Masonry Magazine September 1980 Page. 22
REQUEST FOR PROPOSALS
continued from page 11
Procedure for analysis and design and permissible values to be used for brick masonry, both reinforced and un-reinforced. Shortly thereafter, the National Concrete Masonry Association published a design standard for hollow and solid concrete unit masonry, both reinforced and un-reinforced.
These two standards are currently in their second generation, dated BIA 1969 and NCMA 1971, respectively. The standards are entirely parochial. The BIA standard covers brick; the NCMA standard covers block.
Much of the masonry construction in the U.S. is neither all-brick nor all-block, but rather a combination and composite of both products. Unfortunately, there is no proven and accepted standard that covers the design of composites, brick and block, masonry.
The Advisory Council recommended development of a research project to:
1. Produce a composite wall study including design methods and consideration of dissimilar units.
2. Determine effects of creep and shrinkage in masonry design.
This study is envisioned to cover the inherent differences in the two materials as well as their similarities. Items to be considered may be:
a) Compressive Strength, f
b) Modulus of Elasticity, E
c) Modulus of Rigidity, E,
d) Plastic Flow (Creep)
e) Coefficient of Thermal Expansion
f) Coefficient of Moisture Expansion
g) Shrinkage on Drying
h) Tensile Strength, I'
i) Shear Strength, v
j) Effects of Mortar Types
k) Prism Height Uniformity
l) Shear Strength of Collar Joints including the Effects of Masonry Headers & Joint Reinforcement
Ideally, the study would define each of the items listed with values for use in general design and the procedure for obtaining the proper values for special circumstances.
3.0 CONTENTS OF PROPOSAL
1. Identification of the problem.
2. Specific research objectives.
3. Research plan to meet the objectives.
4. Anticipated results: Their utilization and benefits.
5. Qualification of the principal investigator and other key personnel.
6. Reporting procedure.
7. Estimated total cost and period of performance.
4.0 REFERENCES
1. BIA Standard
2. NCMA Standard
3. Recommended Practice
REQUEST FOR PROPOSAL No. 4
1.0 MASONRY:
Bond between units and mortar, water penetration, and strength and compatibility
2.0 STATEMENT OF NEED
A need exists to characterize the materials of masonry construction, at least the compatibility of the materials, in composites. Construction materials historically have been for the most part evaluated singly. The need exists to couple the individual materials and require satisfactory conformance to a performance specification, or disallow their combination.
Masonry construction has passed the test of time. Longevity in masonry is well documented. Under the present economic conditions, however, taller and thinner walls are causing some incompatibility, as evidenced mostly by leaking walls. Combinations once entirely satisfactory for low-rise structures are now classified as borderline, or failing, in their performance characteristics. Loadbearing masonry is not receiving keen attention; consequently the compatibility of materials in the tensile bond (flexural, flexural bond and shear bond) areas are also more important. Heretofore, these specific properties were recognized, but their significance in terms of the success or failure of the masonry was considered to be less important.
The time is appropriate to develop performance specifications for the materials of construction, both singly and when coupled as masonry assemblages, or full-scale walls.
Summary of the Program
The following is a tabular summary of the full program:
Mortars. There are twenty (20) different mortar mixes and types included in the program.
Brick Units. There are six (6) different brick units included in the program. In addition, the two (2) high-suction units are to be wetted and included for a total of eight (8) different brick.
Concrete Masonry Units. There are six (6) different concrete masonry units included in the program.
Material Tests. The are twenty-four (24) different tests to be performed on the materials used in this program. They are to be as follows:
Brick. Six (6) tests on brick units. ASTM C67 for:
Modulus of Rupture
Compressive Strength
Absorption (2)
Initial Rate of Absorption
Block. Four (4) tests on block units. ASTM C140 for:
Compressive Strength
Absorption
Drying Skrinkage
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