Plastic hinge-controllable full-length column assembled frame structure and construction method
By adjusting the reinforcement parameters of precast continuous columns and joint areas, the problems of multiple column-to-column connection nodes and insufficient control of plastic hinge zones in prefabricated concrete frame structures were solved, thus realizing a prefabricated frame structure with efficient construction and seismic safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TONGJI UNIV
- Filing Date
- 2026-05-12
- Publication Date
- 2026-06-09
AI Technical Summary
Existing prefabricated concrete frame structures suffer from numerous column-to-column connection nodes, a large amount of on-site wet work, congested reinforcement in the core area of the nodes, low construction efficiency, and a lack of proactive control over the plastic hinge zone. These issues make the node area a potential weak point, affecting seismic safety.
Precast continuous columns are used as a continuous vertical load-bearing skeleton. By setting continuous longitudinal bars and lapped longitudinal bars at the beam ends in the precast continuous columns, and combining them with additional lapped connection bars on the side of the column, the plastic hinge can be lapped and connected in the node area. By adjusting the reinforcement parameters and reinforcement measures in the node area, the plastic hinge can be controlled and adjusted.
It effectively reduces column-to-column connection nodes, improves construction efficiency and construction quality in the node area, enables the designable and controllable formation of plastic hinges, and enhances the overall integrity, seismic performance and energy dissipation capacity of the structure.
Smart Images
Figure CN122169580A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of prefabricated concrete frame structure technology, and in particular to a prefabricated frame structure with adjustable plastic hinges and a construction method for a continuous column. Background Technology
[0002] Prefabricated concrete frame structures offer advantages such as high levels of industrialization in construction, short construction periods, low resource consumption, and environmental friendliness, making them a crucial development direction for current building industrialization. With the advancement of building industrialization, prefabricated concrete frame structures are increasingly widely used in residential and public buildings.
[0003] Existing prefabricated concrete frame structures mostly employ a segmented assembly method using short columns. For example, patent document CN108035438A discloses a high-strength, high-ductility prefabricated concrete frame structure system. This system uses precast short columns with exposed longitudinal reinforcement in the core area of the joints, and the upper and lower columns are connected in the core area of the joints via the longitudinal reinforcement. This segmented assembly method requires the construction of column-to-column connection joints on each floor, resulting in a large number of connection joints, a significant amount of on-site wet work, and low construction efficiency. Furthermore, the complex reinforcement structure and limited construction space in the column-to-column connection areas can easily lead to insufficient concrete compaction or difficulty in ensuring grouting quality.
[0004] Regarding beam-column connections, traditional prefabricated concrete frame beam-column joints typically require beam-end reinforcement to penetrate deep into the joint core area. For example, patent document CN106149873A discloses a prefabricated concrete frame structure in which prefabricated beam ends are pre-embedded with beam-end reinforcing steel, which is bolted to the longitudinal reinforcing steel in the prefabricated column at the joint area. In this connection method, the beam-end reinforcement needs to be staggered with the column longitudinal reinforcement, stirrups, and other connecting components in the joint core area, resulting in reinforcement congestion in the joint core area, difficult construction operations, and increased positioning errors, thereby affecting the joint connection quality and overall load-bearing performance.
[0005] In terms of seismic design, prefabricated concrete frames should adhere to the ductility design principle of "strong columns, weak beams; strong joints, weak components," ensuring that plastic hinges preferentially form at beam ends and other ductile areas, rather than appearing in joint zones or columns. Patent document CN108775083A discloses a prefabricated concrete frame structure with external connections to the plastic hinge zone of precast beams. This structure features cantilever beams in the core joint area of precast columns, connected by U-shaped steel reinforcement loops at the ends of the cantilever beams and precast beams, placing the connection at a location of lower stress on the beam. However, existing prefabricated beam-column joints primarily focus on connection implementation, lacking proactive control over the plastic development zone and failure mode. This makes joint zones prone to becoming potential weak points, negatively impacting structural energy dissipation and seismic safety.
[0006] Therefore, a new structural system is needed that can reduce column-to-column connection nodes, improve assembly construction efficiency, solve the problem of steel reinforcement congestion in the core area of the nodes, and actively control the position of the plastic hinge zone to improve the seismic performance of the prefabricated concrete frame. Summary of the Invention
[0007] The purpose of this invention is to provide a prefabricated frame structure with adjustable plastic hinges and a continuous column, as well as a construction method, to solve the following technical problems existing in the prior art: (1) The traditional short column segmented assembly method requires the construction of a large number of column-to-column connection nodes. With many connection nodes, the amount of wet work on site is large and the construction efficiency is low. At the same time, the complex steel reinforcement structure and narrow construction space in the column-to-column connection area can easily lead to insufficient concrete compaction or difficulty in ensuring grouting quality. (2) Traditional beam-column assembly joints usually require the beam end reinforcement to penetrate deep into the core area of the joint and be arranged in an alternating manner with the column longitudinal reinforcement, stirrups and other connecting components. This results in crowded reinforcement in the core area of the joint, difficult construction operations, and increased positioning errors, which in turn affect the connection quality and overall stress performance of the joint. (3) Existing prefabricated beam-column joints focus on connection and lack active control over the plastic development zone and failure mode, which makes the joint area prone to become a potential weak point, which is not conducive to structural energy consumption and seismic safety.
