Improvement of Spectral Analysis of Free Oscillations of Load-Bearing Beams of Metal Bridge Spans

Abstract

The spectral analysis of free vibrations of bridge spans is an important tool to evaluate their dynamic characteristics and technical condition. The analysis oscilloscope patterns recorded during the impact, allows identifying the main frequency components and energy characteristics of the vibration process.
Purpose: The aim is to analyze the transformation of input signals recorded by measuring devices and structural responses in the form of free vibrations and investigate statistical characteristics of their spectral parameters.
Methodology: The spectral analysis was performed for oscilloscope patterns of free vibrations of metal bridge spans obtained under laboratory and field conditions. Segmental spectral analysis and a probabilistic approach allow to estimate the spectral power distribution and identify the dynamic behavior of beams.
Research findings: It is found that the energy spectrum of vibrations contains several narrow frequency bands, among which there are the main energy-carrying regions. The range of natural frequencies and their damping parameters are determined. Practical implications: Research results can be used in diagnosis and monitoring of the dynamic state of bridges based on the analysis of their vibration characteristics.