Hybrid wind power tower anchoring conversion node and construction method thereof

Abstract

The application relates to the technical field of structural engineering, in particular to a mixed wind power tower anchoring conversion node and a construction method thereof. The mixed wind power tower anchoring conversion node comprises a concrete tower cylinder, a lower steel tower cylinder arranged at the top of the concrete tower cylinder, and a conversion section arranged at the top of the concrete tower cylinder. A prestressed anchoring assembly is arranged in the conversion section and comprises an anchor fixed at the outer side of the bottom of the lower steel tower cylinder and at the inner wall of the conversion section, and a connecting piece fixed at the inner side of the bottom of the lower steel tower cylinder. The anchor is designed as a J-shaped structure, the upper end of the anchor is fixed to the lower steel tower cylinder near the outer side of the cylinder wall, and the lower end of the anchor is anchored into the inner side of the cylinder wall of the conversion section through an arc path, so that force is directly transmitted from the outside to the inner wall along the path of the anchor itself without the need of a lower anchor plate, thereby eliminating stress concentration in the area of the lower anchor plate.

Description

Technical Field

[0001] This invention relates to the field of structural engineering technology, and in particular to an anchorage conversion node for a hybrid wind power generation tower and its construction method. Background Technology

[0002] Hybrid wind turbine towers have become the mainstream structural form for tall towers in low wind speed areas due to their superior structural rigidity and economy. They consist of a steel upper tower and a precast concrete lower tower, but the two differ significantly in mechanical properties such as elastic modulus and strength. To achieve effective load transfer and coordinated stress distribution, a reasonably stressed and structurally reliable transition node must be installed at the interface between the two. This node is a key component determining the overall structural safety and durability.

[0003] Currently, the conversion node structure widely used in large units in the industry adopts a straight anchor bolt connection. The upper end of the anchor bolt is anchored to the bottom flange of the steel tower, and the lower end transmits the anchoring force through the lower anchor plate embedded in the concrete.

[0004] However, this method of force transmission will cause the anchor bolt tension to be too concentrated in a local area of ​​the lower anchor plate, resulting in excessively high peak stress in the surrounding concrete and forming a significant stress concentration zone. At the same time, the lower anchor plate of this anchoring method has dense reinforcement and a narrow space, making concrete pouring and vibration difficult and easily leading to quality problems such as non-compactness and voids.

[0005] Furthermore, under extreme loads, the flange contact surface of this anchoring method is prone to opening, allowing rainwater to seep in along the anchor bolt holes. Combined with the long-term micro-vibrations during wind turbine operation, this accelerates the wear and deterioration of the concrete around the anchor plate, creating a risk of anchoring failure. In addition, the lower anchor plate divides the transition section concrete into inner and outer parts. During precast curing, the outer cylinder wall often develops longitudinal through cracks due to shrinkage constraints. Although carbon fiber reinforcement is commonly used in engineering, this method only covers surface cracks and cannot fundamentally eliminate the root causes of stress concentration and insufficient concrete compaction. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is: the core problems of stress concentration in the lower anchor plate, easy shrinkage cracks in precast concrete, and insufficient compaction of concrete in the existing technology.

[0007] The above-mentioned technical problems are solved by the following technical solution: The present invention proposes an anchoring conversion node for a hybrid wind power generation tower, which includes a concrete tower, a lower steel tower set on top of the concrete tower, and a conversion section set on top of the concrete tower.

[0008] The prestressed anchoring assembly is installed inside the transition section and includes an anchor that is anchored at the top to the outer side of the bottom of the lower steel tower and at the bottom to the inner wall of the transition section, as well as a connector that is anchored at the top to the inner side of the bottom of the lower steel tower. The bottom of the anchor penetrates the transition section and is anchored to the inner wall of one side of the transition section; The anchors and connectors apply opposing tension forces to the lower steel tower from different directions.

[0009] In a preferred embodiment of the anchoring conversion node of the hybrid wind power generation tower of the present invention: the anchor includes a straight section, a curved section disposed at the bottom of the straight section, a fixed end disposed at the top of the straight section, and a tensioning end disposed on the side of the curved section away from the straight section.

