A self-supporting precast concrete composite slab

Abstract

The utility model provides a kind of exempt from support prefabricated concrete composite slab, including prefabricated bottom plate and built-in reinforcing mesh sheet, and several steel plate chord single web truss partially embedded in prefabricated bottom plate, the steel plate chord single web truss includes upper chord steel plate, lower chord steel plate and the web of connecting upper chord steel plate and lower chord steel plate, upper chord steel plate, lower chord steel plate are steel material, and web is reinforcing steel, the steel plate chord single web truss is connected with prefabricated bottom plate by partially embedded and fixed mode;Longitudinal reinforcement and transverse reinforcement are arranged in the prefabricated bottom plate, and form reinforcing mesh structure.The steel plate chord single web truss composite slab provided by the utility model can greatly improve the bending stiffness of prefabricated concrete composite slab, and when installing post-installed cast-in-place composite slab face concrete cast-in-place layer, temporary support does not need to be set under prefabricated plate in span.

Description

Technical Field

[0001] This utility model relates to the field of prefabricated building components, specifically a support-free precast concrete composite slab. Background Technology

[0002] Most existing prefabricated reinforced concrete horizontal floor slabs adopt truss reinforced concrete composite slabs. Truss reinforced concrete composite slabs are composed of a precast base slab and truss reinforcement, which are installed on site and a cast-in-place composite layer is poured to form an integral load-bearing floor slab structure. The truss reinforcement is a triangular truss welded from the top chord reinforcement, bottom chord reinforcement and web reinforcement, which is used to connect the precast slab and the cast-in-place composite layer to enhance the overall load-bearing performance.

[0003] Its disadvantage is that the truss reinforcement mainly serves to connect the cast-in-place layers and has limited effect on improving the stiffness of the composite slab. Before the cast-in-place composite layer reaches the design strength, full-span support needs to be set under the precast slab, which is not much different from the construction measures of cast-in-place floor slabs and cannot give full play to the advantages of prefabricated buildings.

[0004] Therefore, based on the on-site working conditions, a support-free precast concrete composite slab was proposed to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a support-free precast concrete composite slab to solve the problems mentioned in the background art.

[0006] To solve the aforementioned technical problems, the present invention adopts the following technical solution: a support-free precast concrete composite slab, comprising a precast base slab and an internal steel mesh, and several steel plate chord single-web trusses partially embedded in the precast base slab. Each steel plate chord single-web truss includes an upper chord steel plate, a lower chord steel plate, and web reinforcement connecting the upper and lower chord steel plates. Both the upper and lower chord steel plates are made of steel, and the web reinforcement is made of reinforcing steel. The steel plate chord single-web truss is connected to the precast base slab through partial pre-embedding and embedding. Longitudinal and transverse reinforcing bars are arranged within the precast base slab to form a steel mesh structure.

[0007] Preferably, the steel mesh formed by the longitudinal and transverse steel bars in the precast base plate is connected to the lower chord steel plate of the single-web steel plate truss by binding.

[0008] Preferably, the steel mesh formed by the longitudinal and transverse steel bars in the precast base plate is connected to the lower chord steel plate of the single-web steel plate truss by welding.

[0009] Preferably, the longitudinal and transverse reinforcing bars in the precast base slab are prestressed tendons or ordinary reinforcing bars, which can be completely embedded inside the precast base slab or extend out to a certain length.

[0010] Preferably, the cross-sectional shape of the upper chord steel plate and the lower chord steel plate is rectangular, circular or I-shaped.

[0011] Preferably, the angle between the web reinforcement and the upper and lower chord plates is 30°-60°.

[0012] Preferably, the upper and lower edges of the precast base plate are chamfered, and adjacent precast concrete composite slabs are spliced ​​together by the chamfers.

[0013] Preferably, polymer mortar is provided inside the chamfer to prevent mortar leakage at the joint.

[0014] Preferably, the surface of the precast base plate is roughened to increase the adhesion to the subsequent cast-in-place concrete layer.

[0015] Preferably, the precast concrete composite slab further includes a release agent layer disposed at the bottom of the precast base plate, the release agent layer being used to facilitate demolding during the production process of the precast concrete composite slab.

[0016] The present invention has the following beneficial effects:

[0017] 1. The steel plate chord single-web truss used in this utility model has the upper chord steel plate and the lower chord steel plate embedded in the cast-in-place layer and the precast bottom plate of the composite slab, respectively. Compared with ordinary triangular truss reinforcement, the embedding effect is stronger and the overall performance of the composite slab is better.

[0018] 2. The steel plate chord single-web truss used in this utility model has a significant effect on improving the rigidity of the precast base plate, which can meet the requirement that no support is needed when pouring cast-in-place composite concrete, thereby reducing construction costs and improving construction efficiency.