[0008] To achieve the above objectives, the present invention adopts the following technical solution: A prefabricated frame structure with adjustable plastic hinge and continuous column, comprising: a prefabricated continuous column, wherein continuous longitudinal reinforcement is provided in the prefabricated continuous column along the column height direction, and multiple additional lap-connecting reinforcement bars are reserved on the side of the prefabricated continuous column; a prefabricated beam, wherein multiple outward lap-connecting longitudinal reinforcement bars are provided at the beam end; a node area, wherein the node area is formed by lap-connecting the additional lap-connecting reinforcement bars on the column side and the outward lap-connecting longitudinal reinforcement bars at the beam end, and the node area is subsequently filled with concrete; the plastic hinge is adjustable by adjusting the reinforcement parameters of the node area.
[0009] Furthermore, the precast continuous column has an integrally precast cantilever section on its side. Additional lapped reinforcing bars are installed within this cantilever section, and the cantilever section is lapped and connected to the longitudinal cantilever bars at the beam end within the joint area. By integrally precasting the cantilever section on the column side and implementing joint area reinforcement measures, the plastic hinge can be further moved from the precast beam end area to the precast cantilever section area on the column side, enabling flexible adjustment of the plastic hinge position and limiting damage to a pre-defined energy dissipation zone.
[0010] Preferably, the length of the overhang is 1.0 to 1.5 times the beam height. This length range ensures that the overhang has sufficient plastic energy dissipation length without increasing the structural weight due to excessive length.
[0011] Furthermore, The specific methods for adjusting the reinforcement parameters of the node area are as follows: Alternatively, when the node area is located on the column side, the additional lapped connecting steel bars on the column side and the extended lapped longitudinal steel bars at the beam end are configured in one of the following ways: the number of steel bars on the column side is greater than the number of steel bars at the beam end; double-layer steel bars are set on the column side while single-layer steel bars are set at the beam end; or the diameter of the steel bars on the column side is greater than the diameter of the steel bars at the beam end. This ensures that the bearing capacity of the node area is higher than that of the adjacent precast beam, thereby controlling the plastic hinge to appear only in the target precast beam end area, rather than in the node area. Alternatively, when the node area is separated from the column side, the additional lapped connection steel bars on the column side and the extended lapped longitudinal bars at the beam end are configured in one of the following ways: the number of steel bars on the column side is less than the number of steel bars at the beam end; a single layer of steel bars is set on the column side while a double layer of steel bars is set at the beam end; or the diameter of the steel bars on the column side is smaller than the diameter of the steel bars at the beam end. This makes the bearing capacity of the node area higher than that of the adjacent precast extended section on the column side, so as to control the plastic hinge to appear only in the target precast extended section area, rather than in the node area.
[0012] By employing precast continuous columns as a continuous vertical load-bearing skeleton, the longitudinal reinforcement within the column is continuously arranged along the column height without interruption, effectively reducing the large number of repetitive column-to-column connection nodes in the traditional segmented assembly of short columns, reducing on-site wet work, and improving construction efficiency and the overall integrity of the column components. Simultaneously, the beam-column connection location is moved from the traditional node core area to the side of the precast continuous column. Through additional lapped connection reinforcement on the column side and lapped connection reinforcement at the beam end, the problem of reinforcement congestion and limited construction space in the node core area is effectively solved, improving the node construction quality and connection reliability. By adjusting the reinforcement configuration (number of bars, number of layers, or diameter) on the column side and beam end, the bearing capacity of the node area is made higher than that of the adjacent precast area, realizing a ductile failure mechanism of "strong node, weak component," with plastic hinges controllably formed at the precast beam end or precast overhang.
[0013] Furthermore, the concrete poured in the joint area is concrete with a strength grade of not less than C40 or ECC material. Using concrete with a strength grade of not less than C40 or ECC material can further improve the bearing capacity, shear resistance, and deformation capacity of the joint area, thereby enhancing its stress performance.
[0014] Furthermore, the stirrups in the node area are densified. Densifying the stirrups in the node area can improve the shear bearing capacity of the node area, prevent shear failure, and ensure the safety of the node area.
[0015] Furthermore, the connection interface between the side of the precast continuous column and the end of the precast beam is manually roughened. This roughening process enhances the mechanical interlocking and shear resistance between the new and old concrete interfaces, improving the integrity and connection reliability of the joint area.
[0016] Furthermore, at the edge column joint of the frame structure, one end of the additional lapped connecting steel bar is bent and anchored inside the edge column at a 90-degree angle. The horizontal section length is not less than 0.4 times the basic seismic anchorage length and extends to the inside of the column longitudinal reinforcement, while the bent section length is not less than 15 times the steel bar diameter. This bent-anchor structure ensures the reliability of the steel bar anchorage at the edge column joint, prevents steel bar pull-out damage, and meets the seismic design requirements.
[0017] Furthermore, the lap joints of the additional lapped reinforcing bars and the extended lapped longitudinal bars adopt a 90-degree hook structure or an end-welded anchor plate structure. Using a 90-degree hook structure simplifies the reinforcing bar connection construction and improves anchorage reliability; using an end-welded anchor plate structure reduces the length of the bent section of the reinforcing bar, saving steel consumption.
[0018] This invention also provides a construction method for the above-mentioned adjustable plastic hinge full-length column prefabricated frame structure, comprising the following steps: S1: prefabricating the prefabricated full-length column and the prefabricated beam; S2: hoisting the prefabricated full-length column; S3: hoisting the prefabricated beam, tying and lapping the extended longitudinal reinforcement at the beam end with the additional lapped reinforcement on the column side, and increasing the stirrup density in the joint area; S4: pouring concrete in the joint area. This construction method has clear steps, is easy to operate, and can effectively ensure the construction quality of the structural system.
[0019] Preferably, in step S4, concrete or ECC material with a strength grade of not less than C40 is poured. Using concrete or ECC material with a strength grade of not less than C40 can further improve the bearing capacity and deformation capacity of the joint area, and enhance the seismic performance of the structure.
[0020] Compared with the prior art, the present invention has at least the following beneficial effects: (1) Using prefabricated continuous columns as a continuous vertical load-bearing skeleton effectively reduces the large number of repetitive column-to-column connection nodes in the traditional segmented assembly of short columns, reduces the amount of wet work on site, improves construction efficiency and the integrity of column components, and the overall integrity, stiffness continuity and seismic force transmission path of the structure are superior to the segmented assembly system of short columns; (2) The beam-column connection location is moved from the traditional node core area to the side of the precast continuous column. The complex connection in the core area is replaced by the column side binding lap connection, which effectively solves the problems of steel congestion and limited construction space in the node area, and improves the node construction quality and connection reliability. (3) Through the parametric reinforcement of the joint area (different number of bars, double-layer steel bars or different diameter), the reinforcement of concrete with a post-cast strength grade of not less than C40 or ECC material, the densification of stirrups and the roughening of the interface, the bearing capacity of the joint area can be higher than the target plastic zone of the adjacent precast beam or precast overhang, thus forming a ductile failure mechanism of "strong joint, weak component", realizing the designable and controllable formation of plastic hinge at the end of the precast beam or the overhang of the column side, limiting the damage to the preset energy dissipation zone, and improving the integrity, structural ductility, energy dissipation capacity and seismic safety reserve of the joint area. Attached Figure Description
[0021] Figure 1 A schematic diagram of a precast concrete frame structure system with continuous columns, where the plastic hinge zone appears at the end of the precast beam after hoisting and construction are completed.
[0022] Figure 2 A schematic diagram of a prefabricated concrete frame structure with a continuous column and controlled plastic hinge zone appearing in the precast overhang section after hoisting construction is completed.
[0023] Figure 3 shows a schematic diagram of the precast continuous column edge node and the precast beam structure, specifically Figure 3(a) and Figure 3(b).
[0024] Figure 4 This is a schematic diagram of the node structure in a prefabricated continuous column.
[0025] Figure 5 shows the structural schematic diagrams of the full-length column edge node with prefabricated extension section on the column side and the full-length column middle node with prefabricated extension section on the column side, specifically Figure 5(a) and Figure 5(b).
[0026] Figure 6 shows a schematic diagram of a beam-column joint structure in which the plastic hinge zone appears at the end of a precast beam using differential reinforcement, double-layer functional separation reinforcement, and differential diameter reinforcement methods. Specifically, these are Figure 6(a), Figure 6(b), and Figure 6(c).
[0027] Figure 7 shows a schematic diagram of a beam-column joint structure in which the plastic hinge zone appears on the precast overhang section on the column side using differential reinforcement, double-layer functional separation reinforcement and differential diameter reinforcement methods. Specifically, these are Figure 7(a), Figure 7(b), and Figure 7(c).
[0028] Figure 8 shows a structural diagram of the lapped steel bar ends using 90-degree hooks and welded anchor plates, specifically Figure 8(a) and Figure 8(b).
