Post-tensioning method and structure of mass concrete prestressed cable
By using a duct structure connected by high-density polyethylene corrugated pipes and heat shrink tubing joints, the problems of duct displacement and blockage in the post-tensioning method of prestressed cables in large-volume concrete were solved, enabling efficient grouting and stable fixation of prestressed cables, thus improving construction quality and structural durability.
Patent Information
- Application Number
- CN202511579100.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-31
- Publication Date
- 2025-12-16
AI Technical Summary
The existing problems of duct blockage and displacement in the post-tensioning method of prestressed cables for large-volume concrete lead to construction difficulties and incomplete grouting.
High-density polyethylene corrugated pipes are used as ducts and grouting pipes, and connected by heat shrink tubing joints. Combined with positioning brackets and T-shaped heat shrink tubing joints, the duct path is accurate and the grouting is unobstructed. Special tensioning equipment is used to tension the prestressed cables and inject cement grout.
It effectively avoids duct displacement and blockage, improves grouting efficiency and compactness, and ensures the stability of prestressed cables and the durability of the structure.
Smart Images
Figure CN121138162A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of concrete construction, in particular to a post-tensioning method and structure of prestressed cable for mass concrete. BACKGROUND
[0002] Mass concrete will produce internal and external temperature difference due to cement hydration heat, and will shrink after cooling. Both of these two effects will produce tensile stress, which will cause cracks in concrete, affect structural stiffness and durability. By setting prestressed cable in mass concrete, the compressive stress applied by the prestressed cable can directly offset part of the tensile stress, preventing cracks from occurring or expanding. In structures such as bridges, dams, and large pipe corridors, prestressed cable can make the concrete structure bear greater load, while reducing the size of the structure section and saving materials.
[0003] The commonly used prestressed cable construction methods are pre-tensioning and post-tensioning. The post-tensioning method is to apply pre-compressive stress to the concrete by tensioning the prestressed cable after the mass concrete is poured and reaches the design strength. It can accurately control the structural stress, and the pressure can be directly transmitted to the stabilized component during tensioning, avoiding stress loss due to unhardened concrete. The post-tensioning method can flexibly arrange the cable hole and cable body direction according to the shape and stress demand of the mass concrete component. The tensioning process of the post-tensioning method is carried out after the concrete is poured, which will not conflict with the pouring and vibrating processes, and is suitable for large and complex concrete components.
[0004] In the prior art, before pouring the mass concrete, metal or plastic corrugated pipes are pre-buried at the designed positions to form the tensioning channel of the cable body. However, during construction, the pre-buried corrugated pipes may be damaged, causing blockage due to slurry leakage, and the steel reinforcement may collide with the corrugated pipes, causing deviation, which in turn leads to difficulties in cable threading and non-compact grouting. SUMMARY
[0005] To solve the problems of the prior art, the present application provides a post-tensioning method and structure of prestressed cable for mass concrete, which solves the problems of hole blockage and deviation in the existing post-tensioning method of prestressed cable for mass concrete.
[0006] To solve the above problems, the technical solution adopted by the present application is as follows: Step one, pre-buried hole and grouting pipe, high-density polyethylene corrugated pipe is used as the hole and grouting pipe, after the steel reinforcement frame and formwork are installed, the corrugated pipe is pre-buried along the designed path, and a positioning support is installed to position the corrugated pipe. The grouting pipe is pre-buried, the grouting pipe is connected with the hole, the both ends of the hole and the upper end of the grouting pipe are temporarily blocked, and the spiral reinforcement and anchor pad are pre-buried at both ends of the hole. Step two, pouring concrete, using concrete of the designed grade to pour, and vibrating the concrete to make it dense during pouring; Step three, maintenance and strength detection, using perchloroethylene resin plastic solution to spray on the concrete surface for maintenance, after the solution volatilizes, a thin film is formed on the concrete surface to isolate the concrete from the air, prevent the evaporation of water in the concrete to ensure the normal progress of cement hydration, after the completion of maintenance, the film can self-aging and fall off, and the concrete strength reaches more than 75% of the design value; Step four, threading and tensioning, threading the prestressed cable into the embedded hole, installing the anchor, clamping piece and limiting plate in the counterbore outside the anchor pad, threading the prestressed cable through the anchor at both ends, using special tensioning equipment to tension symmetrically according to the design sequence, the special tensioning equipment can use a jack, and the tensioning force and cable elongation are monitored during the tensioning process; Step five, anchoring, after the tension reaches the design value, i.e. the tension and cable elongation meet the requirements, the prestressed cable is fixed at the end of the component by the anchor; Step six, hole grouting and anchor sealing, removing the temporary plugging at both ends of the hole and the upper end of the grouting pipeline, injecting cement slurry into the hole through the grouting pipeline to fill the void in the hole, the grouting pipeline is connected with the middle part of the hole, the cement slurry moves from the middle part to both ends of the hole during the grouting process, and the hole is filled with cement slurry after the cement slurry is filled at both ends, and finally the anchoring end is treated by concrete anchor sealing.
