Prefabricated column and cast-in-place flat slab inner ring beam combined structure

Abstract

The utility model discloses a prefabricated column and cast-in-place flat slab inner ring beam combined structure which comprises a bottom plate structure, a prefabricated column structure, a cast-in-place flat slab, a cast-in-place joint reinforcing inner ring beam and a formwork supporting system. Comprising a foundation area and a central thickening area, the central thickening area is arranged around a prefabricated column structure, a cast-in-place joint reinforcing inner ring beam is arranged on the side, close to the prefabricated column structure, in the central thickening area, and shear-resistant key grooves are formed in the outer walls of joint layering positions of the prefabricated column structure; the inner side of the central thickening area of the cast-in-place flat slab is connected with the anti-shear key groove in an engaged mode. The inner ring beam is arranged on the floor, so that concrete of the ring beam part is gathered inwards towards the prefabricated column, the integrity of the floor part is enhanced, meanwhile, the shear resistance is enhanced in cooperation with the shear-resistant key groove, throwing ribs do not need to be arranged between the prefabricated column and the floor for connection, and the construction efficiency is extremely high.

Description

Technical Field

[0001] The utility model belongs to the field of combining assembled components with cast-in-situ components, in particular to a combined structure of prefabricated columns and inner ring beams of cast-in-situ beamless floor slabs. Background Art

[0002] Prefabricated columns are commonly used prefabricated components. The nodes used to connect prefabricated columns are important component connection nodes of prefabricated structures and have always been a difficult problem to solve in prefabricated frame structures.

[0003] Currently, when precast columns are connected to cast-in-place horizontal components, they need to be connected with reinforcement bars between the components. Without this, the shear strength between the floor slab and the precast columns cannot be guaranteed. When applied to a cast-in-place system for beamless floors, referring to existing processes, the end reinforcement bars of the floor slab need to be inserted into the horizontal holes reserved on the column and pass through the column, or the floor slab reinforcement bars need to be embedded in the nodes of the precast columns and tied to the embedded steel bars of the floor slab. Both of these methods require very high performance in the steel bar installation process at this location, and the installation will take a lot of time during construction.

[0004] If the shear strength is to be guaranteed without performing the reinforcement construction, the reinforcement density needs to be increased at this position, which makes the reinforcement binding at the core area of ​​the column extremely complicated and the construction efficiency is extremely low.

[0005] At the same time, the bottom node of the prefabricated hollow column is generally connected to the foundation structure with a grouting sleeve, which has high requirements for grouting materials and construction and installation. It is often difficult to grout densely during the construction process, and the detection means are relatively simple, making it difficult to ensure construction quality. Utility Model Content

[0006] The purpose of the utility model is to provide a combined structure of prefabricated columns and inner ring beams of cast-in-place beamless floor slabs, and to solve the technical problem that when the existing prefabricated columns are applied to the beamless floor slab structural system, the reinforcement construction at this position has very high requirements on the performance of the reinforcement installation process, and a lot of time is spent on positioning installation during construction. At the same time, the shear resistance measure adopts the method of reinforcing steel bars to make the reinforcement binding at the core area of ​​the column extremely complicated, resulting in extremely low construction efficiency. It is also necessary to solve the technical problem that the bottom of the prefabricated hollow column is connected by a grouting sleeve, which has high requirements on grouting material and construction and installation, and the construction process is often difficult to grout densely, the detection means are also relatively simple, and it is difficult to ensure the construction quality.

[0007] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A combined structure of precast columns and cast-in-place beamless floor inner ring beams, comprising a base plate structure, a precast column structure, a cast-in-place beamless floor, a cast-in-place node reinforced inner ring beam and a formwork support system.

[0009] The bottom of the precast column structure is fixedly connected to the top surface of the base plate structure through a mortar layer. The bottom of the formwork support system stands on the top surface of the base plate structure, and the top of the formwork support system is supported on the bottom of the cast-in-place beamless floor.

[0010] The precast column structure is a single-section multi-layer precast column, and the cast-in-place beamless floor is set at the node layer position of the precast column structure.

