Construction method of pylon assembly type truss steel mold system

Abstract

The present application relates to a kind of construction methods of cable tower assembly type truss steel mould system, comprising the following steps: first installation of assembly type truss steel mould system, pouring first section cable tower unit concrete, assembly type truss outer mould turnover climbing and reinforcement cage binding synchronous construction, top inclined support removal, slot rail lengthening, assembly type truss inner mould slipform climbing construction, pouring cable tower unit.The beneficial effects of the present application are: turnover construction technology and slipform construction are organically combined to form assembly type truss steel mould system suitable for hollow cable tower, which improves the assembly and disassembly mode of cable tower inner mould in narrow space, and achieves full recovery and utilization of inner mould;Assembly type truss outer mould provides counterforce for assembly type truss inner mould slipform construction, and through lifting frame, the coordination working capacity of cable tower inner and outer mould is enhanced;The operation process does not affect the binding operation of reinforcement cage, and improves work efficiency.

Description

Technical Field

[0001] This invention is applicable to the construction of prefabricated truss steel formwork systems for cable towers, and particularly relates to a construction method for such systems. Background Technology

[0002] Bridge pylon construction often faces numerous challenges, especially the cast-in-place construction of tall hollow pylons. The biggest difficulty lies in the formwork. Formwork for hollow pylons requires the simultaneous preparation of both outer and inner formwork, ensuring their coordinated operation during construction, which is extremely challenging. Currently, the formwork method for hollow pylons often involves using a truss formwork flipping process for the outer formwork and a wooden formwork binding method for the inner formwork. Numerous tie rods connect the inner and outer formwork, and the placement and dismantling of the wooden inner formwork requires extensive manual labor. However, the construction space for the inner formwork is extremely limited, posing numerous safety hazards and impacting overall formwork efficiency.

[0003] Among the published technical documents, CN201020300284.3 discloses a truss-type waler formwork without tie rods, but it is mainly suitable for the construction of solid tower columns. When used in the construction of hollow cable towers, it cannot effectively cooperate with the inner formwork of the tower column. CN202210706759.6 discloses a self-lifting truss formwork, which achieves the joint sliding formwork construction of the outer and inner formwork of the pier by setting two pairs of guide rods on the concrete of the pier. However, since the weight difference between the inner and outer formwork is generally large, it will produce a certain eccentric effect on the pier during sliding. In addition, the setting of guide rods also greatly hinders the binding operation of the pier reinforcement cage, thus affecting the construction progress. CN202120216898.1 discloses a structure in which both the inner and outer formwork adopt the flipping operation. However, for hollow cable towers, the construction space of the inner formwork is often very small, so the probability of the inner formwork achieving flipping is almost impossible, and therefore it cannot be used in the construction of hollow cable towers.

[0004] In summary, there is an urgent need for a formwork technology that can improve the construction efficiency of the inner formwork of hollow tower columns and ensure that the coordinated operation of the inner and outer formwork does not affect the binding of the reinforcing cage. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a construction method for a prefabricated steel formwork system for cable towers.

[0006] The construction method for this type of prefabricated truss steel formwork system for cable towers includes the following steps:

[0007] Step 1: Initial installation of the prefabricated truss steel formwork system: Install the prefabricated truss inner formwork, weld rollers on the outside and lay out channel rails; perform the reinforcement cage binding operation of the tower unit and the installation of the prefabricated truss outer formwork unit around the prefabricated truss inner formwork in a cyclical manner, and install tie rods on the upper part of the prefabricated truss outer formwork.

[0008] Step 2: Pouring concrete for the first section of the cable tower unit: Pour concrete into the space formed by the inner and outer molds of the prefabricated truss to the height of the inner steel mold, thereby forming the first section of the cable tower unit.

[0009] Step 3: Simultaneous construction of prefabricated truss outer formwork flipping and climbing and rebar cage binding: The prefabricated truss outer formwork unit is flipped and reinstalled section by section from bottom to top, and the corresponding rebar cage is bound at the same time; then a tie rod is set on the upper part of the new prefabricated truss outer formwork.

[0010] Step 4: Remove the top diagonal brace and extend the channel rail: Remove the top diagonal brace, extend the channel rail, and then re-tie the top diagonal brace to the top of the channel rail.

