A combined formwork structure and construction method for bidirectional variable-section rounded-corner cable tower construction

Abstract

The present invention relates to the engineering field, and in particular to a combined formwork structure and construction method for the construction of a bidirectional variable-section rounded corner cable tower. It comprises a shaped straight plate, a tapered straight plate, a rounded corner formwork, a back rib, a movable corner formwork fixed plate, a vertical screw, a diagonal tie rod and a bidirectional top-supporting fastening rod, and adopts three forms of a shaped straight plate, a tapered straight plate and a curved plate, and follows the combination form of "straight plate wrapped in curved plate". In particular, improvements are proposed for the curved plate. The contact surface between the curved plate and the shaped straight plate is designed to be polished into a chamfered form on the outside, and is connected by abutment method to reduce joint misalignment and improve the appearance quality of the circular arc chamfers at the four corners of the tower column. The variable cross-section from bottom to top is adjusted by the tapered straight plate, and is easy to install and disassemble, with moderate weight, which improves production efficiency, saves costs, ensures engineering quality, and has significant benefits and good effects.

Description

Technical Field

[0001] The invention relates to the engineering field, and in particular to a combined template structure and a construction method for constructing a bidirectional variable-section rounded-corner cable tower. Background Art

[0002] Modern bridges have developed in response to the needs of transportation functions and the progress of economy, science and technology. They are the product of the trinity of humanities, engineering technology and art through careful design and construction under the control of the laws of mechanics and aesthetics. With the rapid development of bridge engineering, the design of high bridge towers has become more and more common, and the cross-sectional styles of tower columns have also become rich and varied. However, for bidirectional variable cross-section rounded corner cable towers, what kind of template combination and what kind of template design can be used to ensure efficient and high-quality construction of bidirectional variable cross-section rounded corner cable towers is a key difficulty in the construction of bidirectional variable cross-section rounded corner cable towers. The present invention solves the problem that during the construction of bidirectional variable cross-section rounded corner cable towers, due to changes in the cross-sectional area and rounded corner design of the cable tower in the transverse and longitudinal directions of the bridge, improper template combination or improper rounded corner template design causes concrete misalignment, affecting the cable tower In order to solve the problems of construction progress and appearance quality, three forms of fixed straight plates, tapered straight plates and arc plates are adopted, following the combination form of "straight plates wrapped in arc plates", and special improvements are made to the arc plates. The contact surface between the arc plates and the fixed straight plates is designed to be chamfered on the outside, and the abutment method is used to connect them, which reduces the misalignment of joints and improves the appearance quality of the circular arc chamfers at the four corners of the tower column. The variable cross-section from bottom to top is adjusted by the tapered straight plates, which are easy to install and disassemble, have moderate weight, improve production efficiency, save costs, ensure project quality, and have significant benefits and good effects. Summary of the invention

[0003] Purpose of the invention: To provide a combined formwork structure and construction method for the construction of a bidirectional variable-section rounded cable tower with better effects. The specific purpose can be seen in the multiple substantial technical effects of the specific implementation part.

[0004] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0005] A combined formwork structure for the construction of a bidirectional variable-section rounded-corner cable tower, characterized in that the structure comprises a shaped straight plate 1, a tapered straight plate 2, an arc corner formwork 3, a back rib 4, a movable corner formwork fixing plate 5, a vertical screw 6, an inclined tie rod 7 and a bidirectional top-supporting fastening rod 8; the shaped straight plate 1 is spliced ​​with the tapered straight plate 2, the shaped straight plate 1 and the tapered straight plate 2 are fixed on the outside by the back rib 4, the back rib 4 on the adjacent two sides is fixed by the inclined tie rod 7, the right-angled inner sides of the tapered straight plates 2 on the adjacent two sides are abutted against the arc corner formwork 3, and the outer side of the arc corner formwork 3 is fixed to the tapered straight plate 2. The sides are polished into chamfered shapes, and the upper and lower ends of the arc corner template 3 are connected to the movable corner template fixing plate 5 by vertical screws 6. Another vertical screw 6 is arranged at the tail end of the movable corner template fixing plate, and a two-way supporting fastening rod 8 is arranged between the diagonal rod 7 and the vertical screw 6 at the tail end of the movable corner template fixing plate 5. With the diagonal rod 7 as support, the movable corner template fixing plate 5 and the vertical screw 6 at the tail end are tightened outwards through the two-way supporting fastening rod 8 to ensure that the arc corner template 3 is close to the inner surfaces of the diverging straight plates 2 on both sides, with a firm connection and close contact.

