Creeping formwork system for hollow variable cross-section pier column and creeping formwork construction method

Abstract

The invention discloses a creeping formwork system and a creeping formwork construction method for a hollow variable-cross-section pier stud in the technical field of pier stud construction, the creeping formwork system comprises a construction climbing frame, an outer formwork and an inner formwork, the outer formwork and the inner formwork are arranged on the construction climbing frame, the outer formwork and the inner formwork each comprise a standard formwork and an adjusting formwork, and the standard formwork and the adjusting formwork are arranged on the construction climbing frame. The adjusting templates can be replaced in various models according to the shape and structure of the pier column. When the formwork is constructed, only the standard formwork needs to be kept unchanged, then the matched adjusting formwork is replaced according to the contour of the pier column section, the whole formwork can be rapidly adjusted, mounted and dismounted, the construction efficiency is improved, meanwhile, by accurately controlling the shape of the adjusting formwork, the accuracy of the whole formwork can be ensured, and the construction cost is reduced. Therefore, the flatness and the perpendicularity of a concrete structure are improved, construction errors are reduced, the consistency of the structure is ensured, the template can adapt to pier columns of different sizes and shapes, the universality and the flexibility of the template can be improved, and the template types and the complexity of stock management are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of pier construction, and in particular to a climbing formwork system and a climbing formwork construction method for a hollow variable-section pier. Background Art

[0002] When constructing piers of overhead buildings such as tall aqueducts, the climbing formwork system is currently mainly used for pouring construction. The general process is to divide the piers into multiple segments from bottom to top, use the cast lower piers as the installation basis of the construction climbing frame, install the formwork system on the construction climbing frame, pour the upper piers, and then move the construction climbing frame and formwork system upward to construct the segmental piers until the pier construction is completed. When constructing piers with equal cross-sections, it is only necessary to move the formwork upwards step by step, but for piers with variable cross-sections, especially hollow piers with variable cross-sections, it is necessary to adjust the combined shape of the formwork while moving the formwork upwards to make it fit the contour of the corresponding segment of the pier. It is difficult to complete the construction by relying solely on the climbing formwork system. The traditional formwork adjustment process requires a lot of manual operations and external lifting equipment, which is not only inefficient and costly, but also poses a great safety risk. Summary of the invention

[0003] In order to overcome the above-mentioned deficiencies in the existing hollow variable-section pier formwork construction process, the technical problem to be solved by the present invention is to provide a climbing formwork system and a climbing formwork construction method for hollow variable-section piers that can improve construction efficiency and ensure construction safety.

[0004] The technical solution adopted by the present invention to solve its technical problem is:

[0005] A climbing formwork system for a hollow variable-section pier, comprising a construction climbing frame, and an outer formwork system and an inner formwork system arranged on the construction climbing frame;

[0006] The lower end of the construction climbing frame is detachably fixed on the outer wall of the already cast pier column, and can be gradually raised along the pier column. A construction platform is provided in the middle of the construction climbing frame, and a lifting beam is provided at the upper end of the construction climbing frame.

[0007] The outer formwork system includes a rearward bracket and an outer formwork. The shape of the internal cavity enclosed by the outer formwork is the same as the outer contour of the corresponding segment of the pier column. The outer formwork includes an outer formwork standard plate and an outer formwork adjustment plate. The outer formwork adjustment plate has models of different sizes that can be replaced according to the outer contour of the corresponding segment of the pier column. The rearward bracket includes a back rod arranged on the back of the outer formwork standard plate. The lower end of the back rod is hinged to the construction platform, and a hydraulic rod is hinged between the middle of the back rod and the construction platform.

[0008] The inner mold system includes an inner mold bracket and an inner mold plate connected to the inner mold bracket through a connecting rod. The outer contour of the inner mold plate is the same as the cavity contour of the corresponding segment of the pier column. The inner mold plate includes an inner mold standard plate and an inner mold adjustment plate. The inner mold adjustment plate has models of different sizes that can be replaced according to the cavity contour of the corresponding segment of the pier column. The inner mold bracket is connected to the lifting device on the lifting beam through a lifting rope.

[0009] The outer mold standard plate, the outer mold adjustment plate, the inner mold standard plate and the inner mold adjustment plate are all composed of a steel plate and a plurality of ribs evenly spaced on one surface of the steel plate, and the length direction of the ribs is parallel to the height direction of the steel plate.

