Connector of wind power concrete tower drum, tower drum section and tower drum construction method

Abstract

The invention discloses a connector of a wind power concrete tower drum, a tower drum section and a tower drum construction method, the connector comprises a tower drum inner bottom flange and a lower turnup pipe drum, the lower turnup pipe drum 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 tube 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] The present invention belongs to the technical field of wind power generation, and particularly relates to an offshore wind power concrete tower barrel and a construction method thereof. Background Art

[0002] In recent years, with the transformation of the global energy structure towards low carbonization, wind energy, as a clean and renewable emerging energy, has seen a continuous and rapid growth in its installed capacity, which also brings challenges in terms of transportation, construction, and structural safety. To meet the requirements of tower barrel height, precast concrete tower barrels have been widely used due to their economy and construction convenience.

[0003] Precast concrete tower barrels are usually precast from multiple barrel sections on shore and then transported to the construction site for hoisting and assembling. After each barrel section is hoisted, operations such as leveling, positioning, grouting, and sealing need to be carried out at high altitude, which not only increases the construction process but also brings greater safety risks. At the same time, the concrete tower barrel has a large cross-section and high self-weight, and each hoisting often requires large lifting equipment to operate for a long time, resulting in a significant increase in hoisting costs and construction period. The existing connection methods of tower barrel sections mainly include sleeve grouting connection, wet casting joint, and structural adhesive bonding, etc. Sleeve grouting connection relies on long sleeves and a large number of steel components, with large joint sizes, long bonding lengths, and limited overall tensile and compressive properties. The wet casting joint has cumbersome processes and requires long-term curing, and is prone to interface cracks or poor bonding when the environment is not good. Structural adhesive bonding is sensitive to the construction environment, and the bonding reliability and durability are difficult to guarantee. To improve the connection performance and assembly efficiency, various improvement measures have been proposed in the prior art. For example, using through prestressed steel cables for overall cable-pulling to make the joints work together or using dry pre-tightening bolts for connection. However, these improvement measures often increase the processing difficulty of components, require higher processing precision for components, and are complex in on-site installation, equivalent to the on-site construction state, losing the advantages of simple construction and cost savings of precast concrete tower barrels.

[0004] Due to the long-term exposure of offshore wind power concrete tower barrels to complex wind and wave loads, cyclic loads, and corrosive environment, their structural stability and durability are worse than those of onshore wind power. Summary of the Invention

[0005] Aiming at the problems existing in the connection of existing concrete tower barrels, the technical problem to be solved by the present invention is to provide a connection head for a wind power concrete tower barrel, which can enhance the bearing capacity of the connection of the concrete tower barrel, improve the anti-fatigue performance of the connection of the concrete tower barrel, and the overall stability of the tower barrel. The present invention also provides a concrete tower barrel section. It also provides a construction method for a wind power concrete tower barrel, which can simplify the on-site construction process, improve the installation efficiency, and reduce the project cost.

[0006] To solve the above technical problems, the technical solution of the present invention is as follows: On the one hand, the connector of the wind power concrete tower barrel provided by the present invention includes an inner bottom flange of the tower barrel and a downwardly flanged tube. The downwardly flanged tube is coaxially fixed to the inner wall of the inner bottom flange of the tower barrel. The vertical side and the bottom side of the downwardly flanged tube and the inner wall of the inner bottom flange of the tower barrel form an annular groove. Ultra-high performance concrete is filled in the annular groove. The bottom side of the downwardly flanged tube is provided with prestressed tendon holes, and there is a spacing between the bottom side of the downwardly flanged tube and the flange of the inner bottom flange of the tower barrel in the axial direction.

[0007] On the other hand, the concrete tower barrel segment provided by the present invention includes a normal concrete tube. The connectors of the present invention are installed at both the upper and lower ends of the normal concrete tube. The normal concrete tube is in contact with the ultra-high performance concrete of the connector. The prestressed tendons penetrate through the ultra-high performance concrete of the connector and the normal concrete tube, and both ends of the prestressed tendons are locked by prestressed anchors pressed against the bottom sides of the downwardly flanged tubes of the upper and lower connectors.

