Water tightness test structure and method for carbon fiber inhaul cable anchorage device

Abstract

The invention discloses a carbon fiber inhaul cable anchorage device water tightness test structure and method, the structure comprises a pre-buried pipe, a sealing assembly, a pressing device, a hollow pipe and an end cover, one end of the pre-buried pipe is connected with the pressing device, the other end of the pre-buried pipe is connected with the end cover, the sealing assembly is arranged in an inner cavity of the pre-buried pipe, and the hollow pipe penetrates through the sealing assembly and then is connected with the end cover. According to the invention, by arranging the two bottom bolts to extrude the deformable sealing assembly, radial sealing of the sealing assembly on the hollow pipe is further realized, the technical effect of testing the sealing performance of the hollow pipe and the anchoring assembly is realized, and meanwhile, the technical problem of anchorage device sealing of the carbon fiber composite stranded wire with the steel sheath is also solved. After the end cover is removed, the bridge anchoring device can be directly used for bridge anchoring installation and use, it is ensured that whether the sealing performance is qualified or not can be fully checked before use, and the later maintenance cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of bridge anchorage technology, and particularly relates to the test structure and method for water tightness of carbon fiber cable anchorages. Background Technology

[0002] The prestressing tension element used in carbon fiber cables is carbon fiber composite strand. Carbon fiber composite strand has advantages such as lightweight, high strength, excellent corrosion resistance, and fatigue resistance. It can replace steel strand as the prestressing tension element and does not require a separate extruded HDPE sheath. It can effectively solve the problem of reduced structural life caused by easy corrosion of steel. At the same time, it can reduce the self-weight of the prestressed structure and increase the span of the bridge. However, the existing supporting metal anchoring unit still has problems such as effective prestress loss and even anchoring failure caused by easy corrosion.

[0003] Because carbon fiber composite strands have high tensile strength but low shear strength, their shear resistance is weak, making direct anchoring with clamps or anchor plates unsuitable. A steel sheath must be pre-pressed onto the carbon fiber composite strand to form a unified structure, increasing shear strength for radial clamping by the clamps. Allowing the carbon fiber composite strand with the steel sheath to pass through the sealing assembly inevitably increases the gap between the sealing assembly and the strand, making radial deformation sealing difficult, or causing the sealing assembly to thicken axially, resulting in an unlimited increase in the overall structure. Therefore, a structure is needed to reduce the gap between the sealing assembly and the carbon fiber composite strand. However, the sealing effect of such a structure is unknown, requiring further verification of the sealing system's effectiveness, thus necessitating corresponding sealing performance testing methods.

[0004] Patent application No. 2022114623021 discloses an anchorage and its tensioning method based on uniformly applying cable force to a stay cable. This anchorage involves passing a steel strand through an anchoring plate, connecting it to a support cylinder via an annular inclined plane, and then using anchoring bolts to connect the anchoring plate and the support cylinder. The steel strand, equipped with a sensor, is then initially tensioned and anchored using clamps. While the document discloses adding a sheath to the strand to improve its lifespan, this structure cannot perform watertightness testing before installation. Furthermore, the sensor in this structure is used to assess the tensioning accuracy of the steel strand and does not involve temperature and humidity monitoring.

[0005] Patent application No. 2019102861756 discloses a water tightness testing device with a static locking device, which can be applied to cable water tightness testing. After the hollow jack outputs force to a predetermined value, the device can assist in unloading the hollow jack, causing the hollow jack to withdraw from work, thereby reducing the output of the hollow jack's hydraulic system and enabling the cable to maintain its original test tension.

[0006] Patent application No. 202323212565X discloses a static water tightness testing machine for epoxy-coated steel strands, which is equipped with a water tank and a sealed testing chamber to perform static water tightness testing on epoxy-coated steel strands.

[0007] The two types of equipment mentioned above can only be used for water tightness testing, and the equipment cannot be installed and used on the construction site after the test. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a test structure and method for the water tightness of carbon fiber cable anchors.

[0009] The present invention is achieved through the following technical solutions.

[0010] The carbon fiber cable anchor water tightness test structure provided by the present invention includes a pre-embedded pipe, a sealing component, a clamping device, a hollow pipe and an end cap. One end of the pre-embedded pipe is connected to the clamping device and the other end is connected to the end cap. The sealing component is disposed in the inner cavity of the pre-embedded pipe. The hollow pipe passes through the sealing component and is connected to the end cap.

