Square pier column template mechanism

Abstract

The invention discloses a square pier column formwork mechanism which comprises a formwork assembly. The formwork removing mechanisms are arranged on the periphery of the formwork assembly at intervals in the height direction of the formwork assembly, and each formwork removing mechanism comprises a hoop longitudinal beam, a hoop transverse beam and a hydraulic jack; the two hoop longitudinal beams and the two hoop cross beams are detachably connected to the periphery of the formwork assembly to form a square frame structure, the hoop longitudinal beams are detachably connected with the longitudinal formworks, the hoop cross beams are detachably connected with the transverse formworks, and the hydraulic jacks are connected between the hoop cross beams and the hoop longitudinal beams in a driving mode. The two hoop longitudinal beams or the two hoop cross beams can be pushed outwards at the same time through the synchronous jacking action of the multiple hydraulic jacks, meanwhile, the longitudinal formworks or the transverse formworks are driven to move outwards synchronously, and therefore rapid formwork removal of the formwork assembly is achieved, the formworks or concrete is prevented from being damaged, and the construction efficiency is improved. And the construction safety is ensured while the service life of the template assembly is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridge engineering construction, and in particular to a square pier column formwork mechanism. BACKGROUND

[0002] In bridge engineering construction, the dismantling of square pier column formwork is one of the key links in bridge engineering construction. After the pouring construction of the square pier column is completed, the formwork needs to be dismantled. At present, the traditional formwork dismantling method relies on manual operation, and the construction personnel need to use tools such as cranes and crowbars to complete a series of formwork dismantling steps such as loosening, lifting and transporting the formwork. This formwork dismantling mode has many drawbacks: on the one hand, manual formwork dismantling requires higher experience and skills of the operators, and the construction personnel have high labor intensity, which not only reduces the construction efficiency, but also makes it difficult to ensure the standardization of the formwork dismantling process, and the improper operation of the construction personnel may cause damage to the pier column surface, such as corner loss and edge loss, which adversely affects the engineering quality; on the other hand, manual formwork dismantling has poor adaptability to square pier column formworks of different specifications and sizes, and the work scheme needs to be adjusted every time the formwork type is changed, which is time-consuming and labor-intensive, and cannot meet the needs of diversified construction scenes. In addition, the traditional formwork dismantling process lacks effective data recording and monitoring means, and the traceability of the construction process is poor. Once a problem occurs, it is difficult to quickly locate the cause and take remedial measures; at the same time, the high degree of manual intervention also increases the safety risks, and accidents may occur during the lifting and transportation of the formwork. Therefore, the traditional manual formwork dismantling operation mainly has the problems of high manual intervention, low precision, low construction efficiency, poor adaptability and safety risks.

[0003] Chinese patent application with publication number CN120575500A discloses a bridge double-square-column pier formwork and a construction method, which includes a plurality of left formwork groups and right formwork groups. The left formwork groups and the right formwork groups are structurally identical and mirror-symmetrically opposite. Each left formwork group is composed of three outer side plates and an inner side plate. The outer side plates are provided with reinforcing ribs on their outer surfaces. The inner side plate is located in the gap between the double-square columns. An abutting assembly is installed between the left formwork group and the right formwork group. The abutting assembly includes a plurality of left sliding blocks horizontally slidingly installed on the inner side plate of the left formwork group and a plurality of right sliding blocks fixedly installed on the inner side plate of the right formwork group. The left sliding blocks and the right sliding blocks are in one-to-one correspondence.

[0004] When the formwork group is dismantled according to the technical scheme of the above-mentioned patent, the left sliding block is driven by the electric tool to gradually move away from the right sliding block, and the left sliding block exerts a pulling force on the outer side plate in the direction away from the pier to make the outer side plate separate from the formwork group. Although this can quickly achieve the dismantling of one of the outer side plates, the dismantling of the other two outer side plates and the inner side plate still needs to be performed by pulling them outward with a lifting device to achieve demolding, and the entire formwork group cannot be quickly dismantled. SUMMARY

