Prestressed construction method and device

Abstract

The application provides a prestress construction method and device, which comprises the following steps: embedding a flexible bag in a designed position of a prestress steel beam; filling fluid medium into the flexible bag to make the flexible bag expand and deform and support inside concrete; discharging the fluid medium in the flexible bag when the concrete solidifies and reaches expected requirements, so that the flexible bag is separated from the concrete; taking out the flexible bag to form a prestress beam hole; and placing the prestress steel beam in the prestress beam hole and anchoring and stretching.

Description

Technical Field

[0001] This invention relates to the field of solid building construction technology, specifically to a prestressed construction method and a prestressed construction device. Background Technology

[0002] The prestressing of prestressed reinforced concrete beams is divided into pre-tensioning and post-tensioning methods, depending on whether the tensioning occurs before or after concrete pouring. Post-tensioning requires pre-reserving ducts for prestressed steel strands at the prestressing placement location before concrete pouring.

[0003] In the post-tensioning construction of prestressed reinforced concrete beams, the prestressed steel strands can be placed into the prestressing ducts before concrete pouring. When the prestressing adopts a single-end tensioning process, the fixed end of the prestressed steel strand needs to be poured inside the concrete beam. This method is generally used and is referred to as the pre-threading process. Alternatively, the strands can be inserted into the prestressing ducts later. This method is generally used when the double-end tensioning process is adopted and is referred to as the post-threading process.

[0004] Currently, the methods for forming holes in the post-tensioning prestressed ducts are divided into the pre-embedded pipe hole forming method and the pre-embedded rubber rod extraction hole forming method. The relevant technologies and devices are described below.

[0005] 1. Hole-forming method for pre-embedded pipes

[0006] The principle of the pre-embedded pipe drilling method is that, before concrete pouring, usually during the reinforcement binding process, the pipe is fixed inside the reinforcement according to the prestressed design position. When the concrete is poured, the concrete is separated by the pipe, forming a channel inside the pipe. Currently, pipe materials commonly used are high-density polyethylene resin or polypropylene plastics, or low-carbon steel strips and other metal materials. Plastic corrugated pipes typically have a corrugation height of 4–5 mm and a corrugation spacing of 30–60 mm, while metal corrugated pipes typically have a corrugation height of 2.5 mm or 3 mm.

[0007] Disadvantages of the pipe drilling method: 1. Pipe materials must be invested at once and cannot be reused; 2. Plastic corrugated pipes have a wall thickness of 2.5mm or 3mm, while metal corrugated pipes generally have a wall thickness of 0.28mm to 0.4mm. During construction, they are easily punctured by sharp objects such as reinforcing bars, and are also easily burned by welding sparks and molten iron falling from hot cutting. Damage is not easily detected. During concrete construction, concrete slurry can flow into the pipe from the damaged opening, which can easily cause blockage and prevent the prestressed tendons from being inserted.

[0008] 2. Rubber rod extraction hole-forming method

[0009] The principle of the rubber rod extraction hole-forming method is that before concrete pouring, usually during the reinforcement binding construction, the rubber rod is fixed in the reinforcement according to the prestress design position. After the concrete has solidified to a certain strength, the rubber rod is pulled out from one end. Utilizing the principle that the rubber rod is stretched and elongated, and its radial dimension is reduced, the rubber rod is separated from the concrete. The rubber rod is slowly pulled out of the concrete, thereby forming the prestressed tendon installation hole.

[0010] The drawbacks of the rubber rod extraction method are as follows: 1. To ensure smooth extraction of the rubber rod, its surface must be smooth, and the hole wall formed by the extraction must be free of thread marks. After the grout solidifies, the connection between the grout and the hole wall is prone to slippage, resulting in poor overall load-bearing performance. 2. Extracting the rubber rod requires a large tensile force. If the rubber rod is damaged, it may break during extraction, potentially causing a safety accident. 3. Choosing the right time to extract the rubber rod is challenging. If extracted too early, the concrete may collapse, preventing the formation of prestressed ducts. If extracted too late, the concrete may adhere to the rubber rod, increasing the difficulty of extraction or even making it impossible to extract. Summary of the Invention

[0011] In view of the shortcomings of the prior art, the purpose of this invention is to solve one or more problems existing in the prior art. For example, one objective of this invention is to provide a technique for forming prestressed ducts using a gas (liquid) bladder in the post-tensioning method.

