Connector of wind power concrete tower drum and tower drum section

Abstract

The utility model discloses a wind power concrete tower drum connector and a tower drum segment, the connector comprises a tower drum inner bottom flange and a lower turnup pipe barrel, the lower turnup pipe barrel is coaxially welded and fixed on the inner wall of the tower drum inner bottom flange to obtain a ring groove, and the ring groove is filled with ultra-high performance concrete. According to the tower drum sections, the connectors are arranged at the upper end and the lower end of a common concrete pipe, and prestressed tendons penetrate through ultra-high performance concrete of the connectors and the common concrete pipe and are locked through prestressed anchorage devices. The construction method comprises the following steps: 1, prefabricating the inner bottom flange and the lower flanging pipe barrel of the tower barrel in a factory; 2, coaxially welding the inner bottom flange of the tower barrel and the lower flanging pipe barrel; 3, a connector is manufactured, and a common concrete pipe is manufactured; 4, hoisting in place in sequence on site; and 5, the prestressed steel bars penetrate through the tower drum sections and are locked through the prestressed anchorage devices. The method has the technical effects that the bearing capacity of concrete tower drum connection is enhanced, the anti-fatigue performance of the concrete tower drum joint and the overall stability of the tower drum are improved, and the construction cost is low.

Description

Technical Field

[0001] This utility model belongs to the field of wind power generation technology, and in particular relates to a concrete tower for offshore wind power. Background Technology

[0002] In recent years, with the global energy structure shifting towards a low-carbon model, wind energy, as a clean and renewable emerging energy source, has seen its installed capacity grow rapidly, bringing challenges in transportation, construction, and structural safety. To meet the requirements for tower height, precast concrete towers have gained widespread application due to their economy and ease of construction.

[0003] Precast concrete tower sections are typically prefabricated on shore and then transported to the construction site for hoisting and assembly. After each section is hoisted, leveling, positioning, grouting, and sealing operations are required at high altitudes, increasing construction steps and introducing significant safety risks. Furthermore, the large cross-section and high weight of concrete tower sections often necessitate prolonged operation with large lifting equipment for each section, significantly increasing hoisting costs and construction time. Existing tower section connection methods mainly include sleeve grouting connections, wet-cast joints, and structural adhesive bonding. Sleeve grouting connections rely on long sleeves and numerous reinforcing steel components, resulting in large joint dimensions, long bond lengths, and limited overall tensile and compressive strength. Wet-cast joints involve complex procedures requiring long curing times and are prone to interface cracks or poor bonding in unfavorable environments. Structural adhesive bonding is sensitive to the construction environment, making it difficult to guarantee bonding reliability and durability. To improve connection performance and assembly efficiency, existing technologies have proposed various improvement measures, such as using through-type prestressed steel cables to ensure joint stress sharing or using dry pre-tightened bolt connections. However, these improvements often increase the difficulty of component processing, require higher precision in component processing, and complicate on-site installation, which is equivalent to on-site construction conditions, thus losing the advantages of simple and economical construction of precast concrete towers.

[0004] Because offshore wind turbine concrete towers are subjected to complex wind and wave loads, cyclic loads, and corrosive environments over a long period of time, their structural stability and durability are worse than those of onshore wind turbines. Utility Model Content

[0005] To address the problems existing in the joints of existing concrete tower sections, this utility model aims to provide a joint for wind power concrete tower sections that enhances the load-bearing capacity of the joints, improves the fatigue resistance of the joints, and enhances the overall stability of the tower. This utility model also provides a concrete tower section.

[0006] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:

[0007] On the one hand, the connector of the wind power concrete tower provided by this utility model includes an inner bottom flange of the tower and a down-turned pipe. The down-turned pipe is coaxially fixed to the inner wall of the inner bottom flange of the tower. The vertical side and bottom side of the down-turned pipe and the inner wall of the inner bottom flange of the tower form an annular groove. The annular groove is filled with ultra-high performance concrete. The bottom side of the down-turned pipe has a prestressed tendon hole. The bottom side of the down-turned pipe and the flange of the inner bottom flange of the tower are spaced apart in the axial direction.

