DOCK, HARBOUR & AIRPORT ENGINEERING

AIRPORT DESIGN 1

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GEOMETRIC DESIGNRunwayRunway orientationBasic Runway lengthRunway configurationRunway GeometricsTaxiwayExit taxiwayTerminal Design2

RUNWAYA runway is a rectangular area on the airport surface prepared for the takeoff and landing of aircraft. An airport may have one runway or several runways which are sited, oriented, and configured in a manner to provide for the safe and efficient use of the airport under a variety of conditions. Several of the factors which affect the location, orientation, and number of runways at an airport include local weather conditions, particularly wind distribution and visibility, the topography of the airport and surrounding area, the type and amount of air traffic to be serviced at the airport, aircraft performance requirements, and aircraft noise.3

RUNWAY ORIENTATIONRunway are always oriented in the direction of prevailing winds.The reason behind this is to utilize the maximum force of the wind at the time of take-off and landing of an aircraft.Following points need to be considered while orienting the runways:Avoiding delay in the landing, taxing and take-off operations.Providing the shortest taxi distance possible from the terminal area to the ends of runway.Making provision for maximum taxiways so that the landing aircraft can leave the runway as quickly as possible to the terminal areaProviding adequate separation in the air traffic pattern4

Data required for runway orientationMap of area and contoursWind dataWind Direction: Tail Wind, Cross Wind & Head WindFog characteristicsICAO recommends maximum allowable cross wind components as

Field LengthMaximum CW component1500 or over37 km/hr1200 to 1499 m24 km/hrLess than 1200 m19 km/hr

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Wind CoverageWind coverage of airport is the percentage of time in a year during which the cross wind component remains within the limit or runway system is not restricted because of excessive cross wind. ICAO recommends minimum wind coverage of 95%Calm PeriodThis is the period for which the wind intensity remains below 6.4 km/hrWind Rose DiagramType 1: Duration and Direction of windType 2: Duration, Direction and Intensity of wind6

BASIC RUNWAY LENGTHThe FAAs procedure for estimating runway length is based on the following data: Designation of a critical aircraft.The maximum takeoff weight of the critical aircraft at the airport.The airport elevation.The mean daily maximum temperature for the hottest month at the airport.The maximum difference in elevation along the runway centerline.

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Correction for ElevationAs the elevation increases, the air density reduces. This in turn reduces the lift on the wings of the aircraft and the aircraft requires greater ground speed before it can rise into the air. To achieve greater speed, longer length of runway is required.ICAO recommends that the basic runway length should be increased at the rate of 7% per 300m rise in elevation above MSL.8

Correction for TemperatureThe rise in airport reference temperature has the same effect as that of the increase in elevation. Airport reference temperature is defined as the monthly mean of average daily temperature (Ta) for the hottest month of the year plus one third of the difference of this temperature and the monthly mean of the maximum daily temperature (Tm)Airport reference temperature = Ta + [(Tm Ta)/3] 9

ICAO recommends that the basic runway length after having been corrected for elevation, should be further increased at the rate of 1% for every 10 C rise of airport reference temperature above the standard atmospheric temperature at that elevation.The standard atmospheric temperature at the site can be determined by reducing the standard sea level temperature of 150 C at the rate of 6.50 C per 1000 m rise in elevation.

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Check for Total Correction for Elevation and TemperatureICAO further recommends that, if the total correction for elevation plus temperature exceeds 35% of the base runway length, these corrections should then be further checked up by conducting specific studies at the site by model tests.Correction for GradientSteeper gradient results in greater consumption of energy and as such longer length of runway is required to attain the desired ground speed. FAA recommends that the runway length after having being corrected for elevation and temperature should be further increased at the rate of 20% for every 1% of effective gradient.11

RUNWAY LENGTH CURVE

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Basic Runway LengthNormal LandingThe aircraft should come to a stop within 60% of landing distance assuming that the pilot makes an approach at the proper speed and crosses the threshold of the runway at a height of 15m.The runway of full strength is to be provided for the entire landing distance

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Normal Take-offThe take-off distance must be 115% of the actual distance the aircraft uses to reach a height of 10.5 m.It requires a clearway at the end of the runway in the direction of take-off. This should not be less than 15m wide. The upward slope of clearway from the end of the runway shall not exceed 1.25%

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Stopping in EmergencyRequire either clearway or a stopway, or both. (Stopway: Used for decelerating the aircraft and bringing it to a stop during an aborted take-off.)

