Because of the imprecise nature of masonry construction and the interaction of components, assembly properties (e.g. bending stress, axial stress, modulus of elasticity) are given as fractions of the masonry assembly compressive strength, f `m. As a structural designer, we need to understand how to use f `m and its relationship to design and construction. In this topic, we will learn about how f `m is established, verified, or specified; the consequences of special field inspection, and the relationship of half and full stress design to f `m
On-Line Lecture:
Problem Assignment:
- Is it necessary to make and test prisms for CMU assemblies when f `m = 1500 psi and 1/2 stresses are used? Support your answer.
- What are the strength values for the concrete block units and grout, if a f ` m of at least 3000 psi is desired? What type of mortar should be used?
- Why is the ultimate strength of an assembly less than the ultimate strength of the individual components?
- Estimate how many QC prisms must be taken and tested for a 60' x 200' x 12' building if using method 1 to verify f `m.