[0008] On the third hand, the present invention provides a construction method for a wind power concrete tower barrel, which includes the following steps: Step 1, in the factory prefabrication stage, the inner bottom flange of the tower barrel and the downwardly flanged tube are processed respectively, and welding studs are correspondingly arranged along the vertical direction and the circumferential direction on the barrel wall of the inner bottom flange of the tower barrel and the vertical side of the downwardly flanged tube. Step 2, use a limiting member to position the inner bottom flange of the tower barrel and the downwardly flanged tube coaxially, and weld the vertical side and the bottom side of the downwardly flanged tube and the barrel wall of the inner bottom flange of the tower barrel to form an annular groove. Step 3, set bolt holes on the flange surface of the inner bottom flange of each tower barrel segment and prestressed tendon holes on the bottom side of each downwardly flanged tube, and pour ultra-high performance concrete into the annular groove formed between the inner bottom flange of the tower barrel and the downwardly flanged tube to make a connector; at the same time, make a normal concrete tube. During the process of pouring ultra-high performance concrete and prefabricating the normal concrete tube, a number of through holes are opened along the circumference, and sleeves are embedded in the holes. Step 4, hoist and place them in sequence on site, dock the flange of the inner bottom flange of the connector with the flange of the connector of the already installed tower barrel segment, tighten and fix them with flange bolts, and hoist the normal concrete tube to dock and combine it with the ultra-high performance concrete of the upper and lower connectors. Step 5, penetrate the prestressed steel bars through the sleeves embedded in the ultra-high performance concrete and the normal concrete tube of the tower barrel segment, install prestressed anchors at both ends of the prestressed steel bars, and perform tensioning and anchoring operations to complete the assembly of one tower barrel segment until all tower barrel segments are assembled to build a wind power concrete tower barrel.

[0009] The technical effect of the present invention is: The connector of the present invention replaces the existing grouting wet connection method with a flange connection, making the connection of the connector more reliable; the connector uses internal and external steel constraints and a ultra-high performance concrete sandwich layer, effectively reducing stress concentration and increasing fatigue life; in the ultra-high performance concrete area of the connector, the arrangement of welded studs and circumferential steel bars enhances the bonding performance and circumferential tensile capacity between the ultra-high performance concrete sandwich layer and the steel. The tower barrel segment of the present invention uses prestressed steel bars to penetrate, prestressed anchors to apply prestressed anchoring, and FRP cloth to reinforce the joints, improving the mechanical properties of the tower barrel segment and meeting the strict requirements of high tower barrels for stability and durability. The construction method of the present invention combines factory prefabrication with on-site rapid assembly, greatly improving the construction efficiency and reducing the construction cost. Brief Description of the Drawings

[0010] The brief description of the drawings of the present invention is as follows: Figure 1 It is a schematic structural diagram of the combination of upper and lower connectors; a. Upper connector, b. Lower connector; Figure 2 It is a schematic cross-sectional structure diagram of the upper connector; Figure 3 It is a schematic structural diagram of the downward flanged tube; Figure 4 It is a schematic structural diagram of the concrete tower barrel segment; Figure 5 It is a distribution diagram of the welded studs along the circumference; Figure 6 It is a distribution diagram of the welded studs on the vertical plane; Figure 7 It is a distribution diagram of the circumferential steel bars and stirrups on the circumferential plane.

[0011] In the figures, 1. Ultra-high performance concrete; 2. Ordinary concrete pipe; 3. Inner bottom flange of the tower barrel; 31. Flange bolt; 4. Downward flanged tube; 41. Circumferential weld; 42. Local stiffening rib; 5. Prestressed anchor; 51. Prestressed steel bar; 52. Prestressed steel bar hole; 7. FRP cloth, 12. Circumferential steel bar; 13. Stirrup; 14. Welded stud. Detailed Embodiment

[0012] The present invention will be further described below with reference to the drawings and embodiments: For the purpose of clearly describing the content of the invention, the terms "upper" and "lower" are used in this patent application for distinction. The "upper" and "lower" are determined according to the layout direction of the above drawings. When the actual use direction of the present invention changes, the appellation of the direction changes accordingly, which cannot be regarded as a limitation of the patent protection scope.

