Masonry technology 3. Masonry cutting rules

Masonry, made of individual bricks, connected with the mortar into a single whole, should be a monolith, in which the laid stones would not move under the influence of loads acting on the masonry. The forces acting on the masonry are confronted mainly by a stone (the solution is much less durable). Therefore, it is necessary that the stone perceived only compressive forces, and mostly - the bed. To prevent the stones from moving, they are laid in compliance with certain conditions, called the rules for cutting masonry (Fig. 11.3).

Rule one. Masonry perform flat rows perpendicular to the current force, i.e. the rule sets the maximum allowable angle of inclination of the force acting on the horizontal row of masonry. The vertical tolerance of the force is no more than 15 ... 17 °, it depends on the friction force of the stone on the surface of the mortar. Rule two. Longitudinal and transverse vertical joints in the masonry should not be through the height of the structure, the masonry will be dissected into separate columns. The rule regulates the location of the vertical planes of cutting masonry relative to the bed. In relation to the front surface of the wall, the seams should be perpendicular or parallel to it. Failure to comply with this rule may cause wedging of the masonry rows.

Rule three. The planes for vertical cutting of masonry of adjacent rows should be shifted, that is, stones should be located under each vertical seam of a given row of masonry, but not seams. The rule determines the relative position of the vertical longitudinal and transverse joints in adjacent rows of masonry. The stones of the overlying row must be laid on the underlying row so that they overlap the vertical seams between the stones in the longitudinal and transverse directions, laying should be carried out with the ligation of the seams

Fig. 11.3. The rules for cutting masonry:

a - effect on laying of oblique force; b - correct, mutually perpendicular arrangement of the vertical planes of masonry cutting; in - the same, wrong; d - laying with proper ligation of vertical seams

in adjacent rows. Such a ligation of the seams eliminates the danger of the masonry stratification into separate columns, which, working independently, are not able to perceive the efforts that monolithic masonry can withstand.

When used in masonry durable cement-sand mortars, there may be some deviations from these rules. It is allowed not to tie up vertical longitudinal seams in five adjacent rows or vertical transverse seams in three adjacent rows of masonry.