[0008] Secondly, the concrete tower segment provided by this utility model includes an ordinary concrete pipe, with connectors of this utility model installed at both the upper and lower ends of the ordinary concrete pipe. The ordinary concrete pipe is in contact with the ultra-high performance concrete of the connector, and the prestressed tendon passes through the ultra-high performance concrete of the connector and the ordinary concrete pipe. The two ends of the prestressed tendon are locked by prestressed anchors pressed against the bottom edge of the pipe of the upper and lower connectors.

[0009] Thirdly, this utility model provides a construction method for wind power concrete towers, including the following steps:

[0010] Step 1, Factory Prefabrication Stage: Process the inner bottom flange and the lower flange pipe of the tower separately, and install welding studs on the vertical and circumferential sides of the inner bottom flange and the vertical edge of the lower flange pipe.

[0011] Step 2: Use limiting components to position the inner bottom flange of the tower and the lower flange tube coaxially. The vertical side and bottom side of the lower flange tube are welded to the cylinder wall of the inner bottom flange of the tower to form an annular groove.

[0012] Step 3: Set bolt holes on the flange face of the inner bottom flange of each section of the tower and prestressing tendon holes on the bottom edge of each down-turned pipe. Pour ultra-high performance concrete into the annular groove formed between the inner bottom flange of the tower and the down-turned pipe to make a connector. At the same time, make ordinary concrete pipes. During the pouring of ultra-high performance concrete and the prefabrication of ordinary concrete pipes, open several through channels along the circumference and pre-embed sleeves in the channels.

[0013] Step 4: On-site, hoist the components in sequence and align the inner bottom flange of the tower section connector with the flange of the already installed tower section connector. Tighten the flange bolts to secure it. Hoist the ordinary concrete pipe and assemble it with the ultra-high performance concrete of the upper and lower connectors.

[0014] Step 5: In the ultra-high performance concrete and ordinary concrete pipe pre-embedded sleeves of the tower segment, prestressed steel bars are passed through, and prestressed anchors are installed at both ends of the prestressed steel bars. Tensioning and anchoring operations are carried out to complete the assembly of one tower segment. Until all tower segments are assembled, a wind power concrete tower is built.

[0015] The technical effects of this utility model are:

[0016] This invention replaces the existing grouting wet connection method with a flange connection for the joint, making the connection more reliable. The joint uses internal and external steel constraints and an ultra-high performance concrete interlayer, effectively reducing stress concentration and improving fatigue life. In the ultra-high performance concrete area of ​​the joint, the arrangement of welded studs and circumferential reinforcement enhances the bond strength between the ultra-high performance concrete interlayer and the steel, as well as the circumferential tensile strength. The tower segments of this invention utilize prestressed steel bars for penetration, prestressed anchorage for prestressing, and FRP fabric for joint reinforcement, improving the load-bearing capacity of the tower segments and meeting the stringent requirements for stability and durability of tall towers. The construction method of this invention combines factory prefabrication with rapid on-site assembly, significantly improving construction efficiency and reducing construction costs. Attached Figure Description

[0017] The accompanying drawings of this utility model are described below:

[0018] Figure 1 This is a structural diagram showing the combination of the upper and lower connectors;

[0019] a. Upper connector; b. Lower connector;

[0020] Figure 2 This is a cross-sectional view of the upper connector.

[0021] Figure 3 This is a schematic diagram of the structure of the down-turned-edge tube.

[0022] Figure 4 This is a structural schematic diagram of a concrete tower segment;

[0023] Figure 5 This is a diagram showing the distribution of weld studs along the circumference.

[0024] Figure 6 This is a diagram showing the distribution of welded studs on a vertical plane.

[0025] Figure 7 This is a diagram showing the distribution of circumferential reinforcement and stirrups on the circumferential surface.

[0026] In the diagram, 1. Ultra-high performance concrete; 2. Ordinary concrete pipe; 3. Inner bottom flange of the tower; 31. Flange bolt; 4. Downward-facing pipe; 41. Circumferential weld; 42. Local reinforcing rib; 5. Prestressed anchor; 51. Prestressed tendon; 52. Prestressed tendon hole; 7. FRP fabric; 12. Circumferential reinforcement; 13. Stirrup; 14. Welded stud. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0028] To clearly describe the content of the utility model, this patent application uses the directional terms "upper" and "lower" for distinction. The terms "upper" and "lower" are determined based on the layout orientation of the above drawings. If the actual use direction of this utility model changes, the terminology of the orientation will change accordingly, and this should not be regarded as a limitation on the scope of patent protection.

