SEDL / STP / STP1512-EB / STP49106S

Proposed Masonry Specified Compressive Strength Requirements

Bennett, Richard M.
The Univ. of Tennessee—Knoxville, Knoxville, TN

Pages: 10    Published: Jan 2010

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Abstract

Currently the TMS 602-08, “Specification for Masonry Structures,” allows the specified compressive strength of masonry, f^m′, to be determined using either the unit strength method or the prism test method. With regard to prism testing, the specification gives no requirements in terms of the number of prisms to be tested or how to use the results of the prism testing to determine the specified compressive strength. This paper summarizes the requirements of other codes and specifications and examines a statistical basis for determining a prism compressive strength, including the effects of sample size. It is recommended to use the 75th percent confidence on the ten-percentile value. This is reasonably consistent with other codes and specifications. A minimum of ten tests is recommended.