[0010] Furthermore, the outer contour of the cross-section of the pier is runway-shaped, and the cross-sectional area gradually decreases from bottom to top, the outer formwork includes two sections of outer straight segment formwork and two sections of outer arc segment formwork, the outer formwork standard plate includes outer formwork straight line standard plate and outer formwork arc line standard plate, wherein the outer straight segment formwork is composed of outer formwork straight line standard plate, the outer arc segment formwork is composed of outer formwork arc line standard plate and outer formwork adjustment plate, the outer formwork adjustment plate has different arc lengths according to the outer contour of the corresponding segment of the pier, and the plane shape after unfolding is isosceles trapezoids of different sizes.

[0011] Furthermore, the outer mold adjustment plates include four plates, which are symmetrically arranged at the four corners of the outer mold plate.

[0012] Furthermore, the cross-section of the pier cavity is two polygons symmetrically arranged along the axis of the pier, and the cross-sectional area gradually decreases from bottom to top. The polygon is a rectangle as a whole, and a curved edge matching the curved surface of the outer contour of the pier is provided on the side close to the curved surface. The inner template includes an inner straight line segment template and an inner arc segment template. The inner template standard plate includes an inner mold straight line standard plate and an inner mold arc standard plate, wherein the inner straight line segment template is composed of an inner mold straight line standard plate, and the inner arc segment template is composed of an inner mold arc standard plate and an inner mold adjustment plate. The inner mold adjustment plate has different arc lengths according to the cavity contour of the corresponding segment of the pier, and the plane shape after unfolding is an isosceles trapezoid of different sizes.

[0013] Furthermore, two inner mold adjustment plates are provided on the inner arc line segment template, and the two inner mold adjustment plates are symmetrically arranged along the central axis of the inner arc line segment template.

[0014] Furthermore, a group of inner formworks are respectively provided corresponding to the two cavities in the pier column, and the inner formwork brackets of the two groups of inner formworks are connected by tension screws, and tension screws are also provided between the inner formworks and the outer formworks for connection.

[0015] Furthermore, it also includes an external positioning ring and an external steel belt tensioning mechanism. The external positioning ring includes multiple ones, and its external contour is designed according to the external contour of the top of the corresponding segment of the pier. The upper end of the rib plate of the external formwork is provided with an external positioning block, and the external positioning ring is placed on the external positioning block. The external steel belt tensioning mechanism is wrapped around the outside of the entire external formwork to tighten the external formwork so that the lower end of the external formwork is in close contact with the side of the top of the pier that has been cast, and the external positioning block at the upper end of the external formwork is in close contact with the periphery of the external positioning ring.

[0016] Furthermore, the connecting rod of the inner mold system is a screw rod with adjustable length, and also includes an inner steel belt tensioning mechanism, which is arranged on the rib plate on the inner side of the inner arc segment template, the inner mold arc standard plate is an outer support plate, and the inner mold adjustment plate is an inner pull plate, and the steel plates on both sides of the inner mold adjustment plate are overlapped on the outer sides of the adjacent inner mold arc standard plates.

[0017] The climbing formwork construction method for a hollow variable-section pier column comprises the above-mentioned climbing formwork system for a hollow variable-section pier column, and further comprises the following steps:

[0018] Step 1: Complete the pouring construction of the foundation segment on the ground according to the pier column structure, and then install the construction climbing frame on the foundation segment;

[0019] Step 2: Install the outer formwork on the construction platform of the construction climbing frame, install the inner formwork on the top of the pier, and connect the inner formwork bracket of the inner formwork to the lifting equipment on the lifting beam through a hanging rope;

[0020] Step 3: Tie the steel bars of the next section at the top of the pier;

[0021] Step 4: According to the design size of the pier, select the appropriate outer mold adjustment plate, outer positioning ring and inner mold adjustment plate, and then use the outer steel belt tensioning mechanism to tighten the outer template to ensure that the lower end of the outer template is in close contact with the outer wall of the top of the pier, and the outer positioning block at the upper end is in close contact with the periphery of the outer positioning ring. Then adjust the position of the inner template by adjusting the length of the connecting rod, and fix it with the outer support plate and the inner pull plate to ensure that the lower end of the inner template is in close contact with the inner wall of the cavity at the top of the pier below. At the same time, use the inner steel belt tensioning mechanism to adjust the curvature of the inner template to adapt it to the cavity contour of the corresponding segment of the pier;

[0022] Step 5: Pour concrete into the space between the outer formwork and the inner formwork. When the concrete reaches a predetermined strength, release the formwork lock, and then use the rising construction climbing frame to synchronously move the outer formwork and the inner formwork upward.

