Annular prestressed anchorage device for wind power mixed tower

Abstract

The invention provides a wind power mixed tower circumferential prestress anchorage device which comprises an anchor ring and an adjusting ring, the adjusting ring is arranged on the outer side of the anchor ring in a sleeving mode, and the adjusting ring is connected with the anchor ring through threads; an anchor hole is formed in the anchor ring, a clamping piece is installed in the anchor hole, a pressing plate is arranged above the clamping piece, and an elastic pad is arranged between the clamping piece and the pressing plate. The method has the beneficial effect that the problem of stress loss of the steel strand caused by retraction in the tensioning process is solved. The stress value of the steel strand can be effectively controlled, and the stress control requirement is met.

Description

Technical Field

[0001] This invention belongs to the field of wind power generation equipment, and in particular relates to a circumferential prestressed anchor for a wind power hybrid tower. Background Technology

[0002] Hybrid wind turbine towers (concrete lower structure, steel upper structure) are widely used in modern wind turbine generators due to their excellent load-bearing capacity and economic benefits. In the concrete tower section of the hybrid tower, prestressed steel strands are typically used for circumferential tensioning to improve its crack resistance and overall stiffness.

[0003] Currently, in the prestressed construction of wind turbine hybrid towers, the steel strands are commonly anchored using working anchor plates and working clamps. In practice, the initial tensioning and anchoring of individual prestressing tendons are performed first. Then, the anchor ring and the entire prestressing tendon undergo secondary tensioning. During this secondary tensioning, the anchor ring will move away from its bottom support plate by a certain distance (usually about 5 to 10 millimeters). When the jack returns to its original position, the anchor ring will retract back to the support plate under the prestress. This process causes the already tensioned steel strands to retract, resulting in a significant prestress loss. This stress loss caused by the anchor's own retraction directly affects the accuracy of prestressing establishment and the long-term safety of the structure, and is a problem that urgently needs to be solved in current engineering practice. Summary of the Invention

[0004] In view of this, in order to solve the stress loss problem caused by anchor retraction, the present invention aims to propose a circumferential prestressed anchor for wind power hybrid towers.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows: A circumferential prestressed anchor for a wind turbine hybrid tower includes an anchor ring and an adjusting ring. The adjusting ring is sleeved on the outside of the anchor ring and is connected to the anchor ring by a thread. The anchor ring has an anchor hole, a clamping plate is installed in the anchor hole, a pressure plate is provided above the clamping plate, and a spring washer is provided between the clamping plate and the pressure plate.

[0006] Furthermore, the pressure plate is fixed to the anchor ring by a first fastener.

[0007] Furthermore, the first fastener is a screw, and there are three of them.

[0008] Furthermore, the upper part of the anchor hole is an inverted frustum shape, and its diameter gradually decreases from top to bottom.

[0009] Furthermore, the adjusting ring is provided with a plurality of operating holes on its outer circumferential side for inserting tools to screw the adjusting ring.

[0010] Furthermore, a pad is provided at the bottom of the adjusting ring.

[0011] Furthermore, in the tensioned and locked state, the lower end face of the adjusting ring abuts against the upper end face of the pad to eliminate the gap between the lower end face of the anchor ring and the pad.

[0012] Furthermore, the length of the threaded connection section between the anchor ring and the adjusting ring is greater than or equal to the maximum distance that the lower end face of the anchor ring is expected to leave the upper end face of the pad during the tensioning process.

[0013] Furthermore, the spring pad is a butterfly spring, which is composed of two butterfly springs of the same specification stacked together with their convex surfaces facing each other or their concave surfaces facing each other.

[0014] Furthermore, the anchor is used to anchor the steel strand. The unsheathed end of the steel strand passes through the pad and the anchor hole in sequence, is held by the clamping plate, and finally passes through the spring pad and extends out from the top of the pressure plate.

[0015] The stress transfer process of this invention is as follows: the screw tightens the pressure plate, transferring the force to the spring washer; the spring washer adjusts itself through its elasticity, then tightens the clamping plate; the clamping plate, through its own anchoring characteristics, grips the unsheathed section of the steel strand, firmly locking the steel strand; the force on the clamping plate is transferred to the anchor hole of the anchor ring, the force in the anchor hole is transferred to the anchor ring, the force in the anchor ring is transferred to the adjusting ring, the force in the adjusting ring is transferred to the pad, and finally, the force is transferred to the concrete structure through the pad. The force transfer sequence is: steel strand—clamping plate—anchor ring—adjusting ring—pad—concrete structure. This anchor structure has been optimized to reduce the amount of retraction during tensioning and reduce stress loss.

[0016] The advantages and positive effects of this invention are: it solves the problem of stress loss in steel strands caused by shrinkage during tensioning. It can effectively control the stress value of the steel strands, meeting stress control requirements. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a top view of the present invention.