[0010] In a preferred embodiment of the anchoring transition node of the hybrid wind power generation tower of the present invention: the transition section includes an upper section disposed at the top of the concrete tower, an inclined section connected to the bottom of the upper section, and a lower section connected to the bottom of the inclined section; The concrete tower has a cavity inside, and the tensioning end extends through the inclined section into the cavity.

[0011] In a preferred embodiment of the anchoring conversion node of the hybrid wind power generation tower of the present invention: an anchoring lock is provided on one side of the tensioning end, and the tensioning end is fixed to the side of the inclined section near the cavity by the anchoring lock.

[0012] In a preferred embodiment of the anchoring conversion node of the hybrid wind power generation tower of the present invention: an external line hole is provided at the bottom of the lower steel tower, and the fixed end passes through the external line hole and is fixed to the bottom of the lower steel tower on the side away from the cavity.

[0013] In a preferred embodiment of the anchoring conversion node of the hybrid wind power generation tower of the present invention: a grouting channel is provided on one side of the concrete tower, and an outer protective pipe is provided on the outer wall of the straight section and the curved section of the anchor. The outer protective pipe penetrates the inner wall of the upper section and the middle section, and the grouting channel is connected to the outer protective pipe.

[0014] In a preferred embodiment of the anchoring conversion node of the hybrid wind power generation tower of the present invention: the connector includes a steel strand and a steel strand tensioning end disposed at the top of the steel strand.

[0015] In a preferred embodiment of the anchoring conversion node of the hybrid wind power generation tower of the present invention: an inner wire hole is also provided at the bottom of the lower steel tower, and the tensioning end of the steel strand passes through the inner wire hole and is fixed to the bottom of the lower steel tower near the cavity.

[0016] In a preferred embodiment of the anchoring conversion node of the hybrid wind power generation tower of the present invention: an upper steel tower is provided at the top of the lower steel tower.

[0017] This invention proposes a construction method for the anchorage conversion node of a hybrid wind power generation tower, which includes the following steps: The outer protective pipe is fitted to the anchor and pre-embedded in the transition section together with the connector. At the same time, a grouting channel is reserved in the transition section to connect with the outer protective pipe. Place the transition section on the ground and position the tooling. Lift the lower steel tower and splice it with the transition section. Pass the connector through the inner hole of the tower and anchor its upper end to the bottom of the lower steel tower. After all components are installed, perform the initial tensioning of the anchors under ground conditions. When using a bonded prestressed scheme, after tensioning is completed, grouting is carried out into the transition section through the grouting channel to fill the outer casing with grout. After the grout hardens, the grouting channel is sealed. When using an unbonded prestressing scheme, there is no need to grout the inside of the outer casing after tensioning; The transition section containing the lower steel tower is lifted and installed on top of the concrete tower. The bottom end of the connector is anchored to the foundation at the bottom of the tower, and the connector is tensioned. If an unbonded prestressing scheme is adopted, the anchors need to be tensioned again after the connection is tensioned. The anchoring point at the top of the anchor should be sealed with anti-corrosion material to prevent rainwater from seeping in.

[0018] The beneficial effects of this invention are as follows: by designing the anchor as a J-shape, with its upper end fixed to the outer side of the lower steel tower near the outer wall and its lower end inserted into the inner wall of the transition section via an arc path, the force is directly transmitted from the outside to the inner wall along the anchor's own path without the need for a lower anchor plate, thereby eliminating stress concentration in the lower anchor plate area and leaving space for concrete pouring, avoiding shrinkage cracks caused by anchor plate separation; in conjunction with the connector, counter-tension is applied to the inner side of the lower steel tower near the inner wall, so that the forces on both sides of the lower steel tower are balanced and the contact surfaces are kept pressed, preventing flange opening and rainwater infiltration. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0020] Figure 1 A schematic diagram of the overall structure of the anchoring conversion node of a hybrid wind power generation tower is shown.

[0021] Figure 2A schematic diagram of the conversion connection component is shown.

[0022] Figure 3 A schematic diagram of the prestressed anchoring assembly is shown.