[0023] Step 6: Repeat steps 3 to 5 to construct the next section of the pier until the pier construction is completed.

[0024] Furthermore, in step four, when fixing the outer formwork and the inner formwork, ensure that the overlap length between the outer formwork and the inner formwork and the pier below is not less than 30 cm; when the outer formwork is tightened with an external steel belt tensioning mechanism, an external steel belt tensioning mechanism is arranged every 60-100 cm along the height direction of the outer formwork, and an internal steel belt tensioning mechanism is arranged at the upper and lower ends and the middle part of the inner formwork.

[0025] The beneficial effects of the present invention are as follows: an outer formwork and an inner formwork are formed by a combination of a standard formwork and an adjustable formwork. During the construction process, it is only necessary to replace the adapted adjustable formwork according to the profile of the pier segment, so that the entire formwork can be quickly adjusted, installed and disassembled, thereby improving the construction efficiency. At the same time, by precisely controlling the shape of the adjustable formwork, the accuracy of the entire formwork can be ensured, thereby improving the flatness and verticality of the concrete structure, reducing construction errors, ensuring the consistency of the structure, and being able to adapt to piers of different sizes and shapes, thereby improving the versatility and flexibility of the formwork and reducing the complexity of the formwork types and inventory management. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a hollow pier column with a variable cross-section according to the present invention;

[0027] Figure 2 It is a structural schematic diagram of the construction climbing frame of the present invention;

[0028] Figure 3 It is a cross-sectional schematic diagram of the outer template and the inner template of the present invention;

[0029] Figure 4 It is a schematic diagram of the separation structure of the outer mold standard plate and the outer mold adjustment plate of the present invention;

[0030] Figure 5 It is a schematic diagram of the splicing of the outer mold standard plate and the outer mold adjustment plate of the outer mold plate of the present invention;

[0031] Figure 6 It is a structural schematic diagram of the outer positioning ring of the present invention;

[0032] Figure 7 It is a schematic diagram of the separation structure of the inner mold standard plate and the inner mold adjustment plate of the present invention;

[0033] Figure 8 It is a structural schematic diagram of the inner mold adjustment plate of the present invention;

[0034] Fig. 9 It is a schematic diagram of the inner structure of the inner mold adjustment plate of the present invention.

[0035] Marked in the figure are, 1-construction climbing frame, 2-external formwork, 3-inner formwork, 4-pier, 5-external positioning ring, 6-external steel belt tensioning mechanism, 7-inner steel belt tensioning mechanism, 11-construction platform, 12-lifting beam, 13-rearward bracket, 14-lifting rope, 21-external formwork standard plate, 22-external formwork adjustment plate, 23-external straight segment formwork, 24-external arc segment formwork, 25-external positioning block, 26-steel plate, 27-rib plate, 31-inner formwork standard plate, 32-inner formwork adjustment plate, 33-inner straight segment formwork, 34-inner arc segment formwork, 35-inner formwork bracket, 36-connecting rod, 37-tension screw, 38-support steel belt, 39-connecting bolt, 131-back rod, 132-hydraulic rod. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with the accompanying drawings.

[0037] It should be noted that if there are directional indication terms in the present invention, such as up, down, left, right, front, and back directions and orientation terms, they are for the purpose of facilitating the description of the relative position relationship between components, and are not specific to the absolute position of the related components or the position relationship between components. They are only used to explain the relative position relationship and movement of the components in a certain posture. If the specific posture changes, the directional indication will also change accordingly. If there are terms related to quantity in the present invention, such as "multiple", "multiple", "several", etc., they specifically refer to two or more.

[0038] like Figure 1-9 As shown, a climbing formwork system for a hollow variable-section pier provided by the present invention comprises a construction climbing frame 1, and an outer formwork system and an inner formwork system arranged on the construction climbing frame 1;

[0039] The construction climbing frame 1 is arranged on the outer wall of the already cast pier 4, and can be gradually raised along the pier 4. A construction platform 11 is arranged in the middle of the construction climbing frame 1, and a lifting beam 12 is arranged at the upper end of the construction climbing frame 1.

