A bottom-support-free structure and construction method for early sealing of post-pouring strips in basement roof slabs

Abstract

This invention belongs to the field of construction of post-cast strips in basement roof slabs, and discloses a bottom-support-free structure and construction method for early closure of post-cast strips in basement roof slabs. The structure includes templates on both sides of the post-cast strip and a row of tie rods pre-embedded in the basement roof slab along the direction of the post-cast strip. A precast cover plate is installed on the post-cast strip, with concrete pouring holes on the precast cover plate. L-shaped water-retaining sills are installed on the main beams on both sides of the post-cast strip along the direction of the post-cast strip. Two load-bearing I-beams are installed side-by-side on the L-shaped water-retaining sills. A load-bearing channel steel is installed directly above the tie rods. U-shaped hinges, T-shaped tie rods, tie rods, load-bearing channel steel, and load-bearing I-beams are connected by nuts to form an upward-pull-up support system. A row of connectors is pre-embedded at intervals along the direction of the post-cast strip at the bottom of the templates, and the bottom template is installed on the connectors. This invention provides an upward-pull-up support system in the roof slab that can overcome the effects of structural settlement or temperature expansion and contraction, achieving early closure of the post-cast strip.

Description

Technical Field

[0001] This invention relates to the field of post-cast strip construction for basement roof slabs, and specifically to a bottom-support-free structure and construction method for early sealing of post-cast strips in basement roof slabs. Background Technology

[0002] In current building construction, especially in the construction of high-rise buildings and large-foundation basement structures, post-cast strips are a key technical measure for controlling structural cracks and resolving settlement differences. Based on their function, they are mainly divided into temperature expansion joints and settlement joints. According to design specifications and construction process requirements, temperature expansion joints typically need to be sealed at least 60 days after concrete pouring, while settlement joints can only be poured after the main structure of the high-rise building is topped out and settlement monitoring data stabilizes. While these strict time constraints ensure structural safety, they also bring significant time pressure and construction inconvenience to on-site construction.

[0003] Traditional construction methods for post-cast strips in basement roof slabs have the following significant technical drawbacks in order to ensure the structural stability of the cantilever beams and slabs on both sides of the post-cast strip and prevent deformation or deflection due to stress concentration: 1. Long usage period for reusable materials and high construction costs: Due to the delayed closure of the post-cast strip, the independent support frame at its bottom needs to be retained for a long time (sometimes as long as six months to more than a year) after the formwork in other areas of the main structure is removed, and cannot be reused. This directly leads to a huge increase in the rental costs of reusable materials such as steel pipes, fasteners, and formwork, significantly raising the overall construction cost of the project.

[0004] 2. Hinders construction flow and affects the overlap of work processes: The long-standing base support system severely occupies the working space in the basement and cuts off horizontal transportation channels. This makes it impossible to promptly insert subsequent work processes such as basement roof waterproofing, earthwork backfilling, basement interior decoration and renovation, and equipment and pipeline installation, creating "island" operations, greatly reducing construction efficiency, and making it difficult to achieve the three-dimensional cross-operation and rapid construction goals advocated by modern construction technology.

[0005] 3. Inconvenient construction and safety hazards: Independent support scaffolding needs to be erected separately, which not only results in low construction efficiency, but also the stability of the scaffolding may decrease due to external factors during the long-term idle period of the post-pouring strip. At the same time, the prolonged exposure of the post-pouring strip makes it easy for debris and garbage to fall in, and even rainwater to accumulate. This not only makes cleaning difficult, but may also cause steel reinforcement corrosion, affecting the final connection quality of the post-pouring strip.

[0006] 4. Restricting site utilization and affecting overall layout: For projects with large basements, the presence of post-pouring strips prevents timely backfilling of the roof slab. The construction site is often divided into multiple areas, making it impossible to form a complete circular road or an effective material storage yard, which brings great difficulties to on-site civilized construction and overall layout management.

