Steel pipe truss for laminated slab and floor system

Abstract

The steel pipe truss comprises a concrete prefabricated bottom plate (1) and an upper chord steel pipe (2), the left side and the right side of the upper chord steel pipe (2) are each in an arc shape, the upper ends of the arcs on the left side and the right side are connected to form an upper straight line section, the lower ends of the arcs on the left side and the right side are connected to form a lower straight line section, and the lengths of the upper straight line section and the lower straight line section are both 15-80 mm; the prefabricated concrete bottom plate further comprises a web member (3), the web member (3) is formed by continuously bending a hollow steel pipe into a wave shape, the wave crest of the wave-shaped web member (3) is welded to the bottom face of the lower linear section of the upper chord steel pipe (2), and the wave trough part of the wave-shaped web member (3) is buried in the prefabricated concrete bottom plate (1). The hollow web member is creatively welded with the straight section at the bottom of the upper chord steel pipe, and the thickness of the steel plate at the lower straight section of the upper chord steel pipe is increased, so that the defect can be better avoided, and the welding strength is ensured.

Description

A steel pipe truss and floor system for composite slabs Technical Fields

[0001] This utility model relates to a building truss, specifically a composite slab steel pipe truss and its floor slab. Background Technology:

[0002] Trusses are a common building component. Currently, trusses used in construction consist of a top chord steel bar connected to two bottom chord steel bars by web members, welded together as a whole. The welds between the web members and the top and bottom chord steel bars are located at the bends at the ends of the web members. Because the bends of the web members have poor stiffness, they are prone to deformation under stress, making it difficult to effectively transfer compressive and tensile forces between the top and bottom chord steel bars, thus affecting the overall stiffness of the truss. To improve truss stiffness, those skilled in the art have proposed replacing the top chord steel bar with a circular steel tube. This structure enhances the strength of the truss at the top chord position, but the deformation problem of the web members remains unresolved, failing to fundamentally improve the overall rigidity of the truss. Invention content and utility model content:

[0003] The technical problem to be solved by this utility model is that, in the prior art, replacing the top chord steel bars with steel pipes enhances the strength of the truss, but still cannot overcome the problem of web member deformation, and thus cannot fundamentally improve the overall rigidity of the truss.

[0004] The technical solution adopted by this utility model to solve its technical problem is to propose a steel pipe truss for composite slabs, which includes a precast concrete base plate (1) and an upper chord steel pipe (2). The upper chord steel pipe (2) has arc-shaped left and right sides. The upper ends of the arcs on the left and right sides are connected to form an upper straight line segment, and the lower ends of the arcs on the left and right sides are connected to form a lower straight line segment. The length of the upper and lower straight lines is 15mm-80mm. It also includes a web member (3). The web member (3) is formed by continuously bending a hollow steel pipe to form a wave shape. The crest of the wave-shaped web member (3) is welded to the bottom surface of the lower straight line segment of the upper chord steel pipe (2), and the trough of the wave-shaped web member (3) is embedded in the precast concrete base plate (1).

[0005] As a further preferred option, cast-in-place reinforced concrete composite layer (4) is used, wherein the cast-in-place reinforced concrete composite layer is poured on the steel pipe truss and covers the steel pipe truss to form a composite slab.

[0006] Further preferred, the thickness of the steel plate of the lower straight section (21) and / or the upper straight section (22) of the upper chord steel pipe (2) is 1 to 4 times the thickness of the steel plate of the rest.

[0007] As a further preferred embodiment, the thickness of the steel plate of the lower straight section (21) and / or the upper straight section (22) of the upper chord steel pipe (2) is 1.5 to 2 times the thickness of the steel plate of the rest of the pipe.

[0008] As a further preferred option, the lower straight section, the upper straight section, and the arc-shaped steel pipes (23) on the left and right sides of the upper chord steel pipe (2) are integrally hot-rolled and formed, or they can be welded into a whole.

[0009] As a further preferred option, a support rib (24) or a support body or a support block (25) is provided between the upper straight section and the lower straight section of the upper chord steel pipe (2).

[0010] As a further preferred option, the upper chord steel pipe (2) or the web member (3) is filled with high-strength grout (26).

[0011] As a further preferred option, the diameter of the wavy web member (3) is 8mm-25mm; the plane on which the wavy web member (3) is located is perpendicular to the plane on which the lower straight section of the upper chord steel pipe (2) is located.

