Composite slabs and prefabricated composite ribs for composite slabs

Abstract

This application provides a composite slab and prefabricated composite ribs for composite slabs, belonging to the field of prefabricated buildings. The composite slab includes a prefabricated base slab and prefabricated composite ribs. The prefabricated composite ribs include at least a frame, a first concrete rib segment, and a second concrete rib segment. The bottom of the frame is embedded and fixed to the prefabricated base slab. The first and second concrete rib segments are formed around the upper chord of the frame, forming a space between the first concrete rib segment and the prefabricated base slab. The bottom of the second concrete rib segment forms a continuous force transmission structure with the prefabricated base slab. The continuous force transmission structure is located in the load concentration area of ​​the composite slab. By using composite ribs, variable stiffness ribs are achieved with the first and second concrete rib segments. In the load concentration area (the area with the largest bending moment), the second concrete rib segment directly transmits force with the prefabricated base slab to meet greater stiffness requirements. In the non-load concentration area, the first concrete rib segment is used to save materials, making the overall stiffness of the composite slab about 1.5 times higher than that of traditional concrete rib composite slabs.

Description

Technical Field

[0001] This invention belongs to the field of prefabricated buildings, and in particular relates to a composite slab and a prefabricated composite rib for the composite slab. Background Technology

[0002] As an important component in the field of prefabricated buildings, reinforced concrete composite slabs mainly consist of reinforced concrete ribs and precast base slabs. The reinforced concrete ribs enhance the rigidity of the precast base slabs, making them easier to transport and hoist and preventing cracking. Therefore, reinforced concrete composite slabs have been widely promoted and applied in floor slabs and floor structures due to their advantages such as good vertical rigidity, convenient construction, and cost savings.

[0003] However, during hoisting, transportation, and installation, the bending moment of the composite slab is greatest in the middle and least at the sides; the load is concentrated in the central region of the slab. Traditional composite slabs, whether with truss ribs or concrete ribs, have high stiffness requirements in the central region, which are difficult to meet during hoisting, transportation, and installation, leading to problems such as concrete rib cracking and truss rib deformation.

[0004] Furthermore, when laying pipelines in concrete rib composite slabs, slots are often cut into the ribs, which further compromises the structural strength. Meanwhile, truss rib composite slabs are difficult to meet stiffness requirements over large spans.

[0005] Therefore, this invention came into being.

[0006] It should be noted that the information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] One objective of this invention is to provide a composite plate with variable stiffness that can meet the requirements of uneven load distribution.

[0008] The second objective of this invention is to propose a prefabricated composite rib for composite slabs that can achieve variable stiffness, and to apply it in the structure of composite slabs.

[0009] To achieve at least one of the above objectives, the present invention first provides a composite plate, comprising:

[0010] Precast base slab;

[0011] The precast composite rib includes at least a frame, a first concrete rib segment, and a second concrete rib segment. The bottom of the frame is embedded and fixed to the precast base plate. The first concrete rib segment is formed around the upper chord of the frame, forming a space between the first concrete rib segment and the precast base plate. The second concrete rib segment is formed around the upper chord of the frame, and the bottom of the second concrete rib segment forms a continuous force transmission structure with the precast base plate. The continuous force transmission structure is located in the load concentration area of ​​the composite slab.

[0012] Preferably, the continuous force transmission structure is implemented such that the second concrete rib segment is integrally cast with the precast base plate; or, the second concrete rib segment is in force transmission contact or connection with the precast base plate.

[0013] Preferably, the prefabricated composite rib further includes a lower chord, which is connected to the web members of the frame and forms a truss with the web members and the upper chord. The lower chord is embedded and fixed to the prefabricated base plate.

[0014] Preferably, a support rib is provided between the end of the lower chord and the end of the upper chord.

[0015] Preferably, the location of the first concrete rib corresponds to the load-dispersed area of ​​the composite slab.

[0016] Preferably, the load concentration area is defined as the area with a large mid-span bending moment of the composite slab; the load non-concentration area is defined as the area with a small side-span bending moment of the composite slab.

[0017] Preferably, the number of the first concrete rib segments is at least two, with one second concrete rib segment located between the two first concrete rib segments.

[0018] Preferably, a steel rib segment is formed between the first concrete rib segment of the precast composite rib and the edge of the precast base plate, and the steel rib segment is implemented as a pipeline routing section.