[0040] The outer formwork system includes a rearward bracket 13 and an outer formwork 2. The shape of the internal cavity enclosed by the outer formwork 2 is the same as the outer contour of the corresponding segment of the pier 4. The outer formwork 2 includes a plurality of outer formwork standard plates 21 and a plurality of outer formwork adjustment plates 22. The outer formwork adjustment plates 22 are replaceable in different sizes according to the outer contour of the corresponding segment of the pier 4. The rearward bracket 13 includes a back rod 131 arranged on the back of the outer formwork standard plate 21. The lower end of the back rod 131 is hinged to the construction platform 11. A hydraulic rod 132 is hinged between the middle of the back rod 131 and the construction platform 11.

[0041] The inner mold system includes an inner mold bracket 35 and an inner mold plate 3 connected to the inner mold bracket 35 through a connecting rod 36. The outer contour shape enclosed by the inner mold plate 3 is the same as the cavity contour of the corresponding segment of the pier 4. The inner mold plate 3 includes an inner mold standard plate 31 and an inner mold adjustment plate 32. The inner mold adjustment plate 32 has different sizes and can be replaced according to the cavity contour of the corresponding segment of the pier 4. The inner mold bracket 35 is connected to the lifting device on the lifting beam 12 through a suspension rope 14.

[0042] The outer mold standard plate 21, the outer mold adjustment plate 22, the inner mold standard plate 31 and the inner mold adjustment plate 32 are all composed of a steel plate 26 and a plurality of ribs 27 evenly spaced on one surface of the steel plate 26, and the length direction of the ribs 27 is parallel to the height direction of the steel plate 26.

[0043] Among them, the specific structure and installation method of the construction climbing frame 1 are the same as those of the existing climbing frames, and the construction climbing frame 1 is generally raised by means of hydraulics and slide rails. In the outer formwork system, adjacent templates are connected into a whole by bolts passing through the ribs 27, and then the outer formwork standard plate 21 is supported by the rearward bracket 13 to support and install the entire outer formwork 2. The rearward bracket 13 drives the back rod 131 to rotate by extending or shortening the hydraulic rod 132, so that the outer formwork 2 is close to or away from the pier 4, and the outer formwork 2 is assembled and disassembled. In the inner formwork system, adjacent templates are also connected into a whole by bolts passing through the ribs 27, and the lifting and positioning of the inner formwork 3 are achieved by the suspension rope 14 and the lifting beam 12. Compared with the traditional climbing formwork system, the present invention mainly adapts to the shape changes of the outer contour and the internal cavity of the pier by setting a standard formwork and an adjustable formwork, and both the standard formwork and the adjustable formwork adopt the same structural structure, that is, the structural form of the steel plate 26 plus the rib plate 27. Under the premise of ensuring its structural strength, the steel plate 26 can also be bent to form arc-shaped formworks with different curvatures, so as to adapt to different pier shapes. Among them, the outer formwork standard plate 21 and the inner formwork standard plate 31 have fixed sizes and specifications, can be reused, and have high interchangeability and versatility at different heights of the pier. The outer formwork adjustment plate 22 and the inner formwork adjustment plate 32 are designed in size, shape or position according to the specific needs of the pier, and can adapt to the structural needs of different sizes and shapes through a flexible adjustment mechanism. During the construction process, the formwork construction of the variable-section hollow pier can be realized by simply replacing the appropriate outer formwork adjustment plate 22 and the inner formwork adjustment plate 32 according to the shape and size of the corresponding segment of the pier.

[0044] To further illustrate the present climbing formwork system, the present invention provides an embodiment for constructing a complex pier column, wherein the pier column structure is as follows: Figure 1 As shown, the cross-sectional outer contour of the pier 4 is a runway shape, and the cross-sectional area gradually decreases from bottom to top at a certain slope ratio, while the shape remains unchanged. Figure 3As shown, the outer template 2 includes two outer straight segment templates 23 and two outer arc segment templates 24, and the outer template standard plate 21 includes an outer template straight line standard plate and an outer template arc line standard plate, wherein the outer straight segment template 23 is composed of an outer template straight line standard plate, and the outer arc segment template 24 is composed of an outer template arc line standard plate and an outer template adjustment plate 22, and the outer template adjustment plate 22 has different arc lengths according to the outer contour of the corresponding segment of the pier 4, and the plane shape after unfolding is an isosceles trapezoid of different sizes. The structure of the outer arc segment template 24 of the pier 4 unfolded from bottom to top is shown in FIG. Figure 6 As shown, the middle outer mold adjustment plate 22 gradually shrinks from bottom to top, and the other outer mold arc standard plates 21 remain unchanged, so that the length of the enclosed outer arc segment template 24 can be gradually reduced. At the same time, the two outer straight line segment templates 23 move closer to the middle, so that the cross-section of the spliced ​​outer arc segment template 24 is always semicircular after forced extrusion, and the center of the circle is located on the same vertical line, thereby obtaining a gradient arc outer contour. In order to more accurately adjust the curvature of the outer arc segment template 24, the outer mold adjustment plate 22 can be set in four pieces, which are symmetrically set at the four corners of the outer template 2, such as Figure 4 shown.

