Abstract:
Natural disasters are events that cause immense damage and sufferings which happen unexpectedly. To mitigate the damage to infrastructures due to natural disasters such as avalanches, falling rocks, earthquakes and Blasts; a rational performance based impact-resistance design procedure should be established to cater for above circumstances. To accomplish this, it is necessary to establish correct method of evaluation for each limit state; mainly Serviceability and Ultimate Limit States. Therefore, in order to apply the prediction method for the practical design of anti impact reinforced concrete girders, the applicability of method should be confirmed by conducting field tests using prototype reinforced concrete girders. However these tests besides being uneconomical and unpopular because special techniques are required for setting up the experiment and measuring the dynamic response time histories of the girders. Therefore, it is of great practical importance to establish a rational numerical analysis method for investigating dynamic response behavior of the structures under impact loading.
This study will be focusing on a proposed 3D FE Analysis method of small scale reinforced girder under falling weight impact method by applying simple constitutive model of concrete element. In an elasto-plastic impact response analysis, two types of cracking model have been established. These are the discrete cracking model and the smeared cracking model. In discrete cracking model double nodal points are required in the region where cracking is developed while in smeared cracking model only compressive force will be transferred in the element on cracking. This research will establish a rational 3D FE analysis method for accurately evaluating the dynamic response characteristics of prototype reinforced concrete structures under impact loading and determines time history of impact force, reaction force, displacement, hysteric loops of impact force-displacement and reaction force-displacement and crack pattern on the girder surface by using LS-DYNA code.