[0012] Further preferred, multiple filler weight-reducing bodies are embedded in the precast base plate or the multiple filler weight-reducing bodies are placed on the precast base plate at the construction site or suspended on the precast concrete base plate (1) by means of outriggers; the filler weight-reducing body can be a solid structure or a hollow structure, can be a foam product or a plastic product or a hollow steel mesh; the center points of the filler weight-reducing body are connected to form a mesh.

[0013] Further, as a preferred embodiment, the composite slab steel pipe truss also includes beams, walls or columns supporting the precast concrete base slab (1) component.

[0014] The beneficial effects of this utility model are:

[0015] 1. Currently, the industry uses round steel pipes as the top chord to bear pressure. However, in reality, large-span floor slabs require larger spans without bracing, necessitating a larger diameter top chord to withstand the pressure. Since the diameter of a round steel pipe increases proportionally with its width and height, the gap between the bottom of the pipe and the precast concrete slab becomes smaller, making pipeline passage difficult. This invention uses a top chord with a constant vertical height but expandable horizontal width. This increases the outer volume of the top chord, allowing for the injection of more high-strength grout. This significantly increases the load-bearing capacity (compression, tension, and stiffness). Simultaneously, the larger gap between the pipe and the precast base slab facilitates the passage of water and electricity pipelines beneath the pipe, simplifying construction and improving efficiency.

[0016] 2. This utility model adopts a single continuous wavy hollow web member arranged perpendicularly to the plane of the straight section of the upper chord steel pipe. Compared with the traditional method of arranging two web members with an outward V-shape on the side of the upper chord steel pipe, this arrangement results in clearer, more direct, and more efficient force distribution, while reducing the number of web members to one and saving more steel.

[0017] 3. When using a circular steel pipe with a uniform wall thickness for the upper chord, welding two outward-facing web members to the side of the upper chord can easily lead to weld penetration, causing damage and affecting weld strength. This invention creatively employs a hollow web member welded to the bottom straight section of the upper chord, and also thickens the steel plate of the lower straight section of the upper chord, thus better avoiding this defect and ensuring weld strength. Furthermore, because the bottom of the upper chord is designed as a straight section, there is no need to adapt to an arc-shaped welding surface when welding to the web member, saving welding materials and labor. The operation is also simpler, requiring no strict positioning, and is less prone to misalignment or tipping. At construction sites, the disorderly stacking of building materials such as reinforcing bars can also easily lead to damage to the upper straight section of the upper chord, often necessitating the use of thicker steel plates.

[0018] 4. In order to further reduce the amount of steel used in the upper chord steel pipe and improve the vertical compressive strength, some reinforcing parts or reinforcing blocks can be installed at the openings on both sides of the steel pipe.

[0019] 5. To facilitate the production of the upper chord steel pipe and support its shape, a long strip of iron sheet can be laid flat on the mold table. A support body of the same shape as the final steel pipe can be placed along the length of the long strip of iron sheet. The iron sheet can be rolled along the support body to form the final required steel pipe shape. Then, the longitudinal joints can be welded into a whole.

[0020] The steel pipe truss composite board (Support Free Board), abbreviated as SFB, in this patent is an upgraded version of PK board and PH board. Attached Figure Description

[0021] Figure 1 is a partial plan view of the steel pipe truss composite slab floor;

[0022] Figure 2 is a top view of the steel pipe truss composite plate;

[0023] Figure 3 is a schematic cross-sectional view of the steel pipe truss composite plate 1-1;

[0024] Figure 4 is a schematic cross-sectional view of the steel pipe truss composite plate 2-2;

[0025] Figure 5 is a schematic diagram of a steel pipe truss (I);

[0026] Figure 6 is a schematic diagram of the steel pipe truss (II);

[0027] Figure 7 is a schematic diagram of the steel pipe truss (III);

[0028] Figure 8 is a perspective view of the steel pipe truss. Detailed Implementation

[0029] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] A steel pipe truss for composite slabs includes a precast concrete base slab 1 and an upper chord steel pipe 2. The upper chord steel pipe has arc-shaped left and right sides. The upper ends of the arcs on the left and right sides are connected to form an upper straight segment, and the lower ends of the arcs on the left and right sides are connected to form a lower straight segment. The length of the upper and lower straight segments is 15-80mm.

