A slip form construction method for a prestressed concrete storage tank wall

Abstract

This invention provides a slipform construction method for prestressed concrete storage tank walls. By refining construction steps, establishing avoidance rules, and adopting precision control measures, it solves the technical problems of difficulty in controlling the location of concealed works and avoiding collisions within a limited pouring space. The steps of this invention are as follows: S1. After the concealed works of the first formwork wall at the bottom of the storage tank are inspected and accepted, the slipform system is assembled; S2. After the concrete of the first formwork wall at the bottom of the storage tank is poured and reaches the demolding strength, a trial lift is performed and the slipform system is thoroughly inspected; S3. Concealed works are installed sequentially according to a preset order, coordinating the synchronous progress of various construction procedures; S4. When the steel formwork is raised to the preset elevation of the tank wall, it is slowly lifted for air sliding until the lower edge of the steel formwork reaches the top surface of the tank wall concrete; S5. After the concrete of the last section of the wall reaches the preset strength, the slipform system is dismantled using a tower crane.

Description

Technical Field

[0001] This invention relates to the field of prestressed concrete storage tank construction technology, specifically to a slipform construction method for the tank wall of a prestressed concrete storage tank. Background Technology

[0002] Prestressed concrete storage tanks are widely used for storing cryogenic media such as liquefied natural gas (LNG), liquid ammonia, and ethylene due to their excellent sealing performance, structural safety, and durability. These tanks typically have large three-dimensional dimensions and complex concealed engineering systems within the tank walls, requiring high precision and quality in construction.

[0003] Prestressed concrete tank wall construction typically employs the formwork method, but this method suffers from drawbacks such as numerous horizontal construction joints, long construction periods, and high safety risks. Slipform construction, as a continuous concrete pouring method, offers advantages such as fast construction speed, good integrity, and precise structural dimensions, and has been successfully applied in the construction of silos, chimneys, bridge piers, and other structures.

[0004] However, applying the continuous slipform construction technique to the tank wall construction of prestressed concrete storage tanks presents several technical challenges, including controlling the curvature and verticality of the embedded steel plates, potential collisions between the studs of the embedded steel plates and the embedded corrugated pipes of the prestressing system and the reinforcing steel bars in the tank wall, and the coordination of the spatial arrangement of concealed works that can hinder construction progress. Therefore, a slipform construction method suitable for prestressed concrete storage tank walls is urgently needed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a slipform construction method for prestressed concrete storage tank walls. By refining construction steps, establishing avoidance rules, and adopting precision control measures, it solves technical problems such as difficulty in controlling the location of concealed works installation and difficulty in avoiding collisions within a limited pouring space.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A slipform construction method for the wall of a prestressed concrete storage tank includes the following steps: S1. Template Assembly: After the concealed works of the first formwork wall at the bottom of the storage tank are inspected and accepted, the slipform system will be assembled. S2, Initial slipforming: After the concrete of the first formwork wall at the bottom of the storage tank is poured and reaches the demolding strength, a trial lift is carried out and the slipforming system is fully inspected. S3. Continuous slipforming: The concealed works are installed in sequence according to the preset order, and the various construction procedures are coordinated to proceed simultaneously. Among them, when various wall steel bars, prestressed corrugated pipes and embedded steel plate studs collide, the avoidance rules are followed, and precision control measures are implemented during construction and installation. S4. Final slide: After the steel formwork is slided to the preset elevation of the tank wall, the steel formwork is slowly raised to slide without load until the lower part of the steel formwork is raised to the top surface of the concrete of the tank wall. S5. System Dismantling: After the final section of the wall concrete reaches the preset strength, the slipform system is dismantled using a tower crane.

[0007] The slipform system of this invention includes a template system, a lifting system, and a platform system; (1) The formwork system includes steel formwork, a surrounding ring, and a support frame; the surrounding ring is fixedly installed on the outer side of the steel formwork along the circumference; the support frame 3 is fixed on the outer side of the steel formwork; (2) The lifting system includes jacks, lifting frames and support rods; the lifting frames are arranged at equal intervals along the circumference of the center of the tank wall, and the lifting frames and support frames are fixed together; the jacks are installed on the lifting frames and are evenly distributed along the circumference; the support rods are set in the middle of the steel template and are connected to the jacks. (3) The platform system is arranged circumferentially along the tank wall and fixed on the lifting frame.

[0008] Step S2 of the present invention includes the following steps: initial slipforming is a trial slipforming process before continuous construction; after pouring concrete for the first formwork wall at the bottom of the storage tank, all jacks are raised simultaneously to test the concrete strength; if the concrete reaches the demolding strength, the steel formwork is gradually slip-raised, and the lifting system and formwork system are comprehensively inspected at the same time.

[0009] Step S3 of the present invention includes the following steps: (1) Normal slipforming: The time interval between each slipforming is determined according to the concrete setting time, and it is necessary to ensure that the concrete reaches the demolding strength. In order to ensure the synchronization of slipforming, the position of the limit buckle on the support rod is adjusted before each slipforming so that each jack stops synchronously when it is raised to the position. When the support rod is extended, adjacent joints are staggered and the number of joints at the same horizontal section does not exceed 25% of the total number of joints. The joints adopt the socket connection, and the joint is ground smooth to ensure that the jacks can pass smoothly.

[0010] (2) Reinforcing steel reinforcement binding in the wall; (3) Corrugated pipe installation: Prestressed corrugated pipes should be installed at the same time as the steel bars are tied. After the prestressed corrugated pipes are installed in the predetermined position, both the horizontal and vertical prestressed corrugated pipes are fixed by lapping the fixing bars on the horizontal steel bars of the wall. The corrugated pipes and the fixing bars are tied together. (4) Processing and installation of embedded steel plates; (5) Concrete construction; (6) Concrete surface treatment and curing; (7) Verticality measurement: Several measurement points are evenly distributed on the tank wall. A plumb line is suspended from the bottom of the platform system and a cross line is drawn on the ground as the measurement reference point. The verticality deviation of the tank wall is judged by measuring the offset between the tip of the plumb line and the reference point, combined with the distance between the plumb line and the tank wall.

[0011] In step S3 of this invention, the avoidance rules include: the positions of the tank wall reinforcement and prestressed corrugated pipe cannot be adjusted; when the prestressed corrugated pipe collides with the wall tie bar, the position of the tie bar is slightly adjusted; when the embedded steel plate studs, stiffening ribs collide with other concealed works, the positions of individual studs and stiffening ribs are adjusted.

[0012] In step S3 of the present invention, the precision control measures include: welding stiffening ribs on both sides of the vertical pre-embedded steel plate in the width direction to enhance its lateral stiffness and ensure verticality; welding stiffening ribs with the same curvature on both sides of the circumferential pre-embedded steel plate in the width direction to enhance its lateral stiffness and ensure curvature; and fixing the prestressed corrugated pipe with fixing ribs, which are arranged at intervals along the length of the corrugated pipe.

[0013] In step S3 of this invention, before installing the embedded steel plate, check its position, elevation, and specifications, and mark it on the slipform platform. It must not be welded to the reinforcing bars. The studs and stiffening ribs of the embedded steel plate are inserted into the grid formed by the wall reinforcing bars. When collision occurs, the studs and stiffening ribs are adjusted with the principle of not moving the wall reinforcing bars. The weld seams of the vertical embedded steel plates are staggered from the butt joints of the circumferential embedded steel plates. During the slipforming process, the embedded parts and reserved holes that need to be chiseled out should be chiseled out in time after demolding to avoid damaging the surface of the tank wall. Since the vertical embedded steel plates are greatly disturbed by multiple processes, they should be checked multiple times after installation and positioning. After the steel formwork is reinforced, they should be checked one by one. If excessive deformation is found, it should be adjusted and dealt with in time.

[0014] In the wall reinforcement binding step S3 of the present invention, To ensure the accurate positioning of the vertical reinforcement bars in the wall, circumferential positioning reinforcement bars are welded to the horizontal beam of the lifting frame, and positioning rings are then welded onto the positioning reinforcement bars. The vertical reinforcement bars are then fitted into the positioning rings, which controls the reinforcement bar spacing and the thickness of the protective layer. The positioning control of the horizontal reinforcement bars in the wall can be achieved by marking the spacing lines on the vertical reinforcement bars in advance to control the binding spacing. The net distance between the top of the steel formwork and the horizontal beam of the lifting frame is controlled to facilitate the insertion of the horizontal reinforcement bars in the wall and to ensure that at least two binding horizontal reinforcement bars are visible on the concrete surface.

[0015] Step S4 of this invention specifically includes the following steps: slowing down the slipforming speed while simultaneously performing a comprehensive leveling and alignment of the formwork system; the elevation adjustment and center correction of the entire steel formwork should be completed before slipforming to the last formwork to ensure uniform alignment of the top structure and guarantee the accuracy and correct position of the tank wall top elevation; after all concrete is poured, the load that can be removed from the platform system should be promptly unloaded, and the steel formwork should continue to be raised according to the procedure of the continuous slipforming stage until the lower end of the steel formwork is raised to the top of the tank wall concrete, entering the empty slipforming state; during the empty slipforming process, transverse steel bars are used to connect each support rod by spot welding for transverse horizontal reinforcement.

[0016] Step S5 of the present invention specifically includes the following steps: after the wall concrete reaches the preset strength, the slipform system is dismantled; before dismantling, all tools and materials on the platform are cleaned up and all construction loads are removed; during dismantling, the lifting system is dismantled first, then the formwork system is dismantled, and finally the platform system is dismantled; wherein, the platform system is cut and separated into sections, and the sections are lifted to the ground by a tower crane to complete the dismantling.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention systematically applies the slipform construction process to the construction of prestressed concrete tank walls, giving full play to the continuous forming advantages of slipform construction, reducing the number of horizontal construction joints and improving the overall integrity of the concrete tank. In traditional formwork construction, the construction of the outer concrete tank is on the critical path, with little room for adjustment of the schedule; after adopting slipform construction in this invention, the construction of the outer concrete tank is transformed into a non-critical path, providing greater flexibility for the overall schedule arrangement.

[0018] (2) In view of the complex nature of the concealed works inside the prestressed concrete tank wall, this invention effectively avoids the technical problem of the easy collision between steel bars, embedded steel plates and prestressed corrugated pipes in the limited pouring space by clarifying the construction and installation sequence and formulating avoidance principles. It also eliminates the construction stagnation caused by temporary on-site handling in traditional construction and ensures the rhythm of continuous slipform construction.

[0019] (3) This invention incorporates several precision control measures tailored to the construction characteristics of slipform: stiffening ribs are welded to the edges of the vertically embedded steel plates to enhance their lateral stiffness and ensure verticality; stiffening ribs with the same curvature are welded to the edges of the circumferentially embedded steel plates to enhance their lateral stiffness and ensure curvature; and the prestressed corrugated pipes are fixed with fixing ribs spaced apart along the length of the corrugated pipe. These methods are simple and effective, avoiding destructive repairs caused by misalignment or deformation, and ensuring construction efficiency.

[0020] (4) The avoidance rules described in this invention establish the highest priority protection principle for reinforcing bars and prestressed corrugated pipes. When various concealed engineering components have spatial conflicts, priority is given to ensuring that the designed positions of reinforcing bars and corrugated pipes are not disturbed, thereby ensuring the smooth progress of prestressed tensioning construction and effectively protecting the structural safety of the tank wall.

[0021] (5) This invention is not only applicable to prestressed concrete storage tanks, but can also be extended to the slipform construction of other reinforced concrete structures with dense reinforcement and complex embedded parts, and has good prospects for promotion and application and economic and social benefits. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the slipform system for the prestressed concrete storage tank wall according to an embodiment of the present invention; Figure 2 This is a side view of the vertically embedded steel plate in an embodiment of the invention. Figure 3 This is a top view of the circumferentially embedded steel plate in an embodiment of the invention. Figure 4 This is a side view of the horizontal prestressed corrugated pipe fixing structure according to an embodiment of the invention. Figure 5 This is a top view schematic diagram of the vertical prestressed corrugated pipe fixing structure according to an embodiment of the invention; Figure 6 This is a flowchart illustrating the slipform construction method for the prestressed concrete storage tank wall, as described in this invention embodiment.

