Concrete composite slab with hollow steel ribs and construction method thereof

Abstract

The present invention relates to the technical field of concrete composite slab casting, and specifically to a concrete composite slab with hollow steel ribs and a construction method thereof. The concrete composite slab comprises a prefabricated layer and a cast-in-place layer, and has the following beneficial effects: by using longitudinal hollow steel ribs to replace the steel trusses of the traditional composite slab, the rigidity and bearing capacity of the structure are enhanced, and the prefabricated bottom plate of the composite slab can be prevented from cracking during transportation and hoisting; and this structure can reduce the plate thickness of the prefabricated bottom plate of the composite slab, reduce the deadweight of the prefabricated bottom plate of the composite slab, and make the transportation and hoisting of the composite slab more efficient; during the hoisting construction, less or no lower support can be used, which reduces the construction difficulty and increases the construction efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of concrete composite slab casting, in particular to a concrete composite slab with hollow steel ribs and a construction method thereof. Background Art

[0002] Concrete composite slabs are assembled integral floor slabs composed of prefabricated slabs and cast-in-place reinforced concrete layers, and are widely used in existing prefabricated buildings. Existing concrete composite slabs mainly use steel truss concrete composite slabs, which use steel trusses to improve the overall rigidity of the composite slabs and prevent the composite slabs from cracking; however, the rigidity increase of the steel trusses after being buried in the concrete bottom slab is limited, and the connection stability between the trusses and the bottom slab is not high, making the concrete composite slabs easy to crack during transportation and hoisting; and the bearing capacity of this composite slab is not large, and a large number of vertical supports must be set during its construction.

[0003] In order to solve the above problems, the prior art generally adopts ribbed concrete composite slabs, and the overall rigidity of the structure is enhanced by adding concrete ribs to prevent the composite slab from cracking and increase the bearing capacity of the composite slab. Although this structure can play a role in preventing the bottom plate from cracking to a certain extent, adding concrete ribs on the bottom plate will increase the deadweight of the composite slab, and a larger bottom plate support is still required during construction, which increases the difficulty of constructing the composite slab and reduces the construction efficiency. In addition, this structure is not suitable for floor structures with larger spans. Summary of the invention

[0004] The object of the present invention is to provide a concrete composite slab with hollow steel ribs and a construction method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A concrete composite slab with hollow steel ribs, the concrete composite slab comprising:

[0007] A prefabricated layer, wherein a hollow steel rib assembly and a lower steel mesh assembly are arranged in the middle of the prefabricated layer, wherein the lower steel mesh assembly is composed of a lower longitudinal beam and a lower transverse beam connected in a crisscross manner, wherein the hollow steel rib assembly is composed of a lower frame, an upper frame and a connecting plate, wherein the connecting plate is clamped and fixed between the lower frame and the upper frame, wherein a vertical pipe is vertically arranged at the connection position of the lower longitudinal beam and the lower transverse beam, wherein the lower longitudinal beam penetrates the side wall of the lower frame, and wherein a lower vertical and horizontal positioning hole group which cooperates with the lower longitudinal beam and the lower transverse beam to penetrate and plug in is arranged on the outer wall of the vertical pipe;

[0008] Cast-in-place layer, the cast-in-place layer and the prefabricated layer are both cast by concrete, an upper steel mesh assembly is arranged in the cast-in-place layer, the upper steel mesh assembly is composed of an upper longitudinal beam and an upper transverse beam, the upper longitudinal beam is inserted through the upper frame, and an upper longitudinal and transverse positioning hole group is arranged vertically and horizontally on the arc outer wall of the upper end of the vertical pipe to cooperate with the upper longitudinal beam and the upper transverse beam.

[0009] Preferably, a positioning base is provided at the lower end of the riser, and a stud threadedly connected to the lower end port of the riser is provided at the upper end of the positioning base. The cast-in-place layer and the prefabricated layer are cast in a casting mold, and a casting inner cavity is provided in the casting mold. The inner wall at the lower end of the casting inner cavity is provided with a positioning groove that cooperates with the positioning base.

