Modular U-shaped connecting joint of composite floor slab and construction method

Abstract

The invention discloses a modular U-shaped connecting joint of a composite floor slab and a construction method, and relates to the technical field of fabricated building component connection. The core is that an integrated connecting structure is formed by embedding and meshing of an integrated frame and a U-shaped connecting assembly, and the integrated connecting structure comprises the integrated frame, a foam concrete filling layer, a lightweight aggregate concrete pouring layer, distributed steel bars, the U-shaped connecting assembly and an embedded pipeline. The overall frame is formed by welding longitudinal and transverse profile steel keels, the U-shaped connecting assemblies construct a vertical fastening and horizontal limiting two-way constraint system through high-strength bolts, and the structure connection function, the heat preservation sealing function and the pipeline avoiding function are integrated. The problems that a traditional connecting joint is poor in integrity, heat preservation fractures, tedious in construction and the like are solved, load bearing-enclosure-heat preservation integration is achieved, the assembly efficiency is greatly improved through factory modular prefabrication and an on-site dry type construction mode, and the prefabricated joint is suitable for various kinds of assembly type building engineering and meets the requirements for green energy saving and building industrialization development.

Description

Technical Field

[0001] This invention relates to the field of prefabricated building component connection technology, specifically to a modular U-shaped connection node for composite floor slabs and its construction method. Background Technology

[0002] With the deep integration of industrialized building and green energy-saving concepts, prefabricated steel structure buildings have become the core direction of industry transformation. Light steel foam concrete composite floor slabs, with their integrated "load-bearing, insulation, and enclosure" characteristics, have become the core horizontal component of this system. However, in actual projects, the performance defects of the floor slab joint connection nodes have become a key bottleneck restricting its large-scale application.

[0003] Currently, the five main types of floor slabs used in engineering (cast-in-place reinforced concrete floor slabs, steel truss floor slabs, precast concrete composite floor slabs, profiled steel sheet-concrete composite floor slabs, and lightweight sheet floor slabs) each have their own technical limitations: cast-in-place reinforced concrete floor slabs have strong integrity but involve a lot of wet work, have long construction periods, and are heavy; steel truss floor slabs are highly efficient to construct but have high costs and limited seismic performance; precast concrete composite floor slabs have high assembly rates but are prone to cracking and leakage at the joints, and transportation costs increase significantly due to the reinforcing bars; profiled steel sheet-concrete composite floor slabs have excellent rigidity but have high costs for corrosion and fire protection, and the steel ribs are prone to forming continuous thermal bridges; lightweight sheet floor slabs are lightweight but have low load-bearing capacity and require strict waterproofing at joints. Traditional connection methods for these floor slabs are generally unsuitable for the composite structural characteristics of lightweight steel foam concrete composite floor slabs, resulting in problems such as poor overall connection integrity, disruption of insulation continuity, high construction precision requirements, disconnect between waterproofing and connection, and easy interference with pipelines during construction.

[0004] The lightweight steel foam concrete composite floor system developed in the industry uses C-shaped steel keel as the core load-bearing component. The longitudinal and transverse keels are welded into an integral frame, and foam concrete is poured inside. Lightweight aggregate concrete is poured on the top and bottom layers, and water, electricity and heating pipelines are pre-embedded in the foam concrete layer. It has the advantages of high assembly rate, excellent mechanical properties, low self-weight, good heat preservation and convenient pipeline layout. However, the connection of the slab joints of this system has become a technical pain point. Traditional connection methods cannot take into account structural reliability, heat preservation continuity and construction convenience.

