Stiffening concrete rib for laminated slab, manufacturing method of stiffening concrete rib and floor system

Abstract

The invention relates to a reinforced concrete rib for a laminated slab and a manufacturing method of the reinforced concrete rib, and belongs to the technical field of building structures. The reinforced concrete rib comprises a concrete prefabricated bottom plate, a steel mesh with a V-shaped convex rib and a web member, wherein the steel mesh with the V-shaped convex rib is composed of a left steel mesh, a right steel mesh and the V-shaped convex rib in the middle of the steel meshes; the web member is formed by continuously bending a hollow steel pipe into a wave shape, wave crests of the wave-shaped web member are welded to the V-shaped protruding ribs, and wave trough parts of the wave-shaped web member are buried in the concrete prefabricated bottom plate. Longitudinal embedded steel bars and transverse embedded steel bars are further arranged in the prefabricated bottom plate. And a V-shaped groove formed by the V-shaped convex ribs can be used as a combining groove with cast-in-place laminated layer concrete, or is used for arranging a pipeline or a reinforcing rib. The composite plate is simple in structure and convenient to manufacture, has good integrity and shear resistance, and can effectively improve the bearing capacity and prolong the service life of the composite plate.

Description

Technical Field

[0001] The present invention relates to the field of building structures, and particularly to a stiffening concrete rib for a composite slab and a manufacturing method thereof. Background Art

[0002] With the acceleration of the building industrialization process, prefabricated building technologies have been widely applied. Among them, the composite slab, as an important form of prefabricated floor slab, is widely adopted due to its advantages such as fast construction speed and controllable quality. The composite slab usually consists of a precast bottom slab and a cast-in-place concrete layer, and the two form an integral structure through truss bars or other connection methods. In the composite slab structure, the truss rib is a key component to ensure the effective connection between the precast bottom slab and the cast-in-place layer, and its structural form and connection method directly affect the overall performance of the composite slab.

[0003] Currently, the common truss structures of composite slabs on the market mainly include two forms: steel bar trusses and steel pipe trusses. The steel bar truss concrete composite slab usually consists of lower chord steel bars, upper chord steel bars, and web bars connecting the two. Among them, the web bars are welded to the upper and lower chord steel bars to form an integral truss structure. Although this structure has a relatively simple manufacturing process, due to the small diameter of the steel bars, the overall stiffness of the truss is insufficient, especially in large-span application scenarios, there are obvious limitations.

[0004] In order to improve the overall stiffness and bearing capacity of the truss, the steel pipe truss concrete composite slab came into being. For example, a steel pipe truss concrete composite slab disclosed in CN115341705A includes a reinforced concrete bottom slab and a steel pipe truss. The steel pipe truss includes steel pipes and corrugated steel bars welded on both sides of the steel pipes. The troughs of the corrugated steel bars are embedded in the reinforced concrete bottom slab, and the two sides of the crests of the corrugated steel bars are welded to the steel pipes. This structure replaces the traditional upper chord steel bars with steel pipes, and to a certain extent, improves the overall stiffness of the truss.

[0005] CN115341704A further discloses a T-shaped steel pipe truss concrete composite slab. On the basis of the above structure, the crest segments of the corrugated steel bars on both sides of the steel pipes or the crest segments together with the upper web bars are bent horizontally to form the outer wing outspread steel bars of the truss upper wing, so as to improve the strength of the internal support structure of the composite slab.

[0006] CN113089920B discloses a steel pipe truss prestressed concrete composite slab, characterized in that the trough segments of the corrugated steel bars and / or the lower web bars are bent horizontally to form a bent V-shaped supporting force transmission component, and longitudinal prestressed steel bars are arranged on the bent V-shaped supporting force transmission component, and the bearing capacity of the composite slab is further improved through prestress technology.

[0007] CN118563971A discloses a truss rib and a composite truss for a composite slab. The truss rib includes a composite truss and a concrete rib. The composite truss includes at least two structural truss segments and one steel group segment. The steel group segment is connected between the two structural truss segments to form a continuous structure, and a pipe-passing space for laying out pipelines is formed.

[0008] However, the following problems still exist in the truss structure of the existing composite slab: First, in the traditional truss structure, the connection points of the web members and the upper and lower chords are usually located at the ends of the bent sections of the web members. Due to the insufficient stiffness of the bent sections of the web members themselves, deformation is likely to occur during force application, resulting in difficulty in effectively transmitting tensile and compressive forces between the upper and lower chords, seriously affecting the overall stiffness of the truss. Although some technical solutions use steel pipes to replace the upper chord steel bars to enhance the local strength, this improvement is still insufficient for the construction requirements of large-span unsupported floors and fails to fundamentally solve the problem of web member deformation.

[0009] Second, the bonding surface between the steel mesh and the concrete in the existing technology is often relatively smooth, which is likely to form an isolation layer, not only affecting the bonding strength between the new and old concretes but also posing a risk of slippage, which may endanger the safety of the building structure. Especially at the interface between the precast bottom slab and the cast-in-place layer, how to ensure their effective combination has always been a technical problem faced by the industry.

