280. As a usual thing, the brickwork in walls is of ample strength to carry the loads imposed. The principal loads come on the piers, arches, and under bearing plates. Of course, the strength varies, owing to different conditions that may exist: the strength of the bricks taken separately, the materials and quality of the mortar used in laying the brickwork, the workmanship and bond, as well as the age of the brickwork. The following table gives the safe strength of brickwork based on the quality of the brick in various sections of the country:

Table 4. Strength Of Brick Masonry

Materials.

Strength.

Pounds per Sq. In.

Tons per Sq. Ft.

Eastern Brick.

Hard burned brick, laid in good lime mortar..........

100-140

7-10

Same, laid in 1 to 2 Rosendale cement mortar............

150-165

10 3/4-11 3/4

Same, laid in 1 to 3 Rosendale cement and lime mortar.. ..

195

14

Same, laid in 1 to 2 Portland cement mortar............

210

15

Western Brick.

Hard burned brick, laid in 1 to 2 Louisville mortar......

145

10 1/2

Same, laid in 1 to 2 Portland cement mortar............

175

12 1/2

The strength and efficiency of all brick-bearing piers depend largely upon the thoroughness with which they are bonded, and the architect or superintendent should carefully watch the building of them.