A double system connecting structure and construction method for prefabricated waffle slab of composite beam

Abstract

The application relates to a double-system connecting structure and construction method for a combined beam prefabricated waffle plate, which comprises a prefabricated waffle bridge deck plate assembly, a joint connecting assembly and a steel beam assembly. The prefabricated waffle bridge deck plate assembly comprises a prefabricated waffle plate, a steel side mold arranged around the four sides of the prefabricated waffle plate and a plate body longitudinal steel bar assembly. The steel side mold is arranged to form a closed pouring cavity, the inner wall of the steel side mold is welded with a side mold inner steel bar sleeve penetrating through the wall surface, the outer wall of the steel side mold is welded with a side mold outer steel bar sleeve, and the horizontal arrangement interval between the two adjacent side mold outer steel bar sleeves is less than or equal to 200 mm. The joint connecting assembly comprises joint connecting steel bars and joint series connection sleeves. The steel beam assembly comprises a steel beam flange and a comb-shaped PBL connecting piece arranged on the steel beam flange. The joint connecting steel bars simultaneously connect the adjacent prefabricated waffle bridge deck plate assemblies and the comb-shaped PBL connecting piece, serve as the shared force transmission component of the plate-plate connecting system and the plate-beam connecting system, and form a plate-plate-beam double-system cooperative force transmission path.

Description

Technical Field

[0001] This application relates to the field of bridge engineering technology, and in particular to a dual-system connection structure and construction method for precast waffle slabs in composite beams. Background Technology

[0002] Precast waffle bridge panels are integrally cast using a thin top plate and orthogonally arranged longitudinal and transverse stiffening ribs at the bottom, forming a spatially coordinated force-bearing structural system. They possess core technological advantages such as lightweight, high overall structural rigidity, high level of industrialized prefabrication, and convenient on-site assembly. They have now become the core panel component for the rapid construction of steel-concrete composite beam bridges and are widely used in various engineering scenarios such as urban expressways, cross-river and cross-sea super-large bridges, and reinforcement and renovation of existing old bridges. They are the mainstream selected component for prefabricated composite bridge projects.

[0003] However, traditional precast waffle slabs for steel-concrete composite beams employ two independent structures: one for splicing between slabs and the other for connecting the slab to the main steel beam. These two structural arrangements are prone to interference, resulting in multiple technical defects. Firstly, the distribution of top and bottom connecting reinforcement bars at the splice joints between adjacent precast waffle slabs is uneven, with the spacing of the bottom connecting reinforcement bars exceeding 600mm, far exceeding the maximum spacing limit specified in GB 50917-2013 (8 times the length of the reinforcement bars above the comb-type PBL connector and ≤600mm). Existing solutions (such as CN108691272A) are designed for ordinary solid precast slabs, allowing for flexible arrangement of the spacing between the reinforcing bars within the slab. However, the bottom reinforcing bars of waffle slabs are constrained by the rib spacing (60-100cm), requiring continuous reinforcing bars to be placed at the bottom of the ribs. This inevitably results in a spacing of over 600mm for the bottom transverse connecting reinforcing bars, leading to poor stress continuity. Secondly, there is a spatial conflict between the conventional main beam connection structure and the precast slab joint reinforcing bars. Traditional vertical perforated PBLs lack a sliding guide structure, making it difficult to hoist and position the precast waffle slabs. Furthermore, the inter-slab joint reinforcing bars are difficult to embed smoothly into the main beam comb-tooth PBL connectors. Thirdly, the precast templates only serve a forming function and do not have a reinforcing bar positioning function. Adding additional positioning fixtures increases the precast process, and the comb-tooth PBL connectors do not participate in permanent stress, resulting in insufficient overall bridge stiffness and making it difficult to meet the stress and assembly construction requirements of large-span lightweight composite beams. Summary of the Invention

[0004] This application provides a dual-system connection structure and construction method for precast waffle slabs in composite beams, which can solve the problems in related technologies where the reinforcement density in the wet joint area of ​​precast waffle bridge deck is difficult to meet the specifications and there is spatial interference with the comb-type PBL connectors of the slab and beam.

[0005] In a first aspect, embodiments of this application provide a dual-system connection structure for precast waffle slabs in composite beams, comprising: a precast waffle bridge deck assembly, a joint connection assembly, and a steel beam assembly. The precast waffle bridge deck assembly includes a precast waffle slab, steel side molds surrounding the precast waffle slab, and a continuous steel reinforcement assembly for the slab. The steel side molds form a closed casting cavity, with inner wall welded with a through-wall steel reinforcement sleeve and outer wall welded with an outer steel reinforcement sleeve. The continuous steel reinforcement assembly passes through the inner steel reinforcement sleeve of the side mold, and the horizontal spacing between two adjacent outer steel reinforcement sleeves is less than or equal to 200 mm. The joint connection assembly includes joint connecting steel bars and joint tandem sleeves. The joint connecting steel bars pass through the side mold... The steel beam assembly includes a steel beam flange and a comb-shaped PBL connector disposed on the steel beam flange. The comb-shaped PBL connector has an inclined guiding structure. Adjacent precast waffle bridge panel assemblies are connected by joint reinforcing bars that pass through the corresponding side formwork external reinforcing bar sleeves and are joined together via the joint series sleeves to form a slab-slab connection system. The joint connecting reinforcing bars pass through the inclined guiding structure of the comb-shaped PBL connector to form a slab-beam connection system. The joint connecting reinforcing bars simultaneously connect adjacent precast waffle bridge panel assemblies with the comb-shaped PBL connector, constituting a shared force transmission component for both the slab-slab connection system and the slab-beam connection system, forming a slab-slab-slab-beam dual-system collaborative force transmission path.

[0006] In conjunction with the first aspect, in the implementation method, the inner steel reinforcement sleeve of the side formwork includes a top inner sleeve and a bottom inner sleeve, wherein the top inner sleeve is located at the top of the bottom inner sleeve. The top inner sleeves on the opposite side walls of the steel side mold are correspondingly arranged, and the bottom inner sleeves on the opposite side walls of the steel side mold are correspondingly arranged. The steel side formwork has a rebar positioning hole corresponding to the position of the continuous rebar assembly of the plate. The rebar sleeve inside the side formwork is welded to the rebar positioning hole. The continuous rebar assembly of the plate passes through the rebar positioning hole and the rebar sleeve inside the side formwork.

[0007] In conjunction with the first aspect, in the implementation method, the continuous steel reinforcement assembly of the plate body includes: A bottom continuous steel reinforcement assembly, comprising transverse bottom reinforcement and longitudinal bottom reinforcement, wherein both ends of the transverse bottom reinforcement and the longitudinal bottom reinforcement are inserted into the corresponding bottom inner sleeve; A top-level continuous steel reinforcement assembly, comprising top-level longitudinal steel bars and top-level transverse steel bars, wherein the top-level longitudinal steel bars and top-level transverse steel bars are both inserted into the corresponding top-level inner sleeve.

[0008] In conjunction with the first aspect, in the implementation method, the joint connecting reinforcement includes bottom joint longitudinal reinforcement and bottom joint transverse reinforcement. The bottom joint transverse reinforcement passes through the side formwork outer reinforcement sleeve, and the horizontal spacing between two adjacent bottom joint transverse reinforcements is less than or equal to 200mm.

[0009] In conjunction with the first aspect, in the implementation method, one end of the joint connecting steel bar is inserted into the outer steel bar sleeve of the side formwork, and the other end is connected to the joint connecting steel bar of the adjacent precast waffle bridge panel assembly through the joint series sleeve, so as to form a continuous force transmission structure between the panels.

[0010] In conjunction with the first aspect, in the implementation, the inner steel reinforcement sleeve of the side mold is welded to the inner wall of the steel side mold, and one end of the inner steel reinforcement sleeve of the side mold extends into the precast waffle slab. The continuous steel reinforcement assembly of the slab is inserted through the inner steel reinforcement sleeve of the side mold and anchored in the precast waffle slab.