[0019] In the diagram: 1. Anchor ring; 2. Adjusting ring; 3. Clamping plate; 4. Pressure plate; 5. First fastener; 6. Spring washer; 7. Pad plate; 8. Steel strand. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In the absence of conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0021] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0022] Secondly, the present invention will be described in detail with reference to the schematic diagrams. When describing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the structure of the device will be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, in actual manufacturing, the three-dimensional spatial dimensions of length, width, and height should be included.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] like Figure 1 and Figure 2 As shown, the present invention provides a circumferential prestressed anchor for a wind power hybrid tower, comprising an anchor ring 1, an adjusting ring 2, a clamping plate 3, a pressure plate 4, a first fastener 5, a spring washer 6, a pad 7, and a steel strand 8 to be anchored.

[0026] Anchor ring 1 is the central load-bearing component of the anchor. It has external threads machined on its outer center and a through anchor hole in its center. The upper part of the anchor hole is designed as an inverted frustum (cone), with the diameter gradually narrowing from top to bottom.

[0027] The adjusting ring 2 is an annular component with an internal thread in its inner hole that matches the external thread of the anchor ring 1. The adjusting ring 2 is fitted onto the outer side of the middle portion of the anchor ring 1 via a threaded joint. Multiple operating holes are evenly spaced circumferentially on the outer cylindrical surface of the adjusting ring 2 for inserting tools such as wrenches to apply torque and tighten the adjusting ring 2, thereby adjusting its axial position on the anchor ring 1. The bottom end face of the adjusting ring 2 is a flat, pressure-bearing surface.

[0028] The pad 7 is located at the bottom of the adjusting ring 2 and is usually fixed to the concrete structure surface by pre-embedding or post-installation. The pad 7 has a hole in the center for the steel strand 8 to pass through.

[0029] The wedge 3 is usually a set of two or three wedge-shaped pieces. Its outer surface is a conical surface that matches the conical surface inside the anchor hole of the anchor ring 1, and its inner surface is engraved with teeth to engage the steel strand 8. The wedge 3 is installed inside the conical anchor hole of the anchor ring 1.

[0030] The pressure plate 4 is a disc-shaped piece with a central opening, covering the clamping plate 3. A spring pad 6 is placed between the clamping plate 3 and the pressure plate 4. In this embodiment, the spring pad 6 is a butterfly spring assembly composed of two identical butterfly spring sheets stacked together with their convex or concave surfaces facing each other. The pressure plate 4 is fastened to the top of the anchor ring 1 by three circumferentially distributed first fasteners 5 (e.g., screws). When the first fasteners 5 are tightened, the pressure plate 4 presses down on the spring pad 6, causing the spring pad 6 to elastically deform and transmit pressure to the clamping plate 3, causing it to wedge tightly within the cone surface of the anchor hole, thereby initially gripping the passing steel strand 8.

[0031] The unsheathed end (i.e. the tensioning end) of the steel strand 8 is threaded in the following order: first through the center hole of the pad 7, then through the anchor hole of the anchor ring 1, then through the center of the clamping piece 3 already placed in the hole, then through the center hole of the spring pad 6, and finally through the center hole of the pressure plate 4 to extend upwards for connection with the tensioning jack.

[0032] The working process of this invention is as follows: In prestressed construction, after the initial tensioning and preliminary anchoring of each individual steel strand 8, overall secondary tensioning is performed. During tensioning, jacks are applied to the extended end of the steel strand 8, and the tension is transmitted through the steel strand 8 to the wedge 3. The wedge 3 weaves tighter and tighter within the conical hole, transferring the force to the anchor ring 1. The anchor ring 1, under stress, tends to move upwards, resulting in a gap between its lower end face and the upper end face of the pad 7 (this gap is typically 5 to 10 mm, representing the maximum expected retraction distance). At this point, the tension is maintained (holding load).

[0033] Under load, the operator uses a tool (such as a wrench) to insert into the operating hole of the adjusting ring 2 and screws the adjusting ring 2 downward along the thread of the anchor ring 1 until the lower end face of the adjusting ring 2 is tightly abutted against the upper end face of the pad 7. This operation eliminates the original gap between the anchor ring 1 and the pad 7 and locks the adjusting ring 2 in this relative position.

[0034] Subsequently, the jack slowly returns oil to release pressure and tension. In traditional anchorages, the anchor ring 1 would retract to the pad 7 at this stage. However, in this invention, since the adjusting ring 2 has descended and is tightly against the pad 7, it forms a robust mechanical stop, effectively preventing the anchor ring 1 from retracting downwards. Therefore, the anchor ring 1, the wedge 3, and the clamped steel strand 8 are all locked at the tensioned position, and the steel strand 8 cannot retract, thus achieving "retraction-free" tensioning and completely eliminating the resulting prestress loss.