[0019] The technical effects of the above-mentioned technical solutions of the present invention arise from one or more of the following combinations:

[0020] By using a combination of ribs, a variable stiffness rib is achieved by using a first concrete rib segment and a second concrete rib segment. In the load concentration area (the area with the largest bending moment), the second concrete rib segment directly transmits force with the precast base plate to meet the greater stiffness requirements. In the load non-concentration area, the first concrete rib segment is used to save materials, so that the stiffness of the overall composite slab is increased by about 1.5 times compared with the traditional concrete rib composite slab.

[0021] The overall structure offers a wider range of choices for precast base slabs, including prestressed base slabs, high-performance concrete base slabs, and ordinary concrete base slabs. When using prestressed base slabs, the second concrete rib segment in the load concentration area (the area with the largest bending moment) is cast integrally with the precast base slab or in contact with it for force transmission. This can also prevent the precast base slab from arching and can further reduce the thickness of the precast base slab.

[0022] The steel structure in the precast composite rib can be either a frame or a truss. When using a frame, the web members are fixed to the structural reinforcement of the precast base plate. When using a truss, the lower chord is fixed to the structural reinforcement of the precast base plate, which is simple and convenient.

[0023] In this scheme, the variable stiffness precast composite ribs, the second concrete rib segment in the 30% area of ​​the mid-span (where the bending moment is large) can be precast in the factory or integrally formed with the composite base plate; in the 30% area on both sides of the span (where the bending moment is small), the first concrete rib segment is precast in advance using UHPC ribs, which together with the truss reinforcement form the precast ribs to achieve industrialized production; in the 10% area at the ends, the steel rib segment is directly made of truss reinforcement, which facilitates the passage of larger diameter pipelines.

[0024] The truss reinforcement uses 6, 5, and 5 diameter steel bars (mm); the top chord reinforcement uses 6; the web members and bottom chord use 5. The ends are welded with support bars to increase the stiffness contribution of the ribs, realize the continuity of the slab, and transform the simply supported slab into a continuous slab.

[0025] In the mid-span section (where the bending moment is large), a precast steel mesh is used to form the space for the second concrete rib segment. The ribs are then directly fitted onto the precast composite ribs in the factory to improve on-site construction efficiency.

[0026] The present invention also provides a prefabricated composite rib for a composite slab, comprising at least a frame, two first concrete rib segments and a second concrete rib segment; the first concrete rib segment is formed over the upper chord of the frame, the second concrete rib segment is formed over the upper chord of the frame and located between the two first concrete rib segments, and the bottom of the second concrete rib segment has a force-transmitting contact surface with the prefabricated bottom plate of the composite slab, the position of the force-transmitting contact surface corresponding to the load concentration area of ​​the composite slab.

[0027] The technical effects of the above-mentioned technical solution of the present invention are as follows:

[0028] The precast composite ribs of the present invention can be prefabricated in a factory in large quantities. The first concrete rib segment and the second concrete rib segment are precast and formed, and then transported in batches to the composite slab factory for composite slab forming. The process is simple and does not require secondary formwork for the first concrete rib segment and the second concrete rib segment.

[0029] The present invention also provides a prefabricated composite rib for a composite slab, comprising at least a frame and two first concrete rib segments; the first concrete rib segments are formed over the upper chord of the frame, and a second concrete rib segment forming space is formed between the two first concrete rib segments. The second concrete rib segment forming space is integrally formed with the prefabricated base plate of the composite slab to form the second concrete rib segment. The second concrete rib segment and the prefabricated base plate form a continuous force transmission structure, and the continuous force transmission structure is located in the load concentration area of ​​the composite slab.

[0030] The technical effects of the above-mentioned technical solution of the present invention are as follows:

[0031] The precast composite ribs of the present invention can be precast in a factory in large quantities. The first concrete rib segment is precast to reserve space for the formation of the second concrete rib segment. The ribs are transported in batches to the composite slab factory for the formation of the composite slab. The second concrete rib segment and the precast base slab are cast together, resulting in better integrity and stronger load-bearing capacity. Attached Figure Description

[0032] Figure 1 This is a schematic diagram illustrating a composite slab structure.

[0033] Figure 2 This diagram illustrates another structural design of the composite slab.

[0034] Figure 3 This is a front view of a composite slab structure.

[0035] Figure 4 This shows another structural front view of the composite slab.

[0036] Figure 5 This is a front view of the prefabricated composite ribs after they have been formed.