[0019] 3. The lower chord steel plate and the longitudinal reinforcement are at the same height in this utility model, which avoids the transverse reinforcement passing through the height range of the single web reinforcement truss of the steel plate chord, thus saving labor and improving production efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the composite plate of this utility model;

[0021] Figure 2 This is a schematic diagram of the steel mesh structure of this utility model;

[0022] Figure 3 This is a schematic diagram of the connection between the precast base plate and the steel plate chord single-web truss of this utility model;

[0023] Figure 4 This is a schematic diagram of the steel plate chord single-web truss structure of this utility model;

[0024] In the diagram: 1. Precast base plate, 2. Steel plate chord single-web truss, 3. Longitudinal reinforcement, 4. Transverse reinforcement, 5. Top chord steel plate, 6. Bottom chord steel plate, 7. Web reinforcement. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0026] This utility model discloses a support-free precast concrete composite slab, comprising a precast base slab 1 and an internal steel mesh, and several steel plate chord single-web trusses 2 partially embedded in the precast base slab. The steel plate chord single-web truss 2 includes an upper chord steel plate 5, a lower chord steel plate 6, and web reinforcement 7 connecting the upper chord steel plate 5 and the lower chord steel plate 6. The upper chord steel plate 5 and the lower chord steel plate 6 are both made of steel, and the web reinforcement 7 is made of steel bars. The steel plate chord single-web truss 2 is connected to the precast base slab 1 by partial pre-embedding to improve the bending stiffness of the precast concrete composite slab and thus achieve the support-free function. Longitudinal reinforcement 3 and transverse reinforcement 4 are arranged in the precast base slab 1 to form a steel mesh structure.

[0027] Preferably, the steel mesh formed by the longitudinal steel bars 3 and the transverse steel bars 4 in the precast base plate 1 is connected to the lower chord steel plate 6 of the steel plate chord single web truss 2 by binding.

[0028] Preferably, the steel mesh formed by the longitudinal steel bars 3 and the transverse steel bars 4 in the precast base plate 1 is connected to the lower chord steel plate 6 of the steel plate chord single web truss 2 by welding.

[0029] Preferably, the longitudinal and transverse reinforcing bars in the precast base slab are prestressed tendons or ordinary reinforcing bars, which can be completely embedded inside the precast base slab or extend out to a certain length.

[0030] Preferably, the cross-sectional shape of the upper chord steel plate 5 and the lower chord steel plate 6 is rectangular, circular or I-shaped.

[0031] Preferably, the included angle between the web rib 7 and the upper chord steel plate 5 and the lower chord steel plate 6 is 30°-60°.

[0032] Preferably, the upper and lower edges of the precast base plate 1 are chamfered, and adjacent precast concrete composite slabs are spliced ​​together by the chamfers.

[0033] Preferably, polymer mortar is provided inside the chamfer to prevent mortar leakage at the joint.

[0034] Preferably, the surface of the precast base plate 1 is provided with a rough surface to increase the adhesion to the subsequent cast-in-place concrete layer.

[0035] Preferably, the precast concrete composite slab further includes a release agent layer disposed at the bottom of the precast base slab 1, the release agent layer being used to facilitate demolding during the production process of the precast concrete composite slab.

[0036] Example 1

[0037] This embodiment discloses a supportless precast concrete composite slab, including a precast base slab 1, two steel plate chord single-web trusses 2, a steel mesh embedded in the precast base slab 1, a rough surface, and a release agent layer.

[0038] The precast base slab 1 has a cross-sectional dimension of 1000×60mm, a length of 3700mm, and a marked span of 3900mm, and is made of C40 concrete. Its surface is roughened by mechanical chiseling to create a rough surface with a depth of 5-8mm and an average depth of 6mm, to enhance adhesion to the subsequent cast-in-place concrete layers. A layer of water-based release agent, model HT-801, is applied to the bottom with a thickness of 0.2mm using a high-pressure airless spraying process to ensure no damage to the surface of the precast base slab 1 during demolding. The reinforcing mesh consists of an upper layer of longitudinal reinforcing bars 3 and a lower layer of transverse reinforcing bars 4. The longitudinal reinforcing bars 3 are 11 strands of 5mm diameter stress-relieved spiral ribbed steel wire with a standard tensile strength of 1570N / mm². 2 The tension control stress is 0.75 × 1570 = 1177.5 N / mm². 2 The transverse reinforcement 4 is made of HRB400 grade ordinary steel bar with a diameter of 6mm and a spacing of 200mm. It is orthogonally tied to the longitudinal reinforcement 3, and the tying node spacing does not exceed 400mm.