[0013] As Figure 1 and Figure 2As shown in the figure, the wind power concrete tower barrel connector (hereinafter referred to as "connector") provided by the present invention includes a tower barrel inner bottom flange 3 and a downward flanging tube 4. The downward flanging tube 4 is coaxially welded and fixed to the inner wall of the tower barrel inner bottom flange 3. The vertical side and the bottom side of the downward flanging tube 4 and the inner wall of the tower barrel inner bottom flange 3 form an annular groove, and ultra-high performance concrete 1 is filled in the annular groove. The ultra-high performance concrete is used to enhance the local bearing capacity and anti-fatigue ability of the connector transition section; as Figure 3 shown, a prestressed tendon hole 52 is opened at the bottom of the downward flanging tube 4 for passing through the prestressed tendon 51, and the prestress is tensioned by the prestressed anchor 5; there is a spacing between the bottom of the downward flanging tube 4 and the flange of the tower barrel inner bottom flange 3 in the axial direction to facilitate tightening the flange bolts 31 and the prestressed anchor 5 inside the tower barrel. The upper connector a and the lower connector b are connected and fixed together through the tower barrel inner bottom flange 3 and the flange bolts 31.

[0014] The ultra-high performance concrete 1 is a cement-based composite material with high strength, high toughness, high density and excellent durability. The compressive strength after 28 days of setting can reach more than 120 MPa, and the splitting tensile strength reaches more than 10 MPa. According to the "Technical Specification for Application of Ultra-High Performance Concrete" (JGJ / T 439-2018) in China and the definition and specification of the "CEB-FIP Model Code 2010" internationally, ultra-high performance concrete usually consists of a low water-binder ratio, a highly reactive cementitious material system, a continuously graded fine aggregate system, steel fibers and water reducers. The components of the ultra-high performance concrete used in the present invention are calculated by mass as follows: 380-480 parts of cement, 80-130 parts of silica fume, 150-250 parts of fly ash, 80-130 parts of microspheres, 450-550 parts of natural sand, 350-480 parts of crushed stone, 160-200 parts of water, 10-20 parts of water reducer, and 160-200 parts of steel fibers. 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, and the two are designed according to a 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 <10 μm. The three are combined into a highly active mineral admixture. The water reducer is a polycarboxylate-based superplasticizer. The shape of the steel fiber is straight, the diameter is 0.2 mm, the length is 13 mm, the length-diameter ratio is 190, and the tensile strength is not less than 2500 MPa.

[0015] As Figure 2 and Figure 3 shown, the tower barrel inner bottom flange 3 means that the inner bottom of the tower barrel is a hollow flange plate; the single-sided cross-section of the downward flanging tube 4 is "L"-shaped, and there is a spacing between the vertical side of the downward flanging tube and the tower barrel wall of the connector, and the horizontal side serves as a support platform for the ultra-high performance concrete 1. The downward flanging tube is located at the connector transition section and provides a bearing foundation for this section of the tower barrel and the ordinary concrete section.

[0016] The described connector transition section is a local structure provided in the connector, configured with internal and external steel and a ultra-high performance concrete interlayer. This section is used to enhance the strength and stiffness of the joint part, improve the anti-fatigue performance 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.

[0017] As Figure 1 and Figure 2 shown, the downward-flanged pipe cylinder 4 is fixedly welded to the inner bottom flange 3 of the tower barrel along the inner wall of the tower barrel using a circumferential weld 41. The weld uses the full-weld process. At the same time, local stiffeners 42 are arranged circumferentially at the weld to prevent on-site stress concentration and fretting fatigue. The local stiffeners 42 are below the bottom edge of the downward-flanged pipe cylinder 4 and are arranged between every two prestressing anchors 5.

