Quick bridge impact coefficient determination method

Abstract

The invention discloses a quick bridge impact coefficient determination method. The quick bridge impact coefficient determination method includes the steps of firstly, recording vertical vibration speed signals of a girder on the bridge mid-span section when loaded vehicles run at different speeds; secondly, integrating the speed signals in a frequency domain after the speed signals are subjected to band-pass filtering noise-reducing processing, and subjecting the speed signals subjected to FFT (fast Fourier transformation) so as to obtain displacement time domain signals, namely a dynamic deflection curve of a bridge; thirdly, computing a maximum amplitude value ydmax of dynamic deflection according to the dynamic deflection curve obtained by integration; fourthly, determining a load arrangement mode of the loaded vehicles according to an analysis result on moving load of the girder mid-span section, and measuring a maximum static deflection value y0 of the girder mid-span section by testing; fifthly, computing bridge impact coefficients 1+mu=1+ ydmax / y0 at different vehicle speeds so as to obtain a maximum impact coefficient value finally. The quick bridge impact coefficient determination method has the advantages that measurement of the maximum dynamic deflection value ydmax and the maximum static deflection value y0 of the bridge mid-span section can be achieved by simply obtained low-frequency vibration pickups (speed sensors) and level gauges respectively, and then the impact coefficients of the bridge mid-span section at different vehicle speeds are obtained.

Description

technical field [0001] The invention belongs to the field of bridge structure detection in civil engineering, and in particular relates to a method for quickly measuring the impact coefficient of a bridge. Background technique [0002] The bridge impact coefficient refers to the increase coefficient of the vertical dynamic effect on the bridge span structure when the vehicle crosses the bridge. The detection of bridge impact coefficient has extremely far-reaching significance for bridge design, maintenance and reinforcement. If the impact coefficient of bridge structure cannot be accurately detected, it will lead to unreasonable design of new bridges or untimely maintenance and reinforcement of old bridges, which will cause bridge damage caused by vehicle loads. , When it is serious, a major accident also occurs, causing the loss of people's lives and property. The detection of bridge impact coefficient is an important aspect of bridge dynamic response measurement, which ca...

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Problems solved by technology

[0005] The present invention aims at the existence of an electric displacement meter in the prior art that can directly measure the moving displacement, but it needs to be installed on a stationary floor support, which requires higher requirements under the bridge, and is difficult to realize in many places; although the photoelectric deflection meter does not need a fixed Floor support, but it is very inconvenient to install a prism at the bottom of the mid-span, and the equipment is expensive and not conducive to popularization. A method for quickly measuring the impact coefficient of bridges is proposed

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