[0011] Step 5: Slipform Climbing Construction of Prefabricated Truss Inner Formwork: Install the lifting frame and start the winch to lift the prefabricated truss inner formwork upward along the extended channel rail by the height of one inner steel formwork.

[0012] Step 6: Casting the tower unit: Casting to form a new tower unit; dismantling the lifting frame and simultaneously cutting off the tie rods at the bottom of the new prefabricated truss outer formwork.

[0013] As a preferred embodiment, in step one: first, install the inner formwork truss in the center of the foundation; then, weld the inner formwork reinforcing ribs around the inner formwork truss; then, weld the inner steel formwork onto the inner formwork reinforcing ribs; finally, weld rollers onto the outside of the inner steel formwork; the length of the inner steel formwork is equal to the length of the prefabricated truss outer formwork minus the height of one prefabricated truss outer formwork unit; the length of the inner formwork truss is equal to the exposed length of the embedded plate plus the length of the inner steel formwork; the bottom of the inner steel formwork is flush with the bottom of the inner formwork truss; and apply demolding agent or lubricant to the inner steel formwork.

[0014] Embedded plates are installed in the horizontal and vertical directions of the foundation. The embedded plates are in contact with the bottom of the outer side of the inner steel mold. Then, channel rails are welded along the height direction of the embedded plates. The channel rails include horizontal channel rails and vertical channel rails. Shear braces are installed between adjacent horizontal and vertical channel rails. Top diagonal braces are installed between adjacent horizontal and vertical channel rails. The top diagonal braces are bolted to the channel rails.

[0015] Preferably, in step one: the reinforcement cage binding and the installation of the prefabricated truss outer formwork are carried out simultaneously. First, the reinforcement cage is bound to the height of one prefabricated truss outer formwork unit. Then, the prefabricated truss outer formwork is installed. The prefabricated truss outer formwork units are placed at corresponding longitudinal and transverse positions on the pier cap. The longitudinal and transverse prefabricated truss outer formwork units at the same height form a prefabricated truss outer formwork unit. After one prefabricated truss outer formwork unit is installed, the construction platform on the prefabricated truss outer formwork unit is used to bind the reinforcement cage at the next height. The above installation steps are repeated until the reinforcement cage and prefabricated truss outer formwork corresponding to the first tower unit are completed. The height of the reinforcement cage is equal to the height of the inner steel formwork, while the total height of the prefabricated truss outer formwork is greater than the height of the reinforcement cage by the height of one prefabricated truss outer formwork unit.

[0016] Tie rods are installed between the longitudinal prefabricated truss outer formwork units corresponding to the upper part of the tower unit. The tie rods orthogonally penetrate the transverse sidewalls of the tower unit, thereby completing the first installation of the prefabricated truss steel formwork system.

[0017] Preferably, in step three: during the process of climbing and flipping the prefabricated truss outer formwork, the prefabricated truss outer formwork unit with tie rods is fixed and not dismantled. After each prefabricated truss outer formwork unit is climbed and flipped, the corresponding height of the reinforcing cage is immediately tied, thereby gradually completing the tying operation of the reinforcing cage corresponding to a tower unit. The height of the prefabricated truss outer formwork and the reinforcing cage are consistent after the flipping is completed, and the tie rods set in step one are located at the lower part of the new prefabricated truss outer formwork after the flipping is completed.

[0018] Preferably, in step five: the lifting frame includes a leg truss, a horizontal truss, and a shear brace, with a base plate fixedly installed on one side of one of the horizontal trusses; during the installation of the lifting frame, firstly, a leg truss is symmetrically installed on each side of the top middle of the prefabricated truss outer formwork and fixed with connecting bolts; then, the two horizontal trusses and one shear brace are connected together on the ground, and then the whole assembly is lifted and installed onto the two leg trusses and fixed with connecting bolts; the winch is fixed with the base plate, and then the winch is connected to the prefabricated truss inner formwork below using steel ropes, thus completing the installation of the lifting frame;

[0019] After the inner formwork of the prefabricated truss is raised into place, a demolding agent or lubricant is sprayed onto the inner steel formwork.

[0020] Preferably, in step six: the tie rods at the bottom of the new prefabricated truss outer formwork are cut off along the outer surface of the tower unit, while the remaining tie rods are still retained in the transverse sidewall of the new tower unit.