[0007] Further, the corrugated pipe in step one is connected by a heat shrink tube joint, the heat shrink tube joint is connected with the corrugated pipe socket at both ends, the heat shrink tube joint is provided with a plug-in groove, the corrugated pipe is provided with a plug-in boss matched with the plug-in groove, and the heat shrink tube joint is sealed after heat shrinkage. After the hole is embedded, the two ends can be temporarily plugged with adhesive tape to prevent concrete from entering during concrete pouring.
[0008] Further, the positioning support in step one is a plurality of sleeves outside the corrugated pipe, the distance between adjacent two positioning supports is ≤50cm, and the positioning support is installed on the steel reinforcement frame by binding to ensure the accurate path and stable position of the corrugated pipe.
[0009] Further, the grouting pipeline in step one is connected with the middle part of the hole through a three-way heat shrink tube joint, the three-way heat shrink tube joint is connected with the hole in the horizontal direction, and the upper end of the grouting pipeline is reserved to be 1m-2m higher than the concrete surface. The upper end of the grouting pipeline can be temporarily plugged with adhesive tape to prevent concrete from entering the grouting pipeline during concrete pouring.
[0010] Further, in step two, the vibrating point is ≥10cm away from the corrugated pipe, and the through hole is drilled through the hole using a through hole device after the pouring is completed, and the diameter of the through hole device is 5mm-10mm larger than the diameter of the prestressed cable.
[0011] The mass concrete prestressed cable structure comprises a duct, a positioning support, a grouting pipeline, a prestressed cable and an anchor, the duct is connected by a plurality of high-density polyethylene corrugated pipes through a heat shrink pipe joint, the duct is installed on a steel reinforcement frame of the concrete through the positioning support, the grouting pipeline is communicated with the middle position of the duct through a tee heat shrink pipe joint, the prestressed cable is arranged in the duct, the prestressed cable is inserted into the duct after the concrete is poured, the prestressed cable is installed at both ends of the concrete member through the anchor, the concrete strength reaches more than 75% of the design specified value, and the prestressed cable is tensioned through a jack to apply a pre-pressure to the concrete, Further, the positioning support is in a U shape as a whole and is processed from a steel bar with a diameter of 12 mm, Further, the inner wall corner of the tee heat shrink pipe joint is a round corner transition, the flowability of the cement slurry is improved, and the grouting effect is improved, The beneficial effects of the scheme are as follows: compared with the prior art, the mass concrete prestressed cable post-tensioning method and structure adopt high-density polyethylene corrugated pipes as the duct and the grouting pipeline, have good damage resistance and cement slurry leakage resistance, the corrugated pipes are connected through heat shrink pipe joints, the interface has good sealing performance, the positioning support is used to position the corrugated pipes, the duct can be effectively prevented from deviating and being blocked, the grouting pipeline is connected with the middle part of the duct through a tee heat shrink pipe joint, and when the cement slurry is grouted, the cement slurry enters the duct through the grouting pipeline and moves from the middle part of the duct to both ends, so that the grouting efficiency can be effectively improved. BRIEF DESCRIPTION OF DRAWINGS
[0012] Figure 1 The flow chart of the mass concrete prestressed cable post-tensioning method of the application is shown in the figure; Figure 2 The mass concrete prestressed cable structure of the application is shown in the figure; Figure 3 The enlarged schematic view of A of the application is shown in the figure; Figure 2 The schematic view of the positioning support of the application is shown in the figure; Figure 4 The schematic view of the positioning support of the application is shown in the figure; In the figure, the duct 1, the positioning support 2, the grouting pipeline 3, the prestressed cable 4 and the tee heat shrink pipe joint 5. DETAILED DESCRIPTION
[0013] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.
