Low-rise steel tube concrete modular building node structure and construction method

Abstract

The application provides a low-layer steel pipe concrete modular building node structure and a construction method, and belongs to the technical field of fabricated modular steel structure buildings. The node comprises a prefabricated module, the prefabricated module comprises four steel pipe concrete columns and eight horizontal steel beams; the steel beams are divided into I-shaped side beams and C-shaped channel steel middle beams, and are respectively used on the non-splicing side and the splicing side of the module; the outer side surface of the web of the C-shaped channel steel middle beam is flush with the outer surface of the column, and the webs of the channel steels of adjacent modules are attached and connected through anti-pulling and non-shear bolts; the lower column upper end of the steel pipe concrete column is provided with a reduced-diameter insertion section, and the upper column lower end is provided with a cavity section, a pressure-bearing bottom plate is welded to the inner lower end of the cavity section, the insertion section is inserted into the cavity and tightly abuts against the bottom plate, and the upper column and the lower column are butted. During construction, the module prefabrication is completed in a factory, and the lower module is positioned, the upper column insertion assembly is performed, the beam splicing of adjacent modules is performed and the node post-processing is performed in sequence on the site. The application has a clear force transmission path and improves the seismic redundancy and safety of the structure.

Description

Technical Field

[0001] This invention belongs to the field of prefabricated modular steel tube concrete structure building technology, and in particular relates to a node structure and construction method for low-rise steel tube concrete modular buildings. Background Technology

[0002] In the field of prefabricated building engineering, modular steel-concrete composite structures have become an important development direction for new building industrialization due to their advantages such as high degree of factory prefabrication, short on-site construction cycle, and recyclable components. They are widely used in low-rise and multi-story buildings (5 stories and below) with a high degree of standardization, such as apartments, dormitories, and offices. Existing modular buildings typically prefabricate individual rooms or functional units into complete box modules in the factory, and then complete the main structure assembly on site by hoisting and stacking. The column-column connections and beam-beam connections between modules are the core nodes to ensure the overall structural load-bearing performance.

[0003] In typical node designs for existing low-rise modular steel structure buildings, the corner columns of the modules are mostly made of open-section steel columns such as pure steel pipes or H-beams. After the upper and lower modules are aligned, they are connected by flange bolts. Horizontal steel beams uniformly use H-beams or rectangular steel pipes. The beams and columns are welded together in the factory to form a rigid frame. The parallel beams of adjacent modules are independent of each other, or only weakly connected by floor slab connectors. While this type of design can meet basic assembly requirements, it still has the following technical shortcomings in practical applications: First, steel structure columns are prone to local buckling instability. The corner columns of modular buildings are mostly made of pure steel pipes or open-section steel columns with thin walls. During the transportation and hoisting stage, as well as when subjected to lateral forces such as impacts and earthquakes, thin-walled steel columns are prone to local buckling instability, which leads to a sharp decline in the structural bearing capacity and stability, seriously affecting the safety of the building.

[0004] Secondly, the node connections are complex and the assembly efficiency is low. The beam-column node design of existing modular buildings often includes a variety of irregular components such as flange plates, connecting angle steel, and external stiffeners. The connection methods are complex and require a lot of on-site welding or high-altitude hole-punching and bolting operations, resulting in low assembly efficiency and making it difficult to meet the needs of rapid construction of low-rise and multi-story buildings.

[0005] Third, there is a sudden change in stiffness and poor overall integrity in the joint area. The steel beams of adjacent modules are arranged independently without direct structural connection to each other. They rely solely on inter-story shear connectors to transfer horizontal shear force, resulting in discontinuity in the beam section at the module joint and a significant change in stiffness. The overall horizontal stiffness of the floor slab is insufficient, which easily leads to inter-story slippage at the joint, affecting the structural vibration comfort and overall stress performance.

[0006] Fourth, the column connection has insufficient load-bearing capacity. The bolted connection of the upper and lower column flanges requires high-altitude drilling and bolt insertion in a narrow node area, which is time-consuming. In addition, the bending stiffness of the flange connection is limited, making it difficult to form a continuous force transmission path with the same strength as the column body. The column continuity is insufficient, and its contribution to the overall lateral stiffness of the structure is low.