[0039] The structural parameters of the steel plate chord single-web truss 2 are as follows:

[0040] The upper chord steel plate 5 is made of Q235B carbon structural steel with a yield strength of not less than 235 MPa and a rectangular cross-section of 50×10mm. Its length is the same as that of the precast base plate 1. The lower chord steel plate 6 is made of Q235B carbon structural steel with a yield strength of not less than 235 MPa and a rectangular cross-section of 30×4mm. Its length is the same as that of the precast base plate 1. The web reinforcement 7 is made of HRB400 grade corrugated ordinary steel bar with a diameter of 8mm, a wavelength of 200mm, and a wave height of 60mm. It is welded to the upper chord steel plate 5 at the crest and to the lower chord steel plate 6 at the trough. The welding method is arc welding, with a weld height of 4mm and a weld length of not less than 20mm.

[0041] The truss is 75mm high and consists of two sections spaced 0.5m apart. The lower chord steel plate 6 is located above the transverse reinforcement 4, at the same height as the longitudinal reinforcement 3, and 23mm from the bottom surface of the precast base slab 1. The lower chord steel plate 6 is tied to the transverse reinforcement 4, with the tying nodes spaced no more than 400mm apart.

[0042] The upper and lower edges of the precast base plate 1 are chamfered, with the upper chamfer measuring 20mm × 20mm. The chamfer is filled with polymer mortar, using M20 polymer-modified cement mortar, to prevent grout leakage when adjacent composite slabs are spliced.

[0043] The stiffness data of different types of precast slabs obtained through comparative experiments are shown in Table 1 below:

[0044] Table 1 Comparison of Stiffness of Precast Base Plates

[0045]

[0046] The specific installation process in this embodiment is as follows:

[0047] During installation, the upper chord steel plate 5 is used as a lifting point. A special lifting clamp is used to lift the slab at a distance of 0.2 times the length of the precast slab from both ends of the truss. The composite slab is then lifted into place, with adjacent slabs chamfered and aligned, and compacted with polymer mortar. A 70mm layer of concrete with a strength grade of C30 is then poured directly. Since the stiffness of the precast base slab 1 meets the requirements, the equivalent moment of inertia is 3970-3389mm. 4 No temporary supports are required within the span; after the cast-in-place concrete layer is cured to the design strength, it forms an integral load-bearing composite slab.

[0048] The above embodiments are merely preferred technical solutions of this utility model and should not be considered as limitations on this utility model. The protection scope of this utility model should be the technical solution described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the protection scope of this utility model.

Claims

1. A support-free precast concrete composite slab, characterized in that, The structure includes a precast base plate (1) and an internal steel mesh, as well as several steel plate chord single-web trusses (2) partially embedded in the precast base plate. The steel plate chord single-web truss (2) includes an upper chord steel plate (5), a lower chord steel plate (6), and web reinforcement (7) connecting the upper chord steel plate (5) and the lower chord steel plate (6). The upper chord steel plate (5) and the lower chord steel plate (6) are both made of steel, and the web reinforcement (7) is made of steel bars. The steel plate chord single-web truss (2) is connected to the precast base plate (1) by partial pre-embedding and embedding. The longitudinal reinforcement (3) and the transverse reinforcement (4) are set in the precast base plate (1) to form a steel mesh structure.

2. The support-free precast concrete composite slab according to claim 1, characterized in that, The steel mesh formed by the longitudinal steel bars (3) and transverse steel bars (4) in the precast base plate (1) is connected to the lower chord steel plate (6) of the steel plate chord single web truss (2) by binding.

3. The support-free precast concrete composite slab according to claim 1, characterized in that, The steel mesh formed by the longitudinal steel bars (3) and transverse steel bars (4) in the precast base plate (1) is connected to the lower chord steel plate (6) of the steel plate chord single web truss (2) by welding.

4. The support-free precast concrete composite slab according to claim 1, characterized in that, The longitudinal and transverse reinforcing bars in the precast base slab (1) are prestressed tendons or ordinary reinforcing bars, which can be completely embedded inside the precast base slab or extend out to a certain length.

5. The support-free precast concrete composite slab according to claim 1, characterized in that, The cross-sectional shape of the upper chord steel plate (5) and the lower chord steel plate (6) is rectangular, circular or I-shaped.

6. The support-free precast concrete composite slab according to claim 1, characterized in that, The included angle between the rib (7) and the upper chord steel plate (5) and the lower chord steel plate (6) is 30°-60°.

7. The support-free precast concrete composite slab according to claim 1, characterized in that, The precast base plate (1) has chamfers on its upper and lower edges, and adjacent precast concrete composite slabs are spliced ​​together by the chamfers.

8. A precast concrete composite slab without support according to claim 7, characterized in that, The chamfer is filled with polymer mortar to prevent mortar leakage at the joint.

9. A precast concrete composite slab without support according to claim 1, characterized in that, The surface of the precast base plate (1) is roughened to increase the adhesion to the subsequent cast-in-place concrete layer.

10. A support-free precast concrete composite slab according to claim 1, characterized in that, The precast concrete composite slab also includes a release agent layer disposed at the bottom of the precast base plate (1), the release agent layer being used to facilitate demolding during the production process of the precast concrete composite slab.

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