[0005] The technical problem solved by the present application is to provide a square pier formwork mechanism capable of effectively reducing the difficulty of formwork removal and improving the formwork removal efficiency.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is: a square pier formwork mechanism, comprising a formwork assembly adapted to the square pier and composed of detachably connected longitudinal formworks and transverse formworks; and at least two groups of formwork removal mechanisms arranged at the periphery of the formwork assembly in the height direction of the formwork assembly, the formwork removal mechanism comprising hoop longitudinal beams, hoop transverse beams and hydraulic jacks; two hoop longitudinal beams and two hoop transverse beams are detachably connected to the periphery of the formwork assembly to form a square frame structure, the hoop longitudinal beams are detachably connected to the longitudinal formworks, the hoop transverse beams are detachably connected to the transverse formworks, and the hydraulic jacks are drivingly connected between the hoop transverse beams and the hoop longitudinal beams.

[0007] As an improvement of the above scheme: a plurality of buckles are fixedly arranged on the outer sides of the longitudinal formworks and the transverse formworks, the hoop longitudinal beams and the hoop transverse beams are connected to the formwork assembly by corresponding buckles.

[0008] As an improvement of the above scheme: a plurality of counter-pulling screws are further included, the hoop longitudinal beams and the hoop transverse beams are provided with through holes adapted to the counter-pulling screws; the hoop longitudinal beams and the hoop transverse beams are fixedly connected to the formwork assembly by corresponding counter-pulling screws.

[0009] As an improvement of the above scheme: the transverse formwork is an integrated formwork structure, and the longitudinal formwork is a split formwork structure composed of a plurality of formwork units detachably connected; the plurality of formwork units constituting the longitudinal formwork and the formwork units and the transverse formwork are detachably connected through the cooperation of bolt holes and bolts.

[0010] As an improvement of the above scheme: an operation platform is further arranged at the bottom of the formwork assembly, the operation platform is provided with a square hole adapted to the square pier, and the operation platform is fixedly arranged at the periphery of the square pier.

[0011] As an improvement of the above scheme: a plurality of sliding grooves are fixedly arranged on the operation platform and extend outward along the radial direction of the formwork assembly; the longitudinal formworks and the transverse formworks are slidingly connected to the sliding grooves through sliding blocks fixedly arranged at the bottom.

[0012] As an improvement of the above scheme: a limiting block is fixedly connected to the output end of the hydraulic jack, and the back surfaces of the hoop longitudinal beams and the hoop transverse beams are provided with limiting grooves extending along the length direction thereof; the limiting block connected to the output end of the hydraulic jack is embedded in the corresponding limiting groove to form a sliding fit.

[0013] As an improvement of the above scheme: two hydraulic jacks are arranged on each hoop longitudinal beam and each hoop transverse beam, the two hydraulic jacks are respectively fixed at two ends of the corresponding hoop longitudinal beam or hoop transverse beam, and the output ends of the hydraulic jacks are in sliding fit with two ends of the adjacent hoop transverse beam or hoop longitudinal beam.

[0014] The beneficial effects of the present application are: the present application sets the form stripping mechanism on the formwork assembly for pouring and forming the square pier column, the form stripping mechanism forms the frame structure for reinforcing the formwork assembly through the hoop longitudinal beam and the hoop transverse beam surrounding the periphery of the formwork assembly, which can provide stable support and reinforcement effect for the formwork assembly during the pouring process of the square pier column, so as to improve the overall strength of the formwork assembly; when the pouring construction is completed and the form stripping is performed, the two hoop longitudinal beams or the two hoop transverse beams can be simultaneously pushed outward through the synchronous jacking action of the plurality of hydraulic jacks, and the longitudinal formwork or the transverse formwork is simultaneously moved outward, so that the rapid form stripping of the formwork assembly is realized, the manual participation is reduced, the hard collision between the formwork and the poured concrete during the form stripping process can be effectively avoided, the formwork or the concrete is prevented from being damaged, the service life of the formwork assembly is improved, and the construction safety is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 Fig. 1 is a structural schematic view of a square pier column formwork mechanism; Figure 2 Fig. 2 is a structural schematic view of a formwork assembly.

[0016] In the figure, the marks are: 100-square pier column, 210-longitudinal formwork, 220-transverse formwork, 230-buckle, 240-pull screw, 250-bolt hole, 260-operation platform, 261-sliding groove, 310-hoop longitudinal beam, 320-hoop transverse beam, 330-hydraulic jack, 341-limiting block, 342-limiting groove. DETAILED DESCRIPTION

[0017] In order to facilitate the understanding of the present application, the present application will be further described below in combination with the drawings.