[0011] Preferably, the sealing assembly is provided with a first through hole and a first bolt, the hollow tube passes through the sealing assembly through the first through hole, the first bolt is threadedly connected to the sealing assembly, a temperature and humidity sensor is provided inside the hollow tube, and the outer end of the hollow tube is sealed by a flexible sealing method.

[0012] Preferably, the sealing assembly is provided with a positioning hole and a pressure rod, one end of the pressure rod extends into the positioning hole and is connected, and the other end is connected to the inner wall of the end cap.

[0013] Preferably, the sealing assembly includes an outer sealing plate, a middle sealing plate, a damage prevention plate, and an inner sealing plate, which are arranged sequentially from right to left inside the pre-embedded pipe.

[0014] Preferably, the middle sealing plate, the damage prevention plate, and the inner sealing plate are each provided with a second through hole on the same axis, and the outer sealing plate is provided with a screw hole.

[0015] Preferably, the outer sealing plate and the damage prevention plate are made of plastic, and the middle sealing plate is made of polyurethane foam.

[0016] Preferably, a first countersunk hole is provided in the pre-embedded pipe to limit the installation of the sealing component. One end of the pre-embedded pipe is provided with an external thread and the other end is provided with an internal thread. The pre-embedded pipe is threaded to the end cap through the external thread and threaded to the clamping device through the internal thread.

[0017] Preferably, the end cap is coaxially provided with a threaded through hole, a limiting countersunk hole and a blind hole, the end cap is provided with a second bolt, the end cap is threadedly connected to the second bolt through the threaded through hole, the end cap is connected to the pressure rod through the limiting countersunk hole, and the end cap is connected to the hollow tube through the blind hole.

[0018] The installation method of the watertightness test structure for carbon fiber cable anchors includes the following steps: S1. Use the first bolt to sequentially tighten and connect the inner sealing plate, the damage prevention plate, the middle sealing plate, and the outer sealing plate to form a sealing assembly. S2. Tightly screw the external threaded end of the embedded pipe to the internal thread of the end cap. Apply sealant to the threads before installation to ensure a tight seal at the threaded connection. S3. Position and install the pressure rod within the limiting countersunk hole of the end cap. S4. Pass the hollow tube through the first through hole into the sealing assembly, and position it in a hole-axis fit with the blind hole of the end cap. Install the sealing assembly along the axis of the embedded tube into the first countersunk hole of the embedded tube, while ensuring that the pressure rod and the sealing assembly are positioned in a hole-axis fit. S5. Install the clamping device, and before installation, apply sealant to both the external thread of the clamping device and the internal thread of the embedded pipe to ensure a tight and sealed connection at the threaded joint. S6. Install the second bolt, and tighten the second bolt in stages with the same torque wrench. The preload of the second bolt is transmitted to the sealing assembly through the pressure bar to ensure that the sealing assembly and all hollow tubes are sealed.

[0019] The test method for the water tightness test structure of carbon fiber cable anchors includes the following steps: S7. Place the temperature and humidity sensor inside the hollow tube and seal the exposed port of the hollow tube with flexible sealant. S8. Connect the interface of the temperature and humidity sensor to the data acquisition unit, monitor the humidity data, and then immerse the water tightness test device with the temperature and humidity sensor installed in water for 3 days. S9. If the daily humidity change does not exceed 1% during the testing period, and the relative humidity change within 3 days does not exceed 3%, then the sealing effect of the sealing device is deemed qualified; otherwise, it is deemed unqualified.

[0020] The beneficial effects of this invention are as follows: This invention reduces the gap between the sealing component and the carbon fiber composite strand by using a hollow tube. The sealing component, which can be deformed by the compression of two bottom bolts, achieves radial sealing of the hollow tube. This invention can be used to test the sealing performance of the hollow tube and the anchoring component, simplifying the testing equipment. It also solves the sealing problem of anchorages with steel sheaths on carbon fiber composite strands, preventing water and other liquids from entering the anchoring unit and steel sheath through the gap between the tensioning element and the sealing component, thus improving the structure's corrosion resistance and extending its lifespan. This invention can test the watertightness of the hollow tube after installation, and after removing the end caps, the structure can be directly used for bridge anchoring, ensuring that its sealing performance can be fully tested before use, reducing subsequent maintenance costs. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the sealing assembly of Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the structure of the pressure bar of the present invention; Figure 4 This is a schematic diagram of the sealing assembly in Embodiment 2 of the present invention; Figure 5 This is a schematic diagram of the structure of Embodiment 3 of the present invention; In the diagram: 1-Embedded pipe, 11-First countersunk hole, 2-Sealing assembly, 21-Outer sealing plate, 22-Middle sealing plate, 23-Damage protection plate, 24-Inner sealing plate, 25-First through hole, 26-Second through hole, 27-Threaded hole, 28-Positioning hole, 3-Clamping device, 4-Hollow tube, 5-End cap, 51-Threaded through hole, 52-Limiting countersunk hole, 53-Blind hole, 6-First bolt, 7-Pressure rod, 8-Second bolt, 9-Temperature and humidity sensor, 10-Carbon fiber composite stranded wire, 101-Force transmission component, 102-Anchoring assembly, 103-Protective cover. Detailed Implementation