[0032] The precast concrete base slab is made of C30 concrete, with a thickness of 60mm, a width of 1200mm, and a length of 3600mm. A steel mesh is installed inside the precast concrete base slab, consisting of 8mm diameter steel bars arranged at 200mm x 200mm intervals to enhance the structural strength of the precast concrete base slab.

[0033] The upper chord steel pipe is elliptical in shape, consisting of a lower straight section, left and right circular arcs, and an upper straight section. The lower straight section is 15-80mm long, and the upper straight section is the same length as the lower straight section. Both left and right sides are circular arcs with a radius of 40mm. The upper chord steel pipe is made of Q345 steel, which has good strength and toughness.

[0034] The composite slab steel pipe truss also includes web members 3, which are formed by continuously bending a hollow steel pipe into a wavy shape. The wavy web members have a diameter of 8mm-25mm, a wall thickness of 1mm, and are made of Q235 steel. The crests of the wavy web members are welded to the bottom surface of the straight section below the upper chord steel pipe, and the troughs of the wavy web members are embedded in the precast concrete base slab. The wavelength of the wavy web members is 300mm, and the wave height is 150mm. The entire web member is continuously bent along the length of the upper chord steel pipe to form multiple crests and troughs.

[0035] The crests of the corrugated web members are firmly connected to the bottom surface of the lower straight section of the upper chord steel pipe by welding. The weld is a circumferential weld with a thickness of 4mm. The troughs of the corrugated web members are embedded in the precast concrete base slab to a depth of approximately 40mm to ensure sufficient anchorage length between the web members and the precast concrete base slab.

[0036] The thickness of the steel plate in the lower straight section of the upper chord steel pipe is 1-4 times the thickness of the steel plate in the rest of the upper chord steel pipe. That is, if the steel plate thickness of the lower straight section is 8mm, the steel plate thickness of the rest of the upper chord steel pipe is 2-8mm. This design gives the lower straight section of the upper chord steel pipe a higher load-bearing capacity, enabling it to withstand greater welding stress and structural loads.

[0037] The thickness of the steel plate in the straight section of the upper chord steel pipe is 1-4 times that of the rest of the upper chord steel pipe. This design gives the straight section of the upper chord steel pipe a higher load-bearing capacity, enabling it to withstand the pressure transmitted from the superstructure.

[0038] In another embodiment, the thickness of the steel plate for the upper and lower straight segments is 1.5 to 2 times the thickness of the steel plate for the rest of the upper chord steel pipe.

[0039] The lower straight section, upper straight section, and the arc-shaped steel pipes on both sides of the upper chord are integrally hot-rolled to form a single structure, avoiding structural weaknesses that may arise from welded joints. The integrally hot-rolled upper chord steel pipe has better integrity and load-bearing capacity.

[0040] Supporting ribs 24 are installed between the upper and lower straight sections of the upper chord steel pipe. The supporting ribs are made of solid steel bars with a diameter of 10mm and are evenly arranged at a spacing of 300mm. The two ends of the supporting ribs are welded to the upper and lower straight sections respectively to form a stable triangular support structure, which enhances the overall rigidity and stability of the upper chord steel pipe.

[0041] In another embodiment, a support block 25 is provided between the upper and lower straight sections of the upper chord steel pipe. The support block is made of solid steel, with dimensions of 30mm × 30mm × 30mm, and is evenly arranged at 200mm intervals. The upper and lower surfaces of the support block are welded or abutted to the upper and lower straight sections respectively, forming a stable support structure and enhancing the overall rigidity and stability of the upper chord steel pipe.

[0042] In another embodiment, to facilitate the fabrication of the upper chord steel pipe and its support and shaping, a long strip of sheet metal can be laid flat on the mold table, and a support body of the same shape as the final steel pipe can be placed along the length of the long strip of sheet metal. The sheet metal is rolled along the support body into the final required steel pipe shape, and then the longitudinal joint is welded into a whole.

[0043] The upper chord steel pipe is filled with high-strength grout 26, which has a compressive strength of 60MPa, good fluidity, and no shrinkage. The high-strength grout is injected through the grouting holes reserved in the upper chord steel pipe, completely filling the internal space of the upper chord steel pipe, thereby enhancing the rigidity and load-bearing capacity of the upper chord steel pipe.

[0044] The corrugated web members are also filled with high-strength grout, which enhances their rigidity and load-bearing capacity. The high-strength grout inside the web members is the same material as that inside the upper chord steel pipe, ensuring consistency in overall performance.

