Prefabricated cavity staircase and production and construction method thereof

Abstract

This invention relates to the field of prefabricated building technology and discloses a prefabricated cavity staircase and its production and construction method. The staircase includes prefabricated steps, a prefabricated base slab, and a reinforcing cage. The prefabricated steps and the prefabricated base slab are connected by the reinforcing cage. A cavity for accommodating a cast-in-place concrete layer is formed between the prefabricated steps and the base slab. The cavity has a casting hole at the upper end of the prefabricated steps and a seal at the lower end of the base slab. A first irregularly shaped installation portion extends from the lower end of the prefabricated steps, containing a first irregularly shaped connecting steel bar that connects to the lower end of the reinforcing cage. A second irregularly shaped installation portion extends from the upper end of the base slab, containing a second irregularly shaped connecting steel bar that connects to the upper end of the reinforcing cage. Therefore, this invention has the advantages of convenient transportation, simple operation, high work efficiency, high safety, and wide applicability.

Description

Technical Field

[0001] The invention relates to the technical field of building prefabrication, in particular to a prefabricated cavity staircase and a production and construction method thereof. Background Art

[0002] Since there are many deficiencies in cast-in-situ stairs, in recent years, the art has provided a variety of technical solutions for industrially manufacturing stair products in factories so that they can be directly installed on buildings for use.

[0003] Prefabricated stairs have been widely used in the field of prefabricated buildings due to their high degree of standardization, low production difficulty, and convenient construction and installation. However, the prefabricated stairs used in existing engineering practices generally use a large amount of component materials and are heavy, which will increase the production and transportation costs of the components accordingly; at the same time, the excessive weight of the components will also affect the selection of tower cranes in engineering construction, causing an increase in tower crane costs. These factors have affected the promotion and application of prefabricated stairs in some projects. Summary of the invention

[0004] The problem to be solved by the present invention is to provide a prefabricated cavity staircase and a production and construction method thereof, which are convenient to transport, simple to operate, high in work efficiency, high in safety and wide in application.

[0005] In order to solve the above technical problems, one aspect of the present invention provides a prefabricated cavity staircase, comprising a prefabricated step, a prefabricated base plate and a steel cage, wherein the prefabricated step is connected to the prefabricated base plate through the steel cage, the steel cage forms a cavity between the prefabricated step and the prefabricated base plate for accommodating a cast-in-place concrete layer, the cavity is provided with a cast-in-place hole at the upper end of the prefabricated step, and the cavity is provided with a seal at the lower end of the prefabricated base plate, a first special-shaped mounting portion extends from the lower end of the prefabricated step, a first special-shaped connecting steel bar is provided in the first special-shaped mounting portion, and the first special-shaped connecting steel bar is connected to the lower end of the steel cage, a second special-shaped mounting portion extends from the upper end of the prefabricated base plate, a second special-shaped connecting steel bar is provided in the second special-shaped mounting portion, and the second special-shaped connecting steel bar is connected to the upper end of the steel cage.

[0006] As a preferred solution of the prefabricated cavity staircase of the present invention, the outer side surface of the prefabricated steps is in a step shape.

[0007] As a preferred solution of the prefabricated cavity staircase of the present invention, the steel cage includes a two-way upper iron stress-bearing steel bar group, a two-way lower iron stress-bearing steel bar group and a plurality of vertical short bars, the two-way lower iron stress-bearing steel bar group is arranged on the prefabricated bottom plate, the two-way upper iron stress-bearing steel bar group is arranged on the prefabricated step, a plurality of vertical short bars are connected between the intersection nodes of the two-way lower iron stress-bearing steel bar group and the intersection nodes of the two-way upper iron stress-bearing steel bar group, and the vertical short bars are respectively perpendicular to the two-way upper iron stress-bearing steel bars and the two-way lower iron stress-bearing steel bars.