[0023] Figure 4 A top view of the concrete tower is shown.

[0024] Figure 5 A schematic diagram of the anchor is shown. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0026] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0027] Reference Figure 1 This embodiment provides an anchoring conversion node for a hybrid wind power generation tower, including: The conversion connection assembly 1 includes a concrete tower 11, a lower steel tower 12 disposed on top of the concrete tower 11, and a conversion section 13 disposed on top of the concrete tower 11. The concrete tower 11 is the lower load-bearing structure, and its interior is hollow to form a cavity 111, in which construction personnel can perform tensioning and maintenance operations.

[0028] The lower steel tower 12 is the connection structure between the upper steel tower 14 and the concrete tower 11. An L-shaped flange is provided at the top of the lower steel tower 12 and is connected to the upper steel tower 14 by bolts. A T-shaped flange is provided at the bottom and is connected to the concrete tower 11 by bolts. The side of the T-shaped flange near the cavity 111 forms an anchoring surface, and the side away from the cavity 111 forms another anchoring surface.

[0029] The transition section 13 is a precast concrete component located at the top of the inner wall of the concrete tower 11. Its overall thickness varies, with the side closer to the lower steel tower 12 being thicker and the side farther from the lower steel tower 12 being thinner. This layer-by-layer thickening design can effectively withstand the pressure generated when the anchor 21 and connector 22 are tensioned.

[0030] The lower steel tower 12 is topped with an upper steel tower 14, wherein the upper steel tower 14 is fixedly connected to the L-shaped flange at the top of the lower steel tower 12 via its bottom flange.

[0031] The prestressed anchoring assembly 2 is installed inside the transition section 13 and includes an anchor 21 that is anchored at the top to the outer side of the bottom of the lower steel tower 12 and at the bottom to the inner wall of the transition section 13, and a connector 22 that is anchored at the top to the inner side of the bottom of the lower steel tower 12. The bottom of the anchor 21 penetrates the transition section 13 and is anchored to the inner wall of one side of the transition section 13. It should be noted that the anchor 21 is generally J-shaped. Its side away from the lower steel tower 12 penetrates the wall of the transition section 13 and is anchored to the wall of the transition section 13. After the anchor 21 is fixed to the transition section 13, it can form a special force transmission channel through its shape. When the transition section 13 and the lower steel tower 12 are subjected to force, the force will be transmitted vertically downward through the upper end of the anchor 21, and then transmitted to the wall of the transition section 13 through an arc. This increases the force transmission path and the effect of transmitting force in different directions, thereby avoiding the force from being too concentrated and directed to a certain point.

[0032] Meanwhile, since one side of the anchor 21 penetrates the transition section 13 into the cavity 111, there is no need to go outside the tower to perform tensioning and locking operations, thus ensuring stability during operation.

[0033] It should also be noted that the connector 22 is arranged on the side of the cylinder wall near the cavity 111. It is located on the side of the lower steel tower cylinder 12 near the cavity 111. The lower part of the connector 22 extends through the transition section 13 into the cavity 111.

[0034] Anchor 21 and connector 22 apply opposing tension forces to the lower steel tower 12 from different directions. Anchor 21 is J-shaped, and its shape ensures that it can hold the lower steel tower 12 with sufficient force when the tower is under stress. It works with connector 22 to further fix the lower steel tower 12 to the concrete tower 11. Anchor 21 and connector 22 clamp the lower steel tower 12 from both sides, so that the lower steel tower 12 and the lower transition section 13 always remain tightly fitted and will not be lifted by wind load.

[0035] As an alternative embodiment, the effect of the prestressed anchoring component 2 is specifically illustrated.

[0036] The transition section 13 includes an upper section 131 located at the top of the concrete tower 11, an inclined section 133 connected to the bottom of the upper section 131, and a lower section 132 connected to the bottom of the inclined section 133. A cavity 111 is provided inside the concrete tower 11, and the tensioning end 214 extends through the inclined section 133 into the cavity 111. The upper section 131 is an annular wall section of equal thickness located directly below the lower steel tower 12. Its function is to bear the huge preload generated when the connector 22 and anchor 21 are tensioned. Therefore, the wall thickness of the upper section 131 needs to meet the compressive strength requirements, and there are sufficient circumferential and longitudinal steel bars inside to disperse the preload.