[0023] In the diagram: 1. Steel formwork; 2. Enclosure; 3. Support frame; 4. Lifting frame; 5. Jack; 6. Support rod; 7. Platform steel beam; 8. Platform support; 9. Platform slab; 10. Platform railing; 11. Limiting buckle; 12. Vertical reinforcement of the wall; 13. Horizontal reinforcement of the wall; 14. Vertical prestressed corrugated pipe; 15. Horizontal prestressed corrugated pipe; 16. Vertical embedded steel plate; 17. Circumferential embedded steel plate; 18. Embedded steel plate studs; 19. Tank wall; 20. Stiffening rib; 21. Fixing rib. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0025] This embodiment uses a 20,000m... 3Taking a prestressed concrete cryogenic liquid ammonia storage tank as an example, the tank wall 19 has an inner diameter of 20m, a height of 22.6m (elevation 1.000~23.600), and a wall thickness of 0.6m with a uniform cross-section. Several small embedded steel plates for straight ladders, pipe supports, and other facilities are installed on the outer side of the tank wall 19; embedded steel plates are installed on the inner side of the tank wall 19, including three circumferential embedded steel plates 17 along the full circumference of the inner side of the tank wall 19 and 60 vertical embedded steel plates 16 from the bottom to the top of the wall; prestressed corrugated pipes are installed inside the tank wall 19, including 64 vertical prestressed corrugated pipes 14 and 44 rings of horizontal prestressed corrugated pipes 15. It should be noted that in this embodiment, the slipform construction only slides to an elevation of 22.400, and the tank wall concrete is poured to an elevation of 22.3 meters, where a horizontal construction joint is left. The remaining wall sections and eaves beams were constructed using the traditional formwork method due to their variable cross-sections and complex structures.

[0026] like Figure 1 As shown, the slipform construction method for the prestressed concrete storage tank wall in this embodiment includes the following steps: Step S1: Formwork System Assembly: After the concealed works (reinforcement binding, prestressed corrugated pipe and embedded steel plate installation) of the first formwork wall at the bottom of the storage tank are inspected and accepted, the slipform system is assembled. The slipform system includes a formwork system, a lifting system and a platform system. The concealed works in this step include reinforcement binding, prestressed corrugated pipe and embedded steel plate installation. Specifically, the following steps are included: (1) Template System. The template system includes a steel template 1, a surrounding ring 2, and a support frame 3. The height of the steel template 1 must match the single slipform stroke. In this embodiment, the height of the steel template 1 is 1.2m. The surrounding ring 2 is fixedly installed circumferentially on the outer side of the steel template 1 to ensure the curvature accuracy of the tank wall 19 during casting while fixing the steel template 1. The support frame 3 is fixed on the outer side of the steel template 1. When installing the steel template 1, the taper of the steel template 1 is strictly controlled, keeping the upper opening small and the lower opening large. The outer mold taper is 0.3%, and the inner mold taper is 0.5%.

[0027] (2) Lifting System. The lifting system includes a lifting frame 4, jacks 5, and support rods 6. The lifting frame 4 is arranged at equal intervals around the center of the tank wall 19, and its size matches the casting thickness of the tank wall 19 and the height of the steel formwork 1. The spacing of the lifting frame 4 is coordinated with the length of the circumferentially embedded steel plate 17. The lifting frame 4 is fixed together with the support frame 3. The jacks 5 are installed on the crossbeams of the lifting frame 4 and are evenly distributed around the circumference. The number of jacks 5 is increased accordingly at the buttress column positions. The support rods 6 are fixedly installed in the middle of the steel formwork 1 and are made of steel pipes. The support rods 6 are connected to the jacks 5 and serve as the track for the sliding formwork system to raise and lower, controlling the horizontal rise of the entire platform. Limit buckles 11 are installed on the upper part of the support rods 6 to limit the rising stroke of the jacks 5.

[0028] (3) Platform System. The platform system includes a cantilever construction platform and a suspended platform. The cantilever construction platform is arranged circumferentially along the inner and outer sides of the tank wall 19 and fixed to the lifting frame 4. The platform width meets the construction operation requirements; in this embodiment, the width is 1.6m. The cantilever construction platform includes a platform steel beam 7, a platform support 8, a platform plate 9, and a platform railing 10. The platform steel beam 7 is fixed to the lifting frame 4, and the platform plate 9 is laid on the platform steel beam 7. One end of the platform support 8 is fixed to the platform steel beam 7, and the other end is fixed to the lifting frame 4, providing support for the platform steel beam 7. A guardrail 10 of not less than 1.2m is fixedly installed around the platform steel beam 7 to ensure construction safety. The suspended platform is suspended below the cantilever construction platform and is used for surface finishing operations after concrete demolding. In this embodiment, the width of the suspended platform is 0.8m, and it is also equipped with guardrails 10 and toe boards around its perimeter.

