Well Foundation and Pile Foundation

Well Foundation and Pile Foundation

Well foundation and pile foundation both have unique advantages and their limitations. Choosing any type of foundation is depend on three main criteria- Soil Properties, Design load and Capital expenditure.

Pile foundation is generally used when Soil load bearing capacity is very less and finding hard strata below ground is difficult. If bridge is located in such places where these condition met, we choose friction Pile foundation.

But when we need to construct bridge where sandy soil present and hard strata is easily available, we choose well foundation. We use cassion in those cases too where top surface is weak and down graded soil like expansive soils, peat, musk etc but below its desirable bering capacity soil like sandy soil present. There are many advantages associated with well or pier foundation as-

1. Cassion can float in water bodies so it is easy to install at correct location cheaply.
2. In cassion, whole volume is filled with concrete so vertical settlement is negligible over time.
3. Cost of installing cassion and drilling hole for same is cheaper than Pile foundation in the same location. Further, it also eliminates the cost of constructing Pile caps.
4. It can withstand large lateral loads and moment that can occur in case of bridges, chimneys, tall tower etc.
5. Due to its size and heavy dead load, it can easily withstand large vibration and shocks.