[0010] In addition, most of the existing truss structures do not fully consider the requirements of pipeline layout, resulting in the need to damage the structure when installing pipelines later, affecting the building safety and construction efficiency. At the same time, most of the truss structures in the existing technology are relatively heavy, which is not conducive to the transportation and installation of precast components, increasing the construction cost and difficulty.

[0011] Therefore, there is an urgent need for a new type of stiffening concrete rib structure for composite slabs, which can effectively solve the above technical problems, improve the overall stiffness and bearing capacity of the truss, ensure the effective combination of the precast bottom slab and the cast-in-place layer, and at the same time meet the requirements of pipeline layout and reduce self-weight. Summary of the Invention

[0012] In order to solve the technical problems of inefficient force transmission caused by web member deformation in the traditional building truss structure and the easy formation of an isolation layer on the bonding surface between the steel mesh and the concrete, and to achieve the technical effects of improving the overall stiffness of the truss and enhancing the bonding strength between the new and old concretes, the present invention provides a stiffening concrete rib for a composite slab.

[0013] The technical solution of the present invention is: to provide a stiffening concrete rib for a composite slab, including a precast concrete bottom slab and a steel mesh with V-shaped convex ribs; the steel mesh with V-shaped convex ribs is composed of steel meshes on the left and right sides and the V-shaped convex ribs in the middle of the steel mesh; it also includes a web member, which is formed by continuously bending a hollow steel pipe into a wavy shape. The wave crests of the wavy web member are welded to the V-shaped convex ribs, and the wave trough parts of the wavy web member are embedded in the precast concrete bottom slab.

[0014] A further technical solution of the present invention is that longitudinal embedded steel bars and transverse embedded steel bars are also arranged at intervals in the precast concrete bottom slab. The transverse embedded steel bars pass through above the included angle at the bending part at the bottom of the corrugated web member, and the transverse embedded steel bars are located on one side of the longitudinal embedded steel bars close to the lower surface of the precast bottom slab.

[0015] A further technical solution of the present invention is that it further includes cast-in-place composite layer reinforced concrete, and the cast-in-place composite layer concrete is poured on the precast concrete bottom slab at the construction site to form a composite slab.

[0016] A further technical solution of the present invention is that the steel mesh includes a base material composed of a ductile metal sheet and a first row of mesh holes and a second row of mesh holes located on both sides. The first row of mesh holes and the second row of mesh holes are arranged in a staggered manner in the thickness direction of the base material.

[0017] A further technical solution of the present invention is that both the first row of mesh holes and the second row of mesh holes are parallelograms with an inclined angle; the inclined angles of the first row of mesh holes and the second row of mesh holes can be the same or different.

[0018] A further technical solution of the present invention is that the projections of the first row of mesh holes and the second row of mesh holes on the plane are arranged in a staggered manner.

[0019] A further technical solution of the present invention is that the diameter of the corrugated web member is 8 mm - 25 mm.

[0020] A further technical solution of the present invention is that the maximum width at the opening of the V-shaped groove formed by the V-shaped convex ribs does not exceed 80% of the diameter of the corrugated web member.

[0021] A further technical solution of the present invention is that high-strength filling material is poured into the steel mesh with V-shaped convex ribs to form an upper chord stiffening concrete rib, and the high-strength filling material can be concrete, grouting material or mortar.

[0022] A further technical solution of the present invention is that the V-shaped groove formed by the V-shaped convex ribs in the middle of the upper chord stiffening concrete rib serves as a bonding groove for the cast-in-place composite layer reinforced concrete.

[0023] A further technical solution of the present invention is that pipes, wires or reinforcing bars are arranged in the V-shaped groove formed by the V-shaped convex ribs in the middle of the upper chord stiffening concrete rib.

[0024] A further technical solution of the present invention is that a new and old concrete strengthened bonding surface is formed between the outer surface of the steel mesh with V-shaped convex ribs and the cast-in-place composite layer reinforced concrete.

[0025] A further technical solution of the present invention is that multiple filling and weight-reducing bodies are integrally embedded in the precast concrete floor slab, or the multiple filling and weight-reducing bodies are placed on the precast concrete floor slab at the construction site, or are suspended on the precast concrete floor slab by legs; the filling and weight-reducing body can be a solid structure or a hollow structure, and can be a foam product, a plastic product or a hollow steel mesh; the centers of the filling and weight-reducing bodies are connected in a net shape.

[0026] The present invention also provides a manufacturing method for the stiffening concrete rib and the stiffening concrete rib composite slab for the above-mentioned composite slab, which includes the following steps:

[0027] ① Bend the steel mesh (2) with V-shaped convex ribs into a trough-shaped mesh groove with an upward opening, and place it on a horizontal plane with the opening facing upward;

[0028] ② Vertically fix the manufactured wavy web member (3) on the V-shaped convex rib (22) and weld it firmly;

[0029] ③ Pour high-strength grouting material into the upward-opening steel mesh (2) to form the upper chord stiffening concrete rib (24), forming a truss;

[0030] ④ Turn the trusses 180 degrees up and down, with the upper chord stiffening concrete rib (24) on top and the wavy web member (3) at the bottom;

[0031] ⑤ Arrange the longitudinal embedded steel bars (11) and transverse embedded steel bars (12) in the precast floor slab (1) on the formwork to form a steel bar grid. At the same time, connect the lower part of the web member (3) of each truss to the steel bar grid and then pour the concrete of the precast floor slab (1);

[0032] ⑥ Transport the concrete precast floor slab (1) that has reached the strength to the construction floor surface. After binding the steel bars in the cast-in-place composite layer, pour the cast-in-place composite layer reinforced concrete (4).

