Superelevation and Rotation of Pavement

Superelevation is the banking of roadways on curves to counteract the centrifugal force acting on the vehicles. It is achieved by raising the outer edge of the pavement relative to the inner edge. Rotation of pavement is a method of achieving superelevation by rotating the pavement about the inner edge of the pavement.

Advantages of Rotation of Pavement

The advantages of attainment of superelevation by rotation of pavement about the inner edge of the pavement are as follows:

1. Avoids the Drainage Problem in Flat Terrain

In flat terrain, the conventional method of achieving superelevation by raising the outer edge of the pavement results in a drainage problem. The raised outer edge of the pavement obstructs the flow of water, leading to the accumulation of water on the pavement, causing skidding and hydroplaning. Rotation of pavement avoids this problem by achieving superelevation without raising the outer edge of the pavement.

2. Does Not Change the Vertical Alignment of Road

The rotation of pavement does not change the vertical alignment of the road. The pavement is rotated about the inner edge of the pavement, and the outer edge remains at the same level. Therefore, the rotation of pavement does not affect the longitudinal gradient of the road.

3. Balances the Earthwork

Rotation of pavement results in balancing the earthwork. The earthwork refers to the excavation and embankment required for the construction of the road. The rotation of pavement creates a natural slope towards the inner edge of the pavement, reducing the amount of excavation and embankment required.

4. Preferable in Steep Terrain

Rotation of pavement is preferable in steep terrain. In steep terrain, the conventional method of achieving superelevation by raising the outer edge of the pavement results in a high embankment on the outer edge, which is unstable and prone to landslides. Rotation of pavement avoids this problem by achieving superelevation without raising the outer edge of the pavement.

Conclusion

Attainment of superelevation by rotation of pavement about the inner edge of the pavement is preferable in flat terrain, avoids the drainage problem, does not change the vertical alignment of the road, balances the earthwork, and is preferable in steep terrain.