[0011] The cast-in-place beamless floor is a variable-section floor, including a foundation area and a central thickening area. The central thickening area is set around the prefabricated column structure.

[0012] The cast-in-place node reinforced inner ring beam is arranged in the central thickening area, close to the side of the prefabricated column structure. The outer wall of the node layered position of the prefabricated column structure is provided with a shear key groove, and the inner side of the central thickening area of ​​the cast-in-place beamless floor is engaged with the shear key groove.

[0013] The bottom surface of the central thickened area transitions to the bottom surface of the base area through a bevel, and the top surface of the central thickened area is flush with the top surface of the base area.

[0014] The steel bars in the central thickening area include transverse bars in the thickening area. The transverse bars in the thickening area are U-shaped bars. The transverse bars in the thickening area include bottom side limbs, inner limbs close to the prefabricated column structure and outer limbs close to the foundation area. The top of the inner limb is bent outward to form a hook section, and the outer limb is inclined from the edge of the central thickening area to the foundation area, and the inclination angle is adapted to the slope of the hypotenuse.

[0015] The top end of the outer limb is bent outward to form a horizontal connecting section. The elevation of the horizontal connecting section is the same as that of the hook section. The horizontal connecting section is fixedly connected to the steel bars of the foundation area, connecting the foundation area and the central thickening area into one.

[0016] The steel bars in the central thickening area also include the thickening area longitudinal bars, which include the thickening bottom longitudinal bars, the thickening inner longitudinal bars and the thickening outer longitudinal bars. The thickening bottom longitudinal bars are arranged in a row along the upper side of the bottom side limb of the central thickening area, the thickening inner longitudinal bars are arranged in the hook section, and the thickening outer longitudinal bars are arranged on the inner side of the outer limb.

[0017] The steel bars in the central thickening area are integrally formed into a steel bar installation groove for reinforcing the inner ring beam of the cast-in-situ node. The steel bars for reinforcing the inner ring beam of the cast-in-situ node include ring beam longitudinal bars and ring beam stirrups. The ring beam stirrups are connected to the outer periphery of the ring beam longitudinal bars. The ring beam longitudinal bars include ring beam bottom bars and ring beam top bars. The ring beam stirrups include stacked stirrups arranged in multiple layers. The heights of the stacked stirrups are the same, and the widths of the stacked stirrups gradually increase. The number of ring beam longitudinal bars connected by the stacked stirrups increases layer by layer, and the difference in the number of ring beam longitudinal bars connected by adjacent stacked stirrups is an arithmetic progression.

[0018] The top elevation of the ring beam stirrups is the same as the top elevation of the transverse reinforcement in the thickened area, and the bottom surface of the ring beam stirrups is located on the upper side of the thickened bottom longitudinal reinforcement.

[0019] The shear keyway is wavy and has a trapezoidal cross section.

[0020] The formwork support system includes wooden planks, vertical poles, horizontal poles, diagonal poles and panels, which are divided into foundation area support and central thickening area support according to the support areas. The panels are set obliquely at the transition position between the two areas. Encrypted vertical poles are installed between the foundation area support and the central thickening area support. The encrypted vertical poles are connected to the vertical poles of the foundation area support and the central thickening area support through encrypted horizontal poles.

[0021] The prefabricated column structure is a hollow prefabricated column, including a column wall plate and a central cavity. The shear key groove is set on the surface of the column wall plate. The central cavity is poured with self-compacting concrete and connected to the mortar layer.

[0022] The combined structure of precast columns and inner ring beams of cast-in-place beamless floor slabs also includes a shear connection structure at the column bottom. The bottom plate structure is thickened at the position corresponding to the precast column structure to form a shear floor. The shear connection structure at the column bottom includes a shear steel cage. The shear steel cage includes shear longitudinal bars and shear stirrups. The bottom of the shear longitudinal bars is buried in the shear floor, and the shear stirrups are all located in the central cavity.

