Super-large-adjustment-amount inhaul cable anchorage device structure for cable-stayed-suspension cable cooperative bridge

Abstract

The invention relates to a super-large-adjustment-amount inhaul cable anchorage device structure for a cable-stayed-suspension cable cooperative bridge, and belongs to the technical field of cable body anchoring. Which comprises an anchor cup and a nut screwed outside the anchor cup, and is characterized in that an anchoring conical cavity, a middle transition cavity, a protection conical cavity and a sealing cavity which are coaxially distributed are arranged in the anchor cup, the anchoring conical cavity and the protection conical cavity are located on the front side and the rear side of the middle transition cavity respectively, and the conical directions of the anchoring conical cavity and the protection conical cavity are opposite; the cable body steel wire bundle sequentially penetrates through the sealing cavity, the protection conical cavity and the middle transition cavity in parallel from back to front and then is scattered in a conical shape to be anchored in the anchoring conical cavity. The invention provides a novel stay cable anchorage device structure which integrates a connecting cylinder and an anchorage device into a whole and is combined by a straight cavity and a plurality of sections of conical cavities and has an ultra-long adjusting amount, and the adjusting length of a nut on an anchor cup is obviously prolonged.

Description

Technical Field

[0002] The present invention relates to an anchoring structure of a cable, and particularly to an anchor structure with adjustable length. Background Art

[0004] A cable-stayed bridge mainly consists of four major parts: stay cables, towers, main girders, and auxiliary structures. Among them, the main girders, stay cables, and bridge towers are the main load-bearing components. Cable-stayed bridges are aesthetically pleasing, have a strong spanning ability, are convenient for construction, and do not require anchorages. However, as the span of cable-stayed bridges increases, some problems become more prominent, mainly including: the height of the bridge tower increases, the problem of wind resistance stability becomes prominent, and the construction difficulty and project cost increase; the axial pressure of the main girder increases, and the problem of buckling stability becomes prominent; the length of the longest stay cable increases, the sag effect of the stay cable becomes more obvious, and the axial stiffness of the stay cable decreases; but the excessive axial pressure of the main girder is the primary factor restricting the development of its span, and the above problems are also the key reasons hindering the further increase of the span of cable-stayed bridges. A suspension bridge mainly consists of four major parts: a cable system, towers, stiffening girders, and auxiliary structures. Suspension bridges have advantages such as a large spanning ability and a beautiful bridge shape. However, as the span continues to increase, its structural flexibility continues to increase. In addition, as the span increases, the engineering quantity and construction technical difficulty of the suspension bridge anchorages also increase.

[0005] The cable-stayed suspension cooperative system combines the advantages of both suspension bridges and cable-stayed bridges and is a powerful competitive structural form for long-span bridges. A cable-stayed suspension cooperative system bridge mainly consists of four major parts: a cable system, towers, main girders, and auxiliary structures. Among them, the anchorages, bridge towers, main cables, stay cables, and main girders are the main force-bearing structures. The advantages of this system compared with suspension bridges and cable-stayed bridges are as follows: 1) The cable-stayed suspension cooperative system bridge consists of a cable-stayed bridge part and a suspension bridge part. Unlike suspension bridges, all loads are transmitted to the foundation through the main cable. The loads borne by the cable-stayed bridge part are directly transmitted to the foundation through the main tower, reducing the tension of the main cable, and the scale, construction difficulty, and project cost of the anchorages also decrease accordingly, making it possible to construct the bridge structure on soft soil foundations; 2) Compared with cable-stayed bridges, the cantilever construction length and the height of the bridge tower of the cooperative system are much smaller, which improves the wind resistance stability during the construction process and in the completed bridge state of the structure while reducing the construction difficulty and project cost; 3) The main girder adopts a composite girder form, which can make full use of the structural characteristics of each part to improve the structural performance. For example, if the cable-stayed part adopts a prestressed concrete girder or a composite girder, it can make full use of the axial pressure of the main girder as prestress while improving the overall stiffness and stability of the structure. The suspension part adopts a lightweight steel box or steel truss girder, reducing the engineering quantity of the main girder, main cable, suspension cables, and anchorages; 4) The length of the suspension part decreases, and the stiffness is significantly improved. Therefore, the aerodynamic stability of the entire bridge is significantly improved.

