A method for testing the void defects of steel box concrete shear wall

Abstract

The present invention provides a method for testing the hollowing defects of steel box concrete shear walls, comprising: using an ultrasonic method to conduct a large-area measurement of steel box concrete shear wall components, determine the suspected hollowing defect area, and mark the suspected hollowing defect area; laying a plurality of piezoelectric sensors on the outer surface of the steel box concrete shear wall components to accurately detect the area of ​​the suspected hollowing defect area; using a temperature detection method to detect the hollowing depth of the suspected hollowing defect area. The method for testing the hollowing defects of steel box concrete shear walls provided by the present invention provides technical support for quantitative detection of steel box concrete shear walls through ultrasonic methods, piezoelectric sensors and infrared temperature testing methods, and provides a safety assessment means for the use of steel box concrete shear wall components.

Description

Technical Field

[0001] The invention relates to the technical field of nondestructive testing, and in particular to a method for testing hollow defects of steel box concrete shear walls. Background Art

[0002] Sound waves are mechanical waves with a frequency higher than 20 kHz. The frequency commonly used in ultrasonic flaw detection is 0.5 to 10 MHz. This mechanical wave can propagate in a material at a certain speed and direction. When it encounters a heterogeneous interface with different acoustic impedance (such as a defect or the bottom surface of the object being tested), it will produce reflection, refraction and waveform conversion. The defect location can be determined based on the received sound wave parameters.

[0003] The piezoelectric driver receives an electrical signal to generate an inverse piezoelectric effect, which applies a load to the structure and generates a stress wave. The stress wave propagates through the structure and reaches one or more piezoelectric sensors. The piezoelectric sensors receive the stress wave signal and generate a positive piezoelectric effect to convert the mechanical vibration signal into an electrical signal. The electrical signal is collected by a dynamic data acquisition system, and then the signal parameters such as the amplitude, energy, phase, spectrum and waveform of the received signal are analyzed by a computer storage and calculation system to determine whether damage has occurred inside the structure.

[0004] Ultrasonic testing requires many measuring points, and the workload will be greatly increased when the measurement progress is required. For composite components with external steel plates, the shielding effect of external steel plates on ultrasonic waves needs further study. Piezoelectric ceramic stress wave detection can only determine whether a defect exists by comparing the signal amplitude with the healthy measuring point, but cannot determine the depth of the defect.

[0005] In summary, existing detection methods are mostly used for damage detection of ordinary reinforced concrete components, and can only qualitatively determine whether defects exist, but cannot determine the specific size and location of the defects. Summary of the invention

[0006] In view of this, the present invention proposes a method for testing the void defects of steel box concrete shear walls, aiming to solve the above-mentioned technical problems existing in the prior art.

[0007] The present invention proposes a method for testing the hollowing defects of a steel box concrete shear wall, comprising the following steps:

[0008] Step 1: Use ultrasonic method to measure the steel box concrete shear wall component over a large area to determine the suspected area of ​​the void defect, and mark the suspected area of ​​the void defect;

[0009] Step 2, laying a plurality of piezoelectric sensors on the outer surface of the steel box concrete shear wall component to accurately detect the area of ​​the suspected void defect region;

[0010] Step 3: Use a temperature detection method to detect the void depth of the suspected void defect area.

[0011] Furthermore, in the above-mentioned steel box concrete shear wall void defect testing method, in the step 1, a plurality of ultrasonic transmitting probes and a plurality of ultrasonic receiving probes are respectively arranged on opposite sides of the steel box concrete shear wall component.

[0012] Furthermore, in the above-mentioned steel box concrete shear wall void defect testing method, in step 2, the signals received by the piezoelectric sensors arranged on the same side and the opposite side of the same facade are collected by the data acquisition system, and the void area is characterized by a "line".

[0013] Furthermore, in the above-mentioned steel box concrete shear wall void defect testing method, in the step 3, the void defect area of ​​the steel box concrete shear wall component is subjected to infrared thermal imaging scanning to characterize the void defect area by means of a temperature field.

[0014] The steel box concrete shear wall void defect testing method of the present invention provides technical support for quantitative detection of steel box concrete shear walls through ultrasonic method, piezoelectric sensor and infrared temperature testing method, and provides a safety assessment means for the use of steel box concrete shear wall components. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0016] Figure 1 A schematic diagram of a flow chart of a method for testing a hollow defect of a steel box concrete shear wall provided by an embodiment of the present invention;

[0017] Figure 2 It is a schematic diagram of ultrasonic testing method for steel box concrete shear wall in an embodiment of the present invention;

[0018] Figure 3 Schematic diagram of piezoelectric ceramic detection on the outside of a steel box concrete shear wall in an embodiment of the present invention;

[0019] Figure 4 Schematic diagram of temperature detection of steel box concrete shear wall in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] See also Figure 1 The method for testing the hollowing defect of the steel box concrete shear wall according to the embodiment of the present invention comprises the following steps:

[0022] Step S1, using an ultrasonic method to perform a large-area measurement on the steel box concrete shear wall component, determine the suspected area of ​​the void defect, and mark the suspected area of ​​the void defect.