[0018] As Figure 1 and Figure 5 shown, welding studs 14 are evenly arranged circumferentially on the inner wall of the inner bottom flange 3 of the tower barrel and the vertical edge of the downward-flanged pipe cylinder 4. The welding studs 14 are embedded in the ultra-high performance concrete 1, which can improve the shear bearing capacity of the connector and the overall stability of the wind power concrete tower barrel. As Figure 6 shown, the welding studs 14 are distributed in a plum blossom shape on the vertical planes of the vertical edge of the downward-flanged pipe cylinder 4 and the inner wall of the inner bottom flange 3 of the tower barrel, and can effectively transfer the shear force at the steel-concrete interface.

[0019] As Figure 1 and Figure 7 shown, in the sandwich area formed by the inner bottom flange 3 of the tower barrel and the vertical edge of the downward-flanged pipe cylinder 4, circumferential steel bars 12 are arranged, and stirrups 13 are arranged at vertical intervals to form a steel bar framework, and then ultra-high performance concrete 1 is filled, which can enhance the circumferential tensile capacity and local constraint capacity of the connector.

[0020] As Figure 1 and Figure 4 shown, the concrete tower barrel segment (referred to as "tower barrel segment") provided by the present invention includes an ordinary concrete pipe 2. Connectors of the present invention are installed at both the upper and lower ends of the ordinary concrete pipe 2. The ordinary concrete pipe 2 is in contact with the ultra-high performance concrete 1 of the connector. Prestressing tendons 51 penetrate through the ultra-high performance concrete 1 of the connector and the ordinary concrete pipe 2, and both ends of the prestressing tendon 5 are locked by prestressing anchors 5 pressed against the bottom edges of the downward-flanged pipe cylinders 4 of the upper and lower connectors. The prestressing tendon 51 is used to combine the ordinary concrete pipe 2 and the connector into a tower barrel segment and apply axial prestress.

[0021] In particular, the wind power concrete tower installed at sea needs to be wrapped with FRP cloth 7 at the joint between the ultra-high performance concrete 1 and the ordinary concrete pipe 2 to prevent corrosion from seawater. The main objects of seawater corrosion are ordinary concrete and its internal steel bars, especially ordinary concrete at the joints. Since the ultra-high performance concrete itself is dense and impermeable, and is protected by the inner bottom flange and the lower flange tube of the tower, it is not easily corroded by seawater. The reason why the joints are specially protected is that the joints have structural weaknesses and material interface differences, and are the areas that are most likely to become the starting point of seawater erosion. Therefore, the use of FRP cloth 7 for winding and sealing can provide a high-strength, corrosion-resistant, and crack-resistant protective layer to block the penetration of seawater and oxygen, and effectively extend the service life of the concrete tower segment. The FRP cloth 7 is composed of two main parts: fiber and resin. The fiber can be glass fiber, carbon fiber, aramid, etc., and the resin can be polyester resin, epoxy resin, etc.

[0022] The present invention provides a construction method for a wind power concrete tower, comprising the following steps: Step 1, in the factory prefabrication stage, the inner bottom flange 3 of the tower and the lower flange tube 4 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 liner section, and welding studs 14 are correspondingly arranged on the vertical sides of the tower wall and the lower flange tube along the vertical and circumferential directions, and the inner bottom flange 3 of the tower and the lower flange tube 4 are matched in size.

[0023] Step 2, the tower inner bottom flange 3 and the lower flange tube 4 are coaxially sleeved in the factory, and the vertical side and bottom side of the lower flange tube 4 form an annular groove with the tower wall; after precise positioning by a limiting member (the limiting member is a tool used for positioning when made in the factory, which can be used to determine the position of the tower inner bottom flange 3 and the lower flange tube 4 to keep them concentric), they are connected and fixed through multiple annular welds 41, and at the same time, local reinforcing ribs 42 are arranged along the annular direction at the weld below the bottom side of the lower flange tube 4. After welding is completed, annular steel bars 12 and vertical stirrups 13 are arranged in the annular groove formed by the vertical sides of the tower inner bottom flange 3 and the lower flange tube 4 to prefabricate the steel skeleton.

