Variable cross-section high pier column lifting frame reverse mold structure suitable for rapid construction

Abstract

According to the variable cross-section high pier column lifting frame reverse formwork structure suitable for rapid construction, the operation platform, the lateral support and the formwork system are separated, and structural separation and function recombination are conducted on the basis of a traditional formwork; the slope of the formwork is preset, a flange and a long round hole are arranged on the edge of the wide formwork, continuous slope collection is achieved in the climbing process through a chain block, and meanwhile synchronous removal of an invalid formwork formed after section contraction is achieved. The lifting system bears the load of the working face of the operation platform, the weight of the formworks is borne by the pier columns, the two layers of formworks are cyclically overturned in the enclosure and the platform, the influence of the age of concrete is small, the overall construction progress is fast, opposite pull rods in the traditional technology are omitted through lateral supporting of the enclosure truss, the concrete appearance quality is good, and the structure is reliable and easy and convenient to operate. According to the utility model, the lifting of the variable cross-section thin-wall pier template outer frame and the circulating operation of reversing the template are realized, and the construction efficiency and the safety are greatly improved. According to the technology, high-quality, continuous and efficient construction of the variable-cross-section thin-wall pier of the bridge can be achieved.

Description

Technical Field

[0001] This utility model belongs to the field of bridge pier construction, specifically relating to a variable cross-section high pier lifting frame inverted formwork structure suitable for rapid construction. Background Technology

[0002] With the rapid development of highway construction, bridge projects crossing large rivers, canyons, and other terrain obstacles require the use of high pier construction methods to support the bridge structure, with pier heights often exceeding 40 meters. High pier construction methods have become a key factor in ensuring bridge safety, stability, and economy. Addressing the critical issues in high pier design and construction, advanced construction methods and strict construction procedures can significantly improve the safety and durability of high pier construction. Among these, variable cross-section high bridge sections are the most common substructure form in mountainous highways and general roads, especially when the bridges are relatively high. The large spatial cross-sectional deformation of the high pier columns in the height direction makes steel formwork unusable, and precise control is difficult in actual construction. Even slight deviations can lead to the accumulation of construction errors in the high pier columns, affecting their aesthetic appearance. Typically, strong reinforcement is required to ensure the overall rigidity of the formwork system, and the combined steel formwork has a small area, many joints, and an unsightly appearance. Common construction methods are slow and time-consuming. Currently, the formwork construction method used for high piers carries significant safety risks. The large workload of formwork installation, dismantling, and hoisting leads to low construction efficiency. Construction speed is limited by the age of the concrete, with the average speed rarely exceeding 1 meter per day. Slipforming results in poor pier appearance and reduced durability. Although roller formwork and suspended formwork technologies have been developed in recent years, these are only partial improvements to different formwork techniques, and the application of new plastic materials in pier formwork is extremely limited. Bridge construction, especially high pier construction, faces constraints such as short construction periods and large scale. An efficient and safe construction method is urgently needed to address this challenge. Utility Model Content

[0003] The purpose of this invention is to provide a high-efficiency inverted formwork structure for thin-walled bridge piers with variable cross-sections. Using this structure, rapid and efficient construction of hollow piers with uniform cross-sections can be achieved, greatly reducing the impact of concrete age on construction efficiency, while ensuring the construction quality and safety of the pier columns.

[0004] This utility model is achieved through the following technical solution: a variable cross-section thin-walled pier lifting frame inverted formwork structure, including an upper operating platform, a lower operating platform, a surrounding truss structure, a closed guardrail, a hanging frame, an outer formwork, an inner formwork, an outer formwork lifting system, an inner formwork lifting system, and a maintenance platform. The surrounding truss structure is formed by connecting four trusses in sequence with high-strength bolts to form a rectangular truss surrounding the pier column. The closed guardrail is directly connected to the surrounding truss structure with high-strength bolts. The upper operating platform is set on the surrounding truss structure. The hanging frame is bolted to the lower part of the surrounding truss structure. The lower operating platform is set at the bottom of the hanging frame. The maintenance platform is set at the bottom of the hanging frame. The lowest end of the hanging frame is equipped with a support roller that can roll upward along the pier column. Several holes are opened on the outer side of the hanging frame on the lower operating platform and the maintenance platform, and steel bars are inserted into the holes. The surrounding truss structure is connected to the outer formwork by bolt support.

[0005] The external formwork lifting system includes an external formwork lifting frame, supporting steel pipes, and wedge jacks. The external formwork lifting frame is connected to the surrounding truss structure by bolts, and the external formwork lifting frame is connected to the supporting steel pipes inserted into the concrete by wedge jacks.

[0006] The inner formwork lifting system includes an inner formwork lifting frame, supporting steel pipes, and wedge jacks. The inner formwork lifting frame is connected to the supporting steel pipes inserted into the concrete through the wedge jacks, and the inner formwork lifting frame is connected to the inner formwork crossbeam through high-strength bolts.

[0007] Furthermore, the encircling truss structure is composed of 100*10 equilateral angle steel as chord members and 63*63*6 angle steel as web members, forming a truss cross-section with an outer contour of 1.2m*1.3m. The enclosed guardrail is made of 50*50*5 steel pipe, and the upper operating platform is a 2.5mm patterned steel plate laid on the encircling truss structure. The bolt top support is made of φ28 precision rolled threaded steel, with a channel-shaped top support welded to the end to tighten the outer template beam, and the tail end supported by a nut on the perforated steel section of the encircling truss structure.

[0008] Furthermore, the bracket is made of 80*6 equilateral angle steel with a length of 4.8m. At the lower 2.8m of the bracket, a 50*5 double angle steel crossbeam is installed and a 2.5mm checkered plate is laid to form a lower operating platform. The bottom of the bracket is also made of 50*5 double angle steel crossbeam and a 2.5mm checkered plate is laid to form a maintenance platform. Holes are opened every 60cm on the outer side of the bracket on the two platforms.

