A prefabricated floor slab and a method for preparing the same

Abstract

The present invention relates to the field of building prefabricated parts, and in particular to a floor slab prefabricated part, comprising a body, the body having a longitudinal direction along the length direction and a transverse direction along the width direction, the body being provided with an upper steel mesh cage and a lower steel mesh cage, and a transverse pulling layer being provided between the upper steel mesh cage and the lower steel mesh cage in the body; the transverse pulling steel bar applies a prestress of 150-160MPa, and the embedded steel bar applies a prestress of 210-230MPa. It solves the technical problems of weak bearing capacity and easy deformation of existing prefabricated panels. Based on this, a preparation method of a floor slab prefabricated part is also proposed.

Description

Technical Field

[0001] The invention relates to the field of building prefabricated parts, in particular to a floor slab prefabricated part. Background Art

[0002] At present, in order to increase the construction speed and ensure the construction quality, many house components are made of prefabricated components, such as wall panels and floor panels of houses. Prefabricated reinforced concrete prefabricated floor panels are used. After the prefabricated floor panels are pre-processed and formed in the factory workshop, they are transported to the construction site for installation, which greatly shortens the construction period and reduces the project cost. For example, a prefabricated floor panel disclosed in Chinese Patent Publication No.: CN111155690A uses a prefabricated floor panel to be modularly assembled using prefabricated floor panel standard modules. The prefabricated floor panel standard module is a reinforced concrete rectangular plate as a whole. The prefabricated floor panel standard module is set on the upper flange of the steel beam. The prefabricated floor panel standard module is provided with accommodation notches at the intersection of the four corners and the column. A groove is provided on the side wall of the prefabricated floor panel standard module. One side outlet of the groove is on the upper surface of the prefabricated floor panel standard module. The side wall of the prefabricated floor panel standard module is also affixed with an outer steel plate. The outer steel plate is welded to the steel mesh inside the prefabricated floor panel standard module.

[0003] Factors that affect the quality of prefabricated parts mainly include concrete quality, steel distribution structure, molding process, etc. The applicant has conducted research on the quality performance of prefabricated panels, and proposed this solution to address the technical problems of existing prefabricated panels, such as weak bearing capacity and easy deformation. Summary of the invention

[0004] Therefore, in view of the above problems, the present invention proposes a prefabricated floor slab, which solves the technical problems of weak bearing capacity and easy deformation of the existing prefabricated slabs. Based on this, a preparation method of the prefabricated floor slab is also proposed.

[0005] To achieve the above object, the present invention adopts the following technical solution: a prefabricated floor slab, comprising a body, the body having a longitudinal direction along the length direction and a transverse direction along the width direction, the body being provided with an upper steel mesh cage and a lower steel mesh cage, and a transverse pulling layer being provided in the body between the upper steel mesh cage and the lower steel mesh cage;

[0006] The transverse tension layer is formed by a plurality of transverse tension steel bars spaced apart in the longitudinal direction, each transverse tension steel bar is provided with a plurality of supporting steel bars in the longitudinal direction, each supporting steel bar is arranged crosswise with the transverse tension steel bar, the minimum spacing between two adjacent transverse tension steel bars is set to D, the length of each supporting steel bar is 0.1-0.5D, and the transverse tension steel bar is subjected to a prestress of 150-160MPa;

[0007] The upper steel mesh cage includes a plurality of prestressed units arranged in the longitudinal direction, each prestressed unit includes two embedded steel bars buried in the body, an exposed steel pipe arranged outside the body, and a plurality of connection structures connecting the two embedded steel bars and the exposed steel pipe, each connection structure includes a first connection bar and a second connection bar connecting the exposed steel pipe and one of the embedded steel bars, and a third connection bar and a fourth connection bar connecting the exposed steel pipe and another embedded steel bar, the first connection bar, the second connection bar, the third connection bar, and the fourth connection bar are mutually connected at the exposed steel pipe to form a connection portion, and the embedded steel bar is applied with a prestress of 210-230MPa;

[0008] Both ends of each steel bar are bent toward the upper steel bar mesh cage to form a clamping portion for clamping the embedded steel bars, thereby fixing and supporting the position of the embedded steel bars.