[0037] Figure 6 This diagram illustrates the structure of the prefabricated composite ribs after molding.

[0038] Figure 7 This diagram illustrates the location of the forming space for the second concrete rib segment in a precast composite rib.

[0039] Figure 8 This is a front view of the formwork support for the cast-in-place mesh plate in the precast composite rib.

[0040] Figure 9 This is a three-dimensional diagram showing the formwork support for the cast-in-place mesh plate in the precast composite rib.

[0041] Figure 10 This diagram illustrates the forming process of the second concrete rib segment in a precast composite rib.

[0042] The components are: 1. Precast base slab; 2. Precast composite ribs; 21. Truss; 211. Top chord; 212. Web members; 213. Bottom chord; 214. Support reinforcement; 22. First concrete rib segment; 23. Second concrete rib segment; 230. Forming space of the second concrete rib segment; 231. Cast-in-place mesh plate; 2311. Side plate; 2312. End plate; 2313. Base slab; 24. Steel rib segment. Detailed Implementation

[0043] The following description is provided to enable those skilled in the art to implement and use the invention and adapt it to specific application contexts. Various modifications and uses in different applications will be readily apparent to those skilled in the art, and the general principles defined herein are applicable to a wide range of embodiments. Therefore, the invention is not limited to the embodiments given herein, but should be granted the broadest scope consistent with the principles and novel features disclosed herein.

[0044] In the following detailed description, numerous specific details are set forth to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that practice of the invention is not necessarily limited to these specific details. In other words, well-known structures and devices are shown in block diagram form without being depicted in detail to avoid obscuring the invention.

[0045] Readers should note all documents and references submitted concurrently with this specification and open to public inspection, the contents of which are incorporated herein by reference. Unless otherwise expressly stated, all features disclosed in this specification (including any appended claims, abstracts, and drawings) may be replaced by alternative features for the same, equivalent, or similar purposes. Therefore, unless explicitly stated otherwise, each disclosed feature is merely one example of a set of equivalent or similar features.

[0046] Note that, where used, the markings left, right, front, back, top, bottom, front, back, clockwise, and counterclockwise are merely for convenience and do not imply any specific fixed direction. In fact, they are used to reflect the relative position and / or orientation between different parts of an object. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0048] Note that, in practice, "further," "preferably," "even further," and "more preferably" are simply starting points for describing another embodiment based on the foregoing embodiments. The combination of the content following "further," "preferably," "even further," or "more preferably" with the foregoing embodiments constitutes the complete configuration of another embodiment. Any combination of several "further," "preferably," "even further," or "more preferably" settings following the same embodiment can form yet another embodiment.

[0049] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the aspects described below with reference to the accompanying drawings and specific embodiments are merely exemplary and should not be construed as limiting the scope of protection of the present invention in any way.

[0050] Application Overview:

[0051] Composite slabs comprise a precast base slab and a composite layer (cast-in-place layer). The most widely marketed composite slabs are reinforced steel truss composite slabs and concrete-ribbed composite slabs. As those skilled in the art will understand, for ease of description, the factory-prefabricated components—precast base slab + reinforced steel truss; or precast base slab + concrete ribs—are generally referred to as composite slabs, as the core of this technical field generally lies in the technological advancements of the precast components. Therefore, this application also refers to the precast base slab and precast composite ribs as composite slabs, without describing the composite cast-in-place layer, which should be clear to those skilled in the art.

[0052] Structural Example 1:

[0053] Please combine Figures 1-10 This embodiment provides a composite slab, including a precast base slab 1 and precast composite ribs 2. The precast composite ribs 2 include at least a frame, a first concrete rib segment 22, and a second concrete rib segment 23. The bottom of the frame is embedded and fixed to the precast base slab 1. The first concrete rib segment 22 is formed around the upper chord 211 of the frame, forming a space between the first concrete rib segment 22 and the precast base slab 1. The second concrete rib segment 23 is formed around the upper chord 211 of the frame, and the bottom of the second concrete rib segment 23 forms a continuous force transmission structure with the precast base slab 1. This continuous force transmission structure is located in the load concentration area of ​​the composite slab.

[0054] This embodiment does not impose a unique restriction on the type of precast base plate 1; high-performance concrete slabs, prestressed concrete slabs, etc., can be selected.

