indrajit Ghosh
Assistant Professor
Department of Civil Engineering
Indian Institute of Technology Roorkee
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Lecture Outline
Airport Classification ICAO
FAA
Runway Geometric Runway length
Runway Width
Transverse Grade Longitudinal Grade
Rate of change of Longitudinal Grade
Sight Distance Requirements
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Airport Classification
In order to provide a guideline to airport
designers for a reasonable amount of
uniformity in airport landing facilities
Design criteria have been prepared by ICAO
and FAA through airport classification
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Airport Classification
ICAO classification
Employ an aerodrome reference code
consisting of two elements
Element 1: a number based on effective runwaylength
Element 2: a letter based on aircraft wing span and
outer main gear wheel span
Code number or letter within an element
selected for design purposes is related to
critical airplane characteristics
For which facility is provided
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ICAO Reference Code
Code element 1 Code element 2
Code no. Aeroplane
reference field
length (m)
Code letter Wing span
(m)
Outer main
gear wheel
span (m)*
1
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Airport Classification
An airport designed to accommodate a
Boeing 767-200 with an outer main gear
wheel span of 10.44 m width, a wingspan of
48 m, at a maximum take off weight of 144tonne, requiring a runway length of about
1830 m at sea level on a standard day will be
classified as _____________
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Airport Classification
FAA Airport Reference Code
Coding system used to relate the airport design
criteria to the operational and physical
characteristics of the aircraft intended to operateat the airport
Based up on
Aircraft approach category
Approach speed
Airplane design group to which the aircraft is assigned
Based on wingspan and tail height
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FAA Reference Code
Aircraft approach
category
Aircraft approach
speed (kn)
Airport category
A
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Airport Classification
FAA airport approach category classification
Two broad airport classes
Utility airports
Designed, constructed and maintained to
accommodate aircraft from approach categories A & B
Serve small aircraft with maximum take-off weight of
12500 lbs (up to 5000 kg)
Transport airports
Can accommodate large aircraft with maximum take off
weight in excess of 12500 lbs (above 5000 kg)
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FAA Reference Code
FAA Airplane Design Groups for Geometric Design of Airports
Airplane design
groups
Aircraft wingspan (m) Tail height (m)
I < 14.9
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Runway Geometric
ICAO gives various geometric standards for
airport design
Most of its member provide international air
service
To have uniformity in landing facility at
airports located in different countries
Desirable to follow common design standardsas recommended by ICAO
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Runway Geometric
Following items are considered
Runway length
Runway width
Width and length of safety area
Transverse gradient
Longitudinal and effective gradient Rate of change of longitudinal gradient
Sight distance
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Runway Geometric
Runway Length
One of the most significant factor in deciding size
and cost of airport
Length should be sufficient for take off andlanding of CRITICAL AIRCRAFT DESIRING
SERVICE AT AIRPORT
Basic runway length
Modified for elevation, temperature and gradient
correction
Airports are classified according to reference
codes (ICAO) based on aeroplane reference field
lengths
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Runway Geometric
Runway Width
Depends upon type of airport and largest aircraft
in operation
Studies have shown aircraft traffic is moreconcentrated in central part of runway
Lateral distribution of traffic on runway can be
represented by a normal distribution
% wheel load applications vs. distance from centerline ofrunway
Impact of factors like night operation, crosswind,
wet pavements is not significant on distribution of
aircraft traffic on runway
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Runway Geometric
Runway Width
In case of large airport serving large aircrafts, the
central 30 m width of the runway pavement is
observed to take more concentrated air traffic load It requires additional space of 15 m so as to keep
outermost part of jet engine aircrafts on paved
surface
To protect the possible damage to the farthest
machinery
Engine damage from ingestion of loose material of
shoulders
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Runway Geometric
Runway Width
As per ICAO (in meters)
Code Letter
Code Number A B C D E
1 18 18 23 - -
2 23 23 30 - -
3 30 30 30 45 -
4 - - 45 45 45
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Runway Geometric
Runway Width
In case of ICAO code number 1 and 2, if precisionapproach runway is used then width should not be
less than 30 m. Width of 45 m is sufficient for large airports.