[0021] As a preferred option: repeat steps three through six until the construction of all tower units is completed.

[0022] A prefabricated truss steel formwork system for cable towers, obtained by any of the methods described above.

[0023] The beneficial effects of this invention are:

[0024] 1) Compared with the existing technology, the present invention organically combines the flip-form process with the slipform construction to form a prefabricated truss steel formwork system suitable for hollow cable towers. It improves the assembly and disassembly method of the inner formwork of the cable tower in a narrow space, achieves full recycling and utilization of the inner formwork, improves work efficiency, reduces costs, and has significant technical and economic benefits.

[0025] 2) Compared with the prior art, the prefabricated truss outer formwork of the present invention provides a reaction force for the slipform construction of the prefabricated truss inner formwork, and enhances the coordinated working ability of the inner and outer formwork of the cable tower through the lifting frame.

[0026] 3) Compared with the prior art, the prefabricated truss outer formwork flipping operation and the prefabricated truss inner formwork sliding operation of the present invention do not affect the steel cage binding operation, thus improving work efficiency and having certain technical advantages. Attached Figure Description

[0027] Figure 1 This is a cross-sectional view of the installation of the internal formwork of the prefabricated truss.

[0028] Figure 2 This is a cross-sectional view of the grooved rail installation;

[0029] Figure 3 This is a cross-sectional view of the simultaneous construction of reinforcing cage binding and prefabricated truss external formwork installation;

[0030] Figure 4 This is a cross-sectional view of the prefabricated truss outer formwork after installation.

[0031] Figure 5 This is a cross-sectional view of the prefabricated truss steel formwork system formed after the tie rods are installed;

[0032] Figure 6 This is a cross-sectional view after the concrete pouring of the first section of the tower unit was completed;

[0033] Figure 7 This is a top view after the first section of the tower unit has been poured with concrete;

[0034] Figure 8 It is a cross-sectional view of the simultaneous construction process of the prefabricated truss outer formwork flipping and climbing and the steel cage binding;

[0035] Figure 9 This is a cross-sectional view of the tie rods installed after the simultaneous construction of the prefabricated truss outer formwork flipping and climbing and the steel cage binding is completed.

[0036] Figure 10This is a cross-sectional view of the extended grooved rail;

[0037] Figure 11 This is a cross-sectional view of the lifting frame after installation;

[0038] Figure 12 This is a top view of the lifting frame after installation;

[0039] Figure 13 This is a cross-sectional view of the sliding formwork climbing construction of the prefabricated truss inner formwork;

[0040] Figure 14 It is a cross-sectional view of the new tower unit formed after the concrete pouring is completed;

[0041] Figure 15 It is a cross-sectional view of the prefabricated truss outer formwork being flipped and climbed after the lifting frame is removed and the lower tie rods are cut off;

[0042] Figure 16 This is a flowchart of the construction process for the prefabricated truss steel formwork system of the cable tower.

[0043] The diagram is labeled as follows: 1. Foundation; 2. Prefabricated truss outer formwork unit; 2-1. Connecting ear plate; 2-2. Guardrail; 2-3. Construction platform; 2-4. Outer formwork truss; 2-5. Outer formwork reinforcing rib; 2-6. Outer steel formwork; 2-7. Longitudinal prefabricated truss outer formwork unit; 2-8. Transverse prefabricated truss outer formwork unit; 3. Connecting bolt; 4. Tie rod; 4-1. Residual tie rod; 5. Lifting frame; 5-1. Horizontal truss; 5-2. Leg truss; 5-3. Base plate; 6. Tower unit; 7. Prefabricated truss inner formwork; 7-1. Inner formwork truss; 7-2. Roller; 7-3. Inner formwork reinforcing rib; 7-4. Inner steel formwork; 8. Channel rail; 8-1. Water-swellable waterstop strip; 8-2. Top diagonal brace; 9. Embedded plate; 10. Reinforcing cage; 11. Winch; 12. Steel rope; 13. Shear brace. Detailed Implementation

[0044] The present invention will be further described below with reference to embodiments. The description of the embodiments below is only for the purpose of helping to understand the present invention. It should be noted that those skilled in the art can make several modifications to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0045] Example 1

