Concrete tower segment joint reinforcement device and construction method

Abstract

The present application relates to a kind of concrete tower piece joint reinforcing device and construction method, upper tower piece is set in the upper of lower tower piece, the reinforcing device includes sleeve and connecting plate, the upper end both sides of the inner and outer wall of lower tower piece are connected with sleeve respectively, the sleeve of the upper end both sides of the inner and outer wall of lower tower piece is connected with each other by connecting plate, upper tower piece is set on connecting plate, the surface of the sleeve is provided with weld nail, after the device is set on lower tower piece, lower tower piece is poured to realize the connection between lower tower piece and connecting plate and sleeve, the weld nail is embedded in lower tower piece, after upper tower piece is set on device, filler is filled to fill the gap between the inner and outer wall of upper tower piece and connecting plate, sleeve, the weld nail is embedded in filler.Compared with prior art, the present application can avoid the stress concentration of tower section joint position to cause tower piece to be damaged under pressure, also improve the transverse shear resistance of tower piece in use stage.

Description

Technical Field

[0001] The invention belongs to the technical field of super-high tower construction and relates to a concrete tower segment joint reinforcement device and a construction method. Background Art

[0002] With the rapid development of the wind power industry, total installed wind turbine capacity continues to increase, with single-unit capacity rising from hundreds of kilowatts to multiple megawatts. This places higher demands on wind turbine towers. Currently, prefabricated concrete towers are the mainstream choice in the wind power industry. Currently, most tower segments have dry-jointed horizontal joints, often bonded with epoxy adhesive. This bonding method is relatively weak, leading to defects such as cracking, collapse, and falling apart at the joints. Furthermore, dry-jointed joints hinder tower segment leveling, making them susceptible to various defects.

[0003] Patent CN214272173U discloses a comprehensive emergency rescue structure for bridge pile foundation debonding. The structure comprises a debonding area, a steel sleeve, underwater concrete seal, the pile foundation, and a steel cofferdam. Underwater concrete seals are cast at a specific location below the debonding area, and a steel sleeve is installed above the seal. Self-compacting concrete is then poured into the sleeve. This patent is suitable for reinforcing existing structures. While the steel sleeve provides a good clamping effect, the bond between the sleeve and the main structure is poor. Furthermore, this patent is applicable to monolithic pile columns and does not enhance the bond between the upper and lower tower segments.

[0004] Patent CN210797265U discloses a slow-bond weld and a steel-concrete composite beam employing the slow-bond weld. The beam comprises a steel structure and a concrete slab, which are connected integrally using slow-bond welds. Prestressed steel strands are post-tensioned on the concrete slab. However, this patent applies to beam structures and is not directly applicable to hollow concrete wind turbine towers. Summary of the Invention

[0005] The purpose of the present invention is to provide a concrete tower segment joint reinforcement device and construction method in order to overcome at least one defect of the above-mentioned prior art, such as the relatively weak concrete tower segment joints. The present invention can avoid the compressive damage of the tower segment caused by stress concentration at the joints between tower sections, and also improve the lateral shear and bearing capacity of the tower segment during use.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] One of the technical solutions of the present invention is to provide a concrete tower joint reinforcement device, the upper tower plate is arranged above the lower tower plate, the reinforcement device includes a sleeve and a connecting plate, the upper ends of the inner and outer walls of the lower tower plate are respectively connected to the sleeves, the sleeves on both sides of the upper ends of the inner and outer walls of the lower tower plate are connected to each other through the connecting plates, the inner and outer sleeves and the connecting plates are combined into an H-shaped configuration, the upper tower plate is mounted on the connecting plate to achieve the connection between the upper tower plate and the lower tower plate, welding nails are provided on the surface of the sleeve, the device is sleeved on the lower tower plate and then the lower tower plate is cast to achieve the connection between the lower tower plate and the connecting plate and sleeve, the welding nails are buried in the lower tower plate, the upper tower plate After the tower piece is erected on the device, fillers are poured to fill the inner and outer walls of the upper tower piece and the gaps between the connecting plates and sleeves. The rivets are buried in the fillers. The inner and outer sleeves can enhance the compressive strength of the tower piece joints, prevent crushing damage caused by local stress concentration, and increase the circumferential shear bearing capacity of the tower piece. At the same time, they have a waterproof effect and can protect prestressed tendons and steel bars from rust. The connecting plates can connect the inner and outer sleeves to facilitate construction. The rivets enhance the bonding effect between the reinforcing device and the tower piece and the fillers, thereby enhancing the integrity and rigidity of the tower piece. The fillers enhance the bonding between the upper and lower tower pieces, enhance the overall performance and rigidity of the structure, and participate in the load-bearing together with the reinforcing device.