[0009] Furthermore, the outer formwork is a monolithic large steel formwork with a height of 2.25m and a thickness of 5mm. The four corners are rounded. The large surface consists of two 2.95m wide steel formworks, and the small surface consists of a 2.9m wide steel formwork assembled with the rounded formworks. There are a total of two sets of outer formwork, comprising 20 pieces. Each formwork piece has a smooth, flat vertical surface. The vertical back ribs are made of No. 5 channel steel spaced 30cm apart. Angle steel is welded around the perimeter of the formwork and holes are drilled for bolt connections between the formwork pieces. The two ends of the back ribs are firmly welded to the angle steel. A formwork beam formed by two No. 14 channel steels is installed at 1 / 5 of the way in from both ends of the back ribs. After the formwork is installed, it is tightened by bolt supports. There are two sets of outer formwork. One set is installed first, and after concrete pouring, the other set is installed and concrete is poured. Subsequently, the lower set of outer formwork is disassembled piece by piece and lifted to the upper part by a tower crane for reinstallation. Throughout the construction process, both sets of outer formwork are used. The formwork is continuously disassembled and reassembled from bottom to top in a cyclical manner. The outer formwork slope is finished by clamping the large formwork with small formwork panels. Flanges and oblong holes are set at the ends of the large formwork panels. The corresponding small formwork panels are perpendicular to the large formwork panels and have bolt holes spaced 120-140mm apart. High-strength bolts are used to connect the small formwork panels to the oblong holes of the outer formwork panels. In the first cycle of the outer formwork, the operating platform is raised to a cumulative height of 4.8m and the remaining steel reinforcement is tied. At the same time, the internal formwork system is installed and the slope of the inner formwork is adjusted. After the formwork is checked, concrete can be poured. Once the concrete has initially set, the bolt supports can be removed, creating a space for formwork transport between the truss and the formwork. At this time, the lower formwork is removed for the first time and installed on top, fixed with bolt supports. As the inner formwork is raised with the pouring, a new thin-walled pouring space is formed. Subsequently, when the lower space reaches the installation height, the suspended platform can be installed.

[0010] The inner template is designed according to the cross-sectional outline of the thin-walled pier. It uses 5mm steel plates as the panel with a height of 2.25m. The vertical back ribs are made of No. 5 channel steel spaced 30cm apart. Angle steel is welded to the top and bottom edges for locking. All the division and connection of the template blocks are in the plane. Double No. 14 channel steel is set at the 1 / 5 position inward from both ends of the vertical back ribs of the inner template as template beams. The large template is set into 2 modules with 4 supports facing each other. The end corner template is divided into 3 modules, and the template can only be connected to the template outside the corner. Lateral supports are set on the template beams and connected to the nearest support to form a skeleton. When in use, bamboo plywood can be laid on it after all supports are connected to form the operating platform of the inner template.

[0011] Furthermore, the outer formwork lifting frame consists of two I18 channel steels welded together to form a rectangular cross-section vertical bar. The horizontal bar consists of two I18 channel steels back-to-back, spaced 50mm-60mm apart, connected by a gusset plate to form a lattice truss. I100 channel steel is used as a diagonal brace above and connected to the vertical bar. The installed outer formwork lifting frame is connected as a whole by the truss welded by the channel steel gusset plates. Four holes are drilled in the welded steel plate on the horizontal bar of the outer formwork lifting frame to serve as a base. Wedge jacks are placed on the base, and the supporting steel pipe is a φ48*3.5 seamless steel pipe.

[0012] Furthermore, the inner formwork lifting frame consists of two I18 channel steel supports welded together to form a rectangular cross-section vertical bar. The horizontal bar consists of two I18 channel steels back to back, spaced 50mm-60mm apart, connected by a gusset plate to form a lattice truss. The vertical and horizontal bars are welded orthogonally, and a channel steel gusset plate is used as a diagonal tie rod at the formed internal corner. Four holes are drilled in the welded steel plate on the crossbeam of the inner formwork lifting frame to serve as jack bases. Wedge jacks are placed on the bases, and the supporting steel pipe 10 is a φ48*3.5 seamless steel pipe.

[0013] The construction method steps for a variable cross-section thin-walled pier lifting frame inverted formwork structure according to this utility model are as follows:

[0014] (1) After the foundation is poured and the main reinforcement of the pier column is pre-embedded, the outer edge line of the pier column is marked out by positioning and measurement, and the stirrups are tied. After the steel formwork is dusted and the release agent is applied, the first layer of outer formwork is assembled and the surrounding truss structure, the closed guardrail, the upper operating platform is assembled, the outer formwork lifting frame and wedge jacks are installed, and the inner formwork slope is adjusted. The hydraulic pipeline is connected and the hydraulic system is adjusted. The supporting steel pipe is inserted above the wedge jack until the steel pipe contacts the foundation. The bolt top support is adjusted so that the top support is tightened against the formwork beam. The formwork is checked.

[0015] (2) After checking that the template is correct, pour the solid section concrete;

[0016] (3) Extend the main reinforcement bars;

[0017] (4) Adjust the bolt top support to detach the crossbeam of the first layer of outer formwork. At this time, the time since the last concrete pour should be more than 12 hours. Lift the outer frame and tie the stirrups at the same time.

[0018] (5) Install the second layer of formwork and adjust the bolt top supports to support the formwork beams;

[0019] (6) Position and install the inner template system and verify its accuracy, and adjust the inner template's slope reduction and lifting hydraulic system;

[0020] (7) Pour the thin-walled section concrete. During the pouring process, the inner formwork system is lifted intermittently with a 2-hour delay. Repeat step (4).