[0010] Preferably, both ends of the upper frame are provided with 45-degree chamfered cuts, the lower end surface of the upper frame and the upper end surface of the lower frame are provided with linearly distributed plug rods, and the upper and lower end surfaces of the connecting plate are provided with plug holes, and the plug rods are plugged into the plug holes.

[0011] Preferably, the outer side wall of the connecting plate is provided with a fixed bias rod which is arranged parallel to and offset from the lower longitudinal beam, the arc outer wall of the vertical pipe is provided with a positioning collar which is slidably sleeved on the fixed bias rod, and a flexible connecting piece is provided between the positioning collar and the outer wall of the vertical pipe.

[0012] Preferably, the outer edge of the upper end of the prefabricated layer is provided with a chamfer, the end of the fixed deflection rod is connected with a frame-shaped chamfered strip, and the chamfered inclined surface of the lower end of the chamfered strip fits with the chamfer of the prefabricated layer.

[0013] Preferably, the upper frame is provided with an upper through hole for mating with the upper longitudinal beam, and the side wall of the lower frame is penetrated with a lower through hole for mating with the lower longitudinal beam, and the inner diameter of the lower through hole is smaller than the inner diameter of the upper through hole.

[0014] Preferably, a pair of through long grooves are provided on both the upper frame and the lower frame, and the through long grooves on the upper frame are connected to the hoisting components of the hoisting equipment.

[0015] Preferably, a circular annular protrusion is provided on the positioning base, and the positioning base is disassembled after the prefabricated layer is cast, and a supporting base is placed in the positioning groove after disassembly, and an upwardly concave anti-overflow groove is formed in the prefabricated layer at a position corresponding to the circular annular protrusion.

[0016] Preferably, an open groove is transversely penetrated through the arc outer wall of the upper end of the riser, the open groove is located at the upper end of the prefabricated layer, and the open groove is located at the lower end of the upper vertical and horizontal positioning hole group.

[0017] A construction method for the concrete composite slab with hollow steel ribs, comprising the following steps:

[0018] Prefabricated components are assembled, and the upper frame and the lower frame are assembled through the connecting plate to form a hollow steel rib component. The linearly distributed lower longitudinal beams are inserted into the lower frame, and multiple groups of vertical pipes are sleeved along the lower longitudinal beams and the fixed eccentric rods. The lower transverse beams are inserted at the positions of the vertical pipes corresponding to the lower longitudinal and transverse positioning hole groups, and chamfered strips are arranged at the ends of the fixed eccentric rods;

[0019] Prefabricated layer pouring, placing the prefabricated components in the pouring inner cavity, through the cooperation of the positioning base and the positioning groove at the lower end of the riser, the prefabricated components are suspended and accurately positioned and installed, and the prefabricated layer is formed by concrete pouring;

[0020] Lifting and disassembly: lift the prefabricated layer after forming through the lifting assembly, disassemble the positioning base and chamfer strip, chamfer the prefabricated layer at the position of the chamfer strip, and form a through embedded hole at the position of the positioning base and the riser;

[0021] During the secondary installation and pouring, a supporting base is placed in the positioning groove to seal the lower end of the embedded hole. During the secondary pouring process, the embedded holes and hollow steel ribs are filled to form a cast-in-place layer. The cast-in-place layer forms a stable staggered pouring connection with the riser and the prefabricated layer by filling the long grooves, embedded holes and open grooves.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention uses longitudinal hollow steel ribs to replace the steel trusses of traditional composite panels, thereby enhancing the rigidity and bearing capacity of the structure, and can prevent the prefabricated bottom plate of the composite panel from cracking during transportation and hoisting; and this structure can reduce the thickness of the prefabricated bottom plate of the composite panel, reduce the dead weight of the prefabricated bottom plate of the composite panel, and make the transportation and hoisting of the composite panel more efficient; during the hoisting construction, less or no lower support can be used, which reduces the construction difficulty and increases the construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the installation structure of the prefabricated hollow steel rib assembly of the present invention;

[0025] Figure 2 This is a schematic diagram of the prefabricated layer casting structure of the present invention;

[0026] Figure 3 It is a schematic diagram of the hoisting and disassembly structure of the present invention;

[0027] Figure 4 This is a schematic diagram of the cast-in-place layer casting structure of the present invention;

[0028] Figure 5 It is a schematic diagram of the three-dimensional structure of the connecting plate of the present invention;

[0029] Figure 6 It is a schematic diagram of the three-dimensional structure of the upper frame of the present invention;

[0030] Figure 7 It is a schematic diagram of the three-dimensional structure of the riser of the present invention;

[0031] Figure 8 for Figure 2 A magnified view of the structure at center;

[0032] Fig. 9 It is a schematic diagram of the three-dimensional structure of the positioning base of the present invention.

