Connecting structure of truss reinforced concrete two-way laminated slab bottom plate in dry-type connection

Abstract

The invention relates to a connecting structure of a truss reinforced concrete two-way laminated slab bottom plate in dry connection. The connecting structure comprises a plurality of independent connecting units of the same structure. The plurality of connecting units are arranged at an abutted seam of two adjacent prefabricated bottom plates at intervals so as to fixedly connect the two prefabricated bottom plates; each connecting unit comprises a metal embedded part, and each metal embedded part is integrally embedded in the concrete, close to the splicing edge, of the single prefabricated bottom plate in the prefabrication stage; a through connecting channel is formed in each metal embedded part, and when the abutted seam of the two prefabricated bottom plates is aligned, the connecting channels of the two metal embedded parts belonging to the two prefabricated bottom plates are aligned at the abutted seam; the U-shaped connecting steel bar is used for penetrating through the two connecting channels aligned at the abutted seam from top to bottom, and the two ends of the U-shaped connecting steel bar extend to the positions below the two prefabricated bottom plates; and the fastener module is used for mechanically locking the two ends of the U-shaped connecting steel bar below the prefabricated bottom plate. The device can realize full-dry connection without depending on cast-in-place concrete in any form.

Description

Technical Field

[0001] This invention belongs to the field of building industrialization and prefabricated concrete structure technology, specifically relating to a dry-connected truss reinforced concrete two-way composite slab bottom plate connection structure. Background Technology

[0002] With the rapid development of industrialized construction, precast concrete composite slabs have been widely used in prefabricated buildings due to their advantages such as high production efficiency, fast construction speed, and good integrity. Composite slabs typically consist of a precast base slab in a factory and composite layers cast on-site. The connection quality of the base slab directly affects the integrity, load-bearing performance, and construction efficiency of the floor slab.

[0003] For two-way composite slabs, internal forces need to be transmitted in both directions, thus placing higher demands on the connection at the joints of the base slabs. Traditionally, the connection of the base slabs of two-way composite slabs often adopts an "integral joint" (or "post-cast strip"), which involves reserving a post-cast area at the joint, binding or welding the protruding "stirrups" of adjacent base slabs, and then pouring concrete. While this wet-work connection method can ensure integrity, it has the following significant drawbacks: 1) The presence of "bearded reinforcement" makes the production, stacking and transportation of precast base slabs extremely inconvenient, and easily causes steel bar deformation and concrete impact; 2) On-site construction requires setting up formwork for the post-pouring strip, tying reinforcing bars, and pouring and curing concrete. The process is complicated, the construction period is long, and the quality is greatly affected by on-site operations. 3) The joint area is crowded with steel bars, making it difficult to pour concrete densely, which can easily become a weak link in quality.

[0004] To overcome the problems of traditional wet connections, the industry has explored various approaches. For example, some technical solutions attempt to use pre-reserved grooves with straight-threaded steel bars inside, mechanically connecting them via connectors, but still require pouring concrete into the grooves afterward. Other solutions propose using vertical bolts and horizontal steel plates for connection. While this reduces formwork to some extent, the structure still requires pouring a large area of ​​post-cast concrete above the joint to cover the connector and form an integral load-bearing structure. Essentially, it remains a "semi-dry, semi-wet" or "implicit wet connection," and does not completely eliminate the inherent drawbacks of on-site wet concrete work, long curing periods, and dependence on the quality of post-cast concrete at the connection point. Furthermore, these improved solutions either still require handling exposed steel bar ends or use complex multi-component connection systems, and still fall short in simplifying production and achieving rapid, purely dry installation.