[0018] In the description of the present application, it should be noted that the terms “front”, “back”, “left”, “right”, “up”, “down”, “in” and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of description, and do not indicate or imply that the devices or components referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0019] As Figure 1As shown, the square pier formwork mechanism disclosed by the present application is composed of a formwork assembly and a formwork removal mechanism; the formwork assembly serves as a formwork for pouring and forming a square pier 100, and the formwork removal mechanism is used for reinforcing the formwork assembly and removing the formwork assembly after the pouring construction of the square pier 100 is completed.

[0020] Specifically, as shown in the drawings, Figure 1 and Figure 2 As shown, the formwork assembly used in the present application is composed of longitudinal formworks 210 and transverse formworks 220. Two longitudinal formworks 210 and two transverse formworks 220 are connected and enclosed to form a formwork assembly that is adapted to the square pier 100, and the formwork assembly is enclosed outside the square pier 100 to form a complete wrapping structure for the square pier 100 from four directions, which can preliminarily determine the overall position of the formwork and ensure that the coverage range matches the size of the square pier 100. In order to realize the quick assembly and disassembly of the formwork assembly, as shown in the drawings, Figure 2 the transverse formworks 220 adopt an integrated formwork structure, and the longitudinal formworks 210 adopt a split formwork structure, and the longitudinal formwork 210 is composed of multiple formwork units; the side edges of the formwork units and the side edges of the transverse formworks 220 are fixedly provided with reserved bolt holes 250, and these bolt holes 250 form a universal connection interface; multiple formwork units can be connected and assembled into a longitudinal formwork 210 through cooperation of bolts and bolt holes 250, and the longitudinal formwork 210 and the transverse formwork 220 can be connected and assembled into a formwork assembly. The longitudinal formwork 210 is set as a split combined formwork structure, which lays a foundation for flexible combination and disassembly of the formwork in different construction stages; during the construction stage of the square pier 100, the construction personnel only need to butt joint and fasten the formwork units through bolts to quickly combine into a complete longitudinal formwork 210; after the overall construction of the square pier 100 is completed and enters the construction stage of the capping beam, without replacing new formworks, only the bolts used for connection need to be removed, and the longitudinal formwork 210 can be disassembled into independent formwork units; then the disassembled formwork units are butt jointed and fastened with the transverse formwork 220 according to a new arrangement mode, and a capping beam side formwork system can be quickly formed. Through the modular design of the formwork assembly, the present application can effectively reduce the transfer and replacement process of the formwork during construction, avoid time waste and labor input caused by formwork replacement, and significantly improve the construction efficiency; and the formwork units that constitute the longitudinal formwork 210 can realize "one formwork for two purposes", form two kinds of formwork structures through different arrangement modes, reduce the construction investment cost, do not need to purchase formworks for different construction stages, and can bring good economic benefits to the bridge construction project.

[0021] Specifically, as shown in the drawings, Figure 1As shown, the form stripping mechanism used in the present application includes a hoop longitudinal beam 310, a hoop transverse beam 320 and a hydraulic jack 330, at least two groups of form stripping mechanisms are arranged at intervals along the height direction of the formwork assembly, a frame structure is formed on the periphery of the formwork assembly through the form stripping mechanism, the formwork assembly can be reinforced through the form stripping mechanism during the construction process of the square pier 100, and the formwork assembly can be quickly stripped after the pouring construction is completed. The hoop longitudinal beam 310 and the hoop transverse beam 320 are sequentially connected to form a square frame structure surrounding the periphery of the formwork assembly, the hoop longitudinal beam 310 is connected to the longitudinal form 210, the hoop transverse beam 320 is connected to the transverse form 320, and the fixation of the hoop longitudinal beam 310 and the hoop transverse beam 320 is realized through the buckle 230 fixed on the formwork assembly; a plurality of buckles 230 are arranged at intervals along the circumference of the formwork assembly, the hoop longitudinal beam 310 and the hoop transverse beam 320 are connected with the formwork assembly through the corresponding buckles 230; the buckle 230 adopts two bending buckle structures distributed upward and downward and fixed on the formwork assembly, the hoop longitudinal beam 310 and the hoop transverse beam 320 adopt a transversely inserted manner to form buckle cooperation with the buckle 230, and the buckle 230 engages and fixes the corresponding hoop longitudinal beam 310 or hoop transverse beam 320.