[0007] In summary, traditional post-cast strip construction techniques, due to their inherent "waiting" and "supporting" patterns, have become a common technical bottleneck hindering the early closure of basement roof slabs, early backfilling of earthwork, and early integration of subsequent construction processes. Therefore, developing a bottom-support-free structure that can replace traditional bottom supports, achieve early closure of post-cast strips safely and reliably, has urgent and practical application value for shortening construction periods, reducing rental costs, and optimizing construction processes. Summary of the Invention

[0008] The purpose of this invention is to provide a bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs. This structure includes setting an upward-pull-type support system on the roof slab to overcome the effects of structural settlement or temperature expansion and contraction. At the same time, a support-free formwork system is also used when pouring concrete for the post-pouring strip, eliminating the need for bottom support. Without affecting the quality of the post-pouring strip, the traditional bottom support system is eliminated, and the early sealing of the post-pouring strip is achieved.

[0009] Another objective of this invention is to provide a construction method for a bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs. This method not only ensures a waterless working environment in the basement and improves safe and civilized construction conditions, but also frees up bottom space, allowing backfilling, pipeline installation, and other processes to be carried out in advance, significantly shortening the construction period and reducing construction costs.

[0010] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a construction method for a bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs, comprising the following steps: Step 1: When setting up the formwork for the post-pouring strip, a row of connectors is pre-embedded at intervals along the direction of the post-pouring strip at the bottom of the formwork on both sides. The additional reinforcement is fixed to the connectors in a cross shape, and the additional reinforcement is connected to the main steel reinforcement of the bottom structure. Step 2: Before pouring the concrete for the basement roof slab, embed a row of tie rods 15cm on each side of the post-pouring strip according to the cyclical pattern of main beam, mid-span, main beam, mid-span along the direction of the post-pouring strip. Step 3: Chisel and clean the post-pouring strip, and install precast cover plates, with concrete pouring holes set at the precast cover plates every 3 meters. Step 4: After the precast cover plate is sealed, the waterproof membrane of the basement roof slab is laid. After the waterproof membrane of the roof slab is completed, an L-shaped water retaining sill is added on the main structural beams on both sides of the post-pouring strip along the direction of the post-pouring strip, and then the waterproof protective layer is poured. Step 5: Referring to the position of the tie rods pre-embedded in the structural slabs on both sides of the post-pouring strip, place two load-bearing I-beams side by side on the L-shaped water retaining sills on both sides of the post-pouring strip, with a net distance of 20cm between the two load-bearing I-beams. Step 6: Place a 40cm long bearing channel steel directly above the pre-embedded tie rod. The groove of the bearing channel steel is perpendicular to the load-bearing I-beam with the groove facing downwards. There are reserved holes on the web of the bearing channel steel. Step 7: Connect the U-shaped hinge, T-shaped tie rod, tie rod, load-bearing channel steel, and load-bearing I-beam with nuts to form an upward-pull-up support system; Step 8: After the upper tensioning system is formed and the structural concrete reaches the required strength, remove all bottom formwork supports; Step 9: After the post-pouring strip has met the sealing requirements, install the bottom formwork on the pre-embedded connector at the bottom to ensure that the entire formwork system fits snugly with the structure. Step 10: After the bottom formwork system is formed, pour concrete through the upper reserved pouring hole. Finally, after the concrete pouring surface is flush with the reserved steel pipe pouring port, seal the pouring port and reinforce it with a waterproof protective layer.

[0011] Optionally, in step 1, the spacing between the pre-embedded connectors is 60~80cm; the connectors are pre-embedded sleeves or support screws.

[0012] Optionally, in step 3, the thickness of the precast cover plate is 7cm; the concrete pouring hole is formed by pre-embedding a 25cm high, 15cm diameter steel pipe with a water-stop flange and a pipe thread at the top of the pipe inside the precast cover plate during the casting process.

[0013] Optionally, in step 4, the L-shaped water barrier is 25cm high, and a 5cm diameter plastic pipe is pre-embedded every 10 meters inside the L-shaped water barrier as a drainage hole, and the drainage hole is sloped at 5% towards the drainage direction.

[0014] Optionally, in step 5, the length of the load-bearing I-beam is slightly shorter than the net distance of the L-shaped water retainer by 2cm; in step 7, the T-shaped tie rod is composed of a 50cm long lead rod with an outer diameter of 25mm at the top and a 15cm long lead rod with an outer diameter of 25mm at the middle.