[0022] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0023] Example 1: like Figures 1 to 3 As shown, the water tightness test structure of the carbon fiber cable anchor includes a pre-embedded pipe 1, a sealing component 2, a clamping device 3, a hollow pipe 4, and an end cap 5. One end of the pre-embedded pipe 4 is connected to the clamping device 3, and the other end is connected to the end cap 5. The sealing component 2 is set in the inner cavity of the pre-embedded pipe 1, and the hollow pipe 4 passes through the sealing component 2 and is connected to the end cap 5.

[0024] The sealing component 2 is provided with a first through hole 25 and a first bolt 6. The hollow tube 4 passes through the sealing component 2 through the first through hole 25. The first bolt 6 is threadedly connected to the sealing component 2. A temperature and humidity sensor 9 is provided inside the hollow tube 4 near the end cap 5 to monitor the changes in temperature and humidity inside the hollow tube 4, thereby determining the water tightness inside the hollow tube 4. The outer end of the hollow tube 4 is sealed with silicone sealant, which is a flexible sealing method that seals the outer end of the hollow tube opening to ≥5mm inward.

[0025] The sealing assembly 2 is provided with positioning holes 28 and pressure rods 7. One end of the pressure rod 7 extends into the positioning hole 28 and connects to the sealing assembly 2 to achieve hole-shaft positioning. The other end connects to the inner wall of the end cover 5. Positioning holes 28 are coaxially provided on the middle sealing plate 22 and the anti-damage plate 23. The number of positioning holes 28 is ≥2, and the number of pressure rods 7 corresponds to the number of positioning holes 28. The pressure rods 7 are as follows: Figure 3 As shown, the left end that transmits force to the second bolt 8 is larger in size, which facilitates force transmission, while the right end that positions the sealing component 2 is smaller in size, which facilitates insertion into the positioning hole 28.

[0026] The sealing assembly 2 includes an outer sealing plate 21, a middle sealing plate 22, a damage prevention plate 23, and an inner sealing plate 24, which are arranged sequentially from right to left inside the pre-embedded pipe 1.

[0027] The middle sealing plate 22, the damage prevention plate 23 and the inner sealing plate 24 are respectively provided with second through holes 26 on the same axis, and the outer sealing plate 21 is provided with screw holes 27. The first bolt 6 passes through the second through holes 26 on the middle sealing plate 22, the damage prevention plate 23 and the inner sealing plate 24 in sequence and is threadedly connected to the screw hole 27 on the outer sealing plate 21.

[0028] The outer sealing plate 21 and the anti-damage plate 23 are made of plastic, which can transmit pressure and convert axial compression deformation into radial gain deformation. The middle sealing plate 22 is made of polyurethane foam, which can convert axial compression deformation into radial gain deformation, thereby realizing the radial sealing function of the sealing component 2.

[0029] The pre-embedded pipe 1 is provided with a first countersunk hole 11, which limits the installation of the sealing component 2. One end of the pre-embedded pipe 1 is provided with an external thread, and the other end is provided with an internal thread. The pre-embedded pipe 1 is threaded to the end cap 5 through the external thread and to the clamping device 3 through the internal thread.

[0030] The end cap 5 is coaxially provided with a threaded through hole 51, a limiting countersunk hole 52, and a blind hole 53. A second bolt 8 is provided on the end cap 5. The end cap 5 is threadedly connected to the second bolt 8 through the threaded through hole 51. The end cap 5 is connected to the pressure rod 7 through the limiting countersunk hole 52. The end cap 5 is connected to the hollow tube 4 through the blind holes 53. The number of blind holes 53 is consistent with the number of hollow tubes 4, used for positioning and installation of the hollow tube 4. When installing the second bolt 8, tighten the second bolt 8 until it touches the pressure rod 7, and continue to press the pressure rod 7 until the pressure rod 7 transmits pressure to the sealing assembly 2, and the axial compression of the sealing assembly 2 is converted into a radial seal on the hollow tube 4.