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RUNWAY CONFIGURATION17

RUNWAY GEOMETRICSLength of runwayWidth of runwaySight distanceLongitudinal and effective gradientRate of Change of longitudinal gradientTransverse gradientSafety area18

Length and Width of RunwayClassifications of airports as per ICAO

Airport TypeBasic Runway Length (m)Width of Runway Pavement (m)Maximum Longitudinal Gradient (%)MaximumMinimumAOver 21002100451.5B20991500451.5C1499900301.5D89975022.52.0E749600182.0

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Sight DistanceNo sight distance restrictions, as the longitudinal gradients for the runway are less.Adherence to runway longitudinal gradient standards provides adequate line of sight.

Airport CategoryY (m)XICAO code letter A1.5Half runway lengthICAO code letter B2.1Half runway lengthICAO code letter C,D and E3.0Half runway length

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Longitudinal GradientThe longitudinal gradient increases in required runway length.It also affects the aircraft performance.These should be as flat as possible to avoid excessive engine thrust21

Change of Longitudinal GradientThe abrupt grade change may cause premature lift-off of aircraft during take off.The change in gradient should be smooth through the provision of vertical curves.No vertical curve is required if the grade change is less than 0.4 %. 22

Transverse GradientProvided for quick disposal of surface water.Ponding of water is hazardous for aircraft operation.Minimum recommended transverse slope is 1%.For rigid pavement it may be kept as low as 0.5.Slope up to 2% are permitted for runways that serve smaller classes of aircraft. For other runways maximum transverse slope is 1.5%.For shoulders slope of 3-5% is recommended.23

Safety AreaThe safety area is an area which is cleared, drained and graded. It includes the structural pavement, shoulders on either side of runway and the additional width.

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TAXIWAYTaxiway are defined as paths on the airfield surface for the taxing of aircraft and are intended to provide linkage between one part of the airfield.Aircraft movement on taxiways are essentially ground movements and are relatively slow.25

Types of taxiwayApron taxiway: Located on the periphery of an apron to provide uninterrupted taxing of aircraft across the apron.Dual parallel taxiway: Two parallel taxiways on which aircraft can taxi in opposite directions.Terminal taxiway: It is a portion of an apron intended to provide access to only aircraft stands or gate positions.26

Taxiway GeometricsLengthAs short as possibleIt will increase as number of taxiways have to be provided along the runway.Longitudinal GradientLevel taxiways are operationally more desirableIf gradient is steep it affects fuel consumptionAs per ICAO gradient of 3% for A and B types of airport and 1.5% for C, D and E types of airport.27

Width of taxiwayWidth of taxiway is lesser than runway, as aircraft is not airborne and speeds are small.There is not much variability in the maneuverability of aircraft and nose of aircraft follows the taxiway centerline.Width varies between 22.5 and 7.528

Sight distanceAs speed of aircraft on taxiway is lower than the speed on runway, the smaller value of sight distance will be sufficient on the taxiway.

Airport TypeY (m)X (m)A1.5150B2.0200C, D and E3.0300

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Turning RadiusChange in aircraft path is done by providing a horizontal curve.The design should be such that the aircraft can negotiate the curve without significantly reducing the speed.Relationship between exit speed and radius of curveRadius = V2/125f; V is in Kmph and f is coefficient of friction =0.1330

ICAO has indicated the relationship between aircraft speed and the radius of curvature of taxiway curves as illustrated in Table.TAXIING SPEED(kmph)RADIUS OF EXIT CURVE (m)1615326048135642408037596540