[0023] Compared with the prior art, the present invention has the following characteristics and beneficial effects:

[0024] The utility model provides a shear key groove on the column wall of the precast column, and the concrete of the cast-in-place floor engages with the shear key groove after being poured; at the same time, the structure of the cast-in-place floor is designed to have a variable cross-section, a central thickening area is provided near the precast column, and a node-reinforced inner ring beam is provided in the central thickening area. The stirrups of the node-reinforced inner ring beam are designed to be multiple overlapping stirrups, so that the concrete of the ring beam part is gathered inward toward the precast column, thereby enhancing the integrity of this part of the floor, and at the same time, cooperating with the shear key groove to enhance the shear resistance.

[0025] During the construction process of the utility model, there is no need to set up reinforcement connections between the prefabricated columns and the floor. During construction, it is only necessary to design the cross-section of the cast-in-place floor, and the transverse reinforcement and the longitudinal reinforcement in the thickened area are designed to be a U-shaped steel mesh to form an installation groove for the node-reinforced inner ring beam. Then, the steel cage of the node-reinforced inner ring beam is installed as a whole on the central thickened area, and then the floor concrete and the ring beam concrete are cast in one piece to form a floor structure connected to the prefabricated columns. There is no need for complicated steel bar binding and steel bar alignment installation, and the construction efficiency is extremely high.

[0026] When the utility model adopts prefabricated hollow columns, the seat mortar layer is connected with the bottom plate structure, and a shear-resistant steel cage is arranged between the bottom plate structure and the central cavity to enhance the shear resistance of the column base.

[0027] The formwork support system of the present invention can be supported according to the central thickening area and the foundation area, and additional encrypted supports can be provided between the two areas to ensure the stability of the support system and the casting quality of the cast-in-place beamless floor. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described in detail below with reference to the accompanying drawings.

[0029] Figure 1 It is a side structural schematic diagram of the utility model.

[0030] Figure 2 The utility model is a schematic diagram of the steel structure of the cast-in-situ beamless floor and the cast-in-situ node reinforced inner ring beam.

[0031] Figure 3 yes Figure 2 Schematic diagram of the structure after pouring concrete of the cast-in-place beamless floor and cast-in-place node reinforced inner ring beam.

[0032] Figure 4 It is a schematic diagram of the shear-resistant structure of the column base of the utility model.

[0033] Figure 5 It is a schematic diagram of the planar structure of the cast-in-situ node reinforced inner ring beam of the utility model.

[0034] Figure 6 It is a schematic diagram of the cross-sectional structure of the cast-in-situ node reinforced inner ring beam of the utility model.

[0035] Figure 7 It is a side structural schematic diagram of the cast-in-situ node reinforced inner ring beam of the utility model.

[0036] Figure numbers: 1-base plate structure, 11-shear floor, 2-precast column structure, 21-shear keyway, 22-column wall plate, 23-central cavity, 24-self-compacting concrete, 3-cast-in-situ beamless floor, 31-foundation area, 32-central thickening area, 321-bottom side limb, 322-inner limb, 323-outer limb, 324-hook section, 325-horizontal tension section, 326-thickened bottom longitudinal reinforcement, 327-thickened inner longitudinal reinforcement, 328-thickened outer longitudinal reinforcement, 33-bevel, 4-cast-in-situ node reinforcement inner ring Beam, 41-ring beam longitudinal reinforcement, 411-ring beam bottom reinforcement, 412-ring beam top reinforcement, 42-composite stirrups, 421-small stirrups, 422-medium stirrups, 423-large stirrups, 5-formwork support system, 51-bidirectional keel, 52-vertical pole, 53-horizontal pole, 54-diagonal pole, 55-panel, 5a-foundation area support, 5b-central thickening area support, 56-densified vertical pole, 57-densified horizontal pole, 6-mortar layer, 7-shear steel cage, 71-shear longitudinal reinforcement, 72-shear stirrups. DETAILED DESCRIPTION

[0037] For example, see Figure 1-7As shown, a precast column and cast-in-situ beamless floor inner ring beam combination structure includes a base plate structure 1, a precast column structure 2, a cast-in-situ beamless floor 3, a cast-in-situ node reinforced inner ring beam 4 and a formwork support system 5. The precast column structure 2 is a hollow precast column.