[0023] Specifically, multiple ultrasonic transmitting probes and multiple ultrasonic receiving probes are respectively set on the opposite sides of the steel box concrete shear wall components. The first wave sound time theory can be used to identify the abnormal sound velocity area (under dense conditions, the sound time difference of each measuring point is very small. If it exceeds ±5% of the average sound time value of the measuring area, it is an abnormal point), mark it as a defective area and wait for the next step of detection. The void area is characterized by the "point set" method. More specifically, each pair of transmitting probes and receiving probes can be numbered, see Figure 2 The abnormal point of sound time is the area numbered ④.

[0024] Step S2, laying a plurality of piezoelectric sensors on the outer surface of the steel box concrete shear wall component to accurately detect the area of ​​the suspected void defect region.

[0025] Specifically, since the ultrasonic method uses points to represent abnormal areas, the specific size of the defect cannot be determined. The piezoelectric ceramic method can be used to determine whether the area between the two measuring points has defects. In this embodiment, the external piezoelectric ceramic stress wave flaw detection technology is used to accurately detect the suspected defect area. The data acquisition system collects the signals received by the piezoelectric sensors arranged on the same side and the opposite side of the same facade, and the empty area is characterized by a "line". For example, the amplitude of the signal received by the receiving end sensor can be used to characterize the width of the defect.

[0026] When there is an interface detachment defect on the steel plate surface, the stress wave component propagating along the steel plate surface increases, while the component propagating into the concrete decreases. Moreover, when the size of the interface debonding defect continues to increase, the stress wave component propagating along the steel plate surface further increases, while the component propagating into the concrete gradually decreases.

[0027] See also Figure 3 , gradually indenting the loose area into the real area. Since defects are easily generated at the interface between the loose area and the dense area, in this embodiment, defects at different positions are tested in the following direction: straight line AA→straight line BB→straight line CC. The lengths of straight lines AA, BB, and CC are different, which can be used to characterize the width of the defect.

[0028] Step S3, using a temperature detection method to detect the void depth of the void defect suspected area.

[0029] Specifically, the hollow defect area of ​​the steel box concrete shear wall component is scanned by infrared thermal imaging to characterize the hollow defect area through the temperature field.

[0030] See also Figure 4 ,Since different hollowing depths will produce different temperature differences on the surface of the steel pipe, the hollowing area is characterized by a two-dimensional “temperature field”.

[0031] When there is a hollow defect in steel tube concrete, the space between the inner wall of the steel tube and the core concrete is filled with air, and the thermal conductivity of steel is much greater than that of air. In the dense part, the steel can directly transfer the absorbed heat to the core concrete; in the hollow part, the heat needs to pass through the air before reaching the concrete, and the heat transfer is slow. In practice, the temperature of the steel tube in the stripped part is higher than that in the dense part.

[0032] from Figure 4 It can be seen that the temperature of the measuring point corresponding to the defect area is abnormal. The higher the temperature, the greater the depth of the defect.

[0033] The method for testing the void defects of steel box concrete shear walls provided by the present invention determines a large range of void defects by ultrasonic measurement, further determines the void area by a piezoelectric sensor, and finally tests the void depth by infrared temperature. This provides technical support for quantitative detection of steel box concrete shear walls and provides a safety assessment method for the use of steel box concrete shear wall components.

[0034] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for testing the hollowing defects of steel box concrete shear walls, characterized in that: The following steps are involved: Step 1: multiple ultrasonic transmitting probes and multiple ultrasonic receiving probes are respectively set on opposite sides of the steel box concrete shear wall component, and the first wave acoustic time theory is used to identify the abnormal sound velocity area and mark it as a suspected defect area; Step 2: a plurality of piezoelectric sensors are laid on the outer surface of the steel box concrete shear wall component to accurately detect the area of ​​the suspected void defect region, and the signals received by the piezoelectric sensors arranged on the same side and the opposite side of the same facade are collected by the data acquisition system, and three detection points A, B, and C are arranged in sequence on the same side of the same facade, and three detection points C, B, and A are arranged in sequence on the opposite side of the same facade, and the void area is characterized by a "line" method, and defects at different positions are tested in the direction of straight line AA→straight line BB→straight line CC, gradually shrinking from the uncompacted area to the real area; the width of the defect is characterized by the length of straight line AA, straight line BB, and straight line CC; Step 3: Scan the hollow defect area of ​​the steel box concrete shear wall component with infrared thermal imaging to characterize the hollow defect area through temperature field. The temperature of the measuring point corresponding to the defect area is abnormal. The higher the temperature, the greater the depth of the defect.

2. The method for testing the hollowing defect of steel box concrete shear wall according to claim 1 is characterized in that: In the step 1, a plurality of ultrasonic transmitting probes and a plurality of ultrasonic receiving probes are respectively arranged on opposite sides of the steel box concrete shear wall component.

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