Finished cable beam end anchorage area combined sealing structure and preparation method

Abstract

The application discloses a finished cable beam end anchorage zone combined sealing structure and a preparation method, and the sealing structure comprises an anchorage device, a sealing cylinder, a cable body, a waterproof cover and a pre-buried pipe, one end of the pre-buried pipe is connected with the anchorage device, the other end of the pre-buried pipe is connected with the waterproof cover, the sealing cylinder is arranged in the pre-buried pipe, and the cable body is connected with the anchorage device after penetrating through the waterproof cover, the sealing cylinder and the pre-buried pipe. In the application, the combined structure of the HDPE bonding ring A and the bonding ring B and the combined structure of the polyurea protective layer A and the protective layer B can form double sealing protection, meanwhile, the sealing condition of the cable body and the waterproof cover exposed on the bridge surface can be observed, the sealing condition of the cable body sealing structure in the pre-buried pipe is indirectly monitored, and the problem that the cable body sealing structure is inconvenient to monitor in the pre-buried pipe is solved.

Description

Technical Field

[0001] This invention belongs to the field of bridge cable technology, and particularly relates to the combined sealing structure and preparation method of the anchorage zone of the finished cable beam end. Background Technology

[0002] Within the pre-embedded pipes at the ends of bridge cables, water seepage can occur in the anchorage area due to various reasons, including dynamic loads on the cable body causing seal failure, thermal expansion and contraction of the cable's PE material leading to seal failure, condensation buildup due to temperature changes, or a humid environment. This can result in corrosion damage to the prestressed steel wires or strands within the cable. Currently, the sealing structure between the cable body and the anchorage uses threaded sealant, rubber sealing rings, sealing putty, and heat-shrink sleeves. Alternatively, the sealing at the junction of the cable body and the pre-embedded pipe at the beam end can be improved by using a combination of waterproof covers or adding aluminum alloy airbags.

[0003] The closest patents to the sealing structure at the connection between the cable body and the anchor are CN202120972100.6 "A Cable Sealing Structure and a Cable with a Sealing Structure" and CN201811002946.6 "A Waterproof Device for Thermal Expansion and Contraction of the Outer PE Sheath of a Cable". The technology described is as follows: the upper part adopts a Haver-type sealing cover or a two-half waterproof umbrella structure and is fixed and sealed to the cable body with sealing putty, water-swellable rubber sealing strip, silicone sealant or polysulfide sealant. The lower part adopts a limiting ring and sealing ring made of elastic materials such as rubber or a sliding inner liner that slides freely on the cable sealing cylinder with the thermal expansion and contraction of the PE sheath, so as to perform double sealing treatment. This method addresses the sealing and waterproofing issues at the connection between the cable and the anchorage under dynamic loads or thermal expansion and contraction conditions to some extent. However, the aforementioned sealing materials inevitably have a short lifespan due to aging, failing to meet the 20-year design service life of cable stays stipulated in JTG / T3365-01 "Design Specification for Highway Cable-Stayed Bridges". Furthermore, it does not cover waterproofing measures at the threaded connections between the anchor cup and the sealing cylinder, or between the sealing cylinder and the segmented connecting cylinder within the cable anchorage components, thus failing to guarantee sealing requirements under condensation or humid environmental conditions.

[0004] The closest patents to the sealing structure at the connection between the cable body and the pre-embedded pipe at the beam end are CN 215104687 U "A Waterproof Cover for Cables", CN201710197084.6 "Flexible Waterproof Device for Bridge Cables and Method for Achieving Waterproof Sealing of Cable Body Waterproof Cover", and CN202223503306.8 "Double Flexible Air-Sealing Structure of Lower Anchorage Zone at Cable Beam End". These patents employ a Haver-type pressure ring and sealing ring sealing structure, or a single-sided open integral rubber waterproof cover with sealing material or rubber strips filled into the groove at the cable connection, or a two-half ring structure with adhesive injection grooves inside the pressure ring for sealing. However, all of these sealing materials inevitably suffer from aging and short lifespan. Furthermore, the connection of the two-half structure carries a risk of water leakage after the sealing structure fails. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a combined sealing structure and preparation method for the anchorage zone of a finished cable beam end, which can solve the problems of corrosion and waterproofing in the anchorage zone of the bridge end, as well as the inconvenience of monitoring the cable sealing structure inside the pre-embedded pipe.