[0009] Furthermore, the distance between the exposed steel pipe and the body is 10-50 mm.

[0010] Furthermore, the spacing between two adjacent connection parts of the same exposed steel pipe is 200-400 mm.

[0011] Furthermore, the diameters of the first connecting rib, the second connecting rib, the third connecting rib and the fourth connecting rib are 30%-60% of the diameter of the embedded steel bars.

[0012] Furthermore, a strength reinforcement unit is provided between two adjacent prestressed units and in the middle of the longitudinal direction of the main body. The structure of each strength reinforcement unit is the same as that of the prestressed unit. The length of the strength reinforcement unit is 20%-30% of the longitudinal length of the main body.

[0013] Furthermore, the lower steel mesh cage includes lower transverse steel bars and lower longitudinal steel bars which are arranged in a staggered manner in a horizontal and vertical manner in the main body, and each lower transverse steel bar is welded and connected to each lower longitudinal steel bar.

[0014] Furthermore, a plurality of supporting legs are arranged on the lower ends of the lower transverse reinforcement and / or the lower longitudinal reinforcement.

[0015] A method for preparing a prefabricated floor slab comprises the following steps:

[0016] The first step is to use a forming mold, the forming mold comprising a bottom plate, two transverse frames arranged on the bottom plate and two longitudinal frames arranged on the bottom plate, the two transverse frames can be mutually engaged with the two longitudinal frames to form a forming frame, the transverse frames are provided with transverse through holes for passing transverse pulling steel bars, and the longitudinal frames are provided with longitudinal through holes for passing embedded steel bars;

[0017] The second step is to set the lower steel mesh cage on the bottom plate, clamp the two transverse frames with one of the longitudinal frames, insert the transverse pulling steel bars into the transverse through holes of the two transverse frames, and make each steel bar face upward, insert one end of the embedded steel bar in the prestressed unit into the longitudinal through hole of the longitudinal frame, and make the embedded steel bar clamped on the clamping part formed by each steel bar, insert the other end of the embedded steel bar into the longitudinal through hole of the other longitudinal frame, and then clamp and fix the longitudinal frame with the two transverse frames;

[0018] The third step is to apply prestress to the transverse tension steel bars and the embedded steel bars respectively;

[0019] The fourth step is to pour the concrete and use a vibrator to treat the concrete to achieve uniform pouring;

[0020] The fifth step is demoulding after curing and hardening.

[0021] Furthermore, during demoulding, the prestress at both ends of the same transverse tension steel bar is eliminated at the same time, while the prestress of two adjacent transverse tension steel bars is not eliminated at the same time. When the prestress is eliminated, it is gradually eliminated from the longitudinal middle to the longitudinal sides.

[0022] Furthermore, during demoulding, the prestress at both ends of the same embedded steel bar is eliminated at the same time, and the prestress of the two embedded steel bars of the same prestressed unit is eliminated at the same time. When the prestress is eliminated, it is gradually eliminated from the middle to both sides in the horizontal direction.

[0023] By adopting the above technical solution, the beneficial effects of the present invention are:

[0024] 1. This scheme achieves the enhancement of the bearing capacity of the prefabricated board through the limitation of the structure of the steel bars and the layout of the steel bars, and also achieves the performance that the prefabricated board is not easy to deform after forming. Among them, the lower steel mesh cage mainly achieves the purpose of overall reinforcement, the upper steel mesh cage mainly plays the purpose of longitudinal reinforcement support, the transverse pulling layer mainly plays the purpose of transverse reinforcement support, and can also achieve the purpose of limiting the position of the upper steel mesh cage.

[0025] Among them, it is a better choice to set the prestress of the transverse tension steel bars at 150-160MPa and the prestress of the embedded steel bars at 210-230MPa.

[0026] Moreover, through the exposed steel pipe, the first connecting rib, the second connecting rib, the third connecting rib and the fourth connecting rib, the stability of the exposed steel pipe support can be effectively achieved. The exposed steel pipe here can not only play a reinforcement role similar to that of steel bars, but also form other functions, such as connection, line laying, etc.

[0027] 2. The distance between the exposed steel pipe and the main body is 10-50 mm, and the distance between two adjacent connection parts of the same exposed steel pipe is 200-400 mm. Such a setting can achieve better connection configuration and form a better layout of the steel network.