[0011] In conjunction with the first aspect, in the embodiment, the comb-shaped PBL connector is welded to the flange of the steel beam and is provided with inclined guide teeth. The inclined guide teeth have an inclination angle of 15° to 60° to form an inclined guide structure on the flange of the steel beam. The inclined guide comb teeth are positioned to match the positions of the joint connecting steel bars and are evenly arranged at a set interval. The joint connecting steel bar slides into the comb-shaped PBL connector along the inclined surface of the inclined guide comb teeth.

[0012] In conjunction with the first aspect, in the implementation method, the inclined opening direction of the comb-shaped PBL connector faces the hoisting and positioning direction of the prefabricated waffle bridge panel assembly. The inclined opening of the comb-type PBL connector forms a wedge-shaped interlocking structure after it is connected to the joint connecting steel bar.

[0013] Secondly, embodiments of this application provide a construction method for a dual-system connection structure for precast waffle slabs of composite beams, used to construct the dual-system connection structure for precast waffle slabs of composite beams as described above, comprising: A steel support frame, a steel bottom mold panel, and an array-type ribbed forming mold box are laid on the bottom mold platform, and a release agent is applied to the mold box to complete the installation of the bottom mold structure. The mold box is a frustum shape with the small end facing upward. A steel side mold is installed on the bottom mold structure to form a closed casting cavity, and an inner steel reinforcement sleeve and an outer steel reinforcement sleeve are installed on the steel side mold. The continuous steel reinforcement assembly of the slab is inserted through the steel reinforcement sleeve inside the side formwork; By passing the external steel sleeve of the side formwork through the joint connection steel bars, a closely spaced joint reinforcement is formed; Concrete is poured into a closed casting cavity and steam-cured to form an integrated precast steel-concrete waffle bridge deck assembly with steel side molds. The integrated precast steel-concrete bridge deck assembly was hoisted onto the steel beam assembly. Adjacent waffle slabs are connected to the reinforcing bars via a series of joint sleeves at the joint; The joint connecting steel bars slide in along the inclined guide structure of the comb-shaped PBL connector to complete the slab-beam connection.

[0014] In conjunction with the second aspect, in the implementation method, the integrated steel-concrete precast waffle bridge deck assembly is formed by casting together steel side molds, inner steel sleeves of the side molds, outer steel sleeves of the side molds, continuous steel reinforcement assemblies of the slab, joint connecting steel reinforcement, and concrete. The concrete forms an integral whole with the steel side molds through the embedding and interlocking action of the inner steel sleeves of the side molds. When demolding, the steel side molds and the precast waffle slabs are separated from the bottom mold structure together. The joint connecting steel bars and the slab's full-length steel bar assembly form a continuous stress-bearing steel mesh structure; The center spacing of the side formwork outer steel bar sleeves is determined according to the waffle plate rib spacing. When the rib spacing is 60~100cm, no less than 3 side formwork outer steel bar sleeves are arranged between every two adjacent ribs, so that the spacing of the transverse steel bars of the bottom joint is set in the range of 150~200mm. The welded joints of the inner and outer steel reinforcement sleeves of the side formwork and the steel side formwork adopt a double-sided welding process, and the welding thickness is greater than or equal to the minimum value between the sleeve wall thickness and the steel side formwork thickness.

[0015] The beneficial effects of the technical solutions provided in this application include: This application provides a dual-system connection structure and construction method for precast waffle slabs in composite beams. A frame structure is formed by enclosing the precast waffle slab within a steel side formwork, creating a closed casting cavity. This allows the precast waffle slab to be formed within a confined space, with a tight enveloping fit between the steel side formwork and the precast waffle slab. Multiple through-wall steel reinforcement sleeves are provided on the inner wall of the steel side formwork. The continuous steel reinforcement assembly of the slab passes through these sleeves and is embedded within the precast waffle slab. The sleeves limit the movement of the reinforcement, achieving positioning and fixation of the continuous steel reinforcement assembly at the edge of the precast waffle slab, ensuring… This design ensures reliable connection between the reinforcing bars and the steel side formwork. Simultaneously, the outer wall of the steel side formwork is equipped with multiple external reinforcing bar sleeves for the insertion of joint connection components. Standardized external connection interfaces are constructed during the prefabrication stage, allowing the joint connection components to be installed based on preset positions. Furthermore, the insertion position of the joint connection components is no longer limited by the spacing of the internal ribs of the prefabricated waffle slab, but can be flexibly adjusted according to the arrangement of the sleeves on the steel side formwork. This enables a closer, denser arrangement in the wet joint area, enhancing the lateral restraint on the joint concrete and providing a structural basis for meeting the reinforcement limits specified in the code.

[0016] The combined use of inner and outer sleeves of the steel side formwork creates a collaborative force-bearing system among the reinforcing bars, steel side formwork, and precast waffle slab. The steel side formwork, as a permanent structural component, participates in the load-bearing process, improving the overall structural performance and rigidity of the component. It also enables the steel side formwork to function as a reinforcing bar positioning mold during the casting process, ensuring the positional accuracy of the continuous reinforcing bar components and joint connection components relative to the precast waffle slab, and avoiding subsequent installation conflicts caused by reinforcing bar position deviations. A dual-system synergistic force transmission mechanism is adopted, combining tandem sleeve plate-to-plate connections and inclined open comb-tooth PBL plate-to-beam connections. Structural coupling and mechanical synergy are achieved through an integrated side-formwork sleeve system. In terms of structural coupling, the joint connecting reinforcement bars passing through the outer side-formwork sleeves serve simultaneously as the connection end of the tandem sleeves and the sliding end of the comb-tooth PBL connectors. This allows the same batch of reinforcement bars to transmit longitudinal tensile and compressive forces at the plate-to-plate interface through the tandem sleeves, and to transmit interfacial shear forces at the plate-to-beam interface through the comb-tooth PBL connectors, achieving a "dual-purpose reinforcement" structural integration. In terms of mechanical synergy, because the horizontal spacing between adjacent outer side-formwork sleeves is less than or equal to 200mm, the spacing of the joint connecting reinforcement bars is controlled within a dense range. This design provides dense lateral restraint to the concrete in the joint area, reducing crack width and maintaining concrete integrity. Consequently, the concrete tenons within the holes of the comb-shaped PBL connector receive better lateral support, enhancing the compressive strength of the concrete tenons and improving the shear capacity of the PBL. Conversely, the comb-shaped PBL connector provides reliable shear force transfer at the plate-beam interface, effectively transferring longitudinal shear force in the joint area to the steel beam flange. This results in a more uniform shear force distribution in the joint area, reducing the risk of joint cracking. The two systems form a positive mechanical feedback loop. In terms of construction coordination, based on the inclined guiding structure of the comb-shaped PBL connector, the plate-to-plate tandem sleeve butt joint and the plate-beam comb-tooth sliding engagement can be completed in the same hoisting process without secondary adjustments, achieving simultaneous implementation of plate-to-plate and plate-beam connections. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of a combined bridge structure provided in an embodiment of this application; Figure 2 A schematic diagram of a combined bridge structure provided in an embodiment of this application; Figure 3 This is a schematic diagram of the bottom mold structure provided in an embodiment of this application; Figure 4 A schematic diagram of a steel side mold provided in an embodiment of this application; Figure 5 This is a schematic diagram of the bottom continuous steel bar assembly provided in an embodiment of this application; Figure 6 A schematic diagram of the top-layer continuous steel reinforcement assembly provided in the embodiments of this application; Figure 7 This is a schematic diagram of the joint connection reinforcement provided in the embodiments of this application; Figure 8 A schematic diagram of a waffle bridge panel assembly provided in an embodiment of this application; Figure 9 A schematic diagram of a waffle bridge panel assembly provided in an embodiment of this application; Figure 10 A schematic diagram of a steel beam assembly provided in an embodiment of this application.

