A hanging box-type connection structure between a connecting column and a composite beam steel box and a construction method thereof

Abstract

The present invention discloses a steel box-underhanging box-type connection structure for connecting columns and composite beams and a construction method. The structure comprises: an upper prefabricated and assembled hollow concrete column, a middle prefabricated and assembled hollow concrete column, a lower prefabricated and assembled hollow concrete column, and a precast concrete composite beam. The precast concrete beam has a groove at the bottom of the beam on one side near the middle prefabricated and assembled hollow concrete column. A steel box A is embedded in the groove. A steel box B is fixed below steel box A. The side surface of steel box B contacts the middle prefabricated and assembled hollow concrete column, and the top surface contacts steel box A. The steel box-underhanging box-type connection structure for connecting columns and composite beams and the construction method provided by the present invention have the advantages of simple assembly, wide application, good seismic performance, full utilization of reinforcement strength, high restraint effect, and simple construction steps.

Description

Technical Field

[0001] The present invention belongs to the technical field of civil engineering, and in particular relates to a steel box under-hanging box-type connection structure for connecting columns and composite beams and a construction method. Background Art

[0002] Compared to traditional cast-in-place concrete production, prefabricated construction reduces wet work on the construction site, saving time and materials. In recent years, prefabricated construction has experienced rapid growth in my country. Prefabricated beam-column and column-column joint connections are key technologies in prefabricated building construction.

[0003] At present, the existing dry node connection structures proposed for the beam-column and column-column connections of prefabricated concrete frame structures mainly include bolt connection, welding connection, steel hanger connection and corbel connection. These four connection methods all have some defects to varying degrees: ① The plastic development of bolt connection nodes is relatively fast, the residual deformation is large, and it is difficult to achieve self-reset. It is difficult to disassemble and replace the nodes after damage, and it is difficult to achieve rapid recovery of structural functions; ② Welding connections have poor seismic performance because they do not have plastic hinges; ③ Steel hanger connection components are numerous, the structure is complex, and high installation accuracy is required; ④ Corbel connection, as a more commonly used node connection method, is divided into open corbel connection and concealed corbel connection. The open corbel connection occupies a large space and is not beautiful because the exposed corbel occupies a large space, while the concealed corbel connection will inevitably affect the mechanical properties of the components due to considerations of aesthetics. At the same time, the reinforcement of the beam end and the corbel is relatively complicated.

[0004] In summary, researching and developing a connection method that is simple to assemble, has a wide range of applications, has good seismic performance, and simplifies construction steps is of great significance to the development of prefabricated buildings. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a box-type connection structure and construction method for connecting columns and composite beams with steel boxes. The technical problems to be solved by the present invention are achieved through the following technical solutions:

[0006] A steel box under-hanging box-type connection structure connecting columns and composite beams, comprising: an upper prefabricated assembled hollow concrete column, a middle prefabricated assembled hollow concrete column, a lower prefabricated assembled hollow concrete column and a prefabricated concrete composite beam, wherein:

[0007] The upper prefabricated assembled hollow concrete column is fixedly connected to the upper end of the middle prefabricated assembled hollow concrete column, and the lower prefabricated assembled hollow concrete column is fixedly connected to the lower end of the middle prefabricated assembled hollow concrete column;

[0008] A first transverse dowel and a second transverse dowel are transversely arranged in the middle of the middle prefabricated assembled hollow concrete column, and the lengths of the first transverse dowel and the second transverse dowel are wider than the width of the middle prefabricated assembled hollow concrete column;

[0009] The precast concrete beam has a groove at the bottom of one side of the beam close to the middle precast assembled hollow concrete column, and a steel box A is embedded in the groove. The steel box A includes a first connecting member and a second connecting member. The first connecting member is a double "mouth" shape connected together in parallel, and its bottom is not closed. The side contacting the middle precast assembled hollow concrete column has two U-shaped openings opening downward, and the opposite side is fixed with the second connecting member, which is a U-shaped groove opening upward;

[0010] A steel box B is fixed under the steel box A, and the side surface of the steel box B contacts the middle prefabricated assembled hollow concrete column, and the top surface contacts the steel box A;

[0011] The lower prestressed longitudinal reinforcement of the precast concrete beam extends into the U-shaped groove of the second connecting piece, the first transverse dowel is inserted into the U-shaped opening of the first connecting piece, and the second transverse dowel is inserted into the side of the steel box B, thereby realizing a vertical fixed connection between the precast concrete beam and the middle precast assembled hollow concrete column.

[0012] In one embodiment of the present invention, the upper prefabricated assembled hollow concrete column is provided with upper column longitudinal reinforcement, and an upper central hole is prefabricated at the axis; the lower prefabricated assembled hollow concrete column is provided with lower column longitudinal reinforcement, and a lower central hole is prefabricated at the axis;

[0013] The four corners of the central prefabricated assembled hollow concrete column are prefabricated with reserved holes, and a pre-buried steel pipe is set at the axis, and the two ends of the pre-buried steel pipe extend out of the upper and lower end surfaces of the concrete of the central prefabricated assembled hollow concrete column;

[0014] The upper column longitudinal reinforcement and the lower column longitudinal reinforcement are inserted into the reserved holes, and the two ends of the embedded steel pipe are respectively inserted into the upper center hole and the lower center hole, so as to realize the fixed connection of the upper prefabricated assembled hollow concrete column, the middle prefabricated assembled hollow concrete column and the lower prefabricated assembled hollow concrete column.

[0015] In one embodiment of the present invention, the upper column longitudinal reinforcement is arranged at the four corners of the upper prefabricated assembled hollow concrete column, and the portion located at the lower end of the upper prefabricated assembled hollow concrete column is bent inward and extends longitudinally from the lower bottom surface of the upper prefabricated assembled hollow concrete column; a plurality of groups of upper column stirrups are transversely arranged around the outer periphery of the upper column longitudinal reinforcement in the upper prefabricated assembled hollow concrete column.

[0016] In one embodiment of the present invention, the lower column longitudinal reinforcement is arranged at the four corners of the lower prefabricated assembled hollow concrete column, and the portion located at the upper end of the lower prefabricated assembled hollow concrete column is bent inward and extends longitudinally from the upper surface of the upper prefabricated assembled hollow concrete column; a plurality of groups of lower column stirrups are transversely arranged around the outer periphery of the lower column longitudinal reinforcement in the lower prefabricated assembled hollow concrete column.

[0017] In one embodiment of the present invention, longitudinal reinforcement steel bars are further provided at the four corners of the central prefabricated assembled hollow concrete column, and the longitudinal reinforcement steel bars are provided on the outside of the reserved holes; center column stirrups are fixed outside the longitudinal reinforcement steel bars.

[0018] In one embodiment of the present invention, the precast concrete beam is provided with upper prestressed longitudinal bars A, upper prestressed longitudinal bars B, and lower prestressed longitudinal bars. The upper prestressed longitudinal bars A and the upper prestressed longitudinal bars B are horizontally arranged at the upper end of the precast concrete beam, and the upper prestressed longitudinal bars A and the upper prestressed longitudinal bars B are connected by a steel sleeve; the upper prestressed longitudinal bars A are inserted into the middle precast assembled hollow concrete column.

[0019] In one embodiment of the present invention, the upper end surface of the concrete of the central prefabricated assembled hollow concrete column is provided with reserved openings on both sides, and the upper prestressed longitudinal reinforcement A is inserted into the reserved openings and fixed by pouring concrete.

[0020] In one embodiment of the present invention, the upper prestressed longitudinal reinforcement B and the lower prestressed longitudinal reinforcement are fixed by middle column stirrups, and the upper prestressed longitudinal reinforcement A and the lower prestressed longitudinal reinforcement are fixed by open stirrups. The upper end of the open stirrup has an opening, and two ends are bent downward to fix the upper prestressed longitudinal reinforcement A.

[0021] In one embodiment of the present invention, the precast concrete beam is further provided with bent ribs, which are arranged at the lower part of the precast concrete beam and correspond to the lower position of the upper prestressed longitudinal reinforcement A; a part of the bent rib is arranged on the open stirrups on the steel box A, and the other part penetrates into the bottom of the precast concrete beam and is fixed under the open stirrups at the lower prestressed longitudinal reinforcement.

[0022] A construction method of the above-mentioned box-type connection structure of the connecting column and the composite beam steel box hanging below, comprising the steps of:

[0023] (1) Prefabricate the required upper prefabricated assembled hollow concrete columns, middle prefabricated assembled hollow concrete columns, lower prefabricated assembled hollow concrete columns and concrete composite beams;

[0024] (2) hoisting the middle prefabricated assembled hollow concrete column above the lower prefabricated assembled hollow concrete column, so that the lower column longitudinal reinforcement extending from the lower prefabricated assembled hollow concrete column passes through the reserved hole of the middle prefabricated assembled hollow concrete column, and the embedded steel pipe of the middle prefabricated assembled hollow concrete column is inserted into the lower hollow hole of the lower prefabricated assembled hollow concrete column;

[0025] (3) inserting the upper prestressed longitudinal reinforcement A of the precast concrete composite beam through the reserved opening of the middle precast assembled hollow concrete column into the reserved hole at the far end of the middle precast assembled hollow concrete column so as to be tied with the upper column longitudinal reinforcement inserted into the reserved hole, and then installing the steel box B at the second transverse dowel of the middle precast assembled hollow concrete column;

[0026] (4) hoisting the precast concrete composite beam to the corresponding position, passing the first transverse dowel bar through the U-shaped opening on one side of the steel box A embedded in the precast concrete composite beam, and fixing it with bolts; connecting the upper prestressed longitudinal reinforcement A and the upper prestressed longitudinal reinforcement B with a steel sleeve;

[0027] (5) hoisting the upper prefabricated assembled hollow concrete column to the top of the middle prefabricated assembled hollow concrete column, so that the upper column longitudinal reinforcement extending from the upper prefabricated assembled hollow concrete column is inserted into the reserved holes at the four corners of the middle prefabricated assembled hollow concrete column, and the embedded steel pipe of the middle prefabricated assembled hollow concrete column is inserted into the upper hollow hole of the upper prefabricated assembled hollow concrete column;

[0028] (6) pouring high-strength shrinkage compensation mortar into the reserved holes at the four corners of the middle prefabricated assembled hollow concrete column;

[0029] (7) completely hoisting the upper prefabricated assembled hollow concrete column onto the middle prefabricated assembled hollow concrete column;

[0030] (8) Hoist the composite slab onto the precast concrete composite beam, pour concrete, and complete the construction.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The column-beam connection of the present invention is connected to the steel box A and the steel box B respectively through the first transverse dowel and the second transverse dowel, and is connected to the column through the upper prestressed longitudinal reinforcement A. When a major earthquake occurs, it can meet the design concept of "strong node, weak member", control the occurrence of plastic hinges at the node position, and yield through the energy consumption of the node to achieve the effect of shock absorption, while facilitating post-earthquake repair and replacement.

[0033] (2) The column-column connection of the present invention is achieved by setting reserved holes at the four corners of the prefabricated assembled hollow concrete column in the middle, and setting spiral stirrups in the reserved holes. The spiral stirrups at the four corners can have a strong restraining effect on the corner concrete, provide an effective restraining effect, and increase the ductility of the concrete, effectively ensuring the seismic performance of the column; by setting longitudinal reinforcement steel bars at the four corners and setting them in the restraining area of the spiral stirrups, and other longitudinal reinforcements are set at the edge of the column, these reinforcements can increase the bearing capacity of the column; by using the middle column stirrups to ensure shear strength, and the middle column stirrup scheme and arrangement are simple, and will not cause manufacturing difficulties; by setting embedded steel pipes in the prefabricated assembled hollow concrete column in the middle, the shear performance of the column-column connection can be effectively enhanced.

[0034] (3) The beams and columns of the present invention are all prefabricated. Under the premise that the connection method can meet the performance of the building such as stability and bearing capacity, wet work on the construction site is reduced, and the installation is convenient and the process is simple, which can save construction time.

[0035] (4) The specific structural design and specific connection method of the present invention are combined together, and the technical effects of various design points are superimposed, so that the constructed box-type connection structure of the connecting column and the composite beam steel box hanging below has stronger stability, bearing capacity, shear resistance and seismic resistance.

[0036] (5) The box-type connection structure and construction method of the connecting column and the composite beam steel box provided by the present invention have the advantages of simple assembly, wide application, good seismic performance, full utilization of reinforcement strength, high constraint effect, and simple construction steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of a box-type connection structure of a connection column and a composite beam steel box under the embodiment of the present invention;

[0038] Figure 2 This is a schematic diagram of an upper prefabricated assembled hollow concrete column provided by an embodiment of the present invention;

[0039] Figure 3 Schematic diagram of a lower prefabricated assembled hollow concrete column provided by an embodiment of the present invention;

[0040] Figure 4 This is a schematic diagram of a central prefabricated assembled hollow concrete column provided by an embodiment of the present invention;

[0041] Figure 5 Schematic diagram of a precast concrete composite beam provided by an embodiment of the present invention;

[0042] Figure 6 This is a schematic diagram of the structure of a steel box A provided by an embodiment of the present invention. Figure 1 ;

[0043] Figure 7 This is a schematic diagram of the structure of a steel box A provided by an embodiment of the present invention. Figure 2 ;

[0044] Figure 8 1 is a structural diagram of a steel box B provided in an embodiment of the present invention;

[0045] Figure 9 It is a schematic diagram of the connection relationship between the upper prestressed longitudinal reinforcement A and the middle prefabricated assembled hollow concrete column provided by an embodiment of the present invention.

[0046] Figure 1: 1-upper prefabricated hollow concrete column; 2-middle prefabricated hollow concrete column; 3-lower prefabricated hollow concrete column; 4-precast concrete composite beam; 5-upper column longitudinal reinforcement; 6-upper center hole; 7-upper column stirrups; 8-lower column longitudinal reinforcement; 9-lower center hole; 10-lower column stirrups; 11-reserved hole; 12-embedded steel pipe; 13-spiral stirrups; 14-longitudinal reinforcement steel bar; 15-middle column stirrups; 16 -First transverse dowel; 17-Second transverse dowel; 18-Steel box A; 19-First connecting piece; 20-Second connecting piece; 21-High-strength bolt; 22-Side plate; 23-Right-angle triangle plate; 24-Upper prestressed longitudinal reinforcement A; 25-Upper prestressed longitudinal reinforcement B; 26-Lower prestressed longitudinal reinforcement; 27-Rebar sleeve; 28-Reserved opening; 29-Open stirrups; 30-Bent reinforcement; 31-Horizontal opening; 32-Broken line opening; 33-Steel box B. DETAILED DESCRIPTION

[0047] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0048] See Figure 1 , Figure 1Schematic diagram of a steel box-mounted box-type connection structure between a connecting column and a composite beam provided in an embodiment of the present invention. The steel box-mounted box-type connection structure between a connecting column and a composite beam provided in an embodiment of the present invention comprises: an upper prefabricated hollow concrete column 1, a middle prefabricated hollow concrete column 2, a lower prefabricated hollow concrete column 3, and a precast concrete composite beam 4. The upper prefabricated hollow concrete column 1 is fixedly connected to the upper end of the middle prefabricated hollow concrete column 2, and the lower prefabricated hollow concrete column 3 is fixedly connected to the lower end of the middle prefabricated hollow concrete column 2. The precast concrete composite beam 4 is vertically fixedly connected to the middle prefabricated hollow concrete column 2. The upper prefabricated assembled hollow concrete column, the middle prefabricated assembled hollow concrete column 2, the lower prefabricated assembled hollow concrete column 3 and the prefabricated concrete composite beam 4 involved in the present invention all need to be prefabricated in advance. The hollow reinforced concrete columns used in all of them have light weight, save materials, have good cross-sectional expansion, are easy to install and lift, and save costs.

[0049] The specific structure and connection relationship of each part are described in detail below.

[0050] See Figure 2 , Figure 2 This is a schematic diagram of an upper prefabricated assembled hollow concrete column 1 provided by an embodiment of the present invention; as a preferred embodiment, the upper prefabricated assembled hollow concrete column 1 is provided with upper column longitudinal reinforcement 5, and an upper center hole 6 is prefabricated at the axis. Furthermore, there are four upper column longitudinal reinforcements 5, which are respectively arranged at the four corners of the upper prefabricated assembled hollow concrete column 1, and the portion located at the lower end of the upper prefabricated assembled hollow concrete column 1 is bent inward and extends longitudinally from the lower bottom surface of the upper prefabricated assembled hollow concrete column 1. Multiple groups of upper column stirrups 7 are arranged transversely around the outer periphery of the upper column longitudinal reinforcement 5 in the upper prefabricated assembled hollow concrete column 1.

[0051] See Figure 3 , Figure 3 This is a schematic diagram of a lower prefabricated assembled hollow concrete column 3 provided by an embodiment of the present invention; as a preferred embodiment, the lower prefabricated assembled hollow concrete column 3 is provided with lower column longitudinal reinforcement 8, and a lower center hole 9 is prefabricated at the axis. Furthermore, the lower column longitudinal reinforcement 8 is provided at the four corners of the lower prefabricated assembled hollow concrete column 3, and the portion located at the upper end of the lower prefabricated assembled hollow concrete column 3 is bent inward and extends longitudinally from the upper surface of the concrete of the lower prefabricated assembled hollow concrete column 3. Multiple groups of lower column stirrups 10 are transversely provided on the outer periphery of the lower column longitudinal reinforcement 8 in the lower prefabricated assembled hollow concrete column 3.

[0052] See Figure 4 , Figure 4This is a schematic diagram of a central prefabricated assembled hollow concrete column 2 provided in an embodiment of the present invention; the four corners of the central prefabricated assembled hollow concrete column 2 are prefabricated with reserved holes, and a pre-buried steel pipe 12 is provided at the axis, and the two ends of the pre-buried steel pipe 12 extend out of the upper and lower end surfaces of the concrete of the central prefabricated assembled hollow concrete column 2. It can be understood that a hollow hole is also prefabricated at the axis of the central prefabricated assembled hollow concrete column 2, and the pre-buried steel pipe 12 is provided in the hollow hole. In addition, the diameters of the upper center hole 6 and the lower center hole 9 are the same, and the diameter of the pre-buried steel pipe 12 is smaller than the diameters of the upper center hole 6 and the lower center hole 9, so that it can be inserted into the upper center hole 6 and the lower center hole 9 to connect the upper prefabricated assembled hollow concrete column 1, the central prefabricated assembled hollow concrete column 2 and the lower prefabricated assembled hollow concrete column 3. By arranging the embedded steel pipe 12 in the middle prefabricated column, the shear resistance of the column-column connection can be effectively enhanced.

[0053] In addition, the upper column longitudinal reinforcement 5 and the lower column longitudinal reinforcement 8 are inserted into the reserved holes, and the two ends of the embedded steel pipe 12 are respectively inserted into the upper center hole 6 and the lower center hole 9, thereby realizing the fixed connection of the upper prefabricated assembled hollow concrete column 1, the middle prefabricated assembled hollow concrete column 2 and the lower prefabricated assembled hollow concrete column 3.

[0054] In one embodiment, spiral stirrups 13 are installed in each reserved hole of the central prefabricated hollow concrete column 2. The spiral stirrups 13 at the four corners can exert a strong restraining effect on the corner concrete, provide an effective restraint effect, increase the ductility of the concrete, and effectively ensure the seismic performance of the column.

[0055] Furthermore, longitudinal reinforcement bars 14 are provided at the four corners of the central prefabricated assembled hollow concrete column 2, and the longitudinal reinforcement bars 14 are arranged outside the reserved holes; center column stirrups 15 are fixed outside the longitudinal reinforcement bars 14, and the center column stirrups 15 can be multiple groups of center column stirrups 15. By arranging longitudinal reinforcement bars 14 at the four corners and arranging them within the constraint area of the spiral stirrups 13, and other longitudinal reinforcements are arranged at the edges of the column, these reinforcements can increase the load-bearing capacity of the column. By adopting the center column stirrups 15, shear strength is guaranteed, and the design and arrangement of the center column stirrups 15 are simple, which will not cause manufacturing difficulties.

[0056] Please continue to see Figure 4A first transverse dowel 16 and a second transverse dowel 17 are installed transversely in the middle of the central prefabricated hollow concrete column 2. The length of the first and second transverse dowels 16 and 17 is greater than the width of the central prefabricated hollow concrete column 2. The purpose of providing these first and second transverse dowels 16 and 17 is to increase the number of nodes connecting the column to the beam and improve seismic resistance. High-strength bolts 21 are used for these first and second transverse dowels, which offer the advantage of high strength and improved shear resistance.

[0057] See Figure 5 , Figure 5 It is a schematic diagram of a precast concrete composite beam 4 provided by an embodiment of the present invention; the precast concrete composite beam 4 of the embodiment of the present invention has a groove at the bottom of the beam on one side close to the central precast assembled hollow concrete column 2, and a steel box A18 is embedded in the groove. The steel box A18 includes a first connecting member 19 and a second connecting member 20. The first connecting member 19 is a double "mouth" shape connected together in parallel, and its bottom is not closed, specifically including a top surface, four side surfaces and a middle partition; two U-shaped openings opening downward are provided on the side contacting the central precast assembled hollow concrete column 2, and the two U-shaped openings are respectively arranged on both sides of the middle partition; the second connecting member 20 is fixed to the opposite side, and the second connecting member 20 is a U-shaped groove opening upward.

[0058] Specifically, see Figure 6 and Figure 7 , Figure 6 This is a schematic diagram of the structure of a steel box A18 provided by an embodiment of the present invention. Figure 1 , Figure 7 This is a schematic diagram of the structure of a steel box A18 provided by an embodiment of the present invention. Figure 2 The upper surface of the first connector 19 of steel box A18 is provided with a plurality of high-strength bolts 21, preferably arranged in two rows of four bolts each. These bolts are embedded in the concrete to strengthen the connection between steel box A18 and the precast concrete composite beam 4. The upper right corner of steel box A18 is smoothly curved, effectively preventing localized damage at the contact point between steel box A18 and the beam concrete, thereby improving seismic resistance. The second connector 20 is a U-shaped groove with a flat bottom, which is fixedly connected to the first connector 19 and is preferably an integrated design.

[0059] See Figure 8 , Figure 8It is a structural schematic diagram of a steel box B33 provided by an embodiment of the present invention; the steel box B33 is fixed below the steel box A18, the side surface of the steel box B33 contacts the middle prefabricated assembled hollow concrete column 2, and the top surface contacts the steel box A18. Specifically, the steel box B33 includes a side plate 22 and three right-angled triangular plates 23 perpendicular to the side plate 22, one right-angled side of each right-angled triangular plate 23 is fixed to the side plate 22, and the other right-angled side contacts the bottom side corresponding to the first connecting member 19; bolt holes are provided on the side plates 22 between the two right-angled triangular plates 23 for the second transverse dowel to be inserted and fixed with bolts. The steel box B33 plays the role of supporting the steel box A18, further improving the seismic resistance.

[0060] Please also see Figures 4 to 8 The lower prestressed longitudinal reinforcement 26 of the precast concrete beam in the embodiment of the present invention extends into the U-shaped groove of the second connecting member 20, the first transverse dowel 16 is inserted into the U-shaped opening of the first connecting member 19, and the second transverse dowel 17 is inserted into the side of the steel box B33, thereby realizing a vertical fixed connection between the precast concrete beam and the middle prefabricated assembled hollow concrete column 2. For example, the first transverse dowel 16 is inserted into the steel box A18 and then fixed with bolts, and a rubber gasket can be provided between the bolt and the steel box A18; the second transverse dowel 17 is inserted into the bolt hole of the steel box B33 and then fixed with bolts, and a rubber gasket can be provided between the bolt and the steel box B33. In the embodiment of the present invention, a rubber gasket is provided between the bolt and the steel box at the beam-column connection, which can reduce the extrusion damage at the bolt connection and improve the seismic performance and working performance at the node.

[0061] Specifically, the precast concrete beam is provided with upper prestressed longitudinal bars A24, upper prestressed longitudinal bars B25, and lower prestressed longitudinal bars 26. The upper prestressed longitudinal bars A24 and B25 are arranged horizontally at the upper end of the precast concrete beam and connected by a steel sleeve 27. The upper prestressed longitudinal bars A24 are inserted into the middle precast and assembled hollow concrete column 2. The specific insertion method can be that the upper end surface of the concrete of the middle precast and assembled hollow concrete column 2 has reserved openings 28 on both sides, and the upper prestressed longitudinal bars A24 are inserted into the reserved openings 28 and fixed by pouring concrete.

[0062] The upper prestressed longitudinal reinforcement B25 and the lower prestressed longitudinal reinforcement 26 are fixed by the stirrups on the beam, and the upper prestressed longitudinal reinforcement A24 and the lower prestressed longitudinal reinforcement 26 are fixed by the open stirrups 29. The upper end of the open stirrups 29 has an opening, and the two ends are bent downward to fix the upper prestressed longitudinal reinforcement A24.

[0063] The precast concrete beam is also provided with bent ribs 30, which are arranged at the lower part of the precast concrete beam and correspond to the lower position of the upper prestressed longitudinal reinforcement A24; part of the bent rib 30 is arranged on the open stirrup 29 on the steel box A18, and the other part penetrates into the bottom of the precast concrete beam and is fixed under the open stirrup 29 at the lower prestressed longitudinal reinforcement 26.

[0064] By installing upper prestressed longitudinal bars A24, B25, lower prestressed longitudinal bars 26, and bent bars 30 in precast concrete beams, the present embodiment offers three advantages: 1. Reducing the tensile and bending stresses in the concrete above the beam; 2. Enhancing the crack resistance of the concrete; and 3. Prolonging the service life of the joint. Furthermore, by connecting the upper prestressed longitudinal bars A24 and B25 with a steel sleeve 27 and using open stirrups 29 for the upper prestressed longitudinal bars A24, any damage to the upper prestressed longitudinal bars A24 can be replaced.

[0065] See Figure 9 , Figure 9 This is a schematic diagram of the connection relationship between an upper prestressed longitudinal reinforcement A24 and a middle prefabricated assembled hollow concrete column 2 provided by an embodiment of the present invention; as a further embodiment, the reserved opening 28 of the middle prefabricated assembled hollow concrete column 2 includes a horizontal opening 31 and a broken line opening 32, wherein the horizontal opening 31 is perpendicular to the side surface and penetrates the side surface and the top surface, and the broken line opening 32 penetrates the top surface and is connected to the horizontal opening 31 at one end and to the reserved hole at the far end at the other end; after the upper prestressed longitudinal reinforcement A24 is inserted into the reserved opening 28, it passes through the horizontal opening 31 and the broken line opening 32 and is bent downward again before being inserted into the reserved hole at the far end so as to be tied with the lower column longitudinal reinforcement 8 inserted into the reserved hole. This design further improves the firmness and seismic resistance of the beam-column connection while ensuring that the upper prestressed longitudinal reinforcement A24 can be replaced. It should be noted that since both sides of the central prefabricated assembled hollow concrete column 2 are connected to prefabricated concrete beams, the upper prestressed longitudinal reinforcement A24 on both sides cross each other after entering the reserved opening 28 and enter the reserved holes at the far end, and are respectively tied to the upper and lower column longitudinal reinforcements 8 in the corresponding reserved holes, and finally fixed by pouring concrete.

[0066] The manufacturing method of each prefabricated component of the steel box under-hung box-type connection structure of the connecting column and the composite beam in the embodiment of the present invention is as follows:

[0067] 1. Precast concrete columns:

[0068] (a) Fabrication of the upper prefabricated hollow concrete column 1: First, formwork is supported and the upper column longitudinal reinforcement 5 and upper column stirrups 5 are fixed. The upper column longitudinal reinforcement 5 at the lower end of the column is bent inward and extends out of the lower bottom surface of the column to facilitate insertion into the reserved hole of the middle prefabricated column. Then, concrete is poured and cured to form the column. For details, see Figure 2.

[0069] (b) Production of the central prefabricated assembled hollow concrete column 2: First, formwork is supported, and reserved holes are left at the four corners of the cross section of the central prefabricated assembled hollow concrete column 2. Each reserved hole is constrained by spiral stirrups 13, and embedded steel pipes 12 are set at the axial hollow hole position. Longitudinal reinforcement steel bars 14 are set at the edge of the column, and middle column stirrups 15 are set outside the longitudinal reinforcement steel bars 14 to fix the steel cage. The prefabricated components of the central prefabricated assembled hollow concrete column 2 have the following special arrangements: ① The first transverse dowel 16 and the second transverse dowel 17 are placed in the middle and are slightly longer than the column width; ② During prefabrication, a reserved opening 28 is opened in the column to insert the upper prestressed steel bars A of the prefabricated beam; ③ A steel pipe is embedded at the axial hollow hole position, and the length allows it to extend into the upper and lower prefabricated columns respectively; ④ Reserved holes are prefabricated at the four corners of the column and spiral stirrups 13 are set in the reserved holes. Finally, the concrete is poured and cured to form, see for details. Figure 4 .

[0070] (c) Fabrication of the lower prefabricated hollow concrete column 3: First, formwork is supported and the lower column longitudinal reinforcement 8 and lower column stirrups 10 are fixed. The lower column longitudinal reinforcement 8 at the upper end of the column is bent inward and extends longitudinally beyond the upper surface of the column to facilitate insertion into the reserved holes at the four corners of the middle prefabricated column. Finally, concrete is poured and cured to form the column. For details, see Figure 3 .

[0071] 2. Precast concrete composite beam 4: A groove is provided at the bottom of the precast concrete beam on one side near the middle precast assembled hollow concrete column 2. A steel box A18 is embedded in the groove. Two longitudinal bars are provided at the top and bottom of the beam. Two bent steel bars are provided at the lower part of the beam to resist the shear force of the oblique section of the concrete at the steel box A18. A steel box B33 is provided under the steel box A18. Figure 5 .

[0072] The specific construction method of the steel box under-hung box-type connection structure of the connection column and the composite beam according to the embodiment of the present invention is as follows:

[0073] (1) Prefabricate the required upper prefabricated assembled hollow concrete column 1, middle prefabricated assembled hollow concrete column 2, lower prefabricated assembled hollow concrete column 3 and concrete composite beams;

[0074] (2) hoisting the middle prefabricated assembled hollow concrete column 2 above the lower prefabricated assembled hollow concrete column 3, so that the lower column longitudinal reinforcement 8 extending from the lower prefabricated assembled hollow concrete column 3 passes through the reserved hole of the middle prefabricated assembled hollow concrete column 2, and the embedded steel pipe 12 of the middle prefabricated assembled hollow concrete column 2 is inserted into the lower hollow hole of the lower prefabricated assembled hollow concrete column 3;

[0075] (3) Insert the upper prestressed longitudinal reinforcement A24 of the precast concrete composite beam 4 through the reserved opening 28 of the middle precast assembled hollow concrete column 2 and into the reserved hole at the far end of the middle precast assembled hollow concrete column 2 so as to be tied with the lower column longitudinal reinforcement 8 inserted into the reserved hole. Then, install the steel box B33 at the second transverse dowel 17 of the middle precast assembled hollow concrete column 2.

[0076] (4) Hoist the precast concrete composite beam 4 to the corresponding position, pass the first transverse dowel bar 16 through the U-shaped opening on one side of the steel box A18 embedded in the precast concrete composite beam 4, and fix it with bolts; connect the upper prestressed longitudinal reinforcement A24 and the upper prestressed longitudinal reinforcement B25 with the steel sleeve 27;

[0077] (5) Hoist the upper prefabricated assembled hollow concrete column 1 to the top of the middle prefabricated assembled hollow concrete column 2, so that the upper column longitudinal reinforcement 5 extending from the upper prefabricated assembled hollow concrete column 1 is inserted into the reserved holes at the four corners of the middle prefabricated assembled hollow concrete column 2, and the embedded steel pipe 12 of the middle prefabricated assembled hollow concrete column 2 is inserted into the upper hollow hole of the upper prefabricated assembled hollow concrete column 1;

[0078] (6) Pour high-strength shrinkage compensation mortar into the reserved holes at the four corners of the middle prefabricated assembled hollow concrete column 2;

[0079] (7) Completely hoist the upper prefabricated assembled hollow concrete column 1 onto the middle prefabricated assembled hollow concrete column 2;

[0080] (8) Hoist the composite slab onto the precast concrete composite beam 4, pour concrete, and complete the construction.

[0081] Compared with the prior art, the present invention has the following beneficial effects:

[0082] (1) The column-beam connection of the present invention is connected to the steel box A and the steel box B respectively through the first transverse dowel and the second transverse dowel, and is connected to the column through the upper prestressed longitudinal reinforcement A. When a major earthquake occurs, it can meet the design concept of "strong node, weak member", control the occurrence of plastic hinges at the node position, and yield through the energy consumption of the node to achieve the effect of shock absorption, while facilitating post-earthquake repair and replacement.

[0083] (2) The column-column connection of the present invention is achieved by setting reserved holes at the four corners of the prefabricated assembled hollow concrete column in the middle, and setting spiral stirrups in the reserved holes. The spiral stirrups at the four corners can have a strong restraining effect on the corner concrete, provide an effective restraining effect, and increase the ductility of the concrete, effectively ensuring the seismic performance of the column; by setting longitudinal reinforcement steel bars at the four corners and setting them in the restraining area of the spiral stirrups, and other longitudinal reinforcements are set at the edge of the column, these reinforcements can increase the bearing capacity of the column; by using the middle column stirrups to ensure shear strength, and the middle column stirrup scheme and arrangement are simple, and will not cause manufacturing difficulties; by setting embedded steel pipes in the prefabricated assembled hollow concrete column in the middle, the shear performance of the column-column connection can be effectively enhanced.

[0084] (3) The beams and columns of the present invention are all prefabricated. Under the premise that the connection method can meet the performance of the building such as stability and bearing capacity, wet work on the construction site is reduced, and the installation is convenient and the process is simple, which can save construction time.

[0085] (4) The specific structural design and specific connection method of the present invention are combined together, and the technical effects of various design points are superimposed, so that the constructed box-type connection structure of the connecting column and the composite beam steel box hanging below has stronger stability, bearing capacity, shear resistance and seismic resistance.

[0086] (5) The box-type connection structure and construction method of the connecting column and the composite beam steel box provided by the present invention have the advantages of simple assembly, wide application, good seismic performance, full utilization of reinforcement strength, high constraint effect, and simple construction steps.

[0087] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A box-type connection structure for connecting columns and composite beams with steel boxes hanging down, characterized in that: include: Upper prefabricated assembled hollow concrete columns, middle prefabricated assembled hollow concrete columns, lower prefabricated assembled hollow concrete columns and prefabricated concrete composite beams, among which, The upper prefabricated assembled hollow concrete column is fixedly connected to the upper end of the middle prefabricated assembled hollow concrete column, and the lower prefabricated assembled hollow concrete column is fixedly connected to the lower end of the middle prefabricated assembled hollow concrete column; A first transverse dowel and a second transverse dowel are transversely arranged in the middle of the middle prefabricated assembled hollow concrete column, and the lengths of the first transverse dowel and the second transverse dowel are wider than the width of the middle prefabricated assembled hollow concrete column; The precast concrete composite beam has a groove at the bottom of the beam on one side close to the middle precast assembled hollow concrete column, and a steel box A is embedded in the groove. The steel box A includes a first connecting member and a second connecting member. The first connecting member is a double "mouth" shape connected together in parallel, and its bottom is not closed. The side contacting the middle precast assembled hollow concrete column has two U-shaped openings opening downward, and the opposite side is fixed with the second connecting member, which is a U-shaped groove opening upward; A steel box B is fixed under the steel box A, and the side surface of the steel box B contacts the middle prefabricated assembled hollow concrete column, and the top surface contacts the steel box A; The lower prestressed longitudinal reinforcement of the precast concrete composite beam extends into the U-shaped groove of the second connector, the first transverse dowel is inserted into the U-shaped opening of the first connector, and the second transverse dowel is inserted into the side of the steel box B, thereby achieving a vertical fixed connection between the precast concrete composite beam and the middle precast assembled hollow concrete column; The upper prefabricated assembled hollow concrete column is provided with upper column longitudinal reinforcement, and an upper central hole is prefabricated at the axis; the lower prefabricated assembled hollow concrete column is provided with lower column longitudinal reinforcement, and a lower central hole is prefabricated at the axis; The four corners of the central prefabricated assembled hollow concrete column are prefabricated with reserved holes, and a pre-buried steel pipe is provided at the axis, and both ends of the pre-buried steel pipe extend out of the upper and lower end surfaces of the central prefabricated assembled hollow concrete column; The upper column longitudinal reinforcement and the lower column longitudinal reinforcement are inserted into the reserved holes, and the two ends of the embedded steel pipe are respectively inserted into the upper central hole and the lower central hole to achieve fixed connection of the upper prefabricated assembled hollow concrete column, the middle prefabricated assembled hollow concrete column and the lower prefabricated assembled hollow concrete column; The precast concrete composite beam is provided with an upper prestressed longitudinal reinforcement A, an upper prestressed longitudinal reinforcement B, and a lower prestressed longitudinal reinforcement. The upper prestressed longitudinal reinforcement A and the upper prestressed longitudinal reinforcement B are horizontally arranged at the upper end of the precast concrete composite beam, and the upper prestressed longitudinal reinforcement A and the upper prestressed longitudinal reinforcement B are connected by a steel sleeve; the upper prestressed longitudinal reinforcement A is inserted into the middle precast assembled hollow concrete column; The upper end surface of the middle prefabricated assembled hollow concrete column is provided with reserved openings on both sides, and the upper prestressed longitudinal reinforcement A is inserted into the reserved openings and fixed by pouring concrete.

2. The steel box under-hung box-type connection structure of the connection column and the composite beam according to claim 1 is characterized in that: The upper column longitudinal reinforcement is arranged at the four corners of the upper prefabricated assembled hollow concrete column, and the part located at the lower end of the upper prefabricated assembled hollow concrete column is bent inward and extends longitudinally from the lower bottom surface of the upper prefabricated assembled hollow concrete column; a plurality of groups of upper column stirrups are arranged transversely around the outer periphery of the upper column longitudinal reinforcement in the upper prefabricated assembled hollow concrete column.

3. The steel box under-hung box-type connection structure of the connection column and the composite beam according to claim 1 is characterized in that: The lower column longitudinal reinforcement is arranged at the four corners of the lower prefabricated assembled hollow concrete column, and the part located at the upper end of the lower prefabricated assembled hollow concrete column is bent inward and extends longitudinally from the upper surface of the upper prefabricated assembled hollow concrete column; a plurality of groups of lower column stirrups are arranged transversely on the outer periphery of the lower column longitudinal reinforcement in the lower prefabricated assembled hollow concrete column.

4. The steel box under-hung box-type connection structure of the connection column and the composite beam according to claim 1 is characterized in that: The four corners of the central prefabricated assembled hollow concrete column are further provided with longitudinal reinforcement steel bars, and the longitudinal reinforcement steel bars are arranged on the outside of the reserved holes; the longitudinal reinforcement steel bars are fixed with center column stirrups outside.

5. The steel box under-hung box-type connection structure of the connection column and the composite beam according to claim 1 is characterized in that: The upper prestressed longitudinal reinforcement B and the lower prestressed longitudinal reinforcement are fixed by beam stirrups, and the upper prestressed longitudinal reinforcement A and the lower prestressed longitudinal reinforcement are fixed by open stirrups. The upper end of the open stirrup has an opening, and the two openings are bent downward to fix the upper prestressed longitudinal reinforcement A.

6. The steel box under-hung box-type connection structure of the connection column and the composite beam according to claim 1 is characterized in that: The precast concrete composite beam is also provided with bent ribs, which are arranged at the lower part of the precast concrete composite beam and correspond to the lower position of the upper prestressed longitudinal reinforcement A; a part of the bent rib is arranged on the open stirrup on the steel box A, and the other part penetrates into the bottom of the precast concrete composite beam and is fixed under the open stirrup at the lower prestressed longitudinal reinforcement.

7. A construction method for the steel box-hung box-type connection structure of a connecting column and a composite beam according to any one of claims 1 to 6, comprising the steps of: (1) Prefabricate the required upper prefabricated assembled hollow concrete columns, middle prefabricated assembled hollow concrete columns, lower prefabricated assembled hollow concrete columns and prefabricated concrete composite beams; (2) hoisting the middle prefabricated assembled hollow concrete column above the lower prefabricated assembled hollow concrete column, so that the lower column longitudinal reinforcement extending from the lower prefabricated assembled hollow concrete column passes through the reserved hole of the middle prefabricated assembled hollow concrete column, and the embedded steel pipe of the middle prefabricated assembled hollow concrete column is inserted into the lower hollow hole of the lower prefabricated assembled hollow concrete column; (3) Insert the upper prestressed longitudinal reinforcement A of the precast concrete composite beam through the reserved opening of the middle precast assembled hollow concrete column and into the reserved hole at the far end of the middle precast assembled hollow concrete column so as to be tied with the upper column longitudinal reinforcement inserted into the reserved hole, and then install the steel box B at the second transverse dowel of the middle precast assembled hollow concrete column; (4) Hoist the precast concrete composite beam to the corresponding position, pass the first transverse dowel bar through the U-shaped opening on one side of the steel box A embedded in the precast concrete composite beam, and fix it with bolts; connect the upper prestressed longitudinal bar A and the upper prestressed longitudinal bar B with a steel sleeve; (5) hoisting the upper prefabricated assembled hollow concrete column to the top of the middle prefabricated assembled hollow concrete column, so that the upper column longitudinal reinforcement extending from the upper prefabricated assembled hollow concrete column is inserted into the reserved holes at the four corners of the middle prefabricated assembled hollow concrete column, and the embedded steel pipe of the middle prefabricated assembled hollow concrete column is inserted into the upper hollow hole of the upper prefabricated assembled hollow concrete column; (6) Pour high-strength shrinkage compensation mortar into the reserved holes at the four corners of the middle prefabricated assembled hollow concrete column; (7) Completely hoisting the upper prefabricated assembled hollow concrete column onto the middle prefabricated assembled hollow concrete column; (8) Hoist the composite slab onto the precast concrete composite beam, pour concrete, and complete the construction.

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