[0033] The present invention also provides a floor slab, which includes the stiffening concrete rib for the composite slab as described above, and also includes beams, walls or columns that support the concrete precast floor slab (1) component.

[0034] The beneficial effects of the present invention are as follows:

[0035] 1. The steel mesh described in the present invention is formed by vertically punching and horizontally stretching a steel plate to form a spatial concave-convex mesh. The steel mesh is bent into a trough-shaped mesh groove with an upward opening, and high-strength grouting material is poured into it to form the upper chord stiffening concrete rib. The advantage is that the steel mesh with spatial concave-convex mesh on the surface and the high-strength grouting material form a mutual mechanical bite, and the finished surface has a natural rough surface without the need for later surface roughening; when the steel mesh with concave-convex mesh is combined with the later-cast composite layer concrete, no separation layer will be generated, which will cause slippage, effectively solving the problem of the reduction of concrete strength caused by the separation layer in the traditional structure.

[0036] 2. The steel mesh with a three-dimensional concave-convex mesh surface itself also strengthens the internal high-strength grouting material, avoiding damage to the structure strength caused by inevitable knocking during construction and stacking a large amount of building materials on the stiffening concrete ribs, which may affect the structural strength.

[0037] 3. The closely spaced steel mesh has a wrapping effect of three-phase constraint, which can improve the longitudinal compressive force of the concrete ribs, further increase the unsupported span of the composite slab, and meet the construction requirements of large-span unsupported floor slabs.

[0038] 4. The steel mesh with V-shaped convex ribs is adopted in the present invention. The steel mesh and the V-shaped convex ribs are integrally formed by a machine, greatly enhancing the strength. At the same time, due to the existence of the solid convex ribs, direct welding between the web members and the steel mesh is avoided. The hollow web members are welded to the steel plate of the V-shaped solid convex ribs, and it is not easy to produce welding quality problems such as penetration, fundamentally solving the problem of web member deformation in the traditional structure.

[0039] 5. There is a V-shaped groove in the middle of the upper chord stiffening concrete rib of the present invention parallel to the direction of the web members, which serves as a combined groove for the cast-in-place composite layer reinforced concrete. The cast-in-place layer concrete is embedded in the V-shaped groove, greatly enhancing the strength of the bonding surface between the new and old concretes; combined with the rough surface formed by the steel mesh with spatial concave-convex mesh, it jointly ensures that the bonding surfaces of the new and old concretes on the upper surface, both side surfaces, and bottom surface will not be displaced, slipped, or cracked, meeting the assumption of infinite rigidity of the floor slab plane.

[0040] 6. Reinforcing bars can be arranged in the V-shaped groove of the present invention. The reinforcing bars can be ordinary reinforcing bars or prestressed reinforcing bars, which play a role in further strengthening the stiffness and strength of the V-shaped convex ribs.

[0041] 7. Pipes or wires can be arranged in the V-shaped groove of the present invention. Relevant pipes and wires can be pre-embedded in the factory, and then filling protection materials or functional materials such as high-strength grouting materials, fireproof, anti-corrosion, and heat-insulating materials can be poured in the V-shaped groove. At this time, the V-shaped groove is used as a pipeline groove, which can play a good role in protecting the pipelines during the pouring of the cast-in-place composite layer concrete, preventing the pipelines from being displaced and damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic cross-sectional view of the stiffening concrete rib for the composite slab;

[0043] Figure 2 It is a schematic cross-sectional view of the steel mesh with V-shaped convex ribs;

[0044] Figure 3 It is an enlarged schematic view of the V-shaped convex rib of the steel mesh with V-shaped convex ribs;

[0045] Figure 4 It is a schematic cross-sectional view of another embodiment of the steel mesh with V-shaped convex ribs;

[0046] Figure 5Schematic cross-sectional view of another embodiment of the steel mesh with V-shaped ribs;

[0047] Figure 6 Schematic view of the composite slab structure formed by casting the in-situ composite layer concrete on the precast concrete bottom slab;

[0048] Figure 7 Front view of the steel mesh with V-shaped ribs;

[0049] Figure 8 Perspective view of the steel mesh with V-shaped ribs;

[0050] Figure 9 Schematic view of another perspective of the combination of the wavy web members and the V-shaped ribs;

[0051] Figure 10 Dimension schematic view of a specific embodiment of the V-shaped groove formed by the V-shaped ribs;

[0052] Figure 11 Schematic view of the reinforcing ribs arranged in the V-shaped groove formed by the V-shaped ribs. Specific embodiments

[0054] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and by means of embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without any creative work fall within the scope of protection of the present invention.