[0008] Furthermore, the inner side of the upper end of the inner wall of the lower tower segment is connected to the inner sleeve, and the outer surface of the inner sleeve is vertically connected to the connecting plate. The inner sleeve and the outer sleeve together participate in the overall force of the structure, thereby strengthening the compressive resistance and circumferential shear bearing capacity of the tower segment joint position.

[0009] Furthermore, the outer side of the upper end of the outer wall of the lower tower plate is connected to the outer sleeve, and the inner surface of the outer sleeve is vertically connected to the connecting plate.

[0010] Furthermore, a welding nail is provided on the outer surface of the inner sleeve below the connecting plate, the nail head end of the welding nail is connected to the outer surface of the inner sleeve, and the nail cap end faces the outer sleeve;

[0011] The welding nails are embedded in the lower tower plate, and the welding nails enhance the bonding effect between the reinforcing device and the tower plate, thereby enhancing the integrity and rigidity of the tower plate.

[0012] Furthermore, a welding nail is provided on the inner surface of the outer sleeve below the connecting plate, the nail head end of the welding nail is connected to the inner surface of the outer sleeve, and the nail cap end faces the inner sleeve;

[0013] The welding nails are embedded in the lower tower plate, and the welding nails enhance the bonding effect between the reinforcing device and the tower plate, thereby enhancing the integrity and rigidity of the tower plate.

[0014] Furthermore, a welding nail is provided on the outer surface of the inner sleeve above the connecting plate, the nail head end of the welding nail is connected to the outer surface of the inner sleeve, and the nail cap end faces the outer sleeve;

[0015] After the lower end of the upper tower piece is arranged on the upper surface of the connecting plate, the pouring filler fills the gap between the inner wall of the upper tower piece and the connecting plate and the inner sleeve, and the welding nail is embedded in the filler, and the welding nail enhances the bonding effect of the reinforcing device and the filler, thereby enhancing the integrity and rigidity of the tower piece.

[0016] Further, the inner surface of the outer sleeve is provided with a welding nail above the connecting plate, and the nail head end of the welding nail is connected with the inner surface of the outer sleeve, and the nail cap end faces the inner sleeve.

[0017] After the lower end of the upper tower piece is arranged on the upper surface of the connecting plate, the pouring filler fills the gap between the inner wall of the upper tower piece and the connecting plate and the inner sleeve, and the welding nail is embedded in the filler, and the welding nail enhances the bonding effect of the reinforcing device and the filler, thereby enhancing the integrity and rigidity of the tower piece.

[0018] Further, the inner sleeve is connected with the outer sleeve through the spaced connecting plates, that is, the connecting mode between the inner sleeve and the outer sleeve selects repeated connecting plate-blank-connecting plate, the laying object connects the inner sleeve and the outer sleeve, and a gap is left for leveling, and the spaced connecting plates are also arranged to facilitate leveling.

[0019] As a preferred technical solution, the area of the blank is equal to the area of the connecting plate.

[0020] As a preferred technical solution, the material of the lower tower piece is concrete, and the material of the upper tower piece is steel.

[0021] Further, the materials of the inner sleeve, the connecting plate, the outer sleeve and the welding nail are all steel, the material of the laying object is mortar, and the material of the filler is concrete.