[0015] Optionally, in step 7, the U-shaped component is formed by fixing two 15cm×10cm×3cm iron blocks to both sides of a 10cm×10cm×3cm iron block, and holes are opened on three sides of the U-shaped component to form a U-shaped hinge.

[0016] Furthermore, when the pre-embedded connector is a pre-embedded sleeve, the bottom template includes a support screw and a main keel installed in the pre-embedded sleeve, and a secondary keel and a panel template installed on the main keel.

[0017] Furthermore, when the pre-embedded connector is a formwork support screw, the bottom template includes a support rib installed on the formwork support screw and an intermediate rib plate installed.

[0018] Furthermore, the supporting rib is assembled from 1cm thick aluminum profiles, and connection holes are provided at the bottom and side ribs of the supporting rib; the reinforcing plate is assembled from a 1cm thick load-bearing plate and 5cm wide and 1cm thick reinforcing ribs, and connection holes are provided on all four side ribs.

[0019] A bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs includes templates on both sides of the post-pouring strip, and a row of tie rods pre-embedded in the basement roof slab along the direction of the post-pouring strip. A precast cover plate is provided on the post-pouring strip, and a concrete pouring hole is provided on the precast cover plate at each position every 3 meters. A waterproof roof slab membrane is laid on the basement roof slab and the precast cover plate. L-shaped water-retaining sills are installed on the main beams on both sides of the post-cast strip along the direction of the post-cast strip. Two load-bearing I-beams are installed side by side on the L-shaped water-retaining sills at the location of the tie rod. A load-bearing channel steel is installed directly above the tie rod, with the groove of the load-bearing channel steel pointing downwards and perpendicular to the load-bearing I-beams. The U-shaped hinge, T-shaped tie rod, tie rod, load-bearing channel steel, and load-bearing I-beams are connected by nuts to form an upward-pull-up support system. A row of connectors is pre-embedded at 60-80cm intervals along the direction of the post-pouring strip at the bottom of the template, and the bottom template is installed on the connectors.

[0020] The technical problem solved by this invention is the problem of the poor basement environment caused by the long-term inability to seal the post-pouring strip: In traditional construction, the post-pouring strip is exposed for a long time, and the surface water seepage causes water accumulation and dampness in the basement, steel corrosion, and poor construction. This invention ensures a dry working environment in the basement by sealing the top surface in advance.

[0021] Secondly, the long-term occupation of the bottom support affects subsequent construction: traditional processes require the retention of a large number of independent support frames, which hinders the overlapping construction of interior decoration and equipment installation in the basement. This invention adopts a bottom-support-free structure, which completely frees up the basement space and realizes three-dimensional cross-operation.

[0022] Thirdly, the problem of delayed earthwork backfilling caused by the inability to close the top slab: Traditional methods leave gaps in the top slab, which prevents outdoor processes such as earthwork backfilling and pipeline laying from being carried out in a timely manner. This invention achieves early slab closure by using prefabricated cover plates, creating conditions for early insertion of outdoor projects, thereby significantly shortening the overall construction period.

[0023] The bottom-support-free structure provided by this invention includes an upward-pull-type support system on the top slab that can overcome the effects of structural settlement or temperature expansion and contraction deformation. Specifically, the tying system is a hinged system. The load-bearing I-beams and channel steels are horizontally unrestrained, which can ensure the horizontal deformation requirements due to temperature contraction. At the same time, the I-beams rest on the main structural beams and can deform vertically in accordance with structural settlement. The cantilever slab and the I-beams are a vertically relatively stable system, so the cantilever slab can ensure synchronous deformation with the main structure. Therefore, this system also overcomes the settlement deformation requirements of the main structure. In summary, this support system not only eliminates the need for bottom support but also overcomes the requirements of temperature and settlement deformation. After cleaning the post-pouring strip, the precast concrete cover plate is hoisted to form a closed top surface in advance, and subsequent construction can be carried out under the protection of the cover plate. At the same time, the post-pouring strip concrete pouring also adopts a support-free formwork system, which also eliminates the need for bottom support. This invention eliminates the traditional bottom support system without affecting the quality of the post-pouring strip, enabling the early closure of the post-pouring strip. This not only ensures a waterless working environment in the basement and improves safe and civilized construction conditions, but also frees up bottom space, allowing backfilling, pipeline installation, and other processes to be carried out in advance, significantly shortening the construction period and reducing construction costs.