[0055] As is well known, the bending moment is largest in the mid-span region of a composite slab, while it is smaller in the two side regions. Therefore, the stiffness requirement is greatest at the mid-span and gradually decreases towards the two side edges. Thus, in this embodiment, the load-concentrated region is defined as the mid-span region of the composite slab with a large bending moment; the load-dispersed region is defined as the region of the composite slab with a smaller bending moment at the side edges. Specifically, during hoisting and installation, the load is larger in the 30% mid-span region (with a larger bending moment), and a high-stiffness structural rib is used to strengthen it through the continuous structure of the second concrete rib segment 23 and the precast base slab 1; the load is smaller in the 30% side span regions (with a smaller bending moment), and the first concrete rib segment 22 is precast in advance using UHPC ribs, which together with the truss 21 steel reinforcement form precast ribs to achieve industrialized production.

[0056] The continuous force transmission structure between the second concrete rib segment 23 and the precast base slab 1 is implemented either through surface-to-surface contact or by being cast integrally as a whole. That is, the continuous force transmission structure is implemented by casting the second concrete rib segment 23 and the precast base slab 1 integrally. Figure 1 Alternatively, the second concrete rib segment 23 may be in contact with or connected to the precast base slab 1 for force transmission. Figure 2 ).

[0057] When the second concrete rib segment 23 is integrally cast with the precast base slab 1, please combine with... Figure 1 , Figure 3 , Figure 7 and Figure 8 and Figure 9 Preferably, the first concrete rib segment 22 is pre-cast at 30% of the span on both sides (where the bending moment is smaller), forming a second concrete rib segment forming space 230 between the two first concrete rib segments 22. Further, a casting mesh plate 231 is provided at the bottom and sides of the second concrete rib segment forming space 230, and the second concrete rib segment forming space 230 is enclosed by the casting mesh plate 231.

[0058] For details, please refer to Figure 9 The cast-in-place mesh plate 231 includes at least a bottom plate 2313 and side plates 2311, with the two side plates 2311 located on both sides of the upper chord 211. A space exists between the first concrete rib segment 22 and the top surface of the precast bottom plate 1. In a preferred embodiment, an end plate 2312 is provided to seal this space. Therefore, the side plates 2311 on both sides, the bottom plate 2313, and the end plates 2312 together form the casting space for the second concrete rib segment 23. During the casting process, the bottom plate 2313, side plates 2311, and end plates 2312 are all steel mesh plates. Their advantage lies in conveniently avoiding the position of the web members; where there is a conflict, the web members can be directly passed through the steel mesh plate, and positioning and fixing can also be achieved.

[0059] Furthermore, a steel rib segment 24 is formed between the first concrete rib segment 22 of the precast composite rib 2 and the edge of the precast base slab 1. The steel rib segment 24 is implemented as a pipeline routing section. Preferably, in a total area of ​​10% at both ends of the composite slab, the steel rib segment 24 is directly formed by the reinforcing steel of the truss 21, which facilitates the passage of larger diameter pipelines. It should be noted that the total area of ​​10% at both ends of the composite slab is not the only limitation; firstly, it does not limit the area parameters, and secondly, it does not limit its necessity. When the space below the first concrete rib segment 22 of the precast composite rib 2 can accommodate the routing, the steel rib segment 24 can be extended and replaced by the first concrete rib segment 22, forming a structure in which the first concrete rib segment 22 and the second concrete rib segment 23 are of equal length to the span of the precast base slab 1.

[0060] Furthermore, the end of the first concrete rib segment 22 facing the second concrete rib segment 23 can be configured as a vertical surface or a sloping surface; the end of the second concrete rib segment 23 can be configured as... Figure 3 The slope shown, or implemented as Figure 4 The vertical surface plus the sloping surface shown prevents stress concentration by varying the slope.

[0061] As described above, the entire precast composite rib 2 is implemented as a variable stiffness composite rib consisting of 5% steel rib segment 24 + 30% first concrete rib segment 22 + 30% second concrete rib segment 23 + 30% first concrete rib segment 22 + 5% steel rib segment 24, meeting the bending moment resistance requirements of different areas of the composite slab. It should be noted that this is a preferred embodiment and is not the only one. The proportions of each area can be reasonably varied according to actual needs or span design.

