Masonry Magazine December 1993 Page. 33
1.2- Definitions
Area, gross cross-sectional The areas delineated by the out-to-out dimensions of masonry in the plane under consideration.
Area, net cross-sectional-The area of masonry units, grout, and mortar, crossed by the plane under consideration based on out-to-out dimensions.
Collar joint-Vertical, longitudinal joint between wythes of masonry or between masonry and back up construction which is permitted to be filled with mortar or grout.
Compressive strength of masonry-Maximum compressive force resisted per unit of net cross-sectional area of masonry, determined by the testing of masonry prisms; or a function of individual masonry units, mortar, and grout in accordance with the provisions of these specifications.
Partition wall- An interior wall without structural function.
Running bond - The placement of masonry units such that head joints in successive courses are horizontally offset at least one-quarter the unit length.
Specified compressive strength of masonry, f' - Minimum compressive strength, expressed as force per unit of net cross-sectional area, required of the masonry used in construction by the project documents and upon which the project design is based. Whenever the quantity f' is under the radical sign. the square root of the numerical value only is intended, and the result has units of pounds per square inch (psi).
Stack bond For the purpose of this specification, stack bond is other than running bond. Usually the placement of masonry units is such that head joints in successive courses are vertically aligned.
Wall A vertical element with a horizontal length to thickness ratio greater than 3, used to enclose space.
Wall, load-bearing - A wall carrying vertical loads greater than 200 lb/ft in addition to its own weight.
Work - The furnishing and performance of all equipment, services, labor, and materials required by the contract documents for the construction of masonry for the project or part of project under consideration.
Wythe Each continuous vertical section of wall, one masonry unit in thickness.
1.5- Quality assurance
1.5.1 Inspection and testing
1.5.1.1 Tests required to document submittals, certify product compliance with these Specifications prior to use in construction, establish mix designs, provide acceptability of changes requested by the Contractor, or appeal rejection of material found defective by Owner's test, shall be performed by accepted laboratories under Contractor's responsibility. Cost of these services shall be paid by the Contractor.
1.5.1.2 When required, the Owner will employ a qualified professional engineer or surveyor to survey foundations, and report any deviation from the tolerances specified in Article 2.3.2.1 to the Architect/Engineer, prior to the start of masonry.
1.6-Compressive strength determination
1.6.2 Unit strength method
Table 1.6.2.2- Compressive strength of masonry based on the compressive strength of concrete masonry units and type of mortar used in construction
| Net area compressive strength of concrete masonry units, psi | Net area compressive strength of masonry, psi* |
| --- | --- |
| Type M or S mortar | Type N mortar | |
| 1250 | 1300 | 1000 |
| 1900 | 2150 | 1500 |
| 2800 | 3050 | 2000 |
| 3750 | 4050 | 2500 |
| 4800 | 5250 | 3000 |
* For units of less than 4 in. height, 85 percent of the values listed.
1.6.3 Prism test method
Hollow unit ungrouted prism
Hollow unit grouted prism
Solid unit prism
* Contruct prisms in stack bond, one unit long and thick with a full mortar bed.
* Construct concrete masonry prisms with height to thickness ratios in the range from 1.33 to 5.0.
* Provide a minimum of one joint in hollow unit masonry prisms.
Table 1.6.3.3(c)- Correction factors for concrete masonry prism strength
| Prism height to thickness ratio | 1.33 | 2.0 | 3.0 | 4.0 | 5.0 |
| --- | --- | --- | --- | --- | --- |
| Correction factor | 0.75 | 1.00 | 1.07 | 1.15 | 1.22 |