Fully assembled reinforced concrete floor slab connected by steel-concrete composite structure

Abstract

The present invention discloses a fully assembled reinforced concrete floor slab connected by a steel-concrete composite structure. It includes a prefabricated unit, the main body of which is a reinforced concrete prefabricated floor slab, including a double-layer bidirectional steel mesh and concrete poured therein; the double-layer bidirectional steel mesh includes a plurality of main and secondary direction steel bars, the main and secondary direction steel bars are arranged in parallel along the secondary direction of the prefabricated unit, and the main and secondary direction steel bars are vertically connected by tie bars; the main and secondary channel steel assemblies are arranged in the prefabricated unit, a part of the main and secondary channel steel assemblies are buried in the concrete and connected to the main and secondary direction steel bars, and the other part extends out of the concrete and is connected to the load-bearing beam. The fully assembled reinforced concrete floor slab described in the present invention is convenient, efficient, green, and environmentally friendly in construction, and the production and connection arrangements are efficient and compact, so as to achieve "one piece with multiple functions" and "make the best use of everything", and obtain structural performance that is no less than that of a fully cast-in-place reinforced concrete floor slab, with a high comprehensive cost performance.

Description

Technical Field

[0001] The invention relates to a prefabricated reinforced concrete floor slab of a construction project and a connection method thereof, and in particular to a fully assembled reinforced concrete floor slab connected by a steel-concrete composite structure. Background Art

[0002] The main component of the current prefabricated reinforced concrete structure is the prefabricated reinforced concrete floor slab, which mainly includes steel truss floor slab, steel truss PC floor slab (composite slab) and removable bottom formwork steel truss floor slab and other floor slab forms.

[0003] The existing prefabricated reinforced concrete floor slabs only make partial changes to the cast-in-place reinforced concrete floor slabs, that is, the steel mesh in the cast-in-place reinforced concrete floor slabs is changed to steel trusses, and the bottom formwork of the cast-in-place reinforced concrete floor slabs is changed to corrugated steel plates, detachable formworks or PC plates, etc. There are still a lot of operations such as laying and binding of slab surface steel bars and on-site pouring of a large amount of concrete. The phenomenon of environmental pollution caused by large-scale on-site wet operations cannot be eliminated, and there is still a big gap from the fully prefabricated and fully assembled goal of "factory production and on-site assembly".

[0004] How to make prefabricated reinforced concrete slabs have the structural mechanical properties of fully cast-in-place reinforced concrete slabs while achieving fully prefabricated and fully assembled construction is the goal that the industry has been pursuing. As far as the current research and development results are concerned, the connections between fully prefabricated reinforced concrete slabs have their own characteristics but also their own problems, which are reflected in the force performance and design: either the steel bar anchorage length or the steel bar lap length is insufficient, or the steel bar force transmission path is unclear, or additional stress concentration in the connection area, or the effective concrete cross-section is reduced, or the steel member protective layer is insufficient, or the concrete interface strength is insufficient, or the connection with the load-bearing member is not firm, etc., resulting in the weakening of the compression, tension, shear, bending bearing capacity and stiffness of the overall floor slab after assembly, which seriously affects its coordinated vertical structural system. functions; reflected in the construction: either the concave and convex prefabricated panels are difficult to splice, or the processing technology of special steel components is complicated, or a large number of steel components are welded on-site, or a large area is grouting, or the connection of steel bars or bolt hole calibration is difficult, or overhead welding, overhead bolting, etc., resulting in low construction efficiency and even lack of practical operability, and it is difficult to ensure the construction quality; reflected in the construction cost: either the amount of steel used is too large, or the quality requirements of the grouting material are high, or there are too many fine-machined steel components, or the prefabricated floor formwork is complicated to make, or the construction period is long, etc., resulting in a significant increase in construction costs and poor market acceptance. Summary of the invention

[0005] In order to solve the problems existing in the background technology and to achieve the structural mechanical properties of a fully cast-in-place reinforced concrete floor slab, the present invention provides a fully assembled reinforced concrete floor slab with excellent structural stress performance, convenient construction and good economy, which solves the problems encountered in the design, construction, cost and other aspects of the current assembled reinforced concrete floor slabs, and promotes the realization of control targets such as quality, environmental protection, efficiency and cost of assembled concrete structures.

[0006] The present invention is guided by structural engineering theory, especially composite structure theory, and attempts to solve the above technical problems according to current technical standards to maximize the full prefabrication and assembly of reinforced concrete floor slabs.

[0007] The main scheme of the present invention includes the following:

[0008] 1. A fully assembled reinforced concrete floor slab connected by a steel-concrete composite structure:

[0009] This includes the prefabricated units themselves;

[0010] The main body inside the prefabricated unit is a reinforced concrete prefabricated floor slab, which is mainly composed of a double-layer bidirectional steel mesh and concrete poured thereon; the double-layer bidirectional steel mesh includes multiple main direction steel bar groups and multiple secondary direction steel bar groups, each main direction steel bar group is arranged in parallel along the main direction of the prefabricated unit, each secondary direction steel bar group is arranged in parallel along the secondary direction of the prefabricated unit, the main direction steel bar group and the secondary direction steel bar group are arranged perpendicularly, and the main direction steel bar group and the secondary direction steel bar group are connected by tie bars; main channel steel components and secondary channel steel components are arranged around the prefabricated unit, a part of the main channel steel components and the secondary channel steel components are buried in concrete and connected to the main direction steel bar group and the secondary direction steel bar group of the double-layer bidirectional steel mesh, and the other part extends out of the concrete for connection with the load-bearing beam.

[0011] The main direction of the prefabricated unit is defined as the direction in which the prefabricated unit is connected to the load-bearing beam.

[0012] The main direction steel bar group is mainly composed of the main direction slab surface steel bars and the main direction slab bottom steel bars, which are arranged in parallel up and down respectively; the secondary direction steel bar group is mainly composed of the secondary direction slab surface steel bars and the secondary direction slab bottom steel bars, which are arranged in parallel up and down respectively; the main direction slab surface steel bars and the secondary direction slab surface steel bars are located on the same plane, and the main direction slab bottom steel bars and the secondary direction slab bottom steel bars are located on the same plane; wherein the secondary direction slab bottom steel bars and the concrete thereunder extend outward to form a cantilever slab, and a concrete oblique cut is made at the top corner of the outer end of the cantilever slab; tie steel bars are arranged in the double-layer bidirectional steel mesh, and both ends of the tie steel bars are connected between a main direction steel bar group and a primary direction steel bar group.

[0013] The double-layer bidirectional steel mesh is provided with a main channel steel component at the intersection between the main direction steel bar group and the secondary direction steel bar group at both ends of the main direction of the prefabricated unit; the double-layer bidirectional steel mesh is provided with a secondary channel steel component at the intersection between the main direction steel bar group and the secondary direction steel bar group at both ends of the secondary direction of the prefabricated unit.

