Estimation of the load-bearing capacity of existing reinforced concrete structures by vibration method with determination of the neutral line position

The objective of this article is to develop the theoretical foundations for assessing the load-bearing capacity of structures using the vibration method, to establish the exact value of the position of the neutral line during the operation of reinforced concrete structures. The following methods were used in the study: mathematical modeling based on known theoretical expressions and comparison of the obtained results with experimental data. The paper considered structures with different levels of load-bearing capacity, namely a beam without defects, a beam with small cracks, and a beam with a main crack. The obtained experimental values of the residual height of the concrete cross-section and the height of the compressed zone quite accurately coincide with the data of mathematical modeling for these characteristics. The results obtained will allow us to approach the solution of the problem of theoretical justification of the vibration method of inspection of reinforced concrete structures, improve the methods of its implementation and improve the accuracy of the results obtained.