[0012] To achieve the above objectives, the present invention provides a prestressed construction method, the method comprising: pre-embedding a flexible bladder at a designed location on a prestressed steel strand; filling the flexible bladder with a fluid medium to cause it to expand and deform and be supported within the concrete; after the concrete has solidified and met the expected requirements, draining the fluid medium from the flexible bladder to detach it from the concrete; removing the flexible bladder to form a prestressed strand passage; and placing the prestressed steel strand within the prestressed strand passage, anchoring and tensioning it.

[0013] In an exemplary embodiment, the flexible capsule may include a flexible capsule wall, an inner cavity enclosed by the flexible capsule wall, and a medium input terminal communicating with the inner cavity.

[0014] In an exemplary embodiment, the flexible capsule may further include: an internal medium conduit, which is connected to the medium input end and arranged in the inner cavity along the length direction of the flexible capsule, wherein a plurality of conduit injection holes are formed on the wall of the internal medium conduit and the plurality of conduit injection holes are spaced apart from each other along the length direction of the internal medium conduit.

[0015] In an exemplary embodiment, the flexible capsule may further include a partition arranged radially along the flexible capsule and dividing the inner cavity of the flexible capsule into a plurality of inner chambers, the partition having a through hole for the internal medium conduit to pass through.

[0016] In an exemplary embodiment, one or more circumferential ribs may be provided on the outer wall of the flexible capsule, and the multiple circumferential ribs are spaced apart from each other along the length direction of the flexible capsule.

[0017] Another aspect of the present invention provides a prestressed construction device, the device may include: a flexible bladder for forming prestressed tendon channels inside concrete, the flexible bladder including a flexible bladder wall, an inner cavity surrounded by the flexible bladder wall and a medium input end communicating with the inner cavity, the medium input end being used to connect to a fluid medium supply unit to supply fluid medium into the inner cavity.

[0018] In an exemplary embodiment, the flexible capsule may further include: an internal medium conduit, which is connected to the medium input end and arranged in the inner cavity along the length direction of the flexible capsule, wherein a plurality of conduit injection holes are formed on the wall of the internal medium conduit and the plurality of conduit injection holes are spaced apart from each other along the length direction of the internal medium conduit.

[0019] In an exemplary embodiment, the flexible capsule may further include a partition arranged radially along the flexible capsule and dividing the inner cavity of the flexible capsule into a plurality of inner chambers, the partition having a through hole for the internal medium conduit to pass through.

[0020] In an exemplary embodiment, one or more circumferential ribs may be provided on the outer wall of the flexible capsule along the circumferential direction, and the multiple circumferential ribs are spaced apart from each other along the length direction of the flexible capsule.

[0021] In an exemplary embodiment, the device may further include: a fluid medium supply unit connected to the medium input end to supply fluid medium into the inner cavity of the flexible bladder, thereby causing the flexible bladder to expand and deform and be supported inside the concrete.

[0022] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0023] (1) Compared with plastic or metal corrugated tubes, air (liquid) bags can be reused multiple times, are green and low-carbon, and save costs.

[0024] (2) Compared with plastic or metal corrugated pipes, corrugated pipes are more difficult to inspect for damage and are not easy to detect. They are also prone to concrete slurry flowing into the pipe and blocking the pipe. When a gas (liquid) bladder is damaged, it will immediately deflate, which is obvious and easy to detect and deal with in a timely manner.

[0025] (3) Compared with rubber rods, air (liquid) bladders achieve separation by evacuating the internal air (liquid) and have less impact on the concrete hole wall.

[0026] (4) Compared with rubber rods, air (liquid) bladders do not require strong pulling and are safer;

[0027] (5) The air (liquid) bag device is simple and the pump equipment is conventional. It can be centrally and intelligently controlled through inflation pipelines, sensor deployment and information technology, laying a good foundation for access to digital infrastructure projects.