[0014] The main channel steel assembly comprises a main channel steel upper flange plate, a main channel steel lower flange plate, a main channel steel web plate and a main channel steel stiffening plate; the main channel steel body is formed by the main channel steel upper flange plate, the main channel steel lower flange plate and the main channel steel web plate, the main channel steel stiffening plate is fixedly welded between the middle parts of the main channel steel upper flange plate and the main channel steel lower flange plate, and the main channel steel stiffening plate is welded and arranged perpendicular to the main channel steel web plate; the main channel steel assembly is divided into an inner extension section and an outer extension section with the main channel steel stiffening plate as the boundary, wherein the main channel steel web plate bolt holes are provided on the main channel steel web plate of the outer extension section, and the main channel steel web plate bolt holes are waist-shaped through holes along the vertical direction in the length direction; the inner extension section is cast and buried in concrete, and the main channel steel upper flange plate and the main channel steel lower flange plate of the inner extension section are respectively welded to the main direction plate surface steel bars and the main direction plate bottom steel bars.

[0015] The secondary channel steel assembly comprises a secondary channel steel upper flange plate, a secondary channel steel lower flange plate, a secondary channel steel web plate and a secondary channel steel stiffening plate; the main channel steel body is formed by the secondary channel steel upper flange plate, the secondary channel steel lower flange plate and the secondary channel steel web plate, the secondary channel steel stiffening plate is fixedly welded between the middle parts of the secondary channel steel upper flange plate and the secondary channel steel lower flange plate, and the secondary channel steel stiffening plate is welded and arranged perpendicular to the secondary channel steel web plate; the secondary channel steel assembly is divided into an inner extension section and an outer extension section with the secondary channel steel stiffening plate as the boundary, wherein the secondary channel steel web plate bolt holes are provided on the secondary channel steel web plate of the outer extension section, and the secondary channel steel web plate bolt holes are waist-shaped through holes along the vertical direction in the length direction; the inner extension section is cast and buried in concrete, and the secondary channel steel upper flange plate and the secondary channel steel lower flange plate of the inner extension section are welded to the secondary direction plate surface steel bars and the secondary direction plate bottom steel bars respectively.

[0016] The ends of the prefabricated units in the main direction are placed on the load-bearing beams, and the ends of the prefabricated units in the main direction are placed on both sides of the load-bearing beams respectively; the ends of two adjacent prefabricated units in the main direction located on both sides of the load-bearing beams and along the same main direction are connected by a main connecting plate, and concrete is poured and additional steel bars are set on the main direction plate surface; the ends of two adjacent prefabricated units in the secondary direction are connected by a secondary connecting plate, and concrete is poured and additional steel bars are set on the secondary direction plate surface.

[0017] The ends of two adjacent precast units on both sides of the load-bearing beam and along the same main direction are connected in the following manner:

[0018] In the main direction of the prefabricated unit, the main channel steel assemblies of the two prefabricated units are connected by a main connecting plate, and each main channel steel assembly and the main connecting plate are connected by high-strength bolts; the main connecting plate is a long strip steel plate, and the main connecting plate is provided with horizontal waist-shaped holes at both ends as main connecting plate bolt holes, a horizontal waist-shaped hole is provided in the middle as the main connecting plate long slot hole, and main connecting plate grooves are provided on the upper and lower side edges; the main connecting plate bolt holes at both ends are respectively connected to the main channel steel assemblies of the two prefabricated units through high-strength bolts, and the high-strength bolts are successively passed through the main channel steel web bolt holes of the main channel steel assemblies and the main connecting plate bolt holes of the main connecting plates and then tightened with nuts to fix the main channel steel assemblies and the main connecting plates of the prefabricated units.

[0019] In the secondary direction of the prefabricated unit, the secondary channel steel assemblies of the two prefabricated units are connected by a secondary connecting plate, and each secondary channel steel assembly and the secondary connecting plate are connected by high-strength bolts; the secondary connecting plate is a long strip steel plate, and the secondary connecting plate is provided with horizontal waist-shaped holes at both ends as secondary connecting plate bolt holes, a horizontal waist-shaped hole is provided in the middle as a secondary connecting plate long slot hole, and secondary connecting plate grooves are provided on the upper and lower side edges; the secondary connecting plate bolt holes at both ends are respectively connected to the secondary channel steel assemblies of the two prefabricated units through high-strength bolts, and the high-strength bolts are successively passed through the main channel steel web bolt holes of the secondary channel steel assembly and the secondary connecting plate bolt holes of the secondary connecting plate and then tightened with nuts to fix the secondary channel steel assemblies and the secondary connecting plates of the prefabricated units.

[0020] In the main direction of the prefabricated unit, the extended sections of the main channel steel assemblies of two adjacent prefabricated units are placed on the load-bearing beam to form a groove with the beam surface of the load-bearing beam as the bottom template and the sides of the two adjacent prefabricated units as the side templates, concrete is poured in the groove, and additional steel bars of the main direction plate surface are buried, the additional steel bars of the main direction plate surface are orthogonal to the main connecting plate and tied, thereby forming a connection area of ​​the steel-concrete composite structure; in the secondary direction of the prefabricated unit, the ends of the cantilever plates of two adjacent prefabricated units are tightly attached together to form a groove, concrete is poured in the groove, and additional steel bars of the secondary direction plate surface are buried, the additional steel bars of the secondary direction plate surface are orthogonal to the secondary connecting plate and tied, thereby forming a connection area of ​​the steel-concrete composite structure.

[0021] The load-bearing beam is a prefabricated reinforced concrete beam or an H-shaped steel beam;

[0022] When the load-bearing beam is a reinforced concrete precast beam, a shear stirrup is arranged between every two adjacent main connection plates, so that the shear stirrups and the main connection plates are arranged alternately, and each shear stirrup is fixedly embedded in the top of the reinforced concrete precast beam;

[0023] When the load-bearing beam is an H-shaped steel beam, a shear stud is arranged between every two adjacent main connecting plates, so that the shear studs and the main connecting plates are arranged alternately at intervals, and each shear stud is fixedly welded to the top surface of the upper flange of the H-shaped steel beam.

[0024] 2. Construction method of fully assembled reinforced concrete floor slab, including:

[0025] First, the prefabricated units are prefabricated in the factory. On site, the prefabricated units are hoisted above the load-bearing beams using the extended sections as steel supports. The prefabricated units are arranged between every two load-bearing beams. Multiple prefabricated units are arranged closely along the direction of the load-bearing beams. Both ends of each prefabricated unit along the main direction are placed on two load-bearing beams. Both ends of each prefabricated unit along the secondary direction are suspended and connected. The main connecting plate is connected between two adjacent prefabricated units on the same load-bearing beam in the main direction according to the connection structure between the prefabricated unit and the load-bearing beam, and then additional steel bars are set to tie the main direction plate surface. A groove with the load-bearing beam surface as the bottom template and the sides of the two adjacent prefabricated units as the side template is cast in place in the groove, and the continuity of concrete between the prefabricated units is achieved. The main connecting plate is connected between two adjacent prefabricated units along the secondary direction in the direction of the load-bearing beam according to the connection structure between the prefabricated unit and the load-bearing beam, and then additional steel bars are set to tie the secondary direction plate surface. Finally, the top surface of the beam and the cantilever plate are used as the bottom template to cast in place concrete, and the continuity of concrete between the prefabricated units is achieved.