[0037] The inclined section 133 is connected below the upper section 131. Its cross-section gradually transitions from the wall thickness of the upper section 131 to the wall thickness of the concrete tower 11, forming a sloping surface that is narrow at the top and wide at the bottom when viewed from the outside. The angle and length of the inclined section 133 are determined according to the bending angle and radius of the curved section 212 of the anchor 21. The purpose is to allow the curved section 212 to naturally transition along the slope of the inclined section 133 when passing through the cylinder wall, so as to avoid generating additional bending moment at the wall penetration point.

[0038] The lower section 132 is located below the inclined section 133. Its wall thickness is the same as that of the concrete tower 11, which plays a role in the smooth transition from the transition section 13 to the concrete tower 11 and avoids stress concentration caused by sudden changes in cross-section.

[0039] The anchor 21 includes a straight section 211, a curved section 212 located at the bottom of the straight section 211, a fixed end 213 located at the top of the straight section 211, and a tensioning end 214 located on the side of the curved section 212 away from the straight section 211. The straight section 211 is the straight section at the top of the anchor 21. It passes vertically downward from the surface of the T-shaped flange at the bottom of the lower steel tower 12 through the outer hole 23 of the cylinder, so that the transition section 13 enters the interior of the upper section 131.

[0040] The anchor 21 also includes an anchor straight section 211 disposed at the top of the curved section 212, a fixed end 213 disposed at the top of the anchor straight section 211, and a tensioning end 214 disposed on the side of the curved section 212 away from the anchor straight section 211. The anchor straight section 211 is a straight section at the top of the anchor 21. It passes vertically downward from the surface of the bottom T-shaped flange of the lower steel tower 12 through the outer hole 23 of the cylinder, so that the transition section 13 enters the interior of the upper section 131.

[0041] The outer wall of the anchor section 211 is fitted with an outer protective tube 215. The function of the outer protective tube 215 is to separate the anchor 21 from the surrounding concrete, so that the anchor 21 can freely expand and contract inside the outer protective tube 215 without being directly wrapped by the concrete, thereby ensuring that the anchor 21 can smoothly generate prestress deformation during tensioning.

[0042] The curved section 212 is the key arc-shaped section of the anchor 21 that transitions from the upper straight section to the lower anchoring position. Its function is to guide the force transmission path of the anchor 21 from the outside of the cylinder to the inside of the cylinder. Specifically, the curved section 212 bends inward from the bottom end of the straight section 211, passes through the cylinder wall of the transition section 13, and reaches the inner side of the cylinder wall. This allows the upper end of the anchor 21 to be anchored on the bottom T-shaped flange of the lower steel tower cylinder 12, while the lower end is anchored on the inner side of the cylinder wall of the transition section 13.

[0043] The J-shaped structure of anchor 21 allows its tensioning operation to be completed inside the tower, eliminating the need for operation at high altitudes or outside the tower, thus greatly reducing construction difficulty and safety risks.

[0044] The fixed end 213 is located at the top of the anchor 21 and is the locking position of the anchor 21 after tensioning. After the fixed end 213 passes through the outer line hole 23 opened on the bottom T-shaped flange of the lower steel tower 12, it is locked and fixed to the upper surface of the bottom T-shaped flange of the lower steel tower 12 by the anchor. The anchor is stuck above the outer line hole 23, thereby locking the prestress generated by tensioning onto the anchor 21.

[0045] The tensioning end 214 is located at the bottom of the curved section 212 and is where the jack applies tension during the tensioning operation. During tensioning, the jack clamps and stretches the tail of the tensioning end 214 outward, causing the anchor 21 to elastically elongate and thus establish prestress. After tensioning is completed, the tensioning end 214 is fixed to the inside of the inclined section 133 of the transition section 13 by the anchoring lock 25 to ensure that the prestress will not dissipate due to the retraction of the anchor 21.