[0022] One of the technical solutions of the present application is to provide a concrete tower piece joint construction method, which uses the reinforcing device to reinforce the joint position of the concrete tower piece, and the method comprises the following steps:

[0023] S1, prefabricate the inner sleeve, the outer sleeve and the welding nail in the factory, uniformly and reasonably weld the welding nail on the inner sleeve and the outer sleeve, and space the connecting plate and weld it in the middle position between the inner sleeve and the outer sleeve;

[0024] S2, fix the prefabricated reinforcing device above the lower tower piece by using the support, so that the connecting plate is just at the top end of the lower tower piece, install the support and the formwork, and pour the main body of the lower tower piece;

[0025] S3, transport the prefabricated lower tower piece to the designated position;

[0026] S4. After the lower tower pieces are hoisted, a thin layer of paving material is poured at the connection plate at the joint position and leveled;

[0027] S5. After the paving material solidifies, the upper tower piece is hoisted and the filling material is poured between the inner sleeve, the outer sleeve and the upper tower piece body;

[0028] S6. Subsequent construction can be carried out after the filling material solidifies.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The steel-concrete prefabricated reinforced joint (inner and outer sleeves) of the present invention provides additional circumferential constraints for the wind turbine tower segments, forming a hoop effect, thereby enhancing the local pressure bearing capacity of the wind turbine tower segment at the joint position, thereby avoiding stress concentration at the joint position between tower sections, which may cause damage to the tower segments and local crushing. It also improves the transverse shear bearing capacity of the wind turbine tower segments during use, thereby ensuring the stability of the wind turbine tower segment during the construction stage of tensioning the prestressed tendons.

[0031] (2) The present invention provides a connecting plate between the inner and outer sleeves, which can connect the inner and outer sleeves together to form a whole, so that they can share the load, thereby improving the integrity and rigidity of the structure and also improving construction efficiency. The spaced connecting plates facilitate leveling.

[0032] (3) The present invention achieves a bonding effect between the H-shaped inner sleeve, connecting plate and outer sleeve combined reinforcement device and the concrete tower piece by welding nails;

[0033] (4) The present invention casts a thin layer of paving material at the joint position after the lower tower piece is hoisted, which can help the upper tower piece to be leveled, avoid the structure from deflecting before prestressing, which endangers the personal safety of construction workers, and improve the local pressure bearing capacity and integrity of the joint position;

[0034] (5) The present invention enhances the waterproof performance of the tower section through the circumferential steel-concrete joint, avoiding the phenomenon of cracking and leakage at the joint position after the pressure in the tension zone of the tower section is relieved;

[0035] (6) The reinforcement device of the present invention adopts a prefabricated cast-in-place combination method, which can better utilize the construction method of prefabricated assembly of wind turbine tower pieces, and at the same time greatly improves the bonding effect of the upper and lower tower pieces. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the overall assembly of a concrete tower segment joint reinforcement device according to an embodiment of the present invention;

[0037] Figure 2 Schematic diagram of the overall structure of the concrete tower segment joint reinforcement device in an embodiment of the present invention;

[0038] Figure 3 It is a sectional assembly schematic view of the concrete tower piece joint reinforcing device in the embodiment of the application.

[0039] Figure 4 It is a partial enlarged assembly schematic view of the concrete tower piece joint reinforcing device in the embodiment of the application.

[0040] Figure 5 It is a partial enlarged structural schematic view of the concrete tower piece joint reinforcing device in the embodiment of the application.

[0041] Marking in the figure:

[0042] 1 - lower tower piece, 2 - upper tower piece, 31 - inner sleeve, 32 - connecting plate, 33 - outer sleeve, 34 - welding pin, 4 - filler. DETAILED DESCRIPTION

[0043] The application will be described in detail below in combination with specific embodiments. The embodiments are implemented on the premise of the technical scheme of the application, and detailed implementation modes and specific operation processes are given, but the protection scope of the application is not limited to the following embodiments.

[0044] In the description of the application, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application. In addition, the terms "first", "second", "third", etc. are used to describe common objects, only to indicate different instances of the same object, and do not imply that the objects thus described must be in a given order, whether in time, space, order or any other manner.

[0045] In the description of the application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0046] Embodiment:

[0047] A concrete tower piece joint reinforcing device is applied to the horizontal joint reinforcement of an upper tower piece 2 and a lower tower piece 1 of a fabricated wind turbine tower, like Figures 1 to 5 As shown, the upper tower piece 2 is arranged above the lower tower piece 1, and the reinforcement device includes a sleeve and a connecting plate 32. The upper ends of the inner and outer walls of the lower tower piece 1 are respectively connected to the sleeves, and the sleeves on both sides of the upper ends of the inner and outer walls of the lower tower piece 1 are connected to each other through the connecting plate 32. The inner and outer sleeves and the connecting plate 32 are combined into an H-shaped configuration. The upper tower piece 2 is connected to the lower tower piece 1 by being mounted on the connecting plate 32. A welding nail 34 is provided on the surface of the sleeve. The device is installed above the lower tower piece 1 and then the lower tower piece 1 is cast to realize the connection between the lower tower piece 1 and the connecting plate 32 and the sleeve. The welding nail 34 is buried in the lower tower piece 1. The upper tower piece 2 is mounted on the device The post-cast filler 4 fills the inner and outer walls of the upper tower piece 2 and the gap between the connecting plate 32 and the sleeve. The welding nail 34 is embedded in the filler 4. The inner and outer sleeves can strengthen the compressive strength of the tower piece joint position, prevent the crushing damage caused by local stress concentration, and increase the circumferential shear bearing capacity of the tower piece. At the same time, it has a waterproof effect and can protect the prestressed tendons and steel bars from rust. The connecting plate 32 can connect the inner and outer sleeves to facilitate construction. The welding nail 34 enhances the bonding effect between the reinforcement device and the tower piece and the filler 4, thereby enhancing the integrity and rigidity of the tower piece. The filler 4 enhances the bonding between the upper and lower tower pieces, enhances the overall performance and rigidity of the structure, and participates in the force together with the reinforcement device.

[0048] The inner side of the upper end of the inner wall of the lower tower segment 1 is connected to the inner sleeve 31, and the outer surface of the inner sleeve 31 is vertically connected to the connecting plate 32. The inner sleeve 31 and the outer sleeve 33 participate in the overall stress of the structure, strengthening the compressive strength and hoop shear bearing capacity of the tower segment joint position;

[0049] The outer side of the upper end of the outer wall of the lower tower plate 1 is connected to the outer sleeve 33, and the inner surface of the outer sleeve 33 is vertically connected to the connecting plate 32;

[0050] A welding nail 34 is provided on the outer surface of the inner sleeve 31 below the connecting plate 32. The nail head end of the welding nail 34 is connected to the outer surface of the inner sleeve 31, and the nail cap end faces the outer sleeve 33.

[0051] The welding nails 34 are embedded in the lower tower plate 1. The welding nails 34 enhance the bonding effect between the reinforcing device and the tower plate, thereby enhancing the integrity and rigidity of the tower plate.

[0052] A welding nail 34 is provided on the inner surface of the outer sleeve 33 below the connecting plate 32. The nail head end of the welding nail 34 is connected to the inner surface of the outer sleeve 33, and the nail cap end faces the inner sleeve 31.

[0053] The welding nails 34 are embedded in the lower tower plate 1. The welding nails 34 enhance the bonding effect between the reinforcing device and the tower plate, thereby enhancing the integrity and rigidity of the tower plate.

[0054] A welding nail 34 is provided on the outer surface of the inner sleeve 31 above the connecting plate 32. The nail head end of the welding nail 34 is connected to the outer surface of the inner sleeve 31, and the nail cap end faces the outer sleeve 33.

[0055] After the lower end of the upper tower segment 2 is mounted on the upper surface of the connecting plate 32, the filler 4 is poured to fill the inner wall of the upper tower segment 2 and the gap between the connecting plate 32 and the inner sleeve 31. The welding nails 34 are embedded in the filler 4. The welding nails 34 enhance the bonding effect between the reinforcing device and the filler 4, thereby enhancing the integrity and rigidity of the tower segment.