[0021] (8) Remove the lower formwork and use a tower crane to lift and install it piece by piece to the upper part. Adjust the bolt top support to support the formwork beam and check the formwork position;

[0022] (9) Repeat steps (7), (4), and (8) until the pier column diaphragm is reached. Then, lift the inner formwork by 1.2m and set up the bottom formwork of the diaphragm according to the traditional wooden formwork process.

[0023] (10) Repeat steps (8), (7), and (4) to the next diaphragm. Continue this cycle until the solid section at the top of the pier is reached. After lifting, use a tower crane to remove the inner formwork and hoist it to the ground. Install the bottom formwork of the solid section at the top of the pier using traditional formwork techniques.

[0024] (11) Repeat step (8) again and pour the concrete on the top of the pier;

[0025] (12) Use a tower crane to remove the outer formwork in preparation for the construction of the next pier column.

[0026] In step (2), 2m of solid concrete is poured; in step (3), the main reinforcement is extended by 4.5m; in step (4), the stirrups are lifted and tied upwards by a total of 2.25m; in step (7), 2.25m of thin-walled concrete is poured, and 2.1m is lifted in total 2 hours after the pouring is completed; in step (4), the main reinforcement is extended simultaneously if necessary.

[0027] In this invention, the inner formwork is separated from the outer frame. The outer frame integrates a truss structure, an upper and lower operation platform, and a maintenance platform. A lifting system enables the entire outer frame to be lifted, providing an integrated operating platform and working surface, as well as lateral support for the formwork. The inner formwork is formed by circumferentially assembling formwork blocks and reinforced with supports. The inner formwork lifting system directly connects to the formwork, forming the inner formwork system. Together, the inner and outer formwork systems constitute a uniform cross-section thin-walled pier-type inverted formwork structure.

[0028] This utility model's enclosed truss structure serves as the horizontal load-bearing structure for thin-walled pier formwork, and also as the load-bearing carrier for the operating platform, enclosure structure, and hanging frame. The enclosed guardrail provides safety protection for the formwork system. The upper operating platform serves as a platform for rebar installation and tying, and concrete pouring. The lower operating platform serves as the working surface for formwork removal. The maintenance platform serves as a working surface for inspection and maintenance. Supporting rollers enhance the stability of the entire hanging frame and platform. Openings are made on the outer side of the hanging frame, and rebars are inserted into these openings to form the platform's enclosure system.

[0029] This utility model discloses a variable cross-section high pier column lifting-frame inverted formwork structure suitable for rapid construction. It achieves cyclical operation of variable cross-section thin-walled piers through a lifting-frame and inverted formwork cycle, separating the operating platform, lateral supports, and formwork system. The entire operating platform and lateral support structure are detached from the formwork, resulting in reliable connections, a lightweight structure, and high safety. The weight of the formwork is borne by the pier column, and the two-layer cycle is less affected by the age of the concrete, leading to a faster overall construction progress. The lateral supports of the encircling truss eliminate the tie rods used in traditional processes, resulting in better concrete appearance quality. The entire lifting-frame inverted formwork structure functionally disassembles and reassembles traditional formwork, offering reliable structure and simple operation, making it widely applicable in variable cross-section thin-walled piers. Attached Figure Description

[0030] Figure 1 A schematic diagram of the overall model of the variable cross-section high pier column frame-supported inverted formwork structure system;

[0031] Figure 2 Schematic diagram of the external formwork system for the inverted formwork structure of a variable cross-section high pier column;

[0032] Figure 3 A schematic diagram of the internal formwork system for a variable cross-section high pier column formwork structure;

[0033] Figure 4 Plan view of the variable cross-section high pier column frame-supported inverted formwork structure system;

[0034] Figure 5 This is a schematic diagram of a planar steel module;

[0035] Figure 6 Schematic diagram of the lifting system for the inverted formwork structure of a variable cross-section high pier column;

[0036] Figure 7 Schematic diagram of the hydraulic system for the inverted formwork structure of a variable cross-section high pier column;

[0037] Figure 8 A schematic diagram of the construction cross-section of the transition from the solid section to the thin-walled section in the construction of the inverted formwork structure for the variable cross-section high pier column;

[0038] Figure 9 A schematic diagram of the construction cross-section of a standard thin-walled section for the construction of a variable cross-section high pier column formwork structure;

[0039] Figure 10 A schematic diagram of the construction section of the diaphragm for the construction of the inverted formwork structure of the variable cross-section high pier column;

[0040] Figure 11 A schematic diagram of the construction section of the solid section at the top of the pier for the construction of the inverted formwork structure of the variable cross-section high pier column;

[0041] Figure 12 A schematic diagram of the construction process for a variable cross-section high pier column formwork structure;

[0042] In the diagram: 1-Enclosed truss structure, 2-Enclosed guardrail, 3-Upper operating platform, 4-Hanging bracket, 5-Lower operating platform, 6-Maintenance platform, 7-Supporting roller, 8-Bolt support, 9-Outer formwork lifting frame, 10-Supporting steel pipe, 11-Wedge jack, 12-Outer formwork lifting system, 13-Outer formwork, 14-Inner formwork, 15-Inner formwork lifting frame, 16-Inner formwork lifting system, 17-Short side truss, 18-Long side truss, 19-Hydraulic system, 20-High-strength bolt, 21-End plate bolt hole, 22-Back rib, 23-Oil cylinder, 24-Adjusting formwork segment. Detailed Implementation

[0043] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Example 1

[0044] like Figure 1 — Figure 7 In this embodiment, the variable cross-section high pier column lifting frame inverted formwork structure consists of an upper operating platform 3, a lower operating platform 5, a surrounding truss structure 1, a closed guardrail 2, a hanging frame 4, a maintenance platform 6, an inner formwork 14, an outer formwork 13, an outer formwork lifting system 12, and an inner formwork lifting system 16, as detailed below:

