A wind power concrete tower circumferential prestress reinforcing device and wind power concrete tower

Abstract

The utility model discloses a kind of wind power concrete tower cylinder hoop prestress reinforcing devices, including shape memory alloy plate (1021), bolt (1022) for connecting the shape memory alloy plate (1021), and structural adhesive layer (1023) being arranged between the shape memory alloy plate (1021) and vertical concrete component outer surface.The device can effectively inhibit the generation and expansion of concrete tower cylinder crack, prolong the service life of wind power tower cylinder, construction is simple and adapts to complex environment on site, with good applicability and durability.

Description

Technical Field

[0001] This utility model relates to civil engineering reinforcement devices, and more particularly to a circumferential prestressed reinforcement device for wind power concrete towers and a wind power concrete tower. Background Technology

[0002] The concrete tower of a wind turbine is a crucial vertical load-bearing component supporting the nacelle and rotor, and must withstand significant vertical pressure, circumferential tensile stress, and wind-induced cyclic loads throughout its entire lifespan. With increasing service life, the concrete sections of the tower may develop cracks in the circumferential, vertical, and diagonal directions under long-term loads, environmental erosion, temperature gradient changes, and occasional extreme wind conditions. If these cracks are not controlled in a timely manner, they will lead to a decrease in structural stiffness and load-bearing capacity, threatening the safe operation of the wind turbine. Due to the massive size of the tower and the complex construction environment, complete demolition or replacement is extremely costly. Therefore, efficient and reliable reinforcement of cracked areas in existing towers has become a key focus in the industry.

[0003] Existing methods for repairing and reinforcing concrete sections of wind turbine towers include external steel plate cladding, cross-section enlargement, and circumferential steel hoop reinforcement. While external steel plate cladding is convenient to construct, it has high durability and maintenance costs, and is susceptible to corrosion in offshore wind power environments. Enlarging the cross-section increases the tower's weight, affecting its overall dynamic performance, and is also more complex to construct. Circumferential steel hoop reinforcement requires significant prestressing force to provide restraint, but applying uniform prestressing to large concrete towers is difficult during construction. These methods may experience efficiency decline or maintenance difficulties in the long term, and they cannot provide effective active prestressed reinforcement repair, failing to repair existing cracks and damaged areas, thus failing to fully meet the requirements for high durability and maintenance-free operation of wind turbine towers.

[0004] Iron-based shape memory alloys (Fe-SMA) are functional alloy materials that, after being deformed by external force within a certain temperature range, can recover their original shape upon heating; this shape recovery characteristic is known as the shape memory effect. When the free recovery deformation of Fe-SMA is restricted during heating, a large recovery stress can be generated (the specific value can be achieved through design). This stress can be effectively introduced into the circumferential prestress of the tower concrete section, thereby improving the structure's crack resistance and load-bearing capacity. Compared with traditional steel, Fe-SMA has significant advantages in corrosion resistance, fatigue resistance, and ease of construction. Compared with traditional prestressed steel strand reinforcement methods, prestressed CFRP reinforcement technology, and cross-section enlargement reinforcement methods, prestressed Fe-SMA has significant advantages in terms of ease of construction and feasibility at high altitudes.

[0005] Therefore, there is an urgent need to design a circumferential reinforcement structure specifically for wind turbine concrete towers, which can use Fe-SMA material to quickly apply controllable prestress on site to close tower cracks and restore structural performance, while ensuring safety during high-altitude construction and long-term service durability. Summary of the Invention

[0006] Purpose of the utility model: The purpose of this utility model is to provide a circumferential prestressed reinforcement device for wind power concrete towers and a wind power concrete tower. This reinforcement device can effectively reinforce areas on the surface of wind power concrete towers that have cracked or are at risk of cracking, thereby improving structural safety, durability and disaster resistance.

