Masonry Magazine December 1993 Page. 32
CONSTRUCTION TOLERANCES
2.3.2.1 Foundations
2.3.2.1.1 Prior to the start of masonry construction, the contractor shall verify:
(a) That foundations are constructed with tolerances conforming to the requirements of ACI 117.
(b) That reinforcing dowels are positioned in accordance with the Project Drawings.
ACI 117
Section 3 Foundations
3.2 Lateral alignment
3.2.1 Footings
As cast to the center of gravity as specified; 0.02 times width of footing in direction of misplacement but not more than 2 in.
Supporting masonry. 1/2 in.
3.3-Level alignment
3.3.1 Footings
Top of footings supporting masonry 1/2 in.
Top of other footings +1/2 in., -2 in.
3.4-Cross-sectional dimensions
3.4.1 Footings
3.4.1.1 Horizontal dimension of formed members +2 in., -1/2 in.
3.4.1.2 Horizontal dimension of unformed members cast against soil, 2 ft or less +3 in., -1/2 in.
greater than 2 ft but less than 6 ft +6 in., -1/2 in.
over 6 ft +12 in., -1/2 in.
3.4.1.3 Vertical dimension (thickness) 5 percent
2.3.3.2 Tolerances Erect masonry within the following tolerances from the specified dimensions:
(a) Dimension of elements
1. In cross-section or elevation -1/4 in., +1/2 in.
2. Mortar joint thickness
bed + 1/8 in.
head -1/4 in., +3/8 in.
collar -1/4 in., +3/8 in.
3. Grout space or cavity width -1/4 in., +3/8 in.
(b) Elements
1. Variation from level:
bed joints +1/4 in. in 10 ft
top surface of bearing +1/2 in. maximum
2. Variation from plumb walls1/4 in. in 10 ft
+1/2 in. maximum
3. True to a line +1/4 in. in 10 ft
+3/8 in. in 20 ft
±1/2 in. maximum
4. Alignment of columns and walls (bottom versus top) +1/4 in. in 10 ft
+3/8 in. in 20 ft
+1/2 in. maximum
+1/2 in. for bearing walls
+3/4 in. for nonbearing walls
(c) Location of elements
1. Indicated in plan +1/2 in. in 20 ft
+3/4 in. maximum
2. Indicated in elevation +1/4 in. in story height
+3/4 in. maximum
(d) In placing of reinforcement. See Article 3.3.3.2
3.3.3.2 Tolerances for placing reinforcement
(a) Tolerances for the placement of steel in walls and flexural elements shall be ±1/2 in. when the distance from the centerline of steel to the opposite face of masonry, d, is equal to 8 in. or less, ±1 in. for d equal to 24 in. or less but greater than 8 in., and ±1-1/4 in. for d greater than 24 in.
(b) In walls, for vertical bars, 2 in. from the location along the length of the wall indicated on the Project Drawings.
CONSTRUCTION PROCEDURES
2.3.2 Preparation
2.3.2.2 Cold weather construction - Implement cold weather construction procedures when any of the following conditions exist:
(a) The ambient temperature falls below 40°F,
(b) The temperature of masonry units is below 40°F.
In addition:
1. Do not lay masonry units having a temperature below 20°F. Remove visible ice on masonry units before the unit is laid in the masonry.
2. Heat mortar sand or mixing water to produce mortar temperatures between 40°F and 120°F at the time of mixing. Maintain mortar above freezing until used in masonry.
3. When ambient temperature is between 25°F and 20°F use heat sources on both sides of the masonry under construction and install wind breaks when wind velocity is in excess of 15 mph.
4. When ambient temperature is below 20°F, provide an enclosure for the masonry under construction and use heat sources to maintain temperatures above 32°F within the enclosure.
5. When mean daily temperature is between 40°F and 32°F, protect completed masonry from rain or snow by covering with a weather resistive membrane for 24 hr after construction.
6. When mean daily temperature is between 32°F and 25°F, completely cover completed masonry with a weather resistive membrane for 24 hr after construction.
7. When mean daily temperature is between 25°F and 20°F, completely cover completed masonry with insulating blankets or equal protection for 24 hr after construction.
8. When mean daily temperature is below 20°F, maintain masonry temperature above 32°F for 24 hr after construction by enclosure with supplementary heat, by electric heating blankets, by infrared heat lamps or by other acceptable methods.
2.3.2.3 Hot weather construction Implement when the ambient air temperature exceeds 100°F, or 90°F with a wind velocity greater than 8 mph. Do not spread mortar beds more than 4 ft ahead of masonry. Set masonry units within one minute of spreading mortar.