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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
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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(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
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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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
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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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)
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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(5) (7) (8) (9)Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate R NA NA
NAInadequate R NA NA NA
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate 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
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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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
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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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.
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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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
Maximum RelativeGradient , which is
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
(
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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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
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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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
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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DesignRadius
670700750
800850900950
10001050110011501200
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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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
)
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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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
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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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
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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DesignSpiral
0.4538853
125125125
120110105100959085
NR NR
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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Parameters V (Kmph)VR
(Kmph)emax(%)
f max(%)
Description Design Speed
(80/60/50/40/30) Running SpeedMaximum
Superelevationallowable
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
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
Input Parameters (as
marked ) (%)
Maximum RelativeGradient , which is
dependent on Designspeed V (vide Ex 3-
30)
0.50%
Sl. No. R
(m)ecal(%)
e(%)
f mob
Description Design RadiusCalculated
SuperelevationDesign Superelevation
Mobilised Friction
factor
Formula Designer's choiceV/225R or 4%whichever is less
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
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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(1) (2) (3) (4)
15 Inadequate R Inadequate R Inadequate R
18 Inadequate R Inadequate R Inadequate R
20 Inadequate R Inadequate R Inadequate R
22 Inadequate R Inadequate R Inadequate R
23 Inadequate R Inadequate R Inadequate R 25 Inadequate R Inadequate R Inadequate R 28 Inadequate R Inadequate R Inadequate R 30 Inadequate R Inadequate R Inadequate R 35 Inadequate R Inadequate R Inadequate R 40 Inadequate R Inadequate R Inadequate R 45 Inadequate R Inadequate R Inadequate R 50 Inadequate R Inadequate R Inadequate R 55 Inadequate R Inadequate R Inadequate R
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
100 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
8/11/2019 IRC, AASHTO Design of Geometrics (Hor. & Ver.)
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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
195 Inadequate R Inadequate R Inadequate R 200 Inadequate R Inadequate R Inadequate R 205 Inadequate R Inadequate R Inadequate R 210 Inadequate R Inadequate R Inadequate R 215 Inadequate R Inadequate R Inadequate R 220 Inadequate R Inadequate R Inadequate R 225 Inadequate R Inadequate R Inadequate R 230 Inadequate R Inadequate R Inadequate R 235 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
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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
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Rmin(m)
Minimum Radius to beadopted in design of
H-curve
280
eff (%) based on AASHTO
Maximum EffectiveRelative Gradient,
eff = /b w
0.66%
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
Lr(m)
Minimum DesignRunoff (which dependson e, W and eff ) based
on the equation
Lr = W * e / eff
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.
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)
n Radius (R)Evaluation of
Design RunoffLength (L r )
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(%)
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%
eff (%) based on IRC
Terrain Type
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(5) (7) (8) (9)
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate 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 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 NA
Inadequate 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
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate 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
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Parameters V
(Kmph)VR
(Kmph)emax(%)
f max(%)
Description Design Speed
(80/60/50/40/30) Running SpeedMaximum
Superelevationallowable
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 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
Input Parameters (as
marked ) (%)
Maximum RelativeGradient , which is
dependent on Designspeed V (vide Ex 3-
30)
0.65%
Sl. No. R
(m)ecal(%)
e(%)
f mob
Description Design RadiusCalculated
SuperelevationDesign Superelevation
Mobilised Friction
factor
Formula Designer's choiceV/225R or 4%whichever is less
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
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(1) (2) (3) (4)
15 Inadequate R Inadequate R Inadequate R
18 Inadequate R Inadequate R Inadequate R
20 Inadequate R Inadequate R Inadequate R
22 Inadequate R Inadequate R Inadequate R
23 Inadequate R Inadequate R Inadequate R 25 Inadequate R Inadequate R Inadequate R 28 Inadequate R Inadequate R Inadequate R 30 Inadequate R Inadequate R Inadequate R 35 Inadequate R Inadequate R Inadequate R 40 Inadequate R Inadequate R Inadequate R 45 Inadequate R Inadequate R Inadequate R 50 Inadequate R Inadequate R Inadequate R 55 Inadequate R Inadequate R Inadequate R
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
100 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
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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
240 -6.8% NC 0.102020997245 -7.0% NC 0.100347099250 -7.2% NC 0.098740157255 -7.3% NC 0.097196233260 -7.5% NC 0.09571169265 -7.6% NC 0.094283167270 -7.8% NC 0.092907553275 -7.9% NC 0.091581961280 -8.0% NC 0.090303712
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
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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
385 -9.9% NC 0.071129972390 -10.0% NC 0.07047446395 -10.1% NC 0.069835543400 -10.1% NC 0.069212598405 -10.2% NC 0.068605035410 -10.2% NC 0.068012291415 -10.3% NC 0.06743383420 -10.4% NC 0.066869141425 -10.4% NC 0.06631774
430 -10.5% NC 0.065779161
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Rmin(m)
Minimum Radius to beadopted in design of
H-curve
104
eff (%) based on AASHTO
Maximum EffectiveRelative Gradient,
eff = /b w
0.86%
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
n Radius (R)Evaluation of
Design RunoffLength (L r )
Evaluation of Design Clothoid SpiralLength (L S) for the design controls given
above
Lr(m)
Minimum DesignRunoff (which dependson e, W and eff ) based
on the equation
Lr = W * e / eff
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.
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)
0.67% p 0.64
eff (%) based on IRC
Terrain Type C (m/s 3)
ads
nes the R vs e is correct but L r in (6) and
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%
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(5) (7) (8) (9)
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate R NA NA NA
Inadequate 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 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 NA
Inadequate 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
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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
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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
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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
Input Parameters (as
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
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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
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