[0028] (6) Under my country’s existing industrial system, air (liquid) bag system devices are easy to implement, production costs are controllable, and the prospects for promotion and application are broad. Attached Figure Description

[0029] The above and other objects and features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0030] Figure 1 A schematic diagram of the structure of the flexible bladder of a prestressed construction device according to an exemplary embodiment of the present invention is shown.

[0031] Figure label:

[0032] 1-Valve, 2-Flexible bladder wall, 3-Internal medium conduit, 4-Separator, 5-Conduit injection port, 6-Inner chamber, 7-Circular rib. Detailed Implementation

[0033] The prestressed construction method and apparatus of the present invention will be described in detail below with reference to the accompanying drawings and exemplary embodiments.

[0034] It should be noted that terms such as "first" and "second" are merely for ease of description and distinction, and should not be interpreted as indicating or implying relative importance. Terms such as "upper," "lower," "inner," "outer," "left," "right," "middle," and "bottom" are merely for ease of description and to establish relative orientations or positional relationships, and do not indicate or imply that the component referred to must have that specific orientation or position.

[0035] One aspect of the present invention provides a prestressed construction method applicable to bridges, buildings, and other engineering projects. This prestressed construction method includes: pre-embedding a flexible bladder at the designed location of the prestressed steel strands; filling the flexible bladder with a fluid medium to cause it to expand and deform, supporting it within the concrete; after the concrete has solidified and met the expected requirements, draining the fluid medium from the flexible bladder to detach it from the concrete; removing the flexible bladder to form a prestressed strand passage; and placing the prestressed steel strands within the prestressed strand passage, anchoring and tensioning them.

[0036] The fluid medium can be gas or liquid, so the flexible capsule can also be called a gas (liquid) capsule.

[0037] This invention employs a post-tensioning and post-threading prestressed duct forming technology, proposing the use of gas (liquid) bladders as auxiliary devices for forming prestressed ducts in post-tensioned and post-threaded prestressed reinforced concrete beams. By evacuating the gas (liquid) inside the flexible bladder, it is easy to detach from the concrete, has little impact on the concrete duct wall, can be reused multiple times, and the gas (liquid) bladder will immediately deflate when damaged, which is visually obvious, easy to detect and deal with in a timely manner.

[0038] The following will describe in detail the post-tensioning prestressed construction device and process flow according to an exemplary embodiment of the present invention.

[0039] Figure 1 A schematic diagram of the structure of the flexible bladder of a prestressed construction device according to an exemplary embodiment of the present invention is shown.

[0040] An exemplary embodiment of the prestressed construction apparatus of the present invention includes a flexible bladder for forming prestressed tendon channels inside concrete.

[0041] like Figure 1 As shown, the flexible capsule may include a flexible capsule wall 2, an inner cavity enclosed by the flexible capsule wall, and a medium input end communicating with the inner cavity.

[0042] The medium input end is used to connect to the fluid medium supply unit to supply fluid medium into the inner cavity. The fluid medium can be gas or liquid; therefore, the flexible bladder can also be called a gas (liquid) bladder. In this embodiment, a valve 1, i.e., a gas (liquid) injection valve, can be provided at the medium input end to control the flow of fluid medium into the flexible bladder.

[0043] The flexible capsule can be elongated, and there can be two media input terminals, formed at opposite ends of the flexible capsule. However, the invention is not limited to this; the number of media input terminals can also be one or more, depending on the needs.

[0044] To ensure that the channels formed by the air (liquid) bladder meet the requirements of prestressed construction, the air (liquid) bladder design must meet or consider the following performance requirements: the flexible bladder can be made of materials such as rubber, polyurethane, or composite fabric that can achieve full support when inflated or filled with liquid; the flexible bladder must have excellent wear resistance and puncture resistance; the flexible bladder must have a small expansion amount when fully inflated to the design air (liquid) pressure; and the flexible bladder must have controllable deformation at the stress point after local stress.

