A truss
By using a thin steel plate bent into an upper flange and a toothed staggered structure, combined with welded steel reinforcement web members and prestressed concrete design, the problem of insufficient bending strength and stiffness of existing trusses is solved, achieving higher material utilization and increased span of composite floor slabs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU SHENGCON TECH CO LTD
- Filing Date
- 2025-08-01
- Publication Date
- 2026-07-21
AI Technical Summary
The existing steel reinforcement or steel pipe trusses have small spacing at the troughs and insufficient connection strength, resulting in low bending strength and stiffness of the trusses, easy deformation, and low material utilization. They cannot effectively improve the lateral bending strength and span of composite floor slabs and floor decking.
The upper flange is formed by bending thin steel plate to create a toothed interlaced structure. The reinforcing bar web members are connected to the upper flange by welding to enhance the texture design. The lower flange reinforcing bars are welded at the troughs of the reinforcing bar web members. Prestressed steel bars and fiber-reinforced materials are set in the concrete base slab to form a prestressed concrete composite slab.
It significantly improves the in-plane and out-of-plane stiffness and bending strength of the truss, increases material utilization, improves the lateral bending strength and span of the composite floor slab and floor decking, and ensures the reliability of the connection and the full utilization of materials.
Smart Images
Figure CN224532052U_ABST
Abstract
Description
Technical Field
[0001] This utility model specifically relates to the field of building engineering technology, and is a truss that can be widely used in the floor slabs and beams of various buildings. Background Technology
[0002] Existing technologies using trusses in composite floor slabs or truss-type floor decks primarily employ reinforced steel or steel pipe trusses. Their characteristic feature is that the upper flange is made of reinforced steel, steel pipe, channel steel, or various types of steel, with reinforced steel and steel pipe being the most widely used. However, both reinforced steel and steel pipe trusses present the following problems:
[0003] The spacing of the reinforcing bar web members at the troughs is relatively small. In traditional trusses, the spacing between two reinforcing bar web members at the troughs is approximately 80mm. Although the spacing between two reinforcing bar web members is slightly increased after using steel pipes in the literature patent (CN 119825071 A), the increase in steel content due to the use of steel pipes limits the extent of the increase in the spacing of the reinforcing bar web members. This is not conducive to improving the lateral bending strength of composite floor slabs, floor decks, and thin-bottom beams. In floor decks combined with trusses, the steel plates between the trusses are prone to deformation, posing a safety risk. In thin-bottom composite slabs combined with trusses, the concrete base slab between the trusses is prone to cracking.
[0004] The upper flange is made of steel bars, steel pipes, or structural steel. With the same amount of steel used in the same cross-section, the centroid of the upper flange section is smaller than the centroid of the lower chord of the truss, