Prefabricated multi-layer bracket column

Abstract

The utility model discloses a prefabricated multilayer bracket column, including column body, bracket, pre -buried dry -type connecting system and beam column node area column core structure, the column body is factory prefabricated reinforced concrete component, and its length spans at least two standard floors, and the column body is factory prefabricated reinforced concrete component that spans at least two standard floors, compared with the design of present one layer one column needing layer -by -layer splicing, directly reduces column -column connecting node, when spanning two layers, only needs a column -column node to replace traditional two, simultaneously, the column core of beam column node area adopts steel pipe -UHPC combination, and the restraint of steel pipe is combined with the high strength, high toughness of super -high performance concrete, makes the node core area form the rigid core of excellent mechanical property, effectively avoids the ductility of the existing large number of splicing nodes, the reliability hidden danger problem of insufficient, more easily satisfies the seismic design principle of strong column -strong node -weak beam, significantly promotes building overall seismic capacity and structural safety redundancy.

Description

Technical Field

[0001] This utility model relates to the field of prefabricated concrete structure building technology, specifically a prefabricated multi-layer corbel column. Background Technology

[0002] Currently, the mainstream application of prefabricated frame structures in the construction field adopts the "one column per floor" prefabricated column design, that is, each floor of the building corresponds to an independent prefabricated column, and the prefabricated columns of adjacent floors need to be spliced ​​together by welding steel plates and grouting near the floor level; at the same time, the connection between prefabricated beams and prefabricated columns also needs to be achieved by additionally laying out connectors or pouring nodes on site, making the overall connection process complex.

[0003] The existing "one column per floor" structure and connection method have the following core technical problems:

[0004] With a large number of nodes, there are potential risks to the structural reliability. Each floor of the building needs to be equipped with one column-to-column connection node and one beam-to-column connection node, which causes the number of connection nodes in the building to increase exponentially with the number of floors. Especially in seismic design scenarios, it is difficult to uniformly guarantee the mechanical reliability and ductility of a large number of nodes, which can easily become weak links in the seismic resistance of the structure and pose a potential risk to the overall safety of the building. Therefore, we need to propose a precast multi-story corbel column. Utility Model Content

[0005] The purpose of this utility model is to provide a prefabricated multi-story corbel column. By setting a factory-prefabricated reinforced concrete column body that spans at least two standard floors, and using a steel pipe-UHPC composite for the column core in the beam-column joint area, it achieves the effects of reducing the number of column-column connection nodes, avoiding the insufficient ductility and reliability risks caused by the large number of spliced ​​nodes, and meeting the seismic design principle of "strong column-strong node-weak beam". This significantly improves the overall seismic resistance and structural safety redundancy of the building, thereby solving the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A precast multi-story corbel column includes: a column body, corbels, a pre-embedded dry connection system, and a column core structure in the beam-column joint area; the column body is a factory-precast reinforced concrete component, the length of which spans at least two standard floors; at the design position of the column body corresponding to the bottom elevation of the beam on each floor, the corbel is integrally formed with an outwardly protruding part; the corbel is internally configured with dense diagonal reinforcing bars and stirrups; the pre-embedded dry connection system includes a lower connector pre-embedded on the top surface of the corbel and a matching upper connector pre-embedded at the end of the precast beam; the column core structure in the beam-column joint area is a steel pipe pre-embedded at the column core position in the beam-column joint area, the steel pipe being filled with ultra-high performance concrete to form a steel pipe-UHPC composite.

[0008] Preferably, one end of the inclined reinforcing bar is anchored in the core area of ​​the column, and the other end extends to the bearing plate at the outer edge of the corbel.

[0009] Preferably, the bearing plate is fixedly connected to the extension end of the inclined reinforcing steel bar to transfer the beam end load of the precast beam.

[0010] Preferably, the top surface of the corbel is a horizontal bearing surface, and a pre-embedded steel plate is embedded in the horizontal bearing surface. The pre-embedded steel plate is configured to cooperate with the lower connecting component of the pre-embedded dry connection system.

