Camber in Road Meaning:
Camber in the road is the transverse slope provided to the road to drain off rainwater from the road surface is known as camber in road.
Camber may be provided in the shape of parabolic, elliptic, or straight-line shape For cement concrete pavement straight line camber is provided while parabolic and elliptic shapes are preferred by fast-moving vehicles because they require the frequent crossing of the crown line during overtaking operation.
It is measured in 1 in ‘n or n% (e.g. 1 in 50 or 2%). advantage of providing camber is quick-drying of pavement which in turn increases safety and subgrade protection by drainage.
The camber of the shoulder should be at least 0.5% steeper than the cross slope of adjoining pavement subjected to a minimum of 3.0% and a maximum value of 5.0%.
The Requirement of The Camber of A Pavement Depends:
(i) Type of pavement surface
(ii) The amount of rainfall
Recommended Values of Camber in Road As Per IRC:
|Type of Road Surface||Camber Limits in Areas of|
|Low Rainfall||Heavy Rainfall|
|High type bituminous surfacing or cement concrete||1 in 60 or 1.7%||1 in 50 or 2.0%|
|Thin bituminous surfacing||1 in 50 or 2.0%||1 in 40 or 2.5%|
|Water bound macadam and gravel pavement||1 in 40 or 2.5%||1 in 33 or 3.0%|
|Earth Road||1 in 33 or 3.0%||1 in 25 or 4.0%|
Types of Camber in Road:
Mainly These Types of Camber We Use In Road Construction,
1. Straight Camber or Sloped
2. Two Straight Line Camber
3. Composite Camber
4. Barrel Camber or Parabolic Camber
1. Straight Camber or Sloped:
This type of camber is provided by meeting two straight surfaces in the crown. The crown is the central and highest point on the road surface.
The edge shape causes inconvenience to traffic, so it is not commonly used.
2. Two Straight Line Camber:
In this, both the straight lines are vertical near the edges and are flattened near the crown. This type of camel is considered best for Indian roads.
3. Composite Camber:
- The composite camber may be composed of a partial parabola and a partial straight line or two straight lines with different slopes.
- Typically, the central part of the road is parabolize and provided with straight slopes near the edges. This helps to reduce the pressure intensity by increasing the contact area of the wheel.
4. Barrel Camber or Parabolic Camber:
It includes a continuous curve, either parabolic or elliptical. This type of camel is ideal for roads used by high-speed vehicles.
Uses of Providing Camber in Road (Purpose):
Quick-drying of pavement which in turn increases safety and subgrade protection by drainage.
Protect the road by preventing surface water from entering the soil below through the pavement.
Camber in the road is used to remove rainwater from the pavement surface as soon as possible and allow the pavement to dry quickly after rain.
Advantages of Camber in Road:
- The camber provides rapid rainwater drainage and thus prevents the foundation course of this road structure from weakening due to the percolation of rainwater to it through the road surface.
- Camber prevents rainwater from accumulating at local narrows or depressions and from forming pools of water around the road surface that are unsightly for the public as well as the road structure.
Disadvantages of Excessive Camber in Road:
- Due to slope in the road transverse tilt of vehicle discomfort the person inside the vehicle.
- the formation of cross ruts or depression.
- The center-line tendency of the vehicle in the movement
NOTE: Gradient provided for pavement is considered as twice of camber.