[0024] Step 3, bolt holes are set on the flange surface of the inner bottom flange 3 of each segment and prestressed tendon holes 52 are opened on the bottom edge of each lower flange tube 4, ultra-high performance concrete 1 is poured into the annular groove formed between the inner bottom flange 3 of the tower and the lower flange tube 4, and cured for not less than 7 days to form a connector; positioning marks are opened on the inner bottom flange 3 of the tower to assist in on-site installation and positioning at sea; at the same time, ordinary concrete pipes 2 are poured and cured for not less than 14 days; in the process of pouring ultra-high performance concrete and prefabricating ordinary concrete pipes, a number of through channels are opened along the circumference, and sleeves or corrugated pipes are pre-buried in the channels for later penetration of prestressed tendons 51, and the ordinary concrete pipes 2 and the connectors are combined into tower segments.

[0025] Step 4: Transport the connector and the normal concrete pipes to the installation site according to the numbers. During the installation of the tower barrel, first hoist the connector into place, and butt the flange of the inner bottom flange 3 of the tower barrel with the flange of the connector of the adjacent tower barrel segment, and tighten and fix it through the flange bolts 31 to form a rigid connection. At the same time, according to the positioning numbers, hoist the normal concrete pipes 2 and dock and combine them with the ultra-high performance concrete 1 of the upper and lower connectors.

[0026] Step 5: According to the numbered positions, insert the prestressed steel bars 51 into the set prestressed tendon holes 52 from the upper part of the tower barrel segment, and use the prestressed anchor 5 for tensioning operations. After the tensioning is completed, anchor it through the anchor, and wind the FRP cloth 7 at the joint between the ultra-high performance concrete and the normal concrete pipe. Assemble one tower barrel segment, and continue until all the tower barrel segments are assembled to build a wind power concrete tower barrel.

[0027] The wind power concrete tower barrel built according to the construction method of the present invention forms a new steel-concrete composite joint tower segment with high fatigue resistance, excellent connection stiffness and on-site construction efficiency as a whole, meeting the long-term stability requirements of the wind power tower barrel operation and the needs of prefabricated construction.

Claims

1. A wind power concrete tower barrel connector, characterized in that: including a tower barrel an inner bottom flange (3) and a downward-flanged tube barrel (4), the downward-flanged tube barrel (4) is coaxially welded and fixed to the inner wall of the inner bottom flange (3) of the tower barrel, the vertical side and the bottom side of the downward-flanged tube barrel (4) form an annular groove with the inner wall of the inner bottom flange (3) of the tower barrel, ultra-high performance concrete (1) is filled in the annular groove, and a prestressed tendon hole (52) is opened at the bottom side of the downward-flanged tube barrel (4); there is a spacing between the bottom side of the downward-flanged tube barrel (4) and the flange of the inner bottom flange (3) of the tower barrel in the axial direction.

2. The wind power concrete tower barrel connector according to claim 1, characterized in that: The downward-flanged tube barrel (4) is welded and fixed to the inner bottom flange (3) of the tower barrel along the inner wall of the tower barrel using a circumferential weld (41), and local stiffeners (42) located below the bottom side of the downward-flanged tube barrel are arranged circumferentially along the weld, and the local stiffeners (42) are arranged between every two prestressing anchors 5.

3. The wind power concrete tower barrel connector according to claim 1 or 2, characterized in that: Welding studs (14) are evenly arranged circumferentially on the inner wall of the inner bottom flange (3) of the tower barrel and the vertical side of the downward-flanged tube barrel (4), the welding studs (14) are embedded in the ultra-high performance concrete (1), and the welding studs (14) are distributed in a plum blossom shape on the vertical surfaces of the vertical side of the downward-flanged tube barrel (4) and the inner wall of the inner bottom flange (3) of the tower barrel.