[0011] Preferably, the upper connector of the pre-embedded dry connection system is a connecting steel plate pre-embedded at the end of the precast beam, and the position of the connecting steel plate corresponds precisely to the position of the lower connector.

[0012] Preferably, the upper connector and the lower connector are rigidly connected by on-site welding to transfer the bending moment and shear force at the beam end.

[0013] Preferably, the precast beam ends are pre-embedded with steel bar mechanical sleeves, and short steel bars are provided on site.

[0014] Preferably, one end of the short reinforcing bar is connected to the reinforcing bar mechanical sleeve, and the other end extends into the post-cast area of ​​the node.

[0015] Preferably, the column spans 2-4 standard floors, and the corbel dimensions for each floor are designed based on the beam load parameters of that floor.

[0016] Preferably, the corbel and column body are formed by one-time casting in the factory.

[0017] Compared with the prior art, the beneficial effects of this utility model are:

[0018] The column of this utility model is a factory-prefabricated reinforced concrete component spanning at least two standard floors. Compared with the existing design of one column per floor that requires splicing layer by layer, it directly reduces the number of column-to-column connection nodes (e.g., when spanning two floors, only one column-to-column node is needed instead of the traditional two). At the same time, the column core in the beam-column joint area adopts a steel pipe-UHPC composite. The restraining effect of the steel pipe combined with the high strength and high toughness of ultra-high performance concrete (UHPC) makes the core area of ​​the joint form a rigid core with excellent mechanical properties. This effectively avoids the problems of insufficient ductility and reliability hazards caused by a large number of spliced ​​nodes in the existing design. It is easier to meet the seismic design principle of strong column-strong node-weak beam, and significantly improves the overall seismic resistance and structural safety redundancy of the building. Attached Figure Description

[0019] Figure 1 This is a front axonometric view of the prefabricated multi-layer corbel column of this utility model;

[0020] Figure 2 This is a structural schematic diagram of the front axonometric view of the prefabricated corbel column of this utility model;

[0021] Figure 3 This is a structural schematic diagram of the inclined reinforcing bars, stirrups, and embedded steel plates of this utility model;

[0022] Figure 4 This is a structural schematic diagram of the front axonometric view of the precast column corbel beam reinforcement connection of this utility model;

[0023] Figure 5 This is a structural schematic diagram of the front axonometric view of the rigid connection achieved by welding the upper beam of the bracket according to this utility model;

[0024] Figure 6 This is a structural schematic diagram of the front axonometric view of the column core in the beam-column joint area of ​​this utility model.

[0025] In the diagram: 1. Column body; 2. Corbel; 201. Horizontal bearing surface; 202. Embedded steel plate; 3. Embedded dry connection system; 301. Lower connector; 302. Upper connector; 4. Column core structure in beam-column joint area; 5. Diagonal reinforcing bars; 6. Stirrups; 7. Bearing plate; 8. Reinforcing bar mechanical sleeve; 9. Short reinforcing bars; 10. Steel pipe-UHPC assembly. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0027] Please see Figure 1-6 This utility model provides a technical solution:

