irc, aashto design of geometrics (hor. & ver.)

8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)

1/35

Parameters V (Kmph)VR

(Kmph)emax (%)

f max(%)

Description Design Speed

(120/100/80/65/60/50/40)

RunningSpeed

MaximumSuperelevation

allowable

Maximum radialfriction factor that can

be mobilised

Formula/Reference

The designer has tochoose based on thetype of road facility

Exhibit 3-14 ofGreen Book

2004

The designer has tochoose based on the

terrain, rainfall,snowfall, amount oflow speed traffic, etc

IRC: 73 assumes constant

f max (=0.15) irrespective ofthe Design Speed. However,

it is better based on IRCGuidelines for

Expressway/AASHTO .

Values 100 85 7.0% 0.11

Input Parameters (as

marked ) (%)

Maximum RelativeGradient , which is

dependent on Designspeed V (vide Ex 3-

30)

0.44%

Sl. No. R

(m)ecal(%)

e (%) f mob

Description Design Radius

Calculated

Superelevation

Design

Superelevation

Mobilised Friction

factor

Formula Designer's choiceV/225R or 7%whichever is less

IRC Horizontal Geometry Design for Rural (Open

* (Strictly speaking, up to 2 lanes carriageway this design is alright, however, for more thaand Design L s in (9) are incorrect

Evaluation of Design Superelevation (e) vis--vis given De

W (m)

Width of Roadway rotated as a plane section (it includes

carriageway lanes and pavedshoulder, if any, with same cross

slope as the lanes.

7

bw

Adjustment factor for number ofequivalent lanes (say, n 1=W/3.6) rotated as

a plane section (vide Exihit 3-31), bw={(1+0.5(n 1-1)}/n 1

0.757142857


2/35

(1) (2) (3) (4)

60 Inadequate R Inadequate R Inadequate R 80 Inadequate R Inadequate R Inadequate R 90 Inadequate R Inadequate R Inadequate R

100 Inadequate R Inadequate R Inadequate R

120 Inadequate R Inadequate R Inadequate R 140 Inadequate R Inadequate R Inadequate R 150 Inadequate R Inadequate R Inadequate R 160 Inadequate R Inadequate R Inadequate R 200 Inadequate R Inadequate R Inadequate R 250 Inadequate R Inadequate R Inadequate R 260 Inadequate R Inadequate R Inadequate R 300 Inadequate R Inadequate R Inadequate R 350 Inadequate R Inadequate R Inadequate R

400Inadequate R Inadequate R Inadequate R

440 10.10% 7.0% 0.1090

450 9.88% 7.0% 0.1050

500 8.89% 7.0% 0.0875550 8.08% 7.0% 0.0732600 7.41% 7.0% 0.0612650 6.84% 6.8% 0.0528670 6.63% 6.6% 0.0512700 6.35% 6.3% 0.0490750 5.93% 5.9% 0.0457800 5.56% 5.6% 0.0429850 5.23% 5.2% 0.0403900 4.94% 4.9% 0.0381950 4.68% 4.7% 0.0361

1000 4.44% 4.4% 0.0343

1050 4.23% 4.2% 0.03271100 4.04% 4.0% 0.03121150 3.86% 3.9% 0.02981200 3.70% 3.7% 0.02861250 3.56% 3.6% 0.02741300 3.42% 3.4% 0.02641350 3.29% 3.3% 0.0254

1400 3.17% 3.2% 0.0245

1450 3.07% 3.1% 0.02371500 2.96% 3.0% 0.02291550 2.87% 2.9% 0.0221


3/35

1600 2.78% 2.8% 0.02141650 2.69% 2.7% 0.02081700 2.61% 2.6% 0.02021750 2.54% 2.5% 0.01961800 2.47% 2.5% 0.0191

18502.40% 2.4% 0.0185

1900 2.34% 2.3% 0.01811950 2.28% 2.3% 0.01762000 2.22% 2.2% 0.01712050 2.17% 2.2% 0.01672100 2.12% 2.1% 0.01632150 2.07% 2.1% 0.01602200 2.02% 2.0% 0.01562250 1.98% NC 0.05502300 1.93% NC 0.05422350 1.89% NC 0.05352400 1.85% NC 0.05282450 1.81% NC 0.05212500 1.78% NC 0.05152550 1.74% NC 0.05092600 1.71% NC 0.05032650 1.68% NC 0.04972700 1.65% NC 0.04922750 1.62% NC 0.04862800 1.59% NC 0.04812850 1.56% NC 0.04762900 1.53% NC 0.04722950 1.51% NC 0.04673000 1.48% NC 0.04623050 1.46% NC 0.04583100 1.43% NC 0.04543150 1.41% NC 0.04503200 1.39% NC 0.0446

