A method for formwork support and reinforcement construction of cast-in-place fair-faced concrete grandstand surface.

Abstract

A method for reinforcing the formwork support of cast-in-place fair-faced concrete for grandstand surfaces, characterized by the following steps: a) grandstand construction up to the steel mesh installation; b) vertical insertion of two rows of steel pipes (8) into the soil; c) intermittent reinforcement of the vertical formwork support for odd-numbered grandstand steps; d) intermittent pouring of fine aggregate concrete for odd-numbered grandstand steps; e) intermittent reinforcement of the vertical formwork support for even-numbered grandstand steps; f) reinforcement of the internal and external corners of the vertical support for even-numbered steps; g) intermittent pouring of fine aggregate concrete for even-numbered grandstand steps. This method for reinforcing the formwork support of cast-in-place fair-faced concrete for grandstand surfaces solves the construction difficulties in the prior art, such as the difficulty in reinforcing the formwork support when the grandstand surface is cast-in-place fair-faced concrete without damaging the waterproof layer or using tie bolts. It also strengthens the internal and external corner reinforcement of the vertical support for even-numbered steps and ensures the forming quality of the fair-faced concrete for the grandstand.

Description

Technical Field

[0001] This invention relates to a concrete formwork method, specifically a construction method for supporting and reinforcing formwork for cast-in-place fair-faced concrete on the surface of a grandstand. Background Technology

[0002] For public building projects like those in schools, the grandstand surface is typically cast-in-place fair-faced concrete, requiring high-quality molding. Without damaging the waterproofing layer, tie bolts cannot be used, and other external forces cannot be employed. Formwork support and reinforcement are difficult to implement, making it challenging to guarantee a smooth, fair-faced finish. Precast grandstand panels usually achieve good molding results, but significantly increase construction costs.

[0003] Therefore, the known construction method of cast-in-place fair-faced concrete for grandstand surfaces has the aforementioned inconveniences and problems. Summary of the Invention

[0004] The purpose of this invention is to provide a safe and reliable construction method for formwork support and reinforcement of cast-in-place fair-faced concrete grandstand surfaces.

[0005] To achieve the above objectives, the technical solution of the present invention is: A method for formwork support and reinforcement construction of cast-in-place fair-faced concrete for grandstand surfaces, in the case of soil around the grandstand, is characterized by the following steps: a. From the construction of the grandstand to the completion of the steel mesh construction, the width of the viewing steps on the finished grandstand structure is 750mm and the height of the viewing steps is 300mm. b. In the case of soil around the stands, two rows of steel pipes are vertically inserted into the soil as a reaction force template support reinforcement system. The parameters for the two rows of steel pipes are: horizontal spacing of 900mm and vertical spacing of 1200mm. The depth of the steel pipes inserted into the soil is at least 1 meter. The two rows of steel pipes are connected into a whole by longitudinal and transverse steel pipe fasteners. c. Interval reinforcement of the vertical formwork support for odd-numbered steps: The step formwork is made of 15mm thick plywood, and the horizontal secondary joists are made of 40mm*80mm square timber. 40mm*80mm square timber is laid flat along the direction of the steps at 1200mm intervals. The square timber is fixed to the reaction steel pipe and to the horizontal secondary joists of each odd-numbered step with nails. The square timber is continuously arranged along the direction of the steps, and short square timber of 40mm*80mm is added. The horizontal secondary joists of each adjacent odd-numbered step vertical support are fixed with nails at the front and back to form a whole, ensuring the support strength at the base of the vertical support of the steps. d. The odd-numbered grandstand steps are poured with fine aggregate concrete at intervals. The even-numbered grandstand steps that are not reinforced with formwork serve as the working surface for the workers, which facilitates the pouring and vibration. Intermittent pouring helps to control the finishing quality of the concrete steps of the grandstand. e. Interval reinforcement of the vertical formwork support for even-numbered steps: 15mm thick plywood is used for the step formwork, and 40mm*80mm square timber is used for the horizontal secondary joists. The timber is laid flat with vertical spacing. 40mm*80mm short square timber is laid flat with a spacing of 1200mm along the direction of the steps. The short square timber is fixed to the reaction steel pipe with nails. The short square timber can be arranged continuously along the direction of the steps. The horizontal secondary joist square timber of each adjacent even-numbered step vertical support is fixed with nails to form a whole, which facilitates force transmission. f. Reinforce the internal and external corners of the vertical supports for even-numbered steps. The internal corner of the support is located at the intersection of the side of the grandstand and the plane of the grandstand panel. Long steel pipes are arranged at 1200mm intervals along the direction of the grandstand steps. Add waist steel pipes perpendicular to the long steel pipes. The position of the waist steel pipes is flush with the plane of the already poured odd-numbered grandstand steps and connected to the long steel pipes with fasteners. Add short steel pipes at 1200mm intervals. One end is reinforced and tightened to the square timber at the internal corner of the vertical support of the steps, and the other end is connected to the waist steel pipes with fasteners. At the external corner where the long steel pipes intersect with the horizontal secondary keel square timber of the vertical support of even-numbered steps, add fasteners on the long steel pipes for reinforcement and tightening to prevent deformation during pouring. g. Pour fine aggregate concrete into the even-numbered grandstand steps at intervals. The odd-numbered grandstand steps that have been poured are used as the working surface for the workers, which facilitates pouring and vibration. Intermittent pouring helps to control the finishing quality of the concrete steps of the grandstand.