[0028] 3. The diameters of the first connecting rib, the second connecting rib, the third connecting rib and the fourth connecting rib are 30%-60% of the diameter of the embedded steel bar. The need for prestressing and partial deformation is taken into consideration here. Such a setting can make the first connecting rib, the second connecting rib, the third connecting rib and the fourth connecting rib have a certain degree of flexible micro-deformation, so as to achieve better prefabricated panel forming. Generally speaking, the spacing between two adjacent prestressed units should not be too small. Generally speaking, it will be set between 400-600mm. Such a spacing setting is more conducive to the force on the body after the prestressing is applied, but such a spacing is not very conducive to the control of the bending deformation in the middle area of ​​the body. The setting of the strength reinforcement unit can effectively reduce the occurrence of bending deformation in the middle area of ​​the body.

[0029] 4. The lower steel mesh cage can be set according to actual needs. It is better to set the lower horizontal steel bars and lower vertical steel bars in a staggered manner, so as to form a relatively uniform distribution state, so as to cooperate with the transverse pulling layer and the upper steel mesh cage to achieve effective support. In addition, the support feet can be set so that there is a gap between the lower steel mesh cage and the lower bottom surface of the body, so that the lower steel mesh cage is covered in the body, and the gap can be adjusted according to the height of the support feet.

[0030] 5. A method for preparing a prefabricated floor slab, using a forming mold, which can be used to realize the insertion of transverse tension steel bars and embedded steel bars, thereby realizing the application of prestress. Moreover, when demolding and eliminating prestress, the prestress at both ends of the same transverse tension steel bar is eliminated at the same time, and the prestress of two adjacent transverse tension steel bars is not eliminated at the same time. When eliminating prestress, it is gradually eliminated from the longitudinal middle to the longitudinal sides. The prestress at both ends of the same embedded steel bar is eliminated at the same time, and the prestress of the two embedded steel bars of the same prestressed unit is eliminated at the same time. When eliminating prestress, it is gradually eliminated from the transverse middle to the transverse sides. This can effectively improve the quality of the prefabricated floor slab. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the present invention.

[0032] Figure 2 yes Figure 1 Schematic diagram of the structure in a top-down view.

[0033] Figure 3 yes Figure 1 Schematic diagram of the structure of the right viewing state.

[0034] Figure 4 It is a structural schematic diagram of the coordination between the prestressed unit and the strength reinforcement unit.

[0035] Figure 5 It is a structural diagram of the formed frame, embedded steel bars and transverse tension steel bars.

[0036] Figure 6 It is a structural diagram of the coordination between the transverse tensioning steel bars, the tensioning nuts and the transverse frame.

[0037] Figure 7 It is a structural schematic diagram of the coordination between the clamping mechanism, the tensioning nut and the transverse pulling steel bar.

[0038] Figure 8 yes Figure 7 Enlarged view of point A in the middle.

[0039] Fig. 9 It is a structural schematic diagram of another implementation of the clamping mechanism.

[0040] Reference numerals:

[0041] 1. Main body; 2. Prestressed unit; 21. Embedded steel bars; 22. Exposed steel pipe; 23. Connection structure; 231. First connection bar; 232. Second connection bar; 233. Third connection bar; 234. Fourth connection bar; 24. Connection part; 31. Transverse pulling steel bar; 311. Threaded section; 32. Support steel bar; 33. Clamping part; 34. Tightening nut; 341. Recessed ring part; 41. Lower transverse steel bar; 42. Lower longitudinal steel bar; 43. Support foot; 5. Strength reinforcement unit; 61. Transverse frame; 611. Transverse through hole; 62. Longitudinal frame; 621. Longitudinal through hole; 71. Cylinder; 72. Sliding through hole; 73. Clamping sheet; 74. Spring; 75. Tightening ring body; 76. Magnetic attraction structure; 77. Magnetic line limiting body; 81. Tightening part; 82. Upper clamp body; 83. Lower clamp body. DETAILED DESCRIPTION

[0042] The present invention will now be further described with reference to the accompanying drawings and specific implementation methods.