[0029] Figure 9 This is a schematic diagram of the connection structure between the column and the foundation.
[0030] Figure 10 This is a schematic diagram of a beam-slab connection structure.
[0031] Figure 11 This is a schematic diagram of the hoisting construction sequence for the frame structure. Detailed Implementation
[0032] The specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. The meanings of the markings in the drawings are as follows: precast slab 1, lapped longitudinal reinforcement at the slab end 1-1; precast continuous column 2, continuous longitudinal reinforcement inside the column 2-1, additional lapped connecting reinforcement on the side of the column 2-2, column stirrups 2-3, embedded steel sleeve 2-4, additional reinforcement on the side of the column 2-5, precast extended section on the side of the column 2-6; node area 3; precast beam 4, lapped longitudinal reinforcement at the beam end 4-1, beam stirrups 4-2, additional reinforcement at the beam end 4-3, post-cast composite layer above the beam 4-4; foundation 5, foundation reinforcement 5-1; anchor plate 6.
[0033] Example 1 This embodiment provides a continuous column prefabricated frame structure for controlling the occurrence of plastic hinges in the four-end regions of the target precast beam, such as... Figure 1 Figure 3 Figure 4 Figure 6(a), Figure 6(b), Figure 6(c), Figure 8(a) Figure 9 As shown, it includes precast continuous columns 2, precast beams 4, precast slabs 1, and node areas 3.
[0034] The precast continuous column 2 is constructed using a three-layer continuous precasting method, with a column height of 9 meters, each layer being 3 meters, and a column cross-section of 400 mm × 400 mm. For example, and not as a limitation, the continuous longitudinal reinforcement 2-1 consists of 12 HRB400 grade steel bars with a diameter of 20 mm, continuously arranged without interruption along the column height. The column stirrups 2-3 are HPB300 grade steel bars with a diameter of 8 mm, spaced 150 mm apart along the column height. The connection ends of the continuous longitudinal reinforcement 2-1 are pre-embedded steel sleeves 2-4 for grouting sleeve connection with the foundation reinforcement 5-1 of the foundation 5.
[0035] In this embodiment, a prefabricated frame structure with adjustable plastic hinges using a differential number of reinforcement nodes is provided, as shown in Figure 6(a). Additional lapped connecting steel bars 2-2 are pre-installed on the side of the prefabricated continuous column 2 at the beam-column connection node. In this embodiment, the prefabricated continuous column 2 is an edge column, with four 18mm diameter HRB400 grade additional lapped connecting steel bars 2-2 pre-installed at the top and bottom of the column side. One end of the additional lapped connecting steel bar 2-2 is bent and anchored inside the edge column at a 90-degree angle. The horizontal section is 300mm long, not less than 0.4 times the basic seismic anchorage length, and extends to the inside of the continuous longitudinal reinforcement 2-1 within the column. The bent section is 270mm long, not less than 15 times the steel bar diameter. This bent-anchor structure ensures the reliability of the steel bar anchorage at the edge column node, preventing pull-out failure of the steel bars under seismic action.
[0036] As shown in Figure 6(a), precast beam 4 is a composite beam with a cross-sectional dimension of 300 mm × 600 mm. Three 18 mm diameter HRB400 grade longitudinal reinforcement bars 4-1 are installed at the top and bottom of the beam ends, with an extension length of 350 mm. The lap connection of the beam end longitudinal reinforcement bars 4-1 adopts a 90-degree hook structure, as shown in Figure 8(a), with a hook length of 216 mm, which is not less than 12 times the diameter of the reinforcement bar. Beam stirrups 4-2 are 8 mm diameter HPB300 grade steel bars, arranged at 150 mm intervals along the beam span.
[0037] The formation process of node area 3 is as follows: During on-site construction, the three beam-end extended lapped longitudinal bars 4-1 at the ends of the precast beam 4 are lapped together with the four column-side additional lapped connecting bars 2-2 on the sides of the precast continuous column 2. As shown in Figure 6(a), since there are four column-side bars and three beam-end bars, they are lapped in a staggered manner: two of the four column-side additional lapped connecting bars 2-2 are lapped together with one of the three beam-end extended lapped longitudinal bars 4-1 at the beam ends, staggered along the beam axial direction, and the remaining bars are lapped one by one. The lap length of the straight section of the bar is 280 mm. This staggered lapping method avoids the concentrated arrangement of lap joints in the node area, making the stress in the node area more uniform.
[0038] After completing the lap splicing of the reinforcing bars, the stirrups in joint area 3 are reinforced with a spacing of 100 mm. Simultaneously, the interface between the side of the precast continuous column 2 and the end of the precast beam 4 was manually roughened during the factory prefabrication stage to a depth of 3 to 5 mm to enhance the mechanical interlocking and shear resistance between the new and old concrete interfaces. C40 high-strength concrete or ECC material is then poured into joint area 3 and thoroughly vibrated to ensure compaction.