3250 1.37% NC 0.04423300 1.35% NC 0.04393350 1.33% NC 0.0435


4/35


5/35

Rmin(m)

Minimum Radius to beadopted in design of

H-curve

438

eff (%) based on AASHTO

Maximum EffectiveRelative Gradient,

eff = /b w

0.58%

1 in 172

Vcheck(Kmph)

LS(m)

LS(m)

DesignLS (m)

Check for Speed (basedon e and f max), However,

this is not correct, asf max is not going to bemobilised for all radii.

Clothoid Length(based onallowable

introduction ofRadial

Acceleration ( C)

ClothoidLength

()

2.7*V 2/R forPlain or

Rolling, V 2/Rfor

Mountaneousor Steep

Maximum of thevalues among

(6) and (7)rounded up tomultiple of 5

Highways

2 lanes the R vs e is correct but L r in (6)

c(%)

Normal Cross Slope(NC) / Camber

The designer has tochoose the CS/Camber

based on the road surfacetype and rainfall intensity(vide table 5 of IRC: 38)

2.0%

Evaluation of

Design RunoffLength (L r )

0.67%

eff (%) based on IRC

Maximum EffectiveRelative Gradient, eff = 1 in 150 , for

Plain or Rolling terrain,and = 1 in 60 for

Mountainous or steep.

Terrain should be one of thefollowing, Plain (P) or

Rolling ( R) or Mountainous(M) or Steep (S). Enter the

letter in the parenthesis asappropriate.

p

ign Radius (R)Evaluation of Design Clothoid Spiral

Length (L S) for the design controls givenabove

C (m/s 3)

Rate of change of Radialacceleration, which is derived bythe formula, C=80/(75+V), in no

case it should lie beyond (0.5,0.8)

0.5

Terrain Type

1 in 150

Minimum DesignRunoff (which dependson e, W and eff ) based

on the equation

Lr = W * e / eff

Lr(m)


6/35

(5) (7) (8) (9)Inadequate R NA NA NA

Inadequate R NA NA NA



Inadequate R NA NA

NAInadequate R NA NA NA









100.2915749 98 61 100

101.424849 96 60 100

106.9111781 86 54 90

112.1293895 79 49 80

117.1153278 72 45 75

121.3463821 67 42 75

122.492222 65 40 75

124.1911609 62 39 70

126.9722192 58 36 65

129.6936561 54 34 60

132.3591495 51 32 60

134.9720136 48 30 55

137.535248 46 28 55

140.0515778 43 27 50

142.5234873 41 26 45

144.9532492 40 25 45

147.3429484 38 23 45

149.6945037 36 23 40

152.0096854 35 22 40

154.2901307 34 21 40

156.537358 32 20 40

158.7527778 31 19 40

160.9377036 30 19 35

163.0933611 29 18 35

165.2208959 28 17 35

NA

NA

NA

NA

36

33

33

33

57

72

54

51

48

45

45

42

39

39

36

36

NA

75

75

75

75

72

69

63

60

( L r

) . W h e r e , S

p i r a

l C u r v e

i s n o

t r e q u i r e

d , t h e

R u n - o

f f L e n g t

h s h o u

l d b e u s e d , a s

g i v e n

i n c o

l u m n

( 6 ) .

75

NA

NA

NA

NA

NA

(6)