[0055] Embodiment 1

[0056] Please refer to Figure 1 、 Figure 2 、 Figure 3 ; A stiffening concrete rib for a composite slab, comprising a precast concrete bottom slab 1 and a steel mesh with V-shaped ribs 2; the steel mesh with V-shaped ribs is composed of steel meshes 21 on the left and right sides and V-shaped ribs 22 in the middle of the steel mesh; it further includes web members 3, and the web members are formed by continuously bending a hollow steel pipe into a wavy shape. The wave crests of the wavy web members are welded to the V-shaped ribs, and the wave trough parts of the wavy web members are buried in the precast concrete bottom slab.

[0057] Among them, the precast concrete bottom slab refers to a precast concrete substrate in the factory, which can be cast and formed with C40 concrete, serving as the bearing foundation of the composite slab and providing a stable anchoring matrix for the web members.

[0058] The steel mesh with V-shaped ribs refers to a three-dimensional steel mesh structure formed by stamping process. It can be integrally formed by punching and stretching a steel plate.

[0059] The corrugated web member refers to a periodic undulating structure formed by continuously bending a hollow steel pipe through a rolling forming device. The pipe diameter can be determined in combination with the span requirements. By continuous bending, multiple wave crests and wave troughs are formed, changing the load transfer path from a single point to a multi-point distribution and improving the stress concentration problem.

[0060] Specifically, the concave-convex mesh holes on both sides of the steel mesh with V-shaped convex ribs form a three-dimensional bite with the cast-in-place concrete, preventing interface slippage. The top plane of the V-shaped convex rib provides a precise positioning surface for the welding of the web member, ensuring the accurate welding position of the wave crest. The continuous bending structure of the hollow steel pipe web member forms multiple rigid fulcrums longitudinally. When the wave crest is welded to the V-shaped convex rib, a force transmission node of the truss upper chord is formed, and when the wave trough is embedded in the concrete of the precast floor slab, a lower chord anchoring point is formed. This two-way strengthening structure enables the load to be evenly transmitted to the precast floor slab through the wave crests and wave troughs of the web member, avoiding deformation caused by excessive local stress. The concrete in the precast floor slab wraps the wave trough section of the web member, forming a mechanical anchoring effect and restricting the displacement of the web member.

[0061] Longitudinal embedded steel bars 11 and transverse embedded steel bars 12 are also arranged at intervals in the precast concrete floor slab. The transverse embedded steel bars pass through above the included angle at the bottom bending of the corrugated web member, and the transverse embedded steel bars are located on the side of the longitudinal embedded steel bars closer to the lower surface of the precast floor slab.

[0062] Among them, the longitudinal embedded steel bars refer to the steel bars arranged parallel to the length direction of the precast floor slab. Specifically, it can be realized by using deformed steel bars with a diameter of 8 - 16 mm or prestressed tendons with a diameter of 5 - 16 mm, which are used to resist longitudinal bending deformation. The transverse embedded steel bars refer to the steel bars arranged parallel to the width direction of the precast floor slab. Specifically, it can be realized by using steel bars with a diameter of 4 - 12 mm, and they are arranged close to the lower surface of the floor slab to restrict the displacement of the wave trough of the web member.

[0063] Specifically, the longitudinal steel bars and the transverse steel bars cross to form a spatial grid. The transverse steel bars pass through the included angle at the wave trough bending of the web member, so that the wave trough nodes of the web member form a mechanical bite with the steel bar grid. When the web member bears the load, the transverse steel bars transfer the longitudinal stress of the web member to the longitudinal steel bars, and at the same time, the longitudinal steel bars form a transverse restraint on the wave trough of the web member through the transverse steel bars, thereby reducing the local deformation of the bending section of the web member. The up-and-down position relationship between the longitudinal steel bars and the transverse steel bars makes the transverse steel bars closer to the tensile area of the floor slab, further strengthening the load transfer path between the web member and the precast floor slab.

[0064] Figure 4 、 Figure 5 shows two other deformation methods of the steel mesh with V-shaped convex ribs. In Figure 4 , the two side edges of the steel mesh with V-shaped convex ribs are folded inwards. Figure 5 In, after the two side edges of the steel mesh with V-shaped convex ribs are folded inwards, they are further folded downwards to form flanges 23. These two methods make the combination effect better when pouring concrete inside the steel mesh.

[0065] Please refer to Figure 6 , this application further proposes cast-in-place composite layer reinforced concrete, which forms a composite slab structure by casting on-site at the construction site on a precast concrete floor slab.

[0066] Among them, the cast-in-place composite layer reinforced concrete refers to a cast-in-place structural layer composed of concrete and steel bars, which forms an integral stress system by combining with the precast floor slab through on-site casting technology. For example, concrete with a strength grade of C30-C50 can be used in combination with HRB400 grade steel bars for casting. This layer covers the steel mesh with V-shaped ribs on the upper surface of the precast floor slab, and uses the rough surface 27 formed by the concave and convex mesh holes on the surface of the steel mesh to generate a mechanical biting effect with the newly cast concrete.

