What are the Forces Acting on Foundations
Foundations are normally subjected to vertical loads which are resisted by compressive stress generated in the soil. However, the action of wind on tall structures like chimneys and towers induce horizontal forces. The horizontal forces are also caused on bridge foundations by traction forces..
If horizontal forces are large, they can be resisted using deep foundations such as wells, caissons or piles. Shallow foundations are not capable of resisting them. Large moments acting on foundations again require tension or anchor piles. Machine foundations are subjected to cyclic loadings and special arrangements are needed to keep the vibrations within specified limits.