[0008] As a preferred embodiment of the prefabricated cavity staircase of the present invention, the bidirectional upper iron stress-bearing steel bar group includes a first upper iron stress-bearing steel bar and a second upper iron stress-bearing steel bar, the first upper iron stress-bearing steel bar is connected to the second upper iron stress-bearing steel bar in a criss-cross manner, the first upper iron stress-bearing steel bar and the second upper iron stress-bearing steel bar are both buried in the prefabricated step, and the second upper iron stress-bearing steel bar is partially exposed in the cavity; the bidirectional lower iron stress-bearing steel bar group includes a first lower iron stress-bearing steel bar and a second lower iron stress-bearing steel bar, the first lower iron stress-bearing steel bar is connected to the second lower iron stress-bearing steel bar in a criss-cross manner, the first lower iron stress-bearing steel bar and the second lower iron stress-bearing steel bar are both buried in the prefabricated bottom plate, and the second lower iron stress-bearing steel bar is partially exposed in the cavity.

[0009] As a preferred solution of the prefabricated cavity staircase of the present invention, the first special-shaped mounting portion is integrally formed with the prefabricated step, and the second special-shaped mounting portion is integrally formed with the prefabricated bottom plate.

[0010] As a preferred solution of the prefabricated cavity staircase of the present invention, the first special-shaped connecting steel bars are tied and connected to the steel cage, and the second special-shaped connecting steel bars are tied and connected to the steel cage.

[0011] As a preferred solution of the prefabricated cavity staircase of the present invention, the first special-shaped connecting steel bar matches the shape of the first special-shaped installation portion, and the second special-shaped connecting steel bar matches the shape of the second special-shaped installation portion.

[0012] Another aspect of the present invention provides a production and construction method for a prefabricated cavity staircase, comprising the following steps:

[0013] Step 1: making a steel cage; wherein the lower end of the steel cage is tied with a first special-shaped connecting steel bar, and the upper end of the steel cage is tied with a second special-shaped connecting steel bar;

[0014] Step 2: placing the steel cage on the step mold so that the first special-shaped connecting steel bar is arranged in the concrete filling area corresponding to the first special-shaped installation part in the step mold;

[0015] Step 3: pour concrete into the step mold until the concrete buries the bidirectional upper iron stress-bearing steel bar group of the steel cage;

[0016] Step 4: After the precast step reaches the concrete demoulding strength, the cast precast step is demoulded;

[0017] Step 5, flipping the demoulded prefabricated step and hoisting it to the base plate mold, so that the second special-shaped connecting steel bar is arranged in the concrete filling area corresponding to the second special-shaped installation part in the base plate mold;

[0018] Step 6: pour concrete into the bottom plate mold until the concrete buries the two-way lower iron stress-bearing steel bar group of the steel cage, so that the steel cage forms a cavity between the prefabricated bottom plate and the prefabricated step, and the cavity is provided with a cast-in-place hole at the upper end of the prefabricated step;

[0019] Step 7: After the prefabricated bottom plate reaches the concrete demoulding strength, the cast prefabricated bottom plate is demoulded to complete the prefabricated cavity staircase;

[0020] Step 8, transporting the prefabricated cavity staircase to the construction site;

[0021] Step nine, hoisting the prefabricated cavity staircase to the installation position, positioning the first special-shaped installation part and the second special-shaped installation part with the main structure and connecting them in a coordinated manner;

[0022] Step 10: pour concrete into the cavity of the prefabricated cavity staircase, wait for the concrete to solidify and take shape, and finally form a solid staircase.

[0023] As a preferred embodiment of the production and construction method of the prefabricated cavity staircase of the present invention, in step three, concrete is poured into the step mold until the concrete buries the bidirectional upper iron stress-bearing steel bar group, so that the bidirectional upper iron stress-bearing steel bar group is partially exposed in the cavity.

[0024] As a preferred embodiment of the production and construction method of the prefabricated cavity staircase of the present invention, in step six, concrete is poured into the bottom plate mold until the concrete buries the double-way lower iron stress-bearing steel bar group, so that the double-way lower iron stress-bearing steel bar group is partially exposed in the cavity.