[0043] refer to Figures 1 to 5 The present embodiment provides a floor slab prefabricated component, comprising a body 1, wherein the body 1 has a longitudinal direction along the length direction and a transverse direction along the width direction, the body 1 is provided with an upper steel mesh cage and a lower steel mesh cage, and a transverse pulling layer is provided in the body 1 between the upper steel mesh cage and the lower steel mesh cage;

[0044] The transverse tension layer is formed by a plurality of transverse tension steel bars 31 spaced apart in the longitudinal direction, each transverse tension steel bar 31 is provided with a plurality of supporting steel bars 32 in the longitudinal direction, each supporting steel bar 32 is arranged crosswise with the transverse tension steel bar 31, the minimum spacing between two adjacent transverse tension steel bars 31 is set to D, the length of each supporting steel bar 32 is 0.1-0.5D, and the transverse tension steel bars 31 are applied with a prestress of 150-160MPa;

[0045] The upper steel mesh cage includes a plurality of prestressed units 2 arranged in the longitudinal direction, each prestressed unit 2 includes two embedded steel bars 21 embedded in the body 1, an exposed steel pipe 22 arranged outside the body 1, and a plurality of connecting structures 23 connecting the two embedded steel bars 21 and the exposed steel pipe 22, each connecting structure 23 includes a first connecting rib 231 connecting the exposed steel pipe 22 and one of the embedded steel bars 21, a second connecting rib 232, and a third connecting rib 233 and a fourth connecting rib 234 connecting the exposed steel pipe 22 and another embedded steel bar 21, the first connecting rib 231, the second connecting rib 232, the third connecting rib 233, and the fourth connecting rib 234 are mutually connected at the exposed steel pipe 22 to form a connecting portion 24, and the embedded steel bars 21 are subjected to a prestress of 210-230MPa;

[0046] Both ends of each steel bar 32 are bent toward the upper steel bar mesh to form a clamping portion 33 for clamping the embedded steel bar 21 , thereby fixing and supporting the position of the embedded steel bar 21 .

[0047] The distance between the exposed steel pipe 22 and the body 1 is 10-50 mm. The distance between two adjacent connecting parts 24 of the same exposed steel pipe 22 is 200-400 mm. The diameters of the first connecting rib 231, the second connecting rib 232, the third connecting rib 233, and the fourth connecting rib 234 are 30%-60% of the diameter of the embedded steel bar 21.

[0048] A strength reinforcement unit 5 is provided between two adjacent prestressed units 2 and in the middle of the longitudinal direction of the body 1. The structure of each strength reinforcement unit 5 is the same as that of the prestressed unit 2. The length of the strength reinforcement unit 5 is 20%-30% of the longitudinal length of the body 1.

[0049] The lower steel mesh cage includes lower transverse steel bars 41 and lower longitudinal steel bars 42 arranged in a staggered manner in the body 1, and each lower transverse steel bar 41 is welded to each lower longitudinal steel bar 42. A plurality of support legs 43 are arranged on the lower ends of the lower transverse steel bars 41 and / or the lower longitudinal steel bars 42.

[0050] Above Figures 1 to 5 In the figure, the red double-dotted line shows the upper steel mesh cage, the blue dotted line shows the lower steel mesh cage, and the purple dotted line shows the transverse pulling layer.

[0051] In addition, a method for preparing a prefabricated floor slab based on the same inventive concept is also proposed, comprising the following steps:

[0052] The first step is to use a forming mold, which includes a bottom plate, two transverse frames 61 provided on the bottom plate, and two longitudinal frames 62 provided on the bottom plate. The two transverse frames 61 can be mutually engaged with the two longitudinal frames 62 to form a forming frame. The transverse frames 61 are provided with transverse through holes 611 for passing the transverse pulling steel bars 31, and the longitudinal frames 62 are provided with longitudinal through holes 621 for passing the embedded steel bars 21.