[0019] In the diagram: 1. Bottom mold structure; 10. Steel bottom mold panel; 11. Mold box; 2. Steel side formwork; 20. Inner steel reinforcement sleeve of side formwork; 21. Outer steel reinforcement sleeve of side formwork; 3. Continuous reinforcement assembly for the slab; 30. Continuous reinforcement assembly for the bottom layer; 300. Transverse bottom layer reinforcement; 301. Longitudinal bottom layer reinforcement; 31. Continuous reinforcement assembly for the top layer; 310. Longitudinal reinforcement for the top layer; 311. Transverse reinforcement for the top layer; 4. Precast waffle slabs; 5. Steel beam assembly; 50. Steel beam flange; 51. Comb-type PBL connector; 6. Joint connection assembly; 60. Joint connection reinforcement; 600. Longitudinal reinforcement of bottom joint; 601. Transverse reinforcement of bottom joint; 61. Joint tandem sleeve. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] This application provides a dual-system connection structure and construction method for precast waffle slabs in composite beams, which can solve the problems in related technologies where the reinforcement density in the wet joint area of ​​precast waffle bridge deck is difficult to meet the specifications and there is spatial interference with the comb-type PBL connectors of the slab and beam.

[0022] In a first aspect, embodiments of this application provide a dual-system connection structure for precast waffle slabs in composite beams, comprising: a precast waffle bridge deck assembly, a joint connection assembly 6, and a steel beam assembly 5. The precast waffle bridge deck assembly includes a precast waffle slab 4, steel side molds 2 surrounding the precast waffle slab 4, and a continuous steel reinforcement assembly 3. The steel side molds 2 form a closed casting cavity, with inner wall welded with a through-wall inner steel reinforcement sleeve 20 and outer wall welded with an outer steel reinforcement sleeve 21. The continuous steel reinforcement assembly 3 passes through the inner steel reinforcement sleeve 20 of the side mold, and the horizontal spacing between two adjacent outer steel reinforcement sleeves 21 is less than or equal to 200 mm. The joint connection assembly 6 includes joint connecting steel bars 60 and joint tandem sleeves 61. The joint connecting steel bars 60 pass through... Inside the outer steel reinforcement sleeve 21 of the side formwork; the steel beam assembly 5 includes a steel beam flange 50 and a comb-shaped PBL connector 51 disposed on the steel beam flange 50. The comb-shaped PBL connector 51 has an inclined guiding structure; wherein, two adjacent precast waffle bridge panel assemblies are connected by joint connecting steel bars 60 passing through the corresponding outer steel reinforcement sleeve 21 of the side formwork, and are connected by joint series sleeves 61 to form a plate-plate connection system; the joint connecting steel bars 60 pass through the inclined guiding structure of the comb-shaped PBL connector 51 to form a plate-beam connection system; the joint connecting steel bars 60 simultaneously connect adjacent precast waffle bridge panel assemblies and the comb-shaped PBL connector 51, constituting a shared force transmission component for the plate-plate connection system and the plate-beam connection system, forming a plate-plate-plate-beam dual-system collaborative force transmission path.

[0023] This application utilizes a steel side mold 2 to form a frame structure and an internal closed casting cavity, enabling the precast waffle slab 4 to be formed within a confined space. A tight, enveloping fit is established between the steel side mold 2 and the precast waffle slab 4. Multiple through-wall reinforcing bar sleeves 20 are provided on the inner wall of the steel side mold 2. The continuous reinforcing bar assembly 3 of the slab passes through the reinforcing bar sleeves 20 and is embedded within the precast waffle slab 4. The sleeves limit the movement of the reinforcing bars, thus achieving the positioning and fixation of the continuous reinforcing bar assembly 3 at the edge of the precast waffle slab 4, ensuring the connection between the reinforcing bars and the steel side mold 2. Reliability; at the same time, the outer wall of the steel side formwork 2 is provided with multiple side formwork outer steel sleeves 21 for the joint connection components 6 to pass through. Standardized external connection interfaces are constructed in the prefabrication stage, which allows the joint connection components 6 to be installed based on preset positions. Moreover, the position of the joint connection components 6 is no longer limited by the spacing of the internal ribs of the prefabricated waffle slab 4, but can be flexibly adjusted according to the arrangement of sleeves on the steel side formwork 2. This enables a closer arrangement of smaller spacing in the wet joint area, enhances the lateral restraint capacity of the joint concrete, and provides a structural basis for meeting the reinforcement limit of the specification.

[0024] The combined use of the inner and outer sleeves of the steel side formwork 2 creates a collaborative force-bearing system among the reinforcing bars, the steel side formwork 2, and the precast waffle slab 4. The steel side formwork 2, as a permanent structural component, participates in the force-bearing process, improving the overall structural performance and rigidity of the component. It also enables the steel side formwork 2 to function as a reinforcing bar positioning mold during the casting process, ensuring the positional accuracy of the continuous reinforcing bar component 3 and the joint connection component 6 relative to the precast waffle slab 4, and avoiding subsequent installation conflicts caused by the deviation of the reinforcing bar position.

[0025] A dual-system synergistic force transmission mechanism is adopted, combining tandem sleeve plate-to-plate connections and inclined open comb-type PBL plate-to-beam connections. Structural coupling and mechanical synergy are achieved through an integrated sleeve system for the steel side formwork 2. In terms of structural coupling, the joint connecting steel bars 60 passing through the outer steel sleeves 21 of the side formwork serve simultaneously as the connection end of the tandem sleeves 61 and the sliding end of the comb-type PBL connector 51. This allows the same batch of steel bars to transmit longitudinal tensile and compressive forces at the plate-to-plate interface through the tandem sleeves 61, and at the plate-to-beam interface through the comb-type PBL connector 51, achieving a "dual-purpose" structural integration. In terms of mechanical synergy, since the horizontal spacing between adjacent outer steel sleeves 21 of the side formwork is less than or equal to 200mm, the spacing of the joint connecting steel bars 60 is controlled within... Within a dense area, the concrete in the joint zone receives dense lateral restraint, reducing crack width and maintaining concrete integrity. This, in turn, provides better lateral support to the concrete tenon within the comb-shaped PBL connector 51, enhancing the tenon's compressive strength and improving the PBL's shear capacity. Conversely, the comb-shaped PBL connector 51 provides reliable shear force transfer at the plate-beam interface, effectively transferring longitudinal shear force in the joint zone to the steel beam flange 50. This results in a more uniform shear force distribution in the joint zone, reducing the risk of joint cracking, and creating a positive mechanical feedback between the two systems. In terms of construction coordination, based on the inclined guiding structure of the comb-shaped PBL connector 51, the plate-to-plate sleeve connection and the plate-beam comb-tooth sliding engagement can be completed in the same hoisting process without secondary adjustments, achieving simultaneous implementation of plate-to-plate and plate-beam connections.

[0026] Steel side molds 2 are set around the precast waffle slab 4, forming a frame structure to define the forming boundary of the precast waffle slab 4. The steel side molds 2 are made of steel to meet the requirements of sleeve welding process and overall structural rigidity. Steel side molds 2 have rebar positioning holes corresponding to the positions of the continuous rebar assembly 3 of the slab. Rebar sleeves 20 inside the side mold are welded to the rebar positioning holes on the inner side of the steel side mold 2, and the welded areas are sealed to prevent grout leakage. The continuous rebar assembly 3 of the slab passes through the rebar positioning holes and is embedded in the rebar sleeves 20 inside the side mold, so that the rebar skeleton is positioned by the steel side mold 2 before concrete pouring, ensuring that the spatial distribution of the stressed rebar inside the slab meets the design requirements. The steel side molds 2, as a permanent structural part, are retained at the edge of the precast waffle slab 4, working together with the concrete to enhance the constraint capacity of the slab edge. Furthermore, the rebar sleeves 20 inside the side mold are distributed laterally along the steel side mold 2, adapting to the grid-like arrangement of the rebar inside the slab, ensuring the anchorage stability of the continuous rebar after the concrete has cured.