[0006] Therefore, the cable-stayed and suspension cooperative system combines the advantages of both suspension bridges and cable-stayed bridges. Its tower height, axial pressure of the main girder, and cantilever construction length are smaller than those of a cable-stayed bridge with the same span, while its stiffness and wind resistance stability are better than those of a suspension bridge with the same span. For super-long-span cable-stayed and suspension cooperative system bridges, due to the consideration of the action of the second-stage permanent load, when hoisting the steel girder in the suspended area, according to the installation methods of the suspenders and the main girder of the suspension bridge, the elevation of the main girder is higher than that at the completed bridge state, and it is difficult to install and close the main girder. The main span of the Third Bosphorus Bridge is 1,408 m and it is located in the Bosphorus Strait in Turkey. The main girder uses a steel box girder. In order to adjust the elevation of the main girder in the suspended area during the construction process, a large number of temporary suspenders with lengths longer than the permanent suspenders are used. By adjusting the stress-free length of the temporary suspenders, the alignment during the installation of the main girder is controlled, enabling the main girder to be installed section by section. Another option is to choose to close the joint in the crossover area. When the closure joint of the main girder is located in the crossover area, it is first necessary to clarify the specific location of the closure joint. When the closure joint is between the bridge tower and the crossover area, the stay cables on the suspended side of the main girder cannot be tensioned. Therefore, the end of the suspended side of the main girder generally deflects downward significantly, and the rotation angle of the main girder end is large. So, the closure joint tends to open downward. When choosing the closure joint between the crossover area and the mid-span, since some of the suspenders on the cable-stayed side cannot be tensioned and the upward deflection of the suspended side is large, the closure joint tends to open upward. Therefore, there must be an optimal closure joint in and near the crossover area, and an interpolation calculation method is used to find the optimal closure joint. Under the condition of the optimal closure joint, the stay cables and suspenders near the closure joint need to have a larger adjustment amount to meet the requirements of the construction closure. Therefore, for a super-long-span cable-stayed and suspension cooperative system of 2,300 m, it is necessary to develop ultra-long adjustment amount stay (suspender) cable anchorages and grouting and anchoring methods with longer adjustment lengths to ensure that the adjustment amount of the anchoring systems of the stay cables and suspenders in the transition area of the super-long-span cable-stayed and cooperative system meets the engineering requirements, and the anchoring efficiency is not less than 100%.

[0007] The cold-cast anchor anchoring system for stay cables has been verified by engineering practice to have high anchoring efficiency, good anti-fatigue performance, and stable and reliable long-term service performance. The core components of this anchoring structure are the anchor cup and the nut. The inner part of the anchor cup is an inner conical cavity with a cone angle of 5° - 7°. The outer surface of the anchor cup is a trapezoidal thread, and the inner surface of the nut is a trapezoidal thread. The trapezoidal thread has a large diameter and pitch, providing strong load-bearing capacity to ensure stability and accuracy under the long-term load-bearing conditions of the stay cables; the pitch range of the trapezoidal thread is wide and can be selected according to the specifications of the stay cables. The excellent mechanical properties and wear resistance of the trapezoidal thread enable it to maintain stable performance in the extreme service environment of the stay cables, while reducing maintenance costs.

[0008] When the stay cable bears the load, the inner wall of the anchor cup will exert a squeezing force on the anchoring cone formed by the cold-cast material and the steel wire, generating a circumferential constraint on the cold-cast filler and the steel wire material, and realizing the anchoring of the steel wire in the anchor cup. When the stay cable bears the load, the anchor cup passes through the embedded pipe on the bridge or the anchor backing plate on the anchor tie plate, and then the nut is installed. The nut bears pressure on the anchor backing plate, and then the stay cable is tensioned and adjusted to ensure that the alignment of the cable-stayed bridge and the cable force of the stay cable reach the designed state, realizing the connection and load transfer between the stay cable and the bridge tower and the beam. During the construction and tensioning process of the stay cable, the length and tension of the stay cable are adjusted by screwing the nut. For example, Figure 1 , where △L is the length of the left and right adjustment of the nut.