[0024] The beneficial effects of this invention are: According to the above technical solution, this invention adopts a convenient construction method, which significantly shortens the construction period and achieves rapid construction. First, by prefabricated cover plates sealing the top slab post-pouring strip in advance, earthwork backfilling, outdoor pipeline network and greening projects can be started in advance; at the same time, the interior decoration of the basement, equipment installation and other processes are no longer affected by the bottom support, realizing three-dimensional cross-operation and greatly shortening the overall construction cycle.

[0025] Secondly, the elimination of bottom support reduces construction costs: There is no need to erect or retain independent formwork support frames for a long time, which completely frees up turnover materials such as steel pipes and fasteners, saving a lot of rental fees and labor costs for erection and dismantling, resulting in significant overall economic benefits.

[0026] Third, it ensures a water-free environment and improves civilized construction: After the post-pouring strip is sealed in advance, it effectively blocks the seepage channels of surface water, ensures that the basement is in a dry state for a long time, avoids steel corrosion and water accumulation in the foundation pit, and makes the construction site clean and orderly, greatly improving the image of safe and civilized construction.

[0027] Fourth, the construction is simple and efficient, and the quality and safety are reliable. Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of Embodiment 2 of the present invention; Figure 2 This is a side cross-sectional view of Embodiment 2 of the present invention; Figure 3This is a schematic diagram of the structure of Embodiment 3 of the present invention; Figure 4 This is a side cross-sectional view of Embodiment 3 of the present invention; Figure 5 This is an enlarged schematic diagram of the prefabricated cover plate of Embodiment 2 or Embodiment 3 of the present invention; Figure 6 This is a schematic diagram of the pouring port cover plate of Embodiment 2 or Embodiment 3 of the present invention. Figure 1 ; Figure 7 This is a schematic diagram of the pouring port cover plate of Embodiment 2 or Embodiment 3 of the present invention. Figure 2 ; Figure 8 This is a schematic diagram of the ribbed plate in Embodiment 3 of the present invention. Figure 1 ; Figure 9 This is a schematic diagram of the ribbed plate in Embodiment 3 of the present invention. Figure 2 ; Figure 10 Schematic diagram of the support rib in Embodiment 3 of the present invention Figure 1 ; Figure 11 Schematic diagram of the support rib in Embodiment 3 of the present invention Figure 2 ; Figure 12 This is a schematic diagram of the pin in Embodiment 3 of the present invention.

[0029] Among them, 1. Nut, 2. T-shaped tie rod, 3. Bearing channel steel, 4. Load-bearing I-beam, 5. L-shaped water retaining sill, 6. Main reinforcement, 7. Structural column, 8. U-shaped hinge, 9. Steel pipe, 10. Precast cover plate, 11. Waterproof protective layer, 12. Drain hole, 13. Tie rod, 14. Water-stop steel plate, 15. Post-pouring strip, 16. Panel, 17. Secondary keel, 18. Main keel, 19. Embedded sleeve, 20. Formwork support rod, 21. Structural plate, 22. Main structural beam, 23. Water-stop flange, 24. Pipe thread, 25. Top slab waterproof membrane, 26. Reserved hole, 27. Reinforcing rib, 28. Load-bearing plate, 29. Connecting plate, 30. Ribbed plate, 31. Pin, 32. Wedge, 33. Support rib, 34. Connecting hole. Detailed Implementation