[0039] Through the above structural configuration, the number of additional lapped reinforcing bars 2-2 on the column side (4 bars) is greater than the number of extended lapped longitudinal reinforcing bars 4-1 at the beam end (3 bars), forming a differential reinforcement. Combined with measures such as increased stirrup density in the joint area, roughening of the interface, and post-cast C40 high-strength concrete or ECC material, the bearing capacity of joint area 3 is higher than that of the adjacent precast beam 4. Under seismic loading, plastic hinges preferentially form at the ends of precast beam 4, rather than in joint area 3, thus achieving a ductile failure mechanism of "strong joint, weak member".
[0040] In this embodiment, a prefabricated frame structure with adjustable plastic hinges using double-layer functional separation nodes is also provided, as shown in Figure 6(b). In this embodiment, the prefabricated continuous column 2 is an edge column, with four 18 mm diameter HRB400 grade additional lapped connecting steel bars 2-2 and four 18 mm diameter HRB400 grade additional steel bars 2-5 pre-reserved on the upper and lower parts of the column side. The additional steel bars 2-5 are located below the additional lapped connecting steel bars 2-2, and the distance between them should not be less than 25 mm. Four 18 mm diameter HRB400 grade beam end overhanging lapped longitudinal bars 4-1 are pre-reserved on the upper and lower parts of the prefabricated beam 4.
[0041] The formation process of node area 3 is as follows: During on-site construction, the four beam-end extended lapped longitudinal bars 4-1 at the ends of the precast beam 4 are lapped together with the four column-side additional lapped connecting bars 2-2 on the sides of the precast continuous column 2. As shown in Figure 6(b), since the column-side bars are double-layered and the beam-end bars are single-layered, during the lapped connection of the node area, the four column-side additional lapped connecting bars 2-2 and the beam-end extended lapped longitudinal bars 4-1 are lapped one by one along the beam axis. The lap length of the straight section of the bars is 280 mm. The column-side additional bars 2-5 do not participate in the lapped connection and are only used to reinforce node area 3. Other implementation methods are the same as described above.
[0042] In this embodiment, a prefabricated frame structure with adjustable plastic hinges using differential diameter reinforced nodes is also provided, as shown in Figure 6(c). In this embodiment, the prefabricated continuous column 2 is an edge column, with four 22 mm diameter HRB400 grade additional lapped connecting steel bars 2-2 pre-reserved at the top and bottom of the column side. Four 18 mm diameter HRB400 grade beam end overhanging lapped longitudinal bars 4-1 are pre-reserved at the top and bottom of the prefabricated beam 4.
[0043] The formation process of node area 3 is as follows: During on-site construction, the four 18 mm diameter longitudinal bars 4-1 extending from the ends of the precast beam 4 are lapped together with the four 22 mm diameter additional lapped connecting bars 2-2 on the sides of the precast continuous column 2. As shown in Figure 6(c), during the lap connection of the node area, the four additional lapped connecting bars 2-2 on the column side are lapped together with the beam end longitudinal bars 4-1 one by one along the beam axis. The lap length of the straight section of the reinforcing bars is 280 mm. Other implementation methods are the same as described above.
[0044] The working principle of the structural system in this embodiment is as follows: The precast continuous column 2 serves as a continuous vertical load-bearing skeleton, with its continuous longitudinal reinforcement 2-1 running uninterrupted along the column height, avoiding the construction of numerous inter-story column-to-column connection nodes as in the traditional short column segmented assembly method. When the frame structure bears vertical loads, the load is transferred to the node area 3 through the precast beam 4, and then transferred from the node area 3 to the precast continuous column 2 through the synergistic effect of the additional lapped connecting steel bars 2-2 on the column side and the continuous longitudinal reinforcement 2-1 inside the column, and finally to the foundation 5. When the frame structure bears horizontal seismic forces, since the bearing capacity of the node area 3 is higher than that of the adjacent precast beam 4, a plastic hinge is formed at the end of the precast beam 4, the beam end undergoes plastic rotation and dissipates seismic energy, while the node area 3 remains in an elastic state, ensuring the reliability of the beam-column connection and the seismic safety of the structure.
[0045] The construction method in this embodiment includes the following steps: Step S1: Prefabricate the continuous column 2, prefabricated beam 4, and prefabricated slab 1 in the factory. The continuous column 2 is prefabricated in three layers, with continuous longitudinal reinforcement 2-1 arranged continuously inside the column. The column base is pre-embedded with steel sleeves 2-4, and additional lapped connecting reinforcement 2-2 (and additional reinforcement 2-5) is reserved on the side of the column. The ends of the prefabricated beam 4 are reserved with extended lapped longitudinal reinforcement 4-1 (and additional reinforcement 4-3).
