Widening of Pavement on Horizontal Curves | Extra Widening Of Pavement On Curve Road| Widening of Pavement on Horizontal Curves of Non Urbon roads
Widening of Pavement on Horizontal Curves | Extra Widening Of Pavement On Curve Road| Widening of Pavement on Horizontal Curves of Non Urbon roads
INTRODUCTION :
Widening of Pavement on Horizontal Curves:
When a vehicle takes a turn to negotiate a horizontal curve, the rear wheels do not follow the same path as that of the front wheels. Normally the rear wheels follow the inner path on the curve as compared with front wheels.
The vehicle has occupies more width that it occupies on straight portion of the road. To compensate this, the carriageway width increased on the entire curved portion of the road, which is called extra widening of pavement on curve.
The formula of Extra widening:
Extra width = Mechanical widening + Psychological widening
We = Wn + Wpc
nl2 V∗
We =
2R + 9.5√R
n = Number of traffic lanes
l = Length of wheel base (m) (normally
6.1 m or 6.0 m)
R = Radius of horizontal curve (m)
V∗ = Design
speed (km/h)
Table : Recommended Extra Width of pavement at horizontal curves
|
Radius of Curve (m) |
< 20 |
20 – 40 |
41 – 60 |
61 – 100 |
101 – 300 |
> 300 |
|
Extra
width on two- lane pavement (m) |
1.5 |
1.5 |
1.2 |
0.9 |
0.6 |
Nil |
|
Extra
width on single lane pavement (m) |
0.9 |
0.6 |
0.6 |
Nil |
Nil |
Nil |
Note: For multi-lane roads, the pavement
widening is calculated by adding half the extra width of two-lane roads to each
lane of multi-lane road
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