[0029] like Figure 1 and Figure 2 As shown, the wind power concrete tower connector (hereinafter referred to as "connector") provided by this utility model includes an inner bottom flange 3 of the tower and a down-turned pipe 4. The down-turned pipe 4 is coaxially welded and fixed to the inner wall of the inner bottom flange 3 of the tower. The vertical side and bottom side of the down-turned pipe 4 form an annular groove with the inner wall of the inner bottom flange 3 of the tower. The annular groove is filled with ultra-high performance concrete 1. The ultra-high performance concrete is used to strengthen the local bearing capacity and fatigue resistance of the transition section of the connector. Figure 3 As shown, the bottom edge of the down-flared tube 4 has prestressing tendon holes 52 for passing through prestressing tendons 51, and the prestress is tensioned by prestressing anchors 5. The bottom edge of the down-flared tube 4 and the flange of the inner bottom flange 3 of the tower are spaced axially to allow for tightening of the flange bolts 31 and the prestressing anchors 5 inside the tower. The upper connector a and the lower connector b are connected and fixed together by the inner bottom flange 3 of the tower and flange bolts 31.

[0030] The ultra-high performance concrete 1 is a cement-based composite material with high strength, high toughness, high density, and excellent durability. Its compressive strength after 28 days of setting can reach over 120 MPa, and its splitting tensile strength can reach over 10 MPa. According to the Chinese "Technical Specification for Application of Ultra-High Performance Concrete" (JGJ / T 439-2018) and the international "CEB-FIP Model Code 2010," ultra-high performance concrete is typically composed of a low water-cement ratio, a highly reactive cementitious material system, a continuously graded fine aggregate system, steel fibers, and a water-reducing agent. The ultra-high performance concrete used in this invention comprises the following components by mass: 380-480 parts cement, 80-130 parts silica fume, 150-250 parts fly ash, 80-130 parts microspheres, 450-550 parts natural sand, 350-480 parts crushed stone, 160-200 parts water, 10-20 parts water-reducing agent, and 160-200 parts steel fiber. The maximum particle size of the natural sand does not exceed 2.36 mm, and the maximum particle size of the crushed stone does not exceed 10 mm; both are designed with continuous gradation. The average particle size of the silica fume is 0.2-1 μm, the average particle size of the fly ash is 1-5 μm, and the particle size of the microspheres is <10 μm; the combination of these three components constitutes a highly active mineral admixture. The water-reducing agent is a polycarboxylate-based high-efficiency water-reducing agent. The steel fiber is straight in shape, with a diameter of 0.2 mm, a length of 13 mm, an aspect ratio of 190, and a tensile strength of not less than 2500 MPa.

[0031] like Figure 2 and Figure 3 As shown, the inner bottom flange 3 of the tower body refers to a hollow flange at the inner bottom of the tower body; the single-sided cross-section of the down-turned pipe 4 is "L" shaped, with the vertical side of the down-turned pipe maintaining a distance from the tower wall of the connector, and the horizontal side serving as a support platform for the ultra-high performance concrete 1. The down-turned pipe is located at the transition section of the connector, providing a pressure-bearing foundation for this section of the tower and the ordinary concrete section.

[0032] The aforementioned connector transition section is a local structure located at the connector, equipped with inner and outer steel and an ultra-high performance concrete interlayer. This section is used to enhance the strength and rigidity of the joint, improve the fatigue resistance and durability of the connector, prevent cracking or damage caused by local stress concentration, and achieve a smooth transition from the high-performance connector to the ordinary concrete cylinder section.

[0033] like Figure 1 and Figure 2 As shown, the down-turned pipe 4 is fixed to the inner wall of the tower by welding a circumferential weld 41 to the inner bottom flange 3 of the tower. The weld is a full weld. At the same time, local reinforcing ribs 42 are arranged circumferentially at the weld to prevent stress concentration and fretting fatigue on site. The local reinforcing ribs 42 are located below the bottom edge of the down-turned pipe 4 and are arranged between every two prestressed anchors 5.