[0007] Fifth, the stress concentration in the joint area and the lack of differentiated design for component functions. In the existing scheme, the side beams and the intermediate spliced ​​beams adopt the same cross-sectional form, without differentiating the design for the stress characteristics of the modular splicing, resulting in low material utilization efficiency; the welded joint area of ​​beam and column often becomes a stress concentration point, and plastic hinges tend to appear in the joint area prematurely, making it difficult to strictly implement the seismic design principle of "strong joints, weak components", and the seismic redundancy of the structure is insufficient.

[0008] Sixth, the connection between beams of adjacent modules does not achieve a stress distribution system design. In the existing scheme, the steel beams of adjacent modules are either independent of each other or connected by ordinary bolts for omnidirectional shear resistance. Both horizontal and vertical forces are transmitted through column joints, the force transmission path is unclear, and the design redundancy is difficult to define. Summary of the Invention

[0009] In view of this, in order to solve the problems of existing modular buildings, such as easy local buckling and instability of steel columns, complex node connections and low assembly efficiency, sudden change in stiffness and poor integrity in the joint area, insufficient stress performance of column connections, concentrated stress in the node area and lack of differentiated design of component functions, and lack of stress subsystem design for the connection between adjacent module beams, this invention proposes a node structure and construction method for low-rise steel tube concrete modular buildings.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: a low-rise steel-concrete modular building node structure, comprising a prefabricated module, wherein the prefabricated module comprises four vertically arranged steel-concrete columns and eight horizontal steel beams respectively arranged at the top and bottom of the columns; The horizontal steel beams include mutually perpendicular I-shaped side beams and C-shaped channel steel intermediate beams. The I-shaped side beams are set on the periphery of the module and do not splice with adjacent modules. The C-shaped channel steel intermediate beams are set on the side between modules that need to be spliced ​​with the beams of adjacent modules. The outer surface of the web of the C-shaped channel steel intermediate beam is flush with the outer surface of the connected steel pipe concrete column, so that after two adjacent precast modules on the same floor are in place, the outer surfaces of the webs of the corresponding C-shaped channel steel intermediate beams can fit together. The steel-concrete composite column includes a lower column and an upper column. The upper end of the lower column is provided with a reduced-diameter insertion section, and the lower end of the upper column is provided with a cavity section. The lower end of the cavity section is connected to a horizontal bearing base plate. The reduced-diameter insertion section can be inserted into the cavity section and pressed against the base plate to achieve vertical bearing connection between the upper and lower columns.

[0011] Preferably, the intermediate beams of the C-shaped channel steel of two adjacent prefabricated modules on the same floor are bonded together by the web and fastened together by high-strength bolts to form an integral load-bearing beam with an I-shaped cross section.

[0012] Preferably, the high-strength bolt is a pull-out resistant but not shear resistant bolt, comprising a bolt, a washer, and a nut. The bolt passes through a circular hole opened in the web and flange of the intermediate beams of the two C-shaped channel steels. The length of the bolt matches the sum of the thicknesses of the web and flanges of the intermediate beams of the two C-shaped channel steels. The nut is larger than the diameter of the circular hole to ensure that it can be locked at the edge of the hole for limiting during installation. When the intermediate beams of the two C-shaped channel steels are fitted together, the washer fits against the outer side of the web of the intermediate beam of the C-shaped channel steel, and the pull-out resistant but not shear resistant connection is achieved by tightening the nut.

[0013] Preferably, the steel-concrete composite column is composed of an outer steel pipe and an inner concrete filling; the reduced-diameter insertion section is formed by the inward reduction of the cross-section of the steel pipe at the top of the lower column or by welding a small cross-section steel pipe, and the inside of the reduced-diameter insertion section is filled with concrete; the inside of the steel pipe of the cavity section is not filled with concrete, and the inner diameter of the cavity section is larger than the outer diameter of the reduced-diameter insertion section, forming an assembly gap; the base plate is provided with vent holes.

