Introduction. Researched methods of accounting for the nonlinear operation of reinforced concrete structures on the example of an industrial structure, when exposed to an air shock wave using modern software systems based on the finite element method. The calculation of reinforced concrete construction to the impact of an air shock wave, if no increased requirements for tightness are presented to it, in accordance with current regulatory documents, must be carried out taking into account the elastic-plastic work, crack opening in the stretched zone of concrete and plastic deformations of reinforcement are allowed. Reviewed by new coupling approach to determining the dynamic loads of a shock wave, implemented in the LS-DYNA software package, which allows to take into account the effects of a long-range explosion and wave-wrapping around a structure. Materials and methods. The study of the stress-strain state of the structures was carried out using numerical simulation. For the nonlinear equivalent-static method, a step-by-step calculation algorithm is used, with gradual accumulation and distribution of stresses, implemented in the LIRA-SAPR software package. For the nonlinear dynamic method, the Lagrangian-Eulerian formulation is used using the methods of gas dynamics in the LS-DYNA software package. Results. As a result of numerical simulation, the following was done analysis of existing methods of nonlinear calculations; analysis of the existing loads during the flow of shock waves around the structure; analysis of the forces and movements in the bearing elements, as well as pictures of the destruction of concrete and reinforcement. Conclusions. According to the results of the comparison of the two approaches, conclusions are drawn about the advantages and disadvantages of the methods. Advantages of nonlinear dynamic calculation methods are noted compared to the equivalent-static ones. Use of the combined approach to the description of the shock wave front gives a reduction in time and allows us to describe the interaction of the wave with the structure with sufficient accuracy. The findings indicate the relevance of the study and provide an opportunity to move to more reasonable computational models.

The analysis shows that the parameters of the air shock wave vary significantly and have a pronounced random nature. In general, in structural analysis, design parameters of the shock wave are random functions or random variables; therefore, the reaction parameters of the system under consideration will also be random. Then, fulfillment of certain conditions (for example, strength) is only possible with a certain probability, and the reliability of the system under consideration can be estimated using methods of building structures reliability, methods of mathematical statistics and probability theory. As a result, a probabilistic model of an air shock wave has been developed and the reliability of a free-standing wall has been estimated for random exposure parameters, as well as for random strength characteristics of materials. Based on the calculation results, it was concluded that the calculation of reliability using methods of mathematical and statistical probability theory makes it possible to bring the strength analysis of building structures closer to actual operating conditions.

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Modeling of the impact of a point explosion shock wave on a soil mass and an underground structure at different locations of the explosion epicenter from the ground surface was performed. The study of the stress- strain state of soils was carried out usi ng a nonlinear dynamic method and a fully coupled numerical model, in­cluding various models of materials. The result of numerical modeling showed the adequacy of the adopted nu­merical calculation methods. The findings showed that solving the problem in a nonlinear dynamic formulation allows obtaining the parameters of the shock wave at different depths from the explosion center, as well as ob­taining a complete picture of the interaction of the shock wave with the underground structure in surface and un­derground explosions.