[0026] The channel steel assembly of the present invention is made of finished channel steel as the main part, welded stiffening plates and web openings, and serves as a conversion component for connecting steel bars between prefabricated units, a support for prefabricated units, a bracket for cantilevered plates, and a shear member for connecting new and old concrete. The long slots opened in the connecting plate form upper and lower plate strips that serve as through steel bars, slurry holes when pouring concrete, shear members when in use to increase the bite force with concrete, and weaken the bending stiffness when installing high-strength bolts to improve the complete friction surface.

[0027] In addition to connecting the precast unit concrete, the post-cast joint concrete serves as a compressive material to constrain the connecting plates and high-strength bolts, as a fire-proof and anti-corrosion material to protect steel components and steel bars, and as a grouting material to fill the joints in the secondary direction of the unit.

[0028] When the calculated height of the beam section takes into account the thickness of the floor slab, that is, when the superposition effect of the precast concrete beam or the combined effect of the steel beam is considered, the shear stirrups on the top of the precast concrete beam also have the function of the stirrups of the superposed beam, and the slab stand steel bars also have the function of the upper force-bearing steel bars of the superposed beam; the shear studs welded above the steel beam flange and the slab stand steel bars participate in the bending resistance and crack control of the continuous beam at the support.

[0029] Compared with the prior art, the present invention has the following characteristics and beneficial effects:

[0030] The fully assembled reinforced concrete floor slab of the present invention is convenient and efficient in construction, and saves materials and energy.

[0031] The production and connection arrangement of the prefabricated units of the present invention are efficient and compact. Through reasonable combination and matching, the mechanical properties of steel, steel bars and concrete materials are fully utilized to obtain more superior structural performance, so as to achieve "one piece with multiple functions" and "fulfill the purpose of everything", with high comprehensive cost performance.

[0032] The structure of the present invention can avoid a large amount of manual welding work on site, solve the problem of bolt hole calibration, and greatly improve installation efficiency.

[0033] The prefabricated unit of the present invention is hoisted into place without adding temporary supports, additional templates, joint grouting or groove grouting; the entire construction work is completed on the floor, reducing labor intensity and improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a three-dimensional schematic diagram of the fully assembled reinforced concrete floor prefabricated unit.

[0035] Figure 2 Structural section of the prefabricated unit in the main direction.

[0036] Figure 3 Structural section of the prefabricated unit in the secondary direction.

[0037] Figure 4 Elevation view of channel steel assembly.

[0038] Figure 5 Section view of the connection of precast units in the main direction (precast beam supports).

[0039] Figure 6 Section view of the connection of precast units in the main direction (steel beam support).

[0040] Figure 7 Section view of precast unit connection in secondary direction.

[0041] Figure 8 Elevation drawing of connecting plate.

[0042] Fig. 9 3D schematic diagram of high-strength bolt connection.

[0043] Reference numerals:

[0044] 1 Precast reinforced concrete floor slab, 1.1 Concrete, 1.2 Main direction slab surface reinforcement, 1.3 Main direction slab bottom reinforcement, 1.4 Secondary direction slab surface reinforcement, 1.5 Secondary direction slab bottom reinforcement, 1.6 Tie reinforcement, 1.7 Cantilever slab, 1.8 Concrete cut;

[0045] 2 Main channel steel components, 2.1 Main channel steel upper flange plate, 2.2 Main channel steel lower flange plate, 2.3 Main channel steel web plate, 2.4 Main channel steel stiffening plate, 2.5 Main channel steel web plate bolt holes;

[0046] 3rd channel steel assembly, 3.1st channel steel upper flange plate, 3.2nd channel steel lower flange plate, 3.3rd channel steel web plate, 3.4th channel steel stiffener plate, 3.5th channel steel web plate bolt holes;

[0047] 4 Precast reinforced concrete beams, 4.1 Shear stirrups;

[0048] 5H steel beam, 5.1 steel beam upper flange, 5.2 shear studs;

[0049] 6 Main connecting plate, 6.1 Main connecting plate bolt hole, 6.2 Main connecting plate long slot hole, 6.3 Main connecting plate groove;

[0050] 7th connection plate, 7.1st connection plate bolt hole, 7.2nd connection plate slotted hole, 7.3rd connection plate groove;

[0051] 8 high-strength bolts, 8.1 washers, 8.2 nuts, 8.3 pads, 8.3.1 pad bolt holes;

[0052] 9: Additional reinforcement on the slab surface in the main direction, 10: Additional reinforcement on the slab surface in the secondary direction, 11: Cast-in-place concrete. DETAILED DESCRIPTION

[0053] The present invention will be further described below in conjunction with the accompanying drawings and specific implementations.

[0054] like Figure 1 As shown, the structure of the present invention mainly includes the fully assembled reinforced concrete floor slab prefabricated units themselves, the connections between the prefabricated units, and the connections between the prefabricated units and the load-bearing beams.

[0055] The prefab unit itself:

[0056] Fully assembled reinforced concrete floor prefabricated unit Figure 1 As shown, the internal body of the prefabricated unit is a reinforced concrete prefabricated floor slab 1, which is mainly composed of a double-layer bidirectional steel mesh and concrete 1.1 poured thereon, and the concrete 1.1 is poured inside the double-layer bidirectional steel mesh;

[0057] The double-layer bidirectional steel mesh includes multiple main direction steel bar groups and multiple secondary direction steel bar groups. Each main direction steel bar group is arranged in parallel along the main direction of the prefabricated unit, and each secondary direction steel bar group is arranged in parallel along the secondary direction of the prefabricated unit. The main direction and secondary directions of the prefabricated unit are orthogonal to each other, the main direction steel bar group and the secondary direction steel bar group are arranged perpendicular to each other, and the main direction steel bar group and the secondary direction steel bar group are connected by tie bars 1.6; main channel steel components 2 and secondary channel steel components 3 are arranged around the prefabricated unit, and a part of the main channel steel components 2 and the secondary channel steel components 3 are buried in concrete 1.1 and connected to the main direction steel bar group and the secondary direction steel bar group of the double-layer bidirectional steel mesh, and the other part extends out of concrete 1.1 for connection with the load-bearing beam.

[0058] The main direction reinforcement group is mainly composed of main direction slab surface reinforcement 1.2 and main direction slab bottom reinforcement 1.3 which are arranged in parallel up and down respectively, and the secondary direction reinforcement group is mainly composed of secondary direction slab surface reinforcement 1.4 and secondary direction slab bottom reinforcement 1.5 which are arranged in parallel up and down respectively, all main direction slab surface reinforcement 1.2 and all secondary direction slab surface reinforcement 1.4 are located on the same plane, and all main direction slab bottom reinforcement 1.3 and all secondary direction slab bottom reinforcement 1.5 are located on the same plane; the secondary direction slab bottom reinforcement 1.5 and the concrete 1.1 thereunder extend outwards to form a cantilever slab 1.7, and a concrete oblique cut 1.8 is made at the top corner of the outer end of the cantilever slab 1.7, see Figure 3 The double-layer bidirectional steel mesh is provided with tie bars 1.6, and both ends of the tie bars 1.6 are connected between a main direction steel bar group and a primary direction steel bar group.

