Design of Rotary

8/18/2019 Design of Rotary

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AND STANDARDGEOMETRIC DESIGN AT

HUNTER ROAD,WARANGAL

SR ENGINEERING COLLEGE

A.ANIL KUMAR - 11K41A0109

E.RAVICHANDER - 11K41A0120 D.SOUMYA - 12K45A0103

A.KARTHIK - 11K41A0108

K.MOUNIKA - 12K45A0106

K.KARUN KUMAR - 11K41A0148 CH.MOUNIKA - 11K41A0116


2/39

Name of the workwidening of hunter road 2 lane to 4 lane in warangal

limits in warangal district. Sub!or"#

$ro%iding road safet& inter%entions b& construction of

rotar& and "idne& islands at "m.'()* of +unction of

hunter road in warangal district.

,he +unction is a -+unction RO/ lin" road towards"hammam starts from this -+unction thus the +unctionneeds to be im$ro%ed to a%oid fatal accidents.

It is $ro$osed with owl sha$ed rotar& with "idne& islandsone each on hanam"onda warangal and "hammam sides.


3/39

0esign of Rotar&

0e1nitions# t grade intersection# an intersection is where all roadwa&s +oinor cross at

the same le%el.

0i%erging# di%iding of a single stream of tra3c into se$aratestreams.

Intersection angle# the angle between two intersection legs.

erging# the con%erging of se$arate streams of tra3c into asingle stream.

Rotar& Intersection# road +unction laid out for mo%ement of

tra3c in one

direction around a central island.

Rotar& Island# tra3c island located in the centre of anintersection to

com$el mo%ement in a cloc"wise direction and thus substitute

wea%ing oftra3c around the island instead of direct crossing of %ehicle


4/39


5/39

ob+ecti%es#

Signali5ation of rotaries to $ro%ide access to $edestriansand

%ehicles.

,o e%aluate $ercei%ed concern of high s$eed at rotaries .

,o balance tra3c %olume.

,o mo%e the %ehicles in circulator& motion without

confusion.

6idne& islands are $ro%ided to reduce the s$eed of the%ehicles as the

%ehicles come nearer to the +unction $oint.


6/39

%t$&'

,ra3c %olume stud& is done b& counting b& following methods#

7. echanical Counters

In mechanical counters method tra3c count is recorded b&

electricall& o$erated counters.

other methods of wor"ing the mechanical detectors are b&

•.

$hotoelectric cells

•. magnetic detectors

•. radar detectors


7/39

Ma($a# "o$(t%

anual counts are recorded in a $rescribed record sheet#

anual count from 8anam"onda to warangal

$$roach

Straight

ahead

Right turning Left turning

car

s

Comm

ercial

%ehicle

s

2

!heele

rs

cars

Comm

ercial

%ehicle

s

2

!heeler

s

Cars Comm

ercial

%ehicle

s

2!

North

79)

749 ')2 7'2 *) 2:9

South 729 492 7*2 74' 4:2


8/39

,he tra3c in terms of


9/39


10/39


11/39

De%)*( e#eme(t% 0esign S$eed#

,he design s$eed is the main factor on which designelements

de$ends.

ll Geometric elements such as

i> Radius of the cur%e

ii> Length of the transition cur%e

iii> Rate of su$er ele%ation

i%> E?trawidening of the $a%ement @or Rotar& intersections design s$eed A as follows#

Area Design Speed ,V kmph

Ur!" Ar#!$ 30

R%r!& Ar#!$ 40


12/39

Le(*th of the Tra(%)t)o( "$r+e Length of ,ransition cur%e# length of transition cur%e de$ends u$on

i> Radius of the cur%e

ii> Centrifugal acceleration

Radius of the cur%e B 16 '

C#"(r)*%+!& !,,#r!()" C / 0.5C0.8

D#$)+" $## *r %r!" !r#!$ V/ 30'

C / / 0.76 '$#,

80

75Vm(sec

3

80

7530

3


13/39

Length of the ,ransition cur%e

Ls B

8ere Ls B Length of the ,ransition cur%e m

C B centrifugal acceleration

R B Radius of the circular cur%e m

Ls B B 49.9' m

0.0215V

3

CR

0.0215 303

0.76 16


14/39


15/39

Radius of rotar& roadwa ,he IRC has suggestedthat the

radius of the rotar& to be 2': m and 7:2:m for thes$eed 4 "m$h

and ' "m$h res$ecti%el&.

wea%ing length# the wea%ing o$eration including merging

anddi%erging ta"ing $lace between two channeli5ing islands ofthe ad+acent

intersecting legs then the length of the rotar& roadwa& is"nown as

wea%ing length.