[0006] The formwork support and reinforcement construction method for cast-in-place fair-faced concrete grandstand surface layer of the present invention can also be further implemented by the following technical measures.

[0007] In the aforementioned method, the grandstand structure consists of, in sequence, a cement mortar leveling layer, a modified bitumen polyester waterproof membrane, an extruded polystyrene board, and a fine aggregate concrete protective layer, with a steel mesh embedded within the fine aggregate concrete protective layer.

[0008] In the aforementioned method, the concrete pouring proceeds from the lowest step upwards, with intermittent pouring aided by a tower crane, and the number of steps in each pour does not exceed five.

[0009] In the aforementioned method, the even-numbered step vertical support corners are reinforced with long I-beams before pouring.

[0010] The aforementioned method involves using an immersion vibrator to vibrate the concrete at the corners of the grandstand steps to ensure compaction. Manual finishing and troweling are then employed to guarantee the flatness of the grandstand concrete surface.

[0011] After adopting the above technical solution, the formwork support and reinforcement construction method for cast-in-place fair-faced concrete grandstand surface layer of the present invention has the following advantages: 1. Solve the construction difficulties in the existing technology, such as the difficulty of formwork support and reinforcement caused by the fact that the grandstand surface is cast-in-place fair-faced concrete without damaging the waterproof layer, without using tie bolts, and without relying on other external forces. 2. In the case of soil around the grandstand, two rows of steel pipes are vertically inserted into the soil as a reaction force formwork support and reinforcement system. The vertical formwork support of the odd-numbered and even-numbered grandstand steps is reinforced by intermittent reinforcement. The internal and external corners of the vertical support of the even-numbered steps are strengthened. The construction method of intermittently pouring fine stone concrete for the grandstand ensures that the concrete surface of the grandstand is of consistent color, the slab surface is flat, and the internal and external corners are full and straight. 3. While strictly controlling costs, the molding quality of the fair-faced concrete of the grandstand was guaranteed. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the cross-sectional structure of the grandstand building according to an embodiment of the present invention; Figure 2 This is a schematic plan view of the grandstand building according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the vertical support node of the grandstand steps according to an embodiment of the present invention; Figure 4 This is a cross-sectional view of the vertical support of the odd-numbered grandstand steps according to an embodiment of the present invention; Figure 5 This is a plan view of the vertical support of the odd-numbered grandstand steps according to an embodiment of the present invention; Figure 6 This is a cross-sectional view of the vertical support of the even-numbered steps of the grandstand according to an embodiment of the present invention; Figure 7 This is a plan view of the vertical support of the even-numbered steps of the grandstand according to an embodiment of the present invention; Figure 8 This is a cross-sectional view of the even-numbered step vertical support reinforcement at the inside and outside corners according to an embodiment of the present invention; Figure 9 This is a plan view of the vertical support reinforcement at the inside and outside corners of the even-numbered steps in an embodiment of the present invention.

[0013] In the diagram: 1-Stand structure; 2-20mm thick 1:2.5 cement mortar leveling; 3-4mm thick SBS + 3mm thick self-adhesive polymer modified bitumen polyester waterproof membrane; 4-50mm thick extruded polystyrene board; 5-80mm thick C20 fine stone concrete protective layer, reinforced with bidirectional 8@200 steel mesh; 6-Finished surface of the grandstand; 7-Soil around the grandstand; 8-Two rows of steel pipes; 9-15mm thick plywood; 10-Horizontal secondary joists, 40mm*80mm square timber (first); 11-40mm*80mm square timber (second); 12-40mm*80mm short square timber (first); 13-Even-numbered steps, 40mm*80mm short square timber (second); 14-Long steel pipe; 15-Waist steel pipe; 16-Short steel pipe; 17-Fasteners. Detailed Implementation

