transportation engg.- intro. to infrastructure.pdf

8/17/2019 Transportation Engg.- Intro. to Infrastructure.pdf

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TRANSPORTATION

ENGINEERING

Institute of Infrastructure, Technology

Research and Management (IITRAM)

Road Development in India

Ancient Development

History of road construction

• Aryan period

• Mauryan period:

• Emperor Ashoka

• Mughal period

• Roads during the British rule

• Appointment of Jayakar committee (1927)

• Creation of central road fund (1929)

• Indian roads congress (1934)

• Central road research institute (1950)


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Role of Road Transportation

• Social: Formation of settlements, Size and pattern of

settlements, Growth of urban centres

• Economical: The place, time, quality and utility of

goods, Changes in location of activities

• Political: Administration of an area, Political choices

in transport

• Environmental: Safety, Air Pollution, Noise pollution

Energy Consumption

• Other Impacts: Land consumption, Parking,

Aesthetics, Social life Affected

Jayakar Committee Recommendations

• Road development should be considered as anational interest

• Central road fund: Extra tax on petrol to develop

road development fund

• Semi-official technical body to pool technical

knowledge from various parts of the country and

act as advisory body (IRC)

• Research organization to carry out research and

development work and consultancy work.(CRRI)

Central Road Fund

• 1st March 1929

• Extra levy of 2.64 paisa per liter (2anna /gal)

• 20% retained as central reserve for administration and research of roadand bridge

• 80% to be allotted to state govts based on petrol consumption.

• Presently Rs. 2 per litre is collected as cess on Petrol and High speedDiesel oil(HSD).

• Allocation:

• Rs 0.5/lit for development and maintenance of NH

• Rs 1.50: (i) 50% from HSD for rural road

(ii) 50% from HSD and entire of Petrol as:

(a)57.5% for Dev and Maintenance of NH(b) 12.5% for Road over and Under bridges and

Unmanned railway crossing.

(c)30% for Dev and maintenance of State roads

Indian Road Network

• Indian road network of 33 lakhKm.is second largest in theworld and consists of :

• Length(In Km)Expressways:2000

• National Highways: 79,243

• State Highways :1,31,899• Major District Roads :4,67,763

• Rural and Other Roads :26,50,000

• Total Length :33 Lakhs Kms

• (Approx)Modal Shift: About 65% of freight and 80% passengertraffic is carried by the roads.

• National Highways constitute only about 1.7% of the roadnetwork but carry about 40% of the total road traffic.

• Number of vehicles has been growing at an average pace of10.16% per annum over the last five years


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Geometric Design of Roads

Deals with visible dimensions of a roadway and is dictated by:

Horizontal and vertical alignments (incl. Curves) Sight distances

Cross-section components (Longitudinal, Lateral)

Intersection treatment

Control of access

Requirements of traffic

Mumbai-Pune Expressway

Mumbai-Pune Old status

Topography Affects Geometric Design


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Kathipara Interchange, Chennai Elements involved in Geometric Design of

Highways

Geometric Design of Highways

Cross sectional elements Width of pavement, formation and land, the

surface characteristics and cross slope of pavement

Sight distance considerations Horizontal curves, vertical curves, intersections

governs the safety of highways

Horizontal alignment details Change in road direction, type of horizontal

curve, superelevation, extra pavement width,transition curves

Design speed

Important for economic operation and safety

• Considerable variation in speed depending on drivers and

kind of vehicle.

• Value selected should accommodate nearly all demandsand should not fail under severe or extreme cases

• Design speed is determined for design and correlation of

physical features of highway that influence vehicle

operation

• Maximum safe speed that can be maintained whenconditions are so favorable that design features of

highway govern.

• Design speed must be correlated with terrain conditions

and highway class.

Suggested design speeds in kmph for rural

highways

Plain Rolling Mountainous Steep

R M R M R M R M

NH and SH 100 80 80 65 50 40 40 30

MDR 80 65 65 50 40 30 30 20

ODR 65 50 50 40 30 25 25 20

VR 50 40 40 35 25 20 25 20

R: Ruling

M: Minimum


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Suggested design speeds in kmph for urban

streets in India

Arterial………………………. 80

Sub-arterial ………………… 60

Collector street ……………. 50

Local street ………………… 30

Carriageway

Road way

Road land widthSet

Back

Overall width between Building Lines

Overall width between Control Lines

SetBack

Formation width in

cutting

Sight Distance Elements

• Stopping sight distance

• Overtaking sight distance

Stopping sight distance

• Highway with adequate sight ahead of a travelling vehicle

results in safe operation.

• Distance along road surface at which a driver has visibility of

objects, stationary or moving, at a specified height abovecarriage way is known as sight distance.

• Stopping sight distance is the distance required by a driver

of a vehicle travelling at a given speed to bring her/his

vehicle to stop after an object on the roadway become

visible.

• Stopping sight distance is made up of two components:

distance travelled during perception and brake reaction time

Distance travelled during the time brakes are under

application till the vehicle stops.


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STOPPING SIGHT DISTANCE

Lag Distance

Distance Travelled during

Reaction Time

Braking Distance

Distance Travelled after

application of brakes

Stopping sight distance…

• Perception and brake reaction time depend upon factors

such as: age, sex, alertness, visibility etc.

• IRC suggests 2.5sec a reasonable value for perception

and brake reaction time.

• Thus distance travelled during perception and brake

reaction time is:

d1 = v t

= 0.278 V t

d1 = distance travelled in m

v = speed in m/sec

V = speed in kmph

t = perception and reaction time = 2.5 sec

Stopping sight distance…

• Braking distance is the distance required for a movingvehicle to stop after application of brakes:

d2 = V2

/ 254f d2 = braking distance in metres

V = speed in kmph

f = coefficient of longitudinal friction between tyre and thepavement (assumed to vary between 0.40 at 20kmph and0.35 at 100kmph)

Stopping sight distance = d1 + d2= Vt + V2 / 254f

VEGETATION BLOCKING THE SIGHT ON A HORIZONTAL CURVE


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SIGHT DISTANCES AT VERTICAL CURVES ARE

AFFECTED BY GRADIENT. FLATTER SLOPES

PROVIDE HIGHER VISIBILITY

Road Edge

Outer

Edge

Road Edge

Inner

Edge

Actual super elevation, E = e B

PROVISION OF SUPER ELEVATION

NORMAL ROAD SECTION ON A STRAIGHT

ROAD

Analysis of Superelevation..

• Maximum super-elevation values:

• IRC recommends for hilly areas: 0.07 for snow-bound

areas, 0.10 for areas not affected by snow

• All other cases, a value of 0.07 is considered maximum

• Minimum radii of curves:

V2/ 127R = e + f

R = V2/ 127 (e + f)

• Knowing e and f, it is possible to calculate the minimum

radius

Typical calculations

Minimum Radius of Curve ,R = V2/127( e + f )

If V= 50 KMPH, e = 0.07, f = 0.15

R = 89 m, say 90 m


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Transportation EngineeringText books:

1. Khanna S.K., Justo C.E.G.,Highway Engineering, Nem Chand & Bros., Roorkee, 2001

2. KadiyaliL.R., Principles & Practice of Highway Engineering, Khanna Publishers,2003

• Web sites:

• www.nhai.org

• www.morth.gov. in

• www.irc.in

• www.moud.gov.in

transportation engg.- intro. to infrastructure.pdf

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