[0014] Preferably, the ends of the I-shaped side beams and C-shaped channel steel intermediate beams near the steel-concrete composite column are provided with thickened areas. The web or flange thickness of the thickened areas is greater than that of the standard beam section, which is used to improve the elastic stiffness of the joint area and force the plastic hinge to form in the beam body outside the thickened areas.

[0015] Preferably, the overlapping section of the reduced-diameter insertion section and the cavity section is provided with a mechanical anti-detachment component to restrict the axial separation of the upper and lower columns; the mechanical anti-detachment component is a transverse through bolt or an anti-pull-out block.

[0016] Preferably, the upper edge of the reduced diameter insertion section is provided with a guide bevel, and the lower opening of the cavity section is provided with a corresponding guide chamfer.

[0017] Preferably, micro-expansion grout is injected into the assembly gap between the reduced-diameter plug section and the cavity section to enhance the integrity and corrosion resistance of the joint.

[0018] A construction method for a low-rise steel-concrete modular building joint structure specifically includes the following steps: S1. Factory prefabricated modules: Process steel pipe columns and steel beam components, complete the welding of I-shaped side beams, C-shaped channel steel intermediate beams and steel pipe concrete columns in the factory to form a module frame; pour concrete into the steel pipe columns, reserve a cavity section at the lower end of the upper column and weld a base plate with vent holes at the lower end of the cavity section, process the upper end of the lower column to form a reduced diameter plug section, and cure the concrete to the design strength. S2. Lower-level module hoisting and positioning: Hoist the first or lower-level prefabricated modules to the designated position on the foundation or lower floor, and temporarily fix them after adjusting the levelness and axis deviation; S3. Upper and lower column insertion assembly: hoist the upper prefabricated module, align the cavity section of the upper column with the reduced diameter insertion section of the lower column of the lower module, and slowly lower it until the end of the reduced diameter insertion section is pressed against the bottom plate to complete the vertical load-bearing connection. S4. Adjacent module beam splicing: After the adjacent prefabricated modules on the same floor are in place, clean the web of the corresponding C-shaped channel steel intermediate beam and align the round hole, insert the threaded rod with washer, the length of the threaded rod is matched with the sum of the thickness of the web and flange on both sides, the size of the nut is larger than the diameter of the round hole, and the hole edge is locked during installation. The initial tightening and final tightening are completed in sequence according to the tightening process, so that the two beams are combined into an integral load-bearing beam, and at the same time, the pull-out-resistant but not shear-resistant connection is achieved. S5. Post-treatment of node area: According to the design requirements, inject micro-expansion high-strength grout or sealant into the column insertion gap, and re-tighten all high-strength bolts. S6. Overall Acceptance: After the module assembly is completed layer by layer, check the node installation gaps, bolt torque, insertion alignment deviation and overall verticality of the module. If it passes the inspection, proceed to the subsequent floor and enclosure construction.

[0019] Preferably, the assembly gap between the outer diameter of the reduced-diameter plug section and the inner diameter of the cavity section is controlled within 3mm, and the net height of the cavity section is within 5mm greater than the length of the reduced-diameter plug section; the webs of the C-shaped channel steel intermediate beam are closely fitted to ensure full contact of the friction surfaces; the concrete of the steel pipe concrete column is transported and hoisted after meeting the design requirements; the grouting pressure is controlled during grouting construction, and the bottom plate is pre-set with grouting holes and vent holes to ensure smooth exhaust.

[0020] Compared with existing technologies, the beneficial effects of the low-rise steel-concrete modular building node structure and construction method described in this invention are: (1) The present invention uses steel-concrete composite columns instead of pure steel columns. The concrete filling effectively suppresses the local buckling deformation of the steel pipe wall, significantly improves the load-bearing capacity and stability of the column under lateral action such as transportation, hoisting, earthquake, and impact, solves the problem of buckling instability of thin-walled steel columns, and improves structural safety.

[0021] (2) The node structure of the present invention is simple. The beams and columns are welded in the factory. The upper and lower columns are connected by a variable cross-section plug-in type. The adjacent module channel steel beams are spliced ​​together by high-strength bolts. There is no need for a large amount of welding or high-altitude hole-piercing bolting on site. The connection components are few and the assembly efficiency is high, which meets the needs of rapid construction of low-rise and multi-story buildings.