[0045] The wavy web members have a diameter of 16mm, and the plane containing the wavy web members is perpendicular to the plane containing the straight section of the upper chord steel pipe. This arrangement allows the web members to effectively transfer shear force, improving the stability and load-bearing capacity of the entire truss structure.

[0046] The composite slab steel pipe truss also includes multiple infill weight-reducing elements, which are embedded and integrated into the precast base slab. The infill weight-reducing elements are made of polystyrene foam material with a density of 20 kg / m³. 3 The structure is a cube with a side length of 200mm. The center points of the infill weight-reducing elements are connected in a mesh pattern, with a spacing of 400mm × 400mm. The infill weight-reducing elements reduce the self-weight of the composite slab while maintaining sufficient structural strength.

[0047] The composite slab steel pipe truss also includes a cast-in-place reinforced concrete composite layer 4. This layer of concrete is poured on-site onto the steel pipe truss and covers the top chord steel pipes to form the composite slab. The cast-in-place composite layer uses C30 concrete, is 100mm thick, and is internally reinforced with a two-way steel mesh with 10mm diameter bars spaced 200mm x 200mm apart. The cast-in-place composite layer, together with the precast base slab and steel pipe truss, forms an integral structure, significantly improving the overall integrity and load-bearing capacity of the composite slab.

[0048] Example 2

[0049] A floor slab includes the steel pipe truss for composite slabs as described in Embodiment 1, and also includes beams, walls, or columns supporting the precast concrete base slab components.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A steel pipe truss for composite slabs, characterized in that: It includes a precast concrete base plate (1) and an upper chord steel pipe (2). The upper chord steel pipe (2) has arc-shaped left and right sides. The upper ends of the arcs on the left and right sides are connected to form an upper straight line segment, and the lower ends of the arcs on the left and right sides are connected to form a lower straight line segment. The length of the upper and lower straight lines is 15mm-80mm. It also includes a web member (3). The web member (3) is formed by continuously bending a hollow steel pipe to form a wave shape. The crest of the wave-shaped web member (3) is welded to the bottom surface of the lower straight line segment of the upper chord steel pipe (2), and the trough of the wave-shaped web member (3) is embedded in the precast concrete base plate (1).

2. The steel pipe truss for composite slabs according to claim 1, characterized in that: It also includes cast-in-place composite reinforced concrete (4), which is cast on-site onto the steel pipe truss and covers the upper chord steel pipe to form a composite slab.

3. The steel pipe truss for composite slabs according to claim 1, characterized in that: The thickness of the steel plate of the lower straight section (21) or / and the upper straight section (22) of the upper chord steel pipe (2) is 1 to 4 times the thickness of the steel plate of the rest of the upper chord steel pipe (2).

4. The steel pipe truss for composite slabs according to claim 1, characterized in that: The thickness of the steel plate of the lower straight section (21) or / and the upper straight section (22) of the upper chord steel pipe (2) is 1.5 to 2 times the thickness of the steel plate of the rest of the upper chord steel pipe (2).

5. The steel pipe truss for composite slabs according to claim 1, characterized in that: The lower straight section, the upper straight section, and the arc-shaped steel pipes (23) on the left and right sides of the upper chord steel pipe (2) are hot-rolled or welded into a whole.

6. The steel pipe truss for composite slabs according to claim 1, characterized in that: A support bar (24) or support body or support block (25) is set between the upper straight section and the lower straight section of the upper chord steel pipe (2).

7. The steel pipe truss for composite slabs according to claim 1, characterized in that: The upper chord steel pipe (2) or the web member (3) is filled with high-strength grout (26).

8. The steel pipe truss for composite slabs according to claim 1, characterized in that: The diameter of the wavy web member (3) is 8mm-25mm; the plane where the wavy web member (3) is located is perpendicular to the plane where the straight section of the upper chord steel pipe (2) is located.

9. The steel pipe truss for composite slabs according to claim 1, characterized in that: Multiple filler weight-reducing bodies are embedded in the precast base plate or the multiple filler weight-reducing bodies are placed on the precast base plate at the construction site or suspended on the precast concrete base plate (1) by means of support legs; the filler weight-reducing body is a solid structure or a hollow structure or a foam product or a plastic product or a hollow steel mesh; the center points of the filler weight-reducing body are connected to form a mesh.

10. A floor slab, characterized in that: The composite slab steel pipe truss as described in any one of claims 1-9 further includes beams, walls or columns supporting the precast concrete base slab (1) component.

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