Impact Response Analysis of Reinforced Concrete Beam Under Falling Weight Impact Load

Abstract

Civil infrastructures all over the world are prone to natural disasters causing colossal damages. These natural disasters range from falling weight, avalanches and accidental loads to earthquakes, floods and tornadoes. In such situations, the structures undergo dynamic or impact loading, which are difficult to ascertain in behavior and quantum. In recent years, the risk of impact events on civil infrastructures has become of increasing concerns. Constructing civil and commercial infrastructures capable of sustaining impact loads with acceptable damage has gained a lot of attention. Impact Load is a relatively large dynamic load applied to the structure or part of it over a very short period of time. In this research the performance of reinforced concrete beam under the effect of direct impact loads is studied. Numerical simulation of the impact phenomenon is developed and presented in this thesis. Nonlinear model was developed on numerical code (LS-DYNA) for a reinforced concrete beam under falling weight impact load. From this study, it is seen that the time histories of impact force, reaction force and mid-span displacement can be predicted accurately by using the proposed FE analysis method. These results are based on two theories i.e von-mises theory and drucker-pragar theory. These results are verified against the experimental results of a previous study done in Japan. The effect of type of concrete based on its compressive strength is also analyzed in this thesis. The right choice in selecting concrete will not only increase the strength but also reduce the dead weight of the structure hence making it more economical. Further the modeled beam is scaled to generalize the results for real world scenarios using two basic theories i.e MLT and Calladine.