[0030] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0031] Example 1: A bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs, such as... Figures 1 to 9As shown, the structure includes formwork on both sides of the post-pouring strip 15, and a row of tie rods 13 pre-embedded at 15cm intervals on both sides of the post-pouring strip 15 along the direction of the post-pouring strip 15. A 7cm thick precast cover plate 10 is installed on the post-pouring strip, and concrete pouring holes are provided on the precast cover plate 10 at each position every 3 meters. A waterproof membrane 25 is laid on the basement roof slab and the precast cover plate 10. An L-shaped water retaining sill 5 is installed on the longitudinal main beam of the nearest structural column 7 on both sides of the post-pouring strip 15 along the direction of the post-pouring strip 15. Two load-bearing I-beams 4 are installed side by side on the L-shaped water retaining sill 5 at the position of the tie rod 13; a bearing channel steel 3 is installed directly above the tie rod 13, with the groove of the bearing channel steel 3 pointing downwards and perpendicular to the load-bearing I-beams 4; the U-shaped hinge 8, T-shaped tie rod 2, tie rod 13, bearing channel steel 3, and load-bearing I-beams 4 are connected by nuts 1 to form an upward-pull-up support system; a row of connectors is pre-embedded at 60~80cm intervals along the direction of the post-pouring strip 15 at the bottom of the template, and the bottom template is installed on the connectors.

[0032] Example 2: A construction method for a bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs, such as... Figure 1 , Figure 2 , Figure 5 , Figure 6 , Figure 7 As shown, it includes the following steps: Step 1: When setting up the formwork for the post-pouring strip 15, embed a row of embedded sleeves 19 with an inner diameter of 14mm at a spacing of 60~80cm at the bottom of the formwork on both sides along the direction of the post-pouring strip 15. One side of the embedded sleeve 19 is tightly attached to the bottom formwork, and the other side is sealed. The additional reinforcement is welded to the embedded sleeve 19 in a cross shape. The additional reinforcement is also welded to the intersection of the bottom structural main reinforcement 6 to form a reliable connection.

[0033] Step 2: Before pouring the concrete for the basement roof slab, embed a row of tie rods 13 with an outer diameter of 25mm at 15cm on both sides of the post-pouring strip 15, following the cyclical pattern of main beam, mid-span, main beam, mid-span, along the direction of the post-pouring strip 15. Step 3: Chisel and clean the waterstop steel plates 14 and the concrete surfaces on both sides of the post-cast strip 15, and install 7cm thick precast cover plates 10. Concrete pouring holes are provided in the precast cover plates 10 every 3 meters. These holes are formed by pre-embedding a 25cm high, 15cm diameter steel pipe 9 with a waterstop flange 23 and a pipe thread 24 at the top of the pipe within the precast cover plate 10 during the precast cover plate casting process. The pipe thread 24 can be used to tighten the cover plate.

[0034] Step 4: After the precast cover plate 10 is sealed, the waterproof membrane 25 for the basement roof is laid. After the waterproof membrane 25 is completed, a 25cm high L-shaped water retaining sill 5 is added on the longitudinal main structural beam 22 of the nearest structural column 7 on both sides of the post-pouring strip 15 along the direction of the post-pouring strip 15. Plastic pipes with a diameter of 5cm are pre-embedded in the L-shaped water retaining sill 5 every 10 meters or so to serve as drainage holes 12. The drainage holes 12 are sloped at 5% in the direction of drainage. Then, the waterproof protective layer 11 is poured.

[0035] Step 5: Referring to the position of the tie rod 13 with an outer diameter of 25mm pre-embedded in the structural slab 21 on both sides of the post-pouring strip, place two load-bearing I-beams 4 side by side on the L-shaped water retaining sills 5 on both sides of the post-pouring strip. The net distance between the two load-bearing I-beams 4 is 20cm, and the length of the load-bearing I-beams 4 is slightly shorter than the net distance of 2cm between the L-shaped water retaining sills 5.

[0036] Step 6: Place a 40cm long 20# bearing channel steel 3 directly above the pre-embedded tie rod 13. The groove of the bearing channel steel 3 is perpendicular to the load-bearing I-beam 4 with the groove facing downward. A 27mm diameter pre-reserved hole 26 is reserved on the web of the 20# bearing channel steel 3.

[0037] Step 7: Weld the top of a 50cm long lead screw with an outer diameter of 25mm to the middle of a 15cm long lead screw with an outer diameter of 25mm to form a T-shaped tie rod 2.

