Prefabricated large cantilever heat insulation floor and construction method thereof

Abstract

The application relates to an assembled large cantilever heat insulation floor and a construction method thereof, effectively solving the problems of poor bearing capacity of the cantilever structure and exposed support structure; an integrally poured buttress wall is arranged at the fixed end of the floor, a steel beam arranged in an overhanging manner is arranged in the floor, an implicit diagonal bracing effect is formed on the floor, the floor can effectively resist the drooping trend of the cantilever end of the floor, the bearing capacity and stability of the floor are significantly improved, and the visual sense of the building body is avoided from being affected by the explicit diagonal bracing; the buttress wall is designed, the position of the post-poured belt of the support wall is lowered, the post-poured belt is moved away from the fixed end of the floor, that is, the load concentration position, and thus the post-poured belt is effectively prevented from cracking; when the bottom floor is poured, the lower surface of the bottom floor is taken as a horizontal reference, horizontal reference conversion is carried out, and large-area sloping is avoided due to the support of the formwork.

Description

Technical Field

[0001] This invention relates to the field of prefabricated building construction, specifically a prefabricated large cantilever insulated floor slab and its construction method. Background Technology

[0002] The large cantilever floor slab provides the building with a richer structural design and a stronger visual impact. At the same time, the large cantilever design also poses a greater challenge to the load-bearing capacity and stability of the floor slab. Especially in prefabricated construction, the connection between the cantilever floor slab and the post-cast wall is a weak point in the structural strength, and it is also the point where the floor slab load is the greatest. The overlap of the two greatly increases the risk of cracking of the post-cast strip.

[0003] The invention patent with application number CN202410931183.2 provides a large-span composite floor slab and a construction method for the floor slab. It uses autoclaved aerated concrete blocks as the built-in lightweight core material to effectively reduce the self-weight of the floor slab and thus reduce some of the load. Although this method has a certain effect, it only reduces some of the self-weight and has limited effect on improving the load-bearing capacity of the floor slab. Moreover, it does not solve the problem of easy cracking of the post-pouring strip.

[0004] The utility model patent with application number CN202220720142.5 adopts a method of extending the fixed end of the floor slab outward in the opposite direction to make it extend outward from the supporting wall, and setting diagonal bracing between the reverse extended end of the floor slab and the supporting wall to improve the stability and load-bearing capacity of the floor slab. However, whether diagonal bracing or diagonal bracing is used, the exposure of the supporting structure will affect the space utilization of the building structure and will greatly reduce the visual impact of the large cantilever structure. Summary of the Invention

[0005] This invention provides a prefabricated large cantilever insulated floor slab and its construction method, aiming to solve the problems of poor load-bearing capacity of cantilever structures and exposed supporting structures.

[0006] The technical solution is as follows:

[0007] A prefabricated large cantilever insulated floor slab includes a top slab, a bottom slab, and a pier wall. The pier wall is connected to the lower side of one end of the bottom slab, and the bottom slab and the pier wall form an angle greater than 90 degrees. The top slab is located above the bottom slab, and the lower surface of the top slab has the same slope as the bottom slab, while the upper surface is horizontal. The top slab and the bottom slab together form the main body of the floor slab.

[0008] The wall is equipped with pre-embedded rectangular steel pipe piles, and the floor slab is equipped with steel beams with the same slope as the bottom slab. The rectangular steel pipe piles have insertion holes for the ends of the steel beams to be inserted into. The fixed ends of the steel beams are inserted into the rectangular steel pipe piles. Several sets of rectangular steel pipe piles and steel beams are evenly distributed along the wall.

[0009] The floor slab is encased in autoclaved aerated concrete blocks.

[0010] The closer to the cantilever end of the floor slab, the greater the density of the autoclaved aerated concrete blocks.

[0011] The upper end of the rectangular steel pipe pile is inserted into the top slab.

[0012] The angle between the bottom plate and the pier wall is no greater than 95 degrees.

[0013] A construction method for a prefabricated large cantilever insulated floor slab includes the following steps:

[0014] Step 1: With the bottom slab horizontal and the pier wall inclined, set up the pier wall formwork and the bottom slab formwork. After the formwork is set up, tie the bottom slab reinforcement cage on the bottom slab formwork and tie the pier wall reinforcement cage inside the pier wall formwork. When tying the pier wall reinforcement cage, reserve the installation holes of the steel pipe piles at the position of the rectangular steel pipe piles and reserve the connecting steel bars at the bottom of the pier wall to connect with the supporting wall.

[0015] Step 2: After the reinforcement cages for the pier wall and the bottom slab are completed, insert the rectangular square pipe piles into the installation holes of the reinforcement cage for the pier wall, then lay the steel beams on the reinforcement cage for the bottom slab, and insert the end of the steel beams closest to the pier wall into the insertion holes on the side wall of the rectangular steel pipe piles.

[0016] Step 3: Lay autoclaved aerated concrete blocks on the bottom slab reinforcement cage, with the laying density gradually increasing from the fixed end to the cantilever end of the bottom slab. Then, insert precast filling reinforcement cages into the gaps between the autoclaved aerated concrete blocks and tie them to the bottom slab reinforcement cage for fixation.

[0017] Step 4: Pour the bottom slab concrete and the pier wall concrete and wait for them to solidify and take shape. The pouring height should be up to two-thirds of the height of the autoclaved aerated concrete blocks.

[0018] Step 5: Hoist the integrally formed bottom slab and pier wall onto the support wall. The top of the support wall is pre-embedded with columns corresponding to the rectangular steel pipe piles and connecting steel bars to align the pier wall with the support wall. The columns are inserted into the rectangular steel pipe piles one by one from the bottom of the pier wall. A space for a post-pouring strip is reserved between the bottom of the pier wall and the top of the support wall to temporarily support and position the pier wall and the bottom slab.

[0019] Step 6: Tie the connecting steel bars at the bottom of the pier wall to the connecting steel bars at the top of the supporting wall, and set up the formwork for the post-pouring strip. Then pour the post-pouring strip concrete. After the post-pouring strip concrete is poured, immediately pour concrete from the top of the rectangular steel pipe pile into the rectangular steel pipe pile. After the concrete is formed, the pier wall and the bottom slab are assembled and fixed with the supporting wall.

[0020] Step 7: Set up the side formwork of the top slab above the bottom slab, with the bottom slab serving as the bottom formwork of the top slab. Then, hoist the prefabricated top slab reinforcement cage onto the bottom slab and tie the bottom of the top slab reinforcement cage to the filling reinforcement cage and the ends to the pier wall reinforcement cage.

[0021] Step 8: Pour the top slab concrete. After the concrete has set, remove the formwork to complete the construction.

[0022] In steps one, three, and seven, shims are used to adjust the height and level of the reinforcing cage.

[0023] In step four, before pouring concrete, the upper end of the rectangular steel pipe pile is sealed.

[0024] This invention improves the strength of the fixed end of the floor slab by setting an integrally cast pier wall at the fixed end of the floor slab, inserting the steel beam end with the rectangular steel pipe pile, and thickening the fixed end of the floor slab, thereby greatly reducing the risk of cracking at the fixed end of the floor slab.

[0025] By using the upward-sloping bottom slab and the upward-sloping steel beams within the floor slab, a hidden diagonal bracing effect is created on the floor slab. This effectively resists the sagging tendency of the cantilevered end of the floor slab, significantly improving the load-bearing capacity and stability of the floor slab, while also avoiding the visual impact of visible diagonal bracing on the building's appearance.

[0026] By designing the pier wall and moving its position relative to the post-cast strip of the supporting wall downwards, the post-cast strip is moved away from the load concentration point, i.e., the fixed end of the floor slab. Then, by using rectangular steel pipe piles and columns to limit the pier wall and the floor slab, the load of the post-cast strip is distributed, thereby effectively preventing cracking of the post-cast strip.