[0005] Traditional slab joint connectors are mostly general-purpose components, requiring on-site cutting and adjustment according to the slab dimensions, resulting in low fitting accuracy and cumbersome construction. Traditional slab joint bolt connections can only achieve vertical tightening, lacking horizontal restraint, making them prone to lateral displacement of the slab due to building vibration or load. Furthermore, traditional connection nodes struggle to integrate structural connection, thermal insulation, and pipeline avoidance functions, hindering the full realization of the composite floor slab's overall performance. Therefore, this invention proposes a modular U-shaped connection node for composite floor slabs and a construction method to solve the aforementioned technical problems. Summary of the Invention

[0006] This invention aims to provide a modular U-shaped connection node and construction method for composite floor slabs, solving the technical problems of poor overall integrity, single function, lack of constraint system, imbalance between insulation and load-bearing, easy leakage at slab joints, and easy damage to pipelines in existing light steel foam concrete composite floor slab connection nodes, realizing the integrated function of "load-bearing-enclosure-insulation", and improving construction efficiency and assembly quality.

[0007] To achieve the above objectives, the technical solution of the present invention is implemented as follows: A modular U-shaped connection node for composite floor slabs includes several integral composite floor slabs interconnected by U-shaped connection components. Each integral composite floor slab includes an integral frame, a filling layer, a pouring layer, distributed reinforcing bars, and embedded pipelines. The components work together to achieve a firm connection between the floor slab and the steel beams, as well as integrated functions of seismic resistance, load-bearing, and thermal insulation. The overall frame is the core load-bearing carrier. It is formed by welding longitudinal and transverse steel keels to form a spatial grid structure. The steel keels are made of high-strength steel. The longitudinal and transverse keels are derusted before welding. The steel beams of the steel keels at both ends of the overall frame are reserved with fitting grooves that are compatible with U-shaped connectors. The width of the grooves matches the flange width of the U-shaped connectors. The filling layer is foamed concrete, which is poured into the internal cavity of the overall frame and adheres to the inner wall of the steel keel. Reinforcing materials can be selectively added to the foamed concrete, and pre-embedded channels for pipelines are reserved inside. The pouring layer is lightweight aggregate concrete, including top lightweight aggregate concrete and bottom lightweight aggregate concrete covering the overall frame. The pouring height is determined according to the load-bearing capacity of the steel beam. The distributed reinforcement includes longitudinal distributed reinforcement and transverse distributed reinforcement. The longitudinal distributed reinforcement is fixedly connected to the steel keel of the overall frame, and the transverse distributed reinforcement is inserted inside the longitudinal distributed reinforcement. Both are laid in the lightweight aggregate concrete. The U-shaped connection assembly includes a U-shaped connector, positioning fasteners, and thermal insulation pads. The U-shaped connector has pre-drilled bolt holes on both wings to accommodate high-strength bolts. The heads of the high-strength bolts and the slots of the U-shaped connector form an interlocking structure. The positioning fasteners are used for fixing and locking during the installation stage. The thermal insulation pads are located inside the U-shaped connector. The pre-embedded pipelines are made of corrosion-resistant materials and are embedded in a special channel of foamed concrete, without interfering with the overall frame or U-shaped connectors.

[0008] Furthermore, the steel keel is one of C-shaped steel, H-shaped steel or square steel pipe, and the cross-sectional height of the steel keel is 120-160mm, the flange width is 50-70mm, and the thickness is 1.5-2.5mm.

[0009] Furthermore, the reinforcing material is one or more of polypropylene fiber, glass fiber, or steel fiber, and the amount of reinforcing material in the foamed concrete is 3%-10%.

[0010] Furthermore, the longitudinally distributed reinforcing bars have a diameter of 8-12mm × 400-600mm, and the transversely distributed reinforcing bars have a diameter of 12-20mm and a spacing of 4000-5500mm.

[0011] Furthermore, the high-strength bolts are galvanized bolts of grade 6.8, 8.8, or 10.9, with a bolt shank diameter of 10-18mm, and the bolt holes reserved on both wings of the U-shaped connector have a diameter of 10-18mm.

[0012] Furthermore, the positioning fastener includes an auxiliary positioning bolt and a lock nut. The auxiliary positioning bolt is used for temporary fixation during the hoisting stage, and the lock nut is used for locking and fixing.

[0013] Furthermore, a grouting groove is reserved at the top of the U-shaped connector. After the node is tightened, micro-expansion waterproof mortar or sealant is injected to form a top seal.