[0005] In short, the existing two-way composite slab bottom plate connection technology cannot get rid of its dependence on on-site poured concrete, resulting in complex construction procedures, long cycles, and difficulty in achieving truly efficient and industrialized fully dry operation. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention provides a dry-connected truss-reinforced concrete two-way composite slab bottom plate connection structure. The technical problem to be solved by this invention is achieved through the following technical solution: This invention provides a dry-connected truss-reinforced concrete two-way composite slab bottom plate connection structure, comprising: multiple independent connection units with identical structures; the multiple connection units are spaced apart at the joint of two adjacent precast bottom plates to fix the two precast bottom plates together; wherein, each precast bottom plate is a truss-reinforced concrete two-way slab. Each connection unit includes: Metal embedded parts, each of which is integrally embedded in the concrete of a single precast base slab near the splicing edge during the prefabrication stage; and, each metal embedded part is provided with a through connecting channel inside, so that when the splicing joint of the two precast base slabs is aligned, the connecting channels of the two metal embedded parts belonging to the two precast base slabs are aligned at the splicing joint. U-shaped connecting steel bars are used to simultaneously pass through two connecting channels aligned at the joint from top to bottom, and their two ends extend to the bottom of the two precast base plates; Fastener module for mechanically locking both ends of the U-shaped connecting steel bars under the precast base plate; The connection node, which is composed of the metal embedded part, the U-shaped connecting steel bar and the fastening component, achieves force transmission at the joint entirely by mechanical locking, without relying on any form of cast-in-place concrete, thus realizing a completely dry connection.

[0007] Compared with the prior art, the beneficial effects of the present invention are as follows: To address the problem that existing bi-directional composite slab bottom plate connection technologies cannot eliminate reliance on on-site concrete pouring, resulting in complex construction procedures, long cycles, and difficulty in achieving truly efficient and industrialized fully dry operations, this invention provides a dry connection structure for truss-reinforced concrete bi-directional composite slab bottom plates. This structure involves pre-embedded metal parts with precise alignment channels at the splicing edges of the precast bottom plates, and a combination of U-shaped connecting steel bars that can penetrate adjacent embedded parts and bottom mechanical fastening units, constructing a fully dry connection node with a completely independent force transmission path, requiring no post-pouring concrete. This structure fundamentally eliminates the need for traditional connecting reinforcement bars and post-pouring strips, making the production, transportation, and stacking of precast bottom plates more convenient. Simultaneously, it enables rapid on-site splicing and a purely dry operation, significantly improving construction efficiency and industrialization levels. Attached Figure Description

[0008] Figure 1This is a schematic diagram of the connection structure of the dry-connected truss reinforced concrete two-way composite slab bottom plate provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the metal embedded part provided in the embodiment of the present invention; Figure 3 This is a structural schematic diagram of the fastener module provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the fit between the fastener module and the U-shaped connecting steel bar provided in the embodiment of the present invention.

[0009] Explanation of icon numbers: 1-Precast base plate; 2-Metal embedded parts; 3-U-shaped connecting steel bars; 4-Connecting steel plates; 5-Nuts; 6-Secondary reinforcing bars; 11-Reinforcing bar truss; 12-Main reinforcing bars; 21-Sleeve-type main body; 22-Recess; 23-Integrated anchoring structure; 231-Anchoring bars. Detailed Implementation

[0010] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0011] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0012] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, disclosure, and appended claims in carrying out the claimed invention. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0013] The connection structure of the bottom plate of the truss reinforced concrete two-way composite slab with dry connection proposed in this invention will now be described in detail with reference to the accompanying drawings.

[0014] Figure 1 This is a schematic diagram of the connection structure of the dry-connected truss reinforced concrete two-way composite slab bottom plate provided in an embodiment of the present invention. Figure 1 As shown, it includes: multiple independent, structurally identical connecting units; multiple connecting units are spaced apart at the joints of two adjacent precast base slabs 1 to fix the two precast base slabs 1 together; wherein, each precast base slab 1 is a truss reinforced concrete two-way slab. Each connection unit includes: Metal embedded parts 2, each metal embedded part 2 is embedded in the concrete of a single precast base plate 1 near the splicing edge during the prefabrication stage; and each metal embedded part 2 is provided with a through connecting channel inside, so that when the splicing joint of two precast base plates 1 is aligned, the connecting channels of the two metal embedded parts 2 belonging to the two precast base plates 1 are aligned at the splicing joint. U-shaped connecting steel bars 3 are used to simultaneously pass through two connecting channels aligned at the joint from top to bottom, and their two ends extend to the bottom of the two precast base plates 1; Fastener module, used to mechanically lock the two ends of U-shaped connecting steel bars 3 under the precast base plate 1; Among them, the connection node, which is composed of metal embedded parts 2, U-shaped connecting steel bars 3 and fastening components, achieves force transmission at the joint entirely by mechanical locking, without relying on any form of cast-in-place concrete, thus realizing a completely dry connection.