[0007] Technical solution: The wind power concrete tower circumferential prestressed reinforcement device and wind power concrete tower of this utility model include a shape memory alloy plate, bolts for connecting the shape memory alloy plate, and a structural adhesive layer disposed between the shape memory alloy plate and the outer surface of the wind power concrete tower.

[0008] Furthermore, the shape memory alloy plate is made of iron-based shape memory alloy material Fe-SMA.

[0009] Furthermore, the shape memory alloy plate generates pre-strain through pre-stretching and pre-stress through thermal excitation, with an activation temperature of 150℃-400℃ and a pre-strain of 2%-8%.

[0010] Furthermore, the structural adhesive layer is a high-temperature resistant structural adhesive.

[0011] Furthermore, the bolts are spaced circumferentially.

[0012] Another aspect of this utility model provides a vertical concrete component installed inside the circumferential prestressed reinforcement device for the wind power concrete tower.

[0013] Furthermore, the wind power concrete tower is a prestressed and non-prestressed vertical concrete component.

[0014] The reinforcement method of the circumferential prestressed reinforcement device for wind power concrete towers of this utility model involves naming the area on the outer surface of the wind power concrete tower that has cracked or is at risk of cracking as the area to be reinforced, pre-treating the area to be reinforced and the shape memory metal, determining the shape of the area to be reinforced, wrapping the area to be reinforced with the pre-treated shape memory metal, and performing thermal excitation to make the shape memory metal wrap the wind power concrete tower.

[0015] Furthermore, if the area to be reinforced is a circular cross-section concrete tower section, the pre-stretched Fe-SMA reinforcing plate is wrapped circumferentially and fully adhered to the adhesive layer, and then fixed with bolts.

[0016] If the area to be reinforced is a polygonal or irregular cross-section tower section, the pre-stretched Fe-SMA reinforcement plate should be bonded to the adhesive layer as much as possible and gradually fixed with bolts to achieve effective anchoring.

[0017] For the iron-based shape memory metal in the reinforced area, a segmented thermal excitation method is adopted.

[0018] The structural adhesive layer is preferably a high-temperature resistant and aging-resistant epoxy structural adhesive or a modified epoxy structural adhesive, which has good bonding performance and thermal stability, so as to achieve effective bonding between the shape memory alloy plate and the concrete tower surface, prevent local voids, and improve the overall reinforcement effect.

[0019] The shape memory alloy plate is made of iron-based shape memory alloy material. It generates pre-strain through pre-stretching and pre-stress through thermal excitation to achieve circumferential constraint on the concrete tower.

[0020] The bolts are arranged circumferentially at specific intervals for mechanical connection and fixation of the shape memory alloy plate, preventing slippage and ensuring the stability and integrity of the reinforced structure.

[0021] A circumferential prestressed reinforcement structure and method for wind turbine concrete towers (including prestressed and non-prestressed vertical concrete structures and components such as steel-concrete composite wind turbine concrete towers, cooling towers, and silos). The reinforcement structure includes circumferential reinforcement components disposed on the outer surface of the wind turbine concrete tower. These components are composed of pre-stretched iron-based shape memory alloy plates, which generate restoring stress through thermal excitation to achieve effective circumferential constraint on the concrete tower. The reinforcement components are mechanically connected by bolts and supplemented with a high-temperature resistant structural adhesive layer to enhance the adhesion between the shape memory alloy plates and the concrete surface, ensuring the stability and durability of the overall structure. The reinforcement method includes surface pretreatment of the area to be reinforced, cutting pre-stretched shape memory alloy plates to wrap the area to be reinforced, and activating the shape memory alloy plates using a segmented thermal excitation method to generate prestress, tightly adhering to and reinforcing the concrete tower.

[0022] Compared with the prior art, this utility model has the following advantages: 1. By using a combination of structural adhesive and bolts, or one of them alone, a strong bond is achieved between the shape memory alloy plate and the wind power concrete tower, improving the reliability and durability of the reinforcement.

[0023] 2. The circumferential prestress generated by the shape memory alloy plate effectively constrains the concrete tower, reduces the risk of crack propagation, and extends the service life of the wind turbine tower.

[0024] 3. The construction process is simple, requiring no complex prestressing tensioning equipment, making it suitable for construction environments with limited space and high-altitude construction, and adaptable to concrete towers of various cross-sectional shapes. Furthermore, this invention strengthens the structure without damaging the original structure, representing a novel non-destructive active reinforcement method. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the circumferential prestressed reinforcement device for wind turbine concrete towers. Figure 2 A schematic diagram of the detailed structure of the node of the circumferential prestressed reinforcement device for a wind turbine concrete tower. Figure 3 This is a schematic diagram of the reinforcement of a wind turbine concrete tower using a circumferential prestressed reinforcement device in an actual engineering project (Schematic diagram of Fe-SMA plate reinforcement of a damaged wind turbine concrete tower). Figure 4 This is a cross-sectional view of the circumferential prestressed reinforcement device for wind turbine concrete towers in actual engineering applications. Detailed Implementation

[0026] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make corresponding modifications and extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0027] As used herein, "an embodiment" or "an embodiment" refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor are they mutually exclusive.

[0028] This utility model is described in detail with reference to the accompanying drawings. For ease of explanation, the cross-sectional views showing the device structure are not enlarged to scale, and the drawings are merely examples and should not limit the scope of protection of this utility model. In actual manufacturing, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0029] Reference Figures 1 to 4 This embodiment provides a circumferential prestressed reinforcement device and method for wind turbine concrete towers, specifically including: The main structure 100 includes a wind power concrete tower 101 and a circumferential reinforcement component 102 adapted to be installed on its outer side; The circumferential reinforcement component 102 includes a shape memory alloy plate 1021, bolts 1022 for connecting the shape memory alloy plate, and a high-temperature resistant structural adhesive layer 1023 disposed between the shape memory alloy plate 1021 and the outer surface of the wind power concrete tower 101.

[0030] In practice, the area to be reinforced is first pretreated by mechanical grinding and cleaning to remove dirt and old coatings, ensuring that the concrete surface is rough and clean in order to improve the bonding effect of the structural adhesive.

[0031] The Fe-SMA plate is pre-cut into a ring shape, with a length covering the perimeter of the area to be reinforced, a width of approximately 200 mm, and a thickness of 3 mm. The Fe-SMA plate is then pre-stretched at room temperature using a specialized tensile testing device, with the tensile strain controlled at approximately 4%, to create a pre-strained state.

[0032] After pre-stretching, the Fe-SMA plate undergoes plastic deformation and enters the plastic stage, thus weakening the plate's stiffness and allowing it to adhere tightly to the surface of the wind turbine tower. Compared to steel plate reinforcement, the pre-bending process is not required.

[0033] Apply a 2-3mm thick layer of high-temperature resistant epoxy structural adhesive 1023 evenly to the surface of the area to be reinforced. Then wrap the pre-stretched Fe-SMA board around the area to be reinforced in the circumferential direction to ensure a tight fit to the coated surface. Fix it evenly in the circumferential direction with bolts 1022 to prevent slippage and detachment.

[0034] After the structural adhesive is applied, the reinforced area should be cured at room temperature for no less than 3 days to ensure that the structural adhesive has reached its best bonding performance. After curing, the activation process of the Fe-SMA board can begin.

[0035] This embodiment employs a segmented heating activation process to thermally excite the Fe-SMA plates. Specifically, the Fe-SMA plates are heated to a predetermined activation temperature (150℃-400℃, determined based on the prestress required in the specific construction plan). The relationship between the recovery prestress generated after activation and the activation temperature is shown in the table below. To ensure sufficient and uniform activation, the activation equipment is moved circumferentially along the Fe-SMA plates after activation to continue heating until all Fe-SMA plates are fully activated.

[0036] The segmented heating method effectively avoids the risk of thermal stress concentration and structural adhesive softening failure caused by overall heating, ensuring good adhesion between the Fe-SMA plate and the concrete surface and stable prestress application. The activated Fe-SMA plate generates shrinkage prestress, circumferentially confining the concrete tower, effectively closing cracks, and enhancing load-bearing capacity and durability.

[0037] Table 1. Fe-SMA recovery stress at different activation temperatures

[0038] Note: Column 1 in the table represents the pre-tension strain used in the Fe-SMA plate, and columns 2-7 represent the recovery stress generated by Fe-SMA at different activation temperatures of 150-400℃ under the corresponding pre-tension strain.

[0039] The dual connection of structural adhesive and mechanical bolts used in this embodiment ensures the overall stability and durability of the reinforced structure. The segmented heating activation process improves construction safety and controllability, adapts to concrete towers of various cross-sectional shapes, and is simple to construct, requiring no complex prestressing application and anchoring equipment, making it suitable for site-constrained and high-altitude environments.

[0040] This reinforcement structure and method effectively reinforces cracked or potentially cracked areas of wind turbine concrete towers, significantly improving the safety and service life of the tower structure without damaging the original structure.

[0041] Reference Figure 2 The circumferential prestressed reinforcement device for wind turbine concrete towers provided by this utility model consists of concrete 103, Fe-SMA plates, bolts 1022, and structural adhesive 1023. Its design fully considers high-altitude construction, stress transfer, and long-term durability. The Fe-SMA plates are arranged circumferentially along the tower, tightly adhering to the outer surface of the concrete, and form a composite connection with the structural adhesive through bolts. The thickness of the structural adhesive layer at the joints needs to be increased according to the thickness of the bolt heads.

[0042] The choice of this node type is based on the fact that the concrete tower of wind power in actual projects is relatively large, with a diameter of about 6-8m and a circumference of 20m. However, in actual projects, it is impossible to complete the bonding and construction of such large Fe-SMA plates at high altitudes. Therefore, it is necessary to connect them in segments. Damage to wind turbine towers during service can prevent them from operating normally and generating electricity, resulting in huge direct economic losses. Therefore, construction efficiency needs to be given special attention, and choosing a faster construction method is necessary. Furthermore, for the reinforcement of the concrete tower of the wind turbine in service, since it is a tall structure with extremely high safety requirements, the destructive reinforcement method of drilling holes with anchor bolts and fixing Fe-SMA plates is not allowed. Therefore, only non-destructive reinforcement methods can be adopted. Simply using structural adhesive for bonding cannot guarantee an effective connection after the adhesive's performance deteriorates due to aging. Furthermore, it requires high-temperature activation of the Fe-SMA board to introduce prestress, a process that may soften the structural adhesive, leading to slippage and ultimately reducing the reinforcement effect. Therefore, simple structural adhesive bonding is not recommended in Fe-SMA reinforcement methods that introduce prestress through heat activation.

[0043] Therefore, taking into full account the actual structural characteristics, long-term durability requirements, construction condition limitations, and construction efficiency, the following approach was adopted. Figure 2 The node configuration shown satisfies the above conditions.

[0044] Before thermal activation, the plate is pre-stretched at room temperature to form a pre-strain state. When the plate is activated by heat, its shape memory effect causes the plate to generate shrinkage force, which is evenly transferred to the concrete surface through the adhesive layer and bolts to form a circumferential constraint force, effectively closing cracks and enhancing the overall load-bearing capacity of the tower.

[0045] Bolts are evenly distributed circumferentially along the plate in the joint, with the bolt heads inverted and embedded in the structural adhesive. This design not only fixes the position of the Fe-SMA plate, but also increases the contact area between the bolts and the adhesive layer, allowing the plate shrinkage force to be distributed throughout the joint area, avoiding local stress concentration and plate slippage.