[0025] Compared with the prior art, the prefabricated cavity staircase and the production and construction method thereof of the present invention have the following beneficial effects:

[0026] The prefabricated steps and prefabricated base plates of the present invention are cast separately and combined into a complete component through a steel cage, which can make the casting work more standardized, which is conducive to improving the quality of the prefabricated cavity stairs and improving the prefabrication production efficiency; the design of forming a cavity between the prefabricated steps and the prefabricated base plate greatly reduces the weight of the prefabricated cavity stairs, reduces the prefabrication cost, and is more convenient for the handling and transportation of the prefabricated cavity stairs. It has high safety and can greatly reduce the difficulty of hoisting the prefabricated cavity stairs, reduce the impact of the heavy hoisting weight on the selection of the tower crane, reduce the cost of the tower crane, and at the same time reduce the labor intensity of the workers and improve the installation efficiency; the design of the first special-shaped installation part and the second special-shaped installation part can be applied to different installation environments and meet different installation requirements. It can be seen that the present invention is convenient to transport, simple to operate, high in work efficiency, high in safety, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings of the embodiment are briefly introduced below.

[0028] Figure 1 It is a structural schematic diagram of a prefabricated cavity staircase provided by the present invention;

[0029] Figure 2 It is a schematic diagram of the assembly between the steel cage and the first special-shaped connecting steel bar and the second special-shaped connecting steel bar;

[0030] Figure 3 It is a structural diagram of the steel cage;

[0031] Figure 4 This is a schematic diagram of the structure after the prefabricated steps are cast;

[0032] Figure 5 This is a schematic diagram of the structure of the prefabricated cavity staircase after completion.

[0033] In the figure: 1. precast step, 2. precast bottom plate, 3. cavity, 31. cast-in-place hole, 32. seal, 4. steel cage, 41. vertical short reinforcement, 42. first upper iron stress-bearing steel bar, 43. second upper iron stress-bearing steel bar, 44. first lower iron stress-bearing steel bar, 45. second lower iron stress-bearing steel bar, 5. first special-shaped mounting part, 6. first special-shaped connecting steel bar, 7. second special-shaped mounting part, 8. second special-shaped connecting steel bar, 9. main structure. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like used in the present invention to indicate the orientation or position relationship is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0036] See also Figure 1 and Figure 2 As shown, a preferred embodiment of the present invention is a prefabricated cavity staircase, comprising a prefabricated step 1, a prefabricated base plate 2 and a steel cage 4, wherein the prefabricated step 1 is connected to the prefabricated base plate 2 through the steel cage 4, wherein the steel cage 4 forms a cavity 3 for accommodating a cast-in-place concrete layer between the prefabricated step 1 and the prefabricated base plate 2, wherein the cavity 3 is provided with a cast-in-place hole 31 at the upper end of the prefabricated step 1, and the cavity 3 is provided with a seal 32 at the lower end of the prefabricated base plate 2, wherein a first special-shaped mounting portion 5 is extended from the lower end of the prefabricated step 1, wherein a first special-shaped connecting steel bar 6 is provided in the first special-shaped mounting portion 5, and the first special-shaped connecting steel bar 6 is connected to the lower end of the steel cage 4, wherein a second special-shaped mounting portion 7 is extended from the upper end of the prefabricated base plate 2, wherein a second special-shaped connecting steel bar 8 is provided in the second special-shaped mounting portion 7, and the second special-shaped connecting steel bar 8 is connected to the upper end of the steel cage 4. Specifically, a side of the prefabricated step 1 away from the steel cage 4 is stepped, and the seal 32 is connected to the first special-shaped connecting steel bar 6 .

[0037] When installing the present invention, the prefabricated cavity staircase is hoisted to the required installation position on the construction site, the first special-shaped installation part 5 and the second special-shaped installation part 7 are positioned and connected with the main structure 9, and then concrete is poured into the cavity 3 to finally form a solid staircase.

