A support-free construction method for cast-in-situ face plate of laminated slab

Abstract

This application discloses a method for constructing cast-in-place composite slab panels without supports, relating to the technical field of cast-in-place composite slab construction. The method includes the following steps: Step 1, load-bearing beam construction: fixing multiple load-bearing beams at the bottom of the composite slab installation location; Step 2, formwork installation: erecting and fixing the formwork frame to the top of the load-bearing beams; Step 3, composite slab laying: hoisting and laying each composite slab onto the formwork frame; Step 4, rebar tying: tying and fixing the pre-embedded rebars on adjacent composite slabs; Step 5, formwork construction: erecting a formwork on the composite slab; Step 6, concrete pouring: pouring the mixed concrete into the formwork; Step 7, formwork removal: removing the formwork after the concrete has solidified. This application has the advantages of reducing the likelihood of formwork bulging and misalignment during cast-in-place composite slab construction, and ensuring good overall integrity and reducing the likelihood of cracks after the cast-in-place composite slab panels are completed.

Description

Technical Field

[0001] This application relates to the technical field of cast-in-place construction of composite slabs, and in particular to a method for constructing cast-in-place panels of composite slabs without supports. Background Technology

[0002] With the advancement of technology and the development of the construction industry, prefabricated buildings are being vigorously promoted. Composite floor slabs, as the main components in prefabricated buildings, have advantages such as good structural integrity, high rigidity, no increase in steel consumption, and saving on formwork. Moreover, composite slabs are suitable for industrialized production, and their pollution and waste are much lower than those of on-site production, which meets the requirements of green construction and green building.

[0003] The existing construction process for cast-in-place composite slab panels mainly includes surveying and setting out, erecting a scaffolding system, laying timber joists, hoisting the composite slabs, tying reinforcing bars, and pouring concrete. During construction, the scaffolding serves as the overall load-bearing structure for the cast-in-place composite slab. However, this method has certain limitations. The overall stress of the composite slab must be considered during construction, specifically whether bulging or misalignment will occur during concrete pouring. After the cast-in-place composite slab panel is completed, the scaffolding must be completely removed. After removal, the overall stress of the cast-in-place composite slab panel changes, making it prone to cracking after a period of use. Therefore, the existing construction process for cast-in-place composite slab panels has significant room for improvement. Summary of the Invention

[0004] To address the problems existing in the prior art, this application provides a method for constructing cast-in-place composite slab panels without supports. This method reduces the likelihood of formwork bulging and misalignment during the cast-in-place construction of composite slabs, and ensures good integrity and reduces the likelihood of cracks after the cast-in-place composite slab panels are completed.

[0005] A method for constructing cast-in-place panels of composite slabs without supports includes the following steps:

[0006] Step 1: Construction of load-bearing beams. Hoist multiple load-bearing beams to the bottom of the composite slab installation position, and level the formwork support. Fix both ends of the load-bearing beams to the load-bearing columns on both sides respectively.

[0007] Step 2: Install the formwork support. Place the formwork support on top of the load-bearing beam, and then weld and fix the formwork support to the load-bearing beam.

[0008] Step 3: Laying composite slabs. Hoist each composite slab onto the formwork support and adjust the position of each composite slab.

[0009] Step 4: Reinforcement binding. Bind and fix the pre-embedded reinforcement on the two adjacent composite slabs, and bind the composite slab to the formwork frame through the pre-embedded reinforcement on the composite slab. Then lay prestressed reinforcement on top of each composite slab, and bind the prestressed reinforcement to the pre-embedded reinforcement on the composite slab.

[0010] Step 5: Construction of casting formwork. Set up casting formwork on the composite slab and install steel cages on the inner wall of the casting formwork. Tie the steel cages to the prestressed steel bars and fix them in place.

[0011] Step 6: Concrete pouring. Pour the mixed concrete into the casting form and cure the concrete.

[0012] Step 7: Remove the formwork. After the concrete has hardened, remove the casting formwork.

[0013] By adopting the above technical solution, the load-bearing beams support the formwork and composite slabs without the need for additional supports, effectively improving construction efficiency. Furthermore, the load-bearing beams are directly fixed to the load-bearing columns on both sides, ensuring a stable installation structure and more robust support for the composite slabs. This reduces the likelihood of formwork bulging or misalignment during subsequent concrete pouring. Moreover, since the load-bearing beams do not need to be removed after the composite slab is cast in place, the stress during the casting process remains consistent with the stress during subsequent use, resulting in better overall integrity and reducing the likelihood of cracks during use.