[0046] Step S2: At the factory, the connection interface between the side of the precast continuous column 2 and the end of the precast beam 4 is manually roughened to a depth of 3 to 5 mm.
[0047] Step S3: Hoist the precast continuous column 2 onto the foundation 5 on site, as follows: Figure 9 As shown, the continuous longitudinal reinforcement 2-1 inside the column is connected to the foundation reinforcement 5-1 by a grouting sleeve through a pre-embedded steel sleeve 2-4.
[0048] Step S4: The precast continuous columns are hoisted in the order of side columns to middle columns, and the precast beams are hoisted in the order of bottom to top. Figure 10 As shown. After the formwork and supports are erected in the beam-column joint area, the longitudinal reinforcement 4-1 extending outward from the end of the precast beam 4 is tied and lapped to the additional lapped reinforcement 2-2 on the side of the precast continuous column 2. The stirrups in the joint area 3 are then reinforced with a spacing of 100 mm.
[0049] Step S5: Pour C40 high-strength concrete or ECC material into node area 3 and compact it by vibration.
[0050] Step S6: After the beam-column joint construction is completed, hoist the precast slab 1 and complete the beam-slab connection construction, as follows. Figure 11 As shown. The precast slab 1 is placed on the precast beam 4. The lapped longitudinal reinforcement 1-1 at the end of the slab extends directly into the post-cast composite layer 4-4 above the beam, and the extension length is not less than 5 times the diameter of the reinforcement, and is lapped with the longitudinal reinforcement above the precast beam.
[0051] Step S7: Pour the composite layer concrete on top of node area 3 and precast beam 4 to finally complete the construction of the structural system of this embodiment.
[0052] This embodiment effectively reduces the number of column-to-column connection nodes and the amount of on-site wet work by using precast continuous columns 2 instead of traditional short column segmented assembly, thus improving construction efficiency. Simultaneously, by relocating the beam-column connection from the traditional node core area to the side of the precast continuous column, and replacing the complex core area connection with column-side lapped connections, the problems of congested reinforcement and limited construction space in the node core area are solved, improving the node construction quality and connection reliability. Through coordinated measures such as adjusting the reinforcement parameters of the node area, increasing the density of stirrups, roughening the interface, and post-casting C40 high-strength concrete or ECC materials, the bearing capacity of the node area is higher than that of the adjacent precast beams, achieving controllable formation of plastic hinges at the ends of the precast beams and improving the seismic performance of the structure.
[0053] Example 2 This embodiment provides a continuous column prefabricated frame structure that controls the occurrence of plastic hinges in the prefabricated overhanging sections 2-6 on the side of the target column, such as... Figure 2 Figures 3(b), 5, 7(a), 7(b), 7(c), and 8(a) Figure 9 As shown, it includes precast continuous columns 2, precast beams 4, precast slabs 1, and node areas 3.
[0054] The precast continuous column 2 has the same structural form as that in Example 1. The connection end of the continuous longitudinal reinforcement 2-1 in the column is pre-embedded with a steel sleeve 2-4, which is used to connect with the foundation reinforcement 5-1 of the foundation 5 through grouting sleeve connection.
[0055] In this embodiment, a prefabricated frame structure with adjustable plastic hinges using a differential number of reinforcement nodes is provided, as shown in Figure 7(a). Additional lapped reinforcement bars 2-2 are pre-installed on the side of the prefabricated continuous column 2 at the beam-column connection node. In this embodiment, the prefabricated continuous column 2 is an edge column, with three 18mm diameter HRB400 grade additional lapped reinforcement bars 2-2 pre-installed at the top and bottom of the column side. One end of the additional lapped reinforcement bars 2-2 is bent and anchored inside the edge column at a 90-degree angle, with a horizontal section length of 300mm, which is not less than 0.4 times the basic seismic anchorage length and extends to the inside of the continuous longitudinal reinforcement 2-1 within the column. The bent section length is 270mm, which is not less than 15 times the diameter of the reinforcement bar. This bent-anchor structure ensures the reliability of the reinforcement anchorage at the edge column node and prevents the reinforcement bars from being pulled out under seismic action.
[0056] As shown in Figure 7(a), precast beam 4 is a composite beam with a cross-sectional dimension of 300 mm × 600 mm. Four 18 mm diameter HRB400 grade longitudinal reinforcement bars 4-1 are installed at the top and bottom of the beam ends, with an extension length of 350 mm. The lap joint of the beam end longitudinal reinforcement bars 4-1 adopts a 90-degree hook structure, as shown in Figure 8(a), with a hook length of 216 mm, which is not less than 12 times the diameter of the reinforcement bar. Beam stirrups 4-2 are 8 mm diameter HPB300 grade steel bars, arranged at 150 mm intervals along the beam span.
