Title:
Sampling For Attributes
Author(s):
Donald E. Dixon
Publication:
Concrete International
Volume:
8
Issue:
3
Appears on pages(s):
53-55
Keywords:
DOI:
Date:
3/1/1986
Abstract:
It is often necessary to determine the properties of reinforced concrete in existing structures. Routine sampling and testing satisfies the requirements. Sometimes it is necessary to dermine both an overall property and its variatios, such as compressive strength and standard deviation of compressive strength. Throuhg the use of a case hishtory, the sampling requirements and procedures for the testing program and the proceduresused to determine the appropriate samplet size are discussed. The procedures include cover for reinforcing steel and slab thickness for several multistory parking garages. The statistical analysis procedures used are also presented. The empasis is on sampling procedures necessary for an unbiased representation of the in-place condition. The determination of the sample size necessary to obtain an anticipated confidence in the results is presented. The procedure recognizes estimates of the variations to be expected but uses the actual results (and variations thereof) to determine the actual confidence obtained.