[0028] A precast multi-story corbel column includes: a column body 1, a corbel 2, a pre-embedded dry connection system 3, and a column core structure 4 in the beam-column joint area; the column body 1 is a factory-precast reinforced concrete component, the length of which spans at least two standard floors; at the design position of the column body 1 corresponding to the bottom elevation of the beam on each floor, an outwardly protruding corbel 2 is integrally formed; the corbel 2 is internally configured with dense diagonal reinforcing bars 5 and stirrups 6; the pre-embedded dry connection system 3 includes a lower connector 301 pre-embedded on the top surface of the corbel 2 and a matching upper connector 302 pre-embedded at the end of the precast beam; the column core structure 4 in the beam-column joint area is a steel pipe pre-embedded in the column core position of the beam-column joint area, the inside of the steel pipe is filled with ultra-high performance concrete, forming a steel pipe-UHPC composite 10. By setting up factory-prefabricated columns 1 spanning at least two standard floors (column concrete strength grade not lower than C40, longitudinal reinforcing steel using HRB400E seismic steel), corbels 2 integrally formed with the columns, dense diagonal reinforcing steel 5 (diameter Φ20-Φ25) and stirrups 6 (diameter Φ8-Φ10) with an inner spacing of 100-150mm in the corbels, and a steel pipe-UHPC composite body 10 made of Q355B steel pipe (wall thickness 8-12mm) and ultra-high performance concrete with a compressive strength ≥120MPa, the following effects are achieved: reducing the number of column-to-column connection nodes by more than 50% in the traditional "one column per floor" design; eliminating interface hazards of on-site splicing between corbels and columns; improving the shear and bending resistance of corbels by more than 30% through dense reinforcing steel; and utilizing the circumferential constraint of steel pipes and the high toughness of UHPC to form a rigid core for the nodes, increasing the ductility of the nodes to 1.5 times that of traditional nodes, significantly reducing the risk of structural failure caused by a large number of spliced ​​nodes, and improving the overall reliability.

[0029] One end of the diagonal reinforcing bar 5 is anchored in the core area of ​​column 1, and the other end extends to the bearing plate 7 at the outer edge of corbel 2. By setting a diagonal reinforcing bar 5 with one end anchored in the core area of ​​column 1 (anchorage length not less than 35d, where d is the diameter of the reinforcing bar) and the other end extending to the bearing plate 7 (the angle between the reinforcing bar and the column axis is 45°-60°, adapting to the load transfer path at the beam end), the vertical and horizontal loads borne by the beam end on corbel 2 are efficiently transferred to the core area of ​​column, avoiding harmful cracks with a width ≥0.2mm at the root of corbel due to stress concentration. At the same time, the anchorage length of the reinforcing bar ensures the continuity of force transfer, controlling the stress fluctuation of the beam-column connection within 5%, further ensuring the stability of the stress.

[0030] The bearing plate 7 is fixedly connected to the extension end of the inclined reinforcing bar 5 to transfer the beam end load of the precast beam. By setting the bearing plate 7 (made of Q235 steel plate, 12-16mm thick, with an area not less than 1.2 times the cross-sectional area of ​​the outer edge of the corbel) to the extension end of the inclined reinforcing bar 5 (welded with double-sided fillet welds, with a weld height of not less than 8mm), the concentrated load at the end of the precast beam is transformed into a linear force evenly distributed on the inclined reinforcing bar. This reduces the compressive stress of the concrete at the outer edge of the corbel to below 80% of the design limit, preventing concrete crushing. At the same time, the rigidity of the steel plate disperses the local load, improving the load transfer reliability of the corbel to over 95%, further enhancing the bearing capacity.

[0031] The top surface of the bracket 2 is a horizontal bearing surface 201. A pre-embedded steel plate 202 is embedded in the horizontal bearing surface 201. The pre-embedded steel plate 202 is matched with the lower connector 301 of the pre-embedded dry connection system 3. By setting a horizontal bearing surface 201 on the top surface of the corbel 2 (flatness error ≤2mm / m, controlled by laser leveling process) and a pre-embedded steel plate 202 (material Q235, size 20-30mm larger than the lower connector 301 to ensure coverage of the entire load-bearing surface of the connector) and a lower connector 301 (using pre-embedded bolt group, bolt diameter Φ16-Φ20), a flat support foundation with a fit of ≥98% is achieved for the precast beam. At the same time, the pre-embedded steel plate 202 disperses the stress of the lower connector 301 to the corbel concrete (reducing the stress of the concrete around the connector by 20%), avoiding loosening and displacement of the connector when it is under tension or compression (displacement ≤0.5mm), thus laying the foundation for the precise docking of the subsequent dry connection (alignment error ≤3mm).