[0006] A further technical solution of the present invention is that a shaped straight plate is spliced ​​with a tapered straight plate, the shaped straight plate is a shaped steel template, the tapered straight plate is an adjustable steel template, and the variable cross-section from bottom to top is adjusted by the tapered straight plate with varying width, that is, a plurality of tapered straight plates with inconsistent widths are arranged from bottom to top, and the shaped straight plate and the tapered straight plate are fixed on the outer sides with back ribs, and the back ribs on adjacent sides are fixed with diagonal rods.

[0007] A further technical solution of the present invention is that one side of the bidirectional top-supporting fastening rod includes a groove, which can squeeze the top of the vertical screw 6 at the tail end; the other side of the bidirectional top-supporting fastening rod squeezes the diagonal rod 7 through the groove; the bidirectional top-supporting fastening rod is two screws that are threadedly nested with each other.

[0008] A further technical solution of the present invention is that the shaped straight plate and the tapered straight plate are both steel templates, the arc corner template adopts a steel template with R=200mm, and the top, middle and bottom of the arc corner template are all provided with perforated connecting plates with a hole diameter D=28mm.

[0009] A further technical solution of the present invention is that the shaped straight plate and the tapered straight plate are bolted together.

[0010] A further technical solution of the present invention is that the diameter of the diagonal tie rod is 25 mm.

[0011] A combined formwork construction method for bidirectional variable cross-section rounded corner cable tower construction, characterized in that it comprises the following steps:

[0012] 1. Determination of the formwork combination: According to the cross-sectional changes of the cable towers in the transverse and longitudinal directions and the rounded corner design of R=200mm, the arc corner formwork is separated and connected to the straight formwork by the abutment method, changing the previous design concept of "bolting" the arc corner formwork and the straight formwork flange. The customized large steel formwork is split into three unit forms: fixed straight plate, tapered straight plate, and arc corner formwork. The combination design of straight plate wrapped arc plate is adopted to ensure that the arc plate is close to the inner surface of the tapered plate, with a firm connection and close contact. Then, the contact surface between the arc corner formwork and the tapered straight plate is improved, and the outer side of the arc corner formwork is designed to be polished into a chamfered form to reduce the misalignment at the joint and improve the appearance quality of the arc corners at the four corners of the tower column. The variable cross-section from bottom to top is adjusted by the tapered straight plate with varying width;

[0013] 2. Splicing of fixed straight board and tapered straight board: The fixed straight board is a fixed steel template, and the tapered straight board is an adjustable steel template. The variable cross-section from bottom to top is adjusted by the tapered straight board with variable width. The outer side is fixed with back ribs, and the back ribs on the adjacent two sides are fixed with diagonal rods.

[0014] 3. Making and connecting the arc corner template: The inner side of the right angle of the adjacent two straight plates is connected to the arc corner template. The arc corner template is a standard steel template. The outer side of the arc corner template is ground into a chamfer. It follows the combination form of the straight plate wrapped in the arc plate and is connected by the abutment method to reduce the misalignment at the joint.

[0015] 4. Installation of arc corner formwork structure system: The upper and lower ends of the arc corner formwork are connected to the movable corner formwork fixing plate with vertical screws, and the tail end of the movable corner formwork fixing plate is provided with a vertical screw, which together form the arc corner formwork structure system;

[0016] 5. Fixing of the arc corner formwork: A two-way supporting fastening rod is set between the diagonal rod and the vertical screw at the tail end of the movable angle formwork fixed plate. With the diagonal rod as support, the vertical screw at the tail end of the movable angle formwork fixed plate is pushed outwards through the two-way supporting fastening rod to ensure that the arc corner formwork is close to the inner surface of the straight plates on both sides, with firm connection and close contact.