[0009] When the stay cable bears the load, since the inner wall of the anchor cup is conical, a horizontal force is generated, causing the casting to slip. The inner cone angle of the anchor cup is a key parameter. For the anchoring structure with an ultra-long adjustment amount, it is necessary to extend the length of the anchor cup to increase the adjustment length. When the outer diameter of the anchor is unchanged, extending the length of the anchor cup will cause the inner cone angle of the anchor to decrease, resulting in an increase in the shrinkage amount of the anchor body when the stay cable bears the load and a reduction in the anchoring reliability. SUMMARY OF THE INVENTION

[0011] Aiming at the above technical status quo, the purpose of the present invention is to provide an anchor structure for the cable body, which has a longer length adjustment amount.

[0012] The technical solution adopted by the present invention to solve the above problems is as follows: An ultra-large adjustment amount cable anchor structure for a cable-stayed and suspension cooperative bridge, including an anchor cup and a nut, the nut is screwed outside the anchor cup, and it is characterized in that: the interior of the anchor cup includes an axially distributed anchoring conical cavity, an intermediate transition cavity, a protective conical cavity and a sealing cavity. The anchoring conical cavity and the protective conical cavity are respectively located on the front and rear sides of the intermediate transition cavity, and their conical directions are opposite. The cable body steel wire bundle passes through the sealing cavity, the protective conical cavity and the intermediate transition cavity in parallel from back to front, and then spreads out in a conical shape and is anchored in the anchoring conical cavity.

[0013] Preferably, the axial length of the intermediate transition cavity is 50 mm to 100 mm, and a positioning ring is arranged in the intermediate transition cavity, and the cable body steel wire bundle passes through the positioning ring.

[0014] Preferably, the inner cone angle of the anchoring conical cavity is 5° to 10°, and the axial length is 300 mm to 700 mm. The anchoring filler is cast in the cavity to fix the spread steel wire bundle.

[0015] Preferably, the inner cone angle of the protective conical cavity is 2° to 3°, and the axial length is 300 mm to 700 mm. The filler is cast in the cavity to fix the cable body steel wire bundle. A positioning ring is arranged inside the protective conical cavity, and the cable body steel wire bundle passes through the positioning ring. The inner hole diameter of the positioning ring is 1.0 - 1.1 times the diameter of the cable body steel wire bundle.

[0016] Preferably, an annular groove is provided on the inner wall of the protective conical cavity, and the positioning ring is arranged in the annular groove.

[0017] Preferably, a sealing ring is arranged in the sealing cavity, and a sealing pressure ring is further arranged at the rear side of the sealing ring. The sealing ring, the sealing pressure ring and the sealing cavity are in threaded engagement. The sealing ring and the sealing pressure ring respectively have central holes for the cable body to pass through. The inner diameter of the central hole of the sealing pressure ring is 1.01 - 1.05 times the diameter of the cable body, and the inner diameter of the central hole of the sealing ring is 0.95 - 1.05 times the diameter of the cable body.

[0018] Preferably, the front end of the sealing ring is conical and is screwed into the protective conical cavity forward. The rear end of the sealing pressure ring exposes out of the sealing cavity and has a conical shape gradually decreasing from front to back. A shrinkage sleeve is further wrapped around the outer periphery of the fitting clearance between the sealing pressure ring and the cable body.

[0019] Preferably, the shrinkage sleeve includes a heat shrinkage sleeve and a cold shrinkage sleeve. Description of the Drawings

[0021] Figure 1 is a schematic structural diagram of an existing cable body anchor;

[0022] Figure 2 is a schematic structural diagram of the stay cable anchor of the embodiment of the present invention

[0023] In the figure, nut 1, anchor cup 2, waterproof sealing sleeve 3, cable body 4, anchor plate 5, anchoring filler 6, steel wire 7, phenolic resin positioning ring 8, nylon positioning ring 9, silicone rubber sealing ring 10, sealing pressure ring 11, shrinkage sleeve 12. Detailed Embodiments

[0025] The present invention will be further described in detail below with reference to the accompanying drawings. The embodiments are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention. The textual description in this embodiment corresponds to the accompanying drawings, and the description of directions is also based on the accompanying drawings, and should not be construed as a limitation to the protection scope of the present invention.

