Pile Capacity

Vertical downwards loads (Compression): Pile carrying capacity for vertical downward loads, comes from two things: The frictional resistance over their side face area and Their bottom tip resistance (end bearing resistance) foundations 2 So, piles generate friction force on their side face, plus develop strength at the tip. Tip resistance is also called “end bearing” […]

Deep Foundations (Pile Foundations)

Deep foundations, also called as pile foundations, are used when there is not sufficiently strong soil at a reasonable depth, and using shallow foundations would cause failure or excessive settlement of the structure, even if that same soil can be a sufficiently strong foundation material for a lighter project. For example, for a bridge, where […]

Shallow foundations

Design: Shallow foundations are used where the soil has enough bearing capacity and shear strength (in other words strong enough) at a reasonably close depth. The Federal Highway Administration defines shallow foundations as, “a foundation that bears at a depth less than about two times the foundation width”. Under soil mechanics, we have said that […]


In the previous posts we introduced earth materials from a civil engineering point of view and gave an overview of soil mechanics. The entire soil mechanics concepts are studied not for the sake of understanding soils only, but to use them in designing better foundations, slopes and retaining structures. That is when we put the […]

Stress Increase in Soils

Stress Increase in Soils

We have looked at bearing capacity of the soil in the previous section but checking only that is not enough. We must also make sure that, even if the soil can bear the pressure, it will not settle too much.  Before calculating settlement amount in soil however, we must first know the stresses in soil. […]

Bearing Strength of Soil

Bearing Strength of Soil

So far, under soil strength section, we have explained total and effective stresses, pore pressure, angle of internal friction, shear strength, lateral earth pressure coefficient, and cohesion of clay. Now we are ready to start seeing how these are actually used, when designing foundations.   In this subsection we will now learn about bearing strength, […]