Source: International Civil Aviation Organization31

Radii of curvature and entrance curves for Taxiways

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EXIT TAXIWAYThe function of exit taxiways, or runway turnoffs as they are sometimes called, is to minimize runway occupancy by landing aircraft.Exit taxiways can be placed at right angles to the runway or some other angle to the runway. When the angle is on the order of 30, the term high-speed exit is often used to denote that it is designed for higher speeds than other exit taxiway configurations.33

HIGH SPEED EXIT TAXIWAY

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COMMON EXIT TAXIWAY CONFIGURATION

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FAA Taxiway Curvature Dimensional Standards (ft)

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TERMINAL AREAIt is portion of an airport other than landing area.It serves as a focal point for the activities on the airport.Terminal area includesTerminal and operational buildingsVehicle parking areaAircraft service hangarsFacilities for cargo handling and storageFacilities for passengers37

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Terminal building usually refers to a building mainly, used for passengers, airline and administration facilities. Its layout is such as to offer the enplaning passengers, the convenient and direct access from the vehicle platform or street side of the building, through booking and waiting rooms, to the aircraft loading positions on the apron.Deplaning passengers are also provided with a direct route from the aircraft to the baggage claim counter and then to the vehicle platform.39

GENERAL AIRPORT TERMINAL LAYOUT

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CONCEPTFOR TERMINAL DESIGNHorizontal distribution conceptPier or finger conceptSatellite conceptLinear conceptTransporter conceptVertical distribution concept41

Horizontal distribution conceptPier or finger concept:The pier concept has an interface with aircraft along piers extending from the main terminal. Aircraft are usually arranged around the axis of the pier in a parallel or nose-in parking alignment.Each pier has a row of aircraft gate positions on both sides, with a passenger concourse along the axis which serves as the departure lounge and circulation space for both enplaning and deplaning passengers.

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Satellite concept:The satellite concept consists of a building, surrounded by aircraft, which is separated from the terminal and is usually reached by means of a surface, underground, or above ground connector.The aircraft are normally parked in radial or parallel positions around the satellite.Linear concept:The simple linear terminal consists of a common waiting and ticketing area with exits leading to the aircraft parking apron.It is adaptable to airports with low airline activity which will usually have an apron providing close-in parking for three to six commercial passenger aircraft43

Transporter concept:Aircraft and aircraft servicing functions in the transporter concept are remotely located from the terminal.The connection to the terminal is provided by vehicular transport for enplaning and deplaning passengers.44

Terminal TypesLinearCurvilinear45

Finger Piers

Satellite

Transporter

Satellite46

VERTICAL DISTRIBUTION CONCEPTThe basis for distributing the primary processing activities in a passenger terminal among several levels is mainly to separate the flow of arriving and departing passengers.The decision concerning the number of levels a terminal facility should have depends primarily on the volume of passengers and the availability of land for expansion in the immediate vicinity.47

VERTICAL DISTRIBUTION CONCEPT: (a)single level (b)second level loading (c)two level system. (FAA) 48

The operational category includes control tower, weather bureau and other government services related to the aviation. In many cases terminal building fulfils the function of the operational building as wellThe various facilities provided in the airport buildings are as follows:

Booking counterBaggage claim sectionEnquiry counterSpace for cargo processingPublic telephone boothWaiting hallSanitation facilitiesRestaurants/HotelsFirst aid roomGeneral store and gift shopsSpace for magazines, news papers etcOffice space for airport staffWeather bureauPost office and banking facilitiesCustom controlPassport and health controlControl tower

FAA suggests that the terminal building area should be based on the present and future peak-hour passenger activities projected over a period of 10 years.49

TERMINAL BUILDING SPACE REQIREMENTComponentSpace Required in meter square Typical PeakHour per PassengerTicket lobby1.0Baggage claim1.0Departure lounge2.0Waiting rooms1.5Immigration1.0Customs3.0Amenities2.0Airline operations5.0Total gross areaDomestic25.0International30.0

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REFERENCEPlanning and design of airports.Robert horonjeff.Francis x. makelvey.William j. sproule.Seth b. young.Airport system.Richard de neufvilleAmedeo R. odoniTransportation engineeringPaul H. wrightNorman J. ashford51