[0029] Step S2, Initial Slipforming: After the concrete of the first formwork wall at the bottom of the storage tank is poured and reaches the demolding strength, a trial lift is performed and the slipforming system is thoroughly inspected. This includes the following steps: The initial slipforming is a trial slipforming process before continuous construction. After pouring the concrete for the first formwork wall at the bottom of the storage tank, all jacks 5 are simultaneously raised 5-10cm to test the concrete strength. If the concrete reaches the demolding strength, the steel formwork 1 is gradually slip-raised to a height of 400mm, while a comprehensive inspection of all lifting and formwork systems is conducted. The concrete demolding strength is controlled between 0.2 and 0.4 MPa.

[0030] Step S3, Continuous Slipforming: The concealed works are installed sequentially according to a preset order, coordinating the synchronous progress of each construction procedure. Specifically, when collisions occur between various wall reinforcement bars, prestressed corrugated pipes, and embedded steel plate studs (18), avoidance rules are followed, and precision control measures are implemented during installation. The preset order is: inner wall reinforcement binding, prestressed corrugated pipe installation, outer wall reinforcement binding, horizontal wall tie bar binding, circumferential embedded steel plate installation, and vertical embedded steel plate installation. This includes the following steps: Continuous slipforming is a continuous construction process that includes the slipforming of steel formwork 1, the installation of concealed works, concrete pouring and curing, and verticality testing.

[0031] (1) Normal slipforming. The time interval between each slipforming operation is determined based on the concrete setting time, ensuring that the concrete reaches the demolding strength. In this embodiment, the time interval is controlled at approximately 1.0 to 1.5 hours, and the controlled pouring height for each layer is 300 mm. To ensure slipforming synchronization, the position of the limit buckle on the support rod 6 is adjusted before each slipforming operation so that each jack 5 stops synchronously when it reaches that position.

[0032] During the slipforming process, the cantilever construction platform should be kept horizontal, the relative height difference between jacks 5 should not exceed 40mm, and the lifting difference between two adjacent jacks 5 should be controlled within 20mm.

[0033] When extending support rod 6, adjacent joints should be staggered, and the number of joints on the same horizontal section should not exceed 25% of the total number of rods. The joints should be socket-type connections, and the extended parts should be ground smooth to ensure that jack 5 can pass smoothly.

[0034] (2) Wall reinforcement binding. To ensure the accurate position of the vertical reinforcement 12 in the wall, circumferential positioning reinforcement is welded on the crossbeam of the lifting frame 4, and positioning rings are welded on the positioning reinforcement. The vertical reinforcement is then inserted into the positioning rings, which controls the reinforcement spacing and the thickness of the protective layer.

[0035] The positioning control of the horizontal reinforcement bars 13 in the wall can be achieved by marking the spacing lines on the vertical reinforcement bars in advance to control the binding spacing. A net distance of about 40cm should be maintained between the top of the steel formwork 1 and the horizontal beam of the lifting frame 4 to facilitate the insertion of the horizontal reinforcement bars 13 in the wall and to ensure that at least two binding horizontal reinforcement bars are visible on the concrete surface.

[0036] (3) Corrugated pipe installation. Prestressed corrugated pipes should be installed simultaneously with the reinforcement binding. After the prestressed corrugated pipes are installed to the predetermined positions, both the horizontal prestressed corrugated pipes 15 and 14 are fixed to the horizontal reinforcement bars 13 of the wall using fixing bars 21. The corrugated pipes and fixing bars 21 are tied together, such as... Figure 4 , Figure 5 As shown.

[0037] (4) Processing and installation of embedded steel plates. During processing, stiffening ribs 20 are welded to improve lateral stiffness and ensure the verticality of the vertical embedded steel plate 16 and the curvature of the circumferential embedded steel plate 17. The stiffening ribs 20 are made of unequal-sided angle steel L50×32×4, welded to both sides of the embedded steel plate in the width direction. During welding, the shorter limbs of the angle steel are welded and fixed to the inner surface of the steel plate, while the longer limbs are perpendicular to the plane of the steel plate. The openings of the angle steel on both sides face each other, both towards the inside of the steel plate. Each angle steel is approximately 120mm long and spaced 300mm apart, and the spacing must be coordinated with the spacing of the wall reinforcement to enhance lateral stiffness while avoiding collisions with the wall reinforcement.

[0038] Before installing the embedded steel plates, verify their position, elevation, and specifications, and mark them on the slipform platform. They must not be welded to the reinforcing bars. The studs 18 and stiffening ribs 20 of the embedded steel plates are inserted into the grid formed by the wall reinforcement. In case of collision, adjust the studs 18 and stiffening ribs 20 to ensure the wall reinforcement does not move. The weld seams connecting the vertical embedded steel plates 16 and the butt joints of the circumferential embedded steel plates 17 are staggered. During the slipforming process, any embedded parts and reserved holes that need to be chiseled out should be chiseled out promptly after demolding to avoid damaging the surface of the tank wall 19. Concrete should be poured symmetrically on both sides of the reserved openings. Due to the significant disturbance to the vertical embedded steel plates 16 caused by multiple processes, multiple checks should be performed after installation and positioning, and each steel formwork should be inspected after reinforcement. If excessive deformation is found, adjustments should be made promptly.

[0039] (5) Concrete construction. Before construction, concrete mix design tests are conducted according to the design requirements. The mix design parameters are adjusted based on factors such as slipform speed, local temperature, air humidity, and diurnal temperature range. Slipform speed directly affects construction quality and safety.

[0040] In this embodiment, based on meteorological conditions and construction schedule, and according to test results, the initial setting time of the concrete was appropriately advanced compared to the conventional mix design, while the final setting time was appropriately delayed. This ensured that the concrete did not stick to the formwork during the slipforming process, allowing for smooth slipforming, and that the wall reached its load-bearing strength after demolding. Concrete pouring was controlled at a slipforming rate of approximately 300mm every 1.0 to 1.5 hours, requiring 23m³ of concrete. 3 The daily slipform height is controlled at approximately 3 meters. Two 56-meter truck-mounted concrete pumps can meet the construction speed requirements. Ground transportation utilizes 8-meter... 3 Four concrete mixer trucks were used, and each truck took approximately 1.5 hours to make a round trip. The total amount of concrete used in the slipform construction was approximately 2000 cubic meters. 3 .

[0041] (6) Concrete surface treatment and curing. During the slipforming process, the concrete surface should be smoothed in a timely manner after demolding to maintain a clean appearance. When watering the concrete for curing, a high-pressure water pump connected to a hose should be used, and a designated person should patrol and water the concrete regularly.

[0042] (7) Verticality Measurement. Four measuring points are evenly distributed on the tank wall 19. A 10kg plumb bob is suspended from the bottom of the platform system at each point, and a crosshair is drawn on the ground as the measurement reference point. The verticality deviation of the tank wall 19 is judged by measuring the offset between the tip of the plumb bob and the reference point, combined with the distance between the plumb line and the tank wall 19. In this embodiment, the measurement is performed once every half shift or 1.5m of sliding height. If a deviation is found, it must be corrected in time.

[0043] Step S4, Final Slipforming: After the steel formwork has slipped to the preset elevation of the tank wall, slowly raise the steel formwork for free slipforming until the lower edge of the steel formwork reaches the top surface of the tank wall concrete. This specifically includes the following steps: The final slipforming stage refers to the construction phase where, when the slipform construction reaches the preset elevation of the tank wall 19, the formwork system is leveled and aligned, the platform is unloaded, and the steel formwork 1 is emptied. In this embodiment, the final slipforming stage begins when the steel formwork 1 is slipped to 1.0m below the designed top elevation of the tank wall 19.

[0044] First, slow down the slipforming speed while simultaneously performing a comprehensive leveling and alignment of the formwork system. The elevation adjustment and centering correction of the entire steel formwork 1 should be completed before slipforming to the final formwork, ensuring a uniform and continuous top structure and guaranteeing the accuracy and correct positioning of the tank wall 19's top elevation. After all concrete pouring is completed, promptly remove all loads that can be removed from the platform and continue raising the steel formwork 1 according to the continuous slipforming procedure until the lower edge of the steel formwork 1 reaches the top of the tank wall concrete, entering the no-load slipforming state. During the no-load slipforming process, use transverse reinforcing bars to connect each support rod 6 via spot welding for horizontal reinforcement. The vertical spacing of the transverse reinforcing bars is 600mm.

[0045] Step S5, System Dismantling: After the final section of the wall concrete reaches the preset strength, the lifting system, formwork system, and platform system are dismantled sequentially using a tower crane. This includes the following steps: System dismantling refers to the construction phase of dismantling the slipform system in stages and sections after the slipform construction is completed. In this step, the slipform system is dismantled after the concrete strength of the last formwork reaches 15MPa. Before dismantling, all machinery and materials on the platform are cleared, and all construction loads are removed. During dismantling, the lifting system is dismantled first, followed by the formwork system, and finally the platform system. In this embodiment, the platform system is cut into 6m sections, and the sections are lifted to the ground using a tower crane to complete the dismantling.

[0046] During dismantling, workers must wear safety belts and follow the established sequence, strictly prohibiting haphazard dismantling and disposal; dismantled parts and materials must be promptly moved to ensure the platform is free of excess load. Strict adherence to safety operating procedures is essential to ensure safe operation at heights.

[0047] This embodiment employs the aforementioned construction method, with the tank wall 19 completed in 20 days, saving approximately 30-40 days compared to traditional formwork construction. During construction, the positioning of embedded parts, the verticality of the tank wall 19, and its curvature were precisely controlled, resulting in a smooth, defect-free appearance for the tank wall 19, with all indicators meeting design requirements. No safety accidents occurred throughout the entire construction process. The method of this invention offers high construction efficiency, good overall integrity, and high installation precision.

[0048] It should be noted that the specific embodiments described in this specification are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various modifications, additions, or equivalent substitutions to the above embodiments, but all such changes should fall within the scope derived from the inventive concept. The scope of protection of this invention is determined by the claims; any equivalent changes or modifications made based on the spirit and essence of this invention should be covered within the scope of protection of this invention.

Claims

1. A slipform construction method for the wall of a prestressed concrete storage tank, characterized in that: Includes the following steps: S1. Template Assembly: After the concealed works of the first formwork wall at the bottom of the storage tank are inspected and accepted, the slipform system will be assembled. S2, Initial slipforming: After the concrete of the first formwork wall at the bottom of the storage tank is poured and reaches the demolding strength, a trial lift is carried out and the slipforming system is fully inspected. S3. Continuous slipforming: The concealed works are installed in sequence according to the preset order, and the various construction procedures are coordinated to proceed simultaneously. Among them, when various wall steel bars, prestressed corrugated pipes and embedded steel plate studs collide, the avoidance rules are followed, and precision control measures are implemented during construction and installation. S4. Final slide: After the steel formwork is slided to the preset elevation of the tank wall, the steel formwork is slowly raised to slide without load until the lower part of the steel formwork is raised to the top surface of the concrete of the tank wall. S5. System Dismantling: After the final section of the wall concrete reaches the preset strength, the slipform system is dismantled using a tower crane.

2. The slipform construction method according to claim 1, characterized in that: The slipform system includes a template system, a lifting system, and a platform system; (1) The formwork system includes steel formwork, a surrounding ring, and a steel formwork support frame; the surrounding ring is fixedly installed on the outer side of the steel formwork along the circumference; the steel formwork support frame 3 is fixed on the outer side of the steel formwork; (2) The lifting system includes jacks, lifting frames and support rods; the lifting frames are arranged at equal intervals along the circumference of the center of the tank wall, and the lifting frames and support frames are fixed together; the jacks are installed on the lifting frames and are evenly distributed along the circumference; the support rods are set in the middle of the steel template and are connected to the jacks. (3) The platform system is arranged circumferentially along the tank wall and fixed on the lifting frame.

3. The slipform construction method according to claim 2, characterized in that: Step S2 includes the following steps: initial slipforming is a trial slipforming process before continuous construction; after pouring the concrete for the first formwork wall at the bottom of the storage tank, all jacks are raised simultaneously to test the concrete strength; if the concrete reaches the demolding strength, the steel formwork is gradually slip-raised, and a comprehensive inspection of the lifting system and formwork system is carried out at the same time.

4. The slipform construction method according to claim 2, characterized in that: Step S3 includes the following steps: (1) Normal slipforming: The time interval between each slipforming is determined according to the concrete setting time, and it is necessary to ensure that the concrete reaches the demolding strength. To ensure the synchronization of slipforming, the position of the limit buckle on the support rod is adjusted before each slipforming, so that each jack stops synchronously when it is raised to that position. When the support rod is extended, adjacent joints are staggered, and the number of joints at the same horizontal section does not exceed 25% of the total number of rods. The joints adopt socket connection, and the extended part is ground smooth to ensure that the jacks can pass through smoothly. (2) Reinforcing steel reinforcement binding in the wall; (3) Corrugated pipe installation: Prestressed corrugated pipes should be installed at the same time as the steel bars are tied. After the prestressed corrugated pipes are installed in the predetermined position, both the horizontal and vertical prestressed corrugated pipes are fixed by lapping the fixing bars on the horizontal steel bars of the wall. The corrugated pipes and the fixing bars are tied together. (4) Processing and installation of embedded steel plates; (5) Concrete construction; (6) Concrete surface treatment and curing; (7) Verticality measurement: Several measurement points are evenly distributed on the tank wall. A plumb line is suspended from the bottom of the platform system and a cross line is drawn on the ground as the measurement reference point. The verticality deviation of the tank wall is judged by measuring the offset between the tip of the plumb line and the reference point, combined with the distance between the plumb line and the tank wall.

