Title: Miner’s Rule with Respect to Plain Concrete Variable Amplitude Tests
Author(s): A. J. M. Siemes
Publication: Symposium Paper
Appears on pages(s): 343-372
Keywords: amplitude; compression; failure; fatigue (materials);
fatigue tests; plain concrete; stresses; tests.
As usual with other materials the constant-amplitude test (Wdhler) is widely adopted as the criterion for the fatigue sensitivity of concrete. In this test the number of load repetitions Ni the material can stand before failure occurs, is determined. In general stresses vary in a more erratical and random way. As for concrete from tests no relation is known between this kind of loading and the service life of a structure, Miner's rule is adopted for predicting this life on basis of constant-amplitude tests. According to this rule failure will occur if the following condition is satisfied: where c is the number of stress cycles during the service life. As the number of stress repetitions N. is a stochastic quantity, Miner's rule will also be stochastic. An experimental verification of the rule is therefore complicated. So a theory is giventose-parate in Miner's rule the possible uncertainty in the rule from the influence of the dispersion in N. With the aid of this theory test results of about 220 variable-amplitude tests have been verified. Miner's rule proved to be very accurate to predict the life-time of the test cylinders. At the moment the test program is continued with random loading tests. The results of that will soon be available.