[0014] Furthermore, reinforcing ribs are added to the overall frame at the four corners of the floor slab. The thickness of the ribs is the same as that of the web of the steel keel, and the height is the same as that of the keel cross-section. They are fixed by welding or bolts.

[0015] Furthermore, the corrosion-resistant material is one of PVC, PE, PPR or stainless steel.

[0016] To achieve the above objectives, the present invention also provides a construction method using the above-described connection nodes, comprising the following steps: (1) Factory prefabrication stage: Steel keel is processed according to the design dimensions, and after rust removal, it is welded to form an overall frame. U-shaped connector fitting groove and bolt holes are reserved; the top and bottom distributed steel bars are fixedly connected to the overall frame; foam concrete is poured into the cavity inside the overall frame, and water, electricity and heating pipelines are pre-embedded at the same time; lightweight aggregate concrete is poured on the top and bottom of the overall frame to complete the prefabrication of single-piece integral composite floor slabs; at the same time, the U-shaped connectors are formed, the thermal insulation pads are installed and the anchors are fixed in the factory to form modular connection components. (2) On-site installation stage: transport the prefabricated integral composite floor slab to the construction site, hoist it into place, and then connect the open side of the U-shaped connector with the steel keel groove at the end of the floor slab; fine-tune the accuracy of the slab joint by using positioning fasteners and lock it in place; inject sealing material into the grouting groove at the top of the U-shaped connector to complete the slab joint sealing; connect the water, electricity and heating pipelines and debug them; clean the construction site and complete the overall installation.

[0017] Beneficial effects: (1) Strong integrity and wide range of applicability: Through the composite connection form of "steel keel inlay + U-bolt bidirectional fastening", a stable mechanical transmission system is constructed. The U-shaped connector and the steel keel surface are in contact and inlay to realize the initial transmission of horizontal shear force. The high-strength bolts will evenly transmit the vertical load, and the distributed steel bars will disperse the force to the concrete layer, effectively solving the problems of poor integrity and horizontal displacement of traditional connections. At the same time, the key parameters such as steel keel type, size, bolt grade, and type of reinforcing material are all set within a reasonable range to adapt to different load levels and spans of building scenarios, expanding the application coverage of the technical solution.

[0018] (2) Functional integration: Integrating the three core functions of structural connection, thermal insulation and sealing, and pipeline avoidance, foam concrete and thermal insulation pad work together to achieve built-in insulation, block the thermal bridge effect, and meet energy-saving requirements; micro-expansion waterproof mortar or sealant seals the board joints to solve the leakage problem; the pre-embedded pipeline design avoids on-site trenching and damage to the structure, realizing the integration of "load-bearing-enclosure-thermal insulation" and overcoming the defects of traditional node functions not being coordinated.

[0019] (3) Efficient and convenient construction: The factory modular prefabrication mode is adopted, the components are produced in a standardized manner, the size is accurate and the quality is controllable. On-site, only dry construction processes such as fitting, bolt fixing and sealing are required. No secondary processing is required. It saves more than half of the working time compared with the traditional reinforced concrete floor slab construction method, greatly reduces the amount of wet work, reduces the dependence on hoisting accuracy and manual adjustment, speeds up the project progress and reduces construction costs.

[0020] (4) Energy-saving, environmentally friendly and durable: The use of lightweight materials such as foamed concrete and lightweight aggregate concrete reduces the load on the upper part of the building and the pressure on the foundation, saving project costs and transportation energy consumption; all materials used are green and environmentally friendly products, no additional insulation layer is required, saving resources such as wood, and meeting the requirements of green building energy conservation and environmental protection; high-strength galvanized bolts, corrosion-resistant pipelines and perfect waterproof sealing measures effectively improve the anti-corrosion and waterproof performance of nodes, extend service life and reduce maintenance costs.

