ABSTRACT
This paper reviews the effects of loading rate and stress level on concrete strength and elastic modulus as it pertains to the regression of rapid load test data. Based on detailed laboratory research, a stress-strain-strain rate relation is developed then normalized for application to various concrete mix designs. The model is validated for two field tests. For long piles subjected to significant amounts of side shear, it is concluded that the non-linear behavior of concrete must be taken into account for a proper interpretation of load distribution. A practical method is presented herein.