[0017] The present invention adopting the above technical scheme has the following beneficial effects compared with the prior art: the combined template structure and construction method are used for the construction of bidirectional variable cross-section rounded corner cable towers. The present invention solves the problem that during the construction of bidirectional variable cross-section rounded corner cable towers, due to the changes in the cross-section of the cable towers in the transverse and longitudinal directions and the rounded corner design, the improper combination of templates or the improper design of the rounded corner templates causes the concrete to be misaligned, which affects the construction progress and appearance quality of the cable towers. The present invention adopts three forms of fixed straight plates, tapered straight plates, and arc plates, and follows the combination form of "straight plates wrapped in arc plates". In particular, improvements are proposed for the arc plates. The contact surface between the arc plates and the fixed straight plates is designed to be polished into a chamfered form on the outside, and the connection is made by the abutment method to reduce the misalignment of the joints and improve the appearance quality of the rounded corners of the tower columns. The variable cross-section from bottom to top is adjusted by the tapered straight plates. It is easy to install and disassemble, has a moderate weight, improves production efficiency, saves costs, ensures engineering quality, has significant benefits, and has good effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to further illustrate the present invention, the following is further described in conjunction with the accompanying drawings:

[0019] Figure 1 It is a schematic diagram of the structure plane of the present invention;

[0020] Figure 2 It is a plan view of the arc angle template structure system of the present invention;

[0021] Among them: 1. shaped straight plate; 2. tapered straight plate; 3. arc corner template; 4. back rib; 5. movable corner template fixing plate; 6. vertical screw rod; 7. diagonal tie rod; 8. two-way top supporting fastening rod. DETAILED DESCRIPTION

[0022] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "top", "bottom", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific circumstances.

[0023] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0024] This patent provides a variety of parallel solutions. The different expressions are improved solutions or parallel solutions based on the basic solution. Each solution has its own unique characteristics. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. The fixing method not described in the text can be any fixing method such as thread fixing, bolt fixing or glue bonding.

[0025] Option 1:

[0026] A combined formwork structure and construction method for the construction of a bidirectional variable-section rounded corner cable tower, characterized in that it comprises a shaped straight plate 1, a tapered straight plate 2, an arc corner formwork 3, a back rib 4, a movable corner formwork fixing plate 5, a vertical screw 6, a diagonal tie rod 7 and a bidirectional top-supporting fastening rod 8, wherein the shaped straight plate 1 is spliced ​​with the tapered straight plate 2, the outer side is fixed with the back rib 4, the back ribs 4 on the adjacent two sides are fixed with the diagonal tie rod 7, the right-angled inner sides of the tapered straight plates 2 on the adjacent two sides are abutted against the arc corner formwork 3, and the outer side of the arc corner formwork 3 is polished into a chamfered shape. In order to reduce the misalignment at the joint, the upper and lower ends of the arc corner formwork 3 are connected to the movable corner formwork fixing plate 5 by vertical screws 6, and the vertical screw 6 is arranged at the tail end of the movable corner formwork fixing plate. A two-way supporting fastening rod 8 is arranged between the diagonal rod 7 and the vertical screw 6 at the tail end of the movable corner formwork fixing plate 5. With the diagonal rod 7 as the support, the vertical screw 6 at the tail end of the movable corner formwork fixing plate 5 is pushed outward by the two-way supporting fastening rod 8 to ensure that the arc corner formwork 3 is close to the inner surface of the straight plates 2 on both sides, with a firm connection and close contact.

[0027] As a further preference, the shaped straight board 1 is spliced ​​with the tapering straight board 2, the shaped straight board 1 is a shaped steel template, the tapering straight board 2 is an adjustable steel template, the variable cross-section from bottom to top is adjusted by the tapering straight board 2 with varying width, the outer side is fixed with back ribs 4, and the back ribs 4 on adjacent sides are fixed with diagonal rods 7.

