ABSTRACT
Walls made of such materials as brick or stone may be supposed, for the purposes of calculation, to be composed of uncemented blocks, or cemented blocks. Assuming that the strength of the materials and the accuracy of the bonding is uniform throughout a wall, its power to resist external forces, neglecting strength of mortar, will depend upon the leverage of external forces as compared with the leverage of the mass or weight of the wall acting at its centre of gravity. Wind pressure is the principal disturbing force acting on walls, and those joints which have to withstand the greatest stress are at the lowest position, where the wind exerts the greatest turning moment. If the wall be of uniform section throughout, it is quite sufficient if the strength of the lowest joint be calculated; but if the thickness be variable, the lowest joint at each change of section must be taken.