[0014] Optionally, when laying the composite slabs, a pouring joint is reserved between two adjacent composite slabs. The width of the pouring joint is set at 5-10cm. When pouring concrete, the pouring joint between the two composite slabs is filled with concrete.

[0015] By adopting the above technical solution, the setting of the pouring joint facilitates the binding of the pre-embedded steel bars, and during the subsequent concrete pouring process, the pouring joint between two adjacent composite slabs is filled with concrete, making the connection between the two adjacent composite slabs more solid, thereby increasing the overall structural stability of the cast-in-place composite slab panel.

[0016] Optionally, before pouring concrete, a bottom formwork is installed at the bottom of the formwork frame and between two adjacent load-bearing beams. After the concrete is poured, the formwork frame is embedded in the concrete. After the concrete has completely solidified, the bottom formwork is removed.

[0017] Optionally, a pouring port is provided on the bottom formwork, and concrete is poured from the bottom up through the pouring port on the bottom formwork during pouring.

[0018] By adopting the above technical solution, the concrete is poured from the bottom up during the pouring process, which effectively avoids the formation of air bubbles inside the cast-in-place composite slab panel after the construction of the composite slab panel, thus affecting the structural strength of the cast-in-place composite slab panel.

[0019] Optionally, after the concrete is poured, the bottom of the formwork is tapped with a wooden hammer to compact the concrete.

[0020] Optionally, during installation, the joint between the bottom formwork and the load-bearing beam should be filled with sealing sponge.

[0021] By employing the above technical solution, the gap between the bottom formwork and the load-bearing beam is sealed with sealing sponge, thus preventing grout leakage during concrete pouring.

[0022] Optionally, the load-bearing beam is made of I-beams, and several reinforcing ribs are fixedly installed on the I-beams.

[0023] Optionally, after the load-bearing beam is installed, prestressed tendons are connected to both ends of the load-bearing beam, and clamps are fixed to the load-bearing columns on both sides of the load-bearing beam with tie bolts. The clamps are installed above the load-bearing beam, and the prestressed tendons are hinged to the clamps. After the concrete is poured, the prestressed tendons are embedded in the concrete.

[0024] Optionally, during installation, a slot is first cut into the load-bearing column at a downward angle, the load-bearing rod is inserted into the slot, and then the load-bearing rod is welded and fixed to the clamp.

[0025] By adopting the above technical solution, a portion of the load of the load-bearing beam is transferred to the clamps through the prestressed tendons, and then transferred to the interior of the load-bearing column through the load-bearing bars, thereby further increasing the structural stability of the load-bearing beam on the load-bearing column.

[0026] In summary, this application includes at least one of the following beneficial technical effects:

[0027] 1. By setting up load-bearing beams, the formwork and composite slabs are supported without the need for additional supports, effectively improving construction efficiency. The load-bearing beams are directly fixed to the load-bearing columns on both sides, ensuring a stable installation structure and providing more robust support for the composite slabs. This reduces the likelihood of formwork bulging or misalignment during subsequent concrete pouring. Furthermore, since the load-bearing beams do not need to be removed after the composite slab is cast in place, the internal stress of the cast-in-place panel during casting is essentially consistent with its stress during subsequent use. This results in better overall integrity of the cast-in-place panel and reduces the likelihood of cracks during use.

[0028] 2. During the concrete pouring process, pour from the bottom up to effectively avoid air bubbles appearing inside the composite slab cast-in-place panel after the construction is completed, which would affect the structural strength of the composite slab cast-in-place panel.

[0029] 3. Part of the load of the load-bearing beam is transferred to the clamps through the prestressed tendons, and then to the interior of the load-bearing column through the load-bearing bars, thereby further increasing the structural stability of the load-bearing beam on the load-bearing column. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application;

[0031] Figure 2 This is a partial structural schematic diagram of an embodiment of this application, mainly used to illustrate the installation structure of the load-bearing beam;

[0032] Figure 3 yes Figure 2 Enlarged view of section A;

[0033] Figure 4 This is a schematic diagram illustrating the structure of the formwork support frame according to an embodiment of this application;

[0034] Figure 5 This is a schematic diagram illustrating the structure of the composite plate according to an embodiment of this application;

[0035] Figure 6 yes Figure 5 Enlarged view of section B;

[0036] Figure 7 This is a schematic diagram illustrating the structure of the base template in an embodiment of this application;

[0037] Figure 8 yes Figure 7 A magnified view of section C.