[0053] The second step is to set the lower steel mesh cage on the bottom plate, clamp the two transverse frames 61 with one of the longitudinal frames 62, insert the transverse pulling steel bars 31 into the transverse through holes 611 of the two transverse frames 61, and make each steel bar 32 face upward, insert one end of the embedded steel bar 21 in the prestressed unit 2 into the longitudinal through hole 621 of the longitudinal frame 62, and make the embedded steel bar 21 clamped on the clamping portion 33 formed by each steel bar 32, insert the other end of the embedded steel bar 21 into the longitudinal through hole 621 of the other longitudinal frame 62, and then clamp and fix the longitudinal frame 62 with the two transverse frames 61;

[0054] The third step is to apply prestress to the transverse tension steel bars 31 and the embedded steel bars 21 respectively;

[0055] The fourth step is to pour the concrete and use a vibrator to treat the concrete to achieve uniform pouring;

[0056] The fifth step is demoulding after curing and hardening.

[0057] In the third step, when applying prestress, a torsional force is simultaneously applied to the transverse tension reinforcement 31. When applying the torsional force, the torsional angle of the transverse tension reinforcement 31 is 10-30 degrees. The application of the torsional force will make the supporting reinforcement 32 on the transverse tension reinforcement 31 effectively support the embedded reinforcement 21 after demoulding, thereby achieving a better forming effect.

[0058] During demoulding, the prestress at both ends of the same transverse tension steel bar 31 is eliminated at the same time, and the prestress of two adjacent transverse tension steel bars 31 is not eliminated at the same time. When eliminating the prestress, it is gradually eliminated from the middle of the longitudinal direction to both sides of the longitudinal direction. During demoulding, the prestress at both ends of the same embedded steel bar 21 is eliminated at the same time, and the prestress of the two embedded steel bars 21 of the same prestressed unit 2 is eliminated at the same time. When eliminating the prestress, it is gradually eliminated from the middle of the transverse direction to both sides of the transverse direction.

[0059] refer to Figures 4 to 6, both ends of the transverse pulling steel bar 31 are provided with threaded sections 311, and the threaded sections 311 are connected with tensioning nuts 34, which are located on the outer side of the transverse frame 61 during molding to fix the transverse pulling steel bar 31. A recessed ring portion 341 is provided at the middle of the tensioning nut 34, and the recessed ring portion 341 is used for clamping the external steel bar tensioning device. When tightening and clamping, a clamping mechanism is used to achieve it. The clamping mechanism includes a cylinder 71, which is sleeved on the outer side of the circumference of the tightening nut 34. A sliding through hole 72 is opened on the side of the cylinder 71. A clamping sheet 73 is telescopically arranged in the sliding through hole 72. A spring 74 connected to the clamping sheet 73 is arranged on the sliding through hole 72. The clamping sheet 73 is clamped in the recessed ring portion 341 through the action of the spring 74. A tightening ring 75 for tightening is arranged on the cylinder 71. A magnetic attraction structure 76 is arranged on one side of the cylinder 71 close to the horizontal frame 61. The magnetic attraction structure 76 includes a magnet and a magnetic line limiting body 77 covering the side of the magnet except the side close to the horizontal frame 61. The magnetic line limiting body 77 is plastic or ceramic or other conventional materials.

[0060] Refer to Figure 7 The clamping mechanism may further include a tensioning portion 81, an upper clamping body 82 and a lower clamping body 83 rotatably disposed on the tensioning portion 81, the upper clamping body 82 and the lower clamping body 83 are clamped and engaged at the recessed ring portion 341, and a magnet may be used at the engaging portion to achieve magnetic attraction.

[0061] Correspondingly, a tensioning nut 34 and a corresponding clamping mechanism are also provided on the embedded steel bar 21 .

[0062] After demoulding, the tensioning nut 34 on the transversely pulled steel bar 31 continues to be tightened, and the tensioning nut 34 rotates 0.5-1 turns. Due to the application of torsional force, the torsional force can achieve better matching of the supporting steel bar 32 with the embedded steel bar 21, but the setting of the torsional force will cause the prestress to be partially lost after demoulding, and the tensioning nut 34 rotates 0.5-1 turns to achieve the supplement of prestress.

[0063] The beneficial effects of the present invention are:

[0064] 1. This scheme achieves the enhancement of the bearing capacity of the prefabricated board through the limitation of the structure of the steel bars and the layout of the steel bars, and also achieves the performance that the prefabricated board is not easy to deform after forming. Among them, the lower steel mesh cage mainly achieves the purpose of overall reinforcement, the upper steel mesh cage mainly plays the purpose of longitudinal reinforcement support, the transverse pulling layer mainly plays the purpose of transverse reinforcement support, and can also achieve the purpose of limiting the position of the upper steel mesh cage.