[0027] When pouring the bottom slab, the lower surface of the bottom slab is used as the horizontal reference. By converting the horizontal reference, it is not necessary to set up formwork to make large-area slope, nor is it necessary to control the slope of the upper surface of the bottom slab through formwork. This not only realizes the upward structure of the bottom slab, but also greatly reduces the difficulty of formwork and pouring. When pouring the top slab, the pier wall is used as the vertical reference, and the bottom slab is used as the bottom formwork of the top slab. During pouring, the upper surface of the top slab naturally forms a horizontal surface, which serves as the horizontal bearing surface of the floor slab. Attached Figure Description

[0028] Figure 1 For the three-dimensional floor slab Figure 1 .

[0029] Figure 2 For the three-dimensional floor slab Figure 2 .

[0030] Figure 3 This is a bottom view of the floor slab.

[0031] Figure 4 for Figure 3 A cross-sectional view at position AA.

[0032] Figure 5 for Figure 3 A cross-sectional view at position BB in the middle.

[0033] Figure 6 This is a front sectional view of the assembly of the floor slab and walls.

[0034] Figure 7 This is the main view during construction steps one through three.

[0035] Figure 8 These are three-dimensional views of the construction process from steps one to three.

[0036] Figure 9 This is the main view during construction step four.

[0037] Figure 10 This is a 3D view of the construction process in step four.

[0038] Figure 11 This is the main view during construction in step seven.

[0039] Figure 12 This is a 3D view of the construction process in step seven.

[0040] Figure 13 This is the main view during construction step eight.

[0041] Figure 14 This is a 3D view of the construction process in step eight. Detailed Implementation

[0042] Referring to the accompanying drawings, the present invention includes a top slab 1, a bottom slab 2, and a pier wall 3. The pier wall 3 is connected to the lower side of one end of the bottom slab 2. The bottom slab 2 and the pier wall 3 are cast in one piece. The pier wall 3 is used to connect with the supporting floor slab. The bottom slab 2 and the pier wall 3 form an angle greater than 90 degrees. That is, when the bottom of the pier wall 3 is aligned with the top of the supporting wall, the cantilever end of the bottom slab 2 is slightly upturned. The top slab 1 is located above the bottom slab 2. The top slab 1 is cast in one piece. The lower surface of the top slab 1 has the same slope as the bottom slab 2, and the upper surface is horizontal. That is, the top slab 1 is a wedge shape with a thicker fixed end and a thinner cantilever end. The top slab 1 and the bottom slab 2 together form the main body of the floor slab. The main body of the floor slab is also a wedge shape with a thicker fixed end and a thinner cantilever end. The connection between the main body of the floor slab and the pier wall 3 of this structure forms a diagonal bracing effect, which can improve the anti-sag ability of the cantilever end of the cantilever structure. Moreover, the connection between the main body of the floor slab and the pier wall 3 is the main load-bearing point. Casting it in one piece and thickening it can improve its connection strength and increase its load-bearing capacity.

[0043] The pier wall 3 is equipped with embedded rectangular steel pipe piles 4. The floor slab body is equipped with steel beams 5 with the same slope as the bottom slab 2. The rectangular steel pipe piles 4 have insertion holes for the ends of the steel beams 5 to be inserted. The fixed end of the steel beam 5 is inserted into the rectangular steel pipe piles 4. The steel beam 5 is in a cantilevered state with the cantilever end slightly higher, providing auxiliary support for the floor slab body. Several sets of rectangular steel pipe piles 4 and steel beams 5 are evenly distributed along the wall. The lower end of the rectangular steel pipe piles 4 is open at the bottom of the pier wall 3. Vertical columns are embedded at the top of the supporting wall. When assembling the floor slab, the columns are inserted into the rectangular steel pipe piles 4. Concrete is poured into the rectangular steel beams 5 in subsequent processes. The columns and rectangular steel beams 5 cooperate to provide anti-overturning limit for the floor slab, greatly reducing the tensile load caused by the weight of the floor slab at the post-cast connection between the pier wall 3 and the supporting wall.

[0044] The floor slab is embedded with autoclaved aerated concrete blocks 6. The lightweight and porous nature of the autoclaved aerated concrete blocks 6 can reduce the weight of the floor slab while improving its sound insulation and heat insulation performance.