[0038] Explanation of reference numerals in the attached drawings: 1. Load-bearing beam; 11. Reinforcing rib; 12. Prestressed tendon; 13. First connecting frame; 14. Angle steel; 2. Load-bearing column; 21. Supporting steel frame; 211. Placement groove; 22. Clamp; 221. Second connecting frame; 23. Load-bearing rod; 231. Top slab; 232. Rib plate; 3. Formwork support frame; 4. Composite slab; 41. Pouring joint; 5. Prestressed steel reinforcement; 6. Pouring formwork; 7. Reinforcing cage; 8. Bottom formwork; 81. Sealing sponge; 82. Pouring port. Detailed Implementation

[0039] The following is in conjunction with the appendix Figure 1-8 This application will be described in further detail.

[0040] This application discloses a method for constructing cast-in-place panels of composite slabs without supporting supports. (Refer to...) Figure 1 This includes the following steps:

[0041] Step 1: Construction of load-bearing beam 1;

[0042] Reference Figure 1 , 2 Mark and mark the installation positions of each load-bearing beam 1 at the construction location. Fix the supporting steel frame 21 to the load-bearing columns 2 on both sides of the installation position of the load-bearing beam 1 with expansion bolts. The supporting steel frame 21 has a placement groove 211 that matches the load-bearing beam 1. When installing the supporting steel frame 21, it is necessary to ensure that the load-bearing beam 1 is in a horizontal state after the subsequent installation and that the top walls of each load-bearing beam 1 are on the same horizontal plane. Then, hoist each load-bearing beam to its respective installation position and place both sides of the load-bearing beam 1 into the placement groove 211 on the two sides of the supporting steel frame 21. Finally, weld and fix the load-bearing beam 1 to the supporting steel frame 21.

[0043] Reference Figure 2 The load-bearing beam 1 is made of I-beams, and several reinforcing ribs 11 are fixedly installed on the I-beams to ensure the structural strength of the load-bearing beam 1 itself and to prevent deformation due to excessive load during use.

[0044] Reference Figure 2 , 3 After the load-bearing beam 1 is installed, clamps 22 are fixed on the load-bearing columns 2 on both sides of the load-bearing beam 1. The clamps 22 are installed above the load-bearing beam 1. The clamps 22 are made of steel and include two C-shaped frames that are adapted to the load-bearing columns 2. The two C-shaped frames are fitted onto the load-bearing columns 2 and clamped and fixed to the load-bearing columns 2 by tie bolts. When installing the clamps 22, a slot is made on the load-bearing column 2 below the installation position of the clamps 22 in a downward diagonal direction. The load-bearing rod 23 is inserted into the slot. The load-bearing rod 23 is made of steel. Then, the load-bearing rod 23 is welded and fixed to the clamps 22.

[0045] Reference Figure 3After the clamp 22 is fixed, prestressed tendons 12 are connected to both ends of the load-bearing beam 1 and the prestressed tendons 12 are hinged to the clamp 22. Through holes are opened on both ends of the prestressed tendons 12 along the length direction perpendicular to the prestressed tendons 12. A first connecting frame 13 is fixedly installed at both ends of the load-bearing beam 1. A first through hole is opened on the first connecting frame 13, and a first bolt is inserted into the first through hole. A first nut is fitted on the first bolt. When connecting the prestressed tendons 12 to the load-bearing beam 1, the through hole on one side of the prestressed tendon 12 is aligned with the first through hole on the first connecting frame 13. Then, the first bolt is passed through the first through hole on the first connecting frame 13 and the through hole on the prestressed tendon 12 at the same time, and the first nut is threaded onto the first bolt. The prestressed tendons 12 can then be installed on the load-bearing beam 1.

[0046] Reference Figure 3 The bottom of one of the C-shaped frames of the clamp 22 is fixedly provided with a second connecting frame 221, and a second through hole is opened on the second connecting frame 221. A second bolt is inserted into the second through hole, and a first nut is fitted on the second bolt. When the clamp 22 connects the prestressed tendon 12, the through hole on the side of the prestressed tendon 12 away from the load-bearing beam 1 is aligned with the second through hole on the second connecting frame 221. Then, the second bolt is passed through the second through hole of the second connecting frame 221 and the through hole on the prestressed tendon 12, and the second nut is threaded onto the second bolt, thereby hinged the prestressed tendon 12 to the clamp 22. After the prestressed tendon 12 is installed, it is necessary to ensure that the length direction of the prestressed tendon 12 is vertical.