[0026] The present invention proposes a novel stay cable anchor structure integrating a connecting cylinder and an anchor, with a combination of a straight cavity + multi-segment conical cavities and an ultra-long adjustment amount. Its structure is as Figure 2 shown. In the figure, the left side is the front end and the right side is the rear end. The structure is described as follows:

[0027] The anchor device includes a nut 1 and an anchor cup 2. The nut 1 has a trapezoidal internal thread, and the anchor cup 2 has a trapezoidal external thread. The nut 1 is screwed outside the anchor cup 2. Adjusting the position of the nut 1 on the anchor cup 2 can realize the adjustment of the length of the anchor system. The anchor cup 2 has five chambers distributed coaxially in the front and rear.

[0028] The frontmost part of the inner cavity of the anchor cup is a straight-section cavity with an internal thread in the first section, which is used to install a traction tensioning device during the construction of the stay cable. It is also called the tensioning thread cavity section. The length of this section is generally 100 mm to 250 mm.

[0029] The second section of the inner cavity of the anchor cup is a conical cavity with an inner cone angle of 5° to 6°, and the length is 300 mm to 700 mm. This section is the anchoring and bearing section. The front end of the cone is the large end, and the rear end is the small end. The steel wire bundle is distributed in a conical shape and spreads out. An anchor plate 5 with a thickness of 20 mm to 25 mm and an external taper is installed at the front end. The anchor plate 5 is provided with perforations to facilitate the passing of the steel wire 7 and upsetting and anchoring. The external taper of the anchor plate 5 is consistent with the internal taper of the second section of the chamber. After installing the anchor plate 5, an anchoring filler 6 (a mixture of epoxy resin, steel balls, and chlorite) is poured into this conical section. After curing, a cone is formed to realize the anchoring and bearing of the stay cable steel wire bundle.

[0030] The third section of the inner cavity of the anchor cup is a straight-section cavity (transition cavity), which is used to install a phenolic resin positioning ring 8 with good wear resistance, high strength, good corrosion resistance, and high temperature resistance to prevent the steel wires scattered in the second section from directly contacting the inner wall of the anchor device. The length is 50 mm to 100 mm. Phenolic resin has excellent wear resistance and can be used for a long time without being easily worn under the high load and friction environment of the stay cable. It also has high mechanical strength and can withstand large radial and axial loads. Phenolic resin has good heat resistance and can remain stable and not easily deform in a high temperature environment. It can effectively position the outermost steel wires of the cable body in the anchor cup from the straight section to the divergent section of the anchoring area and does not change during the anchor pouring and heating process.

[0031] The fourth section of the inner cavity of the anchor cup is a conical cavity (protective conical cavity) with an inner cone angle of 2° to 3°. The conical direction is opposite to that of the second conical section, and the length is 300 mm to 700 mm. This section replaces the connecting cylinder of the conventional stay cable anchor in the past and serves as a protective section. It is mainly used for pouring anchor epoxy resin and diabase salt mixture. Steel balls are not required for the filling material in this section. The function of this section is to protect the steel wire bundle. Generally, it is advisable for the filling material to have a relatively low elastic modulus), so as to achieve the protection of the steel wire in the transition section of the stay cable. Setting the taper can ensure that the epoxy resin sealing and protective material under the bearing condition of the stay cable bears less extrusion stress and tensile stress, avoiding cracking and better protecting the stay cable steel wire. An annular groove is machined in the middle section of the cone for installing the nylon positioning ring 9 of the cable body. The nylon positioning ring 9 needs to be machined to adapt to the shape of the inner wall of the anchor cup. And there is slight movement at this position during the anchor pouring process. The nylon material is wear-resistant and self-lubricating, with an extremely low friction coefficient, which can reduce the damage to the steel wire. In addition, the machining geometric accuracy is relatively high. The inner diameter of the nylon positioning ring is 1.0 to 1.1 times the diameter of the bare stay cable, and the outer diameter is the same as the inner diameter of the annular groove.