[0056] A welding nail 34 is provided on the inner surface of the outer sleeve 33 above the connecting plate 32. The nail head end of the welding nail 34 is connected to the inner surface of the outer sleeve 33, and the nail cap end faces the inner sleeve 31.

[0057] After the lower end of the upper tower segment 2 is mounted on the upper surface of the connecting plate 32, the filler 4 is poured to fill the outer wall of the upper tower segment 2 and the gap between the connecting plate 32 and the outer sleeve 33. The welding nails 34 are embedded in the filler 4. The welding nails 34 enhance the bonding effect between the reinforcing device and the filler 4, thereby enhancing the integrity and rigidity of the tower segment.

[0058] Before the upper tower piece 2 is erected on the device, the paving material is poured on the connecting plate 32. The inner sleeve 31 is connected to the outer sleeve 33 through the spaced connecting plates 32. That is, the connection between the inner sleeve 31 and the outer sleeve 33 adopts a repeated connecting plate 32-blank-connecting plate 32. The area of ​​the blank can be equal to the area of ​​the connecting plate 32. The paving material connects the inner and outer sleeves, leaving a gap for easy leveling. The spaced arrangement of the connecting plates 32 is also for easy leveling.

[0059] The material of the lower tower plate 1 is self-compacting concrete, which is convenient for construction, shortens the construction period and increases the strength. The material of the upper tower plate 2 is weathering steel plate, which can improve the corrosion resistance, prevent rust and enhance the durability.

[0060] The materials of the inner sleeve 31, the connecting plate 32, the outer sleeve 33 and the welding nails 34 are all weather-resistant steel plates, which can improve the corrosion resistance, prevent rust and enhance the durability. The material of the paving is epoxy resin mortar, which further enhances the bonding effect of the upper and lower tower plates. The material of the filler 4 is self-compacting concrete, which facilitates construction, shortens the construction period and increases strength.

[0061] A method for constructing joints of concrete tower segments, using the aforementioned reinforcement device to strengthen the joints of concrete tower segments, includes the following specific steps:

[0062] S1. Prefabricate the inner sleeve 31, outer sleeve 33 and welding pins 34 in the factory, weld the welding pins 34 evenly and reasonably to the inner sleeve 31 and outer sleeve 33, and weld the connecting plate 32 at intervals to the middle position between the inner sleeve 31 and outer sleeve 33;

[0063] S2. Use a bracket to fix the prefabricated reinforcement device above the lower tower piece 1 so that the connecting plate 32 is just at the top of the lower tower piece 1, and install the bracket and formwork, and cast the main body of the lower tower piece 1;

[0064] S3, transporting the prefabricated lower tower piece 1 to the designated location;

[0065] S4. After the lower tower piece 1 is hoisted, a thin layer of paving is poured at the connection plate 32 at the joint position and leveled;

[0066] S5. After the paving material solidifies, the upper tower piece 2 is hoisted and the filling material 4 is poured between the inner sleeve 31, the outer sleeve 33 and the main body of the upper tower piece 2;

[0067] S6. After the filler 4 solidifies, subsequent construction can be carried out.

[0068] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A concrete tower joint reinforcement device, characterized in that: The upper tower plate (2) is arranged above the lower tower plate (1); the reinforcing device comprises a sleeve and a connecting plate (32); the upper ends of the inner and outer walls of the lower tower plate (1) are respectively connected to the sleeves; the sleeves on the upper ends of the inner and outer walls of the lower tower plate (1) are connected to each other through the connecting plate (32); the upper tower plate (2) is mounted on the connecting plate (32); welding nails (34) are arranged on the surface of the sleeve; the device is mounted on the lower tower plate (1) and then the lower tower plate (1) is cast to realize the connection between the lower tower plate (1), the connecting plate (32) and the sleeve; the welding nails (34) are embedded in the lower tower plate (1); the upper tower plate (2) is mounted on the device and then a filler (4) is cast to fill the inner and outer walls of the upper tower plate (2) and the gap between the connecting plate (32) and the sleeve; the welding nails (34) are embedded in the filler (4).