[0046] An anchoring device 25 is provided on one side of the tensioning end 214. The tensioning end 214 is fixed to the side of the inclined section 133 near the cavity 111 by the anchoring device 25. The tensioning end 214 is provided with threads. The anchoring device 25 consists of a backing plate and a nut. The backing plate abuts against the inner wall of the inclined section 133. Then, by tightening the nut, the backing plate is made to fit tightly against the inner wall of the inclined section 133, thereby fixing the tensioning end 214 to the inner wall of the inclined section 133. This allows the prestress generated by the anchor 21 after tensioning to be permanently maintained.

[0047] The bottom of the lower steel tower 12 is provided with an external cable hole 23. The fixed end 213 passes through the external cable hole 23 and is fixed to the bottom of the lower steel tower 12 on the side away from the cavity 111. The external cable hole 23 is a through hole that runs from the upper surface of the lower steel tower 12 to the lower surface. Its position corresponds to the position of the anchor 21. The diameter of the external cable hole 23 needs to be slightly larger than the outer diameter of the anchor section 211 so that the anchor 21 can be smoothly inserted. The external cable holes 23 are evenly distributed along the outer circumference of the lower steel tower 12. The number and spacing are determined according to the arrangement of the anchor 21.

[0048] A grouting channel 24 is provided on one side of the concrete tower 11. An outer protective pipe 215 is fitted over the outer walls of the straight section 211 and the curved section 212. The outer protective pipe 215 penetrates the inner walls of the upper section 131 and the middle section 132. The grouting channel 24 is connected to the outer protective pipe 215. The function of the outer protective pipe 215 is to isolate the anchor 21 from the surrounding concrete. It is pre-embedded in the formwork before the concrete of the upper section 131 is poured. After the concrete hardens, the outer protective pipe 215 forms a ring-shaped hollow pipe, and the anchor 21 passes through the inside of the pipe. The grouting channel 24 is a pipe that runs from the outer wall of the concrete tower 11 to the inside of the outer protective pipe 215. It is usually made of steel pipe, with one end connected to the internal space of the outer protective pipe 215 and the other end exposed on the outer surface of the concrete tower 11 for easy connection of the grouting equipment.

[0049] For the bonded solution, after the anchor 21 is tensioned, cement grout is injected into the outer casing 215 through the grouting channel 24. The cement grout fills the gap between the outer casing 215 and the anchor 21. After the grout solidifies, the anchor 21 is bonded to the concrete as a whole, thereby improving the durability and fatigue resistance of the anchor.

[0050] For the unbonded scheme, no grout is injected inside the outer casing 215, and the anchor 21 can freely expand and contract inside the casing. The prestress is entirely borne by the anchor and the anchoring lock 25.

[0051] The connector 22 includes a steel strand 221 and a steel strand tensioning end 222 disposed on the top of the steel strand 221. The lower end of the steel strand 221 is anchored in the foundation at the bottom of the tower, and the upper end is anchored to the inner side of the lower steel tower 12 through the steel strand tensioning end 222.

[0052] The steel strand 221 is encased in a PVC sleeve. The purpose of the PVC sleeve is to separate the steel strand 221 from the concrete, so that the steel strand 221 can expand and contract freely during tensioning without being encased in concrete.

[0053] The bottom of the lower steel tower 12 is also provided with an inner wire hole 26. The tensioning end 222 of the steel strand passes through the inner wire hole 26 and is fixed to the bottom of the lower steel tower 12 on the side near the cavity 111. The inner wire hole 26 is located in the inner area of ​​the lower steel tower 12 and corresponds to the outer wire hole 23.

[0054] The steel strand 221 passes through the inner hole 26 of the cylinder from top to bottom and enters the pre-embedded channel inside the transition section 13. It continues to pass through the concrete tower cylinder 11 to reach the bottom of the foundation. During tensioning, the jack applies tension to the tensioning end 222 of the steel strand from above the lower steel tower cylinder 12. The tension is transmitted downward through the steel strand 221 to the anchor point at the bottom of the foundation, thereby establishing prestress in the steel strand 221. After tensioning is completed, the tensioning end 222 of the steel strand is locked to the inner side of the upper surface of the lower steel tower cylinder 12 by the anchor.

