Fatigue behavior and cumulative damage rule of concrete under cyclic compression with constant confined stress

摘要

The effects of different lateral confinement stress on the fatigue behavior and cumulative damage of plain concrete were investigated experimentally.Eighty 100mm x 100mm x 100mm specimens of ordinary strength concrete were tested with constant-or variable-amplitude cyclic compression and lateral confinement pressure in two orthogonal directions.A fatigue equation was gained by modifying the classical Aas-Jakobsen S-N equation and used for taking into account the effect of the confined stress on fatigue strength of plain concrete.The present study indicates that the fatigue failure is greatly influenced by the sequence of applied variable-amplitude fatigue loading,and Miner' s rule is inapplicable to predict the residual fatigue life,especially in the sequence of low to high.The present research also shows that the exponent d of the Corten-Dolan' s damage formula is a constant depending on the materials and the levels of load spectrum,and d can be determined through the two-stage fatigue tests.The residual fatigue lives predicted by Corten-Dolan' s damage formula are found to be in good agreement with the results of the experiments.