[0033] In the figure: 1. casting mold; 2. casting inner cavity; 3. upper frame; 4. connecting plate; 5. lower frame; 6. through long groove; 7. vertical pipe; 8. lower longitudinal beam; 9. lower transverse beam; 10. fixed deflection rod; 11. chamfer strip; 12. positioning groove; 13. positioning base; 14. insertion rod; 15. upper longitudinal beam; 16. upper transverse beam; 17. upper through hole; 18. lower through hole; 19. upper vertical and horizontal positioning hole group; 20. supporting base; 21. prefabricated layer; 22. lifting component; 23. cast-in-place layer; 24. circular ring protrusion; 25. anti-overflow groove; 26. insertion hole; 27. incision; 28. lower vertical and horizontal positioning hole group; 29. ​​opening groove; 30. positioning collar; 31. flexible connecting piece; 32. stud. DETAILED DESCRIPTION

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

[0035] See also Figures 1 to 9 , the present invention provides a technical solution:

[0036] Embodiment 1:

[0037] A concrete composite slab with hollow steel ribs comprises a prefabricated layer 21 and a cast-in-place layer 23.

[0038] A hollow steel rib assembly and a lower steel mesh assembly are arranged in the middle of the prefabricated layer 21. The lower steel mesh assembly is composed of a lower longitudinal beam 8 and a lower transverse beam 9 connected in a crisscross manner. The hollow steel rib assembly is composed of a lower frame 5, an upper frame 3 and a connecting plate 4. The connecting plate 4 is clamped and fixed between the lower frame 5 and the upper frame 3. A vertical pipe 7 is vertically arranged at the connection position of the lower longitudinal beam 8 and the lower transverse beam 9. The lower longitudinal beam 8 penetrates the side wall of the lower frame 5. The outer wall of the vertical pipe 7 is provided with a lower longitudinal and transverse positioning hole group 28 that cooperates with the lower longitudinal beam 8 and the lower transverse beam 9 to penetrate and plug;

[0039] The cast-in-place layer 23 and the prefabricated layer 21 are both cast by concrete. An upper steel mesh assembly is provided in the cast-in-place layer 23. The upper steel mesh assembly is composed of an upper longitudinal beam 15 and an upper transverse beam 16. The upper longitudinal beam 15 is inserted into the upper frame 3. The upper end arc outer wall of the vertical pipe 7 is vertically and horizontally penetrated by an upper longitudinal and transverse positioning hole group 19 that cooperates with the upper longitudinal beam 15 and the upper transverse beam 16.

[0040] By using steel mesh components distributed vertically and horizontally, a reinforced steel skeleton is formed together, so that the cast-in-place layer and the prefabricated layer can be combined into a whole, thereby enhancing the overall stability of the composite slab.

[0041] By using longitudinal hollow steel ribs instead of the steel trusses of traditional composite slabs, the rigidity and bearing capacity of the structure are enhanced, which can prevent the precast base plate of the composite slab from cracking during transportation and hoisting. In addition, this structure can reduce the thickness of the precast base plate of the composite slab, reduce the dead weight of the precast base plate of the composite slab, and make the transportation and hoisting of the composite slab more efficient. During the hoisting construction, less or no lower support can be used, which reduces the construction difficulty and increases the construction efficiency.

[0042] The provision of the riser 7 enables the convenient and accurate positioning and assembly of the steel mesh, and the casting of the riser 7 enhances the longitudinal strength of the composite plate and improves the pressure bearing performance.