[0055] In summary, during the tensioning operation, the anchor 21 is first tensioned during the ground assembly stage. A jack is placed on the inner wall of the inclined section 133 of the transition section 13, applying tension to the tensioning end 214. This tension is transmitted upwards along the curved section 212 to the straight section 211, and then applied to the outer side of the upper surface of the lower steel tower 12 through the anchor at the fixed end 213. This results in a downward tension on the outer side of the lower steel tower 12. Simultaneously, the connector 22 also applies tension to the lower steel tower 12 from the inside. When the wind turbine is running, the wind load is transferred from the upper steel tower 14 to the lower steel tower 12, and then to the transition section 13 through the prestressed clamping force of the anchor 21 and the connector 22. Since the anchor 21 pulls from the outside and the connector 22 pulls from the inside, the lower steel tower 12 is like being clamped by two hands from both sides. This opposing tension ensures that the lower steel tower 12 and the concrete surface below always remain in close contact, which greatly improves the overall stiffness and torsional shear bearing capacity of the joint.

[0056] It should also be noted that during the tensioning of anchor 21, since the tensioning end 214 is anchored to the inner wall of the inclined section 133 of the transition section 13, the tension force will be transmitted to the concrete of the inclined section 133 through the anchor lock 25, causing the inclined section 133 to bear a large local pressure. Therefore, the inner wall of the inclined section 133 is usually thickened, or a steel pad is pre-embedded in the inner wall to distribute the contact pressure between the jack and the anchor lock 25 and prevent the concrete from being crushed. At the same time, during the tensioning process, each anchor 21 needs to be tensioned symmetrically and evenly to avoid the lower steel tower 12 from tilting due to uneven force.

[0057] It is important to note that during long-term operation, the anchor lock 25 may gradually loosen due to continuous micro-vibrations of the tower, leading to prestress loss. To address this, an elastic washer can be installed between the anchor lock 25 and the tensioning end 214. The deformation of the elastic washer can compensate for minor loosening, thereby reducing the risk of prestress loss. Additionally, during the pre-bending process of the outer protective pipe 215, if the bending radius is too small, the pipe wall may wrinkle or flatten, affecting subsequent threading and grouting operations. Therefore, the bending radius of the outer protective pipe 215 needs to be determined based on the pipe diameter and wall thickness. After bending, the pipe cross-section should remain approximately circular to ensure that the anchor 21 can be smoothly inserted into the pipe and freely expand and contract.

[0058] This embodiment provides a construction method for the anchorage conversion node of a hybrid wind power generation tower, including the following steps: An outer protective pipe 215 is fitted onto the anchor 21 and pre-embedded together with the connector 22 into the transition section 13. At the same time, a grouting channel 24 is reserved in the transition section 13 to connect with the outer protective pipe 215. Place the transition section 13 on the ground and position the tooling. Lift the lower steel tower 12 and splice it with the transition section 13. Pass the connector 22 through the inner hole 26 of the cylinder and anchor its upper end to the bottom of the lower steel tower 12. After all components are installed, perform the initial tensioning of the anchor 21 under ground conditions. When using a bonded prestressed scheme, after tensioning is completed, grouting is carried out into the transition section 13 through the grouting channel 24, so that the outer protective pipe 215 is filled with grout. After the grout hardens, the grouting channel 24 is sealed. When using the unbonded prestressing scheme, there is no need to grout the inside of the outer protective tube 215 after tensioning is completed; The transition section 13, which is equipped with the lower steel tower 12, is lifted and installed on the top of the concrete tower 11. The bottom end of the connector 22 is anchored to the bottom foundation of the tower, and the connector 22 is tensioned. If an unbonded prestressing scheme is adopted, the anchor 21 needs to be tensioned a second time after the tensioning of the connector 22 is completed. The anchoring point at the upper end of anchor 21 shall be sealed with anti-corrosion material to prevent rainwater from seeping in. Inside the factory, the outer protective sleeve 215 is fitted onto the anchor 21, and it is pre-embedded in the transition section 13 along with the sleeve of the connector 22. Special tooling is required during pre-embedding to ensure positional accuracy, guaranteeing that the angle and position of the curved section of the anchor 21 meet design requirements. Simultaneously, an L-shaped flange and matching high-strength bolts and nuts are welded to the top of the lower steel tower 12. The L-shaped flange is used for subsequent ground assembly and overall hoisting. A specially designed high-neck flange is installed at the bottom of the lower steel tower 12, which needs to be welded to the lower steel tower 12 at the steel structure processing plant and then subjected to anti-corrosion treatment.