[0045] The enclosing truss structure 1 consists of 100*10 equilateral angle steel as chords and 63*63*6 angle steel as web members, forming a truss cross-section with an outer contour of 1.2m*1.3m. The enclosing truss structure 1 is formed by connecting four truss sections sequentially with high-strength bolts, creating a rectangular truss enclosure around the pier column. This enclosure serves as the horizontal load-bearing structure for the thin-walled pier formwork and also as the load-bearing carrier for the operating platform, enclosure structure, and hanging frame. The enclosed guardrail 2 is made of 50*50*5 steel pipes to form a safety barrier for the formwork system and is directly connected to the enclosing truss structure 1 with high-strength bolts. The upper operating platform 3 consists of a 2.5mm checkered steel plate laid on the enclosing truss structure 1, serving as a platform for rebar installation and tying, and concrete pouring. The hanging frame 4 is made of 80*6 equilateral angle steel with a length of 4.8m. It is bolted to the welded crossbeams under the enclosing truss structure 1. 2.8m below the hanging frame 4, a 50*5 double-braced angle steel crossbeam is installed and covered with 2.5mm checkered plates to form a lower operating platform 5 as the working surface for formwork removal. At the bottom of the hanging frame 4, a 50*5 double-braced angle steel crossbeam is also laid with 2.5mm checkered plates to form a maintenance platform 6, serving as a platform for inspection and maintenance. Support rollers 7 are installed at the bottom of the hanging frame 4, allowing it to roll upwards along the pier, enhancing the stability of the entire hanging frame 4 and platform. Holes are drilled every 60cm above the two platforms on the outer side of the hanging frame 4, with reinforcing bars inserted into the holes to form the platform's enclosure system. Bolted top supports 8 are made of φ28 precision-rolled threaded steel with welded channel-shaped top supports at the ends. Their tail ends are supported by special nuts on the perforated steel sections of the enclosing truss. During use, the top supports are tightened to press against the formwork beams by tightening the special bolts.

[0046] The external formwork lifting frame 9 consists of two I18 channel steel supports welded together to form a rectangular vertical bar. The horizontal bar is formed by two I18 channel steel bars back-to-back, spaced 50mm-60mm apart, connected by a gusset plate to form a lattice truss. I100 channel steel is used as a diagonal brace above it, connecting to the vertical bar. After installation, the external formwork lifting frame 9 is integrated into a single unit via the truss formed by the welded channel steel gusset plates. The external formwork lifting frame 9 is connected to the supporting steel pipe 10 inserted into the concrete via wedge jacks 11. Four holes are drilled in the welded steel plate on the horizontal beam of the external formwork lifting frame 9 to serve as jack bases. The wedge jacks 11 are placed on the bases. The supporting steel pipe 10 is a φ48*3.5 seamless steel pipe. The aforementioned external formwork lifting frame 9, supporting steel pipe 10, and wedge jacks 11 together constitute the external formwork lifting system 12, which is connected to the surrounding truss structure 1 via high-strength bolts. During lifting, the wedge jack 11 climbs on the supporting steel pipe 10 and drives the entire outer formwork lifting system 12 and the outer frame to rise.

[0047] The outer formwork 13 is 2.25m high and is a 5mm thick monolithic steel formwork. The four corners are rounded. The large surface consists of two 2.95m wide steel formworks, and the small surface consists of a 2.9m wide steel formwork, assembled with the rounded formworks. There are a total of two sets of outer formwork, comprising 20 pieces. Each piece has a smooth, flat vertical surface. The vertical back ribs are made of No. 5 channel steel spaced 30cm apart. Angle steel is welded around the perimeter of the formwork, and holes are drilled for bolt connections between the formwork sections. The two ends of the back ribs are firmly welded to the angle steel. A formwork beam formed by two No. 14 channel steels is installed 1 / 5 of the way in from both ends of the back ribs. After this beam is installed, it is secured by bolt supports 8. There are two sets of outer formwork 13. One set is installed first, and after concrete pouring, the next set is installed and concrete is poured. The lower set of outer formwork is then disassembled piece by piece and lifted to the top by a tower crane for reinstallation. Throughout the construction process, the two sets of outer formwork are continuously cyclically disassembled and reassembled from bottom to top. The outer formwork 13 is sloped by using a small formwork panel to "clamp" the large formwork panel. A flange and oblong holes are installed at the end of the large formwork panel. The corresponding small formwork panel is perpendicular to the large formwork panel and has bolt holes spaced 120-140mm apart. High-strength bolts are used to connect it to the oblong holes of the outer formwork panel. In the first cycle of outer formwork 13, the operating platform is raised to a cumulative height of 4.8m, and the remaining rebar is tied. Simultaneously, the internal formwork system is installed, and the slope of the inner formwork is adjusted. After verifying the formwork, concrete can be poured. Once the concrete has initially set, the bolt supports 8 can be removed, creating space for formwork relocation between the truss and the formwork. At this point, the lower formwork is removed for the first time, and the upper formwork is fixed with bolt supports 8. As the inner formwork is raised with the pouring, a new thin-walled pouring space is formed. Subsequently, once the lower space reaches the installation height, the suspended platform can be installed. At this point, the installation of all platforms for the lifting frame formwork is complete, and subsequent construction can proceed according to standard procedures.

