Analysis of Dynamic Parameters of a Railway Bridge

Abstract

This article analyses the dispersion of vibration accelerations of a railway bridge during the passage of a train, and presents an analysis of their parameters after the application of the theory of covariance functions. The measurements of vibration accelerations at the fixed points of the beams of the overlay of the bridge were recorded in the time scale as digital arrays (matrices). The values of inter-covariance functions of the arrays of data of measurements of digital vibration accelerations and the values of auto-covariance functions of the individual arrays, changing the quantization interval in the time scale, were calculated. The compiled software Matlab 7 in the operator package environment was used in calculations. This article aims at determining the interdependencies of results of vibrations of bridge points rather than at the impact which a train makes on a bridge without emphasizing the modal parameters of the bridge. The aforementioned interdependencies make it possible to predict the results of hard-to-reach points.

The Influence of Different Loads on the Footbridge Dynamic Parameters

“…The use of the monitoring data allows to confirm that the existing bridges can withstand increased load conditions; monitoring experience also allows improving mathematical models and the design of structures of future bridges. Some of the latest research and experiments are presented in the literature [2][3][4][5][6][7].…”

“…Since footbridges have been relatively slender structures, they are sensitive to dynamic loading. Road and railway bridges are exposed to high speeds and magnitudes of loading [2], while in the cases of footbridges, load translates slowly (pedestrians) but it can result in a harmonic excitation; in both cases, dynamic excitation can cause relatively high displacements and deformations [3].…”

“…Accelerometers 8344 (Figure 3b, measuring range of ± 2.6 g, a sensitivity of 2.5 V/g and 0.176 kg of weight) were arranged on mounting blocks that guaranteed proper orientation and attachment. The detailed description of this equipment (Figure 3a, LAN-XI Data Acquisition Hardware Type 3660 with 3-modules: one 3160-B-042 and two 3050-B-060) was presented in the authors' works [2]. Two types of measurements were performed in the experimental studies-the OMA (Operational Modal Analysis) was performed in the first case; the measurements were made of the bridge points at different external loads in the second case.…”

Force and Sound Pressure Sensors Used for Modeling the Impact of the Firearm with a Suppressor

“…The apparatus for measuring the sound pressure is shown in Figure 4d. This part depicts an audio analyzer with a microphone 2250 and a hydrophone 8103 [90,91]. During the research, the dynamic effects of a bullet caused by a silencer are examined.…”

“…The apparatus for measuring the sound pressure is shown in Figure 4d. This part depicts an audio analyzer with a microphone 2250 and a hydrophone 8103 [90][91][92]. The received measurement signals from the computer were processed using static data processing package Origin 6 and Pulse software packages.…”