Parametric study of RC beams under a wide range of loading rates

Abstract

Over the years, numerical investigation has been presented as a viable alternative to experimental studies, as testing of structural members to assess the effect of several parameters at a time is not only cumbersome but also expensive. Thus, after validating the results from a finite-element analysis with experimental outcomes, a numerical parametric study was conducted to investigate the effects of various parameters on the dynamic increase factor (DIF) of the maximum resistance and the failure mode of reinforced-concrete beams under a wide range of loading rates. From the results, it can be concluded that the DIF of maximum resistance for beams with a small amount of longitudinal reinforcement is greater than that for beams with a large amount of longitudinal reinforcement. A change in the failure mode can be observed (mainly at high rates, 2 m/s) when the longitudinal reinforcement ratio is increased (approaching the balanced-reinforcement ratio) in an under-reinforced beam. For beams with a large amount of transverse reinforcement, the DIF would be lower than for beam with a small amount of transverse reinforcement. Furthermore, it was found that the yield strength of longitudinal reinforcement is the key parameter affecting the failure mode change from flexure at static loading to shear at high loading rates.