[0015] like Figure 1 As shown, the precast base slab 1 is a rectangular slab; each precast base slab 1 contains multiple secondary reinforcing bars 6, which are spaced apart along the width of the precast base slab 1. Furthermore, the sum of the products of the total effective cross-sectional area and the material yield strength of all U-shaped connecting reinforcing bars 3 spanning the same joint is greater than the sum of the products of the total cross-sectional area and the material yield strength of all secondary reinforcing bars 6 cut off by that joint. This is because the secondary reinforcing bars 6 do not protrude from the precast base slab 1 at the joint edge (it should be noted that...). Figure 1 In this case, the two precast base slabs 1 are spliced ​​only in the middle, with their ends placed on beams (the secondary reinforcing bars 6 remain extended at the lap joint with the beams). The tensile force in the secondary load direction at the splice, as well as the tensile stress generated by temperature shrinkage and the overall coordination of the floor slab, needs to be transferred through the connectors across the joint. The U-shaped connecting bars 3, as the main load-bearing components for the joint connection, should not have a load-bearing capacity weaker than the cut-off secondary reinforcing bars 6, thereby avoiding the formation of a weak section at the splice and ensuring the overall load continuity of the composite slab. Therefore, when the material strength grades are the same or the most unfavorable values ​​are used, the principle of equal cross-sectional area can be adopted for control, that is, the total cross-sectional area of ​​the U-shaped connecting bars 3 in all connectors should not be less than the total cross-sectional area of ​​the secondary reinforcing bars 6; when the steel grades are different, the connection load-bearing capacity can also be controlled by adjusting the yield strength.

[0016] To achieve the aforementioned dry connection, the metal embedded part 2, as the core load-bearing and positioning component in this system, has a crucial structural design. The following will combine... Figure 2 Its specific structure will be explained.

[0017] Figure 2 This is a structural schematic diagram of the metal embedded part provided in an embodiment of the present invention. Figure 2 As shown, each metal embedded part 2 includes: The sleeve-type main body 21 is embedded in the concrete of a single precast base plate 1 during the prefabrication stage, and a connecting channel is formed inside the sleeve-type main body 21 for the U-shaped connecting steel bars 3 to pass through. The recess 22 is integrally formed on the bottom of the sleeve-type body 21 and opens downward, and is used to accommodate and hide the fastener module after the connection is completed, thereby keeping the lower surface of the prefabricated base plate 1 flat. An integrated anchoring structure 23 is installed on the outer wall of the sleeve-type main body 21 to enhance the anchoring reliability of the metal embedded part 2 and the surrounding concrete, and to prevent it from being pulled out under stress.

[0018] For example, the sleeve-type main body 21, as the main structural part of the embedded part, is usually made of steel (such as carbon structural steel or low alloy structural steel), preferably a cylindrical sleeve. The outer diameter and wall thickness of the main body are determined according to the stress calculation, and its height is adapted to the thickness of the precast base plate 1. The upper end face is flush with the upper surface of the base plate 1 during the prefabrication stage. A through connecting channel is formed inside, which is a smooth hole with a diameter larger than the diameter of the U-shaped connecting steel bar 3. An installation gap of 2-6mm is usually reserved to facilitate on-site steel bar threading. The core function of the sleeve-type main body 21 is to provide a precise alignment reference for the embedded parts on the adjacent base plates during base plate splicing, and to provide a vertical and smooth through path for the U-shaped connecting steel bar 3, thereby reliably transferring the tensile force borne by the connecting steel bar to the base plate concrete.

[0019] Furthermore, the recess 22 is a rectangular groove, with its length direction perpendicular to the joint and aligned with the length direction of the recess 22 in another precast base plate 1. It should be noted that the recess 22 does not protrude from the precast base plate 1, and its groove depth is less than the thickness of the precast base plate 1. In addition, the main function of the recess 22 is to completely conceal the fastener module within it after the dry connection is completed, ensuring that the lower surface of the precast base plate 1 remains completely flat, without affecting subsequent ceiling installation, decoration, and other processes. It also helps protect the fasteners and reduces the risk of exposed corrosion.

