Title:
Equivalent Specified Concrete Strength from Core Test Data
Author(s):
F. Michael Bartlett and James G. MacGregor
Publication:
Concrete International
Volume:
17
Issue:
3
Appears on pages(s):
52-58
Keywords:
compressive strength; concrete; concrete cores; evaluation; statistical analysis; Structural Research
DOI:
Date:
3/1/1995
Abstract:
A simple procedure is presented for the determination of an equivalent specified concrete strength from a small number of core test results for the assessment of the safety of an existing structure. The procedure yields a concrete strength value which is consistent with the statistical description of the specified concrete strength at the time of initial design and so can be substituted directly for f' c in conventional resistance equations with the customary resistance factors. Practical guidelines are presented concerning the scope of the core drilling program, the sample size, and the detection of spurious high or low test results which should be purged from the data set. Use of the proposed procedure is illustrated by an example calculation.