[0032] The upper connector 302 of the pre-embedded dry connection system 3 is a connecting steel plate pre-embedded in the end of the precast beam, and the position of the connecting steel plate corresponds precisely to the position of the lower connector 301. By setting a connecting steel plate (upper connector 302, thickness 10-14mm, with positioning holes matching the bolts, hole diameter error ≤0.5mm) pre-embedded in the end of the precast beam (welded and fixed to the reinforcing steel bars at the beam end, with a welding length of not less than 10d) and whose position corresponds precisely to the lower connector 301, rapid alignment with the bracket 2 is achieved during the hoisting of the precast beam (using a total station for positioning), shortening the on-site adjustment time to less than 30 minutes, reducing the time spent on high-altitude operations (reducing high-altitude adjustment operations by 50%), while ensuring the docking accuracy of the connectors (alignment deviation ≤3mm), avoiding uneven stress on the node due to deviation (stress deviation controlled within 10%), and further ensuring the performance of the node.

[0033] The upper connector 302 and the lower connector 301 are rigidly connected by on-site welding to transfer bending moment and shear force at the beam end. By setting up a rigid on-site welding connection between the upper connector 302 and the lower connector 301 (using manual arc welding, E4303 welding rod, weld height not less than 0.8 times the thickness of the connector, 100% visual inspection and 20% non-destructive testing), the efficiency of transferring bending moment and shear force at the precast beam end is increased to over 90%, forming a rigid node with mechanical performance fluctuation ≤5%. This avoids node deformation caused by traditional flexible connections (such as bolt connections) (deformation is controlled within L / 500, where L is the calculated span of the beam end), enabling the node's shear bearing capacity and bending bearing capacity to reach over 95% and 92% of the "equivalent to cast-in-place" node, respectively, making it easier to meet design requirements.

[0034] The precast beam ends are pre-embedded with steel bar mechanical sleeves 8, and short steel bars 9 are provided on site. By setting up the pre-embedded steel bar mechanical sleeves 8 (using straight thread sleeves, conforming to GB / T39600 standard, with a sleeve length of not less than 40mm) and the short steel bars 9 provided on site (with a diameter consistent with the bottom reinforcement of the beam, Φ20-Φ25), it is possible to avoid directly extending the bottom reinforcement of the precast beam into the core area of ​​the column (avoiding dense intersection of beam and column reinforcement), thereby improving the efficiency of steel bar binding during precast beam factory production by 30%, reducing the space occupied by components during on-site hoisting by 25%, and preventing the steel bar density in the joint area from exceeding the 3% limit (actual density is controlled within 2.5%), solving construction difficulties (binding time is shortened by 40%), and further improving the convenience of joint construction.

[0035] One end of the short reinforcing bar 9 is connected to the reinforcing bar mechanical sleeve 8, and the other end extends into the post-cast area of ​​the node. By setting up a short reinforcing bar 9 (using HRB400E steel bars with rust-proof surface treatment) with one end connected to the reinforcing bar mechanical sleeve 8 (using a straight thread connection, tightening torque meeting the specification requirements, torque error ≤5%) and the other end extending into the post-cast area of ​​the node (extending length not less than 30d, with a 180° hook at the end), a reliable connection between the precast beam reinforcing bars and the node area is achieved (connection strength not less than 95% of the standard value of the tensile strength of the reinforcing bars). After the post-cast area concrete (strength grade C40, using shrinkage-compensating concrete) is poured, the beam reinforcement and the node form a complete stress system (cooperation coefficient ≥0.95), further enhancing the cooperative working ability of the node (overall node stiffness increased by 15%) and the structural ductility (ductility coefficient increased to 1.8).