[0014] The present invention will be further described below with reference to the embodiments and accompanying drawings. Example

[0015] Please see now Figures 1-9 This invention discloses a method for formwork support and reinforcement construction of cast-in-place fair-faced concrete grandstand surfaces under soil conditions. In the case of soil around the grandstand, two rows of steel pipes are vertically inserted into the soil as a reaction-force formwork support and reinforcement system. The initial parameters for the two rows of steel pipes are a horizontal spacing of 900mm, a vertical spacing of 1200mm, and an insertion depth of at least 1 meter. The two rows of steel pipes are connected as a whole using longitudinal and transverse steel pipe couplers. The formwork support and reinforcement construction includes the following steps: 1. Construction of the grandstand, up to the completion of the steel mesh installation. Grandstand structure 1: Each step is 750mm wide and 300mm high. The construction method is as follows: 20mm thick 1:2.5 cement mortar leveling; 2. 4mm thick SBS + 3mm thick self-adhesive polymer-modified bitumen polyester waterproof membrane; 3. 50mm thick extruded polystyrene board; 4. 80mm thick C20 fine aggregate concrete protective layer, reinforced with bidirectional 8@200 steel mesh; 5. Finished grandstand surface 6: Each step is 750mm wide and 300mm high.

[0016] 2. In the case of soil around the grandstand (condition 7), two rows of steel pipes (8) are vertically inserted into the soil as a reaction force formwork support and reinforcement system. The area around the grandstand in school and public building projects is usually a school playground, with soil on the ground surface, mostly backfill. The initial parameters for the two rows of steel pipes are: a horizontal spacing of 900mm, a vertical spacing of 1200mm, and an insertion depth of at least 1 meter into the soil. The two rows of steel pipes are connected as a whole using longitudinal and transverse steel pipe couplers to bear the load.

[0017] 3. Reinforcement of the vertical formwork support for odd-numbered grandstand steps. The step formwork uses 15mm thick plywood (9), and the horizontal secondary joists use 40mm*80mm square timber (10), laid flat with vertical spacing. Along the grandstand steps, 40mm*80mm square timber (11) is laid flat at 1200mm intervals. The timber is fixed to the reaction steel pipes and to the horizontal secondary joists of each odd-numbered step using nails. The timber can be continuously arranged along the grandstand steps. Add short 40mm*80mm square timber (12). The horizontal secondary joists of each adjacent odd-numbered step's vertical support are fixed with nails from front to back, forming a unified structure to ensure the strength of the vertical support base.

[0018] 4. Pour fine aggregate concrete for odd-numbered grandstand steps at intervals. During pouring, the even-numbered grandstand steps that are not reinforced with formwork can serve as the working surface for workers, facilitating pouring and vibration. Intermittent pouring helps control the finishing quality of the grandstand concrete steps.

[0019] 5. Reinforcement of vertical formwork supports for even-numbered grandstand steps. The step formwork uses 15mm thick plywood, and the horizontal secondary joists are made of 40mm*80mm square timber, laid flat with vertical spacing. Along the grandstand steps, 40mm*80mm short square timbers are laid flat at 1200mm intervals, fixed to the reaction steel pipes with nails. The short square timbers can be continuously arranged along the grandstand steps. The horizontal secondary joists of the vertical supports for adjacent even-numbered steps are fixed with nails to form a unified structure for easy force transmission.

[0020] 6. Reinforcement of the internal and external corners of the vertical supports for even-numbered steps. The internal corner is located at the junction of the side of the grandstand and the plane of the grandstand slab. To ensure the quality of the concrete forming at the internal corner, long steel pipes 14 are arranged at 1200mm intervals along the direction of the grandstand steps. A horizontal steel pipe 15 is added perpendicular to the long steel pipes, with its position flush with the already poured plane of the odd-numbered grandstand steps and connected to the long steel pipes with fasteners. Short steel pipes 16 are added at 1200mm intervals, one end reinforced and tightened to the square timber at the internal corner of the vertical support for the step, and the other end connected to the horizontal steel pipe with fasteners. At the external corner where the long steel pipe intersects with the horizontal secondary joist square timber of the even-numbered step vertical support, fasteners 17 are added to the long steel pipe for reinforcement and tightening to prevent deformation during pouring.