[0006] The present invention is achieved through the following technical solutions.

[0007] The present invention provides a combined sealing structure for the anchorage zone of a finished cable beam, comprising an anchor, a sealing cylinder, a cable body, a waterproof cover, and a pre-embedded pipe. One end of the pre-embedded pipe is connected to the anchor, and the other end of the pre-embedded pipe is connected to the waterproof cover. The sealing cylinder is disposed inside the pre-embedded pipe, and the cable body passes through the waterproof cover, the sealing cylinder, and the pre-embedded pipe before being connected to the anchor.

[0008] Preferably, an adhesive ring A is provided at the connection between the cable body and the sealing cylinder port, and an adhesive ring B is provided at the connection between the cable body and the waterproof cover port.

[0009] Preferably, the anchor, sealing cylinder and cable are covered with a protective layer A.

[0010] Preferably, the waterproof cover is covered with a protective layer B.

[0011] Preferably, the bonding ring A and bonding ring B are HDPE bonding rings.

[0012] Preferably, the protective layer A and the protective layer B are polyurea protective layers.

[0013] The method for preparing the composite sealing structure of the anchorage zone at the end of the finished cable beam includes the following steps:

[0014] S1: Grind a 10-15cm section of the cable body centered on the connection between the cable body and the sealing cylinder port until the cable body is rough. Then heat the cable body and then weld it circumferentially, building up the height to no less than 2 / 3 of the size of the sealing cylinder port 2. Then use a snap-fit ​​two-half cone-shaped molding mold to press down along the sealing cylinder port until the cone surface of the molding mold presses against the sealing cylinder port, and then demold to complete the preparation of the bonding ring A. The bonding ring B needs to be prepared on-site after the cable construction is completed and the waterproof cover is installed. The preparation method is the same as that of the bonding ring A.

[0015] S2: Grind a 20-40cm section of the cable body centered on the connection between the cable body and the sealing cylinder port until the cable body is rough. Then heat the cable body. Next, wrap the starting ends of the protective layer A with a protective film. Spray the protective layer circumferentially from the ground position on the cable body towards the anchor end face. After the coating is completely dry, smooth out any unevenness at the starting ends of the spraying to complete the preparation of the protective layer A. The protective layer B needs to be prepared at the application site after the cable construction is completed and the waterproof cover is installed. The preparation method is the same as that of the protective layer A.

[0016] Preferably, before spraying, the protective layer A or the protective layer B needs to be pre-coated with an epoxy-modified polyurethane primer on the surface of the sealing cylinder or waterproof cover. The protective layer A and the protective layer B are prepared using components A and B, and the solid content of each is not less than 99%.

[0017] Preferably, component A comprises diphenylmethane diisocyanate and a prepolymer of diphenylmethane diisocyanate and polyether polyol, wherein the concentration percentage is 45-55:55-45; component B comprises polyether polyamine and diethyltoluene diamine, wherein the concentration percentage is 60-80:40-20; and the volume ratio of component A to component B is 1:1.

[0018] Preferably, in steps S1 and S2, the heating cable body is heated to 80-120°C, the coating thickness of the protective layer A and the protective layer B is 2-4 mm, and in step S1, the circumferential welding height is not less than 2 / 3 of the port size of the sealing cylinder 2.

[0019] The beneficial effects of this invention are as follows:

[0020] The structure of HDPE bonding ring A and bonding ring B, as well as the treatment of polyurea protective layer A and protective layer B in this invention, can form a double-seal protection. At the same time, the sealing condition of the cable body sealing structure inside the pre-embedded pipe can be indirectly monitored by observing the sealing condition between the exposed cable body and the waterproof cover on the bridge deck, thus solving the problem of inconvenient monitoring of the cable body sealing structure inside the pre-embedded pipe. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the structure of the bonding ring B of the present invention;

[0023] In the diagram: 1-Anchor, 2-Sealing cylinder, 3-Cable body, 4-Adhesive ring A, 5-Protective layer A, 7-Adhesive ring B, 8-Protective layer B, 9-Waterproof cover, 10-Embedded pipe. Detailed Implementation

[0024] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0025] Example 1:

[0026] like Figure 1 , 2 As shown, the prefabricated cable beam end anchorage zone combined sealing structure includes an anchor 1, a sealing cylinder 2, a cable body 3, a waterproof cover 9, and a pre-embedded pipe 10. One end of the pre-embedded pipe 10 is connected to the anchor 1, and the other end of the pre-embedded pipe 10 is connected to the waterproof cover 9. The sealing cylinder 2 is set inside the pre-embedded pipe 10. The cable body 3 passes through the waterproof cover 9, the sealing cylinder 2, and the pre-embedded pipe 10 before being connected to the anchor 1.

[0027] An adhesive ring A4 is provided at the connection between the cable body 3 and the port of the sealing cylinder 2, which improves the corrosion resistance of the beam end anchorage area.

[0028] The anchor 1, sealing cylinder 2 and cable body 3 are covered with a protective layer A5 to achieve overall protection.

[0029] An adhesive ring B7 is provided at the connection between the cable body 3 and the waterproof cover 9, which improves the waterproof performance of the beam end anchorage area. A protective layer B8 is provided on the outside of the waterproof cover 9.

[0030] The bonding rings A4 and B7 are HDPE bonding rings. This design extends the lifespan of the cable body 3 and provides seamless flow control and seepage prevention. The bonding rings A4 and B7 on the same cable body 3 further facilitate a smooth transition at the joint, resolving the issue of bulging easily occurring at corners when applying protective layers A5 and B8.

[0031] The protective layers A5 and B8 are polyurea protective layers. The fully enclosed sealing structure of the polyurea protective layer utilizes the adhesive, anti-aging, and high elongation properties of polyurea to solve the problems of seepage prevention and sealing at joints and threaded connections under conditions of permissible elongation variations in the cable body, resulting in a longer sealing life. Simultaneously, it provides full-coverage polyurea protection for the anchorage area and the waterproof cover area at the cable beam end. Furthermore, protective layer B8 effectively solves the problem of aging and cracking of the waterproof cover 9. The continuous, integral polyurea protective layer composed of protective layers A5 and B8 further improves the corrosion resistance of the anchorage area at the beam end and the waterproof performance of the waterproof cover 9.

[0032] The method for preparing the composite sealing structure of the anchorage zone at the end of the finished cable beam includes the following steps:

[0033] S1: The bonding ring A4 is prepared before leaving the factory. First, use a grinder to grind the 12cm section of the cable body 3 centered on the connection between the cable body 3 and the port of the sealing cylinder 2, grinding circumferentially until the cable body 3 is rough. Then, use a hot air gun to heat the cable body 3 to 100℃, making the surface of the cable body 3 sticky. Then, use a handheld plastic welding machine to circumferentially weld, building up to a height of not less than 2 / 3 of the port size of the sealing cylinder 2. Then, use a snap-fit ​​two-half cone-shaped molding mold to press down along the port of the sealing cylinder 2 until the cone surface of the molding mold presses against the port of the sealing cylinder 2, and then demolding is completed, completing the preparation of the bonding ring A4. After demolding, if there is an edge at the mold joint, it can be smoothed with a knife. The bonding ring B7 needs to be prepared at the application site, after the cable construction is completed and the waterproof cover 9 is installed. The preparation method is the same as that of the bonding ring A4.

[0034] S2: The protective layer A5 of the anchor 1, sealing cylinder 2, and cable body 3 is sprayed before leaving the factory. First, use a grinder to grind a 30cm section of the cable body 3 centered on the connection between the cable body 3 and the port of the sealing cylinder 2, and grind circumferentially until the cable body 3 is rough. Then, use a hot air gun to heat the cable body 3 to 100°C, making the surface of the cable body 3 sticky. Next, wrap the starting ends of the protective layer A5 spraying with a protective stretch film. Use a polyurea spraying device to spray circumferentially from the ground position on the cable body 3 to the end face of the anchor 1. After the coating is completely dry, smooth out any unevenness at the starting ends of the spraying to complete the preparation of the protective layer A5. The protective layer B8 needs to be prepared at the application site after the cable construction is completed and the waterproof cover 9 is installed. The preparation method is the same as that of the protective layer A5.

[0035] Before spraying, the protective layer A5 or protective layer B8 needs to be pre-coated with epoxy-modified polyurethane primer or other materials that can bond with both metal and polyurea materials to ensure that there are no gaps at the bonding surface after the protective layer A5 and protective layer B8 are formed, thereby further improving the sealing performance. The protective layer A5 and protective layer B8 are made of polyurea material prepared from components A and B, with a solid content of not less than 99%, and after being aged by QUV irradiation for 10,000 hours, the tensile strength and elongation at break retention rate are not less than 95%.

[0036] Component A comprises diphenylmethane diisocyanate and a prepolymer of diphenylmethane diisocyanate and polyether polyol, wherein the concentration percentage is 50:50; Component B comprises polyether polyamine and diethyltoluene diamine, wherein the concentration percentage is 70:30; the volume ratio of component A to component B is 1:1.

[0037] The coating thickness of the protective layer A and the protective layer B is 3 mm.

[0038] Example 2:

[0039] The sealing structure and preparation method are basically the same as in Example 1, except that: in step S1 of the preparation method, the 10cm section of the cable body 3 centered on the connection point with the port of the sealing cylinder 2 is polished with a grinder until the cable body 3 is rough, and then the cable body 3 is heated to 80°C with a hot air gun; in step S2, the 20cm section of the cable body 3 centered on the connection point with the port of the sealing cylinder 2 is polished with a grinder until the cable body 3 is rough, and then the cable body 3 is heated to 80°C with a hot air gun; the coating thickness of protective layer A and protective layer B is 2mm.

[0040] Component A comprises a prepolymer of diphenylmethane diisocyanate and diphenylmethane diisocyanate with polyether polyol, wherein the concentration percentage is 45:55; Component B comprises polyether polyamine and diethyltoluene diamine, wherein the concentration percentage is 60:40; the volume ratio of component A to component B is 1:1.

[0041] Example 3:

[0042] The sealing structure and preparation method are basically the same as in Example 1, except that: in step S1 of the preparation method, the 15cm section of the cable body 3 centered on the connection point with the port of the sealing cylinder 2 is polished with a grinder until the cable body 3 is rough, and then the cable body 3 is heated to 120°C with a hot air gun; in step S2, the 40cm section of the cable body 3 centered on the connection point with the port of the sealing cylinder 2 is polished with a grinder until the cable body 3 is rough, and then the cable body 3 is heated to 120°C with a hot air gun; the coating thickness of protective layer A and protective layer B is 4mm.

[0043] Component A comprises a prepolymer of diphenylmethane diisocyanate and diphenylmethane diisocyanate with polyether polyol, wherein the concentration percentage is 55:45; Component B comprises polyether polyamine and diethyltoluene diamine, wherein the concentration percentage is 80:20; the volume ratio of component A to component B is 1:1.

[0044] The sealing structures prepared in Examples 1-3 were subjected to a simulated 10,000-hour continuous water spray test, and the data obtained are shown in the table below.

[0045]

[0046] After 10,000 hours of continuous water spray test, the humidity inside the pre-embedded pipe 10 and the cable anchor 1 in Examples 1-3 was below 60%, which met the usage requirements.

[0047] Bonding rings A4 and B7, and protective layers A5 and B8 are installed on the same cable body 3. This not only serves as a double seal, but also facilitates indirect monitoring of the sealing condition between the cable body HDPE and the sealing components inside the pre-embedded pipe 10 by observing the sealing condition of the exposed bonding ring B7 and protective layer B8 on the bridge deck.

Claims

1. A method for preparing a combined sealing structure for the anchorage zone of a finished cable-stayed beam, characterized in that: The combined sealing structure of the anchorage area of ​​the finished cable beam includes an anchor (1), a sealing cylinder (2), a cable body (3), a waterproof cover (9), and a pre-embedded pipe (10). One end of the pre-embedded pipe (10) is connected to the anchor (1), and the other end of the pre-embedded pipe (10) is connected to the waterproof cover (9). The sealing cylinder (2) is set inside the pre-embedded pipe (10). The cable body (3) passes through the waterproof cover (9), the sealing cylinder (2), and the pre-embedded pipe (10) and is then connected to the anchor (1). An adhesive ring A (4) is provided at the connection between the cable body (3) and the sealing cylinder (2), and an adhesive ring B (7) is provided at the connection between the cable body (3) and the waterproof cover (9). The anchor (1), sealing cylinder (2) and cable body (3) are covered with a protective layer A (5); The waterproof cover (9) is covered with a protective layer B (8); The bonding ring A (4) and bonding ring B (7) are HDPE bonding rings; The protective layer A (5) and the protective layer B (8) are polyurea protective layers; The preparation method includes the following steps: S1: Grind the 10-15cm section of the cable body (3) centered on the connection between the cable body (3) and the port of the sealing cylinder (2) until the cable body (3) is rough. Then heat the cable body (3) and then weld it in a circumferential manner. The height should be no less than 2 / 3 of the port size of the sealing cylinder (2). Then use a snap-fit ​​two-half cone-shaped molding mold to press down along the port of the sealing cylinder (2) until the cone surface of the molding mold presses against the port of the sealing cylinder (2) and then demold it to complete the preparation of the bonding ring A (4). The bonding ring B (7) needs to be prepared at the application site after the cable construction is completed and the waterproof cover (9) is installed. The preparation method is the same as that of the bonding ring A (4). S2: Grind the cable body (3) for 20-40cm from the connection point between the cable body (3) and the sealing cylinder (2) until the cable body (3) is rough. Then heat the cable body (3). Next, wrap the starting ends of the protective layer A (5) with a protective film. Spray the coating around the anchor (1) end face along the grinding position on the cable body (3). After the coating is completely dry, smooth the uneven ends of the starting ends of the coating to complete the preparation of the protective layer A (5). The protective layer B (8) needs to be prepared at the application site after the cable construction is completed and the waterproof cover (9) is installed. The preparation method is the same as that of the protective layer A (5).

2. The method for preparing the combined sealing structure of the anchorage zone at the end of the finished cable beam as described in claim 1, characterized in that: Before spraying, the protective layer A (5) or the protective layer B (8) needs to be coated with epoxy modified polyurethane primer on the surface of the sealing cylinder (2) or the waterproof cover (9). The protective layer A (5) and the protective layer B (8) are prepared using component A and component B, and the solid content of each is not less than 99%. Component A comprises diphenylmethane diisocyanate and a prepolymer of diphenylmethane diisocyanate and polyether polyol, wherein the concentration percentage is 45-55:55-45; Component B comprises polyether polyamine and diethyltoluene diamine, wherein the concentration percentage is 60-80:40-20; the volume ratio of component A to component B is 1:

1.

3. The method for preparing the combined sealing structure of the anchorage zone at the end of the finished cable beam as described in claim 1, characterized in that: In step S2, the heating cable (3) is heated to 80-120°C, and the coating thickness of the protective layer A and the protective layer B is 2-4 mm.

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