[0067] Specifically, as the base layer of the composite slab, the steel mesh with V-shaped ribs arranged on the surface of the precast floor slab forms an embedded interface for the concrete of the cast-in-place layer through the concave and convex mesh hole structure formed by punching and stretching. During the casting process, the cast-in-place concrete penetrates into the mesh holes of the steel mesh and wraps the V-shaped ribs, and a composite structure that interpenetrates each other is formed after curing. This structure realizes the coordinated transfer of stress between the upper and lower layers through the binding connection between the embedded steel bar grid inside the precast floor slab and the steel bars of the cast-in-place layer, and at the same time uses the biting effect between the steel mesh and the concrete to eliminate the slip risk of the bonding surface.

[0068] Compared with the prior art, the surface of the traditional precast composite slab needs to be manually roughened to enhance the bonding force, but the uneven roughening depth is likely to cause local isolation layers. In this solution, the steel mesh with concave and convex mesh holes is directly used as the surface layer of the precast floor slab, and its mesh hole structure naturally forms a rough bonding surface during the casting process without secondary processing. In addition, the mechanical biting strength between the steel mesh and the cast-in-place concrete is significantly higher than the frictional resistance of the conventional roughened surface, fundamentally avoiding the phenomenon of delamination and slipping.

[0069] Through the above technical solution, this application solves the technical defect that an isolation layer is likely to occur at the bonding surface between the precast component and the cast-in-place layer, and realizes the seamless bonding of the new and old concretes. The biting effect between the steel mesh and the cast-in-place layer makes the composite slab form an integral stress system, effectively improving the shear resistance and the structural integrity, while retaining the dimensional accuracy advantage of the factory precast components. This structure does not require additional treatment of the bonding surface during the construction process, simplifies the process flow and reduces the risk of quality hazards.

[0070] Please refer to Figure 7 、 Figure 8 , Figure 7 、 Figure 8 are respectively the front view and the perspective view of the steel mesh with V-shaped ribs in a preferred embodiment.

[0071] The steel mesh 2 with V-shaped convex ribs includes a base material 210 made of a ductile metal sheet, and a first row of mesh holes 211 and a second row of mesh holes 212 on both sides. The first row of mesh holes and the second row of mesh holes are arranged in a staggered manner in the thickness direction of the base material.

[0072] Among them, the base material made of a ductile metal sheet refers to a thin sheet made of a metal material with strong plastic deformation ability. Specifically, low-carbon steel or aluminum alloy materials can be used to ensure that the steel mesh does not break during the bending process. The first row of mesh holes and the second row of mesh holes being arranged in a staggered manner in the thickness direction of the base material means that in the direction perpendicular to the surface of the metal sheet, the positions of the two rows of mesh holes are offset from each other. In this embodiment, it is achieved by tearing the upper and lower parts of the base material separately in the machine.

[0073] The staggered arrangement of the first row of mesh holes and the second row of mesh holes forms a multi-directionally penetrating channel in space. When high-strength grout is injected into the steel mesh, the slurry is embedded into the mesh holes on both sides from different directions and forms a multi-dimensional mechanical bite after curing. Since the staggered mesh holes form three-dimensional staggered anchoring points in the thickness direction, it effectively increases the contact area between the slurry and the steel mesh, avoiding the insufficient bonding force caused by the unidirectional embedding of traditional flat mesh holes. At the same time, the continuous concave and convex surfaces formed by the staggered mesh holes make the surface of the steel mesh have a natural rough texture, eliminating the hidden danger of interface slip. This solution forms a three-dimensional staggered anchoring structure by arranging two rows of mesh holes in a staggered manner in the thickness direction, enabling the slurry to be embedded into the mesh holes in multiple spatial dimensions, significantly enhancing the interface bonding strength, and avoiding the appearance of an isolation layer on the bonding surface.

[0074] This application further proposes a technical solution in which both the first row of mesh holes and the second row of mesh holes are parallelograms with an inclined angle, and the inclined angles of the two can be the same or different.

[0075] The design forms an asymmetric concave and convex interface by changing the inclined direction of the mesh hole edge, thereby enhancing the mechanical resistance received when the concrete flows.

[0076] This application further proposes that the first row of mesh holes and the second row of mesh holes are arranged in a staggered manner in the plane projection.

[0077] Among them, the plane projection staggered arrangement means that the long sides of the two rows of mesh holes are not on the same straight line in the plane projection. This arrangement method forms staggered anchoring nodes in the spatial distribution of the mesh holes, further enhancing the mechanical bite effect between the steel mesh and the concrete.

[0078] Please refer to Figure 9 , Figure 9 for another perspective schematic diagram of the combination of the wavy web member and the V-shaped convex rib 22.

[0079] Figure 9Among them, the diameter of the corrugated web member is 12 mm, which is within the range of 8 mm - 25 mm, and can meet the structural strength requirements without excessively increasing the self-weight.

[0080] Please refer to Figure 10 , Figure 10 It is a schematic diagram of the dimensions of a specific embodiment of the V-shaped groove formed by the V-shaped convex ribs.