[0047] Reference Figure 3 Furthermore, a top plate 231 is welded to the side wall of the load-bearing rod 23. After the load-bearing rod 23 is inserted into the insertion slot on the load-bearing column 2, the top plate 231 abuts against and fits against the side wall of the load-bearing column 2. Multiple ribs 232 are fixedly provided on the side wall of the load-bearing rod 23 along the circumference of the load-bearing rod 23, and the ribs 232 are fixedly connected to the top plate 231.

[0048] Step 2: Install the formwork support 3;

[0049] Reference Figure 4 After the load-bearing beam 1 is installed, a formwork support frame 3 is erected on the top of each load-bearing beam 1. The formwork support frame 3 is welded together from several square steel pipes. During construction, the formwork support frame 3 is first assembled and welded on the ground, and then hoisted onto the load-bearing beam 1. During installation, the formwork support frame 3 needs to be leveled. After the formwork support frame 3 is erected, it is then welded and fixed to the load-bearing beam 1.

[0050] Step 3: Lay the composite slab 4;

[0051] Reference Figure 5 , 6Multiple composite slabs 4 are hoisted sequentially onto the formwork support 3, and their positions are adjusted before being slowly placed on the formwork support 3. During the laying of the composite slabs 4, a pouring joint 41 is reserved between adjacent composite slabs 4. The width of the pouring joint 41 is controlled between 5-10cm to ensure that the width of the pouring joint 41 between each composite slab 4 is consistent. The setting of the pouring joint 41 facilitates the binding of the embedded steel bars, and during the subsequent concrete pouring process, the pouring joint 41 between adjacent composite slabs 4 is filled with concrete, making the connection between adjacent composite slabs 4 more solid, thereby increasing the overall structural stability of the cast-in-place composite slab panel.

[0052] Step 4: Rebar tying;

[0053] Reference Figure 5 , 6 The composite slab 4 is embedded with several pre-embedded steel bars, which extend out of the side of the composite slab 4. After each composite slab 4 is laid, the pre-embedded steel bars on the adjacent composite slab 4 are tied and fixed, and the pre-embedded steel bars on the composite slab 4 are tied and fixed to the formwork frame 3. Then, prestressed steel bars 5 are laid on top of each composite slab 4, and the prestressed steel bars 5 are tied and fixed to the pre-embedded steel bars on the composite slab 4.

[0054] Step 5: Pouring the formwork; Step 6: Construction.

[0055] Reference Figure 5 , 7 A casting formwork 6 is erected on top of the composite slab 4. Then, the tied steel cage 7 is placed inside the casting formwork 6, and the steel bars are tied and fixed to the prestressed steel bars 5.

[0056] Reference Figure 7 , 8 After the formwork 6 is poured, the bottom formwork 8 is installed at the bottom of the formwork support 3 and between the two adjacent load-bearing beams 1. A release agent is applied to the top wall of the bottom formwork 8. When installing the bottom formwork 8, the angle steel 14 is fixed to the load-bearing beam 1 and below the bottom formwork 8 with bolts. The angle steel 14 abuts against the bottom wall of the bottom formwork 8, and then the angle steel 14 is fixed to the bottom formwork 8 with screws, thereby supporting the bottom formwork 8.

[0057] Reference Figure 8 When installing the bottom formwork 8, sealant sponge 81 is filled at the joint between the bottom formwork 8 and the load-bearing beam 1; the sealant sponge 81 seals the gap between the bottom formwork 8 and the load-bearing beam 1 to prevent grout leakage during concrete pouring.

[0058] Step 6: Concrete pouring;

[0059] Reference Figure 7A pouring port 82 is provided on the bottom formwork 8. During concrete pouring, the mixed concrete is poured from the bottom up through the pouring port 82. The concrete successively submerges the formwork 3, the composite slab 4, and the reinforcing cage 7. After the concrete is poured, the pouring port 82 is sealed, and the bottom of the bottom formwork 8 is tapped with a wooden hammer to compact the concrete. The top of the concrete inside the pouring formwork 6 is then smoothed. After the concrete is poured, the formwork 3, composite slab 4, prestressed steel bars 5, prestressed tendons 12, clamps 22, and reinforcing cage 7 are all embedded in the concrete, and the pouring joint 41 between two adjacent composite slabs 4 is filled with concrete. The concrete is poured from the bottom up during the pouring process to effectively prevent air bubbles from appearing inside the composite slab 4 after the cast-in-place panel is constructed, which would affect the structural strength of the composite slab 4.

[0060] Step 7: Demolding;

[0061] After the concrete has solidified and met the conditions for demolding, the casting formwork 6 and bottom formwork 8 are completely removed; the construction of the cast-in-place panel of the composite slab 4 is completed.

