This paper presents the experimental and theoretical results of an investigation carried on reinforced concrete plates placed on yielding supports along their perimeter under short-term dynamic loading. The yielding supports are made of elements with annular cross-section. Their functionality allows operations in elastic and elasto-plastic stages with a further turning to hardening stage. This particular support scheme has been adopted in order to simulate the different boundary conditions that r.c. slabs subjected to impacts may encounter in practical applications of civil engineering (e.g. roofs, vertical panels, retaining walls, guardrails, etc.). The experimental results showed that influence of support deformability on the structural response under impact depends on their rigidity and on the deformation stage. The results of numerical simulations based on a simple mechanical model qualitatively agree with the experimental results. Therefore the model can be adopted for simulation and design of reinforced concrete panels under impact or high-strain loading situations.