Numerical Simulation of Consecutive Rockfall Impacts on Reinforced Concrete Slabs

The risk due to falling rocks in Alpine regions is managed by means of various protective structures. Rockfall protection galleries are one of the common types of these structures built to protect the human lives and transportation network. In order to establish a rational method to improve the design of rockfall protection galleries, large-scale tests have been carried out in Switzerland.

Reinforced concrete slabs were subjected to repeated falling-weight impacts with increasing falling height.

The current work presents finite element modeling of some of these tests and the results are compared to the experimental data. Calibrated with the experimental data, finite element analysis provided a reasonable extension of the test results. This facilitates understanding the behaviour of rockfall protection galleries subjected to impacts of more than one rock in their history. Based on the numerical investigation, a comparison was made between the response of a slab subjected to consecutive impact loading and virgin slabs subjected to similar impacts. For the range of the modeled experiment, it was observed that the maximum reaction force of the slab was reduced up to 25% due to the softening of the slab and its cracking. With virtue of the comparison made based on residual deflections, numerical extension of this study may help investigating the extent of damage to the existing structures which have already sustained one or more impacts during their service life to provide a sustainable decision making for their maintenance and strengthening.