[0034] like Figure 1 and Figure 5 As shown, welded studs 14 are evenly distributed circumferentially along the inner wall of the bottom flange 3 and the vertical edge of the down-turned pipe 4 of the tower. These welded studs 14 are embedded in ultra-high performance concrete 1, which improves the shear bearing capacity of the joint and the overall stability of the wind power concrete tower. Figure 6 As shown, the welded studs 14 are distributed in a quincunx pattern along the vertical side of the lower flange pipe 4 and the vertical surface of the inner wall of the inner bottom flange 3 of the tower, which can effectively transmit the shear force of the steel-concrete interface.

[0035] like Figure 1 and Figure 7 As shown, in the interlayer area formed by the bottom flange 3 and the vertical side of the down-turned pipe 4 inside the tower, circumferential steel bars 12 are arranged, and stirrups 13 are arranged along the vertical spacing to form a steel reinforcement skeleton. Then, ultra-high performance concrete 1 is filled in, which can enhance the circumferential tensile strength and local restraint of the joint.

[0036] like Figure 1 and Figure 4As shown, the concrete tower segment (hereinafter referred to as "tower segment") provided by this utility model includes an ordinary concrete pipe 2. Connectors of this utility model are installed at both the upper and lower ends of the ordinary concrete pipe 2. The ordinary concrete pipe 2 contacts the ultra-high performance concrete 1 of the connector. Prestressed tendons 51 penetrate the ultra-high performance concrete 1 of the connector and the ordinary concrete pipe 2. The two ends of the prestressed tendons 5 are locked by prestressed anchors 5 pressed against the bottom edge of the lower flange pipe 4 of the upper and lower connectors. The prestressed tendons 51 are used to combine the ordinary concrete pipe 2 and the connector into a tower segment and apply axial prestress.

[0037] Specifically, offshore wind turbine concrete towers require FRP (fiberglass reinforced plastic) fabric 7 to be wrapped around the joints between ultra-high performance concrete 1 and ordinary concrete pipe 2 to prevent seawater corrosion. Seawater primarily corrodes ordinary concrete and its internal reinforcing steel, especially the ordinary concrete at the joints. Because ultra-high performance concrete is dense and highly impermeable, and is protected by the inner bottom flange and the down-turned pipe, it is not easily eroded by seawater. Special protection is needed at the joints because they are both structurally weak points and areas with material interface differences, making them the most vulnerable to seawater erosion. Therefore, wrapping and sealing with FRP fabric 7 provides a high-strength, corrosion-resistant, and crack-resistant protective layer, blocking seawater and oxygen penetration and effectively extending the service life of the concrete tower segment. FRP fabric 7 consists of two main parts: fiber and resin. The fiber can be glass fiber, carbon fiber, aramid, etc., while the resin can be polyester resin, epoxy resin, etc.

[0038] This utility model provides a construction method for wind power concrete towers, including the following steps:

[0039] Step 1, Factory Prefabrication Stage: The inner bottom flange 3 and the lower flange tube 4 of the tower are processed separately. The inner bottom flange 3 of the tower is processed into a circular steel cylinder, and the lower flange tube 4 is processed into an inner lining section. Welded studs 14 are correspondingly installed on the vertical and circumferential sides of the tower wall and the vertical edge of the lower flange tube. The inner bottom flange 3 and the lower flange tube 4 are dimensionally matched.

[0040] Step 2: The inner bottom flange 3 and the lower flange tube 4 are coaxially fitted in the factory. The vertical and bottom edges of the lower flange tube 4 form an annular groove with the tower wall. After precise positioning by limiting components (limiting components are tools used for positioning during factory manufacturing, which can be used to determine the position of the inner bottom flange 3 and the lower flange tube 4 to keep them concentric), they are connected and fixed by multiple circumferential welds 41. At the same time, local reinforcing ribs 42 are arranged circumferentially at the weld below the bottom edge of the lower flange tube 4. After welding, circumferential steel bars 12 and vertical stirrups 13 are arranged in the annular groove formed by the inner bottom flange 3 and the vertical edge of the lower flange tube 4 to prefabricate the steel reinforcement skeleton.

[0041] Step 3: Set bolt holes on the flange face of the inner bottom flange 3 of each tower section and prestressing tendon holes 52 on the bottom edge of each down-turned pipe 4. Pour ultra-high performance concrete 1 into the annular groove formed between the inner bottom flange 3 and the down-turned pipe 4, and cure for no less than 7 days to form a connector. Set positioning marks on the inner bottom flange 3 of the tower to assist in on-site installation and positioning at sea. At the same time, pour ordinary concrete pipe 2 and cure for no less than 14 days. During the pouring of ultra-high performance concrete and the precast ordinary concrete pipe, open several through channels along the circumference. Embed sleeves or corrugated pipes in the channels for later penetration of prestressing tendons 51. Combine the ordinary concrete pipe 2 with the connector to form a tower section.