[0031] Steps for testing the water tightness of carbon fiber cable anchors: S1. Use the first bolt 6 to sequentially fasten the inner sealing plate 24, the damage prevention plate 23, the middle sealing plate 22, and the outer sealing plate 21 to form the sealing assembly 2. S2. Tighten the external thread end of the pre-embedded pipe 1 to the internal thread of the end cap 5, and apply sealant to the threads before installation to ensure a seal at the threaded connection. S3. Position and install the pressure rod 7 within the limiting countersunk hole 52 of the end cap 5. S4. Pass the hollow tube 4 through the first through hole 25 into the sealing assembly 2, and position it in a hole-axis fit with the blind hole 53 of the end cap 5. Install the sealing assembly 2 along the axis of the embedded tube 1 into the first countersunk hole 11 of the embedded tube 1, while ensuring that the pressure rod 7 and the sealing assembly 2 are positioned in a hole-axis fit. S5. Install the clamping device 3, and before installation, apply sealant to both the external thread of the clamping device 3 and the internal thread of the embedded pipe 1 to ensure a tight seal at the threaded connection. S6. Install the second bolt 8, and tighten the second bolt 8 in stages with the same torque wrench. The preload of the second bolt 8 is transmitted to the sealing assembly 2 through the pressure rod 7 to ensure that the sealing assembly 2 and all hollow tubes 4 are sealed.

[0032] The test method and steps for the water tightness test structure of carbon fiber cable anchors are as follows: S7. Place the temperature and humidity sensor 9 inside the hollow tube 4 near the end cap 5, and seal the exposed port of the hollow tube 4 with silicone sealant. S8. Connect the interface of the temperature and humidity sensor 9 to the data acquisition unit to monitor the humidity data, and then immerse the water tightness test device with the temperature and humidity sensor 9 installed in water for 3 days. S9. If the daily humidity change does not exceed 1% during the testing period, and the relative humidity change within 3 days does not exceed 3%, then the sealing effect of the sealing device is deemed qualified; otherwise, it is deemed unqualified.

[0033] Example 2: like Figure 4 As shown, the water tightness test structure of the carbon fiber cable anchor is basically the same as that of Example 1, except that the middle sealing plate 22 is positioned differently. The sealing assembly 2 includes an outer sealing plate 21, a middle sealing plate 22, a damage prevention plate 23, and an inner sealing plate 24. These components are arranged sequentially from right to left within the pre-embedded pipe 1 to enhance the sealing effect on the hollow pipe 4.

[0034] Example 3: like Figure 5 As shown, the qualified carbon fiber cable anchor water tightness test structure can be directly used for bridge anchorage construction. A carbon fiber composite strand 10 is installed inside the hollow tube 4 as a prestressed tension element for the carbon fiber cable. The carbon fiber cable anchor water tightness test structure is basically the same as in Example 1, except that one end of the embedded pipe 1 is not connected to the end cap 5, but instead connected to the anchoring assembly 102 via a force transmission component 101. The other end of the anchoring assembly 102 is connected to a protective cover 103. The hollow tube 4 penetrates the anchoring assembly 102 and extends into the inner cavity of the protective cover 103 to achieve end protection. The second bolt 8 penetrates the anchoring assembly 102 and is threadedly connected before pressing down on the pressure rod 7. One end of the pressure rod 7 extends to connect with the corresponding blind hole in the anchoring assembly 102.

Claims

1. A test structure for the water tightness of carbon fiber cable anchors, characterized in that: It includes a pre-embedded pipe (1), a sealing assembly (2), a clamping device (3), a hollow pipe (4) and an end cap (5). One end of the pre-embedded pipe (4) is connected to the clamping device (3) and the other end is connected to the end cap (5). The sealing assembly (2) is set in the inner cavity of the pre-embedded pipe (1). The hollow pipe (4) passes through the sealing assembly (2) and is connected to the end cap (5).