[0046] This bolt embedding method enables the node to withstand the shear and peeling forces generated during the thermal activation process, while ensuring the stability of the structural adhesive at high temperatures, forming a reliable stress-bearing system.

[0047] Structural adhesive is placed between the lower surface of the Fe-SMA plate and the concrete tower. Its thickness can be appropriately increased according to the bolt head size to ensure uniform prestress transmission and provide a buffering effect at local stress concentration points.

[0048] The adhesive layer not only enhances the bond between the slab and the concrete, but also allows the circumferential prestress generated by the shrinkage of the Fe-SMA slab to play its full role.

[0049] Through the combined action of bolts and structural adhesive, a composite load-bearing system of plate-adhesive-concrete is formed, achieving a balance between joint stability and long-term durability.

[0050] The innovation of this node design lies in achieving completely non-destructive reinforcement. Through bolt fixing and structural adhesive bonding, the thermally activated shrinkage force of the Fe-SMA plate can be safely and efficiently transferred to the concrete tower, realizing self-actively applied circumferential prestress.

[0051] The inverted bolts embedded in the adhesive layer not only improve the load-bearing capacity of the joint, but also effectively reduce the risk of local stress concentration; the thickness of the structural adhesive is adjustable, allowing the joint to adapt to different bolt specifications and uneven concrete surfaces.

[0052] In addition, this node design takes into account both construction safety and controllability, making it suitable for construction at heights and in confined environments, and significantly outperforming traditional single bolt fixing or overall adhesive node reinforcement effects.

[0053] Through this node design, the shape memory effect and shrinkage prestress of the Fe-SMA plate can be fully applied to the tower structure, achieving the goals of crack closure, load-bearing capacity enhancement, and long-term durability reinforcement, while keeping the original tower structure intact.

[0054] Figure 3 The circumferential arrangement diagram for reinforcing cracked wind turbine concrete towers with Fe-SMA plates includes a concrete tower 101, Fe-SMA plates, nodes 104, and cracks 105. Figure 4 This is a top view of its cross-section.

[0055] Figure 3 The thickness of the structural adhesive is preferably 2-4 mm, the tower diameter is preferably 6-8 m, and the width of the Fe-SMA plate is preferably 200 mm and the thickness is preferably 3 mm.

[0056] like Figure 3 As shown, the non-node area is the activation zone of the Fe-SMA plate. During construction, it is heated to the phase transformation temperature using a heat source such as a flame torch, causing the plate to undergo a reverse phase transformation from martensite to austenite and generating shrinkage recovery stress. This stress is converted into circumferential prestress under the constraint of concrete, closing and compressing cracks, significantly improving the circumferential bearing capacity and durability of the tower. After reinforcement, Fe-SMA can generate approximately 200-260 MPa of prestress, producing 5-10 MPa of prestress on the tower concrete.

[0057] Fe-SMA plates are arranged circumferentially along the tower, closely adhering to the concrete surface, covering cracks and potentially high-risk areas to ensure that the prestressing effect is concentrated on the parts that most need reinforcement.

[0058] The marked "connection node area" refers to the anchoring end of the plate, which is fixed to the tower surface using bolts and structural adhesive, without thermal activation. This design avoids the anchoring area being affected by high temperatures, thus preventing a reduction in adhesive performance, while ensuring the stability of the bolted connection and allowing the shrinkage force in the activated area to be evenly transferred to the concrete structure through the node.

[0059] The overall reinforcement system consists of an activation zone, a node zone, and a concrete parent structure. Activation zone: Provides circumferential shrinkage prestress to achieve crack closure and reinforcement of the concrete compressive stress zone; Node area: Fixes and transmits contraction force, ensuring system stability and safety; Concrete parent structure: bears and distributes circumferential compressive stress, improving overall stiffness and load-bearing capacity.

[0060] This design balances efficient reinforcement with structural integrity, and boasts advantages such as high controllability, reactivation capability, and ease of construction.