[0062] When the second concrete rib segment 23 comes into contact with the precast base slab 1, as follows: Figure 2 and Figure 4 As shown, the second concrete rib segment 23 and the first concrete rib segment 22 are pre-cast and then cast together with the precast base slab 1. The second concrete rib segment 23 is in contact with or connected to the precast base slab 1; this connection is implemented by pressing the second concrete rib segment 23 into the precast base slab 1 by 5-10mm, achieving partial interlocking with the precast base slab 1, and a burr surface can be formed on the pressed outer surface of the second concrete rib segment 23. Furthermore, when the second concrete rib segment 23 and the first concrete rib segment 22 are pre-cast, temporary formwork can be used to form the second concrete rib segment 23, or a non-removable steel mesh formwork can be used and fixed to the truss.

[0063] It is worth mentioning that, in this embodiment, the steel structure of the prefabricated composite rib 2 includes at least a frame consisting of an upper chord 211 and web members 212; in another aspect, the steel structure of the prefabricated composite rib 2 may also include a lower chord 213, thereby forming a truss 21 structure with the frame (upper chord 211 and web members 212). The two ends of the upper chord 211 may extend to the outer edge of the prefabricated base slab 1 to form an overlapping section, which may be welded to the composite layer structural reinforcement of the composite beam, or welded to the upper chord overlapping section of the adjacent composite slab to form a common load-bearing structure.

[0064] In one embodiment of this invention, the upper chord 211, lower chord 213, and web members 212 can be strip structures such as reinforcing bars, steel pipes, and structural steel. Furthermore, in this embodiment, the preferred steel structure is a truss 21, with reinforcing bars of diameters of 8, 6, and 4.5 mm. The upper chord 211 uses reinforcing bars of diameter 8 mm, with support bars 214 welded to the ends to increase the stiffness contribution of the ribs, achieving plate continuity and transforming a simply supported plate into a continuous plate.

[0065] As one implementation of this embodiment, the truss 21 or the web members 212 of the frame can be single-row web members, double-row web members, or triangular web members, etc.

[0066] As one implementation method of this embodiment, please refer to Figure 10 The web members 212 of the truss 21 are U-shaped members. There are two top chords 211, located on the outwardly extending curved bars on both sides of the top of the U-shaped member. There is one bottom chord 213, located on the bottom horizontal bar of the U-shaped member. Preferably, the top chord 211 is reinforced with 6mm diameter steel bars, and the web members 212 and the bottom chord 213 are reinforced with 5mm diameter steel bars.

[0067] It is worth mentioning that, as is known to those skilled in the art, it is common knowledge in the field to set multiple ribs on the precast base plate 1. Therefore, in this embodiment, the number of precast composite ribs 2 is also large, with multiple precast composite ribs 2 arranged side by side on the precast base plate 1. It should be noted that this embodiment does not impose a unique limitation on the number of precast composite ribs 2 on the precast base plate 1.

[0068] The beneficial effects of this embodiment:

[0069] By employing combined ribs, variable stiffness ribs are achieved using the first concrete rib segment 22 and the second concrete rib segment 23. In the load concentration area (the area with the maximum bending moment), the second concrete rib segment 23 directly transmits force with the precast base plate 1 to meet the greater stiffness requirements. In the load non-concentration area, the first concrete rib segment 22 is used to save materials, which makes the stiffness of the overall composite slab about 1.5 times higher than that of the traditional concrete rib composite slab.

[0070] The overall structure offers a wider range of options for the precast base slab 1, including prestressed base slabs, high-performance concrete base slabs, and ordinary concrete base slabs. When using a prestressed base slab, the second concrete rib segment 23 in the load concentration area (the area with the largest bending moment) is integrally cast with or in contact with / connected to the precast base slab 1 to transfer force. This can also prevent the precast base slab 1 from arching and further reduce the thickness of the precast base slab 1.

[0071] The steel structure in the precast composite rib 2 can be either a frame or a truss 21. When using a frame, the web members 212 are fixed to the structural reinforcement of the precast base plate 1. When using a truss 21, the lower chord 213 is fixed to the structural reinforcement of the precast base plate 1, which is simple and convenient.

[0072] In this scheme, the variable stiffness precast composite rib 2, the second concrete rib segment 23 in the 30% area of ​​the mid-span (where the bending moment is large), can be precast in the factory or integrally formed with the precast base plate; in the 30% area of ​​both sides (where the bending moment is small), the first concrete rib segment 22 is precast in advance using UHPC ribs, and together with the truss 21 steel reinforcement, it forms a precast rib to achieve industrialized production; in the 10% area at the end, the steel rib segment 24 is directly made of the truss 21 steel reinforcement, which is convenient for passing through larger diameter pipelines.

