Mechanical Extra Widening on a Horizontal Curve for 7m Wide Pavement

Introduction:
Horizontal curves are inevitable in highways and roads. The pavement width required on a horizontal curve depends on the design speed and radius of the curve. The mechanical extra widening is required to compensate for the centrifugal force acting on vehicles while negotiating the curve.

Formula:
The mechanical extra widening required for 7m wide pavement on a horizontal curve of radius R meter is given by L²/2R, where L is the lateral shift required.

Explanation:
The formula for mechanical extra widening is derived based on the centrifugal force acting on the vehicle while negotiating a curve. The centrifugal force is directly proportional to the square of the speed and inversely proportional to the radius of the curve. To maintain a safe speed, the driver needs to apply a force to counteract the centrifugal force, which increases with the square of the speed.

To provide sufficient space for the driver to apply the necessary force, the pavement width needs to be increased. The mechanical extra widening compensates for the lateral shift required to provide sufficient space for the driver to apply the necessary force to counteract the centrifugal force.

The lateral shift required depends on the design speed and radius of the curve. For a 7m wide pavement, the lateral shift required is given by the formula L²/2R.

Conclusion:
The mechanical extra widening required for a 7m wide pavement on a horizontal curve of radius R meter is given by L²/2R. This formula helps to determine the required pavement width to provide sufficient space for the driver to apply the necessary force to negotiate the curve safely.