[0059] The transition section 13 is transported to the site and placed on the ground with the fixtures in place. The lower steel tower 12 is lifted and assembled with the transition section 13. Then, the connector 22 is passed through the pre-set inner hole 26 on the bottom flange of the lower steel tower 12 and its upper end is anchored to the pre-set anchoring position of the transition section 13. After all components are installed in place, the prestressed bolts are initially tensioned under ground conditions. After the entire structure is hoisted into place, apply epoxy resin adhesive or mortar to the horizontal joint at the top of the concrete tower 11 for leveling. Then, hoist the assembled transfer section 13 of the concrete tower 11 to the top of the concrete tower 11. During the hoisting process, it is necessary to keep the structure stable and avoid collisions with the connecting surface at the top of the concrete tower 11. After positioning, it is necessary to check whether the gap between the lower steel tower 12 and the top surface of the concrete tower 11 is uniform to ensure that the two can fit well together.

[0060] After anchoring the bottom end of the connector 22 to the concrete tower 11, the connector 22 is tensioned. After tensioning, the anchorage of the anchor 21 is sealed with anti-corrosion material to prevent rainwater from seeping in. At this point, the construction of the entire conversion node is completed.

[0061] As an alternative embodiment, another method for constructing anchorage transition nodes is provided in the case of an unbonded solution.

[0062] When using the unbonded prestressing scheme, after tensioning, there is no need to grout the inner casing 215. The connector 22 is tensioned directly. After the connector 22 is tensioned, the anchor 21 is tensioned again. Epoxy resin is applied to the base of the concrete tower 11 for leveling. The concrete tower 11 is then hoisted to the base for installation.

[0063] For the unbonded solution, there is no need to grout the outer casing 215. At this time, the anchor 21 can freely expand and contract inside the pipe, and the prestress is entirely borne by the anchor and the anchor lock 25. Therefore, there is no need to reserve the grouting channel 24. It should be noted that if an unbonded solution is adopted, after tensioning the connector 22, due to the elastic compression of the concrete, the previously tensioned anchor 21 will lose some prestress. Therefore, the prestressed bent bolts need to be tensioned a second time to make up for the prestress loss caused by the concrete compression until the design prestress value is reached. After tensioning is completed, the anchorage at the upper end of the prestressed bent bolts is sealed with anti-corrosion treatment to prevent rainwater from seeping in. At this point, the construction of the entire transition node is completed.

[0064] It should also be noted that before the second tensioning, the condition of the anchoring devices after the first tensioning must be checked to ensure that they are not loose or displaced. During the second tensioning, the jacks are clamped again at the tensioning end to apply tension, and the prestress is replenished to the design value before the anchoring devices are tightened again.

[0065] Because the subsequent hoisting and tensioning of the connector 22 will cause elastic compression of the concrete, resulting in the loss of prestress in the anchor bolt 25, the initial tension force of the anchor bolt 25 must be included in this prestress reserve value. This value needs to be calculated and determined based on the concrete compression modulus and the design axial force of the steel strands in the cylinder to ensure that the final effective prestress meets the design requirements.

[0066] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. An anchoring conversion node for a hybrid wind power generation tower, characterized in that: include, The conversion connection assembly (1) includes a concrete tower (11), a lower steel tower (12) disposed on top of the concrete tower (11), and a conversion section (13) disposed on top of the concrete tower (11). The prestressed anchoring assembly (2) is located inside the transition section (13) and includes an anchor (21) with its top anchored to the outer side of the bottom of the lower steel tower (12) and its bottom anchored to the inner wall of the transition section (13), and a connector (22) with its top anchored to the inner side of the bottom of the lower steel tower (12). The bottom of the anchor (21) penetrates the transition section (13) and is anchored to the inner wall of one side of the transition section (13); The anchor (21) and the connector (22) apply opposing tension forces to the lower steel tower (12) from different directions.