,he wea%ing length should be at least 4 times the width ofthe wea%ing

section.

0esign s$eed wea%ing

length D".$.h>D metres >

4 4:;

' ')


16/39

!idth of wea%ing Section# ,he width of the wea%ing section of the rotar& should be onetra3c lane

D'.:m> wider than the mean entr& width there to.

3.5 '

where e7 is entr& width of the wea%ingsection

e2 is e?it width of the wea%ing section

3.5 '

B 18.7 '

e B

e7 F e22

B9.4 21

2


17/39

Ca$acit& of the Rotar

Ca$acit& of the indi%idual wea%ing sectionsde$ends on factors such as

i. width of the wea%ing sectionii. a%erage width of entr& into the rotar&iii. the wea%ing length andi%. $ro$ortion of wea%ing tra3c.


18/39

,he Ca$acit& of the Rotar& will be calculated #

$ B

eBa%erage entr& width in metres.Di.e. a%erage of He7 and He2>

e(w to be within a range of .4 to 7.

lB length in metres of the wea%ing section between the

ends of channeli5ing islands Dw(l to be within the range .72 and .4> $B$ro$ortion of wea%ing tra3c i.e. ratio of sum of crossing streams

to the total tra3c on the wea%ing section D$BDbFc>(DaFbFcFd>>

range of being .4 to 7..


19/39

$ B

B 4669 %eh(hr.!here

w B 16.5 m

e B 15.2 m

280 16.5 :10.81;:1-0.33;

D 7F.2 >


20/39

S%#r#

is raised with res$ect to theinner edge

thus $ro%iding a trans%erseslo$e

throughout the length of the


21/39

EKuation for design of su$erele%ation is gi%en b&

e F f B

8ere

e B rate of su$erele%ation

f B lateral friction coe3cient

A B s$eed of the %ehicle "m$h

R B Radius of the cur%e m

e B .7:

B 0.30 '

A2

127R

302

127 16


22/39

Radii be&ond which su$erele%ation is not reKuired

Designspeed

(kmph)

Radius (in metres) of transition curve for camber of:

4 > 3 > 2.5 > 2 > 1.7 >

20 50 60 70 90 100

25 70 90 110 140 150

30 100 130 160 200 240

35 140 180 220 270 320

40 180 240 280 350 420

50 280 370 450 550 650

60 470 620 750 950 1100

80 700 950 1100 1400 1700

100 1100 1500 1800 2200 1600


23/39

-a+eme(t o( hor).o(ta#"$r+e

On hori5ontal cur%es it is common $ractice to widen the$a%ement slightl& more than the normal width. ,he ob+ect of$ro%iding e?tra widening are due to the following reasons#

7. oJ trac"ing

i> ,he length of the wheel base of the %ehicle.

ii> the turning angle or radius of the cur%e.

2. ,rans%erse s"idding

'. In case of trailers the& turn the %ehicles on the outer side at

the

beginning of the cur%e.

4. when two %ehicles cross the hori5ontal cur%e there is a$s&chological

tendenc& to maintain greater clearance between the


24/39

E?tra width of $a%ement at hori5ontal cur%es

Radius of

curve, m

Up to 2 2 to ! !" to # #" to " "" to $ Above

$

E?(r!@)( "

&!"# !


25/39

Cha((e#).at)o(

Rotar& Islands are channelised intersections which se$arates

the tra3c

stream in diJerent directions.

It $ro%ides the s$reading of tra3c Mow as far as $ossible the

$oints of

conMict between crossing tra3c streams.

,he number of decisions made b& the dri%er can be reduced

b& allowing

P ) ) # f


26/39

Pr)(")-#e% of -ro-er"ha((e#).e& )(ter%e"t)o(

,he la&out of the intersection should be clearl& %isible sim$le and

understandable b& the dri%er.

La&out of intersection ma"es it necessar& for dri%er not to tra%el in man&

directions. ,his is achie%ed b& %isual guidance islands and mar"ings.

,he island $ro%ided should se$arate highs$eed and turning tra3c

Mows.

,he width of the tra3c lane of straight section without "erb is 3.5 '.

,he width of the tra3c lane near the island is 4.5-5 m at entr& and 6 m at

e?it.


27/39

Rotar' I%#a(&%

Rotar& Islands in circular sha$e for safe tra3c Mow in cloc"wise

direction.

,he cur%e for the tra3c rotaries are

designed b& transition cur%e method.

,he width of rotar& increases de$ending

u$on the %olume of the tra3c Mow.

/)& ) # &


28/39

/)&(e' )%#a(&% "idne& islands are $ro%ided around

central island to slow down the %ehicles

as it comes nearer to the +unction $oint.

It allows the stream of %ehicles to Mow in

single direction without confusion.

,o a%oid fatal accidents.

0$("t)o(% of


29/39

0$("t)o(% oftra(%)t)o( "$r+e

,o introduce graduall& the centrifugal

force between the tangent $oint and the

beginning of the circular cur%e a%oiding

a sudden +er" on the %ehicle.

,o enable the dri%er turn the steeringgraduall& for his own comfort and safet&.

,o enable gradual introduction of the

designed su$er ele%ation and e?tra

widening of $a%ement at the start of the

circular cur%e. ,o im$ro%e the aesthetic a$$earance of

the road.


30/39

Conditions where rotar& is +usti1ed#

ccording to S8,O ha%e suggested that

minimum tra3c %olume is : %ehicles(hour.

ma?imum tra3c %olume is : %ehicles(hour.

Rotar& ma& not function e3cientl& more than :%ehicles(hour.

/ut according to IRC suggestion the $assing of %ehiclesbe '

%ehicles(hour.


31/39

d%antages of Rotar& Intersections#

n orderl& and regimented tra3c Mow is $ro%ided. Indi%idual tra3cmo%ements

are subordinated in fa%or of tra3c as a whole.

ll tra3c $roceeds at a fairl& uniform s$eed. @reKuent sto$$ing andstarting are

a%oided.

!ea%ing re$laces the usual crossing mo%ements at t&$ical atgradeintersection.

0irect conMict is eliminated all tra3c streams merging or di%erting at small

angles. ccident occurring from such mo%ement are usuall& of a minor

natureRotaries are e$icall& suited for intersections with 1%e or more intersectionlegs

though these can also be ado$ted at intersections with ' or 4 legs.

@or moderate tra3c rotaries are selfgo%erning and need no control b& $oliceor

tra3c signals


32/39

Intersections#

Once the rotar& has loc"ed u$ the mo%ement of %ehicles

com$letel& sto$s

and the tra3c will ha%e to be ultimatel& sorted out b& the $olice.

rotar& reKuires a com$arati%el& larger area and ma& not befeasible in

man& built u$ locations.!here $edestrian tra3c is large a rotar& b& itself is not su3cient

to control tra3c and has to be su$$lemented b& tra3c $olice.

!here the angle of intersection between two road is too acute it

becomesdi3cult to $ro%ide adeKuate wea%ing length.

,he $ro%ision of rotaries at close inter%al ma"es tra%eltroublesome.

,ra3c turning right has to tra%el a little e?tra distance.


33/39

0esign $rinci$les

•!ider entries b& narrowing median stri$s or islandsad%anced gi%e

wa& lines

•Smaller central island

•0eMection of tra3c $assing through the roundabout s$eed for

%ehicles

•Sim$le clear and cons$icuous la&out


34/39

Solutions to rotar&

• Re$lace with signali5ed intersection.

•

Install full time signal control on therotar&.

•


35/39

• Recommended geometric modi1cations include

changes toentr&(e?it la&outs circulator& lanes and %isibilit&

$arameters.

• radial format is used with entr&(e?it lanes made$er$endicular rather than tangential to the central

island b&remo%ing Mares and modif&ing s$litter islands.

•

narrowed circulator& lane is used and(or se$aratelanes aremar"ed.

• If enforceable there ma& also be sco$e for the

a$$lication of

C ) f R


36/39

Co(%tr$"t)o( of Rotar')%#a(&% )(+o#e% 1 %ta*e%

7. Earthwor" e?ca%ation for foundation.

2. ACC D1=3=6; for le%eling course.

'. CRS asonr& for Substructure.

4. ACC 20 *r C)"+.

:. Earthwor" e?1lling.

). Groo%e $ointing for CRS.

9. Caution and direction boards.

*. CheKuered tiles.


37/39


38/39

"o("#$%)o(

,ra3c rotaries are introduced for safet& tra3c Mow at the+unction $oint.

Rotaries are designed in circular sha$e for Mow of %ehicles incloc"wise

direction without confusion.

round the rotar& island "idne& islands are $ro%ided to slowdown the

%ehicles near the +unction $oint for a%oiding congestionbetween the

%ehicles. ,he width of the road beside the rotar& island is more. i.e.more than '.:

m.

,he width of the rotar& de$ends u$on the ca$acit& of the Mow.


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Tha(k 'o$

Documents

Design of Rotary