[0045] For the inner form of the pier column, Figure 3 , Figure 5 As shown, the cross section of the cavity of the pier column 4 is two polygons symmetrically arranged along the axis of the pier column 4, and the cross-sectional area gradually decreases from bottom to top. The polygon is a rectangle as a whole, wherein a side close to the arc surface of the outer contour of the pier column 4 is provided with an arc edge matching therewith, the inner template 3 includes an inner straight line segment template 33 and an inner arc segment template 34, the inner template standard plate 31 includes an inner mold straight line standard plate and an inner mold arc line standard plate, wherein the inner straight line segment template 33 is composed of an inner mold straight line standard plate, and the inner arc segment template 34 is composed of an inner mold arc line standard plate and an inner mold adjustment plate 32, the inner mold adjustment plate 32 is similar to the outer mold adjustment plate 22, and has different arc lengths according to the cavity contour of the corresponding segment of the pier column 4, and the plane shape after unfolding is an isosceles trapezoid of different sizes. The adjustment and replacement process of the inner arc segment template 34 is the same as the adjustment process of the outer arc segment template 24, which will not be repeated here. Similarly, in order to improve the smoothness of the adjusted arc, two inner mold adjustment plates 32 are provided on the inner arc segment template 34 , and the two inner mold adjustment plates 32 are symmetrically arranged along the central axis of the inner arc segment template 34 .

[0046] Since there are two independent cavities in the pier column 4, in order to facilitate the overall construction of the formwork, a group of inner formworks 3 are respectively provided in correspondence with the two cavities in the pier column 4, and the inner formwork brackets 35 of the two groups of inner formworks 3 are connected by a tension screw 37, and the inner formworks 3 are also connected to the outer formwork 2 by a tension screw 37. The tension screw 37 can connect the two groups of inner formworks 3 into a whole, which is convenient for overall lifting, and at the same time, the two groups of inner formworks 3 are connected to the outer formwork 2, which can increase the integrity and rigidity of the entire formwork system, and at the same time realize the distance adjustment between the inner formwork 3 and the outer formwork 2.

[0047] Furthermore, when adjusting the outer template 2 and the inner template 3, the lower end of the template is usually determined by overlapping with the pier below to determine the size of the template opening, but the upper end is not accurate enough to determine the opening size only by the shape of the outer template adjustment plate 22 and the inner template adjustment plate 32. Therefore, the preferred solution is:

[0048] For external mold systems, such as Figure 7 As shown, the outer form system also includes an outer positioning ring 5 and an outer steel belt tensioning mechanism 6. The outer positioning ring 5 includes multiple ones, and its outer contour is designed according to the outer contour of the top of the corresponding segment of the pier 4. The outer side of the upper end of the rib plate 27 of the outer form 2 is provided with an outer positioning block 25, and the outer positioning ring 5 is placed inside the outer positioning block 25. The outer steel belt tensioning mechanism 6 is wrapped around the outer side of the entire outer form 2, and is used to tighten the outer form 2, so that the lower end of the outer form 2 is in close contact with the top side of the already cast pier 4, and the outer positioning block 25 at the upper end of the outer form 2 is in close contact with the periphery of the outer positioning ring 5. The size of the outer positioning ring 5 needs to ensure that after the outer form 2 is tightened, the shape enclosed is the same as the outer contour of the corresponding segment of the pier. The outer steel belt tensioning mechanism 6 is mainly composed of a steel belt and bolts. End plates are provided at both ends of the steel belt, and the bolts are connected between the two end plates. The two end plates are closed by turning the bolts, thereby tightening the steel belt and tightening the outer form 2. The outer steel belt tensioning mechanism 6 can also adjust and shape the shape of the outer arc segment template 24. After replacing a different outer mold adjustment plate 22, it is labor-intensive to drive the template to deform only by the bolts connected between adjacent templates. Using the outer steel belt tensioning mechanism 6 to tighten the outer arc segment template 24 can more easily and accurately adjust the template curvature.