[0043] Embodiment 2:

[0044] On the basis of Example 1, in order to improve the convenience and accuracy of pouring the prefabricated layer 21,

[0045] A positioning base 13 is provided at the lower end of the riser 7, and a stud 32 threadedly connected to the lower end port of the riser 7 is provided at the upper end of the positioning base 13. The cast-in-place layer 23 and the prefabricated layer 21 are cast in a casting mold 1, and a casting inner cavity 2 is provided in the casting mold 1. The inner wall of the lower end of the casting inner cavity 2 is provided with a positioning groove 12 that cooperates with the positioning base 13.

[0046] By providing the positioning groove 12 and the positioning base 13, the positioning and installation of the prefabricated component in the casting cavity 2 is achieved, and at the same time, the hollow steel rib component is suspended in the air to facilitate casting and molding.

[0047] Embodiment 3:

[0048] On the basis of Example 2, in order to ensure that the concrete is smoothly poured into the inner cavity of the hollow steel rib assembly during pouring, 45-degree chamfered cuts 27 are provided at both ends of the upper frame 3, and the lower end surface of the upper frame 3 and the upper end surface of the lower frame 5 are provided with linearly distributed plug rods 14, and the upper and lower end surfaces of the connecting plate 4 are provided with plug holes 26, and the plug rods 14 are inserted into the plug holes 26.

[0049] The cutouts 27 are provided so that concrete can enter the interior of the longitudinal hollow steel ribs during pouring, thereby avoiding hollow holes caused by poor concrete fluidity.

[0050] Embodiment 4:

[0051] On the basis of Example 3, in order to realize the positioning and convenient vertical installation of the riser 7, a fixed offset rod 10 is arranged on the outer side wall of the connecting plate 4 and is arranged parallel to the lower longitudinal beam 8, and a positioning ring 30 is arranged on the arc outer wall of the riser 7. The positioning ring 30 is slidably sleeved on the fixed offset rod 10, and a flexible connecting piece 31 is arranged between the positioning ring 30 and the outer wall of the riser 7.

[0052] By providing the cooperation between the fixing part 10 and the positioning collar 30, the vertical installation of the riser 7 is realized, and by providing the flexible connecting piece 31, the installation accuracy of the riser 7 is reduced and the adaptability is improved.

[0053] Embodiment 5:

[0054] The outer edge of the upper end of the prefabricated layer 21 is provided with a chamfer, and the end of the fixed deflection rod 10 is connected with a frame-shaped chamfer strip 11 , and the chamfered inclined surface of the lower end of the chamfer strip 11 fits with the chamfer of the prefabricated layer 21 .

[0055] The casting chamfer is provided on the prefabricated layer 21 by the chamfer strip 11. The chamfer can ensure the thickness of the steel bar protective layer at the connection point on the one hand, and avoid stress concentration at the corner of the cast-in-place concrete on the other hand.

[0056] Embodiment 6:

[0057] On the basis of Example 5, in order to facilitate hoisting and concrete pouring, an upper through hole 17 is provided on the upper frame 3 to cooperate with the upper longitudinal beam 15, and a lower through hole 18 is provided on the side wall of the lower frame 5 to cooperate with the lower longitudinal beam 8. The inner diameter of the lower through hole 18 is smaller than the inner diameter of the upper through hole 17. A pair of through long grooves 6 are provided on the upper frame 3 and the lower frame 5, and the through long grooves 6 on the upper frame 3 are connected to the hoisting assembly 22 of the hoisting equipment.

[0058] The cooperation between the through long groove 6 and the hoisting assembly 22 facilitates the hoisting and disassembly of the auxiliary assembly, and at the same time, the through long groove 6 is used to realize the pouring of the inside of the hollow steel rib.

[0059] Embodiment 7:

[0060] On the basis of Example 6, in order to improve the casting stability of the riser 7, a ring-shaped annular protrusion 24 is further provided on the positioning base 13. The positioning base 13 is disassembled after the prefabricated layer 21 is cast, and the supporting base 20 is placed in the positioning groove 12 after disassembly. The prefabricated layer 21 forms an upwardly concave anti-overflow groove 25 at a position corresponding to the ring protrusion 24, and an open groove 29 is transversely penetrated through the arc outer wall at the upper end of the riser 7. The open groove 29 is located at the upper end of the prefabricated layer 21, and the open groove 29 is located at the lower end of the upper vertical and horizontal positioning hole group 19.

