# Masonry Walls

Water pressure on masonry walls

### Key Facts

**Gyroscopic Couple**: The rate of change of angular momentum () = (In the limit).

- = Moment of Inertia.
- = Angular velocity
- = Angular velocity of precession.

**Blaise Pascal**(1623-1662) was a French mathematician, physicist, inventor, writer and Catholic philosopher.

**Leonhard Euler**(1707-1783) was a pioneering Swiss mathematician and physicist.

## Overview

Consider a vertical masonry wall having water on one of its sides as shown in figure. Now consider a unit length of the wall. We know that the water pressure will act perpendicular to the wall. A little consideration will show, that the intensity of pressure, at the water level, will be zero, and will increase by a straight line law to at the bottom as shown in figure. Thus the pressure diagram will be a triangle. The total pressure on the wall will be the area of the triangle, i.e., This pressure will act through the center of gravity of the pressure diagram. Let, = Depth of the center of pressure from the water surface. We know that the c.g. of triangle is at a height of from the base, where is the height of the triangle. Therefore depth of center of pressure from the water surface, Thus the pressure of water on a vertical wall will act through a point at a distance from the bottom, where is the depth of water.Example:

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##### Example - Water pressure on masonry walls

Problem

One of the walls of a swimming pool contains 4m deep water. Determine the total pressure on the wall, if it is 10m wide.

Workings

Given,

- Depth of water, H = 4m
- Width of wall = 10m

Solution

Total pressure on the wall = 784.8 KN