Elasto-Plastic Dynamic Responses of Reinforced Concrete Slabs under Rockfall Impact

The process of rockfall impact on reinforced concrete slabs is accompanied by complex energy transformation. The traditional engineering design, which was based on experience or the Hertz contact law, has great deviation with actuality. In order to develop an efficient and accurate calculation method of rock-fall impact response, we adopted dynamic equations proposed by Olsson for orthotropic composite plates under impact loads, meanwhile compared the dynamic responses calculated according to the elasto-plastic contact law, the Hertz contact law and the dynamic finite element method. The results show that, in the same conditions, as the plastic deformations of slabs were considered in the Hertz solution, its peak contact force was larger than the elasto-plastic solution and dynamic finite element solution by 31.8% and 77.1% respectively. Moreover, the maximum indentation derived from Hertz solution was increased by 17.3% and 61.8% than the elasto-plastic solution and dynamic finite element solution, respectively. The elasto-plastic dynamic responses were closer to the dynamic finite element solutions than Hertz dynamic responses, demonstrating that the proposed elasto-plastic method is efficient and accurate without complicated modeling process.