To study the response of a RC cantilever beam subjected to impulse excitations is based computational model. Static and dynamic analysis of the computational model was performed using a software product based on the Finite Element Method. Two numerical models have been builded for static analysis. In the first model, the concrete modelled with a linear - elastic material model and the reinforcement as deformable bars. In the second model, the concrete modelled using a nonlinear model of concrete - the material model of Willam and Warnke, and the reinforcement as deformable bars. For dynamic analysis, concrete modelled as a linearly elastic material and reinforcement as deformed bars. Under impulse loading, the applied force acts for a very short but limited time interval. This article presents five cases of impulse duration. The dynamic time-history analysis used to determine the dynamic response of the RC cantilever beam under the action of time variables. This type of analysis used to determine time-varying displacements, stresses, and internal forces caused by a combination of static and dynamic (pulse and harmonic) loads. A dynamic time-history analysis used to study the dynamic response to time-varying loads. The time-determined displacements, deformations, stresses and internal forces give the behaviour and reaction of the structure at any time in the studied interval.