STRESS-STRAIN STATE OF RECONSTRUCTED CONCRETE ELEMENTS UNDER BENDING AND TWISTING DURING DYNAMIC LOADING

The article considers the behavior of reconstructed reinforced concrete elements, which simultaneously experience bending and torques when exposed to dynamic loads. The paper focuses on the importance of taking into account the complex stress state of structures under conditions of emergency and man-made impacts. Experimental approaches (pulse load tests, crack monitoring) based on tests of 108 reinforced concrete beams, as well as theoretical methods (elastoplastic modeling, finite element analysis) based on 4 mathematical models aimed at a comprehensive assessment of the strength and deformability of the elements are described. The limited research related to multiple dynamic loading, as well as the lack of reverse engineering tasks, is noted. Modern calculation methods, mainly used for static effects, are analyzed, and the need for their adaptation for the analysis of dynamic conditions is indicated. A comprehensive methodology using modern testing facilities and measurement systems is proposed, which makes it possible to increase the accuracy of the assessment and reliability by 7–9 % in comparison with existing methods for calculating the structures under consideration. The results contribute to the improvement of the design and operation of reinforced concrete structures in conditions of complex dynamic impacts.