Damage Mechanisms of a Reinforced Concrete Rock-Shed Slab Impacted by Blocks

In mountainous areas, accidental rock falls are common hazards, which can cause a lot of damage. The passive protection systems of roads are usually rock-shed galleries composed of reinforced concrete elements. In this paper, a new type of structure is presented. The main innovation, compared to conventional solutions, is to dissipate the impact energy directly into the reinforced concrete slab or into fuse supports, and no longer into a cushion layer. The dynamic phenomena, taking place during the impact of a block onto the slab, are analyzed by means of experiments on a one-third-scale model (slab of 12 m×4.80 m×0.28 m) of a real structure. The results made it possible to validate the operating and repair principles of the structurally dissipation rock-shed and revealed that the slab is damaged by three main mechanisms: punching, bending, and surface level breaking below of the impacted zone. These three damage modes are analyzed by means of data resulting from the various experimental tests.