[0038] Therefore, the prefabricated steps 1 and prefabricated base plate 2 of the present invention are cast separately and combined into a complete component through the steel cage 4, which can make the casting work more standardized, which is conducive to improving the quality of the prefabricated cavity staircase and improving the prefabrication production efficiency; the design of forming a cavity 3 between the prefabricated steps 1 and the prefabricated base plate 2 greatly reduces the weight of the prefabricated cavity staircase, reduces the prefabrication cost, and is more convenient for the handling and transportation of the prefabricated cavity staircase. It has high safety and can greatly reduce the difficulty of hoisting the prefabricated cavity staircase, reduce the impact of the heavy hoisting weight on the selection of the tower crane, reduce the cost of the tower crane, and at the same time reduce the labor intensity of the workers and improve the installation efficiency; the design of the first special-shaped installation part 5 and the second special-shaped installation part 7 can be applied to different installation environments and meet different installation requirements. It can be seen that the present invention is convenient to transport, simple to operate, high in work efficiency, high in safety, and has a wide range of applications.

[0039] For example, Figure 3 As shown, the steel cage 4 includes a two-way upper iron stress-bearing steel bar group, a two-way lower iron stress-bearing steel bar group and a plurality of vertical short bars 41. The two-way lower iron stress-bearing steel bar group is arranged on the prefabricated bottom plate 2, and the two-way upper iron stress-bearing steel bar group is arranged on the prefabricated step 1. A plurality of vertical short bars 41 are connected between the intersection nodes of the two-way lower iron stress-bearing steel bar group and the intersection nodes of the two-way upper iron stress-bearing steel bar group. The vertical short bars 41 are respectively perpendicular to the two-way upper iron stress-bearing steel bars and the two-way lower iron stress-bearing steel bars. With such a design, the vertical short bars 41 are arranged at a high density, which can strengthen the rigidity of the steel cage 4, so as to ensure that the prefabricated cavity staircase can be cast and prefabricated in stages, and can evenly play a shearing role, so as to ensure that the prefabricated cavity staircase and the cast-in-place concrete layer form an integral solid stress-bearing component with high stability.

[0040] Exemplarily, the bidirectional upper iron stress-bearing steel bar group includes a first upper iron stress-bearing steel bar 42 and a second upper iron stress-bearing steel bar 43, the first upper iron stress-bearing steel bar 42 and the second upper iron stress-bearing steel bar 43 are connected in a criss-cross manner, the first upper iron stress-bearing steel bar 42 and the second upper iron stress-bearing steel bar 43 are both buried in the prefabricated step 1, and the second upper iron stress-bearing steel bar 43 is partially exposed in the cavity 3; the bidirectional lower iron stress-bearing steel bar group includes a first lower iron stress-bearing steel bar 44 and a second lower iron stress-bearing steel bar 45, the first lower iron stress-bearing steel bar 44 and the second lower iron stress-bearing steel bar 45 are connected in a criss-cross manner, the first lower iron stress-bearing steel bar 44 and the second lower iron stress-bearing steel bar 45 are both buried in the prefabricated bottom plate 2, and the second lower iron stress-bearing steel bar 45 is arranged on the prefabricated bottom plate 2 and partially exposed in the cavity 3. With such a design, the second upper iron stress-bearing steel bar 43 is arranged on the precast step 1 and partially exposed in the cavity 3, which can increase the roughness of the concrete surface of the precast step 1, thereby increasing the shear resistance, so that the second upper iron stress-bearing steel bar 43 is connected between the precast step 1 and the cast-in-place concrete layer, and the connection firmness between the precast step 1 and the cast-in-place concrete layer is improved; the second lower iron stress-bearing steel bar 45 is arranged on the precast base plate 2 and partially exposed in the cavity 3, which can increase the roughness of the concrete surface of the precast base plate 2, thereby increasing the shear resistance, so that the second lower iron stress-bearing steel bar 45 is connected between the cast-in-place concrete layers of the precast base plate 2, and the connection firmness between the cast-in-place concrete layers of the precast base plate 2 is improved, thereby improving the firmness of the overall staircase, and improving stability and safety.