[0048] The inner formwork 14 is similar in structure to the outer formwork 13. The overall size of the formwork is determined according to the cross-sectional outline of the thin-walled pier cavity. A 5mm steel plate is used as the panel, with a height of 2.25m. The vertical back ribs are made of No. 5 channel steel arranged at 30cm intervals, and angle steel is welded to the top and bottom edges for locking. The division and connection of the formwork blocks are all in the plane position. Double No. 14 channel steel is set at the 1 / 5 position inward from both ends of the vertical back ribs of the inner formwork 14 as the formwork beam. The large-area formwork is set into 2 modules, with 4 supports facing each other. The end corner formwork is divided into 3 modules, and the formwork can only be connected to the formwork outside the corner. Lateral supports are set on the formwork beams and connected to the nearest support to form a skeleton. When in use, after all the supports are connected, bamboo plywood can be laid on it to form the operating platform of the inner formwork.

[0049] The inner formwork lifting frame 15 consists of two I18 channel steel supports welded together to form a rectangular cross-section vertical bar. The horizontal bar is formed by two I18 channel steel bars back-to-back, spaced 50mm-60mm apart, connected by a gusset plate to form a lattice truss. The vertical and horizontal bars are orthogonally welded, and channel steel gusset plates are used as diagonal braces at the resulting internal corners. The inner formwork lifting frame 15 is connected to the supporting steel pipe 10 inserted into the concrete via wedge jacks. Four holes are drilled in the welded steel plate on the horizontal beam of the inner formwork lifting frame 15 to serve as jack bases, on which wedge jacks 11 are placed. The supporting steel pipe 10 is a φ48*3.5 seamless steel pipe. The aforementioned inner formwork lifting frame 9, supporting steel pipe 10, and wedge jacks 11 together constitute the inner formwork lifting system 16, which is connected to the inner formwork horizontal beam via high-strength bolts. During lifting, wedge jacks 11 climb on the supporting steel pipe 10, driving the entire inner formwork lifting system 16 and the inner formwork 14 to rise. The inner formwork 14 is lifted intermittently into position using a slipform process during and after pouring, depending on the concrete's setting state. Alternatively, after the concrete has fully solidified, a hydraulic system 19 is used to retrieve and demold it, followed by lifting, jacking, and verification. Figure 7 The hydraulic system 19 shown consists of a cylinder 23 and a formwork adjustment section 24. The inner formwork is positioned first, with an overlap of at least 15cm with the poured concrete. The outer formwork 13 is then tilted and positioned, supported by bolts (threaded rods). After verification, the pouring of the 2.4m section of concrete can begin. During and after the pouring process, the inner formwork 14 is lifted using a sliding formwork technique. 4-6 hours after pouring, once the concrete has fully set, the bolt supports can be removed, and the surrounding truss structure 1 is lifted, with reinforcing steel tied simultaneously. This completes one standard thin-walled section construction cycle. During the process, the distance between each formwork and the centerline plumb line is checked using two 15kg plumb bobs to ensure the accuracy of formwork installation and slope finishing. Simultaneously, a level is marked on the supporting steel pipe 10 to control the overall horizontal height of the formwork installation. Example 2

[0050] like Figure 1 — Figure 12 In this embodiment, the variable cross-section high pier column lifting frame inverted formwork structure and its construction process include the construction of the solid section at the bottom of the pier, the standard thin-walled section in the middle, the solid section at the top of the pier, and the transverse diaphragm. Each pier column only requires the installation and dismantling of the working platform once.

[0051] Specifically as follows:

[0052] The system includes a surrounding truss structure 1, a closed guardrail 2, an upper operating platform 3, a hanging frame 4, a lower operating platform 5, a maintenance platform 6, supporting rollers 7, bolt supports 8, an inner formwork 14, an outer formwork 13, an outer formwork lifting system 12, and an inner formwork lifting system 16. The surrounding truss structure 1 consists of 100*10 equilateral angle steel as chords and 63*63*6 angle steel as web members, forming a truss cross-section with an outer contour of 1.2m*1.3m. The surrounding truss structure 1 connects four truss sections sequentially with high-strength bolts to form a rectangular truss enclosure around the pier column, serving as the horizontal load-bearing structure of the thin-walled pier formwork and as the load-bearing carrier for the operating platform, enclosure structure, and hanging frame. The closed guardrail 2 is made of 50*50*5 steel pipes to form a safety barrier for the formwork system and is directly connected to the surrounding truss structure 1 with high-strength bolts. The upper operating platform 3 is constructed by laying 2.5mm checkered steel plates on the surrounding truss structure 1, serving as a platform for rebar installation and concrete pouring. The hanging frame 4 is made of 80*6 equilateral angle steel with a length of 4.8m. It is bolted to the welded crossbeams under the enclosing truss. 2.8m below the hanging frame 4, a 50*5 double-braced angle steel crossbeam is installed and covered with 2.5mm checkered plates to form a lower operating platform for formwork removal. At the bottom of the hanging frame 4, a maintenance platform 6 is formed using 50*5 double-braced angle steel crossbeams and covered with 2.5mm checkered plates, serving as a platform for inspection and maintenance. Support rollers 7 are installed at the bottom of the hanging frame 4, allowing it to roll upwards along the pier, enhancing the stability of the entire hanging frame 4 and platform. Holes are drilled every 60cm above the two platforms on the outer side of the hanging frame 4, with reinforcing bars inserted into the holes to form the platform's enclosure system. The bolted top supports 8 are made of φ28 precision-rolled threaded steel with welded channel-shaped top supports at the ends. Their tail ends are supported by special nuts on the perforated steel sections of the enclosing truss. During use, the top supports are tightened to press against the formwork beams by tightening the special bolts.