[0036] The standard number of floors spanned by column 1 is 2-4. The dimensions of corbel 2 for each floor are designed based on the beam load parameters of that floor. By setting a reasonable range for column 1 spanning 2-4 floors (2 floors are suitable for buildings with a span of 10-15m, and 3-4 floors are suitable for buildings with a span of 8-12m) and designing the dimensions of corbel 2 according to the beam load parameters of each floor (e.g., 20kN / m for 2 floors and 18kN / m for 3 floors), the structural applicability is achieved (suitable for 8-15m span buildings). The design balances the advantages of multi-story buildings with spans of up to 100m with economic efficiency (reducing column material usage by 15%-20% and ensuring that corbel material usage matches load requirements without waste). It avoids transportation difficulties (transport weight controlled within 50t, suitable for conventional flatbed trucks) and hoisting risks (hoisting height ≤20m, suitable for conventional truck cranes) caused by excessively large column spans (more than 4 stories). It also prevents corbel dimensions from being too large (material waste rate ≤5%) or too small (load capacity reserve ≥1.2 times the design value), ensuring that the components are adapted to the load requirements of different multi-story buildings.

[0037] The corbel 2 and column 1 are formed by a one-time factory casting process. By setting up a one-time factory casting process for corbel 2 and column 1 (using steel mold casting, mold turnover ≥50 times, concrete pumping, slump 180-220mm, vibration frequency 50-60Hz), combined with standard curing (temperature 20±2℃, humidity ≥90%, curing for 28 days) or steam curing (heating rate ≤15℃ / h, constant temperature 50±5℃, curing time 12h), the problems of poor interface bonding (interface bond strength increased to 98% of concrete of the same strength) and insufficient concrete density (density ≥99%, no internal defects detected by ultrasonic flaw detection) that occur when casting corbels on site are avoided. This ensures that the corbel and column form a complete load-bearing whole (overall mechanical performance fluctuation ≤3%), reduces the amount of on-site wet work (wet work reduced by 80%), and improves the stability and consistency of component production quality (dimensional error ≤2mm, appearance qualification rate ≥98%).

[0038] Working principle: Based on design parameters (floor height, beam load, seismic grade), a steel mold is used to create the column body 1 mold. The longitudinal reinforcing bars (HRB400E) of the column body, the diagonal reinforcing bars 5 (Φ20-Φ25) of the corbel 2, and the stirrups 6 (Φ8-Φ10) are arranged inside the mold. Simultaneously, Q355B steel pipes are pre-embedded in the beam-column joint area (forming the column core structure 4 in the beam-column joint area). A pre-embedded steel plate 202 and a lower connecting piece 301 are fixed to the top surface of the corbel. Then, C40 or higher grade concrete is pumped to pour the column body and corbel. High-frequency vibration (frequency 50-60Hz) is used to ensure compaction. After curing to 100% of the design strength, ultra-high performance concrete (compressive strength ≥120MPa) is poured into the steel pipe, forming a steel pipe-UHPC assembly 10, completing the precast column production. Simultaneously, a reinforcing bar mechanical sleeve 8 and an upper connecting piece 302 are pre-embedded at the end of the precast beam to ensure the dimensional accuracy of the component (error ≤2mm).

[0039] Precast multi-layer corbel columns were hoisted to the design position using a truck crane and temporarily fixed after being positioned using a total station (error ≤ 3mm). Then, precast beams were hoisted, ensuring precise alignment of the upper beam connector 302 with the lower corbel connector 301 (alignment error ≤ 3mm). These were then welded together using manual arc welding (weld height ≥ 0.8 times the connector thickness). Next, one end of the short reinforcing bar 9 was connected to the mechanical sleeve 8 of the precast beam via a straight thread (tightening torque conforming to specifications), and the other end was extended into the post-cast area of ​​the node (extension length ≥ 30d). Finally, C40 shrinkage-compensating concrete was poured into the post-cast area of ​​the node, and after curing to the design strength, the entire assembly was completed. The entire process involved minimal wet work, significantly improving assembly efficiency compared to traditional methods.