[0021] (5) High policy fit: It is applicable to prefabricated construction projects such as high-rise civil buildings, large public buildings and large-span industrial plants of various heights. It fully complies with the national policy requirements of vigorously developing the prefabricated industry and promoting the industrialization and green energy-saving transformation of the building industry, and has broad prospects for promotion and application. Attached Figure Description

[0022] 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 1This is a schematic diagram of an integral composite floor slab with modular U-shaped connection nodes as described in an embodiment of the present invention. Figure 2 This is a schematic diagram of the modular U-shaped connection node of the composite floor slab in an embodiment of the present invention. Figure 3 This is a schematic diagram of the overall frame of the modular U-shaped connection node of the composite floor slab according to an embodiment of the present invention; Figure 4 This is a three-dimensional structural diagram of the modular U-shaped connection node of the composite floor slab according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the distributed reinforcing bars in the modular U-shaped connection node of the composite floor slab according to an embodiment of the present invention; Figure 6 This is a basic structural diagram of the U-bolts for the modular U-shaped connection node of the composite floor slab described in this embodiment of the invention; Figure 7 This is a schematic diagram of the overall floor slab top plane connection of the modular U-shaped connection node of the composite floor slab according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the overall floor slab bottom plane connection of the modular U-shaped connection node of the composite floor slab according to an embodiment of the present invention. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0024] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] Example 1 See Figure 1-8 A modular U-shaped connection node for composite floor slabs includes several integral composite floor slabs 1 interconnected by U-shaped connection components. Each integral composite floor slab 1 includes an integral frame 5, a filling layer, a pouring layer, distributed steel bars, and embedded pipelines 3. The components work together to achieve a firm connection between the floor slab and the steel beams and to integrate the functions of seismic resistance, load-bearing, and thermal insulation. The overall frame 5 is the core load-bearing carrier. It is formed by welding longitudinal and transverse steel keels to form a spatial grid structure. The steel keels are made of high-strength steel. The longitudinal and transverse keels are derusted before welding. The steel beams of the steel keels at both ends of the overall frame 5 are reserved with fitting grooves that are compatible with the U-shaped connectors 7. The width of the grooves matches the flange width of the U-shaped connectors 7. The filling layer is foamed concrete 6, which is poured into the internal cavity of the overall frame 5 and adheres to the inner wall of the steel keel. Reinforcing materials can be selectively added to the foamed concrete 6, and pre-embedded channels for pipelines are reserved inside. The pouring layer is lightweight aggregate concrete, including top lightweight aggregate concrete 2 and bottom lightweight aggregate concrete 2' covering the overall frame 5. The pouring height is determined according to the load-bearing capacity of the steel beam. The distributed reinforcement includes longitudinal distributed reinforcement 4 and transverse distributed reinforcement 4'. The longitudinal distributed reinforcement 4 is fixedly connected to the steel keel of the overall frame 5, and the transverse distributed reinforcement 4' is inserted inside the longitudinal distributed reinforcement 4. Both are laid in the lightweight aggregate concrete. The U-shaped connection assembly includes a U-shaped connector 7, positioning fasteners, and thermal insulation pads. The U-shaped connector 7 has pre-drilled bolt holes on both wings to accommodate high-strength bolts. The heads of the high-strength bolts and the slots of the U-shaped connector 7 form an interlocking structure. The positioning fasteners are used for fixing and locking during the installation stage. The thermal insulation pads are located inside the U-shaped connector 7. The pre-embedded pipeline 3 is made of corrosion-resistant material and is pre-embedded in a special channel of foamed concrete 6, without interfering with the overall frame 5 or the U-shaped connector 7.

[0026] It should be noted that this embodiment innovatively designs a U-shaped bolt head and a two-way slot interlocking structure through a U-shaped connecting component. While the U-shaped main bolt completes vertical fastening, its head can form a horizontal limit with the slot of the U-shaped connector. Combined with the temporary fixing of the auxiliary positioning bolt and the locking of the anti-loosening nut, a two-way constraint fastening system of "vertical fastening + horizontal limit" is constructed to ensure the stability of the connection node in long-term use and avoid displacement deviation between floor slabs.

