CE-363

Lecture 11: Airport Capacity, Hangars

and Airport Pavement Design

Dr. Ankit Gupta, Assistant Professor

Department of Civil Engineering

National Institute of Technology Hamirpur

Lecture Outline

Airport Capacity

Hangars

Airport Capacity

The number of aircraft movements which an airport can process within a specified period of time, with an average delay to the departing aircraft within the acceptable time limit.

Practical operating capacity is less than the ideal capacity, depending upon the amount of acceptable delay to the departing aircraft.

Airbourne Instruments Laboratory USA, has fixed an average delay period of 6 minutes.

Airport Capacity

The factors affecting the airport operating capacity:

Runway configurations and the connected taxiways.

Aircraft characteristics and their arrival to departure ratio.

Weather conditions.

Terrain and man-made obstructions.

Landing apron space.

Navigational aids.

Aircraft processing techniques.

Runway Capacity

Ability of a runway system to accommodate aircraft landings and take-off. It is expressed in operations per hour or operations per year.

Ultimate or Saturation capacity of a runway is the maximum number of aircraft that can be handled during a given period under conditions of continuous demand.

Factors affecting runway capacity are:

Air traffic control

Characteristics of demand

Environmental factors

Layout and design of the runway system

Hangars

These are enclosures for housing and repairing of aircrafts

Steel framework with galvanized iron sheets are provided

Space is provided for machine shops and stores for spare parts

Size depends upon size of aircraft and turning radius

Number of hangars depends upon peak hour intensity and demand from airlines

Adequate lighting should be provided inside the hangar

Hangars

Location should be as near to the loading aprons and terminal building as practicable

Facilities like water supply, telephone, drainage etc. should be available

Favourable topography with good natural drainage helps in keeping it dry

It should not be along the direction of frequent wind storm

Space should also be allocated for accommodating personal, vehicles etc.

Space requirement for future expansion.

Hangars

Types of storage and service hangars

Nose hangar

Provided for large sized aircraft

Comfortable working conditions

Economical

T-hangar

Provided for small sized aircraft

Encloses the aircraft fully

Hangars

Airport Pavement Design

Flexible: Deformations in layers, have some flexural strength

Rigid: No deformations, act as a beam. Negligible flexural strength.

Types of Design:

Empirical: CBR, Plate bearing, etc.

Semi-empirical: Burmister’s approach, etc.

Analytical: Westergaard analysis, etc.

Airport Pavement Design

Various design factors are:

Design wheel load

Strength characteristics of materials used in layers

Subgrade supporting capacity

Other factors like repetition of wheel loads, fatigue resistance, impact, volume change due to frost-thawing, etc.

Airport Pavement Design

Design methods for flexible pavements:

CBR Method

McLeod Method

Burmister Method

Analytical Method

Computer Aided Design (CAD) applications

Design methods for rigid pavements:

Westergaard’s Method

LCN/PCN/ACN system of pavement design

Airport Pavement Design

Load Classification Number: A system of classification of the supporting capacity of pavements, indicating their ability to support loads without cracking or becoming permanently deformed. The number is obtained by making plate-bearing tests on the pavement. Likewise, the equivalent single-wheel load of any aircraft can be expressed in terms of LCN.

LCN is dependent on the gear geometry, tire pressure, and the composition and thickness of the pavement.

Thus, if the LCN of an airfield pavement is larger than the LCN of the aircraft, the aircraft can safely use the pavement.

Airport Pavement Design

Aircraft Classification Number: It is a number expressing the relative effect of an aircraft on the runway pavement for a specified standard subgrade category (ICAO).

Pavement Classification Number: It is an ICAO standard used in combination with the ACN to indicate the strength of a runway, taxiway or apron. This helps to ensure that the apron is not subjected to excessive wear and tear, thus prolonging its life.