Author(s)

N. Madjlessi, D. M. Cotsovos

Abstract

The effect of the loading-rate on the dynamic response of reinforced concrete members under impact loading is investigated numerically through the use of three-dimensional dynamic nonlinear finite element analysis. The package employed is capable of realistically accounting for the triaxiality and the brittle nature characterising concrete material behaviour as well as the characteristics of the problem at hand, a wave propagation problem within a highly nonlinear medium. Due to the availability of tests data, the present study focusses on investigating the effect of impact loading on the behaviour of reinforced concrete beam specimens. The numerical predictions obtained provide detailed insight into the mechanisms underlying RC structural response and offer a quantitative description of the effect of loading-rate on certain important aspects of the exhibited behaviour. Based on the numerical predictions obtained, a physical model is proposed which is capable of realistically describing the behaviour of the RC structural elements under high rates of concentrated loading. The proposed physical model links the observed shift in structural response to the localised experimentally established and/or numerically predicted behaviour with increasing rates of applied loading. Its formulation is based on the use of the Compressive Force Path method which is capable of realistically describing the behaviour of a wide range of reinforced concrete structural configurations at their ultimate limit state under both static and seismic loading conditions.

Keywords

reinforced concrete, impact, loading rate, compressive force path method, finite elements, nonlinear dynamic analysis