[0053] The external formwork lifting frame 9 consists of two I18 channel steel supports welded together to form a rectangular vertical bar. The horizontal bar is formed by two I18 channel steel bars back-to-back, spaced 50mm-60mm apart, connected by a gusset plate to form a lattice truss. I100 channel steel is used as a diagonal brace above it, connecting to the vertical bar. After installation, the external formwork lifting frame 9 is integrated into a single unit via the truss formed by the welded channel steel gusset plates. The external formwork lifting frame 9 is connected to the supporting steel pipe 10 inserted into the concrete via wedge jacks 11. Four holes are drilled in the welded steel plate on the horizontal beam of the external formwork lifting frame 9 to serve as jack bases. The wedge jacks 11 are placed on the bases. The supporting steel pipe 10 is a φ48*3.5 seamless steel pipe. The aforementioned external formwork lifting frame 9, supporting steel pipe 10, and wedge jacks 11 together constitute the external formwork lifting system 12, which is connected to the surrounding truss structure 1 via high-strength bolts. During lifting, the wedge jack 11 climbs on the supporting steel pipe 10 and drives the entire outer formwork lifting system 12 and the outer frame to rise.

[0054] The outer formwork 13 is 2.25m high and is a 5mm thick monolithic steel formwork. The four corners are rounded. The large surface consists of two 2.95m wide steel formworks, and the small surface consists of a 2.9m wide steel formwork, which is assembled with the rounded formworks to form the outer formwork 13. There are a total of two sets of 20 outer formwork pieces. Each piece has a smooth, flat vertical surface. The vertical back ribs 22 are made of No. 5 channel steel spaced 30cm apart. Angle steel is welded around the perimeter of the formwork, and holes are drilled for bolt holes 21 for connecting the formwork pieces. The two ends of the back ribs 22 are firmly welded to the angle steel. A template beam formed by double-supported No. 14 channel steel is installed at 1 / 5 of the distance inward from both ends of the back rib 22. After the template is installed in place, it is tightened by the top support of bolt top bracing 8. There are two sets of outer templates 13. One set is installed first, and after the concrete is poured, the other set is installed and concrete is poured. Subsequently, the lower set of outer templates is disassembled piece by piece and lifted to the top by a tower crane for reinstallation. Throughout the construction process, the two sets of outer templates 13 are continuously cyclically disassembled and assembled from bottom to top. The slope of the outer template 13 is achieved by the smaller template "clamping" the larger template. Flanges and oblong holes are set at the ends of the larger template. The corresponding smaller template plane is perpendicular to the larger template and has bolt holes with a spacing of 120-140mm. High-strength bolts 20 are used to bolt to the oblong holes of the outer template 13. The first cycle of the outer template 13 involves the operating platform being lifted to a cumulative height of 4.8m and the remaining steel reinforcement binding being completed. At the same time, the inner template system is installed and the slope of the inner template 14 is adjusted. After the template is checked, concrete can be poured. Once the concrete has initially set, the bolt supports 8 can be removed, creating space for formwork relocation between the truss and the formwork. At this point, the lower formwork is removed for the first time and installed on top, secured with bolt supports 8. As the inner formwork 14 is lifted during pouring, a new thin-walled pouring space is formed. Once the lower space reaches the installation height, the suspended platform can be installed. At this point, the installation of all platforms for the formwork is complete, and subsequent construction can proceed according to standard procedures.

[0055] The inner formwork 14 is similar in structure to the outer formwork 13. The overall size of the formwork is determined according to the cross-sectional outline of the thin-walled pier cavity. A 5mm steel plate is used as the panel, with a height of 2.25m. The vertical back ribs 22 are made of No. 5 channel steel arranged at 30cm intervals, with angle steel welded to the top and bottom edges. The division and connection of the formwork blocks are all in the plane position. Double No. 14 channel steel is set at the two ends of the vertical back ribs 22 of the inner formwork 14 at the 1 / 5 position inward as the formwork beam. The large formwork is set into 2 modules, with 4 supports facing each other. The end corner formwork is divided into 3 modules, and the formwork can only be connected to the formwork outside the corner. Lateral supports are set on the formwork beams and connected to the nearest support to form a skeleton. When in use, after all the supports are connected, bamboo plywood can be laid on it to form the operating platform of the inner formwork.

[0056] The inner formwork lifting frame 15 consists of two I18 channel steel supports welded together to form a rectangular vertical bar. The horizontal bar is formed by two I18 channel steel bars back-to-back, spaced 50mm-60mm apart, connected by a gusset plate to form a lattice truss. The vertical and horizontal bars are welded orthogonally, and channel steel gusset plates are used as diagonal braces at the resulting internal corners. The inner formwork lifting frame 15 is connected to the supporting steel pipe 10 inserted into the concrete via wedge jacks 11. Four holes are drilled in the welded steel plate on the horizontal beam of the inner formwork lifting frame 15 to serve as jack bases, on which the wedge jacks 11 are placed. The supporting steel pipe 10 is a φ48*3.5 seamless steel pipe. The aforementioned inner formwork lifting frame 9, supporting steel pipe 10, and wedge jacks 11 together constitute the inner formwork lifting system 16, which is connected to the inner formwork horizontal beam via high-strength bolts. During lifting, the wedge jack 11 climbs on the supporting steel pipe 10 and drives the entire inner formwork lifting system 16 and the inner formwork 14 to rise.

[0057] When constructing the standard section to the position of the diaphragm, the inner formwork is lifted 1.2m directly (for a diaphragm thickness of 40cm and 40cm chamfers at the top and bottom). This is achieved by pre-embedding bolts in the thin-walled section, setting up distribution beams, erecting 10cm square timber, and laying bamboo plywood. A chamfered suspended formwork is then installed above. The manhole location uses bamboo plywood and square timber to create the diaphragm formwork section (see [section description missing]). Figure 10 Fixing bolts are inserted into the bolt sleeves pre-embedded in the thin-walled concrete. Load-bearing beams are erected, wooden joists are distributed, and permanent bottom formwork for the diaphragms is constructed using wooden templates. The diaphragm reinforcement is tied, and after inspection and approval, the chamfered side formwork is installed. After verification, the diaphragms and thin-walled concrete are poured simultaneously, extending approximately 20cm beyond the chamfer. Once the concrete has initially set, construction can proceed in a cyclical manner to the next diaphragm, following the standard thin-walled section construction method. Key points for diaphragm construction include ensuring the lower pre-embedded sleeves are connected with pre-embedded reinforcement to guarantee load-bearing capacity; using 18-inch I-beams as beams for the bottom formwork to ensure load-bearing capacity; and constructing the bottom formwork using square timber and bamboo plywood. To ensure construction safety, the bottom formwork is not removed but serves as permanent formwork.