[0021] 7. Pour fine aggregate concrete for even-numbered grandstand steps at intervals. During pouring, the already poured odd-numbered grandstand steps can serve as the working surface for workers, facilitating pouring and vibration. Intermittent pouring helps control the finishing quality of the grandstand concrete steps.

[0022] In the specific operation of the formwork support reinforcement construction method for the cast-in-place fair-faced concrete surface of the grandstand according to the present invention, the grandstand concrete is poured from the lowest step upwards using a tower crane at intervals, and it is recommended that the number of steps poured each time not exceed five. For the external corners of the vertical supports of even-numbered steps, long I-beams or other counterweight measures can be added before pouring.

[0023] An immersion vibrator was used to compact the concrete, with a focus on the corners of the grandstand steps, to ensure the concrete was dense. Manual finishing and troweling were then used to ensure the concrete surface was smooth.

[0024] Strictly control the concrete formwork removal time. The removal time should ensure that the wall will not chip or peel after the formwork is removed. It is recommended to remove the side formwork of the stair steps after 48 hours.

[0025] The thickness of the grandstand construction is 150mm. The grandstand structure and the finished surface of the grandstand are 750mm wide and 300mm high per step. It can be understood that the grandstand structure is moved forward by 150mm to form the finished surface of the grandstand.

[0026] To avoid and reduce color differences on the surface of fair-faced concrete, water should be sprayed multiple times within 12 hours after the concrete is poured for curing.

[0027] This invention possesses substantial features and significant technological advancements. The formwork support and reinforcement construction method for cast-in-place fair-faced concrete grandstand surfaces, as described in this invention, solves the construction difficulties in existing technologies where the grandstand surface is cast-in-place fair-faced concrete. This method avoids damaging the waterproof layer, using tie bolts, and cannot utilize other external forces, leading to difficulties in formwork support and reinforcement. The advantages of this method are as follows: In situations where there is soil around the grandstand, two rows of steel pipes are vertically inserted into the soil as a reaction force formwork support and reinforcement system. Through intermittent reinforcement of the vertical formwork support for odd-numbered and even-numbered grandstand steps, and strengthening the internal and external corner reinforcement of the even-numbered steps, the method employs intermittent pouring of fine aggregate concrete for the grandstand, ensuring a consistent concrete color, a flat surface, and full, straight internal and external corners. This method guarantees the quality of the fair-faced concrete formation while strictly controlling costs.

[0028] The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention. Therefore, all equivalent technical solutions should also fall within the scope of this invention and are defined by the claims.

Claims

1. A method for formwork support and reinforcement construction of cast-in-place fair-faced concrete for grandstand surfaces, characterized in that: The method takes the grandstand structure with completed steel mesh construction as a benchmark, sets up a steel pipe support system in the ground soil to form a reaction force according to the design dimensions of the grandstand steps, and combines the alternating formwork support and intermittent pouring process of odd and even steps to achieve the overall stability of the formwork support and control of the concrete forming quality. Includes the following steps: a. The construction of the grandstand is completed from the construction of the steel mesh. The width of the viewing steps on the finished surface (6) of the grandstand structure (1) is 750mm and the height of the viewing steps is 300mm. b. When there is soil around the stands (7), two rows of steel pipes (8) are vertically inserted into the soil as a template support reinforcement system for the reaction force. The parameters of the two rows of steel pipes are: horizontal spacing of 900mm and vertical spacing of 1200mm. The depth of the steel pipes inserted into the soil is at least 1 meter. The two rows of steel pipes are connected into a whole by longitudinal and transverse steel pipe fasteners. c. Interval reinforcement of the vertical formwork support of the odd-numbered steps: 15mm thick plywood (9) is used for the step formwork, and 40mm*80mm square timber (10) is used for the horizontal secondary keel. 40mm*80mm square timber (11) is laid flat along the direction of the steps at a spacing of 1200mm. The square timber (11) is fixed with the reaction steel pipe and the square timber (11) is fixed with the horizontal secondary keel square timber (10) of each odd-numbered step by nails. The square timber (11) is continuously arranged along the direction of the steps. 40mm*80mm short square timber (12) is added. The horizontal secondary keel square timber (10) of each adjacent odd-numbered step vertical support is fixed with nails in front and behind to form a whole and ensure the support strength of the vertical support root of the steps. d. The odd-numbered grandstand steps are poured with fine aggregate concrete at intervals. The even-numbered grandstand steps that are not reinforced with formwork serve as the working surface for the workers, which facilitates the pouring and vibration. Intermittent pouring helps to control the finishing quality of the concrete steps of the grandstand. e. Interval reinforcement of the vertical formwork support of even-numbered steps of the viewing stairs. The formwork of the steps is made of 15mm thick plywood, and the horizontal secondary keel is made of 40mm*80mm square timber. The upper and lower spacing is flat. Along the direction of the viewing stairs, 40mm*80mm short square timbers are laid flat at a spacing of 1200mm (13). The short square timbers are fixed to the reaction steel pipes with nails. The short square timbers are continuously arranged in the direction of the viewing stairs. The horizontal secondary keel square timbers of each adjacent even-numbered step vertical support are fixed with nails to form a whole, which is convenient for force transmission. f. Reinforce the internal and external corners of the vertical support for even-numbered steps. The internal corner of the support is located at the intersection of the side of the grandstand and the plane of the grandstand board. Long steel pipes (14) are arranged at 1200mm intervals along the direction of the grandstand steps. Waist steel pipes (15) are added in the direction perpendicular to the long steel pipes. The position of the waist steel pipes is level with the plane of the already poured odd-numbered steps of the grandstand and is connected to the long steel pipes with fasteners. Short steel pipes (16) are added at 1200mm intervals. One end is reinforced and tightened with the square timber at the internal corner of the vertical support of the steps, and the other end is connected to the waist steel pipes with fasteners. At the external corner where the long steel pipes intersect with the horizontal secondary keel square timber of the vertical support of even-numbered steps, fasteners (17) are added to the long steel pipes to reinforce and tighten them to avoid deformation during pouring. g. Pour fine aggregate concrete into the even-numbered grandstand steps at intervals. The odd-numbered grandstand steps that have been poured are used as the working surface for the workers, which facilitates pouring and vibration. Intermittent pouring helps to control the finishing quality of the concrete steps of the grandstand.