NA

NA

NA

NA


7/35

167.3213807 27 17 30

169.3958218 27 16 30

171.4451645 26 16 30

173.4702985 25 15 NR

175.4720617 24 15 NR

177.4512453 24 15 NR

179.4085964 23 14 NR

181.3448219 23 14 NR

183.2605916 22 14 NR

185.1565404 21 13 NR

187.033271 21 13 NR

188.8913562 20 13 NR

190.731341 20 12 NR

160.3667671 NR NR NR

162.1388294 NR NR NR

163.8917326 NR NR NR

165.6260849 NR NR NR

167.3424632 NR NR NR

169.041415 NR NR NR

170.7234606 NR NR NR

172.3890948 NR NR NR

174.0387888 NR NR NR

175.6729917 NR NR NR

177.2921318 NR NR NR

178.8966182 NR NR NR

180.4868416 NR NR NR

182.0631758 NR NR NR

183.6259786 NR NR NR

185.1755923 NR NR NR

186.7123456 NR NR NR

188.2365533 NR NR NR

189.7485178 NR NR NR

191.2485294 NR NR NR

192.7368673 NR NR NR

194.2137997 NR NR NR

195.679585 NR NR NR

NR

NR

NR

24

30

27

27

27

27

24

24

30

NR

24

24

24

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

30

NR

NR

NR

W h e r e e v e r

S p i r a l

C u r v e

i s p r o v

i d e d , i

t s l e n g

t h ( L

S ) i s a l s o e q u a

l t o t h e

R u n - o

f f L e n g t

h

NR

NR

NR


8/35

It is considered that Spiral Transition is not required for "Those radii" for which the "Radial Acceleration (V 2/13R)" becomes less than 0.45 m/s 2, asthe corresponding sideway jerk is so less that the traffic can comfortablyadjust when they directly enter into a Circular Curve from TangentAlignment. Reference can be drawn from page 187 of AASHTO 2004.Where Spiral is absent, of the Run-off is to be provided on Tangent

and remaining would be on the Circular Curve.


9/35

Parameters V

(Kmph)VR

(Kmph)emax(%)

f max(%)

Rmin(m)

R PI(m)

Description Design SpeedRunning

Speed

Maximumsuperelevation

allowable

Maximum

radialfrictionfactor that

can bemobilised

MinimumRadius to beadopted in

design of H-curve

Vide Exhibit3-18

Formula/Reference

The designerhas to choose based on thetype of road

facility

Exhibit 3-14 ofGreen Book

2004

The designerhas to choose based on the

terrain,rainfall,

snowfall, etc

Exhibit 3-12(or 3-15) ofGreen Book

2004

Values 100 85 7.0% 0.12 414 813

InputParameters (as

marked )

R(m) f (e+f)

e(%)

a cu a on o es gn p ra urve eng S an


dependent on Design speedV (vide Ex 3-30)

MaximuRelative Gra is derived b

(vide E

eff =

Evaluation of Design Friction Factor (f), andconsequently the Design Superelevation (e) vis--vis

given Design Radius (R)

0.725

W (m)

Width of Roadway rotated as a plane section (it includes

carriageway lanes and paved

shoulder, if any, with same crosslope as the lanes

EvaluationRunoff L

8

(%)

0.44%

eff

0.6

bwAdjustment factor for

number of equivalent lanes(say, n 1=W/3.6) rotated asa plane section (vide Exihit

3-31), b w={(1+0.5(n 1-1)}/n 1

(


10/35

Description Design RadiusDesign Friction

factor

Design valueof summation

ofSuperelevation and Friction

factor

DesignSuperelevati

on

Formula Designer's

choice

C a s e

1 ( w h e n

R < R P

I ) ,

f = h P

I +

S 2 { ( 1 / R ) - ( 1 / R

P I ) } + M O * [ { ( 1 / R m

i n )

- ( 1 / R ) } / L

2 ] 2

C a s e

2 ( w h e n

R

R P I ) , f

= M O * ( R P

I / R ) 2 + ( S

1 / R )

(e+f) - f

(1) (2) (3) (4)400 NA NA

420 0.117489163 0.1874766 7.0%

450 0.105424551 0.1749781 7.0%

500 0.089572457 0.1574803 6.8%

550 0.077503622 0.1431639 6.6%

600 0.068065737 0.1312336 6.3%

650 0.0605197 0.1211387 6.1%

700 0.054372592 0.1124859 5.8%

750 0.04928472 0.1049869 5.6%800 0.045015357 0.0984252 5.3%

850 0.041387016 0.0926355 5.1%

900 0.038264986 0.0874891 4.9%950 0.035553638 0.0828844 4.7%

1000 0.033179678 0.0787402 4.6%1050 0.031085894 0.0749906 4.4%1100 0.029227039 0.071582 4.2%1150 0.027566909 0.0684697 4.1%1200 0.02607622 0.0656168 4.0%1250 0.024731057 0.0629921 3.8%1300 0.023511714 0.0605694 3.7%1350 0.022401819 0.058326 3.6%1400 0.021387671 0.056243 3.5%1450 0.02045772 0.0543036 3.4%1500 0.019602167 0.0524934 3.3%1550 0.018812651 0.0508001 3.2%1600 0.018081998 0.0492126 3.1%