[0022] On the basis of the above-mentioned hoop longitudinal beam 310 and hoop transverse beam 320, the present application sets a hydraulic jack 330 between the hoop longitudinal beam 310 and the hoop transverse beam 320, and the hydraulic jack 330 is used to provide stripping power when the formwork assembly is disassembled. Specifically, as shown in the figure, Figure 1 As shown, one hydraulic jack 330 is installed at each end of each hoop longitudinal beam 310 and each hoop transverse beam 320, that is, two hydraulic jacks 330 are installed on each hoop longitudinal beam 310 and each hoop transverse beam 320, the cylinder body of the hydraulic jack 330 is fixed on the corresponding hoop longitudinal beam 310 or hoop transverse beam 320, and the output end of the hydraulic jack 330, that is, the piston rod, abuts against the adjacent hoop transverse beam 320 or hoop longitudinal beam 310, so that the power of the hydraulic jack 330 can be transmitted to the adjacent hoop transverse beam 320 or hoop longitudinal beam 310, and the hydraulic jack 330 can push the hoop transverse beam 320 or hoop longitudinal beam 310 matched with the piston rod outward. At the same time, in order to ensure that the movement of the hoop transverse beam 320 and the hoop longitudinal beam 310 under the thrust of the hydraulic jack 330 remains stable, the present application also guides and limits the movement of the hoop transverse beam 320 and the hoop longitudinal beam 310 under the drive of the hydraulic jack 330 through the cooperation of the limiting block 341 and the limiting groove 342. As shown in the figure, Figure 1As shown, the output end of the hydraulic jack 330 is fixedly connected with a limiting block 341, the back surface of the hoop longitudinal beam 310 and the hoop transverse beam 320 is provided with a limiting groove 342 extending along the length direction, and the limiting block 341 connected with the piston rod of the hydraulic jack 330 is embedded in the corresponding limiting groove 342 to form a sliding fit, so that the sliding of the limiting block 341 along the limiting groove 342 can ensure that the moving path of the hoop transverse beam 320 and the hoop longitudinal beam 310 remains horizontal. Through the limiting effect of the limiting groove 342 on the limiting block 341, the piston rod of the hydraulic jack 330 can be ensured to stretch and contract along a fixed direction, so that the transmission efficiency of the power is not affected by the deviation, and meanwhile, the stroke of the piston rod can be constrained to prevent damage caused by excessive stretching and contraction. Through the jacking effect of the hydraulic jack 330, when the formwork assembly is removed, the two hoop longitudinal beams 310 or the two hoop transverse beams 320 can be ensured to move synchronously outward along the radial direction of the formwork assembly, so that the formwork assembly or the poured pier column is not damaged due to uneven stress.

[0023] Through the integrated control center, the work of the hydraulic jack 330 can be remotely controlled. When the formwork assembly is removed, after the integrated control center sends a starting instruction, the hydraulic jack 330 fixed on the hoop transverse beam 320 starts according to a preset program, the piston rod of the hydraulic jack 330 extends to push the hoop longitudinal beam 310 matched therewith to translate outward, under the buckling effect of the buckle 230, the longitudinal beam 310 drives the longitudinal formwork 210 connected therewith to translate outward synchronously, so that the longitudinal formwork 210 is removed. Similarly, under the pushing of the hydraulic jack 330 fixed on the hoop longitudinal beam 310, the corresponding transverse formwork 220 is driven to translate outward by the translation of the hoop transverse beam 320, so that the transverse formwork 220 is removed. During the whole removal process, the display screen of the integrated control center can display the moving speed, position and other parameters of the formwork in real time, so as to be monitored by the operator in real time. Through the integrated control center, the intelligent formwork removal operation can be carried out, the stress state of the formwork can be dynamically monitored and accurately controlled, compared with the traditional manual formwork removal mode, the efficiency of the formwork removal operation can be improved by more than 90%, the hard collision between the formwork assembly and the poured concrete surface can be effectively avoided, the damage of the formwork can be reduced, so that the service life of the formwork can be significantly improved, and the construction safety can be ensured.