[0059] In this way, the main direction plate surface steel bars 1.2, the main direction plate bottom steel bars 1.3, the secondary direction plate surface steel bars 1.4, and the secondary direction plate bottom steel bars 1.5 form a double-layer bidirectional steel mesh through the tie steel bars 1.6.

[0060] One end of the tie steel bar 1.6 is welded and connected at the intersection between the main direction slab surface steel bar 1.2 of the main direction steel bar group and the secondary direction slab surface steel bar 1.4 of the secondary direction steel bar group, and the other end of the tie steel bar 1.6 is welded and connected at the intersection between the main direction slab bottom steel bar 1.3 of the main direction steel bar group and the secondary direction slab bottom steel bar 1.5 of the secondary direction steel bar group.

[0061] The double-layer bidirectional steel mesh is provided with a main channel steel component 2 at the intersections between the main direction slab steel bars 1.2 of the main direction steel bar group and the secondary direction slab steel bars 1.4 of the secondary direction steel bar group at both ends of the main direction of the precast unit, that is, a main channel steel component 2 is connected and provided between the intersections between the main direction slab steel bars 1.2 of the main direction steel bar group and the secondary direction slab steel bars 1.4 of the secondary direction steel bar group and the intersections between the main direction slab bottom steel bars 1.3 of the main direction steel bar group and the secondary direction slab bottom steel bars 1.5 of the secondary direction steel bar group at both ends of the secondary direction of the precast unit;

[0062] The double-layer bidirectional steel mesh is provided with a secondary channel steel component 3 at the intersection between the main direction slab steel bars 1.2 of the main direction steel bar group and the secondary direction slab steel bars 1.4 of the secondary direction steel bar group at both ends of the secondary direction of the precast unit, that is, a secondary channel steel component 3 is provided at both ends of the secondary direction of the precast unit, and between the intersection between the main direction slab steel bars 1.2 of the main direction steel bar group and the secondary direction slab steel bars 1.4 of the secondary direction steel bar group, and between the main direction slab bottom steel bars 1.3 of the main direction steel bar group and the secondary direction slab bottom steel bars 1.5 of the secondary direction steel bar group.

[0063] The main channel steel assembly 2 comprises a main channel steel upper flange plate 2.1, a main channel steel lower flange plate 2.2, a main channel steel web plate 2.3 and a main channel steel stiffening plate 2.4;

[0064] The main channel steel stiffening plate 2.4 is welded to the main channel steel upper flange plate 2.1, the main channel steel lower flange plate 2.2, and the main channel steel web plate 2.3. The main channel steel body is formed by the main channel steel upper flange plate 2.1, the main channel steel lower flange plate 2.2, and the main channel steel web plate 2.3. The main channel steel stiffening plate 2.4 is fixedly welded between the main channel steel upper flange plate 2.1 and the middle part of the main channel steel lower flange plate 2.2. The main channel steel stiffening plate 2.4 is welded and arranged perpendicularly to the main channel steel web plate 2.3. The main channel steel stiffening plate 2.4, the main channel steel upper flange plate 2.1 / the main channel steel lower flange plate 2.2, and the main channel steel web plate 2.3 are arranged perpendicularly to each other.

[0065] The main channel steel component 2 is divided into an inner extension section and an outer extension section with the main channel steel stiffening plate 2.4 as the boundary. The main channel steel web plate 2.3 of the outer extension section is provided with main channel steel web plate bolt holes 2.5 for connecting adjacent prefabricated units. The main channel steel web plate bolt holes 2.5 are waist-shaped through holes with their length direction along the vertical direction. Figure 2 , Figure 4 ;

[0066] See Figure 2 At each main channel steel assembly 2, the inner extension section is cast and buried in the concrete 1.1, and the main channel steel upper flange plate 2.1 and the main channel steel lower flange plate 2.2 of the inner extension section are welded to the main direction plate surface steel bar 1.2 and the main direction plate bottom steel bar 1.3 respectively.

[0067] The secondary channel steel assembly 3 comprises a secondary channel steel upper flange plate 3.1, a secondary channel steel lower flange plate 3.2, a secondary channel steel web plate 3.3 and a secondary channel steel stiffening plate 3.4;

[0068] The secondary channel steel stiffening plate 3.4 is welded to the secondary channel steel upper flange plate 3.1, the secondary channel steel lower flange plate 3.2, and the secondary channel steel web plate 3.3. The secondary channel steel upper flange plate 3.1, the secondary channel steel lower flange plate 3.2, and the secondary channel steel web plate 3.3 constitute the main channel steel body. The secondary channel steel stiffening plate 3.4 is fixedly welded between the secondary channel steel upper flange plate 3.1 and the middle part of the secondary channel steel lower flange plate 3.2. The secondary channel steel stiffening plate 3.4 is welded and arranged perpendicularly to the secondary channel steel web plate 3.3. The secondary channel steel stiffening plate 3.4, the secondary channel steel upper flange plate 3.1 / the secondary channel steel lower flange plate 3.2, and the secondary channel steel web plate 3.3 are arranged perpendicularly to each other.

[0069] The secondary channel steel component 3 is divided into an inner extension section and an outer extension section with the secondary channel steel stiffener plate 3.4 as the boundary, wherein the secondary channel steel web plate 3.3 of the outer extension section is provided with secondary channel steel web plate bolt holes 3.5 for connecting adjacent prefabricated units, and the secondary channel steel web plate bolt holes 3.5 are waist-shaped through holes along the vertical direction in the length direction, as shown in FIG. Figure 3 , Figure 4;

[0070] See Figure 3 At each main channel steel component 2, the inner extension section is cast and buried in the concrete 1.1, and the secondary channel steel upper flange plate 3.1 and the secondary channel steel lower flange plate 3.2 of the inner extension section are welded to the secondary direction plate surface steel bars 1.4 and the secondary direction plate bottom steel bars 1.5 respectively.

[0071] The load-bearing beam is a prefabricated reinforced concrete beam 4 or an H-shaped steel beam 5. The H-shaped steel beam 5 may also be a steel beam with other cross-section forms such as channel steel and box steel. The H-shaped steel beam 5 is only an example.

[0072] The ends of the prefabricated units in the main direction are placed on the load-bearing beams, and the ends of a prefabricated unit along the main direction are placed on both sides of the load-bearing beams respectively; the ends of two adjacent prefabricated units in the main direction located on both sides of the load-bearing beams and along the same main direction are connected by a main connecting plate 6, and concrete 11 is poured and additional steel bars 9 are set on the main direction plate surface; the ends of two adjacent prefabricated units in the secondary direction are connected by a secondary connecting plate 7, and concrete 11 is poured and additional steel bars 10 are set on the secondary direction plate surface.

