Number of Tests Versus Design Pile Capacity

Abstract

According to current practice, the average tested capacity of single piles is multiplied by a predefined traction in order to obtain the design capacity of a single pile. This fraction remains constant regardless of the number of piles tested. In this paper a simple procedure is developed whereby advantage can be taken of the increased reliability of the data that follows from the increased number of piles tested. It is shown that for the same reliability, increasing the number of tests can substantially increase the fraction by which the average of test results is multiplied in order to obtain the design value. The increase is significant even if the number of tests increases only from one to two. A simple procedure is also developed for taking into account the number of samples tested in determining representative strength of a material in an installation.