[0073] The truss 21 reinforcement uses 8, 6, and 4.5 diameter steel bars (mm); the top chord 211 reinforcement uses 8mm steel bars, and the ends are welded with support bars 214 to increase the stiffness contribution of the ribs, realize the continuity of the plate, and transform the simply supported plate into a continuous plate.

[0074] In the mid-span section (where the bending moment is large), a precast concrete rib segment 23 is formed by casting a mesh plate 231 (steel mesh) to create a casting space. This space is then directly fitted onto the precast composite rib 2 in the factory to improve on-site construction efficiency.

[0075] Structural Example 2:

[0076] Please see Figure 5 and Figure 6 This embodiment discloses a prefabricated composite rib for a composite slab, comprising at least a frame, two first concrete rib segments 22, and a second concrete rib segment 23. The first concrete rib segment 22 is formed over the upper chord 211 of the frame, and the second concrete rib segment 23 is formed over the upper chord 211 of the frame and located between the two first concrete rib segments 22. The bottom of the second concrete rib segment 23 has a force-transmitting contact surface with the prefabricated base plate 1 of the composite slab, the position of which corresponds to the load concentration area of ​​the composite slab.

[0077] Specifically, the first concrete rib segment 22 and the second concrete rib segment 23 are formed by covering the upper chord 211 with UHPC. Specifically, the design is based on the span size of the composite slab. The first concrete rib segment 22 is pre-cast at 30% of the span on both sides (where the bending moment is small). The second concrete rib segment 23 is cast between the two first concrete rib segments 22. At this time, the second concrete rib segment 23 can be directly cast by temporary formwork.

[0078] Similarly, the first concrete rib segment 22 of the precast composite rib 2 and the end section of the frame form a steel rib segment 24, which is implemented as a pipeline routing section. Preferably, in a total of 10% of the area at both ends of the composite slab, the steel rib segment 24 is directly the reinforcing steel of the truss 21, which facilitates the passage of larger diameter pipelines. It should be noted that the total of 10% of the area at both ends of the composite slab is not the only limitation; firstly, it does not limit the area parameters, and secondly, it does not limit its necessity. When the space below the first concrete rib segment 22 of the precast composite rib 2 can accommodate the routing, the steel rib segment 24 can be extended and replaced by the first concrete rib segment 22, forming a structure in which the first concrete rib segment 22 and the second concrete rib segment 23 are of equal length to the span of the precast base slab 1.

[0079] Furthermore, the end of the first concrete rib segment 22 facing the second concrete rib segment 23 can be configured as a vertical surface or a sloping surface; the end of the second concrete rib segment 23 can be configured as... Figure 3 The slope shown, or implemented as Figure 4 The vertical surface plus the sloping surface shown prevents stress concentration by varying the slope.

[0080] The second concrete rib segment 23 is in contact with or connected to the precast base slab 1 for force transmission. This connection is implemented by pressing the second concrete rib segment 23 into the precast base slab 1 by 5-10mm, achieving partial interlocking with the precast base slab 1, and a burr surface can be formed on the pressed outer surface of the second concrete rib segment 23. Furthermore, when the second concrete rib segment 23 and the first concrete rib segment 22 are precast, temporary formwork can be used to form the second concrete rib segment 23, or a non-removable steel mesh formwork can be used and fixed to the truss.

[0081] As described above, the entire precast composite rib 2 is implemented as a variable stiffness composite rib consisting of 5% steel rib segment 24 + 30% first concrete rib segment 22 + 30% second concrete rib segment 23 + 30% first concrete rib segment 22 + 5% steel rib segment 24, meeting the bending moment resistance requirements of different areas of the composite slab. It should be noted that this is a preferred embodiment and is not the only one. The proportions of each area can be reasonably varied according to actual needs or span design.

[0082] Similarly, the steel structure of the prefabricated composite rib 2 includes at least a frame of upper chord 211 and web members 212; in another aspect, the steel structure of the prefabricated composite rib 2 may also include a lower chord 213, thereby forming a truss 21 structure with the frame (upper chord 211 and web members 212).

[0083] In one embodiment of this invention, the upper chord 211, lower chord 213, and web members 212 can be strip structures such as reinforcing bars, steel pipes, and structural steel. Furthermore, in this embodiment, the preferred steel structure is a truss 21, with reinforcing bars of diameters of 8, 6, and 4.5 mm. The upper chord 211 uses reinforcing bars of diameter 8 mm, with support bars 214 welded to the ends to increase the stiffness contribution of the ribs, achieving plate continuity and transforming a simply supported plate into a continuous plate.

