Failure mechanism criterion for multiaxial strength of concrete after exposure to normal and high temperatures

Failure mechanism criterion is proposed based on comprehensive analysis of experimental phenomenon and micro/meso-mechanism of concrete failure. The failure mechanism criterion can successfully predict the multiaxial strength of normal-strength concrete (NSC) and high-strength concrete (HSC) in other studies. The newly proposed failure mechanism criterion is further developed to include temperature dependences and a cubic function is adopted to describe the relationship between material constants and temperature in the failure mechanism criterion. Then, the temperature dependent failure mechanism criterion is applied to predict the multiaxial strength of NSC and HSC after exposure to normal and high temperatures (NHTs). Good agreement is observed between the predicted values and experiment results from other studies. For the purpose of comparison, the mean error of the failure mechanism criterion is calculated and compared with that predicted by Seow-Swaddiwudhipong criterion, Songs criterion and He-Song criterion. The calculation indicates that the mean errors of the failure mechanism criterion, Seow-Swaddiwudhipong criterion, Songs criterion and He-Song criterion are 4.18%, 7.65%, 12.66% and 16.32%, respectively. This suggests that the failure mechanism criterion can give a more reliable prediction for engineering applications.