[0028] As a further preference, the inner sides of the right angles of the adjacent two-side tapered straight plates 2 are abutted against the arc corner template 3, the arc corner template 3 is a standardized steel template, the outer sides of the arc corner template 3 are polished into chamfers, following the combination form of straight plates wrapped in arc plates, and are connected by abutment method to reduce misalignment at the joints.

[0029] As a further preference, the upper and lower ends of the arc corner template 3 are connected to the movable corner template fixing plate 5 by vertical screws 6, and a vertical screw 6 is arranged at the tail end of the movable corner template fixing plate, together forming the structural system of the arc corner template 3.

[0030] As a further preferred embodiment, a two-way supporting fastening rod 8 is provided between the diagonal tie rod 7 and the vertical screw rod 6 at the tail end of the movable corner mold fixing plate 5, and the vertical screw rod 6 at the tail end of the movable corner mold fixing plate 5 is supported by the diagonal tie rod 7 and pushed outward by the two-way supporting fastening rod 8 to ensure that the arc corner mold plate 3 is closely attached to the inner surface of the two side diverging straight plates 2, with a firm connection and close contact. Solution 2:

[0031] A combined formwork structure and construction method for bidirectional variable cross-section rounded corner cable tower construction, characterized in that it comprises the following steps:

[0032] 1. Determination of the form of template combination: According to the cross-sectional changes of the cable towers in the transverse and longitudinal directions of the bridge and the rounded corner design of R=200mm, the arc corner template is separated and connected to the straight template by the abutment method, changing the previous design concept of "bolting" the arc corner template and the straight template flange. The customized large steel template is split into three unit forms: fixed straight plate, tapered straight plate, and arc corner template. The combination design of straight plate wrapped arc plate is adopted to ensure that the arc plate is close to the inner surface of the tapered plate, with a firm connection and close contact. Then the contact surface between the arc corner template and the tapered straight plate is improved, and the outer side of the arc corner template is designed to be polished into a chamfered form to reduce the misalignment at the joint and improve the appearance quality of the arc corners of the four corners of the tower column. The variable cross-section from bottom to top is adjusted by the tapered straight plate with changing width.

[0033] 2. Splicing of fixed straight boards and tapered straight boards: The fixed straight boards are spliced ​​with tapered straight boards. The fixed straight boards are fixed steel templates, and the tapered straight boards are adjustable steel templates. The variable cross-section from bottom to top is adjusted by the tapered straight boards with changing width. The outer side is fixed with back ribs, and the adjacent back ribs are fixed with diagonal rods.

[0034] 3. Production of arc corner templates and connection by abutment method: The inner side of the right angles of the adjacent straight plates are abutted against the arc corner templates. The arc corner templates are standardized steel templates. The outer side of the arc corner templates is polished into chamfers. It follows the combination form of straight plates wrapped in arc plates and is connected by abutment method to reduce misalignment at the joints.

[0035] 4. Installation of arc corner formwork structure system: The upper and lower ends of the arc corner formwork are connected to the movable corner formwork fixing plate by vertical screws, and the tail end of the movable corner formwork fixing plate is provided with a vertical screw, which together form the arc corner formwork structure system. The arc corner formwork includes a fixing block, which is fixed by a fixing block and a vertical bolt. As a further preferred embodiment, the arc corner formwork and the movable corner formwork fixing plate can be manufactured in an integrated manner.

[0036] 5. Fixing of the arc corner formwork: A two-way supporting fastening rod is set between the diagonal rod and the vertical screw at the tail end of the movable angle formwork fixed plate. With the diagonal rod as support, the vertical screw at the tail end of the movable angle formwork fixed plate is pushed outwards through the two-way supporting fastening rod to ensure that the arc corner formwork is close to the inner surface of the straight plates on both sides, with firm connection and close contact.

