When designing a loadbearing masonry structure, certain rules of thumb can help building designers, owners and contractors estimate typical loads and sizes that walls and columns experience. Keeping in mind the cumulative effects of workmanship, rain, freeze-thaw and fatigue, building teams may use the following rules of thumb for project planning and estimating in the schematic phase.
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Ā Loadbearing walls. First, determine the total width of floor and roof decks that contribute load to a 12-in. length of wall. Assuming that the wall is reinforced, brick masonry assemblies of the following widths can support the following total widths of deck:
-An 8-in. wall: 250 feet.
-A 12-in. wall: 500 feet.
-A 16-in. wall: 750 feet.
-A 20-in. wall: 1,000 feet.
For a reinforced concrete wall, the rule is:
-An 8-in. wall: 250 feet.
-A 12-in. wall: 450 feet.
-A 16-in. wall: 600 feet.
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Ā Loadbearing columns. For reinforced concrete or brick columns, first determine the total roof and floor area supported by the post. Then, assume the following column dimensions for the following areas. For reinforced concrete:
-A 12-in. column: 1,200 square feet.
-A 16-in. column: 2,000 square feet.
-A 20-in. column: 3,500 square feet.
-A 24-in. column: 5,500 square feet.
For reinforced brick masonry:
-A 12-in. column: 2,000 square feet.
-A 16-in. column: 3,000 square feet.
-A 20-in. column: 4,000 square feet.
-A 24-in. column: 6,000 square feet.