[0073] Connections between prefabricated units:

[0074] See Figure 5 , Figure 6 , in the main direction of the prefabricated unit, the main channel steel components 2 of the two prefabricated units are connected by a main connecting plate 6, and each main channel steel component 2 and the main connecting plate 6 are connected by high-strength bolts 8;

[0075] See Figure 8 The main connecting plate 6 is a long steel plate. Both ends of the main connecting plate 6 are provided with horizontal waist-shaped holes as main connecting plate bolt holes 6.1, the middle is provided with a horizontal waist-shaped hole as the main connecting plate long slot hole 6.2, and the upper and lower side edges are provided with main connecting plate grooves 6.3; the main connecting plate bolt holes 6.1 at both ends are respectively connected to the main channel steel components 2 of the two prefabricated units through high-strength bolts 8, and the high-strength bolts 8 pass through the main channel steel web bolt holes 2.5 of the main channel steel component 2 of a prefabricated unit and the main connecting plate bolt holes 6.1 at one end of the main connecting plate 6 from the inside to the outside of the main channel steel component 2, and then are tightened with nuts 8.2 to connect, so that one end of the main channel steel component 2 of the prefabricated unit is fixedly connected to the main connecting plate 6.

[0076] Similarly, see Figure 7 , in the secondary direction of the prefabricated unit, the secondary channel steel components 3 of the two prefabricated units are connected by a secondary connecting plate 7, and each secondary channel steel component 3 and the secondary connecting plate 7 are connected by a high-strength bolt 8;

[0077] See Figure 8The secondary connecting plate 7 is a long strip steel plate, and the secondary connecting plate 7 has horizontal waist-shaped holes at both ends as secondary connecting plate bolt holes 7.1, a horizontal waist-shaped hole in the middle as a secondary connecting plate long slot hole 7.2, and secondary connecting plate grooves 7.3 on the upper and lower side edges; the secondary connecting plate bolt holes 7.1 at both ends are respectively connected to the secondary channel steel components 3 of the two prefabricated units through high-strength bolts 8, and the high-strength bolts 8 pass through the main channel steel web bolt holes 2.5 of the secondary channel steel component 3 of a prefabricated unit and the secondary connecting plate bolt holes 7.1 at one end of the secondary connecting plate 7 from the inside to the outside of the secondary channel steel component 3, and then are tightened with nuts 8.2 to connect, so that one end of the secondary channel steel component 3 of the prefabricated unit is fixedly connected to the secondary connecting plate 7.

[0078] The main connecting plate long slot hole 6.2 is provided on the main connecting plate 6, which plays a multi-functional role of being used to bear the through steel bars, serving as the through steel bars, serving as the mortar hole, serving as the shear member to increase the bite force with the concrete, and weakening the bending stiffness to improve the complete friction surface. The same is true for the secondary connecting plate long slot hole 7.2 provided on the secondary connecting plate 7.

[0079] The main connecting plate grooves 6.3 are provided on the upper and lower edges of the main connecting plate 6, which play a multi-functional role in weakening the out-of-plane rigidity, allowing moderate bending out of the plane, reducing construction errors, and ensuring the integrity of the steel plate contact surface. The same is true for the secondary connecting plate grooves 7.3 provided on the upper and lower edges of the secondary connecting plate 7.

[0080] In addition to the matching nut 8.2, the high-strength bolt 8 is specially equipped with a standard washer 8.1 and a pad 8.3. The pad 8.3 is provided with a pad bolt hole 8.3.1 for the high-strength bolt 8 to pass through, and the hole diameter is 1.5 to 2 mm larger than the nominal diameter of the bolt.

[0081] In the main direction of the prefabricated unit, the high-strength bolt 8 passes through the bolt hole 8.3.1 of the pad, the bolt hole 2.5 of the web of the main channel steel, the bolt hole 6.1 of the main connecting plate, and the bolt hole 8.3.1 of the pad from the inside of the main channel steel, and the nut 8.2 is tightened on the outside of the main channel steel to complete the mechanical connection between the main channel steel assembly 2 and the main connecting plate 6. The same is true in the secondary direction of the prefabricated unit. Fig. 9 .

[0082] Connection between precast units and load-bearing beams:

[0083] In the main direction of the prefabricated unit, the extended sections of the main channel steel components 2 of the two adjacent prefabricated units are placed on the load-bearing beam to form a groove with the load-bearing beam surface as the bottom template and the side surfaces of the two adjacent prefabricated units as the side templates. Concrete 11 is poured in the groove, and the main direction plate surface additional steel bars 9 are buried. The main direction plate surface additional steel bars 9 are orthogonal to the main connecting plate 6 and tied. The main direction plate surface additional steel bars 9 are parallel to the load-bearing beam, thereby forming a connection area of ​​the steel-concrete composite structure. Figure 5 , Figure 6 ;

[0084] When the load-bearing beam is a reinforced concrete precast beam 4, a shear stirrup 4.1 is arranged between every two adjacent main connection plates 6, so that the shear stirrups 4.1 and the main connection plates 6 are alternately arranged, and each shear stirrup 4.1 is fixedly embedded in the top of the reinforced concrete precast beam 4;

[0085] When the load-bearing beam is an H-shaped steel beam 5 , a shear stud 5 . 2 is arranged between every two adjacent main connecting plates 6 , so that the shear studs 5 . 2 and the main connecting plates 6 are arranged alternately at intervals, and each shear stud 5 . 2 is fixedly welded to the top surface of the upper flange of the H-shaped steel beam 5 .

[0086] In the secondary direction of the precast unit, the ends of the cantilever plates 1.7 of two adjacent precast units are closely attached to form a groove, concrete 11 is poured in the groove, and additional steel bars 10 for the secondary direction plate surface are buried. The additional steel bars 10 for the secondary direction plate surface are vertically and orthogonally tied to the secondary connecting plate 7, thereby forming a connection area of ​​the steel-concrete composite structure. Figure 7 .

[0087] First, prefabricate the prefabricated units in the factory, and then hoist the prefabricated units on the top of the load-bearing beams using the extended sections as steel supports on site. Arrange the prefabricated units between every two load-bearing beams, and arrange multiple prefabricated units closely spaced along the direction of the load-bearing beams. Both ends of each prefabricated unit along the main direction are placed on two load-bearing beams, and both ends of each prefabricated unit along the secondary direction are suspended and connected.

[0088] The two adjacent prefabricated units on the same load-bearing beam along the main direction are connected with the main connecting plate 6 according to the connection structure between the prefabricated unit and the load-bearing beam, and then the additional steel bars 9 on the upper main direction plate surface are welded, and the groove with the load-bearing beam surface as the bottom template and the side surfaces of the two adjacent prefabricated units as the side template is cast in place concrete 11 in the groove, and the continuity of the concrete between the prefabricated units is achieved;

[0089] The main connecting plate 6 is connected between two adjacent prefabricated units along the secondary direction along the direction of the load-bearing beam according to the connection structure between the prefabricated unit and the load-bearing beam, and then additional steel bars 10 are welded on the secondary direction plate surface, and finally, the top surface of the beam and the cantilever plate are used as the bottom formwork for cast-in-place concrete 11, and the continuity of concrete between the prefabricated units is achieved.

[0090] The overall structure of the present invention realizes the penetration of steel bars between prefabricated units: through a line-surface combined force transmission path of "upper and lower steel bars → upper and lower flanges of channel steel → square-shaped friction surface → upper and lower steel plate strips → square-shaped friction surface → upper and lower flanges of channel steel → upper and lower steel bars", the steel bars between the prefabricated units are fully penetrated like the steel mesh of the fully cast-in-place reinforced concrete floor slab, without the need for indirect force transmission such as the anchoring force and shear force of concrete, thereby avoiding additional stress concentration in the connection area of ​​the prefabricated units.

