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[BS] A106.2.3.1 Concrete Masonry Units and Structural Clay Load-Bearing Tile
Grouted or ungrouted hollow concrete masonry units shall be tested in accordance with ASTM C140. Grouted or ungrouted structural clay load-bearing tile shall be tested in accordance with ASTM C67.
[BS] A106.2.3.2 In-Place Mortar Joint Shear Tests
Mortar joint shear test values, vto, shall be obtained by one of the following: 
  1. ASTM C1531.
  2. For masonry walls that have high shear strength mortar, or where in-place testing is not practical because of crushing or other failure mode of the masonry, alternative procedures for testing shall be used in accordance with Section A106.2.3.2.
[BS] A106.2.3.3 Alternative Procedures for Testing Masonry
The splitting tensile strength of existing masonry, fsp, or the prism strength of existing masonry, f'm, is permitted to be determined in accordance with ASTM C496 and calculated by the following equation:
(Equation A1-1)
[BS] A106.2.3.4 Location of Tests
The shear tests shall be taken at locations representative of the mortar conditions throughout the building. Test locations shall be determined at the building site by the registered design professional in charge. Results of all tests and their locations shall be recorded.
[BS] A106.2.3.5 Number of Tests
The minimum number of tests per masonry class shall be determined as follows:
  1. At each of both the first and top stories, not less than two tests per wall or line of wall elements providing a common line of resistance to seismic forces.
  2. At each of all other stories, not less than one test per wall or line of wall elements providing a common line of resistance to seismic forces.
  3. In any case, not less than one test per 1,500 square feet (139.4 m2) of wall surface and not less than a total of eight tests.
[BS] A106.2.3.6 Minimum Quality of Mortar
  1. Mortar shear test values, vto, in pounds per square inch (kPa), shall be obtained for each in-place shear test in accordance with the following equation:
    (Equation A1-2)
    where:
    Vtest   = Load at first observed movement.
    Ab  = Total area of the bed joints above and below the test specimen.
    PD+L  = Stress resulting from actual dead plus live loads in place at the time of testing.
  2. Individual unreinforced masonry walls with more than 50 percent of mortar test values, vto, less than 30 pounds per square inch (207 kPa) shall be pointed prior to and retested.
  3. The lower bound mortar shear strength, vtL, is defined as the mean minus one standard deviation of the mortar shear test values, vto.
  4. Unreinforced masonry with mortar shear strength, vtL, less than 30 pounds per square inch (207 kPa) shall be pointed and retested or shall have its structural function replaced, and shall be anchored to supporting elements in accordance with Sections A106.2.1 and A113.8. When existing mortar in any wythe is pointed to increase its shear strength and is retested, the condition of the mortar in the adjacent bed joints of the inner wythe or wythes and the opposite outer wythe shall be examined for extent of deterioration. The shear strength of any wall class shall be not greater than that of the weakest wythe of that class.
[BS] A106.2.3.7 Minimum Quality of Masonry
Where the alternative procedures of Section A106.2.3.2 are used to determine masonry quality, the following minimums apply:
  1. The minimum average value of splitting tensile strength, fsp, as calculated by Equation A1-1 shall be 50 pounds per square inch (344.7 kPa).
  2. Individual unreinforced masonry walls with average splitting tensile strength of less than 50 pounds per square inch (344.7 kPa) shall be pointed and retested.
  3. The lower-bound mortar strength fspL is defined as the mean minus one standard deviation PD+L of the splitting tensile test values fsp.
[BS] A106.2.3.8 Collar Joints
The collar joints shall be inspected at the test locations during each in-place shear test, and estimates of the percentage of surfaces of the adjacent wythe that are covered with mortar shall be reported along with the results of the in-place shear tests.
[BS] A106.2.3.9 Unreinforced Masonry Classes
Existing unreinforced masonry shall be categorized into one or more classes based on shear strength, quality of construction, state of repair, deterioration and weathering. A class shall be characterized by the masonry shear strength determined in accordance with Section A108.2. Classes are defined for whole walls, not for small areas of masonry within a wall. Discretion in the definition of classes of masonry is permitted to avoid unnecessary testing.
[BS] A106.2.3.10 Pointing
Deteriorated mortar joints in unreinforced masonry walls shall be pointed in accordance with the following requirements:
  1. Joint preparation. Deteriorated mortar shall be cut out by means of a toothing chisel or nonimpact power tool until sound mortar is reached, to a depth not less than 3/4 inch (19.1 mm) or twice the thickness of the joint, whichever is less, but not greater than 2 inches (50 mm). Care shall be taken not to damage the masonry edges. After cutting is complete, all loose material shall be removed with a brush, or air or water stream.
  2. Mortar preparation. The mortar mix shall be proportioned as required by the construction specifications and manufacturer's approved instructions.
  3. Packing. The joint into which the mortar is to be packed shall be dampened but without free-standing water. The mortar shall be tightly packed into the joint in layers not exceeding 1/4 inch (6.4 mm) deep until it is filled; then it shall be tooled to a smooth surface to match the original profile.
Nothing shall prevent pointing of any masonry wall joints before testing is performed in accordance with Section A106.2.3, except as required in Section A107.2.

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