[0049] For the inner mold system, the inner mold system also includes an inner steel belt tensioning mechanism 7, which is arranged on the rib 27 inside the inner arc segment template 34. The connecting rod 36 of the inner mold system is a screw with adjustable length, and a plurality of connecting rods 36 are arranged at intervals along the height direction of the inner template 3, such as Figure 8 , Fig. 9As shown, in order to ensure the connection strength, a support steel plate 38 can be first arranged on the inner side of the steel plate 26 of the inner template 3 along the vertical direction, and the connecting rod 36 is connected to the support steel plate 38, and the support steel plate 38 is connected to the steel plate 26 by a connecting bolt 39. The inner mold arc standard plate is an outer support plate, and the inner mold adjustment plate 32 is an inner pull plate. The steel plates 26 on both sides of the inner mold adjustment plate 32 are overlapped on the outer side of the adjacent inner mold arc standard plate. The inner template 3 has an arc segment and a straight segment according to the shape of the cavity, and as the height increases, the cross-sectional area of ​​the cavity gradually decreases, so when the template is erected from bottom to top, the arc length and curvature of the arc segment will change and the straight segment will be shortened. This application adopts a structural form in which the outer support plate and the inner pull plate are alternately arranged to erect the inner template. The outer support plate adopts a standard plate, and the template position is determined and the angle is adjusted by the connecting rod 36. The inner pull plate adopts an adjustment plate, and the template is fixed by pulling the connecting rod 36 inward. In addition, overlapping the steel plates between adjacent templates can ensure that the templates are enclosed and formed while adapting to changes in the length and arc length of the templates. Because the shape accuracy of the cavity inside the pier is not high, the inner steel belt tensioning mechanism 7 only needs to cooperate with the inner pull plate to make each section of the template transition smoothly. The specific structure can be as follows: Fig. 9 As shown, a plurality of rotatable nuts are provided on the rib plate 27 of the inner template 3 , and the two ends of the steel belt are connected to the nuts by bolts. The steel belt is tightened by rotating the nuts, thereby realizing the curvature adjustment of the inner template 3 .

[0050] When constructing the pier, you can follow the following steps:

[0051] Step 1: Complete the pouring construction of the foundation segment on the ground according to the pier column structure, and then install the construction climbing frame 1 on the foundation segment;

[0052] Step 2: Install the outer formwork 2 on the construction platform 11 of the construction climbing frame 1, install the inner formwork 3 on the top of the pier 4, and connect the inner formwork bracket 35 of the inner formwork 3 to the lifting device on the lifting beam 12 through the lifting rope 14;

[0053] Step 3: Tie the steel bars of the next section of pier column at the top of pier column 4;

[0054] Step 4: According to the design size of the pier 4, select the appropriate outer mold adjustment plate 22, outer positioning ring 5 and inner mold adjustment plate 32, and then use the outer steel belt tensioning mechanism 6 to tighten the outer template 2 to ensure that the lower end of the outer template 2 is in close contact with the outer wall of the top of the pier 4, and the outer positioning block 25 at the upper end is in close contact with the periphery of the outer positioning ring 5. Then adjust the position of the inner template 3 by adjusting the length of the connecting rod 36, and fix it with the outer support plate and the inner pull plate to ensure that the lower end of the inner template 3 is in close contact with the inner wall of the cavity at the top of the lower pier 4. At the same time, use the inner steel belt tensioning mechanism 7 to adjust the curvature of the inner template 3 to adapt it to the cavity contour of the corresponding segment of the pier;

[0055] Step 5: pour concrete in the space between the outer formwork 2 and the inner formwork 3. After the concrete reaches a predetermined strength, release the formwork lock, and then use the rising construction climbing frame 1 to synchronously move the outer formwork 2 and the inner formwork 3 upward;

[0056] Step 6: Repeat steps 3 to 5 to construct the next segment of pier 4 until the construction of pier 4 is completed.