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Runway Geometric
Safety Area Landing strip
Paved area + shoulder
Shoulders Useful during emergency landing or take-off
Not meant for regular application of load
Are usually of lesser strength pavements and are
provided on both sides of the runway strip Impart physiological improvement
Openness to the pilots
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Runway Geometric
Shoulders
Sometimes stablised
To resist jet blast erosion
To accommodate maintenance/emergency equipment Shoulders for small airports may be turfed
Safety area
Width of safety area as per ICAO Non-instrumental runway 75 m (min.)
Instrumental runway 150 m (min.)
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Runway Geometric
Blast pad
Area constructed at the ends of the runway that
serve jet operations
To prevent erosion of surfaces adjacent to runway ends
Extends across full width of runway and its both
side shoulders
Essentially non-traffic area
Varies in length from 30 m to 120 m
Depends up on type of aircraft to be served
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Runway Geometric
Runway Gradient Longitudinal grade and grade change
Level runway is ideal for safe aircraft operations
Cost of excessive earthwork precludes its design Longitudinal gradients should be as flat as possible
To avoid excessive engine thrust
Should not restrict sight distance
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Runway Geometric
Runway Gradient
Longitudinal grade and grade change
Changes in longitudinal gradient should be smooth
Through provision of vertical curves
Abrupt grade change
Cause premature lift off of aircrafts during take-off
Grade changes should not be very frequent
Restrict sight distance and increase runway length
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Runway Geometric
Runway Gradient
Longitudinal grade and grade change
ICAO limits the maximum longitudinal gradient of
1.25 to 1.5 percent for runways that serve the
largest type of aircraft (Code 3 & 4) 2 percent for small aircrafts (Code 1 & 2)
Flatter grades should be provided in first and last
quarters of runways
0 to 0.8 percent
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Runway Geometric
Runway Gradient Longitudinal grade and grade change
ICAO has specified minimum distance between
points of grade intersections of two successivegrade changes
Based on sum of absolute values of corresponding
grade changes
No vertical curve is required when grade change isless than 0.4 percent
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Runway Geometric
Rate of Change of Longitudinal Gradient
a
b
yxz
D
L1L2
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Runway Geometric
Rate of Change of Longitudinal Gradient
Grade Design Criteria (ICAO)
ICAO Max Max grade Max. Max. Distance Length
code Long. First & last Effec. Grade Bet. Points of
No Grade quarter Grade Change of grade vertical
% grade % % intersection(m) curve (m)
4 1.25 0.8 1.0 1.5 300 (A+B) 300 A or B
3 1.5 0.8 1.0 1.5 150 (A+B) 150 A or B
2 2.0 - 1.0 2.0 50 (A+B) 75 A or B
1 2.0 - 2.0 2.0 50 (A+B) 75 A or B
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Runway Geometric
Transverse Gradient
Provided for quick disposal of surface water
Ponding of water is hazardous for aircraft operation
Minimum recommended transverse slope is 1
percent for flexible pavement
For rigid pavement it may be kept as low as 0.5 percent
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Runway Geometric
Transverse Gradient
Slope up to 2 percent are permitted for runways
that serve smaller aircrafts (ICAO Reference
Code A and B) For others, maximum is 1.5 percent
Shoulders require steeper slopes
Slope of up to 5 percent is permitted for first 3 m
beyond pavement edge
1.5 3 percent thereafter
FAA recommends a 4 cm drop from the paved
runway surface to the graded shoulder surface
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Runway Geometric
Transverse Gradient
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Runway Geometric
Sight Distance
Should be as unrestrictive as possible
Generally no sight distance restrictions as the
longitudinal gradients for the runway are quite gentle Adherence to runway longitudinal gradient standards provides
adequate line of sight
Hazardous locations are crossings of two runways or
runway and taxiway
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Runway Geometric
Sight Distance (ICAO recommendation)
Airport category Y (meter) X
ICAO code letter A 1.5 half runway length
ICAO code letter B 2.1 Half runway length
ICAO code letter C, 3.0 Half runway length
D, E
Runway grade should be such that any two points Y
meters above runway centerline will be mutually visible
for a minimum distance of X