[0038] See also Figure 4 As shown, the bottom of the precast column structure 2 is fixedly connected to the top surface of the base plate structure 1 via a mortar layer 6. When the precast column structure 2 is a hollow precast column, the combined structure of the precast column and the inner ring beam of the cast-in-place beamless floor further includes a column bottom shear connection structure. The base plate structure 1 is thickened at a position corresponding to the precast column structure 2 to form a shear floor 11. The column bottom shear connection structure includes a shear steel cage 7. The shear steel cage 7 includes shear longitudinal bars 71 and shear stirrups 72. The bottom of the shear longitudinal bars 71 is embedded in the shear floor 11, and the shear stirrups 72 are all located in the central cavity 23.

[0039] The prefabricated column structure 2 is a single-section multi-layer prefabricated column. The cast-in-place beamless floor 3 is arranged at the node layered position of the prefabricated column structure 2, including a column wall plate 22 and a central cavity 23. The shear key groove 21 is arranged on the surface of the column wall plate 22, and the self-compacting concrete 24 is poured in the central cavity 23 and connected to the mortar layer 6.

[0040] The cast-in-place beamless floor 3 is a variable-section floor, including a foundation area 31 and a central thickened area 32 . The central thickened area 32 is arranged around the prefabricated column structure 2 .

[0041] The cast-in-place node reinforcement inner ring beam 4 is located within the central thickened area 32, near the precast column structure 2. Shear key slots 21 are provided on the outer wall of the precast column structure 2 at the node layer. The inner side of the central thickened area 32 of the cast-in-place flat floor 3 engages with the shear key slots 21. The shear key slots 21 are wavy and have a trapezoidal cross-section.

[0042] The bottom surface of the central thickened area 32 transitions to the bottom surface of the base area 31 via a bevel 33 , and the top surface of the central thickened area 32 is flush with the top surface of the base area 31 .

[0043] The steel bars of the central thickening area 32 include transverse bars in the thickening area, which are U-shaped bars. The transverse bars in the thickening area include bottom side limbs 321, inner limbs 322 close to the prefabricated column structure 2, and outer limbs 323 close to the foundation area 31. The top of the inner limb 322 is bent outward to form a hook section 324, and the outer limb 323 is inclined from the edge of the central thickening area 32 to the foundation area 31, and the inclination angle is adapted to the slope of the hypotenuse 33.

[0044] The top end of the outer limb 323 is bent outward to form a horizontal pulling section 325. The elevation of the horizontal pulling section 325 is the same as the elevation of the hook section 324. The horizontal pulling section 325 is fixedly connected to the steel bars of the foundation area 31, pulling the foundation area 31 and the central thickening area 32 into one.

[0045] The steel bars of the central thickened area 32 also include thickened area longitudinal bars, which include thickened bottom longitudinal bars 326, thickened inner longitudinal bars 327 and thickened outer longitudinal bars 328. The thickened bottom longitudinal bars 326 are arranged in a row along the upper side of the bottom side limb 321 of the central thickened area 32, the thickened inner longitudinal bars 327 are arranged in the hook section 324, and the thickened outer longitudinal bars 328 are arranged on the inner side of the outer limb 323.

[0046] The steel bars of the central thickened area 32 form as a whole a steel bar installation groove for the cast-in-situ node reinforced inner ring beam 4. The steel bars of the cast-in-situ node reinforced inner ring beam 4 include ring beam longitudinal bars 41 and ring beam stirrups. The ring beam stirrups are connected to the outer periphery of the ring beam longitudinal bars 41. The ring beam longitudinal bars 41 include ring beam bottom bars 411 and ring beam top bars 412. The ring beam stirrups include stacked stirrups 42 arranged in multiple layers. The height of the stacked stirrups 42 is the same, and the width of the stacked stirrups 42 gradually increases. The number of ring beam longitudinal bars 41 connected by the stacked stirrups 42 increases layer by layer, and the difference in the number of ring beam longitudinal bars 41 connected by adjacent stacked stirrups 42 is an arithmetic progression.