[0024] Further, in order to improve the stability of the formwork assembly, a plurality of tensioning screws 240 are arranged to reinforce the formwork assembly. Figure 1As shown, the hoop longitudinal beam 310 and the hoop transverse beam 320 are provided with through holes matched with the tensioning screw 240, one end of the tensioning screw 240 penetrates the formwork assembly and extends into the area to be poured in the formwork assembly, and the hoop longitudinal beam 310 and the hoop transverse beam 320 are fixed and tensioned with the formwork assembly through the corresponding tensioning screw 240. By arranging the tensioning screw 240, the hoop longitudinal beam 310 and the hoop transverse beam 320 can be further tensioned by the tension generated by the tensioning screw 240, which not only makes the formwork assembly tightly fold, but also ensures that the formwork assembly is tightly fitted with the square pier 100, thereby providing a stable and reliable structural foundation for subsequent construction and reducing the construction problems that may be caused by the loosening of the formwork assembly.

[0025] Further, as shown in Figure 1 and Figure 2 , the operation platform 260 is arranged at the bottom of the formwork assembly, a square hole matched with the square pier 100 is arranged at the center of the operation platform 260, the top of the square pier 100 that has been constructed in the previous stage is inserted into the square hole of the operation platform 260, and the operation platform 260 is fixed to the periphery of the square pier 100. A plurality of sliding grooves 261 are fixedly arranged on the operation platform 260 and extend outward along the radial direction of the formwork assembly, and the longitudinal formwork 210 and the transverse formwork 220 are slidably connected with the sliding grooves 261 through the sliding blocks fixed at the bottom. The sliding blocks and the sliding grooves 261 are slidably connected to guide and limit the translation of the longitudinal formwork 210 and the transverse formwork 220 during the formwork removal, so as to further ensure the stability of the translation of the longitudinal formwork 210 and the transverse formwork 220 during the formwork removal.

[0026] When the square pier formwork mechanism is used to construct the square pier 100 of a bridge, the following steps are performed: Step one, the operation platform 260 is erected at a predetermined position in the square pier 100 construction area to ensure that the operation platform 260 is horizontally stable, and then the integrated control center is installed at a position on the ground that is convenient for operation. The appearance and dimensional accuracy of the longitudinal formwork 210, the transverse formwork 220, the tensioning screw 240, the hoop longitudinal beam 310, and the hoop transverse beam 320 are checked to ensure that each component is undamaged and deformed, and meets the assembly requirements.

[0027] Step two, the hoop longitudinal beam 310 is aligned with the buckle 230 fixed to the back of the longitudinal formwork 210, and is slowly inserted until the buckle 230 precisely engages the hoop longitudinal beam 310 to achieve the tight connection and fixation between the hoop longitudinal beam 310 and the longitudinal formwork 210; the hoop transverse beam 320 is connected and fixed with the transverse formwork 220 in the same way, so that the hoop longitudinal beam 310 and the longitudinal formwork 210, and the hoop transverse beam 320 and the transverse formwork 220 form integral structures, respectively.

[0028] Step three, move the four templates to the outside of the square pier 100, adjust the position so that the four templates enclose the square pier 100 from four directions to form a complete wrapping structure for the square pier 100. By observing the relative position of the template edge and the square pier 100, the overall position of the template assembly is preliminarily determined to ensure that the coverage range of the template assembly matches the size of the square pier 100, laying a foundation for subsequent fastening operations.

[0029] Step four, take the tensioning screw 240, make the tensioning screw 240 pass through the pre-designed through hole on the hoop longitudinal beam 310 and the hoop transverse beam 320; the operator uses special tools to tighten the hoop, so that the tensioning screw 240 generates tension, further shortens the hoop longitudinal beam 310 and the hoop transverse beam 320, and completes the fastening work of the template assembly, providing a stable and reliable structural foundation for subsequent concrete pouring.

[0030] Step five, after the concrete pouring is completed, the intelligent monitoring system is started to monitor the strength of the concrete in real time; when the monitoring system detects that the strength of the concrete reaches the preset demolding strength, the integrated control center sends a demolding signal, and after the operator receives the demolding signal, the tensioning screw 240 is unloaded to gradually release the active constraint of the template assembly, creating conditions for subsequent demolding actions.

