Experimental and Theoretical Study of Rockfall Impacts on Concrete Slab under Low-velocity Impact

Concrete bridges often undergo the influence of windborne/waterborne debris, vehicle/vessel collision, and rockfall because of frequent seismic activity. Damage due to rockfall impact can influence the properties of the concrete structures and should be considered while investigating the mechanical behavior of a designed structure. In this study, experiments on concrete slabs were conducting by subjecting them to impact velocities ranging from 3.16 to 7.74 to understand the failure of concrete slabs under the low-velocity impact. The length-to-thicknesses (L/T) ratios of the slabs were 12.5:1 and 6.25:1, respectively. A high-velocity camera was used to record the entire process of crack occurrence, development, and destruction in each target slab during the impact process. The failure mechanism and crack distribution in the targets were obtained through the experiments. Assuming that elastoplastic deformation occurred in the slabs and considering the overall deformation characteristics, a method for the calculation of rockfall impact force was developed. Furthermore, a numerical model with a large geometric size was established to simulate and compare impact responses and the maximum impact force. The calculated results have corresponded to the the experiment and analysis.