[0027] This embodiment innovatively constructs a mechanical transmission system of "C-shaped steel keel fitting - U-shaped bolt fastening" for the U-shaped connection node: First, the main body of the U-shaped connector is precisely fitted with the steel beam of the C-shaped steel keel at the end of the floor slab, forming a preliminary mechanical constraint of surface contact, realizing the preliminary transmission of horizontal shear force; Second, the U-shaped main bolt penetrates the connector and the keel, forming a vertical fastening constraint through the bolt pre-tightening force, uniformly transmitting the vertical load of the adjacent floor slab; dispersing the force of the connector to the concrete layer.

[0028] The lightweight steel-foamed concrete composite floor slab adapted to this connection node is composed of C-shaped steel, foamed concrete, lightweight aggregate concrete, and reinforcing bars. Foamed concrete and lightweight aggregate concrete are porous and lightweight materials with low thermal conductivity, enabling built-in insulation of the floor slab without the need for additional insulation layers. At the same time, it significantly reduces the load on the upper part of the building and the pressure on the foundation, saving on project costs and transportation energy consumption. The C-shaped steel frame and distributed reinforcing bars work together to ensure the overall rigidity of the floor slab, avoiding flexural deformation and local instability, and meeting the diverse needs of prefabricated buildings.

[0029] In a specific example, the steel keel is one of C-shaped steel, H-shaped steel, or square steel pipe. The cross-sectional height of the steel keel is 120-160mm, the flange width is 50-70mm, and the thickness is 1.5-2.5mm. The reinforcing material is one or more of polypropylene fiber, glass fiber, or steel fiber. The amount of reinforcing material in the foamed concrete 6 is 3%-10%. The specifications of the longitudinally distributed reinforcing bars 4 are 8-12mm × 400-600mm. The diameter of the transversely distributed reinforcing bars 4' is 12-20mm, and the spacing is 4000-5500mm. The high-strength bolts are galvanized bolts of grade 6.8, 8.8, or 10.9. The diameter is 10-18mm, and the diameter of the bolt holes reserved on both wings of the U-shaped connector 7 is 10-18mm. The positioning fasteners include auxiliary positioning bolts 7' and anti-loosening nuts 7''. The auxiliary positioning bolts 7' are used for temporary fixation during the hoisting stage, and the anti-loosening nuts 7'' achieve locking fixation. The top of the U-shaped connector 7 is reserved with a grouting groove. After the node is tightened, micro-expansion waterproof mortar or sealant is injected to form a top seal. Reinforcing ribs are added at the four corners of the overall frame 5 of the floor slab. The thickness of the ribs is the same as that of the web of the steel keel, and the height is the same as that of the keel section height. They are fixed by welding or bolts to improve the shear resistance of the floor slab corners. The corrosion-resistant material is one of PVC, PE, PPR or stainless steel.

[0030] In this specific implementation, the filling layer is foamed concrete, which is poured into the internal cavity of the overall frame and seamlessly fits the inner wall of the C-shaped steel keel. The foamed concrete uses a lightweight and high-strength formula to reduce the self-weight of the floor slab by utilizing its lightweight properties, thereby reducing the load on the building structure and foundation. The foamed concrete also has excellent thermal insulation properties, enabling built-in insulation at the connection points without the need for additional insulation layers. The foamed concrete has pre-reserved channels for laying water, electricity, and heating pipes, avoiding damage to the overall frame by on-site grooving and drilling, and ensuring the integrity of the connection nodes.

[0031] The pouring layer uses high-strength lightweight aggregate instead of ordinary sand and gravel, resulting in lightweight aggregate concrete, which is placed on the upper and lower parts of the overall frame. The pouring height is determined based on the load-bearing capacity of the steel beams to ensure sufficient support for all parts and guarantee their load-bearing capacity. The floor slabs made of lightweight aggregate concrete are formed by the combined action of C-shaped steel joists and distributed reinforcing bars. The lightweight aggregate concrete is tightly connected to the overall frame to improve the integrity and airtightness of the floor slab, while also effectively improving the flatness of the floor surface and significantly increasing the overall stiffness of the floor slab, thereby reducing the occurrence of concrete cracking.