[0045] Since the bending moment load on the cantilevered floor slab is greater closer to the fixed end, the arrangement density of the autoclaved aerated concrete (AAC) blocks 6 is greater closer to the cantilever end of the floor slab. This results in a lower overall density of the floor slab closer to the cantilever end. In addition, the wedge-shaped structure of the floor slab shifts the center of gravity of the floor slab significantly towards the fixed end, reducing the bending moment load generated by the self-weight of the floor slab. Furthermore, fewer AAC blocks 6 are used near the fixed end, while more cast-in-place ordinary concrete is retained to ensure its strength and load-bearing capacity. This arrangement of the AAC blocks 6 is well-suited to the stress conditions of the floor slab.

[0046] The upper end of the rectangular steel pipe pile 4 is inserted into the top plate 1, connecting the pier wall 3 and the top plate 1.

[0047] The angle between the bottom slab 2 and the pier wall 3 is no greater than 95 degrees, meaning that the upward tilt of the bottom slab 2 relative to the horizontal plane is no greater than 5 degrees. This is to avoid excessive thickness at the fixed end of the floor slab, and also because this upward tilt is almost imperceptible to the naked eye when looking up at the floor slab from below, thus not affecting the visual experience.

[0048] The construction method for the aforementioned large cantilevered insulated floor slab includes the following steps:

[0049] Step 1, as follows Figure 7 and Figure 8 As shown, with the bottom slab 2 horizontal and the pier wall 3 inclined, the pier wall template 7 and the bottom slab template 8 are supported. Compared with the support method of the pier wall 3 being vertical and the bottom slab 2 being inclined, the difficulty of finding the slope of the large area of ​​the bottom slab template 8 is avoided. The bottom slab template 8 can be supported horizontally on the plane. Since the pier wall 3 has a small area, it is easy to find the slope, which greatly reduces the difficulty of supporting the template.

[0050] When setting up the formwork, you can either build scaffolding under the bottom slab formwork 8 for support, or you can set up the bottom slab formwork 8 on the ground and dig a trench at the wall 3 to set up the wall 7.

[0051] After the formwork is erected, the bottom slab reinforcement cage 9 is tied to the bottom slab formwork 8, and the pier wall reinforcement cage 10 is tied inside the pier wall formwork 7. When tying the pier wall reinforcement cage 10, the installation holes of the steel pipe piles are reserved at the position of the rectangular steel pipe piles 4, and the connecting steel bars for connection with the supporting wall are reserved at the bottom of the pier wall 3. The reinforcement cage can be prefabricated or tied on site.

[0052] Step two: After the pier wall 3 and the bottom slab reinforcement cage 9 are completed, insert the rectangular square pipe piles into the installation holes of the pier wall reinforcement cage 10, ensuring good contact between the bottom of the rectangular square pipe piles and the bottom formwork of the pier wall 3, to prevent the concrete from blocking the lower end of the rectangular steel pipe piles 4 during pouring; then lay the steel beams 5 on the bottom slab reinforcement cage 9, and insert the end of the steel beams 5 closest to the pier wall 3 into the insertion holes on the side wall of the rectangular steel pipe piles 4. Spacers can be used to provide auxiliary support and adjust the height of the steel beams 5; after the position of the rectangular steel pipe piles 4 is adjusted, weld them to the pier wall reinforcement cage 10 and the position of the steel beams 5 is adjusted, weld them to the bottom slab reinforcement cage 9 to prevent the rectangular steel pipe piles 4 and steel beams 5 from shifting during pouring.

[0053] Step 3: Lay the autoclaved aerated concrete (AAC) blocks 6 on the bottom slab reinforcement cage 9, with the laying density gradually increasing from the fixed end of the bottom slab 2 to the cantilever end. Then, insert precast reinforcing cages 11 into the gaps of the AAC blocks 6 and tie them to the bottom slab reinforcement cage 9. The precast reinforcing cages can limit the movement of the AAC blocks 6 to prevent them from shifting during concrete pouring. The height of the precast reinforcing cages is equal to or higher than the height of the AAC blocks 6 so that they can be tied to the top slab reinforcement cage 13.