[0037] As a further preference, the shaped straight plate and the tapered straight plate are both steel templates, the arc corner template adopts a steel template with R=200mm, and the top, middle and bottom of the arc corner template are all provided with perforated connecting plates with a hole diameter D=28mm.

[0038] As a further preference, the shaped straight plate and the diverging straight plate are bolted together, and the variable cross-section from bottom to top is adjusted by the diverging straight plate with varying width.

[0039] As a further preference, the outer side of the arc corner template is polished into a chamfer. Since the arc corner template has a certain thickness, misalignment will occur when it is directly abutted against the tapered straight plate. The contact surface between the arc corner template and the tapered straight plate needs to be polished into a chamfer so that the initial contact surface thickness of the arc corner template and the tapered straight plate is zero. The combination form of straight plate wrapped in arc plate is followed and the abutment method is used for connection to reduce misalignment at the joints.

[0040] As a further preference, the arc corner formwork structure system needs to be supported by diagonal tie rods with a diameter of 25 mm. The vertical screw at the tail end of the movable corner formwork fixed plate is pushed outward by a two-way top-supporting fastening rod, so that the arc corner formwork structure system is closely connected with the tapered straight plate.

[0041] The present invention is groundbreaking in that each of the above effects exists independently, and a set of structures can be used to achieve the combination of the above construction results.

[0042] The combined template structure and construction method are used for the construction of bidirectional variable cross-section rounded corner cable towers. The invention solves the problem that during the construction of bidirectional variable cross-section rounded corner cable towers, due to the changes in the cross-section of the cable towers in the transverse and longitudinal directions and the rounded corner design, the improper combination of templates or the improper design of the rounded corner templates causes the concrete to be misaligned, which affects the construction progress and appearance quality of the cable towers. The invention adopts three forms of fixed straight plates, tapered straight plates, and arc plates, and follows the combination form of "straight plates wrapped in arc plates". In particular, improvements are proposed for the arc plates. The contact surface between the arc plates and the fixed straight plates is designed to be polished into a chamfered form on the outside, and the connection is made by the abutment method to reduce the misalignment of the joints and improve the appearance quality of the rounded corners of the tower columns. The variable cross-section from bottom to top is adjusted by the tapered straight plates. It is easy to install and disassemble, has a moderate weight, improves production efficiency, saves costs, ensures engineering quality, and has significant benefits and good effects.

[0043] The basic principle, main features and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the protection required.

Claims

1. A combined formwork structure for the construction of a bidirectional variable cross-section rounded cable tower, characterized in that: The structure comprises a shaped straight plate (1), a tapered straight plate (2), an arc corner template (3), a back rib (4), a movable corner template fixing plate (5), a vertical screw (6), an inclined tie rod (7) and a bidirectional top-supporting fastening rod (8); the shaped straight plate (1) and the tapered straight plate (2) are spliced, the shaped straight plate (1) and the tapered straight plate (2) are fixed on the outside by the back rib (4), the back ribs (4) on the adjacent two sides are fixed by the inclined tie rod (7), the right-angled inner sides of the tapered straight plates (2) on the adjacent two sides are abutted against the arc corner template (3), and the outer side of the arc corner template (3) is polished into a chamfered form. The upper and lower ends of the arc corner template (3) are connected to the movable corner template fixing plate (5) by means of vertical screw rods (6), another vertical screw rod (6) is arranged at the rear end of the movable corner template fixing plate, and a bidirectional top-supporting fastening rod (8) is arranged between the inclined tie rod (7) and the vertical screw rod (6) at the rear end of the movable corner template fixing plate (5). The movable corner template fixing plate (5) and the vertical screw rod (6) at the rear end are pressed outwardly by the bidirectional top-supporting fastening rod (8) with the inclined tie rod (7) as support, so as to ensure that the arc corner template (3) is closely attached to the inner surfaces of the two-side diverging straight plates (2), and the connection is firm and the contact is tight.

