Scheglova

This article deals with the problem of marker determination; these markers allow to locate hidden fractures in individual bridge spans. The frequency method for investigation of oscillation in systems with distributed parameters was used for the analysis. A known mathematical model – the model of pin-ended beam with point load - was used because additional weight would lead to the decrease of the main natural frequency, just like a fracture would do in this place. The decision analysis of the wave equation allows to identify dependences of changes in the first six frequencies subject to the place of critical section. A set of values of frequency reducing on different harmonic components could be regarded as an attribute of the critical section area. This conclusion may be of significant practical importance when analyzing results of bridge monitoring.

The author considers the problem of localization of a hidden fracture in a bridge span, basing on the experimental data analysis. Monitoring system, which allows to record spectrums of natural frequencies of certain spans of a bridge, was developed at the “Apparatuses and systems of orientation, stabilization and navigation” department of BMSTU. It was shown in the article that analysis of fractional variation of the first six frequencies of each span of a bridge makes it possible to localize the critical section.