[0038] Step 8: Weld two 15cm×10cm×3cm iron blocks to both sides of one 10cm×10cm×3cm iron block to form a U-shaped component. Make a hole with a diameter of 27mm at a suitable position on each of the three sides of the U-shaped component to form a U-shaped hinge 8.

[0039] Step 9: Connect the U-shaped hinge 8, T-shaped tie rod 2, tie rod 13, bearing channel steel 3, and load-bearing I-beam 4 with nuts 1 to form a reliable pull-up support system.

[0040] Step 10: After the upper tensioning system is formed and the structural concrete reaches the appropriate strength, all bottom formwork supports can be removed.

[0041] Step 11: After the post-pouring strip 15 reaches the sealing requirement, install a 14mm outer diameter support screw 20 in the pre-embedded sleeve 19 at the bottom, install the main keel 18 square tube, and temporarily fix it with nuts 1. After installing the secondary keel 17 (timber) and the panel 16 template on the main keel 18, tighten the nuts 1 again to make the entire template system fit the structure.

[0042] Step 12: After the bottom formwork system is formed, concrete is poured through the upper reserved pouring hole. Finally, the concrete pouring surface is flush with the reserved steel pipe pouring port, and the pouring port is sealed and reinforced with a waterproof protective layer 11.

[0043] Example 3: A construction method for a bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs, such as... Figure 3 , Figure 4 , Figures 5 to 12 As shown, it includes the following steps: Step 1: When setting up the formwork for the post-pouring strip 15, a row of formwork support screws 18 with an outer diameter of 14mm is pre-embedded at a spacing of 60~80cm along the direction of the post-pouring strip 15 at the bottom of the formwork on both sides. The formwork support screws 18 are fixed by cross welding of additional reinforcement bars. The intersection of the additional reinforcement bars and the bottom structural steel bars 6 is also welded to form a reliable connection.

[0044] Step 2: Before pouring the concrete for the basement roof slab, embed a row of tie rods 13 with an outer diameter of 25mm at 15cm on both sides of the post-pouring strip 15, following the cyclical pattern of main beam, mid-span, main beam, mid-span, along the direction of the post-pouring strip 15.

[0045] Step 3: Chisel and clean the waterstop steel plates 14 and the concrete surfaces on both sides of the post-cast strip 15, and install 7cm thick precast cover plates 10. Concrete pouring holes are provided in the precast cover plates 10 every 3 meters. These holes are formed by pre-embedding a 25cm high, 15cm diameter steel pipe 9 with a waterstop flange 23 and a pipe thread 24 at the top of the pipe inside the precast cover plate 10 during casting. The pipe thread 24 can be used to tighten the cover plate.

[0046] Step 4: After the precast cover plate 10 is completed and sealed, the waterproof membrane 25 for the basement roof is laid. After the waterproof membrane 25 is completed, a 25cm high L-shaped water retaining sill 5 is added on the main structural beam 22 of the nearest structural column 7 on both sides of the post-pouring strip 15 along the direction of the post-pouring strip 15. Plastic pipes with a diameter of 5cm are pre-embedded in the L-shaped water retaining sill 5 every 10 meters or so to serve as drainage holes 12. The drainage holes 12 are sloped at 5% in the direction of drainage. Then, the waterproof protective layer 11 is poured.

[0047] Step 5: Referring to the positions of the 25mm diameter tie rods 13 pre-embedded in the structural slabs 21 on both sides of the post-pouring strip, place two load-bearing I-beams 4 side by side on the L-shaped water retaining sills 5 on both sides of the post-pouring strip. The net distance between the two load-bearing I-beams 4 is 20cm, and the length of the load-bearing I-beams 4 is slightly shorter than the net distance of 2cm between the L-shaped water retaining sills 5.

[0048] Step 6: Place a 40cm long 20# bearing channel steel 3 directly above the pre-embedded tie rod 13. The groove of the bearing channel steel 3 is perpendicular to the load-bearing I-beam 4 with the groove facing downward. A 27mm diameter reserved hole 26 is reserved on the web of the 20# bearing channel steel.

[0049] Step 7: Weld the top of a 50cm long lead screw with an outer diameter of 25mm to the middle of a 15cm long lead screw with an outer diameter of 25mm to form a T-shaped tie rod 2.

[0050] Step 8: Weld two 15cm×10cm×3cm iron blocks to both sides of one 10cm×10cm×3cm iron block to form a U-shaped component. Make a hole with a diameter of 27mm at a suitable position on each of the three sides of the U-shaped component to form a U-shaped hinge 8.

[0051] Step 9: Connect the U-shaped hinge 8, T-shaped tie rod 2, pre-reserved tie rod 13 on the top plate, bearing channel steel 3, and load-bearing I-beam 4 with nuts 1 to form a reliable pull-up support system.

[0052] Step 10: After the upper tensioning system is formed and the structural concrete reaches the appropriate strength, all bottom formwork supports can be removed.

[0053] Step 11: The support rib 33 is assembled by welding 1cm thick aluminum profiles. The connecting plate 29 at the bottom of the support rib 33 and the side ribs all have connecting holes 34. The reinforcing plate 30 is assembled by welding 1cm thick load-bearing plate 28 and 5cm wide and 1cm thick reinforcing ribs 27. The side ribs all have connecting holes 34. Among them, the load-bearing plate 28 and the reinforcing ribs 27 are both made of aluminum profiles.

[0054] Step 12: After the post-cast strip reaches the sealing requirement, insert the 14mm outer diameter support screws 18 on both sides of the bottom into the pre-drilled connection holes 34 at the bottom of the load-bearing plate 28 of the support rib 19, and fix them with nuts 1. Install the intermediate rib plate 30, and fix it to the support rib 33 through the pre-drilled connection holes 34 using pins 31 and wedges 32.

[0055] Step 13: After the bottom formwork system is formed, pour concrete through the upper reserved pouring hole. Finally, after the concrete pouring surface is flush with the reserved steel pipe pouring port, seal the pouring port and reinforce it with a waterproof protective layer 11.

[0056] This invention aims to solve the problems of long closure period of traditional post-pouring strips, the impact of bottom support on subsequent construction, and the harsh environment of basements. The structure includes setting up an upward-pull-type support system on the top slab to overcome the effects of structural settlement or temperature expansion and contraction; cleaning the post-pouring strip, hoisting a precast concrete cover plate to form a closed top surface, and finally carrying out subsequent construction under the protection of the cover plate; and using a support-free formwork system when pouring concrete for the post-pouring strip.

[0057] The above-described embodiments of the present invention, including a bottom-support-free structure and construction method for early sealing of post-pouring strips in basement roof slabs, do not constitute a limitation on the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A construction method for a bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs, characterized in that, Includes the following steps: Step 1: When setting up the formwork for the post-pouring strip, a row of connectors is pre-embedded at intervals along the direction of the post-pouring strip at the bottom of the formwork on both sides. The additional reinforcement is fixed to the connectors in a cross shape, and the additional reinforcement is connected to the main steel reinforcement of the bottom structure. Step 2: Before pouring the concrete for the basement roof slab, embed a row of tie rods 15cm on each side of the post-pouring strip according to the cyclical pattern of main beam, mid-span, main beam, mid-span along the direction of the post-pouring strip. Step 3: Chisel and clean the post-pouring strip, and install precast cover plates, with concrete pouring holes set at the precast cover plates every 3 meters. Step 4: After the precast cover plate is sealed, the waterproof membrane of the basement roof slab is laid. After the waterproof membrane of the roof slab is completed, an L-shaped water retaining sill is added on the main structural beams on both sides of the post-pouring strip along the direction of the post-pouring strip, and then the waterproof protective layer is poured. Step 5: Referring to the position of the tie rods pre-embedded in the structural slabs on both sides of the post-pouring strip, place two load-bearing I-beams side by side on the L-shaped water retaining sills on both sides of the post-pouring strip, with a net distance of 20cm between the two load-bearing I-beams. Step 6: Place a 40cm long bearing channel steel directly above the pre-embedded tie rod. The groove of the bearing channel steel is perpendicular to the load-bearing I-beam with the groove facing downwards. There are reserved holes on the web of the bearing channel steel. Step 7: Connect the U-shaped hinge, T-shaped tie rod, tie rod, load-bearing channel steel, and load-bearing I-beam with nuts to form an upward-pull-up support system; Step 8: After the upper tensioning system is formed and the structural concrete reaches the required strength, remove all bottom formwork supports; Step 9: After the post-pouring strip has met the sealing requirements, install the bottom formwork on the pre-embedded connectors at the bottom to ensure that the entire formwork system fits snugly with the structure. Step 10: After the bottom formwork system is formed, pour concrete through the upper reserved pouring hole. Finally, after the concrete pouring surface is flush with the reserved steel pipe pouring port, seal the pouring port and reinforce it with a waterproof protective layer.