[0045] The flexible capsule may also include an internal medium conduit 3, which is connected to the medium input end and is arranged in the inner cavity along the length of the flexible capsule. Multiple conduit injection holes 5 are formed on the wall of the internal medium conduit, and the multiple conduit injection holes are spaced apart from each other along the length of the internal medium conduit.

[0046] The flexible capsule also includes a partition 4, which is arranged radially along the flexible capsule and divides the inner cavity of the flexible capsule into multiple inner chambers 6. That is, the flexible capsule can be compartmentalized, but the present invention is not limited thereto, and the flexible capsule may also be uncompartmentalized.

[0047] The separator 4 has a through hole for the internal medium conduit 3 to pass through. For example... Figure 1 As shown, the flexible bladder has a circular cross-section, and the partition is also circular and arranged along the cross-section of the flexible bladder. A through hole is formed at the center (center of the circle) of the partition 4. One end of the internal medium conduit 3 is connected to the medium input end, and the other end passes through the through hole and extends longitudinally through the inner cavity of the flexible bladder to deliver the medium to various parts inside the flexible bladder.

[0048] One or more circumferential ribs 7 are provided on the outer wall of the flexible bladder along the circumferential direction. The multiple circumferential ribs 7 are spaced apart from each other along the length of the flexible bladder, for example, evenly spaced. The design of the circumferential ribs 7 can simulate the corrugations of a bellows, so that the inner wall of the prestressed duct forms threads.

[0049] The device may also include a fluid medium supply unit connected to the medium input end to supply fluid medium into the inner cavity of the flexible bladder, thereby causing the flexible bladder to expand and deform and be supported inside the concrete.

[0050] Here, the medium can be a liquid medium. The amount of liquid introduced can be freely adjusted according to the required pressure under actual working conditions, thereby changing the degree of deformation of the flexible bladder to achieve the effects of support and pipe forming. However, the invention is not limited to this; other media such as gas can also be used, as long as they can fill the sealed cavity of the flexible bladder and cause the flexible bladder to expand and deform.

[0051] The fluid medium supply unit can use conventional pump equipment, and can also achieve centralized intelligent control through air supply lines, sensor deployment, and information technology.

[0052] One of the innovations of this invention lies in the design of the air (liquid) bladder, exploring the overall design parameter requirements of the air (liquid) bladder, and forming a usable air (liquid) bladder system device. Compared with related technologies, the prestressed construction device according to an exemplary embodiment of this invention has the following advantages:

[0053] (1) Compared with plastic or metal corrugated pipes, air (liquid) bladders can be reused multiple times, are green and low-carbon, and save costs; (2) Compared with plastic or metal corrugated pipes, corrugated pipes are difficult to inspect for damage and are not easy to detect. They are prone to concrete slurry flowing into the pipe and blocking the pipe. Air (liquid) bladders will immediately deflate when damaged, which is obvious and easy to detect and deal with in time; (3) Compared with rubber rods, air (liquid) bladders can be separated by evacuating the internal air (liquid) and have little impact on the concrete hole wall; (4) Compared with rubber rods, air (liquid) bladders do not require strong pulling and are safer; (5) Air (liquid) bladder devices are simple and pump equipment is conventional. They can be centrally and intelligently controlled through inflation pipelines, sensor deployment and information technology, which lays a good foundation for accessing digital infrastructure projects; (6) Under my country's existing industrial system, air (liquid) bladder system devices are easy to implement, production costs are controllable, and the prospects for promotion and application are broad.

[0054] The second innovation of this invention is that it proposes a method for forming prestressed ducts in post-tensioned prestressed reinforced concrete beams using air (liquid) bladders.

[0055] Specifically, another aspect of the present invention provides a prestressed construction method, the method comprising: pre-embedding a flexible bladder at a designed location on the prestressed steel strand; filling the flexible bladder with a fluid medium to cause it to expand and deform, supporting it within the concrete; after the concrete has solidified and met the desired requirements, draining the fluid medium from the flexible bladder to detach it from the concrete; removing the flexible bladder to form a prestressed steel strand passage; and placing the prestressed steel strand within the prestressed steel strand passage, anchoring and tensioning it. The prestressed steel strand can be a prestressed steel wire.