[0014] The embodiments are shown in the accompanying drawings Figures 1 to 4The method for post-tensioning of mass concrete prestressed cable is shown and comprises the following steps: Step one, pre-burying hole 1 and grouting pipe 3, using high-density polyethylene corrugated pipe as hole 1 and grouting pipe 3, after the installation of reinforcing steel bar frame and formwork is completed, pre-burying corrugated pipe according to the designed path, and installing positioning support 2 to position the corrugated pipe, the positioning support 2 is a plurality of sleeves outside the corrugated pipe, the distance between two adjacent positioning supports 2 is ≤50 cm, which is installed on the reinforcing steel bar frame by binding, to ensure the accurate path and stable position of the corrugated pipe. Compared with the traditional metal corrugated pipe, the high-density polyethylene corrugated pipe has better anti-damage and anti-leakage capacity, and the interface of the high-density polyethylene corrugated pipe has good sealing performance. The use of positioning support 2 for positioning can effectively prevent the hole 1 from deviating. The pre-buried grouting pipe 3 is communicated with the hole 1, and the two ends of the hole 1 and the upper end of the grouting pipe 3 are temporarily blocked. The corrugated pipe is connected by a heat-shrinkable pipe joint, the two ends of the heat-shrinkable pipe joint are connected with the corrugated pipe socket, the heat-shrinkable pipe joint is provided with a plug-in groove, the corrugated pipe is provided with a plug-in boss matched with the plug-in groove, and the heat-shrinking sealing can ensure the sealing performance of the corrugated pipe. After the hole 1 is pre-buried, it can be temporarily blocked by using adhesive tape to prevent concrete from entering during pouring concrete. The grouting pipe 3 is communicated with the middle position of the hole 1 through a three-way heat-shrinkable pipe joint 5, and the upper end of the grouting pipe 3 can be temporarily blocked by using adhesive tape. The three-way heat-shrinkable pipe joint 5 is connected with the hole 1 in the horizontal direction. The upper end of the grouting pipe 3 is reserved with a height exceeding the concrete surface by 1 m-2 m. Spiral rib and anchor pad are pre-buried at both ends of the hole 1, and the outer side of the anchor pad is provided with a counterbore for installing anchorage devices; Step two, pouring concrete, using concrete with a designed label to pour, vibrating the concrete to make it dense during pouring, using plug-in vibrator and attached vibrator to vibrate, the vibration point is ≥10 cm away from the corrugated pipe, after pouring is completed, a through hole device is used to pass through the hole 1, the diameter of the through hole device is 5 mm-10 mm larger than the diameter of the prestressed cable 4, if blockage is found, it can be treated in time by using high-pressure water flushing or mechanical dredging; Step three, curing and strength detection, the large volume concrete has a large surface area, which is not convenient for watering and curing, a perchloroethylene resin plastic solution can be sprayed on the concrete surface for curing, after the solution volatilizes, a thin film is formed on the concrete surface to isolate the concrete from the air, prevent the evaporation of water in the concrete to ensure the normal cement hydration, after the curing is completed, the thin film can self-aging and fall off, and the concrete strength reaches more than 75% of the design value; Step four, cable threading and tensioning, the prestressed cable 4 is threaded into the pre-buried hole 1, the anchorage devices, clamps and limit plates are installed in the counterbores outside the anchor pads, the two ends of the prestressed cable 4 are threaded through the anchorage devices, and the special tensioning equipment (such as a jack) is used to symmetrically tension according to the design sequence, the tensioning force and cable elongation are monitored during the tensioning process to ensure that the design requirements are met; Step five, anchoring, tensioning to the design value, that is, when the tension and elongation of the cable meet the requirements, the prestressed cable 4 is fixed on the end of the component by the anchor, preventing the cable from rebounding and ensuring the stability of the pre-pressure; Step six, hole 1 grouting and anchoring, removing the temporary blockage at both ends of the hole 1 and the upper end of the grouting pipeline 3, injecting cement slurry into the hole 1 through the grouting pipeline 3 to fill the void in the hole 1, preventing the cable from rusting, since the length of the hole 1 in the mass concrete is large, the grouting pipeline 3 is connected to the middle position of the hole 1, and the cement slurry moves from the middle to both ends of the hole 1 during the grouting process, which can effectively improve the grouting efficiency. After the both ends of the hole 1 are filled with cement slurry, the grouting is completed, and finally the anchoring end is treated with concrete anchoring, since the anchor is installed in the counterbore on the anchor pad, only the counterbore needs to be blocked with concrete to achieve anchoring, without the need for secondary pouring.
[0015] The mass concrete prestressed cable structure comprises a hole 1, a positioning support 2, a grouting pipeline 3, a prestressed cable 4 and an anchor, the hole 1 is connected by a plurality of high-density polyethylene corrugated pipes through heat shrink pipe joints, the hole 1 is installed on the steel reinforcement frame of the concrete through the positioning support 2, the positioning support 2 is in the shape of U as shown in Figure 4 The grouting pipeline 3 is connected to the middle position of the hole 1 through a three-way heat shrink pipe joint 5, the inner wall of the three-way heat shrink pipe joint 5 is rounded at the corner to improve the flowability of the cement slurry and improve the grouting effect, the prestressed cable 4 is arranged in the hole 1, the prestressed cable 4 is inserted into the hole 1 after the concrete is poured, the both ends of the prestressed cable 4 are installed in the concrete components through the anchor, the concrete strength reaches more than 75% of the design value, and the prestressed cable 4 is tensioned by a jack to apply pre-pressure to the concrete.
