Masonry Magazine October 1975 Page. 15
FIG. 10
Transverse Test
Horizontal Uniform Loading (Air Bag)
The test procedure is as follows: The specimen once placed in the test frame, which usually has a span of 6 in. (1.524 cm) less than the specimen size, is instrumented only to measure the center of span deflection. The concentrated load method, whether the specimen is vertical or horizontal, applies two equal loads at a distance of one quarter of the span length from each support.
The uniform loading is applied in either position, using an air bag. See Figs. 10 and 11. The loads should be applied in increments with deflection readings taken and recorded at each increment. Instrumentation should be removed at approximately 75 to 80 percent of anticipated ultimate load to prevent damage to the instrument at failure.
The report of the test should provide a stress-deflection curve and ultimate transverse strength. The transverse stress at ultimate may be calculated as follows:
f₁ = M
S
where:
f', ultimate transverse stress, psi (kgf/cm²)
M bending moment for 1-ft (3.048 cm) wide strip, in.-lb. (kgf-m)
S section modulus of the specimen for 1-ft (3.048 cm) wide strip, in.³ (cm³)
The moment for uniformly loaded specimens is calculated as follows:
M-
w/2 x 12
8
where:
wuniform load, psf (kgf/cm²)
= span length, ft (cm)
The moment for the concentrated loading may be calculated as follows:
M =
P/ x 12
4
where:
P concentrated loads at the quarter points for 1-ft (3.048 cm) wide strip, lb (kgf)
The section modulus for the specimen must take into account whether the masonry units are solid (up to 25 percent cored) or hollow (26 to 40 percent cored). Calculations for the section modulus of solid units would be as follows:
S =
bd²
6
where:
bwidth of 1-ft (3.048 cm) wide strip, in. (cm)
d thickness of specimen, in. (cm)
FIG. 11
Transverse Test
Vertical Uniform Loading (Air Bag)
great effect on the results obtained. If the span is normal to the bed joints, simulating a wall supported by floor and roof framing in normal construction, the ultimate strengths obtained will be considerably less than those with spans parallel to the bed joints. The panel oriented with a span parallel to bed joints simulates a wall which in normal masonry construction is laterally supported by columns or pilasters.
The specimens for this method of test should be at least 4 ft by 8 ft (1.219 mx 2.438 m) and the same thickness as the proposed project walls. Three specimens are required for this method of test. The specimens should be built using the type of brick, mortar and bonding pattern proposed for the construction project. The specimens should be built using inspected workmanship as described earlier.