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Main gas pipelines are critical engineering structures, and, therefore, their safe operation is an urgent scientific and technical problem. This paper describes a series of experimental studies conducted in one section of an actual main gas pipeline. The goal is to analyze oscillatory wave processes taking place in a gas pipeline in response to various external effects, such as impact loads applied to the ground in the vicinity of the pipeline, operation of the stop valves (valve switching from the full open to full closed position, or vice versa), and gas release through the holes of different diameters simulating the appearance of a fistula in a pipeline wall. Based on the obtained experimental results, the specific features of the propagation of oscillatory processes are established, and the conditions of a possibility of recording these processes by fiber-optic accelerometers are determined. [ABSTRACT FROM AUTHOR]

This paper presents an efficient approach to detect crack generation in reinforced concrete structures by vibration monitoring. Our study uses ambient background vibrations to induce vibrations in the structure. Registration of crack nucleation and propagation is based on the analysis of changes in the eiegenfrequencies of structural elements. The constant response of structural elements to background vibrations makes it possible to organize the on-line monitoring of cracks. Mathematical modeling of deformation processes in the structure serves to determine the magnitude of the shift in eigenfrequencies under different cracking scenarios, to identify vibration modes most sensitive to cracking, to find optimal locations of vibration sensors and to define the required registration accuracy. In the experiments, the response to the traffic-induced vibrations was registered at 6 points of the structure. [ABSTRACT FROM AUTHOR]

The paper presents an automated system for monitoring the deformation state of a building complex. The measurement unit of the system records the vertical displacements of a number of bearing columns using the hydroleveling method. In the analytical block, numerical modeling of deformation processes in the subsoil–foundation– building system is performed. The information on the foundation settling obtained during monitoring is used to specify the boundary conditions for modeling the stress-strain state of the structure. Thus, the deformation response of all structural elements to uneven vertical settling of supporting columns is evaluated. The monitoring system has been working since 2010 and it has demonstrated high efficiency. [ABSTRACT FROM AUTHOR]