2. A concrete tower segment joint reinforcement device according to claim 1, characterized in that: The inner side of the upper end of the inner wall of the lower tower plate (1) is connected to the inner sleeve (31), and the outer surface of the inner sleeve (31) is vertically connected to the connecting plate (32).

3. A concrete tower segment joint reinforcement device according to claim 2, characterized in that: The outer side of the upper end of the outer wall of the lower tower plate (1) is connected to the outer sleeve (33), and the inner surface of the outer sleeve (33) is vertically connected to the connecting plate (32).

4. A concrete tower segment joint reinforcement device according to claim 3, characterized in that: A welding nail (34) is provided on the outer surface of the inner sleeve (31) below the connecting plate (32), the nail head end of the welding nail (34) is connected to the outer surface of the inner sleeve (31), and the nail cap end faces the outer sleeve (33); The welding nails (34) are embedded in the lower tower plate (1).

5. The concrete tower segment joint reinforcement device according to claim 3, characterized in that: A welding nail (34) is provided on the inner surface of the outer sleeve (33) below the connecting plate (32), the nail head end of the welding nail (34) is connected to the inner surface of the outer sleeve (33), and the nail cap end faces the inner sleeve (31); The welding nails (34) are embedded in the lower tower plate (1).

6. The concrete tower segment joint reinforcement device according to claim 3, characterized in that: A welding nail (34) is provided on the outer surface of the inner sleeve (31) above the connecting plate (32), the nail head end of the welding nail (34) is connected to the outer surface of the inner sleeve (31), and the nail cap end faces the outer sleeve (33); After the lower end of the upper tower plate (2) is mounted on the upper surface of the connecting plate (32), a filler (4) is poured to fill the inner wall of the upper tower plate (2) and the gap between the connecting plate (32) and the inner sleeve (31), and the welding nail (34) is embedded in the filler (4).

7. The concrete tower segment joint reinforcement device according to claim 3, characterized in that: A welding nail (34) is provided on the inner surface of the outer sleeve (33) above the connecting plate (32), the nail head end of the welding nail (34) is connected to the inner surface of the outer sleeve (33), and the nail cap end faces the inner sleeve (31); After the lower end of the upper tower plate (2) is mounted on the upper surface of the connecting plate (32), a filler (4) is poured to fill the outer wall of the upper tower plate (2) and the gap between the connecting plate (32) and the outer sleeve (33), and the welding nails (34) are embedded in the filler (4).

8. The concrete tower segment joint reinforcement device according to claim 3, characterized in that: The upper tower plate (2) is erected on the device and the paving material is poured on the connecting plate (32). The inner sleeve (31) is connected to the outer sleeve (33) through the spaced connecting plate (32).

9. The concrete tower segment joint reinforcement device according to claim 8, characterized in that: The inner sleeve (31), the connecting plate (32), the outer sleeve (33) and the welding nail (34) are all made of steel, the paving material is made of mortar, and the filler (4) is made of concrete.

10. A method for constructing concrete tower segment joints, characterized in that: The method uses the reinforcement device according to any one of claims 1 to 9 to reinforce the joints of concrete tower segments, and the method comprises the following steps: S1. Prefabricate the inner sleeve (31), the outer sleeve (33) and the welding nails (34) in the factory, weld the welding nails (34) to the inner sleeve (31) and the outer sleeve (33), and weld the connecting plate (32) between the inner sleeve (31) and the outer sleeve (33) at intervals; S2. Using a bracket, fix the prefabricated reinforcement device above the lower tower plate (1) so that the connecting plate (32) is just at the top of the lower tower plate (1), and install the bracket and formwork, and cast the main body of the lower tower plate (1); S3, transporting the prefabricated lower tower piece (1) to a designated location; S4. After the lower tower piece (1) is hoisted, the paving material is poured at the connection plate (32) at the joint position and leveled; S5. After the paving material solidifies, the upper tower plate (2) is hoisted, and the filling material (4) is poured between the inner sleeve (31), the outer sleeve (33) and the main body of the upper tower plate (2); S6. The filling (4) solidifies.

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