[0091] like Figure 1 As shown, the number and spacing of the main channel steel components 2 and the secondary channel steel components 3 correspond to the main direction steel bars 1.2 and 1.3, and the secondary direction steel bars 1.4 and 1.5, respectively. The length of the inner extension section of the channel steel meets the double-sided weld length of the steel bar (5 times the steel bar diameter). The connection arrangement between the channel steel component and the plate steel bar is efficient and compact. On the one hand, the plate steel bar serves as the anchor steel bar of the channel steel component, effectively anchoring the channel steel component to the prefabricated unit. On the other hand, the channel steel component serves as a conversion component of the plate steel bar force transmission path, realizing continuous force transmission of the steel bars between the prefabricated units.

[0092] like Figure 2 , Figure 4 As shown, the inner side of the main channel steel stiffening plate 2.4 is flush with the outer edge of the prefabricated unit, serving as a side formwork for pouring concrete in the main channel steel, simplifying the formwork system; the main channel steel stiffening plate 2.4 is welded to the main channel steel web 2.3, the main channel steel upper flange plate 2.1, and the main channel steel lower flange plate 2.2, so that the extended section of the main channel steel assembly 2 becomes a steel support placed on the load-bearing beam, which is convenient and reliable to install in place without temporary support; the main channel steel web bolt holes 2.5 opened in the extended section of the main channel steel web 2.3 are vertical long slot holes, so that the main connecting plate 6 can be appropriately moved up and down during installation to cope with the construction errors and deformations of the prefabricated units connected at both ends of the connecting plate 6 when placed in the height direction (Z direction).

[0093] like Figure 3 , Figure 4 As shown, the outer side of the secondary channel steel stiffening plate 3.4 is flush with the outer edge of the prefabricated unit, and can serve as a side formwork for pouring concrete in the secondary channel steel, simplifying the formwork system; after the secondary channel steel stiffening plate 3.4 is welded with the secondary channel steel web 3.3, the secondary channel steel upper flange plate 3.1, and the secondary channel steel lower flange plate 3.2, the extended section of the secondary channel steel assembly 3 constitutes a steel corbel for supporting the lower cantilever plate 1.7, thereby improving the bearing capacity of the cantilever plate 1.7 and reducing damage during transportation and construction; the secondary channel steel web bolt hole 3.5 opened on the extended section of the secondary channel steel web 3.3 is a vertical long slot hole, so that the secondary connecting plate 7 can be appropriately moved up and down during installation to cope with the construction error and deformation of the prefabricated units connected at both ends of the connecting plate 7 in the height direction (Z direction).

[0094] like Figure 8As shown, the main connecting plate 6 is provided with a main connecting plate long slot hole 6.2 to form an upper and lower plate strip, and the effective area of ​​the upper and lower plate strip sections is respectively equivalent to the effective area of ​​the main direction plate surface steel bar 1.2 and the main direction plate bottom steel bar 1.3 connected thereto, and bears the function of passing through the steel bars; the main connecting plate bolt holes 6.1 are provided at the two end areas of the main connecting plate 6 as horizontal long slot holes, so that the main connecting plate 6 can be appropriately moved left and right during installation to cope with the construction error of the prefabricated unit connected to the main connecting plate 6 when arranged in the main direction (X direction); three main connecting plate grooves 6.3 are provided on the outer sides of the upper and lower plate strips of the main connecting plate 6, so that the main connecting plate 6 can be appropriately bent out of the plane by weakening the out-of-plane stiffness of the plate strip area of ​​the main connecting plate 6, so as to cope with the construction error of the prefabricated unit connected to the main connecting plate 6 when arranged in the secondary direction (Y direction), and ensure the integrity of the steel plate contact surface. The structure and function of the secondary connecting plate 7 are similar to those of the main connecting plate 6.

[0095] like Figure 4 , Figure 8 , Fig. 9 As shown, in an ideal case, the main channel steel web bolt hole 2.5 and the connecting plate bolt hole 6.1 overlap to form a "cross" shape. In an extreme case, the main channel steel web bolt hole 2.5 and the connecting plate bolt hole 6.1 overlap to form one of four "L" shapes each rotated 90 degrees, and the high-strength bolt 8 can smoothly pass through the overlapping area of ​​the two holes. Since the connecting piece is a long slot hole, the effective area of ​​the washer 8.1 is insufficient, so a pad 8.3 is specially added. The pad 8.3 has a pad bolt hole 8.3.1. The hole diameter is controlled to be 1.5 to 2 mm larger than the nominal diameter of the bolt according to national standards. Tighten the nut 8.2 to apply pressure to the pad 8.3, and the pressure is effectively transferred to the contact surface between the main connecting plate 6 and the extended section of the main channel steel web 2.3 through the pad 8.3 transition, generating friction and realizing the shear connection of the steel member.

[0096] In short, in order to cope with the allowable civil engineering errors in the three dimensions of up and down (Z direction), left and right (X direction), and front and back (Y direction) when prefabricated units are installed, structural measures such as opening long slots, grooves, and adding pads are taken for high-strength bolt connections to improve installation efficiency and ensure the quality of high-strength bolt connections.

[0097] Realize the continuity of concrete between precast units: learn from and improve the structure of post-cast strips to tightly combine the concrete of adjacent precast units. The steel sections, connecting plates, stirrups and studs in the grooves are used as shear members to improve the bite force of the interface between the precast unit concrete and the cast-in-place concrete. Assisted by the support bars and structural steel bars, the post-cast area becomes a steel-concrete composite structure with a higher connection strength than the currently commonly used post-cast strips.

[0098] like Figure 7As shown, in the secondary direction of the prefabricated unit, after the adjacent prefabricated units are hoisted into place, a groove is naturally formed, the cantilever plate 1.7 serves as the bottom template of the groove, and the end concrete oblique cut 1.8 forms a "V"-shaped small groove to facilitate the slurry to fill the joints, and the extended section of the secondary channel steel component 3 protrudes from the edge of the prefabricated unit, so that the edge of the groove forms a serrated profile; the extended section of the secondary channel steel component 3 serves as a shear member at the interface between the cast-in-place concrete 11 in the groove and the prefabricated unit, the upper and lower plate strips of the secondary connecting plate 7 serve as through steel bars, and the secondary direction plate surface additional steel bars 10 constrain the secondary connecting plate 7, and the entire post-cast strip forms a steel-reinforced concrete composite structure. The connection performance has surpassed the general construction post-cast strip, so that the prefabricated units are connected into an integral floor slab.

[0099] like Figure 5 , Figure 6 As shown, the "continuity" of the precast unit concrete in the main direction is similar to the "continuity" in the secondary direction. In addition, the precast unit needs to achieve effective connection with the load-bearing beam. After the adjacent precast units are hoisted in place, they are placed on the load-bearing beam, and a groove with the top of the beam as the bottom template is naturally formed. When the load-bearing beam is a precast concrete beam 4, the top of the load-bearing beam is pre-embedded with shear stirrups 1.4. When the load-bearing beam is a steel beam 5, shear studs 5.2 are welded above the upper flange 5.1 to achieve effective connection between the post-cast strip of the floor slab and the beam. The main direction of the plate surface is supplemented with steel bars 9 to constrain the main connecting plate 6 and shear stirrups 1.4. Cast-in-place concrete 11 is poured in the groove. The three new and old concrete interfaces are tightly interlocked, so that an integrated beam-slab system is formed between the precast units and between the precast units and the load-bearing beam.