[0027] Steel side formwork 2 has external reinforcing bar sleeves 21 welded transversely at predetermined intervals on its outer side. These sleeves are used for the joint connection assembly 6 to pass through, establishing a connection channel between adjacent panels. The horizontal spacing between two adjacent external reinforcing bar sleeves 21 is less than or equal to a preset threshold; in this embodiment, the preset threshold is 200mm. The dense arrangement of the external reinforcing bar sleeves 21 constrains the distribution density of the joint connection reinforcement 60, preventing insufficient crack resistance due to excessive spacing of the bottom reinforcement. The axis of the external reinforcing bar sleeves 21 is aligned with the extension direction of the joint connection assembly 6, ensuring that the joint connection reinforcement 60 can be smoothly inserted and cooperate with the steel beam assembly 5, providing a stable support base for the mechanical transmission at the joint, ensuring the continuity of the connection interface, and meeting the structural requirements for supplementary reinforcement at the joint, enabling the joint connection assembly 6 to effectively transmit force across the panel gap.

[0028] It should also be noted that, in this embodiment, the inner steel reinforcement sleeve 20 of the side formwork is welded to the inner wall of the steel side formwork 2, and one end of the inner steel reinforcement sleeve 20 extends into the precast waffle slab 4. The continuous steel reinforcement assembly 3 of the slab passes through the inner steel reinforcement sleeve 20 of the side formwork and is anchored in the precast waffle slab 4. That is to say, the steel side formwork 2 and the precast waffle slab 4 form a steel-concrete integrated structure through the interlocking action of the inner steel reinforcement sleeve 20 of the side formwork and the continuous steel reinforcement assembly 3 of the slab. The steel side formwork 2 is made of steel, and the inner steel reinforcement sleeve 20 of the side formwork is welded and fixed along the inner wall of the steel side formwork 2. The top continuous steel reinforcement assembly 31 and the bottom continuous steel reinforcement assembly 30 of the slab are respectively inserted into the inner steel reinforcement sleeve 20 of the side formwork at the corresponding positions. After the concrete has solidified, the cement slurry fills the gap between the sleeve and the reinforcing steel, as well as the rough surface of the inner wall of the steel side formwork 2, forming a dual connection interface of mechanical interlocking and bonding force, ensuring no relative slippage between the steel side formwork 2 and the precast waffle slab 4. The steel side formwork 2, as a permanent structural component of the precast waffle slab 4 rather than a temporary formwork, has an anti-corrosion coating on its outer surface to adapt to the bridge's external service environment, and its own rigidity provides additional constraint on the slab edges. During the demolding process after prefabrication, the bonding force between the steel side formwork 2 and the precast waffle slab 4 is greater than the adsorption force between the steel side formwork 2 and the bottom formwork structure. This allows the steel side formwork 2 and the precast waffle slab 4 to detach from the bottom formwork structure simultaneously during demolding. The steel side formwork 2 remains at the edge of the slab as a rigid reference surface for subsequent hoisting and connection, avoiding edge concrete damage and dimensional deviations caused by the removal of temporary formwork.

[0029] The placement and spacing of the side formwork outer reinforcement sleeves 21 are determined based on the position and spacing of the additional joint connecting reinforcement 60 at the joint. This ensures that the sleeve axis coincides with the extension path of the joint connecting reinforcement 60, and that the spacing meets the reinforcement limit requirements of the specifications, avoiding a decrease in crack resistance due to excessively sparse reinforcement distribution. One end of the joint connecting reinforcement 60 is inserted into the side formwork outer reinforcement sleeve 21 and fixed by threading or welding. The other end extends to a pre-reserved connection section outside the slab, and is connected to the joint connecting reinforcement 60 of the adjacent precast waffle slab 4 via the joint tandem sleeve 61. The joint tandem sleeve 61 is fitted onto the ends of the two butted joint connecting reinforcement 60s, and has internal connecting threads or grouting material to form a rigid connection node, ensuring effective stress transfer in the reinforcement. Through this connection structure, the tensile or shear force generated by the load is transmitted to the outer steel sleeve 21 of the side formwork via the joint connecting steel bar 60, and then distributed to the interior of the steel side formwork 2 and the precast waffle slab 4, realizing continuous force transmission between adjacent precast waffle bridge deck components, ensuring the overall stiffness and stress continuity of the bridge structure at the joint, avoiding structural failure caused by stress concentration at the joint, and enabling multiple precast slabs to form a synergistic overall bridge deck system after splicing.

[0030] Based on the above embodiments, in this embodiment, the multiple inner steel reinforcement sleeves 20 of the side formwork include a top inner sleeve and a bottom inner sleeve. The top inner sleeve is located on top of the bottom inner sleeve. The two are arranged in layers in the vertical direction of the steel side formwork 2 to respectively adapt to the top continuous steel reinforcement assembly 31 and the bottom continuous steel reinforcement assembly 30 in the slab continuous steel reinforcement assembly 3. The bottom inner sleeve is used to constrain the bottom continuous steel reinforcement assembly 30, and the top inner sleeve is used to constrain the top continuous steel reinforcement assembly 31. Through the layered positioning of the sleeves, the steel reinforcement skeleton forms a stable spatial grid structure before concrete pouring, ensuring the spatial position accuracy of the upper and lower layers of steel reinforcement.

[0031] The top inner sleeves on the opposite side walls of the steel side formwork 2 are correspondingly arranged, and the bottom inner sleeves on the opposite side walls of the steel side formwork 2 are correspondingly arranged, that is, the axes of the sleeves on the opposite side walls are on the same horizontal straight line. This corresponding arrangement ensures that the full-length steel reinforcement assembly 3 can pass horizontally through the steel side formwork 2 without bending, ensuring the straightness and stress performance of the steel reinforcement inside the precast waffle slab 4, while maintaining the structural symmetry on both sides of the steel side formwork 2, and avoiding deformation of the steel side formwork 2 under the lateral pressure of concrete due to uneven resistance of steel reinforcement insertion.

[0032] In this embodiment, the continuous steel reinforcement assembly 3 includes a bottom continuous steel reinforcement assembly 30 and a top continuous steel reinforcement assembly 31, which are arranged in layers along the thickness direction of the precast waffle slab 4. The bottom continuous steel reinforcement assembly 30 is located in the lower region of the precast waffle slab 4, and the top continuous steel reinforcement assembly 31 is located in the upper region of the precast waffle slab 4. This vertical layered layout corresponds to the vertical distribution of the steel reinforcement sleeves 20 in the upper side mold of the steel side mold 2, so that the steel reinforcement skeleton forms a stable spatial frame structure before pouring, which adapts to the stress characteristics of the waffle bridge deck.

[0033] The bottom continuous reinforcing bar assembly 30 includes transverse bottom reinforcing bars 300 and longitudinal bottom reinforcing bars 301. Both ends of the transverse bottom reinforcing bars 300 and the longitudinal bottom reinforcing bars 301 are inserted into corresponding bottom inner sleeves. The bottom inner sleeves are the portion of the side formwork inner reinforcing bar sleeves 20 located at the lower part of the steel side formwork 2. The bottom inner sleeves are welded transversely at intervals along the steel side formwork 2, providing support bases for the transverse bottom reinforcing bars 300. The longitudinal bottom reinforcing bars 301 pass through or are connected to the sleeves at the ends of the steel side formwork 2. By constraining the ends of the reinforcing bars through the sleeves, the horizontal and vertical displacement of the reinforcing bars during concrete vibration is limited, ensuring the flatness of the bottom reinforcing mesh and the uniformity of the protective layer thickness, and preventing the reinforcing bars from directly contacting the inner wall of the steel side formwork 2.