[0081] Figure 10 Among them, the maximum width at the opening of the V-shaped groove formed by the V-shaped convex ribs is 8.82 mm, which does not exceed 80% of the diameter of the corrugated web member (i.e., 12 mm × 80% = 9.6 mm). This design enables the V-shaped groove to effectively form an anchoring effect with the cast-in-place concrete, and at the same time, it will not reduce the stiffness of the V-shaped convex ribs due to an overly large opening.

[0082] The depth of the V-shaped groove is 9.53 mm, and the wall thickness of the V-shaped convex rib is 0.5 mm. The included angle of the V-shaped groove is 25°.

[0083] Please refer to Figure 11 , high-strength filling material 24 is poured into the steel mesh with V-shaped convex ribs to form the upper chord stiffening concrete rib. The high-strength filling material uses a slightly expanding grouting material with a strength grade of C50, and its 28-day compressive strength reaches 50 MPa. It has good fluidity and slightly expanding properties, and can completely fill the internal space of the steel mesh and be closely combined with the steel mesh.

[0084] Reinforcing bars 26 can also be arranged in the V-shaped groove formed by the V-shaped convex ribs in the middle of the upper chord stiffening concrete rib. The reinforcing bars adopt HRB400 grade steel bars with a diameter of 8 mm, are longitudinally arranged along the V-shaped groove, and extend 50 mm out of the V-shaped groove at both ends, and are tied and connected with the cast-in-place layer steel bars, further enhancing the connection strength between the upper chord stiffening concrete rib and the cast-in-place layer.

[0085] The outer surface of the steel mesh with V-shaped convex ribs and the cast-in-place composite layer reinforced concrete form a new and old concrete strengthening joint surface.

[0086] In one embodiment, a plurality of filling and weight-reducing bodies are integrally embedded on the precast concrete floor slab. The filling and weight-reducing bodies adopt polystyrene foam products with a density of 20 kg / m 3 , with a frustum cone shape, a bottom diameter of 300 mm, a top diameter of 200 mm, and a height of 80 mm. The filling and weight-reducing bodies are fixed through plastic anchor fittings embedded in the precast concrete floor slab. The height of the anchor fittings is 30 mm, and the diameter is 10 mm. One anchor fitting is arranged at each of the four corners of each filling and weight-reducing body. The center points of the filling and weight-reducing bodies are connected in a mesh pattern, and the center point spacing is 500 mm × 500 mm, forming a regular weight-reducing grid.

[0087] Embodiment 2

[0088] A manufacturing method for a stiffening concrete rib for a composite slab and a composite slab with stiffening concrete ribs, comprising the following steps:

[0089] ① Bend the steel mesh with V-shaped ribs into a trough-shaped mesh groove with an upward opening, and place it on a horizontal plane with the opening facing upward;

[0090] ② Vertically fix the fabricated corrugated web members to the V-shaped ribs and weld them firmly;

[0091] ③ Pour high-strength grouting material into the upward-opening steel mesh to form an upper chord stiffening concrete rib, forming a truss;

[0092] The high-strength grouting material uses a commercial slightly expanding grouting material with a strength grade of C50, a water-cement ratio of 0.35, and a mixing time of 5 minutes to ensure that the grouting material is fully mixed evenly. Slowly pour the mixed grouting material into the upward-opening steel mesh, and the pouring height is flush with the upper edge of the steel mesh. Gently vibrate with a vibrating rod to ensure that the grouting material fully fills the internal space of the steel mesh without leaving air bubbles. After pouring, cure for 24 hours at an ambient temperature of 20°C to make the grouting material initially solidify, forming an upper chord stiffening concrete rib, which together with the corrugated web members constitutes a truss structure.

[0093] ④ Turn each truss 180 degrees up and down, with the upper chord stiffening concrete rib on top and the corrugated web members on the bottom;

[0094] After the strength of the grouting material reaches the design requirements (generally after 24 hours, the compressive strength reaches above 15 MPa), use a hoisting device to carefully turn the truss 180 degrees so that the upper chord stiffening concrete rib is on the top and the corrugated web members are on the bottom. Pay attention to protecting the truss from damage during the turning process, especially the trough part of the corrugated web members, because this part will be buried in the precast bottom slab. Place the turned truss temporarily on the support frame for the next operation.

[0095] ⑤ Arrange the longitudinal embedded steel bars and transverse embedded steel bars in the precast bottom slab on the formwork to form a steel bar grid, and at the same time connect the lower part of the web members of each truss to the steel bar grid and then pour the concrete of the precast bottom slab;

[0096] On a flat formwork, first apply a release agent, and then arrange the longitudinal embedded steel bars and transverse embedded steel bars according to the design requirements. The longitudinal embedded steel bars use HRB400 grade steel bars with a diameter of 10 mm and a spacing of 200 mm; the transverse embedded steel bars also use HRB400 grade steel bars with a diameter of 8 mm and a spacing of 150 mm. Tie the intersection points of the steel bars firmly with iron wire to form a steel bar grid. Then place the turned truss above the steel bar grid so that the trough part of the corrugated web members intersects with the steel bar grid, and tie and connect the corrugated web members to the steel bar grid with iron wire. Ensure that the transverse embedded steel bars pass through above the included angle at the bottom bending of the corrugated web members and maintain a clear distance of 10 mm from the corrugated web members.

