On the Probability of the Development of the Diagnostic Feature of Decline the Bearing Capacity of Structures under Random Dynamic Loads

Abstract

The article is devoted to the problem of identifying the diagnostic feature of the structure bearing capacity decrease under random dynamic loads. The diagnostic features that characterize the decrease of the bearing capacity of structures and foundation are identified. The model of the dynamic system that describes the process of the diagnosed building structure functioning is presented. The article shows the difficulties encountered in the process of vibration diagnostics of reducing the bearing capacity of structures and foundations. It is pointed out that the output vibration signals can be recorded in the mode of displacements, velocities and accelerations. But at the same time, the probability spread of detection of diagnostic feature of the bearing capacity decrease of building elements in the energy spectra of the output vibration signals can be significant. To develop a method for determining this probability, the authors propose to use a regression analysis with the solution of the problem at three levels of “regression”. In the article the factors influencing the probability of detection the vibration diagnostic feature in bearing capacity decrease of building elements are analyzed. This probability characterizes the effectiveness of the vibration diagnostic method in monitoring systems of unique objects, including launch facilities. The authors have shown that the maximum efficiency is achieved by using systems for monitoring energy spectra of vibration accelerations at the output. At the same time, the authors conclude that the probability of effective functioning of vibration diagnostic systems is mainly influenced by such factors as the sensitivity of the vibration diagnostic method to the rigidity decrease of structures and bases. The equipment error of registration of the energy spectra of vibration accelerations is also to be taken into consideration