[0042] Step 4: Transport the connectors and ordinary concrete pipes to the installation site according to their numbers. During the tower installation process, first hoist the connectors into place, and use the inner bottom flange 3 of the tower to connect with the flange of the connector of the adjacent tower section. Tighten the flange bolts 31 to form a rigid connection. At the same time, according to the positioning number, hoist the ordinary concrete pipe 2 and connect it with the ultra-high performance concrete 1 of the upper and lower connectors.

[0043] Step 5: According to the numbered position, insert the prestressed steel bar 51 into the prestressed tendon hole 52 from the upper part of the tower segment, and use the prestressed anchor 5 for tensioning. After tensioning, anchor the prestressed steel bar through the anchor, and wrap FRP cloth 7 around the joint between the ultra-high performance concrete and the ordinary concrete pipe to complete the assembly of one tower segment. Continue to assemble all tower segments to build a wind power concrete tower.

[0044] The wind turbine concrete tower constructed according to the construction method of this utility model forms a new type of steel-concrete composite node tower segment with high fatigue resistance, excellent connection stiffness and on-site construction efficiency, which meets the requirements of long-term stability of wind turbine tower operation and prefabricated construction.

Claims

1. A windmill concrete tower connection, characterized in that: Including tower drum The inner bottom flange (3) and the lower flange pipe cylinder (4) are coaxially welded and fixed to the inner wall of the tower drum inner bottom flange (3), the vertical edge and the bottom edge of the lower flange pipe cylinder (4) and the inner wall of the tower drum inner bottom flange (3) form a ring groove, the ring groove is filled with ultra-high performance concrete (1), and the bottom edge of the lower flange pipe cylinder (4) is provided with a prestressed tendon hole (52); the bottom edge of the lower flange pipe cylinder (4) and the flange of the tower drum inner bottom flange (3) are spaced in the axial direction.

2. The wind turbine concrete tower section joint of claim 1, wherein: The lower flange pipe cylinder (4) is welded and fixed to the tower drum inner wall along the tower drum inner bottom flange (3) by using a circumferential weld (41), a local reinforcing rib (42) located below the bottom edge of the lower flange pipe cylinder is arranged along the circumferential weld, and the local reinforcing rib (42) is arranged between every two prestressed anchors (5).

3. A wind turbine concrete tower section joint according to claim 1 or 2, characterised in that: The inner wall of the tower drum inner bottom flange (3) and the vertical edge of the lower flange pipe cylinder (4) are uniformly arranged with welded dowels (14) along the circumference, the welded dowels (14) are embedded in the ultra-high performance concrete (1), and the welded dowels (14) are distributed in a quincunx shape along the vertical surface of the vertical edge of the lower flange pipe cylinder (4) and the inner wall of the tower drum inner bottom flange (3).

4. The wind turbine concrete tower section joint according to claim 1 or 2, characterized in that The interlayer region formed by the tower drum inner bottom flange (3) and the vertical edge of the lower flange pipe cylinder (4) is arranged with circumferential steel bars (12), and hoop bars (13) are arranged at a vertical spacing to form a steel reinforcement framework, and then filled with ultra-high performance concrete (1).

5. A concrete tower section comprising a plain concrete pipe (2) characterised in that: The ordinary concrete pipe (2) is provided with the connecting head of any one of claims 1-4 at both upper and lower ends, the ordinary concrete pipe (2) is in contact with the ultra-high performance concrete (1) of the connecting head, the prestressed tendon (51) penetrates through the ultra-high performance concrete (1) of the connecting head and the ordinary concrete pipe (2), and the prestressed tendon (51) is locked by the prestressed anchors (5) pressed by the bottom edges of the lower flange pipe cylinders (4) of the upper and lower connecting heads at both ends.

6. The concrete tower section of claim 5, characterized by: The FRP cloth (7) is wound around the joint between the ultra-high performance concrete (1) and the ordinary concrete pipe (2).

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