In case of well foundation, grip length is defined as the

Explanation:

• Grip length refers to the embedment depth of the well below the maximum scour level.

• It is the depth provided to ensure stability of the well foundation against:

  • Overturning

  • Sliding

  • Uplift

  • Lateral loads (especially in bridge foundations)

• Scour is the removal of soil around a foundation due to flowing water.

• The maximum scour level represents the lowest level the riverbed may reach due to extreme flow conditions.

• The well must penetrate below this level to remain stable even during floods.

 Additional Information

Well Foundation: A deep foundation type used mostly for heavy loads, especially for bridges, piers, and waterfront structures. It consists of a large-diameter hollow cylindrical well sunk into the ground to a suitable depth.

• The cutting edge is the sharp bottom edge of the well, designed to cut through soil or rock during sinking.

​Grip length is important because:

• It provides skin friction between the well’s cylindrical surface and the surrounding soil, enhancing stability.

• It resists uplift and lateral loads acting on the foundation.

• Ensures that the well foundation remains stable under various load conditions, including scour and soil movement.

Sinking process: The well is gradually sunk by excavating soil inside the well or by adding weights, and the cutting edge helps penetrate the soil or rock below.

Design considerations include:

• Grip length should be sufficient to provide adequate friction and prevent sliding.

• The length also affects the settlement and bearing capacity of the foundation.

• Must consider scour depth if located in water bodies; foundation depth should be below maximum scour level to prevent exposure.