4

4

4

55

4

4

4

6

6

5

5

5

(

9

9

9

8

8

8

7

7

7

6

6

6

MinimuRunoff (whon e, W and

on the e

Lr = W


11/35

1650 0.017404016 0.0477213 3.0%1700 0.01677334 0.0463177 3.0%1750 0.016185297 0.0449944 2.9%1800 0.0156358 0.0437445 2.8%1850 0.01512126 0.0425622 2.7%1900 0.014638513 0.0414422 2.7%

1950 0.014184761 0.0403796 2.6%2000 0.013757518 0.0393701 2.6%2050 0.013354573 0.0384098 2.5%2100 0.012973948 0.0374953 2.5%2150 0.012613874 0.0366233 2.4%2200 0.012272758 0.035791 2.4%2250 0.011949169 0.0349956 2.3%2300 0.011641813 0.0342349 2.3%2350 0.011349517 0.0335064 2.2%2400 0.01107122 0.0328084 2.2%

2450 0.010805956 0.0321388 2.1%2500 0.010552843 0.0314961 2.1%2550 0.010311079 0.0308785 2.1%2600 0.010079927 0.0302847 2.0%2650 0.009858715 0.0297133 2.0%2700 0.009646824 0.029163 2.0%2750 0.009443685 0.0286328 1.9%2800 0.009248774 0.0281215 1.9%2850 0.009061607 0.0276281 1.9%2900 0.008881739 0.0271518 1.8%

2950 0.008708756 0.0266916 1.8%3000 0.008542274 0.0262467 1.8%3050 0.008381939 0.0258164 1.7%3100 0.00822742 0.0254001 1.7%3150 0.00807841 0.0249969 1.7%3200 0.007934623 0.0246063 1.7%3250 0.007795793 0.0242277 1.6%3300 0.00766167 0.0238607 1.6%3350 0.007532021 0.0235045 1.6%3400 0.007406628 0.0231589 1.6%3450 0.007285288 0.0228232 1.6%3500 0.007167809 0.0224972 1.5%

3

3

2

2

2

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

4

3

2

2

2

2

2

2

2

2

2

2

2

2

It is considered that Spiral Transition is not required for radii more than 1700 m for the set ofconsideration is based on the premise that on the tangent alignment maximum superelevation asuperelevation of 3% for R=1700). Incidentally, for the set of design criteria and the minimumgives rise to a Radial Acceleration =0.45 m/s 2 which is much below the comfort value specieof the Run-off is to be provided on Tangent and remaining would be on the circular curve.

2

2

2

2


12/35

DesignRadius

670700750

800850900950

10001050110011501200


13/35

hPI(m)

S1(%)

S2(%)

L1(Curvature)

L2(Curvature)

MO(m)

Vide Exhibit3-18

Slope of thef

distributioncurve at

Radius=

Slope of the fdistributioncurve at

Radius=R min

Vide Exhibit 318

Vide Exhibit3-18

Middle

Ordinate of thef distribution

curve(unsymmetrica

l parabola)

Exhibit 3-18and page

160 ofAASHTO

2004( S1=h PI *

R PI )

Page 160S2 = (f max-

hPI) /[(1/Rmin) -

(1/R PI)]

L1=1/R PIL2=1/R min -

1/R PI

[L1*L2*(S2-S1)] /[2*(L1+L

2)]

0.02689 21.85039 78.74016 0.00123 0.00118 0.01715

LS(m)

LS,min(m)

LS,max(m)

DesignLS (m)

es gn upere eva on uno r

Effectivedient, whichthe formula

x 3-31)

/b w

Evaluation of Design Clothoid Spiral Length(L S) for the design controls given above

of Designngth (L r)

(%)

%

r

)


14/35

ClothoidLength

(based onallowable

introductionof Radial

Acceleration, C= 0.5

m/s3)

ClothoidLength

(based onminimum

shift(Smin)=0.2 m.)

ClothoidLength

(based onmaximum shift(Smax)=1.0 m.)