[0046] As one example, such as Figures 1 to 16 As shown, a construction method for a prefabricated truss steel formwork system for cable towers includes the following steps:

[0047] Step 1: Initial Installation of the Prefabricated Truss Steel Formwork System: The prefabricated truss steel formwork system includes the prefabricated truss inner formwork 7 and the prefabricated truss outer formwork. During the initial installation, the prefabricated truss inner formwork 7 is installed first, followed by the prefabricated truss outer formwork. The initial installation of the prefabricated truss steel formwork system also includes the installation of the channel rails 8, the reinforcing cage 10, and the tie rods 4. The specific construction steps are as follows:

[0048] 1.1 Installation of the prefabricated truss inner formwork: The prefabricated truss inner formwork 7 consists of an inner formwork truss 7-1, inner formwork reinforcing ribs 7-3, an inner steel formwork 7-4, and rollers 7-2. The inner formwork reinforcing ribs 7-3 are arranged around the inner formwork truss 7-1 and welded to the inner steel formwork 7-4 to form an integral unit. The rollers 7-2 are arranged along the vertical and circumferential directions of the inner steel formwork 7-4 at certain vertical intervals on the outside of the inner steel formwork 7-4. Each set of vertical rollers 7-2 is inserted into the grooved rail 8 for slipforming construction of the prefabricated truss inner formwork 7. The length of the inner steel formwork 7-4 is equal to that of the prefabricated truss outer formwork. The length is reduced by the height of one prefabricated truss outer formwork unit 2; the length of the inner formwork truss 7-1 is equal to the exposed length of the embedded plate 9 plus the length of the inner steel formwork 7-4; the bottom of the inner steel formwork 7-4 is flush with the bottom of the inner formwork truss 7-1. The prefabricated truss inner formwork 7 is placed in the center of the bearing platform 1 in the following order: first, install the inner formwork truss 7-1; then, weld the inner formwork reinforcing ribs 7-3 around the inner formwork truss 7-1; then, weld the inner steel formwork 7-4 on the inner formwork reinforcing ribs 7-3; and finally, weld the rollers 7-2 on the outside of the inner steel formwork 7-4. Demolding agent or lubricant is applied to the inner steel formwork 7-4.

[0049] 1.2 Installation of Channel Rail: The channel rail 8 is made of channel steel, and the length of one unit of channel rail 8 is equal to the length of the inner steel mold 7-4; the inner wall of the channel rail 8 is provided with a water-swellable waterstop strip 8-1 to prevent water leakage at the joint between the prefabricated truss inner mold 7 and the channel rail 8; before installing the channel rail 8, embedded plates 9 are first set at the corresponding positions in the transverse and longitudinal directions during the construction of the foundation 1. The embedded plates 9 are in contact with the bottom position of the outer side of the inner steel mold 7-4, and then the channel rail is welded along the height direction of the embedded plates 9. Rail 8 forms transverse and longitudinal grooved rails 8 on the pier 1. Shear bracing 13 is provided between adjacent transverse and longitudinal grooved rails 8, and top diagonal bracing 8-2 is provided between adjacent transverse and longitudinal grooved rails 8. The top diagonal bracing 8-2 is bolted to the grooved rails to facilitate the installation and removal of the top diagonal bracing 8-2. The shear bracing 13 and the top diagonal bracing 8-2 improve the overall rigidity of the transverse and longitudinal grooved rails 8, which is beneficial to the slipform construction of the prefabricated truss inner formwork 7.

