A connection system for buckling restrained braces and fabricated concrete frame structures

Abstract

The utility model discloses a kind of for buckling-restrained brace (BRB) and the connecting system of fabricated concrete frame structure. The system includes concrete frame unit by superimposed beam and prefabricated column assembly, by steel beam, steel column, buckling-restrained brace and node plate constitute embedded steel support frame unit, and integral connecting unit cast-in-place concrete belt. Two frame units are integrative lateral force resisting structure by cast-in-place concrete belt pouring connection. Among them, anchoring steel bar in concrete frame, reserved anchoring and bolt in steel frame are anchored in cast-in-place concrete belt. The system optimizes traditional point connection to integral surface connection, significantly improves the integrity of structure, collaborative stress performance and seismic capacity, simultaneously realizes component factory prefabrication and on-site efficient assembly, construction is convenient, precision is easy to control, especially applicable to the fabricated concrete frame structure of higher requirement to seismic performance.

Description

Technical Field

[0001] This utility model belongs to the field of energy dissipation and vibration reduction technology of prefabricated housing buildings, specifically a connection system for buckling restrained braces (BRBs) and prefabricated concrete frame structures. Background Technology

[0002] In recent years, with the increasing demands for industrialized and green development in my country's construction industry, and the promotion of relevant laws and policies such as the "Regulations on Seismic Management of Construction Projects," the combined application of prefabricated building structures and energy dissipation and vibration reduction technologies has become an important direction for the development of the construction industry. Prefabricated concrete frame structures are widely used due to their advantages such as high standardization of components, fast construction speed, and minimal on-site wet work. Meanwhile, buckling-restrained braces (BRBs), as a highly efficient energy dissipation and vibration reduction component, have clearly defined stiffness and bearing capacity, do not buckle under compression, and have stable energy dissipation capacity. They have already demonstrated their significant effect in improving the seismic performance of buildings in earthquake-prone areas.

[0003] However, existing connection technologies still face several significant challenges when applying buckling-restrained braces (BRBs) to precast concrete frame structures. Currently, technical solutions mainly fall into two categories: one is optimization in the field of pure steel structures, such as using parallel BRBs to improve the bearing capacity of a single brace (e.g., CN210316057U), but this type of solution does not solve the problem of efficient and reliable connection between the BRBs and the concrete frame; the other type involves setting embedded parts on precast concrete members and externally attaching BRB members through bolt connections or other methods (e.g., CN208965716U). While the latter achieves a certain degree of integration between damping components and prefabricated structures, its connection method is essentially a "point-type" mechanical connection, which has the following inherent drawbacks: First, the connection node is subjected to point stress, requiring extremely high precision in embedded parts and installation. Construction deviations can easily lead to stress concentration, affecting the reliability of the node. Second, the "point-type" connection between the buckling-restrained brace and the concrete frame means that its yield bearing capacity should not be too high; otherwise, the embedded parts and bolts will be too large, affecting the collaborative working ability with the main concrete frame and making it difficult to fully utilize the potential of both to resist lateral displacement, thus creating a bottleneck in improving the overall structural stiffness and energy dissipation capacity. Finally, this post-connection method increases the procedures and difficulty of on-site high-altitude operations, which deviates from the original intention of prefabricated buildings to pursue efficient and precise installation.

[0004] Therefore, existing technologies have failed to provide an integrated solution that enables buckling-restrained braces and prefabricated concrete frames to form a cohesive whole, facilitating easy construction and ensuring reliable connection. The industry urgently needs an innovative connection system to address the problem of insufficient lateral stiffness in prefabricated concrete frames and to fully leverage the energy dissipation advantages of buckling-restrained braces, thereby promoting the application of prefabricated energy dissipation and vibration reduction structures in buildings with higher fortification requirements and greater structural strength. Utility Model Content

[0005] The purpose of this invention is to overcome the problems in the existing technology, such as the lack of integral connection between buckling-restrained braces and prefabricated concrete frames, complex construction, and poor seismic synergy when the yield bearing capacity is large. It provides a connection system for buckling-restrained braces and prefabricated concrete frame structures that is structurally reasonable, easy to construct, has strong integrity, and has excellent seismic performance.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A connection system for buckling-restrained braces (BRBs) to prefabricated concrete frame structures includes prefabricated concrete frame units, embedded steel bracing frame units, and integral connection units.