[0020] Finally, the integrated anchoring structure 23 includes multiple anchor bars 231 arranged in a cross shape on the outer wall of the sleeve-type main body 21. These anchor bars 231 are steel bar segments welded to the main body, and their diameter, length, and number are designed according to the pull-out resistance requirements. Their main function is to form a strong mechanical interlocking and gripping force with the concrete when the bottom slab concrete is poured, which greatly enhances the anchoring reliability of the embedded parts in the concrete, and ensures that when the U-shaped connecting steel bar 3 is under tension, the tensile force can be effectively diffused into the surrounding concrete through the anchor bars 231, preventing the embedded parts from slipping or being pulled out, thereby ensuring the stress safety and durability of the entire dry connection node.

[0021] Figure 3 This is a structural schematic diagram of the fastener module provided in an embodiment of the present invention. Figure 4 This is a schematic diagram illustrating the fit between the fastener module and the U-shaped connecting steel bar provided in an embodiment of the present invention. Figure 3-4 As shown, the U-shaped connecting steel bar 3 has external threads at both ends; the fastener module includes a connecting steel plate 4 and a nut 5; wherein, the connecting steel plate 4 is a long strip steel plate with two through holes spaced apart along its length, the position of each through hole corresponding to the protruding position of the U-shaped connecting steel bar 3 after passing through the connecting channel; after the connecting channel and the through hole are passed through one end of the U-shaped connecting steel bar 3 in sequence, the nut 5 is tightened on the threaded section of the U-shaped connecting steel bar 3 to mechanically lock one end of the U-shaped connecting steel bar 3, thereby realizing the connection of the two precast base plates 1.

[0022] Specifically, the connecting steel plate 4 is a long strip of steel plate, and the nut 5 is a standard part whose specifications match the threads of the U-shaped connecting steel bar 3. During installation, the U-shaped connecting steel bar 3 simultaneously passes through the connecting channels of the two aligned metal embedded parts 2 from top to bottom, so that the threaded sections at both ends extend to a predetermined length below the base plate. Then, the two through holes of the connecting steel plate 4 are respectively fitted into the threaded sections at both ends of the U-shaped connecting steel bar 3, so that the connecting steel plate 4 spans across the joint and fits into the recess 22 of the embedded part 2. Finally, the nuts 5 are screwed into the threaded sections at both ends and tightened. By tightening the nuts 5, the connecting steel plate 4 is pressed and fixed, thereby mechanically locking the two ends of the U-shaped connecting steel bar 3 in the reverse direction, forming a rigid node that can transmit tensile force, and realizing a reliable connection between the two precast base plates 1.

[0023] To further prevent loosening, a washer (not shown in the diagram) can be added between the nut 5 and the connecting steel plate 4. After the connection is completed, the entire fastener unit, including the connecting steel plate 4 and the nut 5, is contained within the recess 22 of the metal embedded part 2, ensuring that the lower surface of the precast base plate 1 is flat.

[0024] Here, the U-shaped connecting steel bar 3 preferably uses steel material with the same strength grade as or no lower than that of the bottom plate 1. The diameter d of the steel bar can be determined according to the structural design, for example, d can be 8-16mm. The bend of the U-shaped connecting steel bar 3 preferably adopts a rounded transition, and the radius of curvature of the bent part of the U-shaped connecting steel bar 3 is not less than 4 times the diameter of the U-shaped connecting steel bar 3 itself, preferably 4d-6d, so as to reduce stress concentration at the bend and improve durability. The two ends of the U-shaped connecting steel bar 3 are provided with external thread sections. The thread length should meet the assembly requirements of the thickness of the connecting steel plate 4, the height of the nut 5, and the exposed 2-3 threads. For example, a value in the range of 25-60mm can be selected for each end. If necessary, a washer (not shown) can be set between the nut 5 and the connecting steel plate 4 to improve the pressure surface and anti-loosening performance.