[0084] As one implementation of this embodiment, the truss 21 or the web members 212 of the frame can be single-row web members, double-row web members, or triangular web members, etc.

[0085] As one implementation method of this embodiment, please refer to Figure 10 The web members 212 of the truss 21 are U-shaped members. There are two top chords 211, located on the outwardly extending curved bars on both sides of the top of the U-shaped member. There is one bottom chord 213, located on the bottom horizontal bar of the U-shaped member. Preferably, the top chord 211 is reinforced with 6mm diameter steel bars, and the web members 212 and the bottom chord 213 are reinforced with 5mm diameter steel bars.

[0086] The beneficial effects of this embodiment:

[0087] In this embodiment, the prefabricated composite rib 2 can be prefabricated in a factory in large quantities. The first concrete rib segment 22 and the second concrete rib segment 23 are pre-cast and formed, and transported in batches to the composite slab factory for composite slab forming. The process is simple and does not require secondary formwork or separate casting of the first concrete rib segment 22 and the second concrete rib segment 23.

[0088] Structural Example 3:

[0089] Please see Figure 7 , Figure 8 and Figure 9 This embodiment discloses a prefabricated composite rib for a composite slab, which includes at least a frame and two first concrete rib segments 22. The first concrete rib segments 22 are formed over the upper chord 211 of the frame, and a second concrete rib forming space 230 is formed between the two first concrete rib segments 22. The second concrete rib forming space 230 is integrally formed with the prefabricated base plate 1 of the composite slab to form a second concrete rib segment 23. The second concrete rib segment 23 and the prefabricated base plate 1 form a continuous force transmission structure, which is located in the load concentration area of ​​the composite slab.

[0090] Specifically, the first concrete rib segment 22 is formed by covering the upper chord 211 with UHPC. Specifically, the design is based on the span dimensions of the composite slab, with the first concrete rib segment 22 pre-cast at 30% of the span on both sides (where the bending moment is smaller), forming a second concrete rib segment forming space 230 between the two first concrete rib segments 22. Furthermore, casting mesh plates 231 are installed at the bottom and sides of the second concrete rib segment forming space 230, which is then enclosed by the casting mesh plates 231.

[0091] Specifically, the cast-in-place mesh 231 includes at least a bottom plate 2313 and side plates 2311, with the two side plates 2311 located on both sides of the upper chord 211. A space exists between the first concrete rib segment 22 and the top surface of the precast base slab 1. In a preferred embodiment of this invention, an end plate 2312 is also provided to seal this space. Therefore, the side plates 2311 on both sides, the bottom plate 2313, and the end plates 2312 together form the casting and forming space for the second concrete rib segment 23. Preferably, the elevation of the bottom plate 2313 should not be higher than the top surface elevation of the precast base slab 1.

[0092] Furthermore, a steel rib segment 24 is formed between the first concrete rib segment 22 of the precast composite rib 2 and the edge of the precast base plate 1. The steel rib segment 24 is implemented as the pipeline routing section. Preferably, in a total area of ​​10% at both ends of the composite slab, the steel rib segment 24 is directly the reinforcing steel of the truss 21, which facilitates the passage of larger diameter pipelines.

[0093] As described above, the entire precast composite rib 2 is implemented as a variable stiffness composite rib consisting of 5% steel rib segment 24 + 30% first concrete rib segment 22 + 30% second concrete rib segment 23 + 30% first concrete rib segment 22 + 5% steel rib segment 24, meeting the bending moment resistance requirements of different areas of the composite slab. It should be noted that this is a preferred embodiment and is not the only one. The proportions of each area can be reasonably varied according to actual needs or span design.

[0094] It is worth mentioning that, in this embodiment, the steel structure of the prefabricated composite rib 2 includes at least a frame of upper chord 211 and web members 212; in another aspect, the steel structure of the prefabricated composite rib 2 may also include a lower chord 213, thereby forming a truss 21 structure with the frame (upper chord 211 and web members 212).

[0095] In one embodiment of this invention, the upper chord 211, lower chord 213, and web members 212 can be strip structures such as reinforcing bars, steel pipes, and structural steel. Furthermore, in this embodiment, the preferred steel structure is a truss 21, with reinforcing bars of diameters of 8, 6, and 4.5 mm. The upper chord 211 uses reinforcing bars of diameter 8 mm, with support bars 214 welded to the ends to increase the stiffness contribution of the ribs, achieving plate continuity and transforming a simply supported plate into a continuous plate.