0.0215* V

/(R*C)Refer

equation 3-29 of

AASTHO,2004

(24*R*S min

) Refer

equation 3-28of AASTHO,

2004

(24*R*Sma

x)

Referequation 3-30of AASTHO,

2004

Based oncolumn (6), but in no

casegreaterthan thevalues in

column (8)

(6) (7) (8) (9)NA

103 45 100 11096 46 104 10086 49 110 10079 51 115 9572 54 120 9067 56 125 8562 58 130 85

58 60 134 8054 62 139 7551 64 143 7548 66 147 7046 68 151 7043 69 155 6541 71 159 6540 73 162 6038 74 166 6036 76 170 6035 77 173 5534 79 177 5532 80 180 5531 82 183 5030 83 187 5029 85 190 5028 86 193 4527 88 196 45

5

5

2

11

8

8

5

3

0

7

4

4

)

3

3

0

7

4

1

8

5

2

9

6

3

Designich depends eff ) based

quation

e / eff


15/35

27 89 199 4526 90 202 4525 92 205 NR 24 93 208 NR 24 94 211 NR 23 95 214 NR

23 97 216 NR 22 98 219 NR 21 99 222 NR 21 100 224 NR 20 102 227 NR 20 103 230 NR 20 104 232 NR 19 105 235 NR 19 106 237 NR 18 107 240 NR 18

108 242 NR 18 110 245 NR 17 111 247 NR 17 112 250 NR 17 113 252 NR 16 114 255 NR 16 115 257 NR 16 116 259 NR 16 117 262 NR 15 118 264 NR 15

119 266 NR 15 120 268 NR 15 121 271 NR 14 122 273 NR 14 123 275 NR 14 124 277 NR 14 125 279 NR 14 126 281 NR 13 127 284 NR 13 128 286 NR 13 129 288 NR 13 130 290 NR

0

0

7

7

7

3

0

0

0

0

6

6

3

3

3

9

9

9

6

6

2

9

7

7

7

4

4

4

4

4

4

4

4

7

esign criteria (namely, Speed 100 Kmph, e max=7.0%). Thisllowed is limited to 2.0% (which is of the designRadius (here 1700 m) beyond which Spiral is not requiredd in page 187 of AASHTO 2004. Where Spiral is absent,

1

1

1

4


16/35

DesignSpiral

0.4538853

125125125

120110105100959085

NR NR


17/35

Parameters V (Kmph)VR

(Kmph)emax(%)

f max(%)


(80/60/50/40/30) Running SpeedMaximum

Superelevationallowable


be mobilised

Formula/Reference


Exhibit 3-14 ofGreen Book 2004

choose based on the

terrain, rainfall,snowfall, amount of low

speed traffic, etc(Desirably limited to

IRC: 73 assumesconstant f max (=0.15)

irrespective of theDesign Speed.

However, it is better based on AASHTO .

Values 80 70 4.0% 0.14


marked ) (%)



30)

0.50%

Sl. No. R

(m)ecal(%)

e(%)

f mob

Description Design RadiusCalculated

SuperelevationDesign Superelevation

Mobilised Friction

factor


Evaluation of Design Superelevation (e) vis--vis given Desig

7 0.757142857

Width of Roadway rotated as a planesection (it includes carriageway lanesand paved shoulder, if any, with same

cross slope as the lanes

Adjustment factor for number of equivalentlanes (say, n 1=W/3.6) rotated as a plane

section (vide Exihit 3-31), b w={(1+0.5(n 1-1)}/n 1

IRC Horizontal Geometry Design for Urban Ro

* (Strictly speaking, up to 2 lanes carriageway this design is alright, however, for more than 2 lDesign L s in (9) are incorrect

W (m) bw


18/35

(1) (2) (3) (4)






60 Inadequate R Inadequate R Inadequate R 65 Inadequate R Inadequate R Inadequate R 70 Inadequate R Inadequate R Inadequate R 75 Inadequate R Inadequate R Inadequate R 80 Inadequate R Inadequate R Inadequate R 86 Inadequate R Inadequate R Inadequate R 90 Inadequate R Inadequate R Inadequate R 95 Inadequate R Inadequate R Inadequate R


105 Inadequate R Inadequate R Inadequate R 110 Inadequate R Inadequate R Inadequate R 115 Inadequate R Inadequate R Inadequate R 120 Inadequate R Inadequate R Inadequate R 125 Inadequate R Inadequate R Inadequate R 130 Inadequate R Inadequate R Inadequate R 135 Inadequate R Inadequate R Inadequate R 140 Inadequate R Inadequate R Inadequate R 145 Inadequate R Inadequate R Inadequate R 149 Inadequate R Inadequate R Inadequate R 150 Inadequate R Inadequate R Inadequate R 155 Inadequate R Inadequate R Inadequate R

160 Inadequate R Inadequate R Inadequate R 165 Inadequate R Inadequate R Inadequate R 170 Inadequate R Inadequate R Inadequate R 175 Inadequate R Inadequate R Inadequate R


19/35

180 Inadequate R Inadequate R Inadequate R 183 Inadequate R Inadequate R Inadequate R 185 Inadequate R Inadequate R Inadequate R 189 Inadequate R Inadequate R Inadequate R 190 Inadequate R Inadequate R Inadequate R


240 Inadequate R Inadequate R Inadequate R 245 Inadequate R Inadequate R Inadequate R 250 Inadequate R Inadequate R Inadequate R 255 Inadequate R Inadequate R Inadequate R 260 Inadequate R Inadequate R Inadequate R 265 Inadequate R Inadequate R Inadequate R 270 Inadequate R Inadequate R Inadequate R 275 Inadequate R Inadequate R Inadequate R 280 4.0% 4.0% 0.139977503

285 3.7% 3.7% 0.139820003290 3.4% 3.4% 0.139771382295 3.1% 3.1% 0.139826104300 2.8% 2.8% 0.139979003305 2.6% 2.6% 0.139225248310 2.3% 2.3% 0.139560325315 2.0% 2.0% 0.139980002320 1.8% 2.0% 0.137480315325 1.6% 2.0% 0.135057541330 1.3% 2.0% 0.132708184335 1.1% 2.0% 0.130428958340 0.9% 2.0% 0.128216767345 0.7% 2.0% 0.126068698350 0.4% 2.0% 0.123982002355 0.2% 2.0% 0.121954087


20/35

360 -0.1% 2.0% 0.119982502365 -0.2% 2.0% 0.118064934370 -0.4% 2.0% 0.116199191375 -0.6% 2.0% 0.114383202380 -0.8% 2.0% 0.112615002

385 -1.0% 2.0% 0.110892729390 -1.1% 2.0% 0.109214617395 -1.3% 2.0% 0.107578989400 -1.5% 2.0% 0.105984252405 -1.6% 2.0% 0.104428891410 -1.8% 2.0% 0.102911465415 -1.9% 2.0% 0.101430604420 -2.1% NC 0.139985002425 -2.2% NC 0.138573414

430 -2.3% NC 0.137194653


21/35

Rmin(m)


H-curve

280



eff = /b w

0.66%

Vcheck(Kmph)

LS(m)

LS(m)

DesignLS (m)





Acceleration ( C)

ClothoidLength

()


Rolling, V 2/Rfor

Mountaneousor Steep



Lr(m)


on the equation

Lr = W * e / eff









n Radius (R)Evaluation of


Evaluation of Design Clothoid SpiralLength (L S) for the design controls given

above

0.67% p 0.516129032

C (m/s 3)

ads

nes the R vs e is correct but L r in (6) and

c(%)




2.0%


Terrain Type


22/35

(5) (7) (8) (9)





Inadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NA

Inadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NA



Inadequate R NA NA

NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NA







NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NA

NANA

NA

NA

NA

NA

NA

NA

NA

W h e r e e v e r

S p i r a l

C u r v e

i s p r o v

i d e d , i

t s l e n g

t h ( L

S ) i s a l s o e q u a l

t o t h e

R u n - o

f f L e n g t

h ( L

r ) . W h e r e , S

p i r a

l C u r

(6)

NA

NA

NA

NA

NA

NA

NA

NA

NANA

NA

NA

NA

NA

NA

NA

NA

NA


23/35


24/35


25/35

Parameters V

(Kmph)VR

(Kmph)emax(%)

f max(%)


(80/60/50/40/30) Running SpeedMaximum

Superelevationallowable


be mobilised

Formula/Reference


Exhibit 3-14 ofGreen Book 2004

The designer has to choose based on the terrain,

rainfall, snowfall, amountof low speed traffic, etc(Desirably limited to

4.0%)

Based on IRC: 86,f max=0.15 irrespective

of V. The same isfollowed except for

V=80 Kph, for whichfmax =0.14

Values 50 47 4.0% 0.15


marked ) (%)



30)

0.65%

Sl. No. R

(m)ecal(%)

e(%)

f mob

Description Design RadiusCalculated

SuperelevationDesign Superelevation

Mobilised Friction

factor


Evaluation of Design Superelevation (e) vis--vis given Desig

Width of Roadway rotated as a planesection (it includes carriageway lanesand paved shoulder, if any, with same

cross slope as the lanes

Adjustment factor for number of equivalentlanes (say, n 1=W/3.6) rotated as a plane

section (vide Exihit 3-31), b w={(1+0.5(n 1-1)}/n 1

7 0.757142857

W (m) bw

IRC Horizontal Geometry Design for Urban Ro

* (Strictly speaking, up to 2 lanes carriageway this design is alright, however, for more than 2 lDesign L s in (9) are incorrect


26/35

(1) (2) (3) (4)






60 Inadequate R Inadequate R Inadequate R 65 Inadequate R Inadequate R Inadequate R 70 Inadequate R Inadequate R Inadequate R 75 Inadequate R Inadequate R Inadequate R 80 Inadequate R Inadequate R Inadequate R 86 Inadequate R Inadequate R Inadequate R 90 Inadequate R Inadequate R Inadequate R 95 Inadequate R Inadequate R Inadequate R


105 3.8% 3.8% 0.149476565110 2.9% 2.9% 0.149954903115 2.2% 2.2% 0.149174255120 1.5% 2.0% 0.144041995125 0.8% 2.0% 0.137480315130 0.2% 2.0% 0.13142338135 -0.5% 2.0% 0.125815106140 -1.0% 2.0% 0.120607424145 -1.5% 2.0% 0.115758892149 -1.8% 2.0% 0.112114358150 -1.9% 2.0% 0.111233596155 -2.3% NC 0.147000254

160 -2.7% NC 0.143031496165 -3.1% NC 0.139303269170 -3.5% NC 0.135794349175 -3.8% NC 0.132485939


27/35

180 -4.1% NC 0.12936133183 -4.3% NC 0.127568521185 -4.4% NC 0.126405618189 -4.6% NC 0.124153647190 -4.7% NC 0.12360547

195 -5.0% NC 0.12094892200 -5.2% NC 0.118425197205 -5.4% NC 0.116024582210 -5.7% NC 0.113738283215 -5.9% NC 0.111558323220 -6.1% NC 0.109477452225 -6.3% NC 0.107489064230 -6.5% NC 0.105587128235 -6.7% NC 0.103766125


285 -8.1% NC 0.089070314290 -8.3% NC 0.087879446295 -8.4% NC 0.086728947300 -8.5% NC 0.085616798305 -8.6% NC 0.084541113310 -8.7% NC 0.083500127315 -8.8% NC 0.082492188320 -8.9% NC 0.081515748325 -9.0% NC 0.080569352330 -9.1% NC 0.079651634335 -9.2% NC 0.078761312340 -9.3% NC 0.077897175345 -9.3% NC 0.077058085350 -9.4% NC 0.07624297355 -9.5% NC 0.075450815


28/35

360 -9.6% NC 0.074680665365 -9.7% NC 0.073931615370 -9.7% NC 0.073202809375 -9.8% NC 0.072493438380 -9.9% NC 0.071802735


430 -10.5% NC 0.065779161


29/35

Rmin(m)


H-curve

104



eff = /b w

0.86%

Vcheck(Kmph)

LS(m)

LS(m)

DesignLS (m)





Acceleration ( C)

ClothoidLength

()


Rolling, V 2/Rfor

Mountaneousor Steep



n Radius (R)Evaluation of


Evaluation of Design Clothoid SpiralLength (L S) for the design controls given

above

Lr(m)


on the equation

Lr = W * e / eff









0.67% p 0.64


Terrain Type C (m/s 3)

ads

nes the R vs e is correct but L r in (6) and

c(%)




2.0%


30/35

(5) (7) (8) (9)





Inadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NA

Inadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NAInadequate R NA NA NA



50.06975135 4065

4550.0062996 39 62 40

50.12045491 37 59 4050.89990177 35 57 3551.9494947 34 54 35

52.97829744 33 52 3553.98749855 32 50 3554.97817749 30 49 3055.95131813 29 47 3056.71781025 29 46 30