[0041] In this embodiment, the first special-shaped mounting portion 5 is integrally formed with the prefabricated step 1, and the second special-shaped mounting portion 7 is integrally formed with the prefabricated base plate 2. The first special-shaped mounting portion 5 and the prefabricated step 1 can be cast at the same time, and the second special-shaped mounting portion 7 and the prefabricated base plate 2 can be cast at the same time, which makes the production process of the prefabricated cavity staircase simpler, improves production efficiency, and reduces the labor intensity of workers.

[0042] Specifically, the first special-shaped connecting steel bar 6 is tied and connected to the steel cage 4, the second special-shaped connecting steel bar 8 is tied and connected to the steel cage 4, the first special-shaped connecting steel bar 6 matches the shape of the first special-shaped installation portion 5, and the second special-shaped connecting steel bar 8 matches the shape of the second special-shaped installation portion 7. Such a design can facilitate the connection of the first special-shaped connecting steel bar 6 and the second special-shaped connecting steel bar 8 with the steel cage 4, which is convenient to operate and improves work efficiency.

[0043] Based on the above-mentioned prefabricated cavity staircase, an embodiment of the present invention further provides a production and construction method of the prefabricated cavity staircase, comprising the following steps:

[0044] Step 1: make a steel cage 4; wherein, the lower end of the steel cage 4 is tied with a first special-shaped connecting steel bar 6, and the upper end of the steel cage 4 is tied with a second special-shaped connecting steel bar 8; the operation is convenient and the production efficiency is high.

[0045] Step 2: Place the steel cage 4 on the step mold so that the first special-shaped connecting steel bar 6 is arranged in the concrete filling area corresponding to the first special-shaped mounting part 5 in the step mold; thereby, the prefabricated cavity staircase has good load-bearing strength, and the first special-shaped mounting part 5 also has good load-bearing performance.

[0046] Step three, such as Figure 4 As shown, concrete is poured into the step mold until the concrete buries the bidirectional upper iron stress-bearing steel bar group of the steel cage; specifically, concrete is poured into the step mold until the concrete surface coincides with the plane where the central axis of the second upper iron stress-bearing steel bar 43 is located; the second upper iron stress-bearing steel bar 43 can be buried on the prefabricated step 1 and partially exposed in the cavity 3, so that the second upper iron stress-bearing steel bar 43 is connected between the prefabricated step 1 and the cast-in-place concrete layer, and the connection between the prefabricated step 1 and the cast-in-place concrete layer is firm, thereby improving the firmness of the overall staircase, and improving stability and safety.

[0047] Step 4: After the precast step 1 has reached the concrete demoulding strength, the cast precast step 1 is demoulded.

[0048] Step five, turn over the demoulding precast step 1 and lift it to the base plate mold, so that the second special-shaped connecting steel bar 8 is installed in the concrete filling area corresponding to the second special-shaped installation part 7 in the base plate mold; the operation is simple, the precast step 1 and the precast base plate 2 are cast separately, and combined into a complete component through the steel cage 4, which can make the casting work more standardized, the quality of the precast cavity stairs is high, and the precast production efficiency is high.

[0049] Step 6: Figure 5 As shown, concrete is poured into the base plate mold until the concrete embeds the bidirectional lower iron stress-bearing steel bar group of the steel cage, so that the steel cage 4 forms a cavity 3 between the precast base plate 2 and the precast step 1, and the cavity 3 is provided with a cast-in-place hole 31 at the upper end of the precast step 1; specifically, concrete is poured into the base plate mold until the concrete surface coincides with the plane where the central axis of the second lower iron stress-bearing steel bar 45 is located; the second lower iron stress-bearing steel bar 45 can be embedded in the precast base plate 2 and partially exposed in the cavity 3, so that the second lower iron stress-bearing steel bar 45 is connected between the precast base plate 2 and the cast-in-place concrete layer, and the connection between the precast base plate 2 and the cast-in-place concrete layer is firm, thereby improving the firmness of the overall staircase, and improving stability and safety.