[0061] By setting a circular protrusion 24 on the positioning base 13, a circular anti-overflow groove 25 is formed after pouring. During the secondary pouring, the anti-overflow groove 25 prevents concrete from overflowing outward along the supporting base 20. By setting the opening 29, the staggered pouring between the riser 7 and the cast-in-place layer 23 is achieved, thereby improving the pouring connection strength of the riser 7.

[0062] A construction method for the concrete composite slab with hollow steel ribs, comprising the following steps:

[0063] Prefabricated components are assembled, and the upper frame 3 and the lower frame 5 are assembled through the connecting plate 4 to form a hollow steel rib component. The linearly distributed lower longitudinal beams 8 are inserted into the lower frame 5, and multiple groups of vertical pipes 7 are sleeved along the lower longitudinal beams 8 and the fixed eccentric rods 10. The lower transverse beams 9 are inserted at the positions of the vertical pipes 7 corresponding to the lower longitudinal and transverse positioning hole groups 28, and chamfered strips 11 are provided at the ends of the fixed eccentric rods 10;

[0064] Prefabricated layer casting, placing the prefabricated components in the casting inner cavity 2, through the positioning base 13 at the lower end of the riser 7 and the positioning groove 12, the prefabricated components are suspended and accurately positioned and installed, and the prefabricated layer 21 is formed by concrete casting;

[0065] Lifting and disassembly: lift the prefabricated layer 21 after forming by the lifting assembly 22, disassemble the positioning base 13 and the chamfering strip 11, chamfer the prefabricated layer 21 at the position of the chamfering strip 11, and form a through embedded hole at the position of the positioning base 13 and the riser 7;

[0066] During the secondary installation and pouring, a support base 20 is placed in the positioning groove 12 to block the lower end port of the embedded hole. During the secondary pouring process, the embedded holes and hollow steel ribs are filled to form a cast-in-place layer 23. The cast-in-place layer 23 is filled with the long groove 6, the embedded holes and the open groove 29 to form a stable staggered pouring connection with the riser 7 and the prefabricated layer 21.

[0067] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A concrete composite slab with hollow steel ribs, characterized in that: The concrete composite slab comprises: A prefabricated layer (21), wherein a hollow steel rib assembly and a lower steel mesh assembly are arranged in the middle of the prefabricated layer (21), wherein the lower steel mesh assembly is composed of a lower longitudinal beam (8) and a lower transverse beam (9) connected in a crisscross manner, wherein the hollow steel rib assembly is composed of a lower frame (5), an upper frame (3) and a connecting plate (4), wherein the connecting plate (4) is clamped and fixed between the lower frame (5) and the upper frame (3), wherein a vertical pipe (7) is vertically arranged at a connection position between the lower longitudinal beam (8) and the lower transverse beam (9), wherein the lower longitudinal beam (8) penetrates a side wall of the lower frame (5), and wherein a lower vertical and horizontal positioning hole group (28) is arranged on an outer wall of the vertical pipe (7) and is inserted and penetrated with the lower longitudinal beam (8) and the lower transverse beam (9); A cast-in-place layer (23), wherein the cast-in-place layer (23) and the prefabricated layer (21) are both cast by concrete, and an upper steel mesh assembly is provided in the cast-in-place layer (23), wherein the upper steel mesh assembly is composed of an upper longitudinal beam (15) and an upper transverse beam (16), wherein the upper longitudinal beam (15) is inserted through the upper frame (3), and an upper longitudinal and transverse positioning hole group (19) is provided vertically and horizontally through the arc outer wall of the upper end of the riser (7) and is inserted into and matched with the upper longitudinal beam (15) and the upper transverse beam (16); The lower end of the riser (7) is provided with a positioning base (13), the upper end of the positioning base (13) is provided with a stud (32) threadedly connected to the lower end port of the riser (7), the cast-in-place layer (23) and the prefabricated layer (21) are cast in a casting mold (1), the casting mold (1) is provided with a casting inner cavity (2), and the lower end inner wall of the casting inner cavity (2) is provided with a positioning groove (12) that is sleeved with the positioning base (13); Both ends of the upper frame (3) are provided with 45-degree chamfered cutouts (27); the lower end surface of the upper frame (3) and the upper end surface of the lower frame (5) are both provided with linearly distributed plug rods (14); the upper and lower end surfaces of the connecting plate (4) are provided with plug holes (26); the plug rods (14) are plugged into the plug holes (26); The outer side wall of the connecting plate (4) is provided with a fixed bias rod (10) which is arranged in parallel and offset with the lower longitudinal beam (8), and the arc outer wall of the vertical pipe (7) is provided with a positioning collar (30), the positioning collar (30) is slidably sleeved on the fixed bias rod (10), and a flexible connecting piece (31) is provided between the positioning collar (30) and the outer wall of the vertical pipe (7).