[0056] In an exemplary embodiment, the prestressed construction method of the present invention employs the prestressed construction apparatus as described above.

[0057] Method Principle: Post-tensioned prestressed reinforced concrete beam construction requires the formation of ducts of a specific size at the designed locations of the prestressed steel strands. According to the duct dimensions, elongated air (liquid) bladders are manufactured. External air (liquid) valves are installed at the ends of the bladders. The bladders are fully inflated through these valves. During concrete pouring, the inflated air (liquid) bladders provide good support within the concrete. After the concrete has solidified to a certain strength, the air (liquid) is extracted from the bladders through the valves at the ends. The bladders contract, forcing them to detach from the concrete. The bladders are then removed from the ducts, forming the ducts for the prestressed steel strands.

[0058] This invention uses a gas (liquid) bladder to achieve post-tensioning and post-threading prestressed duct formation. The device is simple, easy to implement, and the production cost is controllable.

[0059] Although the prestressed construction method and apparatus of the present invention have been described above in conjunction with exemplary embodiments, those skilled in the art should understand that various modifications and changes can be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined by the claims.

Claims

1. A prestressed construction method, characterized in that, The method includes: The flexible bladder is pre-embedded at the designed location of the prestressed steel strand; A fluid medium is injected into the flexible bladder to cause it to expand and deform, and to be supported inside the concrete. Once the concrete has solidified and met the expected requirements, the fluid medium inside the flexible bladder is discharged to detach the flexible bladder from the concrete. The flexible capsule is removed to form a prestressed through-hole; and The prestressed steel strands are placed in the prestressed strand passages, anchored, and tensioned. The flexible capsule includes a flexible capsule wall, an inner cavity enclosed by the flexible capsule wall, and a medium input end communicating with the inner cavity; the flexible capsule also includes an internal medium conduit, which communicates with the medium input end and is arranged in the inner cavity along the length direction of the flexible capsule, and a plurality of conduit injection holes are formed on the wall of the internal medium conduit, and the plurality of conduit injection holes are spaced apart from each other along the length direction of the internal medium conduit.

2. The prestressed construction method according to claim 1, characterized in that, The flexible capsule further includes a separator arranged radially along the flexible capsule and dividing the inner cavity of the flexible capsule into multiple inner chambers. The separator has a through hole for the internal medium conduit to pass through.

3. The prestressed construction method according to claim 2, characterized in that, One or more circumferential ribs are provided on the outer wall of the flexible capsule, and the multiple circumferential ribs are spaced apart from each other along the length of the flexible capsule.

4. A prestressed construction device, characterized in that, The device includes: a flexible bladder for forming prestressed tendon channels inside concrete; the flexible bladder includes a flexible bladder wall, an inner cavity enclosed by the flexible bladder wall, and a medium input end communicating with the inner cavity; the medium input end is used to connect to a fluid medium supply unit to supply fluid medium into the inner cavity; the flexible bladder further includes: an internal medium conduit, the internal medium conduit communicating with the medium input end and arranged in the inner cavity along the length direction of the flexible bladder; the wall of the internal medium conduit has multiple conduit injection holes spaced apart from each other along the length direction of the internal medium conduit.

5. The prestressed construction device according to claim 4, characterized in that, The flexible capsule further includes a separator arranged radially along the flexible capsule and dividing the inner cavity of the flexible capsule into multiple inner chambers. The separator has a through hole for the internal medium conduit to pass through.

6. The prestressed construction device according to claim 4, characterized in that, One or more circumferential ribs are provided on the outer wall of the flexible capsule, and the multiple circumferential ribs are spaced apart from each other along the length of the flexible capsule.

7. The prestressed construction device according to claim 4, characterized in that, The device further includes a fluid medium supply unit connected to the medium input end to supply fluid medium into the inner cavity of the flexible bladder, thereby causing the flexible bladder to expand and deform and be supported inside the concrete.

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