CRACK RESISTANCE OF BRIDGE REINFORCED CONCRETE STRUCTURES BASED ON THE FRACTURE MECHANICS PRINCIPLES

Abstract

Purpose The work purpose is to establish the real technical condition of reinforced concrete and steel-reinforced concrete bridges based on the surveys and tests, as well as the analysis and synthesis of scientific and technical sources. Methodology. To achieve the goal, a review and synthesis of scientific and technical sources and regulatory documents regarding the technical condition of reinforced concrete and steel-reinforced concrete bridges and overpasses of Ukraine is carried out. It is shown that the development and implementation of new technologies for repairing the existing bridge defective structures, in particular on the highways of Ukraine is an urgent problem. A thorough analysis of experience and publications on the operation of newly built and long-term specified bridges in the mentioned environments is carried out. The data on the main unacceptable defects and faults of bridge structures as well as the causes, including concrete and reinforcement corrosion, and other defects and faults are presented. The quality indicators of reinforced concrete and steel-reinforced concrete bridge structures are considered, the problems and analysis of ensuring reliability and durability in the operation conditions on the highways of Ukraine are formulated. Results. The analysis of domestic and foreign scientific and technical sources as well as the experience of surveys and tests regarding the technical condition of reinforced concrete bridges structures in Ukraine is carried out. In particular, the analysis and synthesis of the problems of ensuring the reliability and durability of the specified bridges in the operation conditions on the highways of Ukraine is carried out. The design errors, construction defects and faults, and long-term operational faults in the mentioned environments are summarized and clarified. In addition, the obtained data are as the basis to specify the criteria and models of the destruction mechanics in relation to reinforced concrete bridge structures. In particular, based on the obtained data, the methods to determine the VAT and the residual resource of the specified bridges are created. Scientific novelty. Based on the analysis and synthesis of scientific and technical sources and a number of surveys and tests, reinforced concrete and steel-reinforced concrete structures and long-term bridges newly built after the floods in 1998 and 2001, it is possible to summarize the main reasons that significantly affect the structures degradation of both the newly built and long-term bridges. This allows generalizing the design errors, construction defects and faults, and long-term operational faults. In addition, the state data served as the basis to specify the criteria and models of the destruction mechanics in relation to reinforced concrete bridge structures. In particular, based on these data, the methods to determine the assessment of the strength and crack resistance and the VAT and the residual resource of such bridges are created. Practical significance. Based on the given data and observations of real objects for 30 years, the main faults, defects and errors of the design, construction, and long-term bridges are summarized and set up. The methods to determine the VAT and calculate the residual resource, giving an opportunity to work out the repair and restoration method to increase the durability and reliability of long-term bridges are created.