A method and device for detecting the depth of cracks in reinforced concrete structures based on horizontal shear waves
A technology of horizontal shear wave and reinforced concrete, which is applied to measuring devices, processing detection response signals, and using ultrasonic/sonic/infrasonic waves, etc., which can solve problems such as rapid attenuation of compression waves, reduction of signal-to-noise ratio of detection signals, and inability to detect , to achieve the effect of low attenuation rate, high signal-to-noise ratio of detection signal, and improvement of detection accuracy
Active Publication Date: 2021-03-26
DALIAN UNIV OF TECH +1
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Problems solved by technology
[0003] Studies have shown that although the existing non-destructive testing methods for the depth of concrete cracks can detect cracks, the detection accuracy is often low, and it is usually impossible to detect when the cracks are deep
The main reason for the limitation of the existing method is that the existing method is based on the diffraction phenomenon of the compression wave at the end of the crack to detect the crack, and the compression wave attenuates quickly when propagating inside the concrete, and the compression wave will occur after diffraction at the end of the crack. Waveform conversion to generate other types of waves further reduces the signal-to-noise ratio of the detected signal
Moreover, the existing methods use a single sensor, which often requires multiple measurements to give a depth estimate, and the detection speed is too slow to achieve real-time detection.
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[0040] The specific implementation manners of the present invention will be further described below in conjunction with the accompanying drawings and technical solutions.
[0041] The detection data of a concrete bridge slab with a crack is used to verify the validity of the method, and the true depth of the crack is 94 mm.
[0042] The specific implementation is as follows:
[0043] (1) choose the intact area on the concrete bridge plate, utilize the device of the present invention ( image 3 ) for testing, it is necessary to ensure good contact between the wave source transmitting end of the equipment and the sensor receiving end, and to obtain the reflected wave of the slab bottom in the intact concrete area (see Figure 4 ), using the Hilbert transform to obtain the absolute amplitude information of the wave (see Figure 5 ), extract the reflected wave travel time from the absolute amplitude information, that is, the propagation time corresponding to the point where the ...
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The invention belongs to the technical field of nondestructive testing of civil engineering structures, and provides a reinforced concrete structure crack depth detection method and device based on horizontal shear waves. The method comprises the steps: firstly, detecting and obtaining the propagation speed of the horizontal shear waves in concrete in an intact area; secondly, carrying out detecting at the crack to obtain first arrival wave travel time after diffraction at the crack end; and calculating the crack depth by combining the measured wave velocity, the horizontal distance between the sensor and the transmitting end and the first arrival wave travel time after crack diffraction. A receiving end of developed equipment is provided with a plurality of sensors capable of simultaneously receiving a plurality of signals which are transmitted by the same wave source end but pass through different propagation paths, and an average value of crack depth is calculated by utilizing the plurality of signals detected once and is used as an optimal estimation value of once detection; and the accurate nondestructive testing method for the concrete crack depth is developed, and the methodhas important engineering significance for quantitatively evaluating concrete diseases and ensuring the use safety of the structure.
Description
technical field [0001] The invention belongs to the technical field of nondestructive detection of civil engineering structures, and provides a method and a detection device for crack depth detection of reinforced concrete structures based on horizontal shear waves. Background technique [0002] Concrete shrinkage, stress action, alkali-aggregate reaction, and improper maintenance can all lead to concrete cracking, which is a common disease in reinforced concrete structures in service. The development of cracks will accelerate the corrosion of steel bars inside the concrete, resulting in the reduction of structural bearing capacity and durability, and ultimately threaten the safety of the structure. Although the opening of concrete cracks is visible on the concrete surface, the openings are often too small to measure crack depth directly. Although the method of drilling samples at the cracks can accurately measure the crack depth, it will cause a certain degree of damage to...
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IPC IPC(8): G01B17/00G01N29/07G01N29/46
CPCG01B17/00G01N29/043G01N29/07G01N29/46G01N2291/011G01N2291/0232
Inventor林世镔王誉瑾
OwnerDALIAN UNIV OF TECH