Retaining walls and other gravity-dependent structures
Consider the pressure distribution on the vertical surface AB in Fig. 11.7. The pressure at a depth His 'YwB giving the base of the diagram.
The magnitude of the resultant thrust is given by the area of the diagram:
This resultant will act through the centre of area of the pressure triangle, i.e. at a height of H/3 above B. It is important to note that the depth is always measured from the surface of the liquid - see the following example.