[0058] The installation of the bottom formwork for the solid section at the pier top is consistent with that of the bottom formwork for the transverse diaphragm. It is connected to the transverse beam via embedded parts, and square timber and bamboo plywood are erected. The first pour of concrete should extend beyond the chamfer and cover at least 40-50cm of the top surface of the permanent formwork. After the concrete has solidified, the working platform can be raised and the outer formwork overturned to complete the pouring of the solid pier top. Figure 11 .

[0059] In summary, the outer frame of the outer formwork integrates a truss structure, an upper and lower operation platform, and a maintenance platform. The entire outer frame is lifted via a lifting system, providing an integrated operating platform and working surface, as well as lateral support for the formwork. The inner formwork is formed by circumferentially assembling formwork blocks and reinforced with supports. The inner formwork lifting system directly connects to the formwork, forming the inner formwork system. Together, the inner formwork and templates constitute a uniform cross-section thin-walled pier-type inverted formwork structure.

[0060] The construction method of this utility model for a rapid construction method of a variable cross-section bridge high pier column lifting frame inverted formwork structure is as follows: After the pier cap is poured and the main reinforcement of the pier column is pre-embedded, the outer edge line of the pier column is marked out by positioning and measurement, and the stirrups are tied. The first step is to remove dust from the steel formwork, apply release agent, assemble the first layer of outer formwork and assemble the surrounding truss structure 1 and the enclosed guardrail 2, install the operating platform 3, install the outer formwork lifting frame 9 and wedge jacks 11, and adjust the slope of the inner formwork. Connect the hydraulic pipeline and adjust the hydraulic system 19, which consists of oil cylinders 23 and formwork adjustment sections 24. Insert the support steel pipe 10 above the wedge jacks 11 until the steel pipe contacts the pier cap, adjust the bolt top support 8 to make the top support tighten the formwork crossbeam, and after checking that the formwork is correct, proceed to the second step of pouring solid concrete. Step 1: Concrete 2m; Step 2: Extend the main reinforcement by 4.5m; Step 3: Adjust the bolt top support 8 to detach the crossbeam of the first layer (also called the lower layer) of outer formwork. At this time, the time since the last concrete pour should be more than 12 hours. Lift the outer frame and tie the stirrups simultaneously. If necessary, extend the main reinforcement simultaneously. Lift and tie the stirrups upwards by a total of 2.25m; Step 4: Install the second layer (also called the lower layer) of formwork and adjust the bolt top support 8 to support the formwork crossbeam; Step 5: Position and install the inner formwork system and verify its accuracy. Adjust the slope of the inner formwork and the lifting hydraulic system 19; Step 6: Pour 2.25m of thin-walled concrete. During the pouring process, the inner formwork system is lifted intermittently with a 2-hour delay. After the pouring is completed, lift a total of 2.1m. Repeat Step 4. Step 7: Remove the lower layer of formwork and use a tower crane to lift and install it piece by piece to the top. Adjust the bolt top support 8 to support the formwork crossbeam and verify the formwork position. Repeat steps 7, 4, and 8 until the diaphragm position is reached. Then, in step 9, lift the inner formwork 1.2m and erect the bottom formwork for the diaphragm using traditional wooden formwork techniques. Repeat steps 8, 7, and 4 until the next diaphragm. Continue this cycle until the solid section at the top of the pier. In step 10, after lifting, use a tower crane to remove the inner formwork and hoist it to the ground. Install the bottom formwork for the solid section at the top of the pier using traditional formwork techniques. Repeat step 8 again. In step 11, pour the concrete at the top of the pier. In step 12, use a tower crane to remove the outer formwork in preparation for the construction of the next pier.

[0061] This utility model discloses a variable cross-section high pier column lifting-frame inverted formwork structure suitable for rapid construction. It achieves cyclical operation of the variable cross-section thin-walled pier through a lifting-frame and inverted formwork cycle, allowing the operating platform, lateral supports, and formwork system to be separated. The entire operating platform and lateral support structure are detached from the formwork, resulting in reliable connections, a lightweight structure, and high safety. The construction process, divided from the pier column location, mainly includes the construction of the solid section at the pier bottom, the standard thin-walled section, the diaphragm, and the solid section at the pier top. Correspondingly, the formwork system at the pier bottom section completes the installation of the first layer of formwork, the surrounding truss, the second layer of formwork, the operating platform, and the inner formwork. At the pier top, the inner formwork is gradually removed, the two layers of formwork are removed, and the surrounding truss and platform are dismantled. The construction flow chart of the variable cross-section high pier column lifting-frame inverted formwork structure is shown below. Figure 12 This utility model discloses a variable cross-section high pier column lifting frame inverted formwork structure suitable for rapid construction. The overall construction progress is fast, and the lateral support of the ring truss eliminates the tie rods in the traditional process, resulting in good concrete appearance quality. The entire lifting frame inverted formwork structure is a functional decomposition and recombination of traditional formwork. Its structure is reliable and easy to operate, and it can be widely used in variable cross-section thin-walled piers.