[0032] Both the top and bottom longitudinal reinforcing bars are 10 x 500 mm in diameter and are securely fastened to the C-shaped steel keel of the overall frame 5. The top and bottom transverse reinforcing bars (16 mm in diameter, spaced 4700 mm apart) are inserted inside the longitudinal reinforcing bars and laid in the top and bottom lightweight aggregate concrete respectively. This effectively disperses the stress on the floor slab, inhibits the generation and propagation of concrete cracks, and improves the crack resistance of the floor slab. The water, electricity, and heating pipelines are pre-embedded in dedicated channels inside the foamed concrete, without interfering with the overall frame or U-shaped connectors; the pipelines are made of corrosion-resistant materials (PVC, PE, etc.), and are firmly fixed during pre-embedding to prevent loosening and displacement later. During on-site installation, they are directly connected to the indoor pipeline system without additional construction, ensuring that the connection nodes between the floor slab and the steel beam are not damaged.

[0033] The connecting components include U-shaped connectors, auxiliary positioning bolts, anti-loosening nuts, and thermal insulation gaskets. The U-shaped fastening bolt assembly is adapted to the end fitting grooves of the C-shaped steel keel beams, with 12-16mm diameter bolt holes pre-drilled on both wings. The U-shaped fastening bolt assembly uses 8.8 grade high-strength galvanized bolts (12-14mm diameter). The U-shaped connector passes through the bolt holes of the U-shaped connector and the C-shaped steel keel to achieve vertical fastening. The special-shaped structure of the bolt head engages with the bidirectional groove to form a horizontal limit. The auxiliary positioning bolts are used for temporary fixation during the hoisting stage, and the anti-loosening nuts ensure long-term stability of the connection, constructing a bidirectional constraint system.

[0034] 5%-8% polypropylene fiber can be added to foamed concrete to improve its crack resistance and toughness, and prevent cracking of the filling layer from affecting the stress transfer of the floor slab and steel beam.

[0035] Example 2 To achieve the above objectives, this embodiment also provides a construction method using the aforementioned connection nodes, comprising the following steps: (1) Factory prefabrication stage: Steel keel is processed according to the design dimensions, and after rust removal, it is welded to form an integral frame 5. U-shaped connector fitting groove and bolt holes are reserved; the top and bottom distributed steel bars are fixedly connected to the integral frame 5; foam concrete 6 is poured into the cavity inside the integral frame 5, and water, electricity and heating pipes 3 are pre-embedded at the same time; lightweight aggregate concrete is poured on the top and bottom of the integral frame 5 to complete the prefabrication of single integral composite floor slab 1; at the same time, the U-shaped connector 7 is formed, the thermal insulation pad is installed and the anchor is fixed in the factory to form a modular connection component. (2) On-site installation stage: transport the prefabricated integral composite floor slab 1 to the construction site, hoist it into place, and then connect the open side of the U-shaped connector 7 with the steel keel fitting groove at the end of the floor slab; fine-tune the accuracy of the slab joint by using positioning fasteners and lock it in place; inject sealing material into the grouting groove at the top of the U-shaped connector to complete the slab joint sealing; connect the water, electricity and heating pipelines 3 and debug them; clean the construction site and complete the overall installation.

[0036] It should be noted that the C-shaped steel keel of the overall frame is prefabricated in the factory, and the longitudinal and transverse keels need to be derusted before welding; the overall frame needs to be sealed before pouring foamed concrete to prevent grout leakage; the distributed steel bars need to be straightened before connection to ensure uniform spacing; the U-shaped connectors are finished in the factory by pasting the insulation pad and welding the anchors to achieve modular prefabrication.

