Abstract
Need of use of mobile measuring computer systems when performing diagnostics of bridges is shown and also the analysis of amplitude-phase-frequency characteristics frame reinforced concrete and metal flying structures of railway bridges is provided at the movement of the train. This in turn allows to estimate conditions of span structures by width of ranges in points of half energy of spectral curve in the area of resonances. Assessment of technical condition and diagnostics of supported artificial structures is carried out according to dynamic parameters. According to this method frequency of natural oscillations is determined from peak values of averaged spectral densities of reduced power. Comparing width of the received ranges to ranges of the new (intact) flying structures it is possible to estimate degree of wear and a damage rate of elements of designs. Based on the results of the calculations, it has been confirmed that the inclusion of elements of the bridge web and the upper structure of the track in the joint work with the main bearing structures increases the accuracy of solving the problem of determining natural frequencies.