[0061] The non-activated node design ensures that the bolt fixation and adhesive layer are stable and unaffected by high-temperature thermal activation, while maintaining the integrity of the original tower structure and achieving non-destructive reinforcement.

[0062] The activation zone of the Fe-SMA plate is arranged along the crack or damaged concrete area. After thermal activation, it generates circumferential shrinkage prestress. Through the composite stress system of Fe-SMA plate-structural adhesive-concrete, the compressive stress is applied to the crack, closing the crack and enhancing the tower's load-bearing capacity.

[0063] The diagram also marks the crack lines, showing that the Fe-SMA plate can cover and reinforce the cracked area after activation, thereby strengthening the structure and improving its durability. The reinforced and repaired concrete tower can operate normally during its service life.

[0064] Overall, Figure 3 The design demonstrates a rational division between the reinforcement nodes and the activation area: the activation area is used to apply circumferential prestress to close the cracks, while the node area is fixed to the position of the plate with bolts and structural adhesive, ensuring the stability, safety and efficiency of the reinforcement system, while avoiding damage to the tower structure itself, thus achieving an innovative design of non-destructive reinforcement.

[0065] It is important to understand that the inventive constructions and arrangements shown in the various exemplary embodiments are merely illustrative examples and not limiting. Although several embodiments are described in detail in this disclosure, those skilled in the art will readily understand that various equivalent modifications or improvements can be made without materially departing from the novel teachings and technical advantages of the subject matter described herein.

[0066] For example, the dimensions, proportions, structural shapes, parameter values ​​(such as temperature, pressure, etc.), installation arrangements, material selection, color, or orientation of each component in this utility model can be appropriately adjusted or replaced according to specific needs. The integrally formed component shown can also be composed of multiple parts or units, and the positions of the components can be inverted or changed in other ways. The properties, quantity, and positions of the discrete components can also be adjusted accordingly. Therefore, all such modifications are considered to fall within the protection scope of this utility model.

[0067] Furthermore, the "apparatus and its function" clause in any claim is intended to cover apparatuses having a corresponding structure to achieve the function, including both structurally equivalent and functionally equivalent variant structures.

[0068] Without departing from the scope of this utility model, the design, operation mode and arrangement of the exemplary embodiments can be replaced, modified, altered or omitted. Therefore, this utility model is not limited to a specific embodiment, but should cover all equivalent variations and improvements that conform to the appended claims.

[0069] Furthermore, for the sake of brevity, the exemplary embodiments may not describe all features in detail, that is, minor features that are irrelevant to the best mode of implementing the present invention or do not affect the essential function of the present invention are not described.

[0070] It should be clearly pointed out that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that any modifications, substitutions or equivalent transformations made to the technical solution without departing from the spirit and scope of this utility model should be considered as included within the scope of protection of the claims of this utility model.

Claims

1. A circumferential prestressed reinforcement device for wind turbine concrete towers, characterized in that: It includes a shape memory alloy plate (1021), bolts (1022) for connecting the shape memory alloy plate (1021), and a structural adhesive layer (1023) disposed between the shape memory alloy plate (1021) and the outer surface of the wind power concrete tower.

2. The circumferential prestressed reinforcement device for wind power concrete towers according to claim 1, characterized in that: The shape memory alloy plate (1021) is made of Fe-SMA, an iron-based shape memory alloy material that generates pre-strain through pre-stretching and pre-stress through thermal excitation.

3. The circumferential prestressed reinforcement device for wind power concrete towers according to claim 1, characterized in that: The structural adhesive layer (1023) is a high-temperature resistant structural adhesive.

4. The circumferential prestressed reinforcement device for wind power concrete towers according to claim 1, characterized in that: The bolts (1022) are arranged circumferentially at intervals.

5. A wind turbine concrete tower installed inside the prestressed reinforcement device according to any one of claims 1-4.

6. The wind power concrete tower according to claim 5, characterized in that: For both prestressed and non-prestressed concrete wind turbine towers.

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