[0022] (3) The present invention uses a structural design in which the outer side of the web of the C-shaped channel steel intermediate beam is flush with the outer surface of the column, so that the webs of the adjacent module channel steel are attached and connected by high-strength bolts to form an I-shaped integral load-bearing beam, thereby realizing the continuous transition of the beam section at the joint, eliminating abrupt changes in stiffness, and significantly improving the overall horizontal stiffness and integrity of the floor slab.

[0023] (4) The upper and lower columns of the present invention adopt a connection method of inserting the reduced diameter plug section into the cavity section and pressing it against the bottom plate. The vertical force is directly transmitted through the end face bearing pressure. The sleeve area resists bending in a coordinated manner, forming a continuous force transmission path with the same strength as the column body. The column continuity and lateral stiffness are better than the traditional flange connection.

[0024] (5) The present invention uses differentiated configuration of I-shaped side beams and C-shaped channel steel middle beams to match the cross-sectional form according to the stress requirements of the module, resulting in high material utilization efficiency; the thickened area design at the beam end moves the plastic hinge outside the node area, strictly follows the seismic design principle of "strong node, weak component", and improves the seismic redundancy and safety of the structure.

[0025] (6) In this invention, the adjacent module channel steel beams are connected by pull-out resistant but not shear resistant bolts with round holes. The nut size is larger than the diameter of the round hole to achieve installation and positioning limit. The length of the bolt is matched with the sum of the thickness of the web and flange of the two side beams. Pull-out resistance is achieved by the fit of the washer with the web of the channel steel. The gap between the round hole and the bolt is reserved to achieve horizontal non-shear resistance.

[0026] (7) The force transmission path of this invention is clear: the downward pressure generated by the structural self-weight, service load, and vertical seismic action is borne by the steel-concrete composite columns; the uplift force generated by the vertical seismic action and the upward pull force caused by the overall overturning of the wind load are borne by the structural self-weight and the "pull-out but not shear" bolts; the lateral inter-story shear force is mainly borne by the splicing area of ​​the reduced diameter plug-in section of the upper and lower columns, and the plug-in section also cooperates in resisting bending; the horizontal steel beam is the coordinating component between the vertical components, and the adjacent module channel steel beams are bolted together to form an integral beam, which transmits the horizontal force of the floor slab and coordinates the deformation of each vertical component; the clear force transmission mode of beam-slab-column is still maintained under normal service load. Thus, the force subsystem design is realized and the force transmission path is clear. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the modular building node structure of low-rise steel-concrete composite building provided by the present invention. Figure 2 This is the present invention. Figure 1 Axonometric view of the nodal region in the diagram; Figure 3 This is the present invention. Figure 2A front view of the node region; Figure 4 This is the present invention. Figure 3 Section 1-1 of the node region; Figure 5 These are isometric views and partial sectional views of the upper and lower module column plug-in nodes of the present invention; Figure 6 This is a schematic diagram of the connection structure of the pull-out resistant but not shear resistant bolt of the present invention.

[0028] In the diagram: 100 - Precast module; 10 - Steel-concrete composite column; 11 - Lower column; 111 - Reduced diameter plug-in section; 12 - Upper column; 121 - Cavity section; 122 - Base plate; 122a - Vent hole; 20 - Horizontal steel beam; 21 - I-shaped side beam; 22 - C-shaped channel steel intermediate beam; 22a - Web plate; 22b - Flange; 30 - High-strength bolt; 301 - Screw; 302 - Large diameter washer; 303 - Nut; 40 - Thickened area; 50 - Guide slope. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the drawings, and not all of them. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the invention.

[0030] For ease of description, taking the normal use state of a single prefabricated module as a reference, the floor plan direction of the module is defined as the horizontal plane, and the vertical direction is defined as the vertical direction. For two stacked modules, the lower one is called the lower module, and the higher one is called the upper module. The top of the column of the lower module is called the lower column, and the bottom of the column of the upper module is called the upper column. This invention is applicable to multi-story modular steel-concrete composite structure buildings. The specifications of high-strength bolts can be selected from M20 to M24 according to the force, and the applicable range of column cross-section side length or diameter is 100mm to 400mm.

[0031] See Figure 1-6This embodiment describes a low-rise steel-concrete composite modular building node structure, including prefabricated modules 100. Each prefabricated module 100 includes four vertically arranged steel-concrete composite columns 10 and eight horizontal steel beams 20 respectively located at the top and bottom of the columns. The horizontal steel beams 20 are divided into I-shaped side beams 21 and C-shaped channel steel intermediate beams 22. The I-shaped side beams 21 are located on the periphery of the module and do not connect with adjacent modules. The C-shaped channel steel intermediate beams 22 are located on the sides between modules that need to connect with the beams of adjacent modules. The outer surface of the web 22a of the C-shaped channel steel intermediate beam 22 is flush with the outer surface of the connected steel-concrete composite column 10, allowing two adjacent prefabricated modules 100 on the same floor to be aligned. After the C-shaped channel steel intermediate beams 22 are in place, the outer surfaces of the web plates 22a of the corresponding C-shaped channel steel intermediate beams 22 can fit together; the steel-concrete composite column 10 is divided into a lower column 11 and an upper column 12. The upper end of the lower column 11 is provided with a reduced diameter insertion section 111, and the lower end of the upper column 12 is provided with a cavity section 121. The lower end of the cavity section 121 is welded with a horizontal bearing base plate 122. The reduced diameter insertion section 111 can be inserted into the cavity section 121 and pressed against the base plate 122 to realize the vertical bearing connection of the upper and lower columns; the C-shaped channel steel intermediate beams 22 of two adjacent prefabricated modules 100 on the same floor fit together through the web plates 22a and are fastened together by high-strength bolts 30 to form an integral load-bearing beam with an I-shaped cross section.

[0032] The steel-concrete composite column 10 is composed of an outer steel pipe and an inner concrete filling; the reduced-diameter insertion section 111 is formed by the inward reduction of the cross section of the steel pipe at the top of the lower column 11 or by welding a small cross section steel pipe, and the inside of the reduced-diameter insertion section 111 is filled with concrete; the inside of the steel pipe of the cavity section 121 is not filled with concrete, and the inner diameter of the cavity section 121 is larger than the outer diameter of the reduced-diameter insertion section 111, forming an assembly gap; the base plate 122 is provided with an exhaust hole 122a.

[0033] The high-strength bolt 30 is a pull-out resistant but not shear resistant bolt, including a screw 301, a washer 302, and a nut 303. The screw 301 passes through a circular hole in the web 22a and flange 22b of the two C-shaped channel steel intermediate beams 22. The length of the screw 301 matches the sum of the thicknesses of the web and flanges of the two C-shaped channel steel intermediate beams 22. The nut 303 is larger than the diameter of the circular hole to ensure that it can be locked at the edge of the hole for limiting during installation. When the two C-shaped channel steel intermediate beams 22 are fitted together, the washer 302 fits against the outer surface of the web 22a of the C-shaped channel steel intermediate beam 22, and the pull-out resistant but not shear resistant connection is achieved by tightening the nut 303, allowing the horizontal force dependent on the column and the vertical force dependent on the beam to be designed separately. The ends of the I-shaped side beam 21 and the C-shaped channel steel intermediate beam 22 near the steel tube concrete column 10 are both provided with thickened areas 40. The thickness of the web or flange of the thickened area 40 is greater than that of the standard section of the beam body, which is used to improve the elastic stiffness of the joint area and force the plastic hinge to form in the beam body outside the thickened area 40.

[0034] The overlapping section of the reduced diameter plug section 111 and the cavity section 121 is provided with a mechanical anti-detachment component that restricts the axial separation of the upper and lower columns; the mechanical anti-detachment component is a transverse through bolt or an anti-pull-out block.

[0035] The upper edge of the reduced diameter plug section 111 is provided with a guide slope 50, and the lower opening of the cavity section 121 is provided with a guide chamfer.

[0036] Micro-expansion grout can be injected into the assembly gap between the reduced diameter plug section 111 and the cavity section 121 to enhance the integrity and corrosion resistance of the joint.

[0037] A construction method for a low-rise steel-concrete modular building joint structure includes the following steps: S1. Factory prefabrication module: Process steel pipe columns and steel beam components. Weld the I-shaped side beam 21, C-shaped channel steel intermediate beam 22 and steel pipe concrete column 10 in the factory to form a module frame. Pour concrete into the steel pipe column. Reserve a cavity section 121 at the lower end of the upper column 12 and weld a base plate 122 with vent holes 122a inside the lower end of the cavity section 121. Process the upper end of the lower column 11 to form a reduced diameter plug section 111. Cure the concrete to the design strength. S2. Lower-level module hoisting and positioning: Hoist the first or lower-level prefabricated module 100 to the designated position on the foundation or lower floor, and temporarily fix it after adjusting the levelness and axis deviation; S3. Upper and lower column insertion assembly: hoist the upper prefabricated module 100, align the cavity section 121 of the upper column 12 with the reduced diameter insertion section 111 of the lower column 11 of the lower module, and slowly lower it until the end of the reduced diameter insertion section 111 is pressed against the bottom plate 122 to complete the vertical load-bearing connection. S4. Adjacent module beam splicing: After the adjacent prefabricated modules 100 on the same floor are in place, clean the mating surface of the web 22a of the corresponding C-shaped channel steel intermediate beam 22 and align the round hole, insert the screw 301 with washer 302, the length of the screw 301 matches the sum of the thickness of the web and flange on both sides, the size of the nut 303 is larger than the diameter of the round hole, and the hole edge is locked during installation. The initial tightening and final tightening are completed in sequence according to the tightening process, so that the beams on both sides are combined into an integral load-bearing beam, and at the same time, the pull-out-resistant but not shear-resistant connection is achieved. S5. Post-treatment of node area: According to the design requirements, inject micro-expansion high-strength grout or sealant into the column insertion gap, and re-tighten all high-strength bolts 30. S6. Overall Acceptance: After the module assembly is completed layer by layer, check the node installation gaps, bolt torque, insertion alignment deviation and overall verticality of the module. If it passes the inspection, proceed to the subsequent floor and enclosure construction.

[0038] The assembly gap between the outer diameter of the reduced-diameter plug section 111 and the inner diameter of the cavity section 121 is controlled within 3mm, and the net height of the cavity section 121 is within 5mm greater than the length of the reduced-diameter plug section 111; the web plates 22a of the C-shaped channel steel intermediate beam 22 fit together to ensure full contact of the friction surfaces; the concrete of the steel pipe concrete column 10 must meet the design requirements before transportation and hoisting operations can be carried out; the grouting pressure is controlled during grouting construction, and the bottom plate 122 is pre-set with grouting holes and vent holes to ensure smooth exhaust.

[0039] In summary, this invention provides a structural design and construction method for a low-rise steel-concrete composite modular building joint. It replaces pure steel columns with steel-concrete composite columns, utilizing the supporting effect of the inner concrete filling on the steel pipe wall to effectively suppress local buckling deformation of thin-walled steel columns under lateral forces such as transportation, hoisting, earthquakes, and impacts. This significantly improves the column's load-bearing capacity and stability, ensuring building safety. The joint structure is simple; beams and columns are welded in the factory, and the upper and lower columns are connected by a variable cross-section plug-in joint. Adjacent modular channel steel beams are joined together with high-strength bolts, eliminating the need for extensive on-site welding or high-altitude bolting. This reduces the number of connecting components and increases assembly efficiency, meeting the rapid construction needs of low-rise and multi-story buildings. The design, with the outer side of the web of the C-shaped channel steel intermediate beam flush with the outer surface of the column, allows adjacent modular channel steel webs to be joined and connected with high-strength bolts, forming an I-shaped integral load-bearing beam. This achieves a continuous transition of the beam section at the joint, eliminating abrupt changes in stiffness and significantly improving the overall horizontal stiffness and integrity of the floor slab. The upper and lower columns are connected by a reduced-diameter plug-in section inserted into the cavity section and pressed tightly against the base plate. Vertical forces are directly transmitted through end-face bearing pressure, and the sleeve area cooperates in resisting bending, forming a continuous force transmission path with the same strength as the column body. The column continuity and lateral stiffness are superior to traditional flange connections. Differentiated configuration of I-shaped edge beams and C-shaped channel steel intermediate beams, matching the cross-sectional form according to the module's stress requirements, results in high material utilization efficiency. The thickened area design at the beam ends moves the plastic hinge outside the node area, strictly adhering to the seismic design principle of "strong nodes, weak components". Adjacent module channel steel beams are connected by pull-out resistant but not shear resistant bolts and large-diameter circular holes, realizing a force distribution system design where horizontal forces depend on the column and vertical forces depend on the beam. The force transmission path is clear, improving the structure's seismic redundancy and safety.

[0040] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A modular building joint structure for low-rise steel-concrete composite structures, characterized in that: It includes a prefabricated module (100), which includes four vertically arranged steel-concrete composite columns (10) and eight horizontal steel beams (20) respectively arranged at the top and bottom of the column. The horizontal steel beam (20) includes mutually perpendicular I-shaped side beams (21) and C-shaped channel steel intermediate beams (22). The I-shaped side beams (21) are set on the side of the module that are not spliced ​​with adjacent modules. The C-shaped channel steel intermediate beams (22) are set on the side of the module that need to be spliced ​​with the beams of adjacent modules. The outer side of the web plate (22a) of the C-shaped channel steel intermediate beam (22) is flush with the outer surface of the connected steel pipe concrete column (10), so that after two adjacent prefabricated modules (100) on the same floor are in place, the outer sides of the web plate (22a) of the corresponding C-shaped channel steel intermediate beams (22) can fit together. The steel-concrete composite column (10) includes a lower column (11) and an upper column (12). The upper end of the lower column (11) is provided with a reduced diameter insertion section (111), and the lower end of the upper column (12) is provided with a cavity section (121). The lower end of the cavity section (121) is connected to a base plate (122). The reduced diameter insertion section (111) can be inserted into the cavity section (121) and pressed against the base plate (122) to realize the vertical load-bearing connection between the upper and lower columns.

2. The low-rise steel-concrete modular building node structure according to claim 1, characterized in that: The C-shaped channel steel intermediate beams (22) of two adjacent prefabricated modules (100) on the same floor are attached to each other through the web (22a) and fastened together by high-strength bolts (30) to form an integral load-bearing beam with an I-shaped cross section.

3. The low-rise steel-concrete modular building node structure according to claim 2, characterized in that: The high-strength bolt (30) is a pull-out resistant but not shear resistant bolt, including a screw (301), a washer (302) and a nut (303). The screw (301) passes through the circular holes opened on the web (22a) and flange (22b) of the two C-shaped channel steel intermediate beams (22). The length of the screw (301) matches the sum of the thickness of the web and flange of the two C-shaped channel steel intermediate beams (22). The size of the nut (303) is larger than the diameter of the circular hole to ensure that it can be locked at the edge of the hole to achieve a limit during installation. When the two C-shaped channel steel intermediate beams (22) are fitted together, the washer (302) is fitted with the outer side of the web (22a) of the C-shaped channel steel intermediate beam (22), and the pull-out resistant but not shear resistant connection is achieved by tightening the nut (303).

4. The low-rise steel-concrete modular building node structure according to claim 1, characterized in that: The steel-concrete composite column (10) is composed of an outer steel pipe and an inner concrete filling; the reduced diameter plug section (111) is formed by the inward reduction of the cross section of the steel pipe at the top of the lower column (11) or by welding a small cross section steel pipe, and the inside of the reduced diameter plug section (111) is filled with concrete; the inside of the steel pipe of the cavity section (121) is not filled with concrete, and the inner diameter of the cavity section (121) is larger than the outer diameter of the reduced diameter plug section (111), forming an assembly gap; the bottom plate (122) is provided with an exhaust hole (122a).

5. The low-rise steel-concrete modular building node structure according to claim 1, characterized in that: The ends of the I-shaped side beam (21) and the C-shaped channel steel intermediate beam (22) near the steel pipe concrete column (10) are provided with thickened areas (40). The thickness of the web or flange of the thickened area (40) is greater than that of the standard section of the beam body, which is used to improve the elastic stiffness of the joint area and force the plastic hinge to form in the beam body outside the thickened area (40).

6. The low-rise steel-concrete modular building node structure according to claim 1, characterized in that: The overlapping section of the reduced diameter plug section (111) and the cavity section (121) is provided with a mechanical anti-detachment component to restrict the axial separation of the upper and lower columns; the mechanical anti-detachment component is a transverse through bolt or an anti-pull-out block.

7. The low-rise steel-concrete modular building node structure according to claim 1, characterized in that: The upper edge of the reduced diameter plug section (111) is provided with a guide slope (50), and the lower opening of the cavity section (121) is provided with a guide chamfer.

8. The low-rise steel-concrete modular building node structure according to claim 1, characterized in that: Micro-expansion grout is injected into the assembly gap between the reduced diameter plug section (111) and the cavity section (121) to enhance the integrity and corrosion resistance of the joint.

9. A construction method for a low-rise steel-concrete modular building joint structure as described in any one of claims 1-8, characterized in that: Specifically, the steps include the following: S1, Factory prefabrication module: Process steel pipe columns and steel beam components, complete the welding of I-shaped side beams (21), C-shaped channel steel intermediate beams (22) and steel pipe concrete columns (10) in the factory to form a module frame; pour concrete into the steel pipe columns, reserve a cavity section (121) at the lower end of the upper column (12) and weld a bottom plate (122) with vent holes (122a) at the lower end inside the cavity section (121), process the upper end of the lower column (11) to form a reduced diameter plug section (111), and cure the concrete to the design strength; S2. Lower-level module hoisting and positioning: Hoist the first or lower-level prefabricated module (100) to the designated position on the foundation or lower floor, adjust the levelness and axis deviation, and then temporarily fix it. S3. Upper and lower column plug-in assembly: hoist the upper prefabricated module (100) so that the cavity section (121) of the upper column (12) is aligned with the reduced diameter plug-in section (111) of the lower column (11) of the lower module. Slowly lower it until the end of the reduced diameter plug-in section (111) is pressed against the bottom plate (122) to complete the vertical load-bearing connection. S4. Adjacent module beam splicing: After the adjacent prefabricated modules (100) on the same floor are in place, clean the mating surface of the web (22a) of the corresponding C-shaped channel steel intermediate beam (22) and align the round hole, insert the screw (301) with washer (302), the length of the screw (301) matches the sum of the thickness of the web and flange on both sides, the size of the nut (303) is larger than the diameter of the round hole, and the hole edge is locked during installation. The initial tightening and final tightening are completed in sequence according to the tightening process, so that the beams on both sides are combined into an integral load-bearing beam, and at the same time, the pull-out-resistant but not shear-resistant connection is achieved. S5. Post-treatment of node area: According to the design requirements, inject micro-expansion high-strength grout or sealant into the column insertion gap, and re-tighten all high-strength bolts (30). S6. Overall Acceptance: After the module assembly is completed layer by layer, check the node installation gaps, bolt torque, insertion alignment deviation and overall verticality of the module. If it passes the inspection, proceed to the subsequent floor and enclosure construction.

10. The construction method for the low-rise steel-concrete modular building node structure according to claim 9, characterized in that: The assembly gap between the outer diameter of the reduced diameter plug section (111) and the inner diameter of the cavity section (121) is controlled within 3mm, and the net height of the cavity section (121) is within 5mm larger than the length of the reduced diameter plug section (111); the web plates (22a) of the intermediate beam of the C-shaped channel steel (22) fit together to ensure full contact of the friction surfaces; the concrete of the steel pipe concrete column (10) is transported and hoisted after meeting the design requirements; the grouting pressure is controlled during grouting construction, and the grouting holes and vent holes are pre-set in the bottom plate to ensure smooth exhaust.

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