[0031] Step six, the operator sends a start demolding instruction through the integrated control center, and the hydraulic jack 330 installed on the hoop transverse beam 320 and the hydraulic jack 330 installed on the hoop longitudinal beam 310 are started according to the preset program in sequence, which pushes the hoop longitudinal beam 310 and the hoop transverse beam 320 in sequence, so that the two hoop longitudinal beams 310 drive the two longitudinal templates 210 and the two hoop transverse beams 320 drive the two transverse templates 220 to translate outward in sequence. During this process, the display screen of the integrated control center displays the moving speed, position and other parameters of the longitudinal template 210 and the transverse template 220 in real time for the operator to monitor in real time until the entire template assembly is completely removed.

Claims

1. Square pier column formwork mechanism, characterized by: The invention comprises a formwork assembly adapted to a square pier column (100) and composed of a longitudinal formwork (210) and a transverse formwork (220) which are detachably connected; and at least two sets of demoulding mechanisms which are spaced apart and arranged on the periphery of the formwork assembly along the height direction of the formwork assembly, the demoulding mechanisms comprising a hoop longitudinal beam (310), a hoop transverse beam (320) and a hydraulic jack (330); the two hoop longitudinal beams (310) and the two hoop transverse beams (320) are detachably connected on the periphery of the formwork assembly to form a square frame structure, the hoop longitudinal beams (310) are detachably connected to the longitudinal formwork (210), the hoop transverse beams (320) are detachably connected to the transverse formwork (220), and the hydraulic jack (330) is driven and connected between the hoop transverse beams (320) and the hoop longitudinal beams (310).

2. The square pier column formwork mechanism according to claim 1, characterized in that: A plurality of buckles (230) are fixedly provided on the outer sides of the longitudinal template (210) and the transverse template (220), and the hoop longitudinal beam (310) and the hoop transverse beam (320) are connected to the template assembly via corresponding buckles (230).

3. The square pier column formwork mechanism according to claim 1, characterized in that: It also includes a plurality of tension screws (240), and the hoop longitudinal beam (310) and the hoop transverse beam (320) are provided with through holes adapted to the tension screws (240); the hoop longitudinal beam (310) and the hoop transverse beam (320) are tightened and fixed to the template assembly via the corresponding tension screws (240).

4. The square pier column formwork mechanism according to claim 1, characterized in that: The transverse template (220) is an integrated template structure, and the longitudinal template (210) is a split template structure composed of a plurality of detachably connected template units; The plurality of template units constituting the longitudinal template (210) and the template units and the transverse template (220) are detachably connected through the cooperation of the bolt holes (250) and the bolts.

5. The square pier column formwork mechanism according to claim 1, characterized in that: It also includes an operating platform (260) arranged at the bottom of the template assembly, the operating platform (260) is provided with a square hole adapted to the square pier column (100), and the operating platform (260) is fixed to the periphery of the square pier column (100).

6. The square pier column formwork mechanism according to claim 5, characterized in that: A plurality of slide grooves (261) are fixedly provided on the operating platform (260), and the slide grooves (261) extend radially outwardly of the template assembly; the longitudinal template (210) and the transverse template (220) form a sliding fit with the slide grooves (261) via sliders fixed at the bottom.

7. The square pier column formwork mechanism according to claim 1, characterized in that: The output end of the hydraulic jack (330) is fixedly connected to a limiting block (341), and the backs of the hoop longitudinal beam (310) and the hoop cross beam (320) are both provided with limiting grooves (342) extending along their length directions; the limiting blocks (341) connected to the output end of the hydraulic jack (330) are embedded in the corresponding limiting grooves (342) to form a sliding fit.

8. The square pier column formwork mechanism according to claim 7, characterized in that: Two hydraulic jacks (330) are respectively provided on each hoop longitudinal beam (310) and each hoop transverse beam (320). The two hydraulic jacks (330) are respectively fixed to the two ends of the corresponding hoop longitudinal beam (310) or hoop transverse beam (320). The output ends of the hydraulic jacks (330) form a sliding fit with the two ends of the adjacent hoop transverse beam (320) or hoop longitudinal beam (310).

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