[0034] The top-layer continuous reinforcing steel assembly 31 includes top-layer longitudinal reinforcing bars 310 and top-layer transverse reinforcing bars 311. Both the top-layer longitudinal reinforcing bars 310 and the top-layer transverse reinforcing bars 311 are threaded into corresponding top-layer inner sleeves. The top-layer inner sleeve is the portion of the side formwork inner reinforcing bar sleeve 20 located above the steel side formwork 2. The top-layer inner sleeve is located at the top of the bottom-layer inner sleeve, and the two maintain a preset vertical distance to define the effective load-bearing height of the slab. After the top-layer reinforcing bars are positioned by the top-layer inner sleeve, they form a double-layer reinforcement system with the bottom-layer reinforcing bars, enhancing the bending stiffness of the precast waffle slab 4 and ensuring the precise position of the reinforcing bar ends, facilitating subsequent alignment and connection with the joint connection assembly 6 or external structure.

[0035] One end of the joint connecting steel bar 60 is inserted into the outer steel bar sleeve 21 of the side formwork, and the other end is connected to the joint connecting steel bar 60 of the adjacent precast waffle bridge panel component through the joint series sleeve 61 to form a continuous force transmission structure between the panels. The joint series sleeve 61 is sleeved on the ends of the two connected joint connecting steel bars 60. The sleeve is provided with connecting threads or filled with grout to form a rigid mechanical connection node, ensuring that the steel bar stress is not interrupted at the joint and that the connection part has sufficient tensile and shear strength. The joint connecting steel bars 60 of adjacent precast waffle bridge decks are connected by joint series sleeves 61 to form a continuous steel bar link. The joint connecting steel bars 60 include the bottom joint longitudinal steel bars 600 and the bottom joint transverse steel bars 601. The bottom joint transverse steel bars 601 are inserted through the side formwork outer steel bar sleeves 21. The horizontal spacing between adjacent side formwork outer steel bar sleeves 21 is ≤200mm, that is, the horizontal spacing between two adjacent bottom joint transverse steel bars 601 is less than or equal to 200mm. This spacing value is set according to the structural reinforcement specification. The distribution density of the joint connecting steel bars 60 is constrained by the closely arranged side formwork outer steel bar sleeves 21 to ensure the uniformity of the steel bars in the joint area.

[0036] The aforementioned spacing is designed to compensate for insufficient bottom reinforcement caused by a waffle rib spacing >600mm, ensuring that the reinforcement ratio at the joint meets the limits for crack control and bearing capacity specified in bridge structural codes, and preventing early cracking or stress concentration at the concrete joint due to sparse reinforcement distribution. The placement and spacing of the outer reinforcement sleeves 21 of the side formwork are determined based on the position and spacing of the additional joint connecting reinforcement 60 at the joint, ensuring that the reinforcement axis coincides with the sleeve axis, and avoiding eccentric stress or installation interference during reinforcement installation. One end of the joint connecting steel bar 60 is inserted into the outer steel bar sleeve 21 of the side formwork, and the other end is connected to the joint connecting steel bar 60 of the adjacent precast waffle bridge panel component through the joint series sleeve 61, so as to realize continuous force transmission between the panels. The load is transferred to the joint series sleeve 61 through the joint connecting steel bar 60, and then distributed to the precast waffle slab 4 and steel side formwork 2 of the adjacent panel, ensuring the overall rigidity and stress continuity of the structure at the joint, so that multiple precast panels can form a synergistic stress-bearing overall bridge deck system after splicing, improving the durability and safety of the structure during operation.

[0037] In addition, the continuous steel reinforcement assembly 3 includes a bottom continuous steel reinforcement assembly 30 and a top continuous steel reinforcement assembly 31. These two assemblies are arranged in layers along the thickness direction inside the precast waffle slab 4, located in the lower and upper regions of the slab respectively, together forming the spatial stress-bearing skeleton inside the slab. The ends of the steel bars in the top continuous steel reinforcement assembly 31 extend to the edge of the steel side formwork 2, providing an interface for the connection of steel bars between adjacent panels, ensuring the integrity of the steel reinforcement skeleton at the edge of the slab, and avoiding stress concentration caused by the end cut-off of the steel bars.

[0038] The top-layer continuous steel reinforcement assembly 31 of adjacent waffle bridge deck components is connected by a joint series sleeve 61. The joint series sleeve 61 is fitted between the protruding top-layer steel reinforcement ends of the two adjacent panels, and has an internal connecting structure to fix the steel reinforcement. This allows the top-layer steel reinforcement to form a continuous force transmission path across the panel joint, enabling the top-layer steel reinforcement to transmit the tensile force at the joint, limiting the cracking of the concrete above the joint, and allowing multiple precast panels to be spliced ​​together to form a continuous bridge deck system with overall load-bearing performance close to that of a cast-in-place structure.

[0039] Based on the above embodiments, in this embodiment, the steel beam assembly 5 includes a steel beam flange 50 and a comb-shaped PBL connector 51. The steel beam flange 50 is disposed between two adjacent waffle bridge deck assemblies, serving as the upper bearing surface of the beam structure and the deck support reference. The comb-shaped PBL connector 51 is welded to the steel beam flange 50 and is provided with inclined guide teeth. The inclined guide teeth have an inclination angle of 15° to 60° to form an inclined guide structure on the steel beam flange 50. The position of the inclined guide teeth matches the position of the joint connecting steel bars 60 and is evenly arranged at a set interval so that the steel bars can be embedded therein. The comb-shaped PBL connector 51 extends longitudinally along the steel beam flange 50, covering the joint area of ​​the adjacent waffle bridge panel assembly. It provides horizontal limit and vertical support reference for panel hoisting, ensuring the planar position accuracy of the panel after it is in place. The comb-shaped PBL connector 51 and the steel beam flange 50 form a rigid whole, jointly bearing the load transmitted by the panel, avoiding local stress concentration that could lead to flange deformation.

[0040] In this embodiment, each inclined guide comb tooth has the same inclination direction and an inclination angle of 15° to 60°. This inclination angle range is determined based on structural stress analysis and construction guidance requirements. Too small an inclination angle may result in an excessively long guide stroke, while too large an inclination angle will weaken the wedge-shaped interlocking effect. The inclined surface of the inclined guide comb tooth forms the guide path for the joint connection reinforcement 60. The comb teeth are determined according to the position of the joint connection reinforcement 60 and are evenly arranged at a set spacing, which is consistent with the arrangement spacing of the outer reinforcement sleeve 21 of the side formwork. The joint connection reinforcement 60 slides into the comb-type PBL connector 51 along the inclined surface of the inclined guide comb tooth, achieving a non-conflicting interlocking connection between the plate beam and the plate beam. No additional adjustment or binding is required. The outer wall of the reinforcement contacts the inclined surface of the inclined guide comb tooth, and the inclined surface force is used to guide the reinforcement into the predetermined slot, avoiding deformation or damage caused by rigid collision between the end of the reinforcement and the comb-type PBL connector 51. This ensures the smoothness and accuracy of the reinforcement insertion process, while ensuring that the reinforcement axis is parallel to the guide surface, reducing installation errors.

[0041] The inclined opening of the comb-type PBL connector 51 faces the waffle plate hoisting direction, allowing the joint connecting steel bar 60 to automatically slide into the gap between the comb teeth along the inclined surface during the plate's weight-bearing positioning process, eliminating the need for manual hole alignment. After the inclined opening of the comb-type PBL connector 51 is connected and positioned with the joint connecting steel bar 60, a wedge-shaped interlocking effect is formed. When the plate-beam interface is subjected to a lifting force, the inclined surface converts part of the upward pull force into a lateral restraint force, exhibiting superior resistance to lifting compared to vertically perforated PBL connectors. The presence of the inclined surface alters the normal direction of the contact surface, causing the tensile force perpendicular to the plate surface to be decomposed into a component along the inclined surface direction. This component is borne by the lateral stiffness of the inclined guide comb teeth, thereby reducing the bending moment at the root of the comb-type PBL connector 51. The inclined opening ensures that the long axis of the concrete tenon formed after pouring is aligned with the shear flow direction at the slab-beam interface. The concrete tenon is under a combined compressive and shear stress state, which helps to leverage the compressive strength of concrete, prevents premature brittle failure of the concrete tenon under pure shear action, improves the mechanical properties of the connection interface, and ensures the reliability of the slab-beam joint under complex stress conditions.