2. The watertightness test structure for carbon fiber cable anchors as described in claim 1, characterized in that: The sealing assembly (2) is provided with a first through hole (25) and a first bolt (6). The hollow tube (4) passes through the sealing assembly (2) through the first through hole (25). The first bolt (6) is threadedly connected to the sealing assembly (2). A temperature and humidity sensor (9) is provided inside the hollow tube (4). The outer end of the hollow tube (4) is sealed by a flexible sealing method.

3. The watertightness test structure for carbon fiber cable anchors as described in claim 1, characterized in that: The sealing assembly (2) is provided with a positioning hole (28) and a pressure rod (7). One end of the pressure rod (7) extends into the positioning hole (28) and is connected, while the other end is connected to the inner wall of the end cap (5).

4. The watertightness test structure for carbon fiber cable anchors as described in claim 2, characterized in that: The sealing assembly (2) includes an outer sealing plate (21), a middle sealing plate (22), a damage prevention plate (23), and an inner sealing plate (24). The outer sealing plate (21), the middle sealing plate (22), the damage prevention plate (23), and the inner sealing plate (24) are arranged sequentially from right to left in the pre-embedded pipe (1).

5. The watertightness test structure for carbon fiber cable anchors as described in claim 4, characterized in that: The middle sealing plate (22), the damage prevention plate (23) and the inner sealing plate (24) are respectively provided with a second through hole (26), and the outer sealing plate (21) is provided with a screw hole (27).

6. The watertightness test structure for carbon fiber cable anchors as described in claim 4, characterized in that: The outer sealing plate (21) and the damage prevention plate (23) are made of plastic, and the middle sealing plate (22) is made of polyurethane foam.

7. The watertightness test structure for carbon fiber cable anchors as described in claim 1, characterized in that: The pre-embedded pipe (1) is provided with a first countersunk hole (11) to limit the installation of the sealing component (2). One end of the pre-embedded pipe (1) is provided with an external thread and the other end is provided with an internal thread. The pre-embedded pipe (1) is threaded to the end cap (5) through the external thread and to the clamping device (3) through the internal thread.

8. The watertightness test structure for carbon fiber cable anchors as described in claim 1, characterized in that: The end cap (5) is coaxially provided with a threaded through hole (51), a limiting countersunk hole (52) and a blind hole (53). The end cap (5) is provided with a second bolt (8). The end cap (5) is threadedly connected to the second bolt (8) through the threaded through hole (51). The end cap (5) is connected to the pressure rod (7) through the limiting countersunk hole (52). The end cap (5) is connected to the hollow tube (4) through the blind hole (53).

9. The installation method of the carbon fiber cable anchor watertightness test structure as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. The inner sealing plate (24), the damage prevention plate (23), the middle sealing plate (22) and the outer sealing plate (21) are fastened together in sequence using the first bolt (6) to form a sealing assembly (2); S2. Tighten the external thread end of the pre-embedded pipe (1) to the internal thread of the end cap (5) and apply sealant to the thread before installation to ensure the sealing of the threaded joint. S3. Position the pressure rod (7) in the limiting countersunk hole (52) of the end cap (5); S4. Pass the hollow tube (4) through the first through hole (25) through the sealing assembly (2) and achieve hole-shaft mating with the blind hole (53) of the end cap (5); install the sealing assembly (2) along the axis of the embedded tube (1) to the first countersunk hole (11) of the embedded tube (1), while ensuring that the pressure rod (7) and the sealing assembly (2) achieve hole-shaft mating. S5. Install the clamping device (3), and apply sealant to both the external thread of the clamping device (3) and the internal thread of the embedded pipe (1) before installation to ensure a tight seal at the threaded connection. S6. Install the second bolt (8), tighten the second bolt (8) in stages with the same torque wrench, and transfer the preload of the second bolt (8) to the sealing assembly (2) through the pressure bar (7) to ensure that the sealing assembly (2) and all hollow tubes (4) are sealed.

10. The test method for the watertightness test structure of the carbon fiber cable anchor as described in claim 1 or 2, characterized in that, Includes the following steps: S7. Place the temperature and humidity sensor (9) inside the hollow tube (4) and seal the exposed port of the hollow tube (4) with flexible sealant; S8. Connect the interface of the temperature and humidity sensor (9) to the data acquisition unit, monitor the humidity data, and then immerse the water tightness test device with the temperature and humidity sensor (9) installed in water for 3 days. S9. If the daily humidity change does not exceed 1% during the testing period, and the relative humidity change within 3 days does not exceed 3%, then the sealing effect of the sealing device is deemed qualified; otherwise, it is deemed unqualified.

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