[0057] In step four, when fixing the outer formwork 2 and the inner formwork 3, ensure that the overlap length between the outer formwork 2 and the inner formwork 3 and the pier 4 below is not less than 30 cm; when the outer formwork 2 is tightened with the outer steel belt tensioning mechanism 6, an outer steel belt tensioning mechanism 6 is arranged at intervals of 60-100 cm along the height direction of the outer formwork 2, and an inner steel belt tensioning mechanism 7 is arranged at the upper and lower ends and the middle part of the inner formwork 3 to adjust the curvature of the inner formwork 3.

Claims

1. The climbing formwork system for hollow variable-section piers is characterized by: It comprises a construction climbing frame (1), and an outer mold system and an inner mold system arranged on the construction climbing frame (1); The construction climbing frame (1) is arranged on the outer wall of the already cast pier (4) and can be gradually raised along the pier (4). A construction platform (11) is arranged in the middle of the construction climbing frame (1), and a lifting beam (12) is arranged at the upper end of the construction climbing frame (1); The external formwork system comprises a rearward-moving bracket (13) and an external formwork (2); the shape of the internal cavity enclosed by the external formwork (2) is the same as the outer contour of the corresponding segment of the pier (4); the external formwork (2) comprises an external formwork standard plate (21) and an external formwork adjustment plate (22); the external formwork adjustment plate (22) has models of different sizes that can be replaced according to the outer contour of the corresponding segment of the pier (4); the rearward-moving bracket (13) comprises a back rod (131) arranged on the back of the external formwork standard plate (21); the lower end of the back rod (131) is hinged to the construction platform (11); and a hydraulic rod (132) is hinged between the middle of the back rod (131) and the construction platform (11); The inner mold system comprises an inner mold support (35) and an inner mold plate (3) connected to the inner mold support (35) via a connecting rod (36); the outer contour shape enclosed by the inner mold plate (3) is the same as the cavity contour of the corresponding segment of the pier column (4); the inner mold plate (3) comprises an inner mold standard plate (31) and an inner mold adjustment plate (32); the inner mold adjustment plate (32) has models of different sizes that can be replaced according to the cavity contour of the corresponding segment of the pier column (4); the inner mold support (35) is connected to the lifting device on the lifting beam (12) via a lifting rope (14); The outer mold standard plate (21), the outer mold adjustment plate (22), the inner mold standard plate (31) and the inner mold adjustment plate (32) are all composed of a steel plate (26) and a plurality of ribs (27) evenly spaced on one surface of the steel plate (26), wherein the length direction of the ribs (27) is parallel to the height direction of the steel plate (26).

2. The climbing formwork system for hollow variable-section piers according to claim 1, characterized in that: The cross-sectional outer contour of the pier column (4) is in the shape of a runway, and the cross-sectional area gradually decreases from bottom to top. The outer template (2) includes two sections of outer straight segment templates (23) and two sections of outer arc segment templates (24). The outer template standard plate (21) includes an outer template straight line standard plate and an outer template arc line standard plate, wherein the outer straight segment template (23) is composed of an outer template straight line standard plate, and the outer arc segment template (24) is composed of an outer template arc line standard plate and an outer template adjustment plate (22). The outer template adjustment plate (22) has different arc lengths according to the outer contour of the corresponding segment of the pier column (4), and the plane shape after unfolding is an isosceles trapezoid of different sizes.

3. The climbing formwork system for hollow variable-section piers according to claim 2, characterized in that: The outer mold adjustment plates (22) include four plates, which are symmetrically arranged at the four corners of the outer mold plate (2).

4. The climbing formwork system for hollow variable-section piers according to claim 2, characterized in that: The pier (4) is provided with two cavities, and the two cavities are provided with arc edges matching the arc surface of the outer contour of the pier (4) on one side thereof. The inner template (3) comprises an inner straight segment template (33) and an inner arc segment template (34). The inner template standard plate (31) comprises an inner straight line standard plate and an inner arc line standard plate, wherein the inner straight segment template (33) is composed of an inner straight line standard plate, and the inner arc line template (34) is composed of an inner arc line standard plate and an inner template adjustment plate (32). The inner template adjustment plate (32) has different arc lengths according to the cavity contour of the corresponding segment of the pier (4), and the plane shape after unfolding is an isosceles trapezoid of different sizes.