[0050] Step seven, after the prefabricated base plate 2 is left to stand until the concrete demoulding strength is reached, the cast prefabricated base plate 2 is demoulded to complete the prefabricated cavity staircase; the design of forming a cavity 3 between the prefabricated steps 1 and the prefabricated base plate 2 greatly reduces the weight of the prefabricated cavity staircase and has a low prefabrication cost.

[0051] Step eight, transport the prefabricated cavity stairs to the construction site; due to the light weight of the prefabricated cavity stairs, the handling and transportation processes are convenient and safe, and can greatly reduce the difficulty of hoisting the prefabricated cavity stairs, reduce the impact of the heavy hoisting weight on the selection of the tower crane, reduce the cost of the tower crane, and at the same time reduce the labor intensity of the workers and improve the installation efficiency.

[0052] Step nine, hoist the prefabricated cavity staircase to the installation position, and the first special-shaped installation part 5 and the second special-shaped installation part 7 are both positioned and matched with the main structure 9; wherein the first special-shaped installation part 5 and the second special-shaped installation part 7 are both hinged or fixedly connected with the main structure 9; the design of the first special-shaped installation part 5 and the second special-shaped installation part 7 can be applied to different installation environments and meet different installation requirements. It can be seen that the present invention is convenient to transport, simple to operate, high in work efficiency, high in safety, and has a wide range of applications.

[0053] Step 10, pouring concrete into the cavity 3 of the prefabricated cavity staircase, and waiting for the pouring to solidify and form a solid staircase;

[0054] Among them, in embodiment 1, one side of the prefabricated cavity staircase is connected to the wall through a polystyrene board, and a steel membrane for sealing is set on the other side of the prefabricated cavity staircase, and then cast-in-place concrete is carried out into the cavity 3 in the prefabricated cavity staircase, and after the pouring and solidification are formed, the steel mold is removed to finally form a solid staircase; in embodiment 2, when the left and right sides of the prefabricated cavity staircase are not against the wall, steel membranes for sealing are set on the left and right sides of the prefabricated cavity staircase, and then cast-in-place concrete is carried out into the cavity 3 in the prefabricated cavity staircase, and after the pouring and solidification are formed, the steel mold is removed to finally form a solid staircase; such a design enables the prefabricated cavity staircase to form a solid staircase, achieving good load-bearing performance and strong stability.

[0055] In the description of the present invention, it should be understood that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" used in the present invention should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] The above disclosure is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A prefabricated cavity staircase, characterized in that: The invention comprises a prefabricated step, a prefabricated base plate and a steel cage, wherein the prefabricated step is connected to the prefabricated base plate through the steel cage, a cavity for accommodating a cast-in-place concrete layer is formed between the prefabricated step and the prefabricated base plate, the cavity is provided with a cast-in-place hole at the upper end of the prefabricated step, the cavity is provided with a seal at the lower end of the prefabricated base plate, a first special-shaped mounting portion is extended from the lower end of the prefabricated step, a first special-shaped connecting steel bar is arranged in the first special-shaped mounting portion, the first special-shaped connecting steel bar is connected to the lower end of the steel cage, a second special-shaped mounting portion is extended from the upper end of the prefabricated base plate, a first special-shaped connecting steel bar is arranged in the second special-shaped mounting portion, There is a second special-shaped connecting steel bar, which is connected to the upper end of the steel cage; the side of the prefabricated step away from the steel cage is stepped; the steel cage includes a two-way upper iron stress-bearing steel bar group, a two-way lower iron stress-bearing steel bar group and a plurality of vertical short bars, the two-way lower iron stress-bearing steel bar group is arranged on the prefabricated bottom plate, the two-way upper iron stress-bearing steel bar group is arranged on the prefabricated step, a plurality of vertical short bars are connected between the intersection nodes of the two-way lower iron stress-bearing steel bar group and the intersection nodes of the two-way upper iron stress-bearing steel bar group, and the vertical short bars are respectively perpendicular to the two-way upper iron stress-bearing steel bars and the two-way lower iron stress-bearing steel bars.