[0057] The formation process of node area 3 is as follows: During on-site construction, the four beam-end extended lapped longitudinal bars 4-1 at the ends of the precast beam 4 are lapped together with the three column-side additional lapped connecting bars 2-2 on the sides of the precast continuous column 2. As shown in Figure 7(a), since there are three column-side bars and four beam-end bars, they are lapped in a staggered manner: one of the three column-side additional lapped connecting bars 2-2 is lapped with two of the four beam-end extended lapped longitudinal bars 4-1 at the beam ends, staggered along the beam axial direction, and the remaining bars are lapped one by one. The lap length of the straight section of the bar is 280 mm. This staggered lapping method avoids the concentrated arrangement of lap joints in the node area, making the stress in the node area more uniform.
[0058] After completing the lap splicing of the reinforcing bars, the stirrups in joint area 3 are reinforced with a spacing of 100 mm. Simultaneously, the interface between the side of the precast continuous column 2 and the end of the precast beam 4 was manually roughened during the factory prefabrication stage to a depth of 3 to 5 mm to enhance the mechanical interlocking and shear resistance between the new and old concrete interfaces. C40 high-strength concrete or ECC material is then poured into joint area 3 and thoroughly vibrated to ensure compaction.
[0059] Through the above structural configuration, the number of additional lapped reinforcing bars 2-2 on the column side (3 bars) is less than the number of extended lapped longitudinal reinforcing bars 4-1 at the beam end (4 bars), forming a differential reinforcement. Combined with measures such as increased stirrup density in the joint area, roughening of the interface, and post-cast C40 high-strength concrete or ECC material, the bearing capacity of joint area 3 is higher than that of the adjacent precast extended section 2-6 on the column side. Under seismic loading, plastic hinges preferentially form in the precast extended section 2-6 region on the column side, rather than in joint area 3, thus achieving a ductile failure mechanism of "strong joint, weak member".
[0060] In this embodiment, a prefabricated frame structure with adjustable plastic hinges using double-layer functional separation nodes is also provided, as shown in Figure 7(b). In this embodiment, the prefabricated continuous column 2 is an edge column, with four 18 mm diameter HRB400 grade additional lapped connecting steel bars 2-2 reserved at the top and bottom of the column side. At the top and bottom of the prefabricated beam 4, four 18 mm diameter HRB400 grade beam end overhanging lapped longitudinal bars 4-1 and four 18 mm diameter HRB400 grade beam end additional steel bars 4-3 are reserved, wherein the beam end additional steel bars 4-3 are located below the beam end overhanging lapped longitudinal bars 4-1, and the distance between the two should not be less than 25 mm.
[0061] The formation process of node area 3 is as follows: During on-site construction, the four beam-end extended lapped longitudinal bars 4-1 at the ends of the precast beam 4 are lapped together with the four column-side additional lapped connecting bars 2-2 on the sides of the precast continuous column 2. As shown in Figure 7(b), since the beam-end bars are double-layered and the column-side bars are single-layered, during the lapped connection of the node area, the four column-side additional lapped connecting bars 2-2 are lapped one by one with the beam-end extended lapped longitudinal bars 4-1 along the beam axis. The lap length of the straight section of the bars is 280 mm. The beam-end additional bars 4-3 do not participate in the lapped connection and are only used to reinforce node area 3. Other implementation methods are the same as described above.
[0062] In this embodiment, a prefabricated frame structure with adjustable plastic hinges using differential diameter reinforced nodes is also provided, as shown in Figure 7(c). In this embodiment, the prefabricated continuous column 2 is an edge column, with four 18 mm diameter HRB400 grade additional lapped connecting steel bars 2-2 pre-reserved at the top and bottom of the column side. Four 22 mm diameter HRB400 grade beam end overhanging lapped longitudinal bars 4-1 are pre-reserved at the top and bottom of the prefabricated beam 4.
[0063] The formation process of node area 3 is as follows: During on-site construction, the four 22 mm diameter longitudinal bars 4-1 extending outward from the end of the precast beam 4 are lapped together with the four 18 mm diameter additional lapped connecting bars 2-2 on the side of the precast continuous column 2. As shown in Figure 7(c), during the lap connection of the node area, the four additional lapped connecting bars 2-2 on the column side are lapped together with the beam end longitudinal bars 4-1 extending outward along the beam axis one by one. The lap length of the straight section of the reinforcing bars is 280 mm. Other implementation methods are the same as described above.
[0064] The working principle of the structural system in this embodiment is the same as that in Embodiment 1.
[0065] The construction method and steps in this embodiment are the same as those in Embodiment 1.