[0016] The above is only an embodiment of the present application, and the specific structure and characteristics of the scheme are not described in detail. It should be noted that for those skilled in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should be considered as the protection scope of the present application, and these will not affect the effect and practicality of the patent. The protection scope claimed in this application should be subject to the content of its claims, and the specific implementation mode and the like in the specification can be used to explain the content of the claims.
Claims
1. A post-tensioning method for mass concrete prestressed cable, characterized in that it comprises the following steps: Step one, embedding hole and grouting pipe, using high-density polyethylene corrugated pipe as hole and grouting pipe, after the installation of reinforcement cage and formwork is completed, embedding corrugated pipe according to the designed path, installing positioning support to position the corrugated pipe, embedding grouting pipe, the grouting pipe is communicated with the hole, temporarily blocking the hole at both ends and the upper end of the grouting pipe, embedding spiral reinforcement and anchor pad at both ends of the hole; Step two, pouring concrete, using concrete of designed grade to pour, vibrating the concrete to make it dense during pouring; Step three, curing and strength detection, using perchloroethylene resin plastic solution to spray on the surface of the concrete for curing, waiting for the concrete strength to reach more than 75% of the designed value; Step four, cable threading and tensioning, threading the prestressed cable into the embedded hole, installing anchor, clamp and limiting plate in the hole outside the anchor pad, threading the both ends of the prestressed cable through the anchor, using special tensioning equipment to symmetrically tension according to the designed order, monitoring the tensioning force and cable elongation during tensioning; Step five, anchoring, after the tensioning reaches the designed value, i.e. the tensioning force and cable elongation meet the requirements, fixing the prestressed cable at the end of the component with the anchor; Step six, hole grouting and anchor sealing, removing the temporary blocking at both ends of the hole and the upper end of the grouting pipe, injecting cement slurry into the hole through the grouting pipe to fill the gap in the hole, the grouting pipe is communicated with the middle part of the hole, the cement slurry moves from the middle part of the hole to both ends during grouting, the hole is filled with cement slurry after the grouting is completed, finally, the anchoring end is treated for concrete anchor sealing. The corrugated pipe in step one is connected by heat shrink tube joint, the both ends of the heat shrink tube joint are connected with the bell and spigot of the corrugated pipe, the heat shrink tube joint is provided with a plug-in groove, the corrugated pipe is provided with a plug-in boss matched with the plug-in groove, and the heat shrink tube joint is sealed after heat shrinkage.
2. The method of post-tensioning of a mass concrete prestressed cable according to claim 1, characterized in that: The positioning support in step one is a plurality of sleeves outside the corrugated pipe, the distance between adjacent two positioning supports is ≤50 cm, and the positioning support is installed on the reinforcement cage by binding.
3. The method of post-tensioning of a mass concrete prestressed cable according to claim 1, characterized in that: The grouting pipe in step one is communicated with the middle part of the hole by three-way heat shrink tube joint, the three-way heat shrink tube joint is connected with the hole in horizontal direction, and the upper end of the grouting pipe is reserved to be 1 m-2 m higher than the surface of the concrete.
4. The method of post-tensioning of a mass concrete prestressed cable according to claim 1, characterized in that: The vibration in step two is performed by inserting type vibrator and attached type vibrator, the vibration point is ≥10 cm away from the corrugated pipe, and a through hole is formed in the hole after pouring by using a through hole device, the diameter of the through hole device is 5 mm-10 mm larger than the diameter of the prestressed cable.
5. The method of post-tensioning of a mass concrete prestressed cable according to claim 1, characterized in that: The hole, positioning support, grouting pipe, prestressed cable and anchor are included, the hole is a plurality of high-density polyethylene corrugated pipes connected by heat shrink tube joint, the hole is installed on the reinforcement cage of the concrete by the positioning support, the grouting pipe is communicated with the middle part of the hole by three-way heat shrink tube joint, the prestressed cable is arranged in the hole, the prestressed cable is threaded into the hole after pouring the concrete, and the both ends of the prestressed cable are installed on the both ends of the concrete component by the anchor.
6. A mass concrete prestressed cable structure, characterized by: The positioning support is U-shaped as a whole and is made of steel bars with a diameter of 12 mm.
7. A mass concrete pre-stressed cable structure according to claim 6, characterised in that: The inner wall of the three-way heat shrink tube joint is round corner transition.
8. The mass concrete pre-stressed cable structure of claim 6, wherein: