The article deals with military fortification constructions, their evaluation and field experimentation. Furthermore, it discusses legal standards, international and national regulations that set parameters and effects on military fortification structures. The diagnosis of structures can be characterized as a statement of differences between the assumed (projected) state and the current state of the examined structure. While field experimentation is an effect on structures and monitoring behavior and changes in the state of the structure. Considering the specific accidental actions, it is necessary to use diagnostic procedures other than conventional constructions, especially regarding the impossibility of breaking the structure by removing the specimen. It is necessary to evaluate the structure for a different type of action than usual. Some field tests were conducted at the Department of Engineer Technology according to STANG 2280. Some, however, were carried out according to their own procedure. These activities are referred to in the paper as field experiments and were used mainly to verify mathematical simulations of the behavior of actioned structures, and to make the experiments of field experiments more precise.