[0047] See also Figure 5-7 As shown, in this embodiment, the laminated stirrups 42 are composed of three layers, including small stirrups 421, medium stirrups 422, and large stirrups 423. The top elevation of the ring beam stirrups is the same as the top elevation of the thickened transverse reinforcement, and the bottom surface of the ring beam stirrups is located above the thickened bottom longitudinal reinforcement 326.

[0048] See also Figure 1 As shown, the bottom of the formwork support system 5 stands on the top surface of the base plate structure 1, and the top of the formwork support system 5 is supported on the bottom of the cast-in-place beamless floor 3. The formwork support system 5 includes a bidirectional keel 51, vertical rods 52, horizontal rods 53, diagonal rods 54 and panels 55. According to the support area, it is divided into the foundation area support 5a and the central thickening area support 5b. The panel 55 is arranged diagonally at the transition position between the two areas. A dense vertical rod 56 is arranged between the foundation area support 5a and the central thickening area support 5b. The dense vertical rod 56 is connected to the vertical rods 52 of the foundation area support 5a and the central thickening area support 5b through a dense horizontal rod 57. The bidirectional keel 51 is set on the top of the vertical rod 52 and supported on the bottom of the panel 55. The bottom of the vertical rod 52 stands on the top surface of the base plate structure 1. The horizontal rod 53 is connected between the vertical rods 52. The vertical rods 52 and the horizontal rods 53 enclose a support frame. The diagonal rods 54 are connected to the diagonal position of the support frame.

[0049] The construction method of this prefabricated column and cast-in-place beamless floor inner ring beam combination structure has the following construction steps:

[0050] Step 1: Design the dimensions of the cast-in-situ beamless floor 3 and the cast-in-situ node reinforcement inner ring beam 4 according to the dimensions of the precast column structure 2, and design the support layout dimensions of the formwork support system 5;

[0051] Step 3: Determine the position of the precast column structure 2 on the surface of the base plate structure 1 and measure and lay out the lines. After cleaning the surface of the base plate structure 1, a professional surveyor will lay out the axis and the control lines of the precast column structure 2 according to the drawings and mark them.

[0052] Step 4: Use the self-made steel bar positioning control steel hoop to review and correct the shear steel cage 7 extending from the bottom plate structure 1; check whether the reserved steel bar position, verticality, and reserved steel bar length are accurate. If the steel bar positioning error and steel bar spacing error are within the range of ±5mm, it is qualified; correct the steel bars that do not meet the requirements, and adjust the deviated steel bars in time.

[0053] Step five: water the mortar base of the prefabricated column structure 2, and use the mortar to mortar the entire bottom of the column. The height of the mortar layer 6 is 1 cm higher than the joint height, and it is trimmed with a trowel, high in the middle and low around. The low point is not lower than the joint height. If it is found that there is a part on the edge of the component where the mortar has not overflowed during the verticality adjustment process, lift it immediately, add mortar to the missing part, and re-trim the slope.

[0054] Step 6: Place a rubber tire or two layers of 10mm x 10mm wooden planks at the base of precast column structure 2, and pad the top with soft gaskets. At the same time, tie a traction rope approximately 1m from the base of the column. If precast column structure 2 wobbles after flipping, pull the traction rope to maintain balance. Then, use the tower crane to flip it over and lift it using the prefabricated lifting rings. Before lifting, the quality manager will verify the number and dimensions of precast column structure 2. Once the quality is verified, a dedicated person will be responsible for hooking the precast column structure. Once the hooking personnel have evacuated to a safe area, the signalman below will confirm the safety of the component and direct the lifting to proceed slowly. When the precast column structure is approximately 500mm above the ground, the tower crane will confirm that it is safe and continue lifting. Once the precast column structure is lowered to 500mm from the foundation structure, fine-tune it according to the pre-determined control lines. Once fine-tuning is complete, the lowering process will be slowed down. Two professional operators will manually guide the lowering process. When the column structure is about 100mm below the foundation, one worker will use a plumb line to check that the column edge is aligned with the horizontal positioning line. After the prefabricated column structure 2 is in place, a level is used to check the elevation. Each column must be checked after it is hoisted.

