The aim of the Research Training Group GRK 2250 funded by the German Research Foundation is interdisciplinary research to increase impact resistance of existing structures by strengthening. The article at hand provides insight into research at structural level. Mineral-bonded strengthening layers were investigated on the face of the structure which was not hit by impactor. As material for these layers, fine-grained matrices without and with short fibres were used. Their effectiveness was varied by embedding different textiles. Strengthened reinforced concrete plates were subjected to impact loading in a drop tower facility. An important indicator for the effectiveness of strengthening is the degree of damage. For this purpose, a method for the analysis of crack patterns by means of image sequence analysis was developed. Furthermore, the experiments serve as a reference for the simulation of crack propagation in the strengthened plates by the phase field method.