[0054] Step four, as Figure 9 and Figure 10 As shown, the bottom slab concrete and the pier wall concrete are poured and allowed to solidify, with the pouring height reaching two-thirds of the submerged autoclaved aerated concrete block 6; the pier wall concrete and the bottom slab concrete are poured in one go.

[0055] Step 5: Hoist the integrally formed bottom slab 2 and the pier wall 3 onto the top of the supporting wall. The top of the supporting wall is pre-embedded with columns corresponding to the rectangular steel pipe piles 4 and connecting steel bars, so that the pier wall 3 is aligned with the supporting wall. The columns are inserted into the rectangular steel pipe piles 4 one by one from the bottom of the pier wall 3. A space for post-pouring strip is reserved between the bottom of the pier wall 3 and the top of the supporting wall. The pier wall 3 and the bottom slab 2 are temporarily supported and positioned. After hoisting into place, the pier wall 3 is in a vertical state, and the cantilever ends of the bottom slab 2 and the steel beam 5 are both in an upward cantilever state.

[0056] Step six: Tie the connecting steel bars at the bottom of the pier wall 3 to the connecting steel bars at the top of the supporting wall, and set up the formwork for the post-pouring strip. Then pour the post-pouring strip concrete. After the post-pouring strip concrete is poured, immediately pour concrete from the top of the rectangular steel pipe pile 4 into the rectangular steel pipe pile 4. After the concrete is formed, the pier wall 3 and the bottom slab 2 are assembled and fixed with the supporting wall. The rectangular steel pipe pile 4, together with the columns and concrete columns inside, limits the overturning of the pier wall 3 and the floor slab, which can greatly reduce the load on the post-pouring strip of the pier wall 3 and the supporting wall.

[0057] Step seven, as Figure 11 and Figure 12 As shown, a top plate side formwork 12 is erected above the bottom plate 2, and the bottom plate 2 serves as the bottom formwork of the top plate 1. Then, the prefabricated top plate reinforcement cage 13 is hoisted onto the bottom plate 2. The top plate reinforcement cage 13 is wedge-shaped, consistent with the top plate 1. The bottom of the top plate reinforcement cage 13 is tied to the filling reinforcement cage 11, and the end is tied to the pier wall reinforcement cage 10.

[0058] Step eight, as Figure 13 and Figure 14 As shown, the top slab concrete is poured, and the formwork is removed after the concrete has set, thus completing the construction. The top slab 1 serves as the surface layer of the floor slab, playing a leveling role and acting as the foundation for subsequent ground construction.

[0059] In steps one, three, and seven, shims are used to adjust the height and level of the reinforcing cage.

[0060] In step four, before pouring concrete, the upper end of the rectangular steel pipe pile 4 is sealed to prevent concrete from entering the rectangular steel pipe pile 4. This can be done by covering it with a cover plate or filling it with cloth.

[0061] In the above construction process, the application of formwork release agent, vibration during concrete pouring, and soaking of autoclaved aerated concrete blocks 6 were all carried out in accordance with conventional construction requirements.

[0062] If higher aesthetic requirements are considered, or if the installation of lighting fixtures and subsequent decorative construction require a level ceiling, the lower surface of the bottom panel 2 can be decoratively leveled by using a suspended ceiling.

[0063] This invention significantly reduces the risk of cracking at the fixed end of the floor slab and creates a hidden diagonal bracing effect on the floor slab. This effectively resists the sagging tendency of the cantilevered end of the floor slab, significantly improves the load-bearing capacity and stability of the floor slab, and avoids the visual impact of visible diagonal bracing on the building structure. The construction process of this invention greatly reduces the difficulty of construction.