[0042] The joint connecting steel bars 60, which pass through the outer steel bar sleeve 21 of the side formwork, simultaneously bear the longitudinal force transmission function of the slab-to-slab connection and the interface shear force transmission function of the slab-beam connection. The joint series sleeve 61 controls the spacing of the joint steel bars to ≤200mm, improving the crack resistance of the joint, thereby enhancing the lateral restraint and shear bearing capacity of the concrete tenon of the comb-type PBL connector 51, forming a dual-system mechanical synergistic enhancement effect. The joint connecting steel bars 60 are anchored inside the precast waffle slab 4 through the outer steel bar sleeve 21 of the side formwork, and the other end is embedded in the gap of the comb-type PBL connector 51 and poured with concrete, forming a composite force transmission chain of steel bar-concrete-steel beam. The close arrangement with a spacing of ≤200mm ensures uniform lateral restraint of the concrete in the joint area, suppresses crack propagation, and guarantees the integrity of the concrete tenon. This allows shear force to be transferred to the inclined guide comb through the complete concrete tenon, avoiding uneven stress redistribution caused by concrete cracking. This ensures the overall stability and durability of the composite bridge structure under operational loads, achieves complementary mechanical properties between the slab-to-slab connection and the slab-to-beam connection, and gives the structural system continuous stiffness and strength at the joint.

[0043] In summary, the tandem sleeve plate connection and the inclined open comb-shaped plate beam connection in this application achieve structural coupling and mechanical synergy through the integrated sleeve system of the steel side formwork 2. The steel side formwork 2 is set around the perimeter of the precast waffle bridge deck. The inner steel reinforcement sleeve 20 and the outer steel reinforcement sleeve 21 are welded to the inner and outer sides of the steel side formwork 2, respectively, forming a steel reinforcement channel that runs through the wall of the steel side formwork 2. The inner steel reinforcement sleeve 20 passes through the full-length steel reinforcement assembly 3 of the slab, achieving precise positioning of the steel reinforcement during the precast stage. The outer steel reinforcement sleeve 21 is densely arranged at a spacing of less than or equal to 200 mm, specifically for passing through the joint connection assembly 6. Unlike the prior art scheme of independently setting extrusion sleeves at the end of the precast slab, the spacing of the outer sleeve of the steel side formwork 2 in this application is not constrained by the spacing of the waffle ribs and can be flexibly adjusted to meet the specification limits, compensating for insufficient bottom reinforcement caused by excessive waffle rib spacing. The outer sleeve of the steel side formwork 2 has three functions: it serves as a rebar positioning base during the prefabrication stage, as a rebar connection channel during the splicing stage, and as an integrated component with the steel side formwork 2 through welding during the anchoring stage. The steel side formwork 2, through the interlocking of the inner rebar sleeve 20 with the top and bottom continuous rebar components 31 and 30, forms an integral structure with the precast waffle slab 4. During demolding, the steel side formwork 2 and the precast waffle slab 4 detach from the bottom formwork structure simultaneously, making the steel side formwork 2 a permanent structural component of the waffle bridge deck assembly rather than a temporary template. The integrated steel side formwork 2 continues to participate in structural stress during subsequent use, providing lateral restraint and additional stiffness. Simultaneously, it serves as a positioning base for the joint connection component 6, avoiding the sleeve positioning offset problem after demolding in traditional processes, forming a functionally progressive reinforcement chain.

[0044] The tandem sleeve controls the spacing of the joint connecting reinforcement bars 60 to less than or equal to 200mm, providing dense lateral restraint to the concrete in the joint area, reducing crack width, and maintaining concrete integrity. This improved concrete integrity results in better lateral support for the concrete tenon at steel beam assembly 5, increasing its compressive strength and thus enhancing the shear capacity of the slab-beam connection. Conversely, steel beam assembly 5 provides reliable shear force transfer at the slab-beam interface, effectively transferring longitudinal shear force in the joint area to the steel beam flange 50, resulting in a more uniform shear force distribution and reduced risk of joint cracking. The two systems create a positive mechanical feedback loop: the compliant joint reinforcement spacing controlled by the tandem sleeve improves the joint's crack resistance, and the improved concrete integrity in the joint area provides better lateral restraint to the concrete tenon of the comb-type PBL connector 51. The effectiveness of the two systems is mutually reinforcing rather than simply additive. The joint connection component 6 is inserted into the outer steel reinforcement sleeve 21 of the side formwork of the adjacent waffle bridge panel component and is set in the steel beam component 5, so that one end of the joint connection component 6 is fixed to the edge of the steel side formwork 2 of the panel and the other end extends to the guide surface area of ​​the steel beam component 5, thus establishing a physical connection path between panels and between the panel and the beam.

[0045] The slabs are connected by joint tandem sleeves 61, and the slabs and beams are connected by inclined open comb-tooth PBL connectors 51. The two are structurally coordinated through an integrated sleeve system of steel side formwork 2. The joint connecting steel bars 60, which are inserted through the outer sleeve of the steel side formwork 2, have their protruding ends serving as both the connection end of the joint tandem sleeves 61 and the sliding end of the comb-tooth PBL connectors 51. The same batch of steel bars transmits longitudinal tensile and compressive forces at the slab-slab interface through the joint tandem sleeves 61, and transmits interfacial shear forces at the slab-beam interface through the comb-tooth PBL connectors 51, achieving a "dual-purpose" structural integration. This integrated reinforcement-connection approach eliminates the spatial conflict between the joint steel bars and the shear-force comb-tooth PBL connectors 51 in traditional schemes. In traditional schemes, slab-slab connections and slab-beam connections need to be implemented step-by-step; in this scheme, the butt joint of the slab-slab tandem sleeves and the sliding engagement of the comb-tooth connectors in the slab-beam are completed in the same hoisting process, eliminating the need for secondary adjustments. The joint connecting reinforcement 60 includes the bottom joint longitudinal reinforcement 600 and the bottom joint transverse reinforcement 601. The bottom joint transverse reinforcement 601 is installed through the side formwork outer reinforcement sleeve 21 with a spacing of less than or equal to 200mm to compensate for the insufficient bottom reinforcement caused by the waffle plate rib spacing being greater than 600mm. The layout position and spacing of the side formwork outer reinforcement sleeve 21 are determined according to the position and spacing of the joint connecting reinforcement 60 supplemented at the joint, so as to realize continuous force transmission between the slabs.

[0046] The steel beam assembly 5 includes a steel beam flange 50 and a comb-type PBL connector 51. The comb-type PBL connector 51 includes multiple inclined guide teeth spaced apart along the length of the steel beam flange 50. The inclined guide teeth are inclined at an angle of 15° to 60° to form an inclined guide structure on the steel beam flange 50. Traditional comb-type PBL connectors 51 use vertical openings, requiring reinforcing bars to be inserted into the holes from above. This causes serious interference with the dense reinforcing bars between the ribs of the waffle plate during construction. This application changes the opening to an inclined opening comb-tooth structure, with the inclined opening facing the direction of the waffle plate hoisting and positioning. This allows the joint connecting reinforcing bars 60 to automatically slide into the gaps between the comb teeth along the inclined surface during the positioning process under the weight of the plate, eliminating the need for manual hole alignment. The inclined opening allows the joint connecting reinforcing bars 60 to slide into position from the side along the inclined surface, eliminating the need for top-level drilling and completely avoiding interference with the inter-rib reinforcing bars. The connection action is changed from "penetration" to "sliding," cleverly utilizing the wall panel and its own weight to achieve automatic alignment and locking of the connecting reinforcing bars. The inclined surface creates a wedge-shaped interlocking effect after the reinforcement is in place. When the slab-beam interface is subjected to a lifting force, the inclined surface converts part of the upward force into a lateral restraint force, which is superior to the vertically perforated comb-type PBL connector 51 in terms of resistance to lifting. The inclined opening makes the long axis of the concrete tenon formed after pouring consistent with the shear force flow direction of the slab-beam interface. The concrete tenon is in a state of combined compression and shear stress rather than a pure shear state, which is conducive to giving full play to the compressive strength of concrete. The sliding installation makes the reinforcement and the comb teeth fit tightly, enhances the wedge-shaped interlocking effect, improves the stress state of the concrete tenon, and forms a positive feedback chain.

