Middle and small bridge fast detecting method based on long-scale-distance optical fiber strain sensor

A technology of optical fiber sensors and small and medium bridges, applied in the testing of machines/structural components, measuring devices, vibration testing, etc.

Active Publication Date: 2014-12-10
SOUTHEAST UNIV
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  • Description
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  • Application Information

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  • Middle and small bridge fast detecting method based on long-scale-distance optical fiber strain sensor
  • Middle and small bridge fast detecting method based on long-scale-distance optical fiber strain sensor
  • Middle and small bridge fast detecting method based on long-scale-distance optical fiber strain sensor

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Embodiment 1

[0060] by figure 1 The shown cantilever beam structure is taken as an example, and the specific implementation manner of the present invention will be described in detail.

[0061] 1. Divide the structural units, arrange long-gauge fiber optic sensors on the units, select appropriate nodes to load the impact force and record the impact force and dynamic strain time history data at the same time, and calculate the strain frequency response function from the recorded time history data.

[0062] The structure is divided into several units according to the length of the force-bearing member where the long gauge fiber sensor needs to be arranged. In this embodiment, the length of the cantilever beam in the cantilever section is 1.6m, and the long gauge fiber sensor is used to measure the gauge of the part. The pitch length is 0.2m, so the structure of this embodiment is divided into 8 units, and the units are numbered as unit 1 to unit 8 from the fixed end to the cantilever end, an...

Embodiment 2

[0074] Figure 10 An example of a three-span simply supported reinforced concrete girder bridge is shown. The main girders on both sides of each span are key structural components, so long-gauge fiber optic sensors are arranged on their bottom layers. Then, impact force was applied to different positions of the bridge deck for vibration test, and the time history data of impact force and dynamic strain were recorded. First, the strain frequency response function of each span bridge is estimated by the impact force and macro strain observed in the vibration test, then the calculated modal parameters, especially the scaling coefficients of each mode shape, and then the overall structure is calculated by the formula (9) Strain compliance. Finally, the strain of each element of the bridge under any static load is predicted by the strain compliance. Figure 11 It is shown as the strain value of each unit of the main girder on both sides of the first span of the three-span simply...

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Abstract

The invention discloses a middle and small bridge fast detecting method based on a long-scale-distance optical fiber strain sensor. The method includes: arranging the long-scale-distance optical fiber strain sensor on the surface of the main stress component of a middle and small bridge, loading impact force to perform impact excitation on a bridge deck, and by the optical fiber senor, recording the time course data of bridge dynamic strain during impact excitation and recording the time course data of the impact force at the same time; identifying to obtain the structural strain flexibility matrix in the structural strain flexibility according to the obtained time course data of bridge dynamic strain and the impact force. The method has the advantages that the method is different from processing methods, which mainly aims at acceleration data, in documents, the method aims at the measured long-scale-distance dynamic strain and specifically researches strain flexibility identification based on long-scale-distance strain measuring, structural strain flexibility can be identified by measuring long-scale-distance dynamic strain under impact vibration so as to perform structural safety evaluation, and the method is the first method aiming at strain flexibility identification in China.

Description

technical field [0001] The invention is a rapid detection method for small and medium-sized bridges based on a long-gauge optical fiber strain sensor in the field of civil engineering and transportation, which can realize timely and accurate safety assessment of small and medium-sized bridges to avoid bridge collapse and other accidents. Background technique [0002] The performance of civil engineering structures such as bridges gradually degrades under the natural environment and service loads, and they may be attacked by strong natural disasters such as earthquakes and typhoons at any time. Therefore, regular testing and diagnosis of civil engineering structures can effectively reduce the possibility of structural collapse and avoid disasters. In recent years, structural health monitoring and diagnosis technology based on vibration testing has been gradually applied to civil engineering practice. [0003] Acceleration is a structural response often measured in civil engi...

Claims

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Application Information

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IPC IPC(8): G01M7/02G01M7/08
Inventor 张建吴智深郭双林李攀杰
Owner SOUTHEAST UNIV
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