2. The concrete composite slab with hollow steel ribs according to claim 1, characterized in that: The outer edge of the upper end of the prefabricated layer (21) is provided with a chamfer, and the end of the fixed deflection rod (10) is connected to a frame-shaped chamfer strip (11), and the chamfered inclined surface at the lower end of the chamfer strip (11) fits with the chamfer of the prefabricated layer (21).

3. The concrete composite slab with hollow steel ribs according to claim 2, characterized in that: The upper frame (3) is provided with an upper through hole (17) for plugging with the upper longitudinal beam (15), and the side wall of the lower frame (5) is provided with a lower through hole (18) for plugging with the lower longitudinal beam (8), wherein the inner diameter of the lower through hole (18) is smaller than the inner diameter of the upper through hole (17).

4. The concrete composite slab with hollow steel ribs according to claim 3, characterized in that: A pair of through-going long grooves (6) are provided on both the upper frame (3) and the lower frame (5), and the through-going long grooves (6) on the upper frame (3) are connected to the hoisting components (22) of the hoisting equipment.

5. The concrete composite slab with hollow steel ribs according to claim 4, characterized in that: The positioning base (13) is provided with a circular annular protrusion (24); the positioning base (13) is disassembled after the prefabricated layer (21) is cast; after disassembly, a support base (20) is placed in the positioning groove (12); and the prefabricated layer (21) forms an upwardly concave anti-overflow groove (25) at a position corresponding to the circular annular protrusion (24).

6. The concrete composite slab with hollow steel ribs according to claim 5, characterized in that: An open groove (29) is provided transversely through the arc outer wall at the upper end of the riser (7), the open groove (29) is located at the upper end of the prefabricated layer (21), and the open groove (29) is located at the lower end of the upper vertical and horizontal positioning hole group (19).

7. A construction method for the concrete composite slab with hollow steel ribs according to claim 6, characterized in that: The construction method comprises the following steps: Assembling the prefabricated components, assembling the upper frame (3) and the lower frame (5) through the connecting plate (4) to form a hollow steel rib component, inserting linearly distributed lower longitudinal beams (8) into the lower frame (5), sleeve-connecting multiple groups of vertical pipes (7) along the lower longitudinal beams (8) and the fixed eccentric rods (10), inserting the lower transverse beams (9) at the positions of the vertical pipes (7) corresponding to the lower longitudinal and transverse positioning hole groups (28), and providing chamfer strips (11) at the ends of the fixed eccentric rods (10); Prefabricated layer casting, placing the prefabricated components in the casting inner cavity (2), achieving the suspension and precise positioning installation of the prefabricated components through the cooperation of the positioning base (13) at the lower end of the vertical pipe (7) and the positioning groove (12), and forming the prefabricated layer (21) by concrete casting; Lifting and disassembling, lifting the prefabricated layer (21) after forming by means of a lifting assembly (22), disassembling the positioning base (13) and the chamfering strip (11), forming a chamfer on the prefabricated layer (21) at the position of the chamfering strip (11), and forming a through embedded hole at the position of the positioning base (13) and the riser (7); During the secondary installation and pouring, a support base (20) is placed in the positioning groove (12) to block the lower end of the embedded hole. During the secondary pouring process, the embedded hole and the hollow steel rib are filled to form a cast-in-place layer (23). The cast-in-place layer (23) is filled with the embedded hole and the open groove (29) to form a stable offset pouring connection with the riser (7) and the prefabricated layer (21).

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