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Design of Taxiway: Prof. Ashok Kumar

The document discusses the design of taxiways. It defines a taxiway and lists its key geometric standards including length, gradients, sight distance, widths, and turning radii. It provides recommended standards from ICAO for these features for different airport types. Equations are given for calculating turning radii using speed, wheelbase, tread, and friction coefficients. The design of exit taxiways is also covered, including lengths of entrance/central curves and stopping distances using speed. An example problem calculates dimensions for a taxiway layout.

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Ashok Kumar Rajanavar
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150 views10 pages

Design of Taxiway: Prof. Ashok Kumar

The document discusses the design of taxiways. It defines a taxiway and lists its key geometric standards including length, gradients, sight distance, widths, and turning radii. It provides recommended standards from ICAO for these features for different airport types. Equations are given for calculating turning radii using speed, wheelbase, tread, and friction coefficients. The design of exit taxiways is also covered, including lengths of entrance/central curves and stopping distances using speed. An example problem calculates dimensions for a taxiway layout.

Uploaded by

Ashok Kumar Rajanavar
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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19-04-2020

Design of Taxiway
Prof. Ashok Kumar

Learning Outcomes
At the end of lecture, students will be able to
design the geometric features of taxiway

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19-04-2020

Taxiway
A taxiway is a path on an airport
connecting runways with ramps, hangars,
terminals and other facilities. They mostly
have hard surface such as asphalt or
concrete, although smaller airports sometimes
use gravel or grass.

Taxiway

Source: https://www.century-of-flight.net/

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19-04-2020

Typical C/S of Taxiway

Geometric Standards of Taxiway


1. Length of Taxiway
2. Longitudinal Gradient
3. Rate of change of longitudinal Gradient
4. Sight Distance
5. Transverse Gradient
6. Turning Radius
7. Width of safety Area
8. Width of Taxiway

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Sl. Geometry Features Recommended Value as per ICAO


No
1 Length of Taxiway -As short as possible
-Depends on distance between apron and entry end or exit end of runway
2 Longitudinal gradient If gradient is steep it affects fuel consumption
-1.5%-A & B types Airports, 3.0%-C, D & E Airports
3 Rate of change of 4%-A & B Airports, 3.33%-C, D, & E Airports
longitudinal Gradient
4 Sight Distance -As speed of aircraft on taxiway is lower than the speed on runway, the
smaller value of sight distance will be sufficient on the taxiway.
-ICAO recommended that the surface of taxiway must be visible at least up to
a distance of X- from any point at a height of Y above the taxiway surface.
5 Transverse Gradient Should not exceed 1.5% for A,B&C, & 2% for D&E types

6 Turning Radius Radii corresponding of taxing speeds of small, subsonic & supersonic
airplanes is 60 m, 135 m & 240 m respectively.
7 Width of Taxiway A-22.5m, B-22.5m, C-10.5m, D-9.9m, E Airport-7.5m

Taxiway Geometric
1.Turning Radius: Circular radius of large radius is most
suitable: 𝑉2
𝑅=
125𝑓
R = radius of curve in m
V = speed of aircraft in km p.h.
f = coefficient of friction between the tyre and pavement
surface (usually assumed as 0.13).
Min value of radius of curvature is taken as 120 m &180 m
supersonic jet planes.

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19-04-2020

Taxiway Geometric
2.Turning Radius: Using Horonjeff equation:
0.388𝑊 2
𝑅=
0.5𝑇 − 𝑆
R = radius of curve in m
W = Wheel base of aircraft, m
T= Width of Taxiway Pavement=22.5m.
S=Distance between point midway of the main gears and
the edge of the taxiway pavement.

Taxiway Geometric
S = 6 + (Wheel tread/2)

Wheel tread

S 6m

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Design of Exit Taxiway


1. Lengths L1 and L2: The values of L1
and L2 can be obtained by using the
following equations:
𝑉3 Π𝑅2𝐷2
𝐿1 = 𝐿2 =
45.5𝐶𝑅2 180
R1 = Radius of entrance curve
R2 = Radius of central curve
L1 = Length of entrance curve
L2 = Length of central curve.

The value of constant C is 0.39 and D2 is the deflection angle of the central curve.

Design of Exit Taxiway


2.Stopping Distance: It is necessary to provide sufficient distance
to comfortably decelerate an aircraft after it leaves the runway:

𝑉2
𝑆. 𝐷 =
25.50𝑑
d=average deceleration rate is usually taken as 1m/sec2
3.Turning Radius: The turning radius for smooth and comfortable
turn is calculated by 𝑉2
𝑅=
125𝑓

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Example

D=D1+D2
350=‘50 45’+D2
D2=350 - ‘50 45’=29015’

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Taxiway
22.5m

217.75m

350
45m
Runway

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350

1450
60m Radii

22.5m Radii

Fillets
Angle of Intersection Small Airport Large airport
0-450 7.5m 22.50m
450-1350 15m 30m
>1350 60m 60m
The radii of fillet should not be less than the width of the
Taxiway

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