5. The climbing formwork system for hollow variable-section piers according to claim 4, characterized in that: The inner arc segment template (34) is provided with two inner mold adjustment plates (32), and the two inner mold adjustment plates (32) are symmetrically arranged along the central axis of the inner arc segment template (34).

6. The climbing formwork system for hollow variable-section piers according to claim 4, characterized in that: A group of inner formwork (3) is respectively provided in correspondence with the two cavities in the pier column (4); the inner formwork brackets (35) of the two groups of inner formwork (3) are connected by a tension screw (37); and the inner formwork (3) and the outer formwork (2) are also connected by a tension screw (37).

7. The climbing formwork system for hollow variable-section piers according to claim 4, characterized in that: It also includes an outer positioning ring (5) and an outer steel belt tensioning mechanism (6). The outer positioning ring (5) includes a plurality of rings, and its outer contour is designed according to the outer contour of the top of the corresponding segment of the pier (4). An outer positioning block (25) is provided on the outer side of the upper end of the rib plate (27) of the outer template (2). The outer positioning ring (5) is placed on the inner side of the outer positioning block (25). The outer steel belt tensioning mechanism (6) is wrapped around the outer side of the entire outer template (2) and is used to tighten the outer template (2) so that the lower end of the outer template (2) is in close contact with the top side of the already cast pier (4), and the outer positioning block (25) at the upper end of the outer template (2) is in close contact with the periphery of the outer positioning ring (5).

8. The climbing formwork system for hollow variable-section piers according to claim 7, characterized in that: It also includes an inner steel belt tensioning mechanism (7), which is arranged on the rib plate (27) on the inner side of the inner arc segment template (34), the connecting rod (36) of the inner mold system is a screw with adjustable length, the inner mold arc standard plate (312) is an outer support plate, the inner mold adjustment plate (32) is an inner pull plate, and the steel plates (26) on both sides of the inner mold adjustment plate (32) are overlapped on the outer side of the adjacent inner mold arc standard plate (312).

9. A climbing formwork construction method for hollow variable-section piers, characterized in that: The climbing formwork system for a hollow variable-section pier as claimed in claim 8 further comprises the following steps: Step 1: Complete the pouring construction of the foundation segment on the ground according to the pier column structure, and then install the construction climbing frame (1) on the foundation segment; Step 2: Install the outer formwork (2) on the construction platform (11) of the construction climbing frame (1), install the inner formwork (3) on the top of the pier (4), and connect the inner formwork bracket (35) of the inner formwork (3) to the lifting device on the lifting beam (12) through the lifting rope (14); Step 3: Tie the steel bars of the next section of the pier at the top of the pier (4); Step 4: According to the design size of the pier (4), select the appropriate outer mold adjustment plate (22), outer positioning ring (5) and inner mold adjustment plate (32), and then use the outer steel belt tensioning mechanism (6) to tighten the outer template (2) to ensure that the lower end of the outer template (2) is in close contact with the outer wall of the top of the pier (4), and the outer positioning block (25) at the upper end is in close contact with the periphery of the outer positioning ring (5). Then, adjust the position of the inner template (3) by adjusting the length of the connecting rod (36), and fix it with the outer support plate and the inner pull plate to ensure that the lower end of the inner template (3) is in close contact with the inner wall of the cavity at the top of the lower pier (4). At the same time, use the inner steel belt tensioning mechanism (7) to adjust the curvature of the inner template (3) to adapt it to the cavity contour of the corresponding segment of the pier; Step 5: pour concrete in the space between the outer formwork (2) and the inner formwork (3). After the concrete reaches a predetermined strength, release the formwork lock, and then use the construction climbing frame (1) to synchronously move the outer formwork (2) and the inner formwork (3) upward; Step 6: Repeat steps 3 to 5 to construct the next segment of the pier column (4) until the construction of the pier column (4) is completed.

10. The climbing formwork construction method for hollow variable-section piers according to claim 9, characterized in that: In step 4, when fixing the outer formwork (2) and the inner formwork (3), ensure that the overlap length between the outer formwork (2) and the inner formwork (3) and the lower pier (4) is not less than 30 cm; when the outer formwork (2) is tightened by the outer steel belt tensioning mechanism (6), an outer steel belt tensioning mechanism (6) is arranged at intervals of 60-100 cm along the height direction of the outer formwork (2), and an inner steel belt tensioning mechanism (7) is arranged at the upper and lower ends and the middle of the inner formwork (3).

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