5. The slipform construction method according to claim 4, characterized in that: In step S3, the avoidance rules include: the positions of the tank wall reinforcement and prestressed corrugated pipe cannot be adjusted; when the prestressed corrugated pipe collides with the wall tie bar, the position of the tie bar is slightly adjusted; when the embedded steel plate studs, stiffening ribs collide with other concealed works, the positions of individual studs and stiffening ribs are adjusted.

6. The slipform construction method according to claim 5, characterized in that: In step S3, the precision control measures include: welding stiffening ribs on both sides of the vertical pre-embedded steel plate in the width direction to enhance its lateral stiffness and ensure verticality; welding stiffening ribs with the same curvature on both sides of the circumferential pre-embedded steel plate in the width direction to enhance its lateral stiffness and ensure curvature; and fixing the prestressed corrugated pipe with fixing ribs, which are arranged at intervals along the length of the corrugated pipe.

7. The slipform construction method according to claim 6, characterized in that: In step S3, before installing the embedded steel plate, check its position, elevation, and specifications, and mark it on the slipform platform. It must not be welded to the reinforcing bars. The studs and stiffening ribs of the embedded steel plate are inserted into the grid formed by the wall reinforcing bars. If a collision occurs, adjust the studs and stiffening ribs so that the wall reinforcing bars do not move. The weld seams of the vertical embedded steel plates are staggered from the butt joints of the circumferential embedded steel plates. During the slipforming process, the embedded parts and reserved holes that need to be chiseled out should be chiseled out in time after demolding to avoid damaging the surface of the tank wall. Since the vertical embedded steel plates are greatly disturbed by multiple processes, they should be checked multiple times after installation and positioning. After the steel formwork is reinforced, it should be checked one by one. If excessive deformation is found, it should be adjusted and dealt with in time.

8. The slipform construction method according to claim 6, characterized in that: In the wall reinforcement binding process of S3 To ensure the accurate positioning of the vertical reinforcement bars in the wall, circumferential positioning reinforcement bars are welded to the horizontal beam of the lifting frame, and positioning rings are then welded onto the positioning reinforcement bars. The vertical reinforcement bars are then fitted into the positioning rings, which controls the reinforcement bar spacing and the thickness of the protective layer. The positioning control of the horizontal reinforcement bars in the wall can be achieved by marking the spacing lines on the vertical reinforcement bars in advance to control the binding spacing. The net distance between the top of the steel formwork and the horizontal beam of the lifting frame is controlled to facilitate the insertion of the horizontal reinforcement bars in the wall and to ensure that at least two binding horizontal reinforcement bars are visible on the concrete surface.

9. The slipform construction method according to claim 2, characterized in that: Step S4 specifically includes the following steps: slowing down the slipforming speed while simultaneously performing a comprehensive leveling and alignment of the formwork system; the elevation adjustment and center correction of the entire steel formwork should be completed before slipforming to the last formwork to ensure a uniform and continuous top structure, guaranteeing the accuracy and correct position of the tank wall top elevation; after all concrete has been poured, the load that can be removed from the platform system should be promptly unloaded, and the steel formwork should continue to be raised according to the procedure of the continuous slipforming stage until the bottom of the steel formwork is raised to the top of the tank wall concrete, entering the empty slipforming state; during the empty slipforming process, transverse steel bars are used to connect each support rod by spot welding for transverse horizontal reinforcement.

10. The slipform construction method according to claim 2, characterized in that: Step S5 specifically includes the following steps: after the wall concrete reaches the preset strength, the slipform system is dismantled; before dismantling, all tools and materials on the platform are cleaned up and all construction loads are removed; during dismantling, the lifting system is dismantled first, then the formwork system is dismantled, and finally the platform system is dismantled; wherein, the platform system is cut and separated into sections, and the sections are lifted to the ground by a tower crane to complete the dismantling.

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