ASTM C1314

[manhattancc]

How do you calculate the compressive strength of a
fully grouted prism. The code states use the net mortar bedded area. Is it the net area or the gross area of the prism?

 

[concretemasonry]

Are your designing, testing or verifying?

Solid grouted prisms are rare and pose many problems and variables.

Since it is obviously cheaper to use higher strength units the variables are usually avoided.

If you have a prism that has grout that is too strong, the gross average compressive strength is higher than the masonry wall fibers that are usually the most highly stressed. This is because grout is really used to transfer the loads from the rebar in the grouted cells to the masonry units which have a specified f'm. Strong grout is routinely avoided and frequently may have a maximum allowable in relationship to the f'm of a hollow prism.

There many high rise masonry structures (10 to 20 stories) essentially built to ACI 539 codes/specifications that are partially reinforced and never required a the cost penalties and problems of a solid prism.

Dick