[0037] In summary, this invention employs a collaborative design of modular U-shaped connectors, thermal insulation pads, and bidirectional restraint bolts to solve problems such as abrupt changes in structural stiffness, thermal bridging, high precision requirements for joints, poor compatibility of connectors, and susceptibility to pipeline damage in existing lightweight steel foam concrete composite floor slab joints. It integrates structural connection, thermal insulation sealing, and pipeline avoidance functions into one unit, achieving integrated "load-bearing and thermal insulation" at the joints. Furthermore, relying on modular prefabrication and rapid assembly, it significantly improves assembly efficiency.

[0038] This invention (1) fills the gap in existing technology and products; (2) has a comprehensive function of "load-bearing-enclosure-insulation"; (3) has good integrity; when installing components, only the prefabricated floor slabs need to be spliced ​​together to form a complete structural system and maintenance system; (4) has a high degree of on-site assembly: it saves more than half of the working hours compared with the traditional reinforced concrete floor slab construction method, greatly reduces the amount of wet work on the construction site, and can save a lot of timber resources; (5) has a wide range of applications: it is suitable for prefabricated engineering construction projects such as high-rise civil buildings, large public buildings and large-span industrial plants of various heights, which meets the requirements of the national policy of vigorously developing the prefabricated industry.

[0039] This invention integrates modular steel structure connections with thermal insulation and waterproofing functions. It improves the overall integrity of floor slab connections through a composite connection method of U-shaped interlocking, bolt fastening, and anchoring. The thermal insulation pad blocks thermal bridges in the slab joints, ensuring energy-saving effects. The two-way bolt restraint system solves the problem of horizontal lateral displacement. The combination of C-shaped steel keel and lightweight filling material balances thermal insulation and load-bearing performance. The factory prefabrication and on-site assembly mode ensures accurate component dimensions and controllable quality.

[0040] This invention has the following advantages: 1. Modular pre-assembly in the factory ensures the precision and quality of the components; 2. On-site construction only requires dry construction processes such as fitting and bolting, significantly reducing wet work and greatly accelerating the project progress; 3. It achieves an integrated structural form, eliminating the need for cross-operations of many trades and saving a large amount of building materials and labor costs; 4. It adapts to the overall characteristics of light steel-foam concrete composite floor slabs, overcoming the problem of functional incoordination at traditional joints; 5. It achieves organic integration between the insulation layer and the load-bearing layer, meeting the current requirements for green building energy conservation and environmental protection; 6. Comprehensive waterproof protection measures can effectively extend its service life and reduce maintenance costs; 7. Through a reasonable pipe layout, it eliminates structural damage that may be caused by repeated openings.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A modular U-shaped connection node for composite floor slabs, characterized in that, It includes several integral composite floor slabs (1) that are connected to each other by U-shaped connecting components. Each integral composite floor slab (1) includes an integral frame (5), a filling layer, a pouring layer, distributed steel bars and embedded pipelines (3). The components work together to achieve a firm connection between the floor slab and the steel beam and an integrated function of earthquake resistance, load-bearing and thermal insulation. The overall frame (5) is the core load-bearing carrier. It is formed by welding longitudinal and transverse steel keels to form a spatial grid structure. The steel keels are made of high-strength steel. The longitudinal and transverse keels are derusted before welding. The steel beams of the steel keels at both ends of the overall frame (5) are reserved with fitting grooves that are compatible with the U-shaped connectors (7). The groove width matches the flange width of the U-shaped connectors (7). The filling layer is foamed concrete (6), which is poured into the internal cavity of the overall frame (5) and adheres to the inner wall of the steel keel. Reinforcing materials can be selectively added into the foamed concrete (6), and a pipeline pre-embedded channel is reserved inside. The pouring layer is lightweight aggregate concrete, including top lightweight aggregate concrete (2) and bottom lightweight aggregate concrete (2') covering the overall frame (5), and the pouring height is determined according to the load size of the steel beam; The distributed reinforcement includes longitudinal distributed reinforcement (4) and transverse distributed reinforcement (4'). The longitudinal distributed reinforcement (4) is fixedly connected to the steel keel of the overall frame (5), and the transverse distributed reinforcement (4') is inserted inside the longitudinal distributed reinforcement (4). Both are laid in the lightweight aggregate concrete. The U-shaped connection assembly includes a U-shaped connector (7), positioning fasteners and thermal insulation pads. The U-shaped connector (7) has bolt holes on both wings to accommodate high-strength bolts. The head of the high-strength bolts forms an interlocking structure with the slot of the U-shaped connector (7). The positioning fasteners are used for fixing and locking during the installation stage. The thermal insulation pads are placed inside the U-shaped connector (7). The pre-embedded pipeline (3) is made of corrosion-resistant material and is pre-embedded in a special channel of foam concrete (6), without interfering with the overall frame (5) and U-shaped connector (7).