Claims

1. A construction method for a prefabricated large cantilever insulated floor slab, characterized in that: The prefabricated large cantilever insulated floor slab includes a top slab (1), a bottom slab (2), and a pier wall (3). The pier wall (3) is connected to the lower side of one end of the bottom slab (2). The bottom slab (2) and the pier wall (3) form an angle greater than 90 degrees. The top slab (1) is located above the bottom slab (2). The lower surface of the top slab (1) has the same slope as the bottom slab (2), and the upper surface is horizontal. The top slab (1) and the bottom slab (2) together form the main body of the floor slab. The pier wall (3) is provided with a pre-embedded rectangular steel pipe pile (4), and the floor slab is provided with a steel beam (5) with the same slope as the bottom slab (2). The rectangular steel pipe pile (4) has a plug hole for the end of the steel beam (5) to be inserted, and the fixed end of the steel beam (5) is inserted into the rectangular steel pipe pile (4). The rectangular steel pipe pile (4) and the steel beam (5) are evenly distributed in several groups along the wall direction. The floor slab is embedded with autoclaved aerated concrete blocks (6). The closer to the cantilever end of the floor slab, the greater the arrangement density of the autoclaved aerated concrete blocks (6). The upper end of the rectangular steel pipe pile (4) is inserted into the top slab (1). The angle between the bottom slab (2) and the pier wall (3) is not greater than 95 degrees. Construction methods include: Step 1: With the bottom slab (2) horizontal and the pier wall (3) inclined, set up the pier wall template (7) and the bottom slab template (8). After the template is erected, the bottom plate reinforcement cage (9) is tied on the bottom plate template (8), and the pier reinforcement cage (10) is tied in the pier template (7). When tying the pier reinforcement cage (10), the installation hole of the steel pipe pile is reserved at the position of the rectangular steel pipe pile (4), and the connecting steel bar connected to the supporting wall is reserved at the bottom of the pier (3). Step 2: After the pier wall (3) and the bottom slab reinforcement cage (9) are completed, insert the rectangular square pipe pile into the installation hole of the pier wall reinforcement cage (10); then lay the steel beam (5) on the bottom slab reinforcement cage (9) and insert the end of the steel beam (5) near the pier wall (3) into the insertion hole of the side wall of the rectangular steel pipe pile (4); Step 3: Lay autoclaved aerated concrete blocks (6) on the bottom slab reinforcement cage (9). The laying density gradually increases from the fixed end to the cantilever end of the bottom slab (2). Then, insert prefabricated filling reinforcement cages (11) into the gaps of the autoclaved aerated concrete blocks (6) and tie them to the bottom slab reinforcement cage (9). Step 4: Pour the bottom slab concrete and the pier wall concrete and wait for them to solidify and take shape. The pouring height should be up to two-thirds of the submerged autoclaved aerated concrete blocks (6). Step 5: Hoist the integrally formed bottom plate (2) and the pier wall (3) onto the top of the supporting wall. The top of the supporting wall is pre-embedded with columns corresponding to the rectangular steel pipe piles (4) and connecting steel bars, so that the pier wall (3) is aligned with the supporting wall. The columns are inserted into the rectangular steel pipe piles (4) one by one from the bottom of the pier wall (3). A post-pouring strip space is reserved between the bottom of the pier wall (3) and the top of the supporting wall. The pier wall (3) and the bottom plate (2) are temporarily supported and positioned. Step 6: Tie the connecting steel bars at the bottom of the pier wall (3) to the connecting steel bars at the top of the supporting wall, and set up the formwork for the post-pouring strip. Then pour the post-pouring strip concrete. After the post-pouring strip concrete is poured, immediately pour concrete from the top of the rectangular steel pipe pile (4) into the rectangular steel pipe pile (4). After the concrete is formed, the pier wall (3) and the bottom plate (2) are assembled and fixed with the supporting wall. Step 7: Set up the top plate side formwork (12) above the bottom plate (2). The bottom plate (2) serves as the bottom formwork of the top plate (1). Then, hoist the prefabricated top plate steel cage (13) onto the bottom plate (2) and tie the bottom of the top plate steel cage (13) to the filling steel cage (11) and the end to the pier wall steel cage (10). Step 8: Pour the top slab concrete. After the concrete has set, remove the formwork to complete the construction.

2. The construction method of a prefabricated large cantilever insulated floor slab according to claim 1, characterized in that, In steps one, three, and seven, shims are used to adjust the height and level of the reinforcing cage.

3. The construction method of a prefabricated large cantilever insulated floor slab according to claim 1, characterized in that, In step four, before pouring concrete, the upper end of the rectangular steel pipe pile (4) is closed.

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