[0025] The above is a structural description of the dry-connected truss reinforced concrete two-way composite slab bottom plate connection structure provided in the embodiments of the present invention. Now, based on the connection structure proposed in this invention, the construction steps are described: (1) Factory Prefabrication Stage: When fabricating the truss-reinforced concrete two-way composite slab base plate 1, the internal steel reinforcement skeleton is tied and fixed simultaneously in the mold, and the metal embedded parts are precisely embedded. Specifically, the main load-bearing steel bars 12 are first laid and fixed, and then the secondary load-bearing steel bars 6 are arranged at intervals along the width of the slab, ensuring that their ends at the splice edge terminate at the predetermined position inside the slab as designed. At the same time, the steel truss 11 is installed to enhance the rigidity and hoisting performance of the base plate. At the designated position at the splice edge, the metal embedded parts 2 are firmly fixed using a special positioning mold, ensuring that the axis of the inner hole (i.e., the connecting channel) of its sleeve-type main body 21 is perpendicular to the splice edge and does not interfere with the steel reinforcement skeleton. Finally, concrete is poured, and after curing, a prefabricated base plate with flat splice edges, no protruding steel bars, and built-in standardized connection interfaces (embedded parts) is obtained.

[0026] (2) On-site hoisting and alignment: Hoist the two precast base plates 1 to be connected to the designed support position. By laying out the positioning lines and possible temporary guiding measures such as inserting guide pins into the embedded holes on one side, make the splicing edges of the two base plates fit tightly together, and ensure that the connection channels of the two metal embedded parts 2 belonging to the two base plates are accurately aligned vertically.

[0027] (3) Through connecting steel bars: The U-shaped connecting steel bars 3 are passed through the connecting channels of the two pre-embedded parts 2 from top to bottom until the parts with external threads at both ends extend below the bottom plate to reach the design length.

[0028] (4) Install and lock the fasteners: Under the precast base plate, insert the two through holes of the long strip connecting steel plate 4 into the threaded sections at both ends of the U-shaped connecting steel bar 3, so that the connecting steel plate 4 spans the joint and is placed in the recess 22 of the embedded part 2. Then, screw nuts 5 into the threaded sections at both ends and tighten them to the specified torque using a wrench, preferably a torque wrench, to press and fix the connecting steel plate 4, thereby completing the mechanical locking of both ends of the U-shaped connecting steel bar 3 and forming a force transmission node.

[0029] (5) Inspection and subsequent procedures: Inspect the connection quality (such as the tightness of the nuts, whether the components are completely hidden in the recesses, etc.). After acceptance, water and electricity pipelines can be laid directly on the top of the integral composite slab, and the upper layer of steel reinforcement can be tied. The composite layer concrete can then be poured as a whole. The entire joint connection process does not require the erection of formwork, tying of connecting steel bars, or any on-site concrete pouring work at the joint, achieving pure and rapid dry construction.

[0030] To address the problem that existing bi-directional composite slab bottom plate connection technologies cannot eliminate reliance on on-site concrete pouring, resulting in complex construction procedures, long cycles, and difficulty in achieving truly efficient and industrialized fully dry operations, this invention provides a dry connection structure for truss-reinforced concrete bi-directional composite slab bottom plates. This structure involves pre-embedded metal parts with precise alignment channels at the splicing edges of the precast bottom plates, and a combination of U-shaped connecting steel bars that can penetrate adjacent embedded parts and bottom mechanical fastening units, constructing a fully dry connection node with a completely independent force transmission path, requiring no post-pouring concrete. This structure fundamentally eliminates the need for traditional connecting reinforcement bars and post-pouring strips, making the production, transportation, and stacking of precast bottom plates more convenient. Simultaneously, it enables rapid on-site splicing and a purely dry operation, significantly improving construction efficiency and industrialization levels.

