An integrated ultrasonic probe's cable anchor down pressure testing device

Abstract

The utility model relates to an anchor cable anchor under pressure testing arrangement of integrated ultrasonic probe, it includes anchor backing plate, the disc -shaped work anchor plate of anchor backing plate top is provided with, sets up the grommet between anchor backing plate and work anchor plate, the grommet includes inner ring and outer ring, the outer peripheral surface of inner ring is the outer conical surface, the inner peripheral surface of outer ring is the inner conical surface, the conical surface curvature radius of outer conical surface is consistent with the conical surface curvature radius of inner conical surface, sets up two magnetic attraction piece on the outer peripheral surface of outer ring, two magnetic attraction piece are respectively integrated and installed with ultrasonic probe, and ultrasonic probe is connected with ultrasonic probe wire. The utility model can realize the real -time monitoring to the bridge prestress change, need not to remove the sealed anchor structure to complete bridge prestress nondestructive testing.

Description

Technical Field

[0001] This utility model belongs to the field of bridge anchorage prestress detection technology, specifically an anchorage pressure testing device integrating an ultrasonic probe. Background Technology

[0002] As a crucial component of infrastructure construction, bridges play a vital role in connecting transportation networks. As a widely used bridge type, prestressed concrete bridges hold an important position in bridge engineering due to their superior structural performance and economic benefits, playing a particularly crucial role in highways, urban rail transit, and other important transportation infrastructure projects. These bridges can span long distances, withstand heavy loads, and possess good durability and low maintenance costs.

[0003] As prestressed concrete bridges age, their load-bearing capacity decreases. In practical engineering, the long-term performance degradation and deterioration of prestressing tendons shorten the service life of concrete bridges. The effective prestress under the bridge anchorage is the most direct and important indicator of whether the prestressing system is functioning properly. It is also a crucial basis for evaluating the stress state of the bridge structure and for developing maintenance and reinforcement plans for bridges in service.

[0004] Testing the prestress under anchorage during the construction period is relatively easy. In actual projects, methods such as the hydraulic jack and gauge replacement method, the anchorage pressure ring method, the strain method, or the impedance method are commonly used. However, testing after construction is more difficult. For non-embedded prestressed strands, X-ray diffraction, stress release methods, and micro-pore stress release methods for reinforcing bars are typically used. These methods all cause damage to the original structure during the testing process. Non-destructive testing methods mainly include fiber optic grating testing, acoustic emission technology, and vibration-based testing methods. Fiber optic grating testing offers high accuracy and a clear principle, but it is sensitive to both strain and temperature. Acoustic emission technology is simple to operate and has good dynamic response, but the signal is easily interfered with. Vibration-based testing methods have high recognition accuracy and are easy to measure, but the error is relatively large. Therefore, establishing an economical, universal, and effective method for identifying the prestress under anchorage in post-tensioned anchorage systems with loose or insufficiently tensioned steel strands is of great significance for prestressed concrete beam bridges. Utility Model Content

[0005] To achieve the above objectives, this utility model provides the following technical solution: an anchor cable anchor pressure testing device integrating an ultrasonic probe, used for bridge anchor prestress detection, including an anchor plate, with a disc-shaped working anchor plate disposed above the anchor plate. The anchor plate and working anchor plate are installed in the bridge during bridge construction. The steel strand is the anchor cable. During bridge construction, a spacer is first placed between the anchor plate and the working anchor plate, and then prestress is applied to the steel strand to make it taut. The spacer includes an inner ring and an outer ring. The outer circumferential surface of the inner ring is an outer conical surface, and the inner circumferential surface of the outer ring is an inner conical surface. The radius of curvature of the outer conical surface is the same as that of the inner conical surface. The outer conical surface is in contact with the inner conical surface. The working anchor plate is located above the pad ring. The pad ring is set on the anchor plate. The lower end of the prestressed steel strand passes through the pad ring and the anchor plate and protrudes outside the anchor plate. The upper end of the prestressed steel strand protrudes outside the working anchor plate. Two magnetic blocks are provided on the outer circumference of the outer ring. The two magnetic blocks are symmetrically arranged around the central axis of the outer ring. An ultrasonic probe is integrated and installed on each of the two magnetic blocks. The ultrasonic probe is connected to an ultrasonic probe wire.

[0006] Preferably, a signal processing device is installed outside the bridge, and the ultrasonic probe wire is connected to the signal processing device outside the bridge.

[0007] Preferably, the anchor plate is pre-embedded in the bridge during bridge construction, the prestressed steel strand is prestressed and tensioned during bridge construction, and the working anchor plate presses on the inner ring.

[0008] Preferably, the lower outer diameter of the working anchor plate matches the upper outer diameter of the inner ring, and the lower end of the working anchor plate is located inside the upper hole of the inner ring.

[0009] Preferably, there are two inner rings, which are stacked one on top of the other.

[0010] Preferably, both the outer ring and the inner ring are made of spring steel.

[0011] Preferably, the working anchor plate is provided with a working clamp, which clamps the prestressed steel strand to fix the prestressed steel strand together with the working anchor plate.

[0012] Preferably, under the action of external force, the outer ring and the inner ring are compressed, and the relationship between the change in the contact area between the outer ring and the inner ring and the change in the prestress under the bridge anchor is as follows:

[0013]

[0014] In the above formula, ∆F represents the change in prestress; E represents the elastic modulus; ∆A represents the change in the contact area between the inner and outer rings; D 01 D is the diameter of the center of the outer ring cross-section.01 =D1-b1-h·tanβ / 4;D 02 D is the diameter of the center of the outer ring cross-section. 02 =D2+b2+h·tanβ / 4 is; A1 is the cross-sectional area of ​​the outer ring, A1=hb1+h 2 ·tanβ / 4; A2 is the cross-sectional area of ​​the inner ring, A1=hb2+h 2 ·tanβ / 4; β is the cone angle, taken as β=14°3′; ρ is the friction angle between the inner and outer rings, ρ=8°30′; D1 is the outer diameter of the outer ring, D2 is the inner diameter of the inner ring, b1 is the thickness of the outer ring, b2 is the thickness of the inner ring, and h is the height of the washer ring.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] This utility model device has a simple structure and low cost. During the prestressed construction stage, the pad ring is installed between the working anchor plate and the anchor plate, and the ultrasonic signal is led out to the outside of the bridge through the wire to realize real-time monitoring of the changes in the prestress of the bridge. This detection method can complete the non-destructive testing of the prestress of the bridge without removing the sealing anchor structure.

[0017] This device can effectively monitor the health status of bridges by monitoring their prestress in real time, detect abnormalities in advance, and carry out repairs and reinforcements to ensure the safety and quality of the bridge structure, thereby improving the safety and service life of the bridge. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the pad ring and the two magnetic blocks in this utility model;

[0019] Figure 2 This is a schematic diagram of the structure of the gasket ring in this utility model;

[0020] Figure 3 This is an exploded view of the structure of this utility model;

[0021] Figure 4 This is a schematic diagram of the assembled structure of the anchor cable anchor pressure testing device with integrated ultrasonic probe of this utility model. Detailed Implementation

[0022] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0024] This invention proposes an anchor cable anchor pressure testing device with an integrated ultrasonic probe. Please refer to [reference needed]. Figure 1 ,to Figure 4 The system includes an anchor plate 1, with a disc-shaped working anchor plate 2 positioned above the anchor plate 1. Prestressed steel strands 3 pass through the working anchor plate 2. A washer 4 is positioned between the anchor plate 1 and the working anchor plate 2. The washer 4 includes an inner ring 5 and an outer ring 6. The outer circumferential surface of the inner ring 5 is an outer conical surface, and the inner circumferential surface of the outer ring 6 is an inner conical surface. The radius of curvature of the outer conical surface is the same as that of the inner conical surface. The outer conical surface contacts the inner conical surface. Anchor plate 2 is located above washer 4, which is mounted on anchor plate 1. One end of prestressed steel strand 3 passes through washer 4 and anchor plate 1, protruding outside anchor plate 1, while the other end protrudes outside working anchor plate 2. Two magnetic blocks 7 are provided on the outer circumference of outer ring 6, symmetrically arranged around the central axis of outer ring 6. Ultrasonic probes 8 are integrated and mounted on the two magnetic blocks 7, and ultrasonic probe wires 9 are connected to the ultrasonic probes 8. The end face of magnetic block 7 that contacts outer ring 6 is an arc-shaped surface, with the arc surface having the same radius of curvature as outer ring 6, which facilitates close contact between magnetic block 7 and washer 4.

[0025] Signal processing equipment (not shown in the figure) is installed outside the bridge, and the ultrasonic probe wire 9 is connected to the signal processing equipment outside the bridge. The ultrasonic probe 8 on one magnetic block 7 is the signal transmitting end, and the ultrasonic probe 8 on another magnetic block 7 is the signal receiving end, and they are respectively connected to the signal processing equipment outside the prestressed bridge through the ultrasonic probe wire 9.

[0026] Preferably, the anchor plate 1 is pre-embedded in the bridge during bridge construction, the prestressed steel strand 3 is prestressed and tensioned during bridge construction, and the working anchor plate 2 is pressed on the inner ring 5.

[0027] Preferably, the lower outer diameter of the working anchor plate 2 matches the upper outer diameter of the inner ring 5, and the lower end of the working anchor plate 2 is located inside the upper hole of the inner ring 5.

[0028] Preferably, there are two inner rings 5, which are stacked one on top of the other.

[0029] Preferably, both the outer ring 6 and the inner ring 5 are made of spring steel.

[0030] Preferably, the working anchor plate 2 is provided with a working clamp 10, which clamps the prestressed steel strand 3 to fix the prestressed steel strand 3 together with the working anchor plate 2.

[0031] In actual use, the integrated ultrasonic probe of this utility model, the anchor cable anchor pressure testing device and the prestressed steel strand 3 are both placed horizontally, and the prestressed steel strand 3 should be in a taut state under the action of prestress.

