8/9/2019 Highway Engineering TRAN 3001 Lecture 1

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TRAN3001Highway Engineering Lecture 1

Introduction

Terminology

Highway Location

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Introduction

Purpose o Highways

Transport o people! goods and ser"ices#

Highway EngineeringHighway engineering is a $ranch o ci"ilengineering that deals with the design!

construction and maintenance odi%erent types o roads#

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Terminology

Highway as de&ned in the local 'T(T)Highways Act '*hapter +,-01) means anyroad! street! etc# .maintainable at the

public expense and dedicated to thepublic use# .

Pavement / the pa"ed 'asphalt or portlandcement concrete) section o a highway#

Carriageway / the section o a highwaydesigned or use $y "ehicular trac# Alsocalled the tra"elled or motor way#

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Terminology '*ontd)

Shoulders 2 hard suraces adacent tothe carriageway! which may $e eitherpa"ed or unpa"ed# They are intended

primarily or saety as they canaccommodate stopped "ehicles andemergency use and also pro"ide lateralsupport#

Sidewalk2 also called a ootpath!adacent to a road or road drain! intendedor use only $y pedestrian trac#

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Terminology '*ontd)

Road Reserve 2 an area within whichcarriageways! shoulders! ootpaths!drainage! street lighting and associated

eatures may $e constructed or pu$lictra"el#

A suciently wide road reser"e will permitthe construction o gentle slopes whichresult in greater saety or motorists andena$les easier and more economicalmaintenance#

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Terminology '*ontd)

Median / longitudinal $arrier used to separateopposing directions o trac on a di"idedhighway#

Culvert2 a structure 'conduit) which carrieswater under a road! i#e# the top o the cul"ert isalways $eneath the carriageway#

Bridge 2 a structure which carries a road across

a ri"er! etc#! i#e# the top o the $ridge orms parto the carriageway#

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Highway Location

Particularly or maor highways re4uiring a largecapital in"estment! selecting the route $etweenthe two points 'or e5ample 6an 7ernando to Point7ortin) re4uires careul and detailed in"estigation

to arri"e at the most economical solution#

6ources o inormation -

cadastral maps / these include land use andproperty $oundaries#

topographic maps/contour lines on thesemaps show the di%erent land ele"ations#

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Highway Location '*ontd)

6ources o inormation '*ontd) -

geological and soil maps2 indicate typeo su$surace and soil conditions that may

$e e5pected# aerial photographs 2 can pro"ide the

most up to date inormation on land use!etc#

hydrological data 2 includes records orainall! and stream8ow 'hydrograph) ordrainage design#

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Highway Location '*ontd)

6ources o inormation '*ontd) -

reconnaissance survey2literallywal9ing one or more possi$le routes to

gather physical inormation a$out theareas under in"estigation#

local knowledge 2 "alua$le inormationon 8ooding! proposed construction and

other eatures o the proposed routes can$e o$tained rom residents and othersamiliar with the areas#

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Highway Location '*ontd)

:uidelines or selecting the route -

as direct as possi$le#

away rom highly de"eloped e5pensi"e

property# along the edges o properties rather than

through the middle to minimise intererenceand land ac4uisition costs#

a"oid destruction or remo"al o cemeteries!places o worship and culture! schools andhospitals#

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Highway Location '*ontd)

:uidelines or selecting the route' *ontd)-

higher ground rather than "alley areas

to reduce drainage concerns#

a"oid locations where 'e5pensi"e) roc9e5ca"ation is re4uired#

a"oid wetlands and otheren"ironmentally sensiti"e areas

close to sources o pa"ement materials

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Highway Location '*ontd)

:uidelines or selecting the route ' *ontd)-

as ar as possi$le on the route o ane5isting highway to reduce costs#

a"oid locations prone to landslides whichwill result in increased costs with there4uirement or retaining walls#

a"oid locations with poor soils whichre4uire more e5pensi"e pa"ementconstruction#

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Highway Location '*ontd)

:uidelines or selecting the route ' *ontd)-

a"oid locations with e5tensi"e planned ore5isting pu$lic utilities which would need to $e

remo"ed or relocated# a"oid locations at right angles to the 'maor)

natural drainage channels to reduce drainagecosts#

In practice the selected route is the $estcompromise solution#

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Highway Location '*ontd)

6ite 6ur"ey

;ne 'or more) o the easi$le routes issur"eyed to collect all the physical

inormation that can a%ect the highway! suchas the slope o the ground! position and in"ertle"els o the natural drainage! utilities! housesand other property#

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Highway Location '*ontd)

6ite 6ur"ey '*ontd)

The result o the sur"ey along the proposedcentreline o the road is the hori=ontal

alignment! e5isting ground slopes>grades andcross sections#

The preerred location would $e the one thatminimises the cost o earthwor9s! which is the

case when the 4uantities resulting rome5ca"ation 'cut) match the 4uantities re4uiredor em$an9ment construction '&ll)! a"oiding theneed or haulage and imported material#

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Highway Location '*ontd)

6u$surace E5ploration

This is carried out to determine thetype! location and e5tent o soil androc9 to $e encountered on theproposed route as well as the deptho the water ta$le#