[0047] Secondly, embodiments of this application provide a construction method for a dual-system connection structure of precast waffle slabs for composite beams, used to construct the dual-system connection structure of precast waffle slabs for composite beams provided in any of the above embodiments of this application, comprising: A steel support frame, a steel bottom mold panel 10, and an array-type rib forming mold box 11 are laid on the bottom mold platform, and a release agent is applied to the mold box 11 to complete the installation of the bottom mold structure 1. The mold box 11 is a frustum shape with the small end facing upward. A steel side mold 2 is installed on the bottom mold structure 1 to form a closed casting cavity, and an inner steel bar sleeve 20 and an outer steel bar sleeve 21 are installed on the steel side mold 2. The continuous steel reinforcement assembly 3 of the slab is inserted through the steel reinforcement sleeve 20 inside the side formwork; By passing the joint connecting steel bar 60 through the outer steel bar sleeve 21 of the side formwork, a closely spaced joint reinforcement is formed; Concrete is poured into a closed casting cavity and steam-cured to form an integrated precast steel-concrete waffle bridge deck assembly with steel side molds 2. The integrated precast steel-concrete bridge deck assembly is hoisted onto the steel beam assembly 5. Adjacent waffle slabs are connected to the butt joint of the steel reinforcement 60 via a series joint sleeve 61. The joint connecting steel bar 60 slides into the inclined guide structure of the comb-shaped PBL connector 51 to complete the plate-beam connection.

[0048] Specifically, the construction of the composite bridge structure includes the following steps: installation of the bottom formwork structure, arrangement of steel side formwork 2 and sleeves, reinforcement installation, concrete pouring, demolding and hoisting, and connection construction. The installation of the bottom formwork structure involves laying a steel support frame and a steel bottom formwork panel 10 on the bottom formwork platform, and arranging array-type ribbed forming mold boxes 11 on the steel bottom formwork panel 10. The mold boxes 11 are frustum-shaped with the small end facing upwards and are coated with a release agent to form the forming space for the waffle ribs, providing bottom support and shape constraint for the precast waffle slabs 4. The frustum-shaped design facilitates demolding after the concrete has cured, reducing the adhesion between the mold box 11 and the concrete.

[0049] A steel side mold 2 is installed on the bottom mold structure to form a closed pouring cavity. The steel side mold 2 is made of steel and surrounds the bottom mold structure. Positioning holes are opened according to the positions of the continuous steel reinforcement components 3 of the plate. The inner steel reinforcement sleeve 20 and the outer steel reinforcement sleeve 21 of the side mold are welded to each other. The inner steel reinforcement sleeve 20 is welded to the positioning hole on the inside of the steel side mold 2, and the outer steel reinforcement sleeve 21 is welded to the outside of the steel side mold 2. The weld joints of the inner steel reinforcement sleeve 20, the outer steel reinforcement sleeve 21 and the steel side mold 2 adopt a double-sided welding process. The welding thickness is not less than the minimum value of the sleeve wall thickness and the steel side mold 2 thickness to ensure the load-bearing capacity and structural stability of the sleeve connection, avoid stress concentration at the joint leading to damage, enable the sleeve to withstand the lateral pressure during concrete pouring and the subsequent structural stress, and ensure the long-term reliability of the steel reinforcement positioning.

[0050] During the reinforcement installation stage, the continuous reinforcement assembly 3 of the slab is inserted through the inner reinforcement sleeve 20 of the side formwork. The bottom continuous reinforcement of the longitudinal and transverse ribs and the top continuous longitudinal and transverse reinforcement of the top slab are inserted through the inner sleeve and positioning holes of the steel side formwork 2. The inner reinforcement sleeve 20 of the side formwork provides precise positioning for the reinforcement, ensuring the spatial accuracy of the reinforcement cage within the pouring cavity and preventing displacement of the reinforcement during concrete vibration. Simultaneously, the longitudinal and transverse joint connecting reinforcement 60 is inserted through the outer reinforcement sleeve 21 of the side formwork, forming a closely spaced joint reinforcement. The center-to-center spacing of the outer reinforcement sleeve 21 of the side formwork is determined based on the waffle slab rib spacing. When the rib spacing is 60-100cm, no fewer than 3 outer reinforcement sleeves 21 are placed between every two adjacent ribs, controlling the spacing of the bottom joint transverse reinforcement 601 within the range of 150-200mm. This compensates for insufficient bottom reinforcement caused by excessive waffle slab rib spacing and meets the reinforcement limit requirements of the specifications.

[0051] Subsequently, concrete or high-strength concrete is poured into the closed casting cavity and steam-cured to form an integrated steel-concrete composite waffle slab with steel side molds 2. The integrated steel-concrete precast waffle bridge deck assembly is formed by pouring concrete together with steel side molds 2, inner steel sleeves 20, outer steel sleeves 21, continuous steel reinforcement assemblies 3, joint connecting steel reinforcement 60, and steel. The concrete forms an integral whole with the steel side molds 2 through the embedding and interlocking of the inner steel sleeves 20. During demolding, the steel side molds 2 and the precast waffle slab 4 are removed from the bottom mold structure 1 together. The steel side molds 2 become a permanent structural component of the precast waffle bridge deck assembly rather than a temporary formwork. In the subsequent use stage, they continue to participate in the structural stress, providing lateral restraint and additional stiffness. At the same time, they serve as the positioning base for the joint connecting steel reinforcement 60, avoiding the problem of sleeve positioning displacement after demolding in traditional processes.

[0052] After demolding, the bottom formwork structure is removed, and the waffle bridge panel assembly is hoisted above the steel beam assembly 5. The steel beam assembly 5 is pre-installed on the main steel beam or crossbeam and has an inclined guide structure. Adjacent waffle bridge panel assemblies are connected by joint connector 6, specifically, adjacent waffle plates are connected by joint sleeves 61 to connect the reinforcing bars, achieving continuous force transmission between the plates. At the same time, the joint connecting reinforcing bars 60 are slid into the steel beam assembly 5 along the comb-shaped PBL inclined surface, completing the rapid connection of the plate and beam. The joint connecting reinforcing bars 60 and the plate's continuous reinforcing bar assembly 3 together form a continuous load-bearing reinforcing mesh, improving the integrity and crack resistance of the wet joint. The joint connecting reinforcing bars 60 automatically slide into the gap of the comb teeth along the inclined surface, eliminating the need for manual hole alignment. The automatic alignment and locking of the connecting reinforcing bars is achieved through the gravity positioning process of the plate. The inclined surface converts part of the upward pull force into the lateral restraint force, resulting in better anti-lifting ability than the vertically perforated comb-shaped PBL connector 51. Finally, concrete is poured at the joint of adjacent waffle bridge panel assemblies to complete the construction of the composite bridge structure. This construction method integrates the plate-to-plate connection and the plate-to-beam connection into the same hoisting process, eliminating the need for separate steps. It enables rapid assembly of the entire cross-section of the waffle plate and the steel-concrete composite beam, ensuring the geometric accuracy and fit of the connection interface and improving the durability and safety of the structure during operation.