[0032] Based on the theory of wave propagation and energy dissipation at the interface, it is known that the contact area of ​​the contact medium will increase under pressure. During the propagation of the ultrasonic signal within the medium, the transmitted wave will increase, the reflected wave will decrease, and the signal energy loss will increase. The contact area between the outer ring 6 and the inner ring 5 of the test pad is positively correlated with the applied external force load.

[0033] After the prestressed steel strand 3 is prestressed during construction, a sweep frequency signal is emitted through one transmitting ultrasonic probe 8, and the signal is received by another receiving ultrasonic probe 8. The signal transmission energy is then analyzed using signal processing equipment. During subsequent monitoring of the prestressed bridge, the signal transmission energy obtained each time is compared with the signal transmission energy immediately after construction. If the signal energy decreases, it indicates that the prestress on the bridge is decreasing.

[0034] After a long period of use, the tension of the prestressed steel strand 3 decreases, the prestressed steel strand 3 becomes loose or insufficiently tensioned, and the contact area between the outer ring 6 and the inner ring 5 of the pad ring decreases, indicating that the prestress of the prestressed steel strand 3 decreases and the prestress on the bridge is reduced. When the prestress on the bridge decreases to a certain extent, it needs to be reinforced or repaired.

[0035] Based on the ultrasonic reflection theory of interface contact, the relationship between tension force and signal transmission loss can be accurately quantified, and the prestress of bridges under non-destructive conditions after construction can be effectively tested. This reduces the difficulty of prestress testing under anchors, effectively solves the health monitoring problem of prestressed concrete beam bridges, and improves bridge safety and monitoring economy.

[0036] Preferably, under the action of external force, the outer ring and the inner ring are compressed, and the relationship between the change in the contact area between the outer ring and the inner ring and the change in the prestress under the bridge anchor is as follows:

[0037]

[0038] In the above formula, ∆F represents the change in prestress; E represents the elastic modulus; ∆A represents the change in the contact area between the inner and outer rings; D 01 D is the diameter of the center of the outer ring cross-section. 01 =D1-b1-h·tanβ / 4;D 02D is the diameter of the center of the outer ring cross-section. 02 =D2+b2+h·tanβ / 4 is; A1 is the cross-sectional area of ​​the outer ring, A1=hb1+h 2 ·tanβ / 4; A2 is the cross-sectional area of ​​the inner ring, A1=hb2+h 2 ·tanβ / 4; β is the cone angle, taken as β=14°3′; ρ is the friction angle between the inner and outer rings, ρ=8°30′; D1 is the outer diameter of the outer ring, D2 is the inner diameter of the inner ring, b1 is the thickness of the outer ring, b2 is the thickness of the inner ring, and h is the height of the pad ring. Based on this formula, the bridge external signal processing equipment can obtain the absorption signal of the change in the contact area between the outer ring 6 and the inner ring 5 through the ultrasonic probe 8, and calculate the change value of the prestress under the bridge anchor, thereby realizing real-time monitoring of the bridge prestress change. This detection method can complete the non-destructive testing of the bridge prestress without removing the anchor sealing structure. This utility model device, through real-time monitoring of the bridge prestress, can effectively grasp the health status of the bridge, detect abnormalities in advance, and implement maintenance and reinforcement, ensuring the safety and quality of the bridge structure, thereby improving the bridge's service safety and service life.

[0039] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An anchor cable under-anchor pressure testing device with integrated ultrasonic probe, used for detecting prestress under bridge anchors, comprising an anchor plate, wherein a disc-shaped working anchor plate is disposed above the anchor plate, characterized in that: A gasket is provided between the anchor plate and the working anchor plate. The gasket includes an inner ring and an outer ring. The outer circumferential surface of the inner ring is an outer conical surface, and the inner circumferential surface of the outer ring is an inner conical surface. The radius of curvature of the outer conical surface is the same as that of the inner conical surface. The outer conical surface is in contact with the inner conical surface. The working anchor plate is located above the gasket. The gasket is set on the anchor plate. The upper end of the prestressed steel strand protrudes outside the working anchor plate. Two magnetic blocks are provided on the outer circumferential surface of the outer ring. The two magnetic blocks are symmetrically arranged around the central axis of the outer ring. An ultrasonic probe is integrated and installed on each of the two magnetic blocks. The ultrasonic probe is connected to an ultrasonic probe wire.

2. The anchor cable anchor pressure testing device with integrated ultrasonic probe according to claim 1, characterized in that: Signal processing equipment is installed outside the bridge, and the ultrasonic probe wire is connected to the signal processing equipment outside the bridge.

3. The anchor cable anchor pressure testing device with integrated ultrasonic probe according to claim 2, characterized in that: The lower outer diameter of the working anchor plate matches the upper outer diameter of the inner ring, and the lower end of the working anchor plate is located inside the upper hole of the inner ring.

4. The anchor cable anchor pressure testing device with integrated ultrasonic probe according to claim 3, characterized in that: There are two inner rings, which are stacked one on top of the other.

5. The anchor cable anchor pressure testing device with integrated ultrasonic probe according to claim 4, characterized in that: Both the outer and inner rings are made of spring steel.

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