[0031] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A connecting structure of a dry connected bottom plate of a truss reinforced concrete bidirectional laminated slab, characterized by, The utility model relates to a kind of prefabricated floor connecting unit, including: Independent, structurally identical multiple connecting units; The multiple connecting units are spaced apart at the joint of two adjacent prefabricated floors (1) to fix and connect the two prefabricated floors (1);Wherein, each prefabricated floor (1) is a truss reinforced concrete two-way slab; Each connecting unit includes: Metal embedded parts (2), each metal embedded part (2) is integrally embedded in the concrete near the joint edge of a single prefabricated floor (1) during prefabrication;And each metal embedded part (2) is provided with a connecting channel passing through it, when the joint of the two prefabricated floors (1) is aligned, the connecting channels of the two metal embedded parts (2) belonging to the two prefabricated floors (1) are aligned at the joint; U-shaped connecting steel bars (3) for simultaneously penetrating the two connecting channels aligned at the joint from top to bottom, and the two ends extend below the two prefabricated floors (1); Fastener module for mechanically locking the two ends of the U-shaped connecting steel bar (3) below the prefabricated floor (1); Wherein, the connecting node composed of the metal embedded part (2), the U-shaped connecting steel bar (3) and the fastening assembly realizes the force transmission at the joint completely by mechanical locking, without relying on any form of cast-in-place concrete, thereby realizing full dry connection.

2. The connection structure of the dry-connected bottom plate of the truss reinforced concrete two-way laminated slab according to claim 1, characterized by, Each metal embedded part (2) includes: Sleeve body (21), integrally embedded in the concrete of the single prefabricated floor (1) during prefabrication, the sleeve body (21) forms the connecting channel for the U-shaped connecting steel bar (3) to pass through inside it; Recess (22), integrally formed at the bottom of the sleeve body (21) and downwardly open, for accommodating and hiding the fastener module after connection is completed, thereby keeping the lower surface of the prefabricated floor (1) flat; Integrated anchoring structure (23) provided on the outer wall of the sleeve body (21) for enhancing the anchoring reliability of the metal embedded part (2) and the surrounding concrete, preventing it from being pulled out under stress.

3. The connection structure of the dry-connected bottom plate of the truss reinforced concrete two-way laminated slab according to claim 2, characterized by The connecting channel is a through hole with a diameter larger than the diameter of the U-shaped connecting steel bar (3).

4. The connecting structure of the dry-connected bottom plate of the truss reinforced concrete two-way laminated slab according to claim 2, characterized in that, The integrated anchoring structure (23) includes a plurality of anchoring bars (231) distributed in the shape of a cross on the outer wall of the sleeve body (21).

5. The connecting structure of the dry-connected bottom plate of the truss reinforced concrete two-way laminated slab according to claim 2, characterized in that, The two ends of the U-shaped connecting steel bar (3) are provided with external threads;The fastener module includes a connecting steel plate (4) and a nut (5); Wherein, the connecting steel plate (4) is a long strip-shaped steel plate, which is provided with two through holes at intervals in the length direction, and the position of each through hole corresponds to the position of the U-shaped connecting steel bar (3) after penetrating the connecting channel; After the U-shaped connecting steel bar (3) penetrates the connecting channel and the through hole in sequence at one end, the U-shaped connecting steel bar (3) is mechanically locked at one end by screwing the nut (5) on the threaded section of the U-shaped connecting steel bar (3), thereby realizing the connection of the two prefabricated floors (1).

6. The connection structure of the dry-connected bottom plate of the truss reinforced concrete two-way laminated slab according to claim 5, characterized by When the connection is completed, the connecting steel plate (4) and the nut (5) are accommodated in the recess (22) and do not protrude from the lower surface of the prefabricated bottom plate (1).

7. The connection structure of the dry-connected truss reinforced concrete two-way superimposed slab bottom plate according to claim 1, characterized in that, The curvature radius of the bent portion of the U-shaped connecting steel bar (3) is not less than 4 times the diameter of the U-shaped connecting steel bar (3) itself.

8. The connection structure of the dry-connected truss reinforced concrete two-way composite slab bottom plate according to claim 1, characterized by, A plurality of the secondary stress steel bars (6) are arranged in the monolithic prefabricated bottom plate (1) and are arranged at intervals along the width direction of the prefabricated bottom plate (1).

9. The connection structure of the dry-connected bottom plate of the truss reinforced concrete two-way laminated slab according to claim 8, characterized by, The sum of the products of the total effective cross-sectional area and the material yield strength of all the U-shaped connecting steel bars (3) across the same joint is greater than the sum of the products of the total cross-sectional area and the material yield strength of all the secondary stress steel bars (6) cut off by the joint.

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