[0050] 1.3 Simultaneous construction of rebar cage binding and prefabricated truss outer formwork installation: Rebar cage 10 is bound at predetermined positions around the prefabricated truss inner formwork 7. When the binding height of rebar cage 10 reaches the height of one prefabricated truss outer formwork unit 2, the prefabricated truss outer formwork is installed. After each prefabricated truss outer formwork unit 2 is installed, the corresponding rebar cage 10 is bound using the construction platform 2-3 on the prefabricated truss outer formwork unit 2. This process is repeated until the rebar cage 10 corresponding to the first tower unit 6 and the prefabricated truss outer formwork are completed. The height of rebar cage 10 is equal to the height of inner steel formwork 7-4, while the total height of prefabricated truss outer formwork is greater than the height of rebar cage 10 by the height of one prefabricated truss outer formwork unit 2. The prefabricated truss outer formwork draws on existing truss steel formwork technology and is composed of 3 to 5 prefabricated truss outer formwork units 2 connected vertically. Each prefabricated truss outer formwork unit 2 consists of an outer steel formwork 2-6, outer formwork reinforcing ribs 2-5, an outer formwork truss 2-4, a construction platform 2-3, and a guardrail 2-2. The outer steel formwork 2-6 is rigidly connected to the inner side of the outer formwork truss 2-4 via the outer formwork reinforcing ribs 2-5. The outer steel formwork 2-6 is at the same height as the outer formwork truss 2-4. The construction platform 2-3 is rigidly connected to the top outer side of the outer formwork truss 2-4, and is located on the outer side of the construction platform 2-3. Install guardrail 2-2; the top and bottom of the outer formwork truss 2-4 are provided with connecting ear plates 2-1, and connecting bolts 3 are set through the bolt holes in the connecting ear plates 2-1 to connect the prefabricated truss outer formwork units 2 to form an integral whole; the prefabricated truss outer formwork units 2 are placed in the corresponding longitudinal and transverse positions of the pier 1, thereby forming longitudinal prefabricated truss outer formwork units 2-7 and transverse prefabricated truss outer formwork units 2-8. The longitudinal and transverse prefabricated truss outer formwork units 2-8 are fixed by bolts, which facilitates the dismantling and connection during the construction of the prefabricated truss outer formwork.

[0051] 1.4 Setting the upper tie rods: Tie rods 4 are set between the longitudinal prefabricated truss outer formwork units 2-7 corresponding to the upper part of the tower unit 6. The tie rods 4 orthogonally penetrate the transverse side wall of the tower unit 6, thereby completing the first installation of the prefabricated truss steel formwork system.

[0052] Step 2: Pouring concrete for the first tower unit: Pour concrete into the space formed by the inner formwork 7 and the outer formwork of the prefabricated truss. The pouring height of the concrete is equal to the height of the inner steel formwork 7-4, thus forming a tower unit 6.

[0053] Step 3: Simultaneous Construction of Prefabricated Truss External Formwork Reversal and Reinforcing Cage Binding: Using the newly completed tower unit 6 as a foundation, and drawing on existing formwork reversal techniques, the prefabricated truss external formwork unit 2 with tie rods 4 is initially fixed without removal. The prefabricated truss external formwork unit 2 is then dismantled section by section from bottom to top using a tower crane. Through cyclical reversal and reinstallation, the reversal and climbing of the prefabricated truss external formwork is completed. During the reversal and climbing process, each time a prefabricated truss external formwork unit 2 is reversed and climbed, the corresponding reinforcing cage 10 is immediately bound, thus gradually completing the binding operation of the reinforcing cage 10 corresponding to one tower unit 6. After the reversal is completed, the height of the prefabricated truss external formwork and the reinforcing cage 10 are consistent. After the construction of the reinforcing cage 10 is completed, step 1.4 is repeated to install the upper tie rods 4.

[0054] Step 4: Remove the top diagonal brace and extend the channel rail: Before extending the channel rail 8, remove the existing top diagonal brace 8-2 of the channel rail 8, then extend the channel rail 8 by welding, and finally re-attach the previously removed top diagonal brace 8-2 to the newly extended channel rail.

[0055] Step 5, Lifting Frame Installation: Lifting frame 5 consists of two leg trusses 5-2, two horizontal trusses 5-1, and one shear brace 13. One of the horizontal trusses 5-1 has a base plate 5-3 fixedly installed on one side to facilitate the installation of the winch 11. The connection method between the leg trusses 5-2, the horizontal trusses 5-1, and the shear brace 13 is the same as the connection method between the prefabricated truss outer formwork unit 2. When installing lifting frame 5, first install one leg truss 5-2 symmetrically on each side of the top middle of the prefabricated truss outer formwork and fix it with connecting bolts 3. Then connect the two horizontal trusses 5-1 and the shear brace 13 together on the ground, and then lift and install the whole frame onto the two leg trusses 5-2 to complete the installation of lifting frame 5.

[0056] Step Six: Slipform Climbing Construction of Prefabricated Truss Inner Formwork: After the hoisting frame 5 is installed, the winch 11 is fixed by the base plate 5-3. Then, the winch 11 is connected to the prefabricated truss inner formwork 7 below by the steel rope 12. The winch 11 is started to lift the prefabricated truss inner formwork 7 upward along the extended channel rail 8 to the height of an inner steel formwork 7-4. This completes the slipform climbing construction of the prefabricated truss inner formwork 7. After the slipform is climbed to the position, demolding agent or lubricant is sprayed onto the inner steel formwork 7-4.

[0057] Step 7: Pouring concrete for the tower unit: Similar to step 2, pour concrete to form a new tower unit 6.

[0058] Step 8: Remove the lifting frame and cut off the lower tie rods: After the poured concrete has solidified and hardened, remove the lifting frame 5 and simultaneously cut off the tie rods 4 at the bottom of the prefabricated truss outer formwork along the outer surface of the tower unit 6. The remaining tie rods 4-1 in the middle are still retained in the transverse side wall of the new tower unit 6.

[0059] Repeat steps three through eight to gradually complete the climbing of the prefabricated truss steel formwork system and the construction of other cable tower units 6.

[0060] Example 2

[0061] Based on the construction method of the prefabricated truss steel formwork system for cable towers proposed in Embodiment 1, this embodiment proposes a prefabricated truss steel formwork system for cable towers, as follows: Figures 1 to 15 As shown, it includes: lifting frame 5, tower unit 6, prefabricated truss inner formwork 7 and prefabricated truss outer formwork; the prefabricated truss inner formwork 7 is located in the center of the pier 1, the steel cage 10 of the tower unit 6 is located around the prefabricated truss inner formwork 7, and the prefabricated truss outer formwork is located around the steel cage 10.

[0062] The prefabricated truss inner mold 7 includes an inner mold truss 7-1, inner mold reinforcing ribs 7-3, an inner steel mold 7-4, and rollers 7-2. The inner mold reinforcing ribs 7-3 are located around the inner mold truss 7-1 and connect to the inner steel mold 7-4. Multiple rollers 7-2 are located vertically and circumferentially on the outside of the inner steel mold 7-4, and each set of vertical rollers 7-2 is connected to a channel rail 8 on its outer side. The length of a single unit channel rail 8 is equal to the length of the inner steel mold 7-4. Water-swellable sealing strips 8-1 are provided on the inner wall of the channel rail 8. The channel rail 8 is bolted to the top diagonal brace 8-2.

[0063] The prefabricated truss outer formwork comprises several prefabricated truss outer formwork units 2. Each prefabricated truss outer formwork unit 2 includes an outer steel formwork 2-6, an outer formwork truss 2-4, and a construction platform 2-3. The top and bottom of the outer formwork truss 2-4 are equipped with connecting lugs 2-1. Vertically adjacent prefabricated truss outer formwork units 2 are also bolted together via bolt holes in the connecting lugs 2-1 and connecting bolts 3. The outer steel formwork 2-6 is rigidly connected to the inner side of the outer formwork truss 2-4 via outer formwork reinforcing ribs 2-5. The outer steel formwork 2-6 is at the same height as the outer formwork truss 2-4. The construction platform 2-3 is rigidly connected to the top outer side of the outer formwork truss 2-4. A guardrail 2-2 is provided on the outer side of the construction platform 2-3.

[0064] The prefabricated truss outer formwork unit 2 at the top of the prefabricated truss outer formwork is fixed by tie rods 4; the prefabricated truss outer formwork unit 2 also includes longitudinal prefabricated truss outer formwork unit 2-7 and transverse prefabricated truss outer formwork unit 2-8. Tie rods 4 are provided between the longitudinal prefabricated truss outer formwork units 2-7 corresponding to the top of each tower unit 6. The tie rods 4 orthogonally penetrate the transverse sidewall of the tower unit 6.

[0065] When the prefabricated truss outer formwork is flipped and climbed, the prefabricated truss outer formwork unit 2 is flipped and reinstalled section by section from bottom to top, and the corresponding steel cage 10 is tied at the same time. Then, a tie rod 4 is set on the upper part of the new prefabricated truss outer formwork to complete the flipping and climbing of the prefabricated truss outer formwork. At this time, the lifting frame 5 is set on the top of the prefabricated truss outer formwork. The lifting frame 5 includes a leg truss 5-2, a horizontal truss 5-1 and a shear brace 13. One of the horizontal trusses 5-1 has a winch 11 on one side through the base plate 5-3. Two leg trusses 5-2 are symmetrically arranged in the middle of the top of the prefabricated truss outer formwork. A horizontal truss 5-1 is set on the top of the leg truss 5-2. The horizontal trusses 5-1 on both sides are connected by the shear brace 13. The prefabricated truss outer formwork, the leg trusses 5-2, the horizontal trusses 5-1 and the shear brace 13 are connected by connecting bolts 3.

[0066] The lifting frame 5 is connected to the prefabricated truss inner formwork 7 below via a winch 11 and steel rope 12. By activating the winch 11 on the lifting frame 5, the prefabricated truss inner formwork 7 is lifted upwards along the extended channel rail 8 by the height of an inner steel formwork 7-4, thus achieving the climbing of the prefabricated truss inner formwork. This process is repeated, and concrete is poured simultaneously, thereby completing the construction of the cable tower prefabricated truss.

Claims

1. A construction method for a prefabricated truss steel formwork system for cable towers, characterized in that, Includes the following steps: Step 1: Initial installation of the prefabricated truss steel formwork system: Install the prefabricated truss inner formwork (7), weld rollers (7-2) on the outside and lay out channel rails (8); perform the binding of the steel cage (10) of the tower unit (6) and the installation of the prefabricated truss outer formwork unit (2) around the prefabricated truss inner formwork (7), and set tie rods (4) on the upper part of the prefabricated truss outer formwork; first install the inner formwork truss (7-1) in the middle of the foundation (1), and then weld the inner formwork reinforcing ribs (7-3) around the inner formwork truss (7-1). Then, weld the inner steel mold (7-4) onto the inner mold reinforcing rib (7-3), and finally weld the roller (7-2) onto the outside of the inner steel mold (7-4); the length of the inner steel mold (7-4) is equal to the length of the prefabricated truss outer mold minus the height of one prefabricated truss outer mold unit (2), the length of the inner mold truss (7-1) is equal to the exposed length of the embedded plate (9) plus the length of the inner steel mold (7-4), the bottom of the inner steel mold (7-4) is flush with the bottom of the inner mold truss (7-1); and apply demolding agent or lubricant to the inner steel mold (7-4); Embedded plates (9) are set in the transverse and longitudinal directions of the foundation (1). The embedded plates (9) are in contact with the bottom position of the outer side of the inner steel mold (7-4). Then, the channel rail (8) is welded along the height direction of the embedded plate (9). The channel rail (8) includes a transverse channel rail and a longitudinal channel rail. Shear bracing (13) is set between adjacent transverse and longitudinal channel rails (8). Top diagonal bracing (8-2) is set between adjacent transverse and longitudinal channel rails. The top diagonal bracing (8-2) is bolted to the channel rail (8). The binding of the reinforcing cage (10) and the installation of the prefabricated truss outer formwork are carried out simultaneously. First, the height of the reinforcing cage (10) is bound to the height of a prefabricated truss outer formwork unit (2). Then, the prefabricated truss outer formwork is installed. The prefabricated truss outer formwork unit (2) is placed at the corresponding longitudinal and transverse positions of the pier (1). The longitudinal prefabricated truss outer formwork unit (2-7) and the transverse prefabricated truss outer formwork unit (2-8) of the same height form the prefabricated truss outer formwork unit (2). The prefabricated truss outer formwork unit (2) also includes an outer steel formwork (2-6), an outer formwork truss (2-4), and a construction platform (2-3). The top and bottom of the outer formwork truss (2-4) are provided with connecting ear plates (2-1). The vertically adjacent prefabricated truss outer formwork units (2) are also connected by bolt holes and connecting screws in the connecting ear plates (2-1). Bolt (3) is bolted and connected; the outer steel formwork (2-6) is rigidly connected to the inner side of the outer formwork truss (2-4) through the outer formwork reinforcing rib (2-5), the outer steel formwork (2-6) is at the same height as the outer formwork truss (2-4), and the construction platform (2-3) is rigidly connected to the top of the outer side of the outer formwork truss (2-4); after installing one prefabricated truss outer formwork unit (2), the construction platform (2-3) on the prefabricated truss outer formwork unit (2) is used to carry out the binding operation of the steel cage (10) of the next height, and the above installation steps are repeated until the steel cage (10) corresponding to the first tower unit (6) and the prefabricated truss outer formwork are completed; the height of the steel cage (10) is equal to the height of the inner steel formwork (7-4), and the total height of the prefabricated truss outer formwork is more than the height of the steel cage (10) by the height of one prefabricated truss outer formwork unit (2); Tie rods (4) are installed between the longitudinal prefabricated truss outer formwork units (2-7) corresponding to the upper part of the tower unit (6). The tie rods (4) are orthogonally inserted into the transverse side wall of the tower unit (6), thereby completing the first installation of the prefabricated truss steel formwork system. Step 2: Pouring concrete for the first section of the tower unit: Pour concrete into the space formed by the inner formwork (7) and the outer formwork of the prefabricated truss to the height of the inner steel formwork (7-4), thereby forming the first section of the tower unit (6). Step 3: Simultaneous construction of the prefabricated truss outer formwork flipping and climbing and the reinforcement cage binding: The prefabricated truss outer formwork unit (2) is flipped and reinstalled section by section from bottom to top, and the corresponding reinforcement cage (10) is bound at the same time; then a tie rod (4) is set on the upper part of the new prefabricated truss outer formwork. Step 4: Remove the top diagonal brace and extend the channel rail: Remove the top diagonal brace (8-2), extend the channel rail (8), and then re-tie the top diagonal brace (8-2) to the top of the channel rail (8); Step 5: Slipform climbing construction of prefabricated truss inner formwork: Install the lifting frame (5), start the winch (11) to lift the prefabricated truss inner formwork (7) upwards along the extended channel rail (8) by the height of an inner steel formwork (7-4); Step 6: Casting the tower unit: Casting to form a new tower unit (6); dismantling the lifting frame (5), and simultaneously cutting off the tie rods (4) at the bottom of the new prefabricated truss outer formwork.

2. The construction method of the prefabricated truss steel formwork system for cable towers according to claim 1, characterized in that, In step three: During the process of the prefabricated truss outer formwork flipping and climbing, the prefabricated truss outer formwork unit (2) with tie rods (4) is fixed and not disassembled. Whenever a prefabricated truss outer formwork unit (2) is flipped and climbed, the corresponding height of the steel cage (10) is immediately tied, so as to gradually complete the tying operation of the steel cage (10) corresponding to a tower unit (6). The height of the prefabricated truss outer formwork and the steel cage (10) after the flipping is completed is consistent. The tie rods (4) set in step one are located at the lower part of the new prefabricated truss outer formwork after the flipping is completed.

3. The construction method of the prefabricated truss steel formwork system for cable towers according to claim 1, characterized in that, In step five: the lifting frame (5) includes a leg truss (5-2), a horizontal truss (5-1) and a shear brace (13). A base plate (5-3) is fixedly installed on one side of one of the horizontal trusses (5-1). When installing the lifting frame (5), firstly, a leg truss (5-2) is symmetrically installed on both sides of the top middle of the prefabricated truss outer formwork and fixed with connecting bolts (3). Then, the two horizontal trusses (5-1) and a shear brace (13) are connected together on the ground and then lifted and installed onto the two leg trusses (5-2) and fixed with connecting bolts (3). The winch (11) is fixed with the base plate (5-3) and then the winch (11) is connected to the prefabricated truss inner formwork (7) below with steel rope (12) to complete the installation of the lifting frame (5). After the inner formwork of the prefabricated truss (7) is raised into place, a demolding agent or lubricant is sprayed onto the inner steel formwork (7-4).

4. The construction method of the prefabricated truss steel formwork system for cable towers according to claim 2, characterized in that, In step six: the tie rods (4) at the bottom of the new prefabricated truss outer formwork are cut off along the outer surface of the tower unit (6), and the remaining tie rods (4-1) in the middle are still retained in the transverse sidewall of the new tower unit (6).

5. The construction method of the prefabricated truss steel formwork system for cable towers according to claim 1, characterized in that: Repeat steps three through six until all tower units (6) are completed.

Images