[0100] The improved post-casting strip connection method of the present invention has mature technology, efficient construction, reliable quality, and realizes the real continuity of floor slab concrete. The floor slab connected by this method is "equivalent to cast-in-place", and its overall stress performance is higher than that of the floor slab connected by joint grouting or groove grouting or embedded parts welding.

[0101] The construction process of the present invention:

[0102] First, prefabricate the prefabricated units in the factory, and then hoist the prefabricated units on the top of the load-bearing beams using the extended sections as steel supports on site. Arrange the prefabricated units between every two load-bearing beams, and arrange multiple prefabricated units closely spaced along the direction of the load-bearing beams. Both ends of each prefabricated unit along the main direction are placed on two load-bearing beams, and both ends of each prefabricated unit along the secondary direction are suspended and connected.

[0103] The two adjacent prefabricated units on the same load-bearing beam along the main direction are connected with the main connecting plate 6 according to the connection structure between the prefabricated unit and the load-bearing beam, and then the additional steel bars 9 on the upper main direction plate surface are welded, and the groove with the load-bearing beam surface as the bottom template and the side surfaces of the two adjacent prefabricated units as the side template is cast in place concrete 11 in the groove, and the continuity of the concrete between the prefabricated units is achieved;

[0104] The main connecting plate 6 is connected between two adjacent prefabricated units along the secondary direction along the direction of the load-bearing beam according to the connection structure between the prefabricated unit and the load-bearing beam, and then additional steel bars 10 are welded on the secondary direction plate surface, and finally, the top surface of the beam and the cantilever plate are used as the bottom formwork for cast-in-place concrete 11, and the continuity of concrete between the prefabricated units is achieved.

[0105] Therefore, the welding operations of the present invention are all completed in the factory, such as the connection between the steel bars and the embedded steel components, the addition of stiffening ribs to the finished channel steel, etc.; the on-site assembly of the prefabricated units adopts conventional mechanical connections, i.e., high-strength bolt connections, to avoid a large amount of manual welding operations on site; the connection of high-strength bolts takes into account the errors of civil construction, solves the problem of bolt hole calibration, and greatly improves the installation efficiency.

[0106] The prefabricated units are hoisted into place using the extended sections of the embedded steel components as steel supports, without the need for additional temporary supports; the post-cast strip grooves use the top surface of the beam and the cantilever slab as the bottom formwork, without the need for additional formwork; the cast-in-place concrete in the grooves achieves the continuity of concrete between the prefabricated units, without the need for grouting of joints or grooves; the entire construction work is completed on the floor, reducing labor intensity and improving work efficiency.

Claims

1. A fully assembled reinforced concrete floor slab connected by a steel-concrete composite structure, characterized in that: Includes prefabricated units; The main body inside the prefabricated unit is a reinforced concrete prefabricated floor slab (1), and the reinforced concrete prefabricated floor slab (1) is mainly composed of a double-layer bidirectional steel mesh and concrete poured thereon; The double-layer bidirectional steel mesh comprises a plurality of main direction steel bar groups and a plurality of secondary direction steel bar groups, each main direction steel bar group is arranged in parallel along the main direction of the prefabricated unit, each secondary direction steel bar group is arranged in parallel along the secondary direction of the prefabricated unit, the main direction steel bar group and the secondary direction steel bar group are arranged perpendicularly, and the main direction steel bar group and the secondary direction steel bar group are connected by tie bars (1.6); A main channel steel component (2) and a secondary channel steel component (3) are arranged around the prefabricated unit, a portion of the main channel steel component (2) and the secondary channel steel component (3) are buried in the concrete and connected to the main direction steel bar group and the secondary direction steel bar group of the double-layer bidirectional steel mesh, and the other portion protrudes from the concrete to be connected to the load-bearing beam; The main direction steel bar group is mainly composed of main direction slab surface steel bars (1.2) and main direction slab bottom steel bars (1.3) which are arranged in parallel up and down respectively; the secondary direction steel bar group is mainly composed of secondary direction slab surface steel bars (1.4) and secondary direction slab bottom steel bars (1.5) which are arranged in parallel up and down respectively; the main direction slab surface steel bars (1.2) and secondary direction slab surface steel bars (1.4) are located on the same plane; the main direction slab bottom steel bars (1.3) and secondary direction slab bottom steel bars (1.5) are located on the same plane; the secondary direction slab bottom steel bars (1.5) and the concrete thereunder extend outwards to form a cantilever slab (1.7); and a concrete oblique cut (1.8) is made at the top corner of the outer end of the cantilever slab (1.7); tie steel bars (1.6) are arranged in the double-layer bidirectional steel mesh; the two ends of the tie steel bars (1.6) are connected between a main direction steel bar group and a primary direction steel bar group; The double-layer bidirectional steel mesh is provided with a main channel steel component (2) at the intersection between the main direction steel bar group and the secondary direction steel bar group at both ends of the main direction of the prefabricated unit; the double-layer bidirectional steel mesh is provided with a secondary channel steel component (3) at the intersection between the main direction steel bar group and the secondary direction steel bar group at both ends of the secondary direction of the prefabricated unit; The main channel steel assembly (2) comprises a main channel steel upper flange plate (2.1), a main channel steel lower flange plate (2.2), a main channel steel web plate (2.3) and a main channel steel stiffening plate (2.4); the main channel steel body is formed by the main channel steel upper flange plate (2.1), the main channel steel lower flange plate (2.2) and the main channel steel web plate (2.3); the main channel steel stiffening plate (2.4) is fixedly welded between the main channel steel upper flange plate (2.1) and the main channel steel lower flange plate (2.2), and the main channel steel stiffening plate (2.4) is welded and perpendicular to the main channel steel web plate. (2.3) arrangement; with the main channel steel stiffening plate (2.4) as the boundary, the main channel steel assembly (2) is divided into an inner extension section and an outer extension section, wherein the main channel steel web plate (2.3) of the outer extension section is provided with a main channel steel web plate bolt hole (2.5), and the main channel steel web plate bolt hole (2.5) is a waist-shaped through hole along the vertical direction in the length direction; the inner extension section is cast and buried in concrete, and the main channel steel upper flange plate (2.1) and the main channel steel lower flange plate (2.2) of the inner extension section are welded to the main direction plate surface steel bars (1.2) and the main direction plate bottom steel bars (1.3) respectively; The secondary channel steel assembly (3) comprises a secondary channel steel upper flange plate (3.1), a secondary channel steel lower flange plate (3.2), a secondary channel steel web plate (3.3) and a secondary channel steel stiffening plate (3.4); the secondary channel steel upper flange plate (3.1), the secondary channel steel lower flange plate (3.2) and the secondary channel steel web plate (3.3) constitute a main channel steel body, the secondary channel steel stiffening plate (3.4) is fixedly welded between the secondary channel steel upper flange plate (3.1) and the middle part of the secondary channel steel lower flange plate (3.2), and the secondary channel steel stiffening plate (3.4) is welded and perpendicular to the secondary channel steel web plate (3.3) arrangement; with the secondary channel steel stiffening plate (3.4) as the boundary, the secondary channel steel assembly (3) is divided into an inner extension section and an outer extension section, wherein the secondary channel steel web plate (3.3) of the outer extension section is provided with a secondary channel steel web plate bolt hole (3.5), and the secondary channel steel web plate bolt hole (3.5) is a waist-shaped through hole along the vertical direction in the length direction; the inner extension section is cast and buried in concrete, and the secondary channel steel upper flange plate (3.1) and the secondary channel steel lower flange plate (3.2) of the inner extension section are welded to the secondary direction plate surface steel bars (1.4) and the secondary direction plate bottom steel bars (1.5) respectively; The ends of two adjacent precast units located on both sides of the load-bearing beam and along the same main direction are connected in the following manner: In the main direction of the prefabricated unit, the main channel steel components (2) of the two prefabricated units are connected by a main connecting plate (6), and each main channel steel component (2) and the main connecting plate (6) are connected by a high-strength bolt (8); the main connecting plate (6) is a long strip steel plate, and the main connecting plate (6) is provided with horizontal waist-shaped holes at both ends as main connecting plate bolt holes (6.1), a horizontal waist-shaped hole in the middle as a main connecting plate long slot hole (6.2), and a main connecting plate groove (6.3) at the upper and lower side edges; the main connecting plate bolt holes (6.1) at both ends are respectively connected to the main channel steel components (2) of the two prefabricated units by high-strength bolts (8), and the high-strength bolts (8) are sequentially passed through the main channel steel web bolt holes (2.5) of the main channel steel components (2), the main connecting plate bolt holes (6.1) of the main connecting plate (6), and then tightened with nuts (8.2) to connect, so that the main channel steel components (2) of the prefabricated unit and the main connecting plate (6) are fixedly connected; In the secondary direction of the prefabricated unit, the secondary channel steel components (3) of the two prefabricated units are connected by a secondary connecting plate (7), and each secondary channel steel component (3) and the secondary connecting plate (7) are connected by a high-strength bolt (8); the secondary connecting plate (7) is a long strip steel plate, and the secondary connecting plate (7) is provided with horizontal waist-shaped holes at both ends as secondary connecting plate bolt holes (7.1), a horizontal waist-shaped hole in the middle as a secondary connecting plate long slot hole (7.2), and secondary connecting plate grooves (7.3) at the upper and lower side edges; the secondary connecting plate bolt holes (7.1) at both ends are respectively connected to the secondary channel steel components (3) of the two prefabricated units by high-strength bolts (8), and the high-strength bolts (8) are sequentially passed through the main channel steel web bolt holes (2.5) of the secondary channel steel components (3), the secondary connecting plate bolt holes (7.1) of the secondary connecting plate (7), and then tightened with nuts (8.2) to connect the secondary channel steel components (3) and the secondary connecting plate (7) of the prefabricated unit.