[0055] Step 7: Set up the formwork support system: First, place the vertical poles 52 according to the support plane layout plan, with four poles forming a basic assembly unit. Then, simultaneously install the horizontal poles 53 and diagonal poles 54, and tighten the upper buckles to secure the nodes. Using this basic unit as a starting point, install the other support frame unit poles, adjusting and reinforcing them as they are installed. Finally, install the upper adjustable brace, completing the entire frame. Finally, install the bidirectional keel 51, and then lay the panel 55 on top of the bidirectional keel 51. Note that the support heights of the foundation area support 5a and the central thickening area support 5b are different. Install dense vertical poles 56 and dense horizontal poles 57 between the two areas.

[0056] Step eight, tie the steel bars of the cast-in-place beamless floor 3, and then hoist the finished steel cage of the cast-in-place node reinforcement inner ring beam. Pay attention to slow lifting and lowering. After the finished steel cage is hoisted to the top of the prefabricated column structure 2, pull the traction rope to fine-tune the position of the finished steel cage so that the center of the finished steel cage is aligned with the prefabricated column structure 2 to avoid collision and corner loss of the two components. After the fine-tuning is completed, slow down the lowering until it falls on the formwork pad, and check the elevation and levelness in time.

[0057] Step nine, integrally pouring the concrete of the cast-in-place beamless floor and the cast-in-place node reinforced inner ring beam. When the precast column structure 2 is a hollow precast column, pour self-compacting concrete 11 in the central cavity 24, and use the characteristics of the self-compacting concrete 11 and the kinetic energy generated by the fall to achieve a certain density of the concrete.

Claims

1. A combined structure of precast columns and inner ring beams of cast-in-place beamless floor slabs, characterized by: It includes a base plate structure (1), a prefabricated column structure (2), a cast-in-situ beamless floor (3), a cast-in-situ node reinforced inner ring beam (4) and a formwork support system (5). The bottom of the prefabricated column structure (2) is fixedly connected to the top surface of the base plate structure (1) through a mortar layer (6), the bottom of the formwork support system (5) is erected on the top surface of the base plate structure (1), and the top of the formwork support system (5) is supported on the bottom of the cast-in-place beamless floor (3). The precast column structure (2) is a single-section multi-layer precast column, and the cast-in-place beamless floor (3) is arranged at the node layer position of the precast column structure (2). The cast-in-place beamless floor (3) is a variable-section floor, comprising a foundation area (31) and a central thickening area (32). The central thickening area (32) is arranged around the prefabricated column structure (2). The cast-in-situ node reinforcement inner ring beam (4) is arranged in the central thickening area (32) and on one side close to the prefabricated column structure (2); the outer wall of the node layer position of the prefabricated column structure (2) is provided with a shear key groove (21); and the inner side of the central thickening area (32) of the cast-in-situ beamless floor (3) is engaged with the shear key groove (21).

2. The combined structure of prefabricated columns and inner ring beams of cast-in-place beamless floor according to claim 1 is characterized in that: The bottom surface of the central thickened area (32) and the bottom surface of the base area (31) are transitioned through the bevel (33), and the top surface of the central thickened area (32) is flush with the top surface of the base area (31).

3. The combined structure of precast columns and inner ring beams of cast-in-place beamless floor according to claim 2 is characterized in that: The reinforcement of the central thickening area (32) includes a thickening area transverse reinforcement, which is a U-shaped reinforcement. The thickening area transverse reinforcement includes a bottom side limb (321), an inner limb (322) close to the prefabricated column structure (2), and an outer limb (323) close to the foundation area (31). The top of the inner limb (322) is bent outward to form a hook section (324), and the outer limb (323) is inclined from the edge of the central thickening area (32) to the foundation area (31), and the inclination angle is adapted to the slope of the hypotenuse (33).