[0065] Among them, it is a better choice to set the prestress of the transverse tension steel bars at 150-160MPa and the prestress of the embedded steel bars at 210-230MPa.

[0066] Moreover, through the exposed steel pipe, the first connecting rib, the second connecting rib, the third connecting rib and the fourth connecting rib, the stability of the exposed steel pipe support can be effectively achieved. The exposed steel pipe here can not only play a reinforcement role similar to that of steel bars, but also form other functions, such as connection, line laying, etc.

[0067] 2. The distance between the exposed steel pipe and the main body is 10-50 mm, and the distance between two adjacent connection parts of the same exposed steel pipe is 200-400 mm. Such a setting can achieve better connection configuration and form a better layout of the steel network.

[0068] 3. The diameters of the first connecting rib, the second connecting rib, the third connecting rib and the fourth connecting rib are 30%-60% of the diameter of the embedded steel bar. The need for prestressing and partial deformation is taken into consideration here. Such a setting can make the first connecting rib, the second connecting rib, the third connecting rib and the fourth connecting rib have a certain degree of flexible micro-deformation, so as to achieve better prefabricated panel forming. Generally speaking, the spacing between two adjacent prestressed units should not be too small. Generally speaking, it will be set between 400-600mm. Such a spacing setting is more conducive to the force on the body after the prestressing is applied, but such a spacing is not very conducive to the control of the bending deformation in the middle area of ​​the body. The setting of the strength reinforcement unit can effectively reduce the occurrence of bending deformation in the middle area of ​​the body.

[0069] 4. The lower steel mesh cage can be set according to actual needs. It is better to set the lower horizontal steel bars and lower vertical steel bars in a staggered manner, so as to form a relatively uniform distribution state, so as to cooperate with the transverse pulling layer and the upper steel mesh cage to achieve effective support. In addition, the support feet can be set so that there is a gap between the lower steel mesh cage and the lower bottom surface of the body, so that the lower steel mesh cage is covered in the body, and the gap can be adjusted according to the height of the support feet.

[0070] 5. A method for preparing a prefabricated floor slab, using a forming mold, which can be used to realize the insertion of transverse tension steel bars and embedded steel bars, thereby realizing the application of prestress. Moreover, when demolding and eliminating prestress, the prestress at both ends of the same transverse tension steel bar is eliminated at the same time, and the prestress of two adjacent transverse tension steel bars is not eliminated at the same time. When eliminating prestress, it is gradually eliminated from the longitudinal middle to the longitudinal sides. The prestress at both ends of the same embedded steel bar is eliminated at the same time, and the prestress of the two embedded steel bars of the same prestressed unit is eliminated at the same time. When eliminating prestress, it is gradually eliminated from the transverse middle to the transverse sides. This can effectively improve the quality of the prefabricated floor slab.

[0071] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, it should be understood by those skilled in the art that various changes may be made to the present invention in form and details without departing from the spirit and scope of the present invention as defined by the appended claims, all of which are within the scope of protection of the present invention.