2. A fully assembled reinforced concrete floor slab connected by a steel-concrete composite structure according to claim 1, characterized in that: The end of the prefabricated unit in the main direction is placed on the load-bearing beam, and the ends of the prefabricated unit in the main direction are placed on both sides of the load-bearing beam respectively; The ends of two adjacent prefabricated units located on both sides of the load-bearing beam and along the same main direction are connected by a main connecting plate (6), and concrete is poured and additional steel bars (9) are arranged on the main direction plate surface; The ends of two adjacent prefabricated units along the secondary direction are connected via a secondary connecting plate (7), concrete is poured, and additional steel bars (10) are arranged on the secondary direction plate surface.

3. The fully assembled reinforced concrete floor slab connected by a steel-concrete composite structure according to claim 1, characterized in that: In the main direction of the prefabricated unit, the extended sections of the main channel steel components (2) of two adjacent prefabricated units are placed on the load-bearing beam to form a groove with the beam surface of the load-bearing beam as the bottom template and the side surfaces of the two adjacent prefabricated units as the side templates, concrete is poured in the groove, and the main direction plate surface additional steel bars (9) are buried, and the main direction plate surface additional steel bars (9) are orthogonal to the main connection plate (6) and tied, thereby forming a connection area of ​​the steel-concrete composite structure; In the secondary direction of the prefabricated unit, the ends of the cantilever plates (1.7) of two adjacent prefabricated units are tightly attached together to form a groove, concrete is poured in the groove, and additional steel bars (10) for the plate surface in the secondary direction are buried. The additional steel bars (10) for the plate surface in the secondary direction are orthogonal to the secondary connecting plate (7) and are tied together, thereby forming a connection area of ​​the steel-concrete composite structure.

4. The fully assembled reinforced concrete floor slab connected by a steel-concrete composite structure according to claim 3, characterized in that: The load-bearing beam is a prefabricated reinforced concrete beam (4) or an H-shaped steel beam (5); When the load-bearing beam is a reinforced concrete precast beam (4), a shear stirrup (4.1) is arranged between every two adjacent main connection plates (6), so that the shear stirrups (4.1) and the main connection plates (6) are arranged alternately at intervals, and each shear stirrup (4.1) is fixedly embedded in the top of the reinforced concrete precast beam (4); When the load-bearing beam is an H-shaped steel beam (5), a shear stud (5.2) is arranged between every two adjacent main connecting plates (6), so that the shear studs (5.2) and the main connecting plates (6) are arranged alternately at intervals, and each shear stud (5.2) is fixedly welded to the top surface of the upper flange of the H-shaped steel beam (5).

5. The construction method applied to the fully assembled reinforced concrete floor slab according to claim 1, characterized in that: Methods include: First, prefabricate the prefabricated units in the factory, and then hoist the prefabricated units on the top of the load-bearing beams using the extended sections as steel supports on site. Arrange the prefabricated units between every two load-bearing beams, and arrange multiple prefabricated units closely spaced along the direction of the load-bearing beams. Both ends of each prefabricated unit along the main direction are placed on two load-bearing beams, and both ends of each prefabricated unit along the secondary direction are suspended and connected. A main connecting plate (6) is connected between two adjacent prefabricated units along the main direction on the same load-bearing beam according to the connection structure between the prefabricated units and the load-bearing beam, and additional steel bars (9) are arranged and tied to the upper main direction plate surface, and a groove is formed with the load-bearing beam surface as the bottom template and the sides of the two adjacent prefabricated units as the side templates, and concrete is poured in the groove to achieve the continuity of concrete between the prefabricated units; A main connection plate (6) is connected between two adjacent prefabricated units in the secondary direction along the direction of the load-bearing beam according to the connection structure between the prefabricated unit and the load-bearing beam, and then additional steel bars (10) are arranged and tied to the plate surface in the secondary direction. Finally, concrete is cast in situ using the top surface of the beam and the cantilever plate as the bottom formwork, and the continuity of concrete between the prefabricated units is achieved.

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