[0097] After the binding is completed, pour the concrete for the precast floor slab. The concrete strength grade is C30, the slump is 160 mm, and the pouring thickness is 60 mm. During pouring, ensure that the concrete fully wraps the trough part of the corrugated web members, vibrate it densely with a vibrating rod, and finish the surface with a wooden float. Cure for 7 days under the condition of an ambient temperature of 20 °C to make the concrete strength reach the design requirements (generally more than 70% of the 28-day strength).

[0098] ⑥ Transport the concrete precast floor slab that has reached the strength to the construction site floor. After binding the steel bars in the cast-in-place composite layer, pour the reinforced concrete for the cast-in-place composite layer.

[0099] When the concrete strength of the precast floor slab reaches the design requirements, use a hoisting device to carefully hoist and transport the precast floor slab to the construction site. Place the precast floor slab on the supporting structure (such as beams, walls or columns) at the construction site according to the design position, and adjust its levelness and elevation. Bind the steel bar mesh in the cast-in-place composite layer above the precast floor slab as required by the design. The steel bars are of HRB400 grade, with a diameter of 12 mm and a spacing of 200 mm, forming a two-way steel bar mesh. The steel bar mesh is tied and connected with the reinforcing bars in the V-shaped groove of the upper chord stiffening concrete rib on the precast floor slab to ensure good bonding between the new and old concretes.

[0100] Before pouring the reinforced concrete for the cast-in-place composite layer, first clean the dust and sundries on the surface of the precast floor slab and sprinkle it with water to moisten it, but there should be no accumulated water. The strength grade of the concrete for the cast-in-place layer is C35, the slump is 180 mm, and the pouring thickness is 100 mm. During pouring, ensure that the concrete fully fills the V-shaped groove and around the steel mesh, vibrate it densely with a vibrating rod, and finish the surface with a wooden float. Cure for 14 days under the condition of an ambient temperature of 20 °C to make the concrete strength reach the design requirements.

[0101] Embodiment 3

[0102] A floor slab includes the stiffening concrete ribs for the composite slab described in Embodiment 1, and also includes beams, walls or columns that support the concrete precast floor slab components.

[0103] In this floor slab system, the component that supports the concrete precast floor slab is a reinforced concrete beam. The strength grade of the beam is C40, the cross-sectional size is 250 mm × 500 mm, and the reinforcement is 4 longitudinal steel bars of HRB400 grade with a diameter of 20 mm and stirrups with a diameter of 8 mm and a spacing of 200 mm. Both ends of the concrete precast floor slab are placed on the beam, and the placement length is 40 mm. A 10-mm-thick rubber bearing is provided between the precast floor slab and the beam to reduce stress concentration.

[0104] The floor slab has a span of 6 meters and a width of 12 meters, and is composed of 10 precast bottom slabs spliced together. The joint width between adjacent precast bottom slabs is 20mm. Connecting steel bars with a diameter of 12mm are arranged in the joint, with a spacing of 300mm. Both ends of the connecting steel bars extend into adjacent precast bottom slabs by 150mm respectively and are tied to the steel bar mesh in the precast bottom slabs. A slightly expanding grouting material with a strength grade of C40 is poured at the joint to ensure the structural integrity at the joint.

[0105] The thickness of the cast-in-place composite layer on the upper part of the floor slab is 100mm, and a two-way steel bar mesh is arranged inside. The steel bars are of HRB400 grade, with a diameter of 12mm and a spacing of 200mm. The concrete strength grade of the cast-in-place layer is C35, which forms an integral structure with the stiffening concrete ribs on the precast bottom slab to jointly bear the load of the floor slab.

[0106] The design load of this floor slab is: dead load 2.5kN / m 2 , live load 2.0kN / m 2 . Through finite element analysis, the maximum deflection of this floor slab under the design load is L / 480 (L is the span), which is less than the allowable L / 250 in the code and meets the service function requirements. The seismic performance of the floor slab is good, and it can still maintain the structural integrity under the action of an 8-degree earthquake without obvious damage.

[0107] The construction technology of the floor slab is simple and the construction period is short. After the precast bottom slabs are precast in the factory and transported to the site, only simple installation and cast-in-place layer pouring work are required, which greatly reduces the on-site wet operation volume and formwork support workload, improves the construction efficiency, and reduces the construction cost. At the same time, due to the adoption of the stiffening concrete rib structure, the self-weight of the floor slab is reduced by about 20% compared with the traditional cast-in-place floor slab, saving materials and energy, and meeting the requirements of green buildings.

[0108] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. Stiffening concrete ribs for laminated plates, characterized in that, Including: precast concrete bottom slab (1), steel mesh with V-shaped ribs (2); the steel mesh with V-shaped ribs (2) is composed of steel meshes (21) on the left and right sides and V-shaped ribs (22) in the middle of the steel mesh; It further includes web members (3), and the web members (3) are formed by continuously bending a hollow steel pipe into a wavy shape. The wave crests of the wavy web members (3) are welded to the V-shaped ribs (22), and the wave trough parts of the wavy web members (3) are embedded in the precast concrete bottom slab (1).