2. A combined formwork structure for construction of a bidirectional variable cross-section rounded corner cable tower as claimed in claim 1, characterized in that: The fixed straight board is spliced ​​with the tapered straight board. The fixed straight board is a fixed steel template, and the tapered straight board is an adjustable steel template. The variable cross-section from bottom to top is adjusted by the tapered straight board with varying width, that is, multiple tapered straight boards with inconsistent widths are arranged from bottom to top. The fixed straight board and the tapered straight board are fixed on the outside with back ribs, and the back ribs on adjacent sides are fixed with diagonal rods.

3. A combined formwork structure for construction of a bidirectional variable cross-section rounded corner cable tower as claimed in claim 1, characterized in that: One side of the bidirectional top-supporting fastening rod comprises a groove, which can squeeze the top of the vertical screw rod (6) at the tail end; the other side of the bidirectional top-supporting fastening rod squeezes the diagonal rod (7) through the groove; the bidirectional top-supporting fastening rod is two screw rods whose threads are nested with each other.

4. A combined formwork structure for construction of a bidirectional variable cross-section rounded corner cable tower as claimed in claim 1, characterized in that: The shaped straight plate and the tapered straight plate are both steel templates, and the arc corner template adopts a steel template with R=200mm. The top, middle and bottom of the arc corner template are all provided with connecting plates with holes, and the hole diameter D=28mm.

5. The combined formwork structure for construction of a bidirectional variable cross-section rounded corner cable tower according to claim 1, characterized in that: The shaped straight plate and the tapered straight plate are bolted together.

6. A combined formwork structure for construction of a bidirectional variable cross-section rounded corner cable tower as claimed in claim 1, characterized in that: The diameter of the diagonal tie rod is 25mm.

7. A combined formwork construction method for bidirectional variable cross-section rounded corner cable tower construction, characterized in that: The following steps are involved: (1) Determination of the formwork combination: According to the cross-sectional changes of the cable towers in the transverse and longitudinal directions and the rounded corner design of R = 200 mm, the rounded corner formwork is separated and connected to the straight formwork by the abutment method, changing the previous design concept of "bolting" the rounded corner formwork and the straight formwork flange. That is, the customized large steel formwork is divided into three unit forms: fixed straight plate, tapered straight plate, and rounded corner formwork. The combination design of straight plate wrapped with arc plate is adopted to ensure that the rounded plate is close to the inner surface of the tapered plate, with a firm connection and close contact. Then, the contact surface between the rounded corner formwork and the tapered straight plate is improved. The outer side of the rounded corner formwork is designed to be chamfered to reduce the misalignment at the joint and improve the appearance quality of the rounded corners of the four corners of the tower column. The variable cross-section from bottom to top is adjusted by the tapered straight plate with varying width; (2) Splicing of fixed straight board and tapered straight board: The fixed straight board is a fixed steel template, and the tapered straight board is an adjustable steel template. The variable cross-section from bottom to top is adjusted by the tapered straight board with variable width. The outer side is fixed with back ribs, and the back ribs on the adjacent sides are fixed with diagonal rods; (3) Production of arc corner templates and connection by abutment: The inner side of the right angle of the adjacent two straight plates is abutted against the arc corner template. The arc corner template is a standard steel template. The outer side of the arc corner template is ground into a chamfer. It follows the combination form of straight plate wrapped with arc plate and is connected by abutment to reduce misalignment at the joint. (4) Installation of the arc corner formwork structure system: The upper and lower ends of the arc corner formwork are connected to the movable corner formwork fixing plate with vertical screws, and a vertical screw is set at the tail end of the movable corner formwork fixing plate, which together form the arc corner formwork structure system; (5) Fixing of the arc corner formwork: A two-way top-supporting fastening rod is arranged between the diagonal rod and the vertical screw rod at the tail end of the movable corner formwork fixing plate. With the diagonal rod as support, the vertical screw rod at the tail end of the movable corner formwork fixing plate is pushed outward by the two-way top-supporting fastening rod to ensure that the arc corner formwork is close to the inner surface of the straight plates on both sides, with a firm connection and close contact.

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