[0035] The stress transfer process of this invention is as follows: the screw tightens the pressure plate, transferring the force to the elastic washer; the elastic washer adjusts itself through its elasticity, then tightens the clamping plate; the clamping plate, through its own anchoring characteristics, grips the unsheathed section of the steel strand, firmly locking the steel strand; the force on the clamping plate is transferred to the anchor hole of the anchor ring, the force on the anchor hole is transferred to the anchor ring, the force on the anchor ring is transferred to the adjusting ring, the force on the adjusting ring is transferred to the pad, and finally, the force is transferred to the concrete foundation structure through the pad. The force transfer sequence is: steel strand—clamping plate—anchor ring—adjusting ring (transferred through the threaded pair)—pad—concrete structure. This anchor structure is optimized to reduce the amount of retraction during tensioning and reduce stress loss. Throughout the process, the elastic washer 6 continuously provides elastic clamping force, ensuring the reliability of the clamping plate 3 anchorage and absorbing some vibration energy, improving the stability of the anchor under dynamic load conditions.

[0036] A spring pad is essentially two disc springs stacked together, with either their convex or concave surfaces facing each other. A pressure plate compresses the springs, causing them to deform and thus securing the clamping plates. The spring's elastic deformation provides upward displacement for the steel strand and anchorage, ensuring the application of tension. The spring pad also provides cushioning, improving the anchorage's vibration damping performance and preventing the clamping plates from loosening in high-vibration anchoring systems.

[0037] The effective length of the threaded engagement between the anchor ring 1 and the adjusting ring 2 is designed to be greater than or equal to the maximum gap distance that may occur during tensioning (i.e., the maximum distance that the lower end face of the anchor ring 1 is expected to leave the upper end face of the pad 7). This design ensures that the adjusting ring 2 always has sufficient axial adjustment stroke to fully compensate for and lock the gap, thereby ensuring that the locking function can be reliably achieved under all expected operating conditions.

[0038] This solution addresses the stress loss in the steel strands caused by shrinkage during tensioning. It effectively controls the stress value of the steel strands, meeting stress control requirements.

[0039] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A circumferential prestressed anchor for a wind turbine hybrid tower, characterized in that: It includes an anchor ring (1) and an adjusting ring (2), wherein the adjusting ring (2) is sleeved on the outside of the anchor ring (1), and the adjusting ring (2) is connected to the anchor ring (1) by a thread; The anchor ring (1) has an anchor hole, a clamping piece (3) is installed in the anchor hole, a pressure plate (4) is provided above the clamping piece (3), and a spring pad (6) is provided between the clamping piece (3) and the pressure plate (4).

2. The circumferential prestressed anchorage for a wind turbine hybrid tower according to claim 1, characterized in that: The pressure plate (4) is fixed to the anchor ring (1) by the first fastener (5).

3. The circumferential prestressed anchorage for a wind turbine hybrid tower according to claim 2, characterized in that: The first fastener (5) is a screw, and there are three of them.

4. The circumferential prestressed anchorage for a wind turbine hybrid tower according to claim 1, characterized in that: The upper part of the anchor hole is an inverted frustum shape, and its diameter gradually decreases from top to bottom.

5. The circumferential prestressed anchorage for a wind turbine hybrid tower according to claim 1, characterized in that: The adjusting ring (2) has multiple operating holes circumferentially arranged on its outer side.

6. The circumferential prestressed anchorage for a wind turbine hybrid tower according to claim 1, characterized in that: A pad (7) is provided at the bottom of the adjusting ring (2).

7. The circumferential prestressed anchorage for a wind turbine hybrid tower according to claim 6, characterized in that: In the tensioned and locked state, the lower end face of the adjusting ring (2) abuts against the upper end face of the pad (7).

8. The circumferential prestressed anchorage for a wind power hybrid tower according to claim 6, characterized in that: The length of the threaded connection between the anchor ring (1) and the adjusting ring (2) is greater than or equal to the maximum distance that the lower end face of the anchor ring (1) is expected to leave the upper end face of the pad (7) during the tensioning process.

9. The circumferential prestressed anchorage for a wind turbine hybrid tower according to claim 1, characterized in that: The spring pad (6) is a butterfly spring, which is composed of two butterfly springs of the same specification stacked together with their convex surfaces facing each other or their concave surfaces facing each other.

10. The circumferential prestressed anchorage for a wind power hybrid tower according to claim 6, characterized in that: The anchor is used to anchor the steel strand (8). The unsheathed end of the steel strand (8) passes through the pad (7) and the anchor hole in sequence, and is held by the clamp (3). Finally, it passes through the spring pad (6) and extends out from the top of the pressure plate (4).

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