4. The wind power concrete tower barrel connector according to claim 1 or 2, characterized in that: at Circumferential steel bars (12) are arranged in the sandwich area formed by the inner bottom flange (3) of the tower barrel and the vertical side of the downward-flanged tube barrel (4), and stirrups (13) are arranged at intervals in the vertical direction to form a steel bar framework, and then ultra-high performance concrete (1) is filled.

5. A concrete tower barrel segment, comprising a normal concrete pipe (2), characterized in that: Connectors as described in any one of claims 1-4 are installed at both the upper and lower ends of the ordinary concrete pipe (2), the ultra-high performance concrete (1) of the ordinary concrete pipe (2) is in contact with the connectors, the prestressed tendons (51) penetrate through the ultra-high performance concrete (1) of the connectors and the ordinary concrete pipe (2), and both ends of the prestressed tendons (5) are locked by prestressing anchors (5) pressed against the bottom sides of the downward-flanged tube barrels (4) of the upper and lower connectors.

6. The concrete tower barrel segment according to claim 5, characterized in that: An FRP cloth (7) is wound at the joint between the ultra-high performance concrete (1) and the ordinary concrete pipe (2).

7. A construction method for a wind power concrete tower barrel, characterized in that including the following steps: Step 1, in the factory prefabrication stage, the inner bottom flange (3) and the downward-flanged tube barrel (4) are processed respectively, and welding studs (14) are correspondingly arranged on the barrel wall of the inner bottom flange (3) of the tower barrel and the vertical side of the downward-flanged tube barrel (4) along their vertical and circumferential directions; the inner bottom flange 3 of the tower barrel and the downward-flanged tube barrel 4 are processed respectively, and welding studs 14 are welded on the barrel wall of the inner bottom flange 3 of the tower barrel and the vertical side of the downward-flanged tube barrel 4. Step 2, the inner bottom flange (3) of the tower barrel and the downward-flanged tube barrel (4) are coaxially positioned using a limiting member, and the vertical side and the bottom side of the downward-flanged tube barrel (4) are welded to the barrel wall of the inner bottom flange (3) of the tower barrel to form an annular groove. Step 3, bolt holes are provided on the flange plate surface of the inner bottom flange (3) of each section of the tower barrel and prestressed tendon holes (52) are opened at the bottom side of each downward-flanged tube barrel (4), ultra-high performance concrete (1) is poured into the annular groove formed between the inner bottom flange (3) of the tower barrel and the downward-flanged tube barrel (4) to make a connector; at the same time, an ordinary concrete pipe (2) is made, and during the process of pouring ultra-high performance concrete and prefabricating the ordinary concrete pipe, a number of through holes are opened along the circumference, and sleeves are embedded in the holes. Step 4: Hoist and install in sequence on-site. Butt the inner bottom flange (3) of the connecting head of the tower barrel with the flange of the connecting head of the already installed tower barrel segment, and tighten and fix it with flange bolts (31). Hoist the normal concrete pipe (2) and butt and combine it with the ultra-high performance concrete (1) of the upper and lower connecting heads. Step 5: Insert prestressed steel bars (51) through the sleeves embedded in the ultra-high performance concrete and the normal concrete pipe of the tower barrel segment. Prestressed anchors (5) are installed at both ends of the prestressed steel bars (51), and tensioning and anchoring operations are carried out. One tower barrel segment is assembled, and all tower barrel segments are assembled until a wind power concrete tower barrel is built.

8. The construction method of the wind power concrete tower barrel according to claim 7, characterized in that: at In Step 2, local stiffeners (42) are arranged circumferentially at the weld at the bottom of the lower flanged pipe barrel (4), and a steel bar cage made of circumferential steel bars (12) and vertical stirrups (13) is set in the annular groove.

9. The construction method of the wind power concrete tower barrel according to claim 7, characterized in that: In Step 3, positioning marks are made on the inner bottom flange (3) of the tower barrel.

10. The construction method of the wind power concrete tower barrel according to claim 9, characterized in that: In Step 5, FRP cloth (7) is wound at the joint between the ultra-high performance concrete and the normal concrete pipe.

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