2. The method for formwork support and reinforcement construction of cast-in-place fair-faced concrete for grandstand surface as described in claim 1, characterized in that, The grandstand structure (1) consists of, in sequence, a cement mortar leveling layer (2), a modified asphalt polyester waterproof membrane (3), an extruded polystyrene board (4), and a fine stone concrete protective layer, with a steel mesh (5) inside the fine stone concrete protective layer.

3. The method for formwork support and reinforcement construction of cast-in-place fair-faced concrete for grandstand surface as described in claim 1, characterized in that, The concrete pouring begins from the lowest step and proceeds upwards, with intermittent pouring using a tower crane. Each pouring session involves no more than five steps.

4. The method for formwork support and reinforcement construction of cast-in-place fair-faced concrete for grandstand surface as described in claim 1, characterized in that, For the even-numbered stepped vertical support at the external corner, long I-beams are added for weight-bearing before pouring.

5. The method for formwork support and reinforcement construction of cast-in-place fair-faced concrete for the grandstand surface layer as described in any one of claims 1-4, characterized in that, The pouring and vibration are carried out using an immersion vibrator to vibrate the inside corners of the grandstand steps, making the concrete dense. The surface is then manually smoothed and pressed to ensure the flatness of the concrete surface.

6. The method for formwork support and reinforcement construction of cast-in-place fair-faced concrete for grandstand surface as described in claim 1, characterized in that: The process of alternating odd-numbered and even-numbered formwork and intermittent pouring is configured to use the unpoured steps as a working platform during each pouring process to facilitate pouring and vibration, thereby achieving controllable quality of the step surface.

7. The method for formwork support and reinforcement construction of cast-in-place fair-faced concrete for grandstand surface as described in claim 1, characterized in that: At the internal and external corners of the even-numbered step vertical support, a composite constraint unit is set up, consisting of a long steel pipe along the step, a waist steel pipe perpendicular to it, and a short steel pipe that is tightly pressed against the square timber at the internal corner. This composite constraint unit is used to limit the displacement of the nodes during the pouring process and to prevent the template at the external corner from bulging or deforming, so as to ensure the forming quality of the internal and external corners.

8. The method for formwork support and reinforcement construction of cast-in-place fair-faced concrete for grandstand surface as described in claim 1, characterized in that: The timing of formwork removal should be controlled to ensure that the concrete of the grandstand does not chip or peel after formwork removal; in particular, the removal time of the side formwork of the steps should not be earlier than 48 hours to ensure the molding quality and appearance.

9. The method for formwork support and reinforcement construction of cast-in-place fair-faced concrete for grandstand surface as described in claim 1, characterized in that: Multiple water sprayings are carried out within 12 hours after the concrete is poured to reduce color difference on the surface of fair-faced concrete and improve surface smoothness and consistency.

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