[0032] The fifth section of the inner cavity of the anchor cup is a straight section cavity. The inner diameter of the cavity is the same as the large diameter of the cone, and an internal thread is provided. It is threadedly engaged with a sealing gland with an external thread and a central hole. The diameter of the central hole of the sealing gland 11 is 1.01 to 1.05 times the diameter of the stay cable body. The rear end of the sealing gland 11 is conical, which is convenient for installing the shrinkage sleeve 12 at the transition position between the sealing gland 11 and the stay cable body. The shrinkage sleeve 12 includes a heat shrinkage sleeve and a cold shrinkage sleeve.

[0033] A silicone rubber sealing ring 10 is provided at the front end of the sealing gland 11. The inner diameter of the silicone rubber sealing ring 10 is 0.95 to 1.05 times the outer diameter of the stay cable. Its front part is conical, and the taper is the same as the inner cone angle of the fourth conical cavity. The rear part is cylindrical and is the same as the inner diameter of the fifth section cavity of the anchor inner cavity. Through the threaded engagement of the silicone rubber sealing ring 10 with the fifth section cavity, the silicone rubber sealing ring is compressed and expands and deforms to achieve efficient sealing of the stay cable end.

[0034] In addition to the above embodiments, the present invention also includes other implementation manners. All technical solutions formed by equivalent transformation or equivalent substitution shall fall within the protection scope of the claims of the present invention.

Claims

1. An anchor structure of a cable body, comprising an anchor cup and a nut, wherein the nut is screwed outside the anchor cup, and characterized in that: The interior of the anchor cup includes a coaxially distributed anchoring conical cavity, an intermediate transition cavity, a protective conical cavity and a sealing cavity. The anchoring conical cavity and the protective conical cavity are respectively located on the front and rear sides of the intermediate transition cavity, and the two cone directions are opposite. The cable body steel wire bundle passes through the sealing cavity, the protective conical cavity and the intermediate transition cavity in parallel from back to front, and then spreads out in a cone shape and is anchored in the anchoring conical cavity.

2. The anchor structure of the cable body according to claim 1, characterized in that: The axial length of the intermediate transition cavity is 50 mm to 100 mm. A positioning ring is arranged in the intermediate transition cavity, and the cable body steel wire bundle passes through the positioning ring.

3. The anchor structure of the cable body according to claim 1, characterized in that: The inner cone angle of the anchoring conical cavity is 5° to 10°, and the axial length is 300mm to 700mm. Anchoring fillers are cast in the cavity to fix the scattered steel wire bundles.

4. The anchor structure of the cable body according to claim 1, characterized in that: The inner cone angle of the protective conical cavity is 2° to 3°, the axial length is 300mm to 700mm, and filler is cast in the cavity to fix the cable body wire bundle. A positioning ring is arranged inside the protective conical cavity, and the cable body wire bundle passes through the positioning ring. The inner hole diameter of the positioning ring is 1.0-1.1 times the diameter of the cable body wire bundle.

5. The anchor structure of the cable body according to claim 4, characterized in that: The inner wall of the protective cone cavity is provided with an annular groove, and the positioning ring is arranged in the annular groove.

6. The anchor structure of the cable body according to claim 1, characterized in that: A sealing ring is arranged in the sealing cavity, and a sealing pressure ring is arranged on the rear side of the sealing ring. The sealing ring, the sealing pressure ring and the sealing cavity are screwed together. The sealing ring and the sealing pressure ring respectively have a center hole for the cable body to pass through. The inner diameter of the center hole of the sealing pressure ring is 1.01-1.05 times the diameter of the cable body, and the inner diameter of the center hole of the sealing ring is 0.95-1.05 times the diameter of the cable body.

7. The anchor structure of the cable body according to claim 6, characterized in that: The front end of the sealing ring is conical and screwed forward into the protective conical cavity. The rear end of the sealing pressure ring is exposed from the sealing cavity and presents a conical shape that gradually decreases from front to back. The outer periphery of the matching gap between the sealing pressure ring and the cable body is then wrapped with a shrink sleeve.

8. The anchor structure of the cable body according to claim 7, characterized in that: The shrink sleeve includes a heat shrink sleeve and a cold shrink sleeve.

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