Complex analysis and evaluation of the condition of reinforced-concrete components in power-generating structures

Abstract

A procedure is proposed for analysis of reinforced-concrete slabs and shells.At the present time, priority significance is given to the problem of enhancing the reliability and safety of powergenerating structures [Russian Federation Law "On the safety of water-development works," HP-001-97 "General positions of safety provision at nuclear power plants (OBP-88/97, and other regulatory documents requiring failsafe provision for their operation]. This approach is fundamentally distinguished from approaches and trends of the previous period, which were directed toward universal economy of construction materials, including savings generated in an incompletely substantiated reduction in safety factors. The significant volumes of basic power-generating structures are composed of massive reinforced-concrete components. Since damages, premature shutdown, and failures of highliability structures and components may lead to catastrophic consequences, and be accompanied not only by significant material losses, but also human victims, solution of problems relative to reliability and safety enhancement on the basis of complex analysis and evaluation of the condition of the reinforced-concrete components assumes major significance.The complexity of analysis and evaluation of the condition of reinforced-concrete structures suggests visual and instrument inspections with the drilling of cores, experimental determination of physico-mechanical characteristics of the concrete and reinforcement, evaluation of the effect of exposed cracks, and check calculations with consideration of the actual condition of the structures. To refine methods of analysis, it is necessary to perform model investigations of the components of reinforced-concrete structures.Qualified specialists of the Scientific and Technical Center for Structures, Components, and Construction Materials (STC SCCM) propose unique equipment and instruments, and modern software for implementation of an entire set of studies for analysis and evaluation of the condition of concrete structures and reinforced-concrete designs.Basic trends in the activity of the STC SCCM are: 1. Inspections of concrete and reinforced-concrete designs of any power-generating, industrial, and civil structures with evaluation of their condition and development of recommendations for a repair and reconstruction strategy (laboratory for field inspections of structures at nuclear and hydroelectric power plants, headed by M. V. Frolov).The laboratory conducts a large set of field inspections of reinforced-concrete components of the Kura and Smolensk nuclear power plants (NPP), and depositories. In connection with the expiration of the standard service life for structures at nuclear plants (30 years), these investigations have made it possible to evaluate the actual condition of in-service structures, and the possibility of continuing their operating time to shutdown for an extended period. A patented method of determining the stress state of the concrete and reinforcement using resistance-type strain gag...

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