Principles of Calculated Brickwork

Calculated Brickwork ~ for small and residential buildings up to three storeys high the sizing of load bearing brick walls can be taken from data given in Part C of Approved Document A. The alternative methods for these and other load bearing brick walls are given in BS 5628 Code of practice for use of masonry.

The main factors governing the load bearing capacity of brick walls and columns are:-

1. Thickness of wall.

2. Strength of bricks used.

3. Type of mortar used.

4. Slenderness ratio of wall or column.

5. Eccentricity of applied load.

Thickness of wall ~ this must always be sufficient throughout its entire body to carry the design loads and induced stresses. Other design requirements such as thermal and sound insulation properties must also be taken into account when determining the actual wall thickness to be used.

Effective Thickness ~ this is the assumed thickness of the wall or column used for the purpose of calculating its slenderness ratio see page 328.

Typical Examples ~

Strength of Bricks ~ due to the wide variation of the raw materials and methods of manufacture bricks can vary greatly in their compressive strength. The compressive strength of a particular type of brick or batch of bricks is taken as the arithmetic mean of a sample of ten bricks tested in accordance with the appropriate British Standard. A typical range for clay bricks would be from 20 to 170 MN/m ²