[0096] As one implementation of this embodiment, the truss 21 or the web members 212 of the frame can be single-row web members, double-row web members, or triangular web members, etc.

[0097] As one implementation method of this embodiment, please refer to Figure 10 The web members 212 of the truss 21 are U-shaped members. There are two top chords 211, located on the outwardly extending curved bars on both sides of the top of the U-shaped member. There is one bottom chord 213, located on the bottom horizontal bar of the U-shaped member. Preferably, the top chord 211 is reinforced with 6mm diameter steel bars, and the web members 212 and the bottom chord 213 are reinforced with 5mm diameter steel bars.

[0098] The beneficial effects of this embodiment:

[0099] In this embodiment, the prefabricated composite rib 2 can be prefabricated in a factory in large quantities. The first concrete rib segment 22 is pre-cast and formed to reserve the space 230 for the second concrete rib segment. The ribs are transported in batches to the composite slab factory for the forming of the composite slab. The second concrete rib segment 23 and the prefabricated base slab 1 are cast together, resulting in better integrity and stronger load-bearing capacity.

[0100] Furthermore, the present invention has been described in detail above with reference to the accompanying drawings and embodiments. Those skilled in the art can make various modifications to the present invention based on the above description. Therefore, certain details in the embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention shall be defined by the appended claims.

Claims

1. A composite plate, characterized in that, include: Precast base plate; The precast composite rib includes at least a frame, a first concrete rib segment, and a second concrete rib segment; The bottom of the frame is embedded and fixed to the precast base plate. The first concrete rib is formed around the upper chord of the frame, and a space is formed between the first concrete rib and the precast base plate. The second concrete rib is formed around the upper chord of the frame, and the bottom of the second concrete rib forms a continuous force transmission structure with the precast base plate. The continuous force transmission structure is located in the load concentration area of ​​the composite slab.

2. The composite plate as described in claim 1, characterized in that: The continuous force transmission structure is implemented such that the second concrete rib segment is integrally cast with the precast base plate; or, the second concrete rib segment is in contact or connected with the precast base plate for force transmission.

3. The composite plate as described in claim 1, characterized in that: The prefabricated composite rib also includes a lower chord, which is connected to the web members of the frame and forms a truss with the web members and the upper chord. The lower chord is embedded and fixed to the prefabricated base plate.

4. The composite plate as described in claim 3, characterized in that: A support rib is also provided between the end of the lower chord and the end of the upper chord.

5. The composite plate as described in claim 1, characterized in that: The location of the first concrete rib corresponds to the load-dispersed area of ​​the composite slab.

6. The composite plate as described in claim 5, characterized in that: The load concentration area is defined as the area with a large mid-span bending moment of the composite slab; the load non-concentration area is defined as the area with a small side-span bending moment of the composite slab.

7. The laminated plate as described in claim 1, 5, or 6, characterized in that: The number of the first concrete rib segments is at least two, with one second concrete rib segment located between the two first concrete rib segments.

8. The laminated plate as described in claim 7, characterized in that: A steel rib segment is formed between the first concrete rib segment of the precast composite rib and the edge of the precast base plate, and the steel rib segment is implemented as a pipeline routing section.

9. A prefabricated assembly rib for a composite slab according to any one of claims 1 to 8, characterized in that, It includes at least a frame, two first concrete ribs and one second concrete rib; the first concrete rib is formed to cover the upper chord of the frame, the second concrete rib is formed to cover the upper chord of the frame and is located between the two first concrete ribs, and the bottom of the second concrete rib has a force-transmitting contact surface with the precast bottom plate of the composite slab, the position of the force-transmitting contact surface corresponds to the load concentration area of ​​the composite slab.

10. A prefabricated assembly rib for a composite slab according to any one of claims 1 to 8, characterized in that, It includes at least a frame and two first concrete ribs; the first concrete ribs are formed to cover the upper chord of the frame, and a second concrete rib forming space is formed between the two first concrete ribs. The second concrete rib forming space is integrally formed with the precast base plate of the composite slab to form the second concrete rib. The second concrete rib and the precast base plate form a continuous force transmission structure, and the continuous force transmission structure is located in the load concentration area of ​​the composite slab.

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