4. The combined structure of precast columns and inner ring beams of cast-in-place beamless floor according to claim 3 is characterized in that: The top end of the outer limb (323) is bent outward to form a horizontal pull-connecting section (325). The elevation of the horizontal pull-connecting section (325) is the same as the elevation of the hook section (324). The horizontal pull-connecting section (325) is fixedly connected to the steel bars of the foundation area (31) and pulls the foundation area (31) and the central thickening area (32) into one.

5. The combined structure of prefabricated columns and inner ring beams of cast-in-place beamless floor according to claim 4 is characterized in that: The reinforcement of the central thickened area (32) further includes thickened area longitudinal reinforcement, which includes thickened bottom longitudinal reinforcement (326), thickened inner longitudinal reinforcement (327) and thickened outer longitudinal reinforcement (328), wherein the thickened bottom longitudinal reinforcement (326) is provided in a row along the upper side of the bottom limb (321) of the central thickened area (32), the thickened inner longitudinal reinforcement (327) is provided in the hook section (324), and the thickened outer longitudinal reinforcement (328) is provided on the inner side of the outer limb (323).

6. The combined structure of precast columns and inner ring beams of cast-in-place beamless floor according to claim 5 is characterized in that: The steel bars of the central thickened area (32) are integrally formed into a steel bar installation groove for the cast-in-situ node reinforced inner ring beam (4). The steel bars of the cast-in-situ node reinforced inner ring beam (4) include ring beam longitudinal bars (41) and ring beam stirrups. The ring beam stirrups are connected to the outer periphery of the ring beam longitudinal bars (41). The ring beam longitudinal bars (41) include ring beam bottom bars (411) and ring beam top bars (412). The ring beam stirrups include stacked stacked stirrups (42) arranged in multiple layers. The stacked stirrups (42) have the same height, and the width of the stacked stirrups (42) gradually increases. The stacked stirrups (42) connect to the ring beam longitudinal bars (41) and the number of stacked ring beam longitudinal bars (41) increases layer by layer. The difference in the number of stacked ring beam longitudinal bars (41) connected to adjacent stacked stirrups (42) is an arithmetic progression.

7. The combined structure of precast columns and inner ring beams of cast-in-place beamless floor according to claim 6 is characterized in that: The top elevation of the ring beam stirrups is the same as the top elevation of the transverse reinforcement in the thickened area, and the bottom surface of the ring beam stirrups is located on the upper side of the thickened bottom longitudinal reinforcement (326).

8. The precast column and cast-in-place beamless floor inner ring beam combined structure according to claim 1 is characterized in that: The shear key groove (21) is wavy and has a trapezoidal cross section.

9. The precast column and cast-in-situ beamless floor inner ring beam combined structure according to claim 1, characterized in that: The formwork support system (5) includes a bidirectional keel (51), a vertical rod (52), a horizontal rod (53), an oblique rod (54) and a panel (55), which is divided into a base area support (5a) and a central thickening area support (5b) according to the support area. The panel (55) is obliquely arranged at the transition position between the two areas. An encrypted vertical rod (56) is provided between the base area support (5a) and the central thickening area support (5b). The encrypted vertical rod (56) is connected to the vertical rods (52) of the base area support (5a) and the central thickening area support (5b) through an encrypted horizontal rod (57).

10. The precast column and cast-in-situ beamless floor inner ring beam combined structure according to claim 1, characterized in that: The prefabricated column structure (2) is a hollow prefabricated column, comprising a column wall plate (22) and a central cavity (23). A shear key groove (21) is provided on the surface of the column wall plate (22). Self-compacting concrete (24) is poured into the central cavity (23) and connected to the mortar layer (6). The combined structure of precast columns and cast-in-place beamless floor inner ring beams also includes a column bottom shear connection structure, wherein the bottom plate structure (1) is thickened at a position corresponding to the precast column structure (2) to form a shear floor (11), and the column bottom shear connection structure includes a shear steel cage (7), the shear steel cage (7) includes shear longitudinal bars (71) and shear stirrups (72), the bottom of the shear longitudinal bars (71) is embedded in the shear floor (11), and the shear stirrups (72) are all located in the central cavity (23).

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