56.9078202 28 45 30

50.58705368 NR NR NR

51.39649794 NR NR NR

52.19339039 NR NR NR

52.97829744 NR NR NR

53.75174416 NR NR NR

NR

NR

NR

21

21

21

21

NR

NR

33

24

21

21

21

21

NA

NA

NA

42

NA

NA

NANA

NA

NA

W h e r e e v e r

S p i r a l

C u r v e

i s p r o v

i d e d , i

t s l e n g

t h ( L

S ) i s a l s o e q u a l

t o t h e

R u n - o

f f L e n g t

h ( L

r ) . W h e r e , S

p i r a

l C u r

(6)

NA

NA

NANA

NANA

NA

NA

NA

NA

NA

NA

NA


31/35

54.51421833 NR NR NR

54.96662624 NR NR NR

55.2661741 NR NR NR

55.86045113 NR NR NR

56.00803514 NR NR NR

56.74019739 NR NR NR 57.46303159 NR NR NR

58.17688544 NR NR NR

58.88208556 NR NR NR

59.57893923 NR NR NR

60.26773598 NR NR NR

60.94874896 NR NR NR

61.62223625 NR NR NR

62.28844195 NR NR NR

62.94759725 NR NR NR 63.59992138 NR NR NR

64.24562242 NR NR NR

64.88489809 NR NR NR

65.51793648 NR NR NR

66.14491666 NR NR NR

66.76600932 NR NR NR

67.38137725 NR NR NR

67.9911759 NR NR NR

68.59555379 NR NR NR 69.19465297 NR NR NR

69.78860939 NR NR NR

70.37755324 NR NR NR

70.96160934 NR NR NR

71.54089739 NR NR NR

72.11553231 NR NR NR

72.68562444 NR NR NR

73.25127985 NR NR NR

73.81260055 NR NR NR

74.36968468 NR NR NR

74.92262676 NR NR NR

75.47151781 NR NR NR

76.01644559 NR NR NR

76.55749473 NR NR NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR NR

NR

NR

NR

NR

NR


32/35

77.0947469 NR NR NR

77.62828093 NR NR NR

78.15817296 NR NR NR

78.68449657 NR NR NR

79.20732289 NR NR NR

79.72672074 NR NR NR 80.24275668 NR NR NR

80.75549517 NR NR NR

81.26499862 NR NR NR

81.77132749 NR NR NR

82.27454041 NR NR NR

82.7746942 NR NR NR

83.27184398 NR NR NR

83.76604324 NR NR NR

84.25734389 NR NR NR

NR

NR

It is considered that Spiral Transition is not required for "Those radii" for which the "Radial Acceleration (V 2/13R)" becomes less than 0.45 m/s 2, asthe corresponding sideway jerk is so less that the traffic can comfortablyadjust when they directly enter into a Circular Curve from TangentAlignment. Reference can be drawn from page 187 of AASHTO 2004.Where Spiral is absent, of the Run-off is to be provided on Tangent

and remaining would be on the Circular Curve.

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR

NR NR

NR


33/35

Parameters Standard of DesignV

(Kmph)eff (%)

Description AASHTO or IRC (A/I) Design SpeedMaximum Effective Relative

Gradient provided

Formula/Reference

The input must be eitherAASHTO, A, IRC, I

The designer has tochoose based on thetype of road facility(120.100,80,65,60,5

0,40,35,30,25,20)

Values i 100 0.67


marked )

Parameters S

(m)A

Vertical Curve Type(Crest / Sag)

Description Stopping Sight Distance (SSD) Grade Difference

Values 180 2.50 Crest

c

The input must be either

'Crest, C, Sag, S

AASHTO/IR

Formula

/Reference

S = 0.278Vt + V2/254 f wheret=2.5 sec and f = 0.35

G1-G2If A>0, Crest CurveIf A


34/35

Guidance for Gradient (G%)G1(%)

G2(%)

This Guidance for G-value should be applied onlyon Horizontal Curve (Run-out & Run-off) stretch

to ensure adequate drainage Approach Grade Departure Grade

Two controls/criteria to be followed simultaneously.(1) The gradient of the PGL should be at least 0.5%(2) The gradient of the Road edges should be at least0.2% (for uncurbed road) and at least 0.5% (for curbedroad)

The designer to choose based on the terrain andamount of Truck/Heavy

vehicle population(Upgrade +ve,

Downgrade -Ve)

The designer to choose based on the terrain andamount of Truck/Heavy

vehicle population(Upgrade +ve, Downgrade

Ve)

For Upgrade, G >= 0.87For Downgrade, G =0.87%, G


35/35

irc, aashto design of geometrics (hor. & ver.)

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