Issue 46

I. Shardakov et alii, Frattura ed Integrità Strutturale, 46 (2018) 383-390; DOI: 10.3221/IGF-ESIS.46.35 383 Investigation of the effect of cracks on the vibration processes in reinforced concrete structures I. Shardakov, A. Shestakov, R. Tsvetkov, I. Glot Institute of Continuous Media Mechanics, Ural Branch, Russian Academy of Science, 1, Korolev street, Perm, Russia shardakov@icmm.ru, shap@icmm.ru , flower@icmm.ru, glot@icmm.ru A BSTRACT . The validity of the mathematical model describing the propagation of vibrations in the reinforced concrete structures (RC structures) was verified by comparing the experimental and numerical data. The proposed model allowed us to perform numerical experiments aimed at comparing vibrorecords obtained for the structure without defects and the structure with typical fracture caused by crack formation. Based on the results of comparison, an informative diagnostic parameter was proposed. This parameter makes it possible to control the nucleation and growth of cracks in a RC structure. K EYWORDS . Vibration-based diagnostics; RC structure; Cracks; Full-scale model; Experiment; Simulation. Citation: Shardakov I., Shestakov, A., Tsvetkov, R., Glot, I., Investigation of the effect of cracks on the vibration processes in RC structures, Frattura ed Integrità Strutturale, 46 (2018) 383-390. Received: 12.08.2018 Accepted: 22.09.2018 Published: 01.10.2018 Copyright: © 2018 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION he results of studies of the behavior of complex building structures under critical conditions are important for solving the problems of their safe operation. One of the modern approaches that make it possible to solve problems of safe operation of structures is the use of automated deformation monitoring systems. The most important components of these systems are mathematical models that adequately describe the operation of the structure in subcritical and critical stages of its deformation. The development and verification of such models is possible only when carrying out field experiments. For their implementation, a model structure was designed and assembled. This model reflects the deformation processes in full- scale engineering structure. It is a 4-storey monolithic reinforced concrete building on a scale of 1: 2 (Fig.1). Its total height is 6m, length is 9m, and width is 6m. Automated deformation monitoring systems are based on the non-destructive control methods, in particular, the methods of vibration diagnostics [1, 2, 3, 4], among which one can differentiate between the methods analyzing natural vibrations [5, 6] and those examining the transient vibration processes [7, 8]. The vibration methods have found wide application because of the use of piesoceramic materials, which can operate both as actuators and sensors. They allow fault diagnosis in a broad frequency range and can be installed at the surface of the examined structure [9, 10] or embedded into it [11, 12]. The proposed approach is based on the registration of vibration processes in the structure under the action of impulse loads. It allows us to perform the local analysis of separate fragments of the structure while tracing the evolution of the T