2. The anchorage conversion node of the hybrid wind power generation tower according to claim 1, characterized in that: The anchor (21) includes a straight section (211), a curved section (212) located at the bottom of the straight section (211), a fixed end (213) located at the top of the straight section (211), and a tensioning end (214) located on the side of the curved section (212) away from the straight section (211).

3. The anchorage conversion node of the hybrid wind power generation tower according to claim 2, characterized in that: The transition section (13) includes an upper section (131) disposed at the top of the concrete tower (11), an inclined section (133) connected to the bottom of the upper section (131), and a lower section (132) connected to the bottom of the inclined section (133). The concrete tower (11) has a cavity (111) inside, and the tensioning end (214) extends through the inclined section (133) into the cavity (111).

4. The anchorage conversion node of the hybrid wind power generation tower according to claim 3, characterized in that: An anchoring device (25) is provided on one side of the tensioning end (214), and the tensioning end (214) is fixed to the side of the inclined section (133) near the cavity (111) by the anchoring device (25).

5. The anchoring conversion node of the hybrid wind power generation tower according to claim 4, characterized in that: The bottom of the lower steel tower (12) is provided with an external line hole (23), and the fixed end (213) passes through the external line hole (23) and is fixed to the bottom of the lower steel tower (12) on the side away from the cavity (111).

6. The anchorage conversion node of the hybrid wind power generation tower according to claim 5, characterized in that: A grouting channel (24) is provided on one side of the concrete tower (11). An outer protective pipe (215) is provided on the outer wall of the straight section (211) and the curved section (212). The outer protective pipe (215) penetrates the inner wall of the upper section (131) and the middle section (132). The grouting channel (24) is connected to the outer protective pipe (215).

7. The anchoring conversion node of the hybrid wind power generation tower according to claim 6, characterized in that: The connector (22) includes a steel strand (221) and a steel strand tensioning end (222) disposed on the top of the steel strand (221).

8. The anchoring conversion node of the hybrid wind power generation tower according to claim 7, characterized in that: The bottom of the lower steel tower (12) is also provided with an inner wire hole (26), and the tensioning end (222) of the steel strand passes through the inner wire hole (26) and is fixed to the bottom of the lower steel tower (12) near the cavity (111).

9. The anchorage conversion node of the hybrid wind power generation tower according to claim 8, characterized in that: The lower steel tower (12) is topped with an upper steel tower (14).

10. A construction method for the anchorage conversion node of a hybrid wind power generation tower, characterized in that: The method includes the anchoring conversion node of the hybrid wind power generation tower according to any one of claims 1 to 9, and comprises the following steps: An outer sleeve (215) is fitted onto the anchor (21), and it is pre-embedded in the transition section (13) together with the connector (22). At the same time, a grouting channel (24) is reserved in the transition section (13) to connect with the outer sleeve (215); Place the transition section (13) on the ground and position the tooling. Lift the lower steel tower (12) and splice it with the transition section (13). Pass the connector (22) through the inner hole (26) of the cylinder and anchor its upper end to the bottom of the lower steel tower (12). After all components are installed, the anchor (21) is initially tensioned under ground conditions. When using the bonded prestressed scheme, after tensioning is completed, grouting is carried out into the transition section (13) through the grouting channel (24) so ​​that the outer protective pipe (215) is filled with grout. After the grout hardens, the grouting channel (24) is sealed. When using the unbonded prestressing scheme, there is no need to grout the inside of the outer protective tube (215) after tensioning; Lift the transition section (13) containing the lower steel tower (12), install it on top of the concrete tower (11), anchor the bottom end of the connector (22) to the bottom foundation of the tower, and tension the connector (22); If an unbonded prestressing scheme is adopted, the anchor (21) needs to be tensioned again after the tensioning of the connector (22) is completed; The anchorage at the upper end of the anchor (21) is sealed with anti-corrosion material to prevent rainwater from seeping in.

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