Claims

1. A prefabricated floor slab, characterized in that: The main body includes a longitudinal direction along the length direction and a transverse direction along the width direction, the main body is provided with an upper steel mesh cage and a lower steel mesh cage, and a transverse pulling layer is provided in the main body between the upper steel mesh cage and the lower steel mesh cage; The transverse tension layer is formed by a plurality of transverse tension steel bars spaced apart in the longitudinal direction, each transverse tension steel bar is provided with a plurality of supporting steel bars in the longitudinal direction, each supporting steel bar is arranged crosswise with the transverse tension steel bar, the minimum spacing between two adjacent transverse tension steel bars is set to D, the length of each supporting steel bar is 0.1-0.5D, and the transverse tension steel bar is subjected to a prestress of 150-160MPa; The upper steel mesh cage includes a plurality of prestressed units arranged in the longitudinal direction, each prestressed unit includes two embedded steel bars buried in the body, an exposed steel pipe arranged outside the body, and a plurality of connection structures connecting the two embedded steel bars and the exposed steel pipe, each connection structure includes a first connection bar and a second connection bar connecting the exposed steel pipe and one of the embedded steel bars, and a third connection bar and a fourth connection bar connecting the exposed steel pipe and another embedded steel bar, the first connection bar, the second connection bar, the third connection bar, and the fourth connection bar are mutually connected at the exposed steel pipe to form a connection portion, and the embedded steel bar is applied with a prestress of 210-230MPa; Both ends of each support steel bar are bent upward toward the steel mesh cage to form a clamping portion for clamping the embedded steel bars, thereby fixing and supporting the position of the embedded steel bars. The transversely pulled steel bars are subjected to torsional force, so that the support steel bars form a supporting effect on the embedded steel bars. The torsion angle of the transversely pulled steel bars is 10-30 degrees.

2. A prefabricated floor slab according to claim 1, characterized in that: The distance between the exposed steel pipe and the body is 10-50 mm.

3. The prefabricated floor slab according to claim 1, characterized in that: The distance between two adjacent connections of the same exposed steel pipe is 200-400mm.

4. The prefabricated floor slab according to claim 1, characterized in that: The diameters of the first connecting bar, the second connecting bar, the third connecting bar and the fourth connecting bar are 30%-60% of the diameter of the embedded steel bars.

5. The prefabricated floor slab according to claim 1, characterized in that: A strength reinforcement unit is arranged between two adjacent prestressed units and in the middle of the longitudinal direction of the main body. The structure of each strength reinforcement unit is the same as that of the prestressed unit. The length of the strength reinforcement unit is 20%-30% of the longitudinal length of the main body.

6. The prefabricated floor slab according to claim 1, characterized in that: The lower steel mesh cage comprises lower transverse steel bars and lower longitudinal steel bars which are arranged in a transverse and longitudinal staggered manner in the main body, and each lower transverse steel bar is connected by welding with each lower longitudinal steel bar.

7. A prefabricated floor slab according to claim 6, characterized in that: A plurality of supporting legs are arranged on the lower ends of the lower transverse reinforcement and / or the lower longitudinal reinforcement.

8. A method for preparing a prefabricated floor slab according to any one of claims 1 to 7, characterized in that: The following steps are involved: The first step is to use a forming mold, the forming mold comprising a bottom plate, two transverse frames arranged on the bottom plate and two longitudinal frames arranged on the bottom plate, the two transverse frames can be mutually engaged with the two longitudinal frames to form a forming frame, the transverse frames are provided with transverse through holes for passing transverse pulling steel bars, and the longitudinal frames are provided with longitudinal through holes for passing embedded steel bars; The second step is to set the lower steel mesh cage on the bottom plate, clamp the two transverse frames with one of the longitudinal frames, insert the transverse pulling steel bars into the transverse through holes of the two transverse frames, and make each steel bar face upward, insert one end of the embedded steel bar in the prestressed unit into the longitudinal through hole of the longitudinal frame, and make the embedded steel bar clamped on the clamping part formed by each steel bar, insert the other end of the embedded steel bar into the longitudinal through hole of the other longitudinal frame, and then clamp and fix the longitudinal frame with the two transverse frames; The third step is to apply prestress to the transverse tension steel bars and the embedded steel bars respectively; The fourth step is to pour the concrete and use a vibrator to treat the concrete to achieve uniform pouring; The fifth step is demoulding after curing and hardening.

9. A method for preparing a prefabricated floor slab according to claim 8, characterized in that: During demoulding, the prestress at both ends of the same transverse tension steel bar is eliminated at the same time, but the prestress of two adjacent transverse tension steel bars is not eliminated at the same time. When the prestress is eliminated, it is gradually eliminated from the longitudinal middle to the longitudinal sides.

10. A method for preparing a prefabricated floor slab according to claim 8, characterized in that: During demoulding, the prestress at both ends of the same embedded steel bar is eliminated at the same time, and the prestress of the two embedded steel bars of the same prestressed unit is eliminated at the same time. When the prestress is eliminated, it is gradually eliminated from the middle to both sides of the horizontal direction.

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