[0062] The implementation principle of the method for constructing a cast-in-place composite slab panel without a support frame in this application embodiment is as follows: The load-bearing beam 1 supports the formwork scaffold 3 and the composite slab 4, eliminating the need for additional supports. The load-bearing beam 1 is directly fixed to the load-bearing columns 2 on both sides, ensuring a stable installation structure and thus providing more robust support for the composite slab 4. This reduces the likelihood of formwork bulging or misalignment during subsequent concrete pouring. Furthermore, since the load-bearing beam 1 does not need to be removed after the cast-in-place construction of the composite slab 4 is completed, the internal stress of the cast-in-place panel during the casting process remains essentially consistent with the stress during subsequent use. This results in better overall integrity of the cast-in-place panel and reduces the likelihood of cracks during subsequent use. Moreover, eliminating the need for supports saves time on support erection and dismantling, effectively improving construction efficiency and shortening the construction cycle.

[0063] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for constructing cast-in-place panels of composite slabs without supports, characterized in that, Includes the following steps: Step 1: Construction of load-bearing beams (1): Hoist multiple load-bearing beams (1) to the bottom of the composite slab (4) installation position, and level the formwork frame (3). The two ends of the load-bearing beams (1) are fixed to the load-bearing columns (2) on both sides respectively. Step 2: Install the formwork support (3). Place the formwork support (3) on top of the load-bearing beam (1), and then weld and fix the formwork support (3) to the load-bearing beam (1). Step 3: Laying of composite slabs (4): Hoist each composite slab (4) and lay it on the formwork support (3), and adjust the position of each composite slab (4); Step 4: Reinforcing bar binding. The pre-embedded reinforcing bars on the two adjacent composite slabs (4) are bound and fixed. The composite slabs (4) are bound and fixed to the formwork frame (3) through the pre-embedded reinforcing bars on the composite slabs (4). Then, prestressed reinforcing bars (5) are laid on top of each composite slab (4), and the prestressed reinforcing bars (5) are bound and fixed to the pre-embedded reinforcing bars on the composite slabs (4). Step 5: Construction of the casting formwork (6). The casting formwork (6) is erected on the composite slab (4), and a steel cage (7) is set on the inner wall of the casting formwork (6). The steel cage (7) is tied and fixed to the prestressed steel bars (5). Step 6: Concrete pouring. Pour the mixed concrete into the pouring formwork (6) and cure the concrete. Step 7: Remove the formwork. After the concrete has solidified, remove the casting formwork (6). When the composite slab (4) is laid, a pouring joint (41) is reserved between two adjacent composite slabs (4). The width of the pouring joint (41) is set at 5-10cm. When the concrete is poured, the pouring joint (41) between the two composite slabs (4) is filled with concrete. Before the concrete is poured, the bottom formwork (8) is installed at the bottom of the formwork frame (3) and between the two adjacent load-bearing beams (1). After the concrete is poured, the formwork frame (3) is embedded in the concrete. After the concrete is completely solidified, the bottom formwork (8) is removed. A pouring port (82) is provided on the bottom formwork (8). When the concrete is poured, it is poured from the bottom to the top through the pouring port (82) on the bottom formwork (8). After the load-bearing beam (1) is installed, prestressed tendons (12) are connected to both ends of the load-bearing beam (1). Clamps (22) are fixed on the load-bearing columns (2) on both sides of the load-bearing beam (1) by tie bolts. The clamps (22) are installed above the load-bearing beam (1). The prestressed tendons (12) are hinged to the clamps (22). After the concrete is poured, the prestressed tendons (12) are embedded in the concrete.

2. The method according to claim 1, wherein the method is characterized in that: After the concrete is poured, the bottom of the bottom formwork (8) is tapped with a wooden hammer to compact the concrete.

3. The method according to claim 1, wherein the method is characterized in that: When installing the bottom formwork (8), sealant sponge (81) is filled at the joint between the bottom formwork (8) and the load-bearing beam (1).

4. The method for constructing cast-in-place composite slab panels without supports according to claim 1, characterized in that: The load-bearing beam (1) is made of I-beams, and several reinforcing ribs (11) are fixedly installed on the I-beams.

5. The method according to claim 1, wherein the method is characterized in that: When installing the clamp (22), first open the insertion groove on the load-bearing column (2) in the downward direction, insert the load-bearing rod (23) into the insertion groove, and then weld the load-bearing rod (23) to the clamp (22) for fixation.

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