[0062] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A variable cross-section high pier column formwork structure suitable for rapid construction, characterized in that, The system includes an upper operating platform (3), a lower operating platform (5), a surrounding truss structure (1), a closed guardrail (2), a hanging frame (4), an outer formwork (13), an inner formwork (14), an outer formwork lifting system (12), an inner formwork lifting system (16), and a maintenance platform (6). The surrounding truss structure (1) is formed by connecting four trusses in sequence with high-strength bolts to form a rectangular truss enclosure around the pier. The closed guardrail (2) is directly connected to the surrounding truss structure (1) with high-strength bolts. The upper operating platform (3) is set in the enclosure. The ring truss structure (1) is connected to the lower part of the ring truss structure (1) by bolts. The lower part of the hanging frame (4) is provided with a lower operating platform (5). The bottom of the hanging frame (4) is provided with a maintenance platform (6). The bottom of the hanging frame (4) is provided with a support roller (7) that can roll upward along the pier. Several holes are opened on the lower operating platform (5) and maintenance platform (6) on the outside of the hanging frame (4). Reinforcing bars are inserted into the holes. The ring truss structure (1) is connected to the outer formwork (13) by bolt top support (8). The external formwork lifting system (12) includes an external formwork lifting frame (9), a supporting steel pipe (10), and a wedge jack (11). The external formwork lifting frame (9) is connected to the ring truss structure (1) by bolts, and the external formwork lifting frame (9) is connected to the supporting steel pipe (10) inserted into the concrete by the wedge jack (11). The inner formwork lifting system (16) includes an inner formwork lifting frame (15), a supporting steel pipe (10), and a wedge jack (11). The inner formwork lifting frame (15) is connected to the supporting steel pipe (10) inserted into the concrete through the wedge jack (11). The inner formwork lifting frame (15) is connected to the crossbeam of the inner formwork (14) through high-strength bolts.

2. The variable cross-section high pier column formwork structure suitable for rapid construction according to claim 1, characterized in that, The encircling truss structure (1) is composed of 100*10 equilateral angle steel as chords and 63*63*6 angle steel as web members, forming a cross-sectional outer contour of 1.2m*1.3m. The enclosed guardrail (2) is made of 50*50*5 steel pipe. The upper operating platform (3) is a 2.5mm patterned steel plate laid on the encircling truss structure (1). The bolt top support (8) is made of φ28 precision rolled threaded steel. The end is welded with a channel-shaped top support to tighten the outer template (13) crossbeam. The tail end is supported by a nut on the perforated steel of the encircling truss structure (1).

3. A variable cross-section high pier column formwork structure suitable for rapid construction, as described in claim 1, is characterized in that... The bracket (4) is made of 80*6 equilateral angle steel and has a length of 4.8m. A 50*5 double angle steel crossbeam is set at the bottom 2.8m of the bracket (4) and a 2.5mm patterned plate is laid to form a lower operating platform (5). A 50*5 double angle steel crossbeam is set at the bottom of the bracket (4) and a 2.5mm patterned plate is laid to form a maintenance platform (6). Holes are opened every 60cm on the outer side of the bracket (4) on the two platforms.

4. A variable cross-section high pier column formwork structure suitable for rapid construction, as described in claim 1, is characterized in that... The outer template (13) is an integral large steel template with a height of 2.25m and a thickness of 5mm. The four corners are arc-shaped templates. The large surface is composed of two 2.95m wide steel templates and the small surface is composed of a 2.9m wide steel template assembled with the arc templates. The vertical back ribs are arranged with No. 5 channel steel at 30cm intervals. Angle steel is welded around the template and holes are drilled as bolt holes for connecting the templates. The two ends of the back ribs are firmly welded to the angle steel. The template crossbeams formed by double No. 14 channel steel are set at 1 / 5 of the distance from the two ends of the back ribs. After the template is installed in place, it is supported by the top support of the bolt top support (8). The inner template (14) is determined according to the cross-sectional outline of the thin-walled pier. A 5mm steel plate is used as the panel, with a height of 2.25m. The vertical back ribs are arranged with No. 5 channel steel at 30cm intervals. Angle steel is welded to the upper and lower ends for locking. The division and connection of the template blocks are all in the plane position. Double No. 14 channel steel is set at 1 / 5 position inward at both ends of the vertical back ribs of the inner template as template beams. The large template is set as 2 modules, with 4 supports in opposite directions. The end corner template is divided into 3 modules, and the template can only be connected to the template outside the corner. Lateral supports are set on the template beams and connected to the nearest support to form a skeleton. When in use, bamboo plywood can be laid on it after all supports are connected to form the operating platform of the inner template.

5. A variable cross-section high pier column formwork structure suitable for rapid construction according to claim 1, characterized in that, The outer formwork lifting frame (9) is composed of two I18 channel steels welded together to form a rectangular cross-section vertical bar. The horizontal bar is composed of two I18 channel steels back to back and 50mm-60mm apart, connected by a lacing plate to form a lattice truss. I100 channel steel is used as a diagonal brace to connect with the vertical bar above. The installed outer formwork lifting frame (9) is connected as a whole by the truss welded by the channel steel lacing plate. Four holes are drilled on the horizontal bar of the outer formwork lifting frame (9) to serve as a base. A wedge jack (11) is placed on the base. The supporting steel pipe (10) is a φ48*3.5 seamless steel pipe.

6. A variable cross-section high pier column formwork structure suitable for rapid construction, as described in claim 1, is characterized in that... The inner formwork lifting frame (15) consists of two I18 channel steels welded together to form a rectangular cross-section vertical bar. The horizontal bar consists of two I18 channel steels back to back and 50mm-60mm apart, connected by a gusset plate to form a lattice truss. The vertical bar and the horizontal bar are welded orthogonally, and a channel steel gusset plate is used as a diagonal tie rod at the formed inside corner. Four holes are drilled on the horizontal beam of the inner formwork lifting frame (15) to serve as the jack base. A wedge jack (11) is placed on the base. The supporting steel pipe (10) is a φ48*3.5 seamless steel pipe.

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