[0007] The prefabricated concrete frame unit is assembled from upper and lower composite beams and precast columns connecting the two. A steel sleeve is pre-embedded at the bottom of the upper composite beam, and the lower end of the steel sleeve is mechanically connected to a downwardly extending anchoring bar; a pre-embedded upwardly extending reserved anchor bar is pre-embedded at the top of the lower composite beam. Keyways are pre-fabricated on the sides of the precast columns, and "U"-shaped anchor bars are pre-embedded therein.

[0008] The embedded steel support frame unit includes upper and lower steel beams, left and right steel columns, buckling-restrained braces, and upper and lower node plates connected to both ends of the buckling-restrained braces, respectively. The steel columns are prefabricated in the factory as upper and lower sections, with bolt holes pre-drilled at the splicing ends. The upper and lower steel beams are welded to the corresponding steel column sections in the factory to form sub-steel frames, which are then connected on-site to form a complete steel frame using splicing plates and bolts. The upper node plate is located in the middle of the upper steel beam and welded to it. There are two lower node plates, located at the bottom corners of the frame formed by the connection between the lower steel beam and the two side steel columns, and welded to the lower steel beam and steel columns respectively. Vertical uprights of the upper node plate are welded perpendicularly to the left, right, front, and rear edges, with an upper node plate capping plate welded to its lower end. Vertical uprights of the lower node plate are welded perpendicularly to the left or right and upper edges. Steel beam stiffening ribs are welded at corresponding positions on the upper steel beam and the vertical plate of the upper node plate. Steel beam stiffening ribs and steel column stiffening ribs are also welded at corresponding positions on the lower steel beam and the vertical plate of the lower node plate, respectively. The upper end of the buckling-restrained brace is welded to the upper node plate via an upper diagonal stiffening plate, and the lower end is welded to the lower node plate via a lower diagonal stiffening plate, forming an embedded steel bracing frame unit with the overall steel frame. Multiple studs are welded to the outer flanges of the steel beams and columns.

[0009] The integral connection unit is a cast-in-place concrete strip, in which longitudinal reinforcement and stirrups are tied. The anchoring reinforcement, reserved anchor bars, "U"-shaped anchor bars, and studs on the steel beams and columns all extend into and are anchored within this concrete strip. The concrete strip is continuously poured, simultaneously wrapping and connecting the following areas: between the bottom of the upper composite beam and the top of the upper steel beam, between the top of the lower composite beam and the bottom of the lower steel beam, and between the side of the precast column and the adjacent steel column.

[0010] The prefabricated concrete frame unit and the embedded steel support frame unit are arranged in parallel to each other and are connected by integral connection unit to form an integrated lateral force resisting structure, realizing surface force transmission and overall collaborative work.

[0011] Compared with the prior art, the present invention has the following beneficial effects: By tightly connecting the prefabricated concrete frame with the embedded steel bracing frame through an integral cast-in-place concrete strip, the traditional "point connection" has been transformed into an improved "surface connection," significantly enhancing the overall integrity and synergistic seismic resistance of the structure. Simultaneously, the prefabricated frame and steel frame can be prefabricated separately, assembled on-site, and then uniformly cast, resulting in clear construction procedures and high installation precision, effectively reducing the difficulty and errors associated with high-altitude welding and post-connection work. Node plates are placed at key locations such as the middle of the steel beams and the bottom corners of the frame, supplemented by vertical plates, end plates, stiffening ribs, and diagonal stiffening plates for multiple reinforcements, ensuring the reliability of the buckling-restrained brace end connections and the clarity of force flow transmission. This system fully leverages the respective advantages of prefabricated concrete and buckling-restrained braces, not only significantly improving the lateral stiffness and energy dissipation capacity of the structure but also broadening the application range of prefabricated concrete frames in high-intensity seismic zones and high-rise buildings, exhibiting excellent comprehensive seismic performance and significant construction efficiency advantages. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 yes Figure 1 Schematic diagram of on-site splicing of steel columns in a central integrated steel frame; Figure 3 yes Figure 1 Schematic diagram of the connection between the upper and lower node plates; Figure 4 yes Figure 1 Schematic diagram of the connection between the upper and middle composite beams and the upper steel beam; Figure 5 yes Figure 1 Schematic diagram of the connection between the middle and lower composite beams and the lower steel beam; Figure 6 yes Figure 1 Schematic diagram of the connection between precast columns and steel columns.