[0040] The vertical loads (such as floor live loads and dead loads) borne by the precast beam are first transferred to the horizontal bearing surface 201 of the corbel 2 through the beam end. Part of the load is directly transferred to the column 1 through the horizontal bearing surface, and another part is transferred to the inclined reinforcing steel 5 (the steel bar makes an angle of 45°-60° with the column axis) through the bearing plate 7, and then transferred to the core area of ​​the column through the anchorage end of the steel bar. The bending moment and shear force at the beam end are transferred to the corbel and column through the welded joint between the upper connector 302 and the lower connector 301. At the same time, the short steel bar 9 and the concrete in the post-cast area of ​​the joint work together to transfer the stress of the beam reinforcement to the joint area, forming a "multi-path load transfer" system to ensure that the load transfer efficiency is ≥90% and avoid local stress concentration.

[0041] Under seismic loading, the beam-column joint area needs to resist horizontal shear force and bending moment. At this time, the steel pipe-UHPC composite 10 plays a core role. The circumferential constraint effect of the steel pipe restricts the lateral deformation of the UHPC, enabling the UHPC to maintain high compressive strength and toughness, forming a "rigid joint core". At the same time, the cross-story column 1 reduces column-column connection nodes, avoiding inter-story nodes from becoming weak links in seismic resistance. Since the joint rigidity is stronger than the beam, plastic hinges are preferentially formed at the beam ends (the junction of the post-cast area and the precast beam), which conforms to the seismic design principle of "strong column-strong joint-weak beam", realizing the safe and stable operation of the structure under normal and extreme conditions.

[0042] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A prefabricated multi-layer corbel column, characterized in that, include: The column body, corbel, pre-embedded dry connection system, and column core structure in the beam-column joint area; the column body is a factory-prefabricated reinforced concrete component whose length spans at least two standard floors; At the design position of the column body corresponding to the bottom elevation of each floor beam, an outwardly protruding corbel is integrally formed; the corbel is internally configured with dense diagonal reinforcing bars and stirrups; the pre-embedded dry connection system includes a lower connector pre-embedded on the top surface of the corbel and a matching upper connector pre-embedded at the end of the precast beam; the column core structure of the beam-column joint area is a steel pipe pre-embedded at the column core position of the beam-column joint area, and the inside of the steel pipe is filled with ultra-high performance concrete to form a composite.

2. The prefabricated multi-layer corbel column according to claim 1, characterized in that: One end of the inclined reinforcing bar is anchored inside the column, and the other end extends to the bearing plate at the outer edge of the corbel.

3. A prefabricated multi-layer corbel column according to claim 2, characterized in that: The pressure plate is fixedly connected to the extension end of the inclined reinforcing steel bar and is used to transfer the beam end load of the precast beam.

4. A prefabricated multi-layer corbel column according to claim 1, characterized in that: The top surface of the corbel is a horizontal bearing surface, and a pre-embedded steel plate is embedded in the horizontal bearing surface. The pre-embedded steel plate is configured to cooperate with the lower connecting parts of the pre-embedded dry connection system.

5. A prefabricated multi-layer corbel column according to claim 1, characterized in that: The upper connector of the pre-embedded dry connection system is a connecting steel plate pre-embedded at the end of the precast beam, and the position of the connecting steel plate corresponds to the position of the lower connector.

6. A prefabricated multi-layer corbel column according to claim 1, characterized in that: The upper and lower connectors are rigidly connected by welding to transfer the bending moment and shear force at the beam end.

7. A prefabricated multi-layer corbel column according to claim 1, characterized in that: The precast beam ends are pre-embedded with steel bar mechanical sleeves.

8. A prefabricated multi-layer corbel column according to claim 7, characterized in that: One end of a short steel bar is connected to a steel bar mechanical sleeve, and the other end extends into the post-cast zone of the node.

9. A prefabricated multi-layer corbel column according to claim 1, characterized in that: The column spans 2-4 standard floors, and the corbel dimensions for each floor are matched with the beam load parameters of that floor.

10. A prefabricated multi-layer corbel column according to claim 1, characterized in that: The corbel and column body are cast in one piece at the factory.

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