2. The prefabricated cavity staircase according to claim 1, characterized in that: The bidirectional upper iron stress-bearing steel bar group includes a first upper iron stress-bearing steel bar and a second upper iron stress-bearing steel bar, the first upper iron stress-bearing steel bar is connected to the second upper iron stress-bearing steel bar in a criss-cross manner, the first upper iron stress-bearing steel bar and the second upper iron stress-bearing steel bar are both buried in the prefabricated step, and the second upper iron stress-bearing steel bar is partially exposed in the cavity; the bidirectional lower iron stress-bearing steel bar group includes a first lower iron stress-bearing steel bar and a second lower iron stress-bearing steel bar, the first lower iron stress-bearing steel bar is connected to the second lower iron stress-bearing steel bar in a criss-cross manner, the first lower iron stress-bearing steel bar and the second lower iron stress-bearing steel bar are both buried in the prefabricated bottom plate, and the second lower iron stress-bearing steel bar is partially exposed in the cavity.

3. The prefabricated cavity staircase according to claim 1, characterized in that: The first special-shaped mounting portion is integrally formed with the prefabricated step, and the second special-shaped mounting portion is integrally formed with the prefabricated bottom plate.

4. The prefabricated cavity staircase according to claim 1, characterized in that: The first special-shaped connecting steel bar is tied and connected to the steel cage, and the second special-shaped connecting steel bar is tied and connected to the steel cage.

5. The prefabricated cavity staircase according to claim 1, characterized in that: The first special-shaped connecting steel bar matches the shape of the first special-shaped mounting portion, and the second special-shaped connecting steel bar matches the shape of the second special-shaped mounting portion.

6. The production and construction method of a prefabricated cavity staircase according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: making a steel cage; wherein the lower end of the steel cage is tied with a first special-shaped connecting steel bar, and the upper end of the steel cage is tied with a second special-shaped connecting steel bar; Step 2: placing the steel cage on the step mold so that the first special-shaped connecting steel bar is arranged in the concrete filling area corresponding to the first special-shaped installation part in the step mold; Step 3: pour concrete into the step mold until the concrete buries the bidirectional upper iron stress-bearing steel bar group of the steel cage; Step 4: After the precast step reaches the concrete demoulding strength, the cast precast step is demoulded; Step 5, flipping the demoulded prefabricated step and hoisting it to the base plate mold, so that the second special-shaped connecting steel bar is arranged in the concrete filling area corresponding to the second special-shaped installation part in the base plate mold; Step 6: pour concrete into the bottom plate mold until the concrete buries the two-way lower iron stress-bearing steel bar group of the steel cage, so that the steel cage forms a cavity between the prefabricated bottom plate and the prefabricated step, and the cavity is provided with a cast-in-place hole at the upper end of the prefabricated step; Step 7: After the prefabricated bottom plate reaches the concrete demoulding strength, the cast prefabricated bottom plate is demoulded to complete the prefabricated cavity staircase; Step 8, transporting the prefabricated cavity staircase to the construction site; Step nine, hoisting the prefabricated cavity staircase to the installation position, positioning the first special-shaped installation part and the second special-shaped installation part with the main structure and connecting them in a coordinated manner; Step 10: pour concrete into the cavity of the prefabricated cavity staircase, wait for the concrete to solidify and take shape, and finally form a solid staircase.

7. The production and construction method of a prefabricated cavity staircase according to claim 6 is characterized in that: In step three, concrete is poured into the step mold until the concrete buries the bidirectional upper iron stress-bearing steel bar group, so that the bidirectional upper iron stress-bearing steel bar group is partially exposed in the cavity.

8. The production and construction method of a prefabricated cavity staircase according to claim 6 is characterized in that: In step six, concrete is poured into the bottom plate mold until the concrete buries the double-way lower iron stress-bearing steel bar group, so that the double-way lower iron stress-bearing steel bar group is partially exposed in the cavity.

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