[0066] This embodiment achieves higher bearing capacity in the joint area than the precast cantilever section on the side of the adjacent column by adjusting the reinforcement parameters of the joint area, increasing the density of stirrups, roughening the interface, and pouring C40 high-strength concrete or ECC material in a coordinated manner. This realizes the controllable formation of plastic hinges in the precast cantilever section and improves the seismic performance of the structure.
[0067] In the above-described embodiments 1 and 2, the end structure of the lapped connection of the reinforcing bars in the node area 3 can be in the form of end-welded anchor plate 6, as shown in Figure 8(b), to further simplify the on-site reinforcing bar connection construction, reduce the length of the bent section of the reinforcing bars, and save steel consumption.
[0068] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A prefabricated frame structure with adjustable plastic hinges and continuous columns, characterized in that... ,include: A precast continuous column, wherein continuous longitudinal reinforcement bars are arranged continuously along the column height, and multiple additional lapped connection steel bars are reserved on the side of the precast continuous column; The precast beam has multiple outwardly extending lapped longitudinal reinforcement bars at its beam ends; The node area is formed by lapping the additional lapped connecting steel bars on the column side with the extended lapped longitudinal bars at the beam end, and the node area is subsequently filled with concrete. The plastic hinge can be adjusted by adjusting the reinforcement parameters of the steel bars in the node area.
2. The adjustable plastic hinge full-length column prefabricated frame structure according to claim 1, characterized in that... An extended section is integrally prefabricated on the side of the precast continuous column. Additional lapped connecting steel bars are provided in the extended section. The extended section and the extended lapped longitudinal bars of the beam end are lapped together in the node area.
3. The adjustable plastic hinge full-length column prefabricated frame structure according to claim 2, characterized in that... The length of the overhang is 1.0 to 1.5 times the beam height.
4. The adjustable plastic hinge full-length column prefabricated frame structure according to claim 1, characterized in that... The specific implementation methods for adjusting the reinforcement parameters of the node area are as follows: This method is applicable when the node area is located on the column side. The additional lapped connection reinforcement on the column side and the extended lapped longitudinal reinforcement at the beam end are configured in one of the following ways: the number of reinforcement bars on the column side is greater than the number of reinforcement bars at the beam end; double-layer reinforcement is set on the column side while single-layer reinforcement is set at the beam end; or the diameter of the reinforcement bars on the column side is greater than the diameter of the reinforcement bars at the beam end. This ensures that the bearing capacity of the node area is higher than that of the adjacent precast beam, thereby controlling the plastic hinge to appear only in the target precast beam end area, and not in the node area. Alternatively, when the node area is separated from the column side, the additional lapped connection steel bars on the column side and the extended lapped longitudinal bars at the beam end are configured in one of the following ways: the number of steel bars on the column side is less than the number of steel bars at the beam end; a single layer of steel bars is set on the column side while a double layer of steel bars is set at the beam end; or the diameter of the steel bars on the column side is smaller than the diameter of the steel bars at the beam end. This makes the bearing capacity of the node area higher than that of the adjacent precast extended section on the column side, so as to control the plastic hinge to appear only in the target precast extended section area, rather than in the node area.
5. The adjustable plastic hinge full-length column prefabricated frame structure according to claim 1, characterized in that... The concrete poured in the node area is concrete with a strength grade of not less than C40 or ECC material.
6. The adjustable plastic hinge full-length column prefabricated frame structure according to claim 1, characterized in that... The stirrups in the node area are densified.
7. The adjustable plastic hinge full-length column prefabricated frame structure according to claim 1, characterized in that... The connection interface between the side of the precast continuous column and the end of the precast beam is roughened manually.
8. The adjustable plastic hinge full-length column prefabricated frame structure according to claim 1, characterized in that... At the edge column node of the frame structure, one end of the additional lapped connection steel bar is bent and anchored inside the edge column at a 90-degree angle, the horizontal section length is not less than 0.4 times the basic seismic anchorage length and extends to the inside of the column longitudinal reinforcement, and the bent section length is not less than 15 times the steel bar diameter.
9. The adjustable plastic hinge full-length column prefabricated frame structure according to claim 1, characterized in that... The lap joints of the additional lapped reinforcing bars and the extended lapped longitudinal bars adopt a 90-degree hook structure or an end-welded anchor plate structure.
10. A construction method for a prefabricated frame structure with adjustable plastic hinges as described in claim 1, characterized in that... This includes the following steps: S1: Prefabricate the prefabricated continuous column and the prefabricated beam; S2: Hoisting the precast continuous column; S3: Hoist the precast beam, tie and lap the extended longitudinal reinforcement bars at the beam end to the additional lap reinforcement bars on the column side, and reinforce the joint area with additional stirrups; S4: Pour concrete in the node area.