[0013] In the diagram: 1-Composite beam, 2-Precast column, 3-Buckling restraint brace, 4-Steel column, 5-Steel beam, 6-Upper gusset plate, 7-Lower gusset plate, 8-Cast-in-place concrete strip, 11-Steel sleeve, 12-Anchor reinforcement, 13-Reserved anchor bar, 21-“U”-shaped anchor bar, 22-Keyway, 31-Upper diagonal stiffening plate, 32-Lower diagonal stiffening plate, 41-First stud, 42-Steel column stiffening rib, 43-Steel column splice plate, 44-Steel column splice bolt, 51-Second stud, 52-Steel beam stiffening rib, 61-Upper gusset plate vertical plate, 62-Upper gusset plate capping plate, 71-Lower gusset plate vertical plate, 81-Longitudinal reinforcement, 82-Stirrup. Detailed Implementation

[0014] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the technical solution and implementation process of the present invention.

[0015] like Figure 1 As shown, a connection system for buckling-restrained braces (BRBs) and prefabricated concrete frame structures mainly consists of three parts: prefabricated concrete frame units, embedded steel bracing frame units, and integral connection units.

[0016] The prefabricated concrete frame unit includes upper and lower composite beams 1 and precast columns 2 connecting the upper and lower composite beams. The composite beams 1 and precast columns 2 are prefabricated in the factory and then transported to the site for assembly into a frame. For example... Figure 4 As shown, a steel sleeve 11 is pre-embedded at the bottom of the upper composite beam, and the lower end of the steel sleeve 11 is fixed with a downwardly extending anchoring steel bar 12 by a mechanical connection; as Figure 5 As shown, the top of the lower composite beam has pre-embedded anchor bars 13 extending upwards. Figure 6 As shown, the side of the precast column 2 is precast with a keyway 22 and a U-shaped anchor bar 21 is pre-embedded, and the open end of the U-shaped anchor bar 21 faces the precast area of ​​the precast column.

[0017] The embedded steel-braced frame unit includes vertically arranged steel beams 5, horizontally arranged steel columns 4, buckling-restrained braces 3, and upper and lower gusset plates 6 and 7 respectively connected to the two ends of the buckling-restrained braces. For example... Figure 2 As shown, the steel column 4 is prefabricated in the factory as upper and lower sections, and the steel beam 5 is also divided into upper and lower steel beams. Both are welded to the corresponding steel column 4 in the factory to form upper and lower sub-steel frames. Then, they are assembled on site into a whole steel frame using splicing plates 43 and splicing bolts 44.

[0018] like Figure 3As shown, the upper node plate 6 is located in the middle of the upper steel beam and welded to it. The upper node plate 6 is trapezoidal, with vertical upright plates 61 welded vertically to its left, right, front, and rear edges, and an upper node plate sealing plate 62 welded to its lower end. There are two lower node plates 7, which are respectively located at the bottom corners of the frame formed by the connection between the lower steel beam and the two side steel columns 4, and are welded to the lower steel beam and the steel columns respectively. The lower node plate 7 is also trapezoidal, with vertical upright plates 71 welded vertically to its left or right and upper edges.

[0019] To further enhance the stiffness of the nodes, steel beam stiffening ribs 52 are welded at the positions corresponding to the vertical plates 61 of the upper steel beams and the upper node plates; steel beam stiffening ribs 52 and steel column stiffening ribs 42 are welded at the positions corresponding to the vertical plates 71 of the lower steel beams and the lower steel columns 4.

[0020] The upper end of the buckling restraint brace 3 is welded to the upper node plate 6 and the upper node plate vertical plate 61 via the upper diagonal stiffening plate 31; its lower end is welded to the lower node plate 7 and the lower node plate vertical plate 71 via the lower diagonal stiffening plate 32, thereby forming a stable embedded steel support frame unit.

[0021] like Figure 4-6 As shown, a second stud 51 is welded to the outer flange of the steel beam 5, and a first stud 41 is welded to the outer flange of the steel column 4. These studs will be embedded in the concrete during the subsequent pouring process to enhance the connection performance of the steel-concrete interface.

[0022] The integral connection unit is a cast-in-place concrete strip 8, in which longitudinal reinforcement bars 81 and stirrups 82 are tied. During construction, the longitudinal reinforcement bars 81 and stirrups 82 are tied in the gap between the prefabricated concrete frame unit and the embedded steel support frame unit. Formwork is erected on the sides of the gap, and then non-shrink concrete is poured to form an integral cast-in-place concrete strip 8. Anchor bars 12, reserved anchor bars 13, U-shaped anchor bars 21, and first studs 41 and second studs 51 all extend into and are anchored in the cast-in-place concrete strip 8.

[0023] The cast-in-place concrete strip 8 is continuously poured and simultaneously encloses the following three areas: between the bottom of the upper composite beam and the top of the upper steel beam, between the top of the lower composite beam and the bottom of the lower steel beam, and between the side of the precast column 2 and the adjacent steel column 4. Through this cast-in-place concrete strip 8, the prefabricated concrete frame unit and the embedded steel support frame unit are connected into an integrated lateral force resisting structure, realizing surface force transfer and overall collaborative work.