2. The construction method for the bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs according to claim 1, characterized in that, In step 1, the spacing between the pre-embedded connectors is 60~80cm; the connectors are pre-embedded sleeves or support screws.

3. The construction method for the bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs according to claim 1, characterized in that, In step 3, the thickness of the precast cover plate is 7cm; the concrete pouring hole is formed by pre-embedding a 25cm high, 15cm diameter steel pipe with a water-stop flange and a pipe thread at the top of the pipe inside the precast cover plate during the casting process.

4. The construction method for the bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs according to claim 1, characterized in that, In step 4, the L-shaped water barrier is 25cm high, and a 5cm diameter plastic pipe is pre-embedded every 10 meters inside the L-shaped water barrier to serve as a drainage hole. The drainage hole is sloped at 5% towards the drainage direction.

5. The construction method for the bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs according to claim 1, characterized in that, In step 5, the length of the load-bearing I-beam is slightly shorter than the net distance of the L-shaped water retainer by 2cm; in step 7, the T-shaped tie rod is composed of a 50cm long lead rod with an outer diameter of 25mm at the top and a 15cm long lead rod with an outer diameter of 25mm at the middle.

6. The construction method for the bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs according to claim 1, characterized in that, In step 7, the U-shaped component is formed by fixing two 15cm×10cm×3cm iron blocks to both sides of a 10cm×10cm×3cm iron block, and holes are opened on three sides of the U-shaped component to form a U-shaped hinge.

7. The construction method for the bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs according to claim 2, characterized in that, When the pre-embedded connector is a pre-embedded sleeve, the bottom template includes a support screw and a main keel installed in the pre-embedded sleeve, and a secondary keel and a panel template installed on the main keel.

8. The construction method for the bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs according to claim 2, characterized in that, When the pre-embedded connector is a formwork support screw, the bottom template includes a support rib installed on the formwork support screw and an intermediate rib plate installed.

9. The construction method for the bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs according to claim 8, characterized in that, The supporting rib is assembled from 1cm thick aluminum profiles, and connection holes are provided at the bottom and side ribs of the supporting rib; the reinforcing plate is assembled from a 1cm thick load-bearing plate and 5cm wide and 1cm thick reinforcing ribs, and connection holes are provided on all four side ribs.

10. A bottom-support-free structure for early sealing of post-pouring strips in basement roof slabs, comprising formwork on both sides of the post-pouring strip, characterized in that, It also includes a row of tie rods pre-embedded in the basement roof slab along the direction of the post-pouring strip, a precast cover plate is set on the post-pouring strip, and a concrete pouring hole is set on the precast cover plate at the location every 3 meters; the basement roof slab and the precast cover plate are covered with roof slab waterproof membrane. L-shaped water-retaining sills are installed on the main beams on both sides of the post-cast strip along the direction of the post-cast strip. Two load-bearing I-beams are installed side by side on the L-shaped water-retaining sills at the location of the tie rod. A load-bearing channel steel is installed directly above the tie rod, with the groove of the load-bearing channel steel pointing downwards and perpendicular to the load-bearing I-beams. The U-shaped hinge, T-shaped tie rod, tie rod, load-bearing channel steel, and load-bearing I-beams are connected by nuts to form an upward-pull-up support system. A row of connectors is pre-embedded at 60-80cm intervals along the direction of the post-pouring strip at the bottom of the template, and the bottom template is installed on the connectors.

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