2. The modular U-shaped connection node of the composite floor slab according to claim 1, characterized in that, The steel keel is one of C-shaped steel, H-shaped steel or square steel pipe, and the cross-sectional height of the steel keel is 120-160mm, the flange width is 50-70mm, and the thickness is 1.5-2.5mm.

3. The modular U-shaped connection node of the composite floor slab according to claim 1, characterized in that, The reinforcing material is one or more of polypropylene fiber, glass fiber or steel fiber, and the amount of reinforcing material in foamed concrete (6) is 3%-10%.

4. The modular U-shaped connection node of the composite floor slab according to claim 1, characterized in that, The longitudinally distributed reinforcing bars (4) have a specification of 8-12mm×400-600mm, and the transversely distributed reinforcing bars (4') have a diameter of 12-20mm and a spacing of 4000-5500mm.

5. The modular U-shaped connection node of the composite floor slab according to claim 1, characterized in that, The high-strength bolts are galvanized bolts of grade 6.8, 8.8 or 10.9, with a bolt shank diameter of 10-18mm. The bolt holes reserved on both wings of the U-shaped connector (7) have a diameter of 10-18mm.

6. The modular U-shaped connection node of the composite floor slab according to claim 1, characterized in that, The positioning fasteners include an auxiliary positioning bolt (7') and a lock nut (7''). The auxiliary positioning bolt (7') is used for temporary fixation during the hoisting stage, and the lock nut (7'') is used for locking and fixing.

7. The modular U-shaped connection node of the composite floor slab according to claim 1, characterized in that, The top of the U-shaped connector (7) has a reserved grouting groove. After the joint is tightened, micro-expansion waterproof mortar or sealant is injected to form a top seal.

8. The modular U-shaped connection node of the composite floor slab according to claim 1, characterized in that, Reinforcing ribs are added to the overall frame (5) at the four corners of the floor slab. The thickness of the ribs is the same as that of the web of the steel keel, and the height is the same as that of the keel section. They are fixed by welding or bolts.

9. The modular U-shaped connection node of the composite floor slab according to claim 1, characterized in that, The corrosion-resistant material is one of PVC, PE, PPR or stainless steel.

10. A construction method using any one of the connection nodes described in claims 1-9, characterized in that, Includes the following steps: (1) Factory prefabrication stage: Steel keel is processed according to the design dimensions, and after rust removal, it is welded to form an integral frame (5). U-shaped connector fitting groove and bolt hole are reserved; the top and bottom distributed steel bars are fixedly connected to the integral frame (5); foam concrete (6) is poured into the cavity inside the integral frame (5), and water, electricity and heating pipes (3) are pre-embedded at the same time; lightweight aggregate concrete is poured on the top and bottom of the integral frame (5) to complete the prefabrication of single integral composite floor slab (1); at the same time, the U-shaped connector (7) is formed, the thermal insulation pad is installed and the anchor is fixed in the factory to form a modular connection component; (2) On-site installation stage: transport the prefabricated integral composite floor slab (1) to the construction site, hoist it into place, and then connect the opening side of the U-shaped connector (7) with the steel keel groove at the end of the floor slab; fine-tune the accuracy of the slab joint by positioning fasteners and lock it in place; inject sealing material into the grouting groove at the top of the U-shaped connector to complete the slab joint sealing; connect the water, electricity and heating pipelines (3) and debug them, clean the construction site, and complete the overall installation.

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