[0024] The implementation process of this utility model mainly includes factory prefabrication, on-site assembly of concrete frames, assembly of sub-steel frames, welding of joints and buckling restraint braces to form an internal support frame, hoisting and positioning, tying of reinforcing bars, and formwork and pouring of concrete strips. The construction logic is clear and easy to control the quality, ultimately forming a composite structural system with superior overall performance and strong seismic resistance.

[0025] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A connection system for buckling-restrained braces and prefabricated concrete frame structures, characterized in that, include: The prefabricated concrete frame unit is assembled from the upper and lower composite beams (1) and the prefabricated columns (2) connecting the upper and lower composite beams; The embedded steel support frame unit includes steel beams (5) arranged vertically, steel columns (4) arranged horizontally, buckling restraint braces (3), and upper node plates (6) and lower node plates (7) respectively connected to the two ends of the buckling restraint braces. The integral connection unit is a cast-in-place concrete strip (8), in which longitudinal bars (81) and stirrups (82) are tied; wherein, the prefabricated concrete frame unit and the embedded steel support frame unit are arranged in parallel to each other, and are connected by the integral connection unit to form an integrated lateral force resisting structure.

2. The connection system according to claim 1, characterized in that: In the composite beam (1), a steel sleeve (11) is pre-embedded at the bottom of the upper composite beam, and the lower end of the steel sleeve (11) is fixed with a downwardly extending anchoring bar (12) by mechanical connection; a reserved anchor bar (13) is pre-embedded at the top of the lower composite beam, and the free end of the anchoring bar (12) and the free end of the reserved anchor bar (13) both extend into and are anchored in the cast-in-place concrete strip (8).

3. The connection system according to claim 1, characterized in that: The precast column (2) has multiple keyways (22) precast at equal intervals on its side and has "U"-shaped anchor bars (21) pre-embedded; the open end of the "U"-shaped anchor bar (21) extends into and is anchored in the cast-in-place concrete strip (8).

4. The connection system according to claim 1, characterized in that: The steel column (4) is prefabricated in the factory into upper and lower sections, and bolt holes are reserved at the splicing end. The upper and lower steel beams (5) are each welded to the corresponding steel column sections in the factory to form upper and lower sub-steel frames. Then, they are assembled on site into an integral steel frame by splicing plates (43) and splicing bolts (44).

5. The connection system according to claim 1, characterized in that: The upper node plate (6) is set in the middle of the upper steel beam in the steel beam (5) and welded to it; The lower node plate (7) consists of two parts, which are respectively set at the bottom corner of the sub-steel frame formed by the connection of the lower steel beam and the steel columns (4) on both sides, and are respectively welded and fixed to the corresponding lower steel beam and steel column; The upper node plate (6) has vertical upright plates (61) welded vertically to the left, right, front and rear edges, and upper node plate sealing plates (62) welded to its lower end. The lower node plate (7) has a vertical support plate (71) welded vertically to its left or right side and upper edge.

6. The connection system according to claim 1, characterized in that: In the steel beam (5), the upper steel beam is welded with steel beam stiffening ribs (52) at the position corresponding to the vertical plate (61) of each upper node plate; the lower steel beam and steel column (4) are welded with steel beam stiffening ribs (52) and steel column stiffening ribs (42) at the position corresponding to the vertical plate (71) of each lower node plate.

7. The connection system according to claim 1, characterized in that: The upper end of the buckling restraint brace (3) is fixedly connected to the upper node plate (6) through the upper diagonal stiffening plate (31); the lower end is welded to the lower node plate (7) through the lower diagonal stiffening plate (32), forming a complete embedded steel support frame unit with the overall steel frame.

8. The connection system according to claim 1, characterized in that: Multiple first studs (41) and second studs (51) are welded to the outer flange of the steel column (4) and the outer flange of the steel beam (5); the first studs (41) and the second studs (51) are embedded in the concrete strip (8).

9. The connection system according to any one of claims 1-8, characterized in that: The cast-in-place concrete strip (8) is a continuously cast, non-shrink concrete body that simultaneously wraps and connects: the area between the bottom of the upper composite beam and the top of the upper steel beam, the area between the top of the lower composite beam and the bottom of the lower steel beam, and the area between the side of the precast column and the adjacent steel column; thereby enabling the prefabricated concrete frame unit and the embedded steel support frame unit to achieve surface force transmission and overall collaborative work.

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