2. The stiffening concrete rib for the laminated slab according to claim 1, characterized in that: Longitudinal embedded steel bars (11) and transverse embedded steel bars (12) are also arranged at intervals in the precast concrete bottom slab (1). The transverse embedded steel bars (12) pass through from above the included angle at the bottom bending of the wavy web members (3), and the transverse embedded steel bars (12) are located on the side of the longitudinal embedded steel bars (11) close to the lower surface of the precast bottom slab (1).

3. The stiffening concrete rib for the laminated slab according to claim 1, wherein: It further includes cast-in-place composite layer reinforced concrete (4), and the cast-in-place composite layer concrete is poured on the precast concrete bottom slab (1) at the construction site to form a composite slab.

4. The stiffening concrete rib for the laminated slab according to claim 1, characterized in that: The steel mesh (21) includes a base material (210) composed of a ductile metal sheet and first row of mesh holes (211) and second row of mesh holes (212) on both sides. The first row of mesh holes (211) and the second row of mesh holes (212) are arranged in a staggered manner in the thickness direction of the base material.

5. The stiffening concrete rib for the laminated slab according to claim 4, characterized in that: Both the first row of mesh holes (211) and the second row of mesh holes (212) are parallelograms with an inclined angle; the inclined angles of the first row of mesh holes (211) and the second row of mesh holes (212) can be the same or different.

6. The stiffening concrete rib for the laminated slab according to claim 4, characterized in that: The projections of the first row of mesh holes (211) and the second row of mesh holes (212) on the plane are arranged in a staggered manner.

7. The stiffening concrete rib for the laminated slab according to claim 1, wherein: The diameter of the wavy web members (3) is 8 mm - 25 mm.

8. The stiffening concrete rib for the laminated slab according to claim 1, characterized in that: The maximum width at the opening of the V-shaped groove (25) formed by the V-shaped ribs (22) does not exceed 80% of the diameter of the wavy web members (3).

9. The stiffening concrete rib for the laminated slab according to claim 8, characterized in that: High-strength filling material is poured into the steel mesh with V-shaped ribs (2) to form an upper chord stiffening concrete rib (24), and the high-strength filling material can be concrete, grouting material or mortar.

10. The stiffening concrete rib for the laminated slab according to claim 9, characterized in that: The V-shaped groove (25) formed by the V-shaped ribs (22) in the middle of the upper chord stiffening concrete rib (24) serves as a combined groove with the cast-in-place composite layer reinforced concrete (4).

11. The stiffening concrete rib for the laminated slab according to claim 8, wherein: Tubes, wires or reinforcing bars (26) are arranged in the V-shaped groove (25) formed by the V-shaped ribs (22) in the middle of the upper chord stiffening concrete rib (24).

12. The stiffening concrete rib for the laminated slab according to claim 1, wherein: A new and old concrete strengthened joint surface (27) is formed between the outer surface of the steel mesh with V-shaped ribs (2) and the cast-in-place composite layer reinforced concrete (4).

13. The stiffening concrete rib for the laminated slab according to claim 1, characterized in that: Multiple filling and weight-reducing bodies are integrally embedded on the precast concrete bottom slab (1), or the multiple filling and weight-reducing bodies are placed on the precast concrete bottom slab (1) at the construction site or are suspended on the precast concrete bottom slab (1) by legs; the filling and weight-reducing bodies can be solid structures or hollow structures, can be foam products or plastic products or hollow steel meshes; the central points of the filling and weight-reducing bodies are connected in a net shape.

14. A manufacturing method of a stiffening concrete rib for a laminated slab and a laminated slab with a stiffening concrete rib, characterized in that, Including the following steps: ① Bend the steel mesh (2) with V-shaped ribs into a trough-shaped mesh groove with the opening facing upward, and place it upward on a horizontal plane; ② Vertically fix the made wavy web members (3) to the V-shaped ribs (22) and weld them firmly; ③ Pour high-strength grouting material into the upward-opening steel mesh (2) to form the upper chord stiffening concrete rib (24), thus forming a truss; ④ Turn each truss 180 degrees up and down, with the upper chord stiffening concrete rib (24) on top and the wavy web member (3) at the bottom; ⑤ Arrange the longitudinal embedded steel bars (11) and transverse embedded steel bars (12) in the precast floor slab (1) on the formwork to form a steel bar grid. At the same time, connect the lower part of the web member (3) of each truss to the steel bar grid and then pour the concrete of the precast floor slab (1); ⑥ Transport the concrete precast floor slab (1) that has reached the required strength to the construction site floor. After tying the steel bars in the cast-in-place composite layer, pour the cast-in-place composite layer reinforced concrete (4).

15. A floor slab, characterized in that: It includes the stiffening concrete rib for the composite slab described in any one of claims 1-13, and also includes a beam or wall or column that supports the concrete precast floor slab (1) component.

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