[0053] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0054] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0055] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A dual-system connection structure for precast waffle slabs in composite beams, characterized in that, It includes: The prefabricated waffle bridge deck assembly includes a prefabricated waffle slab (4), a steel side mold (2) surrounding the prefabricated waffle slab (4), and a continuous steel reinforcement assembly (3) for the slab. The steel side mold (2) forms a closed casting cavity. The inner wall of the side mold is welded with a steel reinforcement sleeve (20) that penetrates the wall surface, and the outer wall is welded with a steel reinforcement sleeve (21). The continuous steel reinforcement assembly (3) for the slab passes through the steel reinforcement sleeve (20) of the side mold. The horizontal spacing between two adjacent steel reinforcement sleeves (21) of the side mold is less than or equal to 200 mm. The joint connection assembly (6) includes a joint connection steel bar (60) and a joint tandem sleeve (61), wherein the joint connection steel bar (60) is inserted inside the side formwork outer steel bar sleeve (21); The steel beam assembly (5) includes a steel beam flange (50) and a comb-shaped PBL connector (51) disposed on the steel beam flange (50), the comb-shaped PBL connector (51) having an inclined guide structure; Among them, the joint connecting steel bars (60) between two adjacent prefabricated waffle bridge panel components are inserted into the corresponding side formwork outer steel bar sleeves (21) and connected by the joint series sleeves (61) to form a plate-to-plate connection system. The joint connecting steel bars (60) are inserted into the inclined guide structure of the comb-type PBL connector (51) to form a plate-beam connection system; The joint connecting steel bar (60) simultaneously connects the adjacent precast waffle bridge panel assembly and the comb-type PBL connector (51), forming a shared force transmission component for the slab-slab connection system and the slab-beam connection system, thus forming a slab-slab-beam dual-system collaborative force transmission path.

2. The dual-system connection structure for precast waffle slabs in composite beams as described in claim 1, characterized in that: The inner steel reinforcement sleeve (20) of the side formwork includes a top inner sleeve and a bottom inner sleeve, wherein the top inner sleeve is located at the top of the bottom inner sleeve; The top inner sleeves on the opposite side walls of the steel side mold (2) are correspondingly provided, and the bottom inner sleeves on the opposite side walls of the steel side mold (2) are correspondingly provided. The steel side formwork (2) is provided with a rebar positioning hole corresponding to the position of the continuous rebar assembly (3) of the plate. The rebar sleeve (20) inside the side formwork is welded to the rebar positioning hole. The continuous rebar assembly (3) of the plate passes through the rebar positioning hole and the rebar sleeve (20) inside the side formwork.

3. The dual-system connection structure for precast waffle slabs in composite beams as described in claim 2, characterized in that, The continuous steel reinforcement assembly (3) of the plate body includes: The bottom continuous steel reinforcement assembly (30) includes a transverse bottom steel reinforcement (300) and a longitudinal bottom steel reinforcement (301), both ends of which are inserted into the corresponding bottom inner sleeve. The top-level continuous steel reinforcement assembly (31) includes top-level longitudinal steel reinforcement (310) and top-level transverse steel reinforcement (311), both of which are inserted into the corresponding top-level inner sleeve.

4. The dual-system connection structure for precast waffle slabs in composite beams as described in claim 1, characterized in that: The joint connecting reinforcement (60) includes bottom joint longitudinal reinforcement (600) and bottom joint transverse reinforcement (601). The bottom joint transverse reinforcement (601) is provided with a side formwork outer reinforcement sleeve (21). The horizontal spacing between two adjacent bottom joint transverse reinforcements (601) is less than or equal to 200mm.

5. The dual-system connection structure for precast waffle slabs in composite beams as described in claim 1, characterized in that: One end of the joint connecting steel bar (60) is connected to the outer steel bar sleeve (21) of the side formwork, and the other end is connected to the joint connecting steel bar (60) of the adjacent precast waffle bridge panel assembly through the joint series sleeve (61) to form a continuous force transmission structure between the panels.

6. The dual-system connection structure for precast waffle slabs in composite beams as described in claim 1, characterized in that: The inner wall of the side mold is welded to the inner wall of the steel side mold (2), and one end of the inner wall of the side mold is extended into the precast waffle slab (4). The slab-body through-length steel reinforcement assembly (3) passes through the inner wall of the side mold and is anchored in the precast waffle slab (4).

7. The dual-system connection structure for precast waffle slabs in composite beams as described in claim 1, characterized in that: The comb-type PBL connector (51) is welded to the steel beam flange (50) and is provided with inclined guide comb teeth. The inclined guide comb teeth have an inclination angle of 15°~60° to form an inclined guide structure on the steel beam flange (50). The inclined guide comb teeth are positioned to match the position of the joint connecting steel bars (60) and are evenly arranged at a set interval; The joint connecting steel bar (60) slides into the comb-type PBL connector (51) along the inclined surface of the inclined guide comb.

8. The dual-system connection structure for precast waffle slabs in composite beams as described in claim 1, characterized in that: The inclined opening direction of the comb-type PBL connector (51) faces the hoisting and positioning direction of the prefabricated waffle bridge panel assembly. The inclined opening of the comb-type PBL connector (51) is connected to the joint connecting steel bar (60) to form a wedge-shaped interlocking structure.

9. A construction method for a double-system connection structure for precast waffle slabs of composite beams, used to construct a double-system connection structure for precast waffle slabs of composite beams as described in any one of claims 1 to 8, characterized in that, It includes: A steel support frame, a steel bottom mold panel (10), and an array-type rib forming mold box (11) are laid on the bottom mold platform, and a release agent is applied to the mold box (11) to complete the installation of the bottom mold structure (1). The mold box (11) is a frustum shape with the small end facing upward. A steel side mold (2) is installed on the bottom mold structure (1) to form a closed casting cavity, and an inner steel bar sleeve (20) and an outer steel bar sleeve (21) are installed on the steel side mold (2). The slab-length steel reinforcement assembly (3) is inserted through the steel reinforcement sleeve (20) inside the side formwork. By passing the joint connecting steel bars (60) through the outer steel bar sleeve (21) of the side formwork, a closely spaced joint reinforcement is formed; Concrete is poured into a closed casting cavity and steam-cured to form an integrated precast steel-concrete waffle bridge deck assembly with steel side molds (2). The integrated steel-concrete precast waffle bridge panel assembly is hoisted onto the steel beam assembly (5); Adjacent waffle slabs are connected to the joint reinforcement (60) by a series sleeve (61) at the joint; The joint connecting steel bar (60) slides into the inclined guide structure of the comb-type PBL connector (51) to complete the plate beam connection.

10. The construction method for the dual-system connection structure of precast waffle slabs for composite beams as described in claim 9, characterized in that: The integrated steel-concrete precast waffle bridge deck assembly is formed by casting concrete together with steel side mold (2), inner steel sleeve (20) of side mold, outer steel sleeve (21) of side mold, continuous steel reinforcement assembly (3) of the slab body, joint connecting steel reinforcement (60). The concrete forms an integral whole with the steel side mold (2) through the embedding and interlocking of the inner steel sleeve (20) of side mold. When demolding, the steel side mold (2) and the precast waffle slab (4) are separated from the bottom mold structure (1). The joint connecting steel bars (60) and the plate through steel bar assembly (3) form a continuous stress-bearing steel mesh structure; The center spacing of the side formwork outer steel sleeves (21) is determined according to the waffle plate rib spacing. When the rib spacing is 60~100cm, no less than 3 side formwork outer steel sleeves (21) are arranged between every two adjacent ribs, so that the spacing of the bottom joint transverse steel bars (601) is set in the range of 150~200mm. The welded joints of the inner steel bar sleeve (20) and outer steel bar sleeve (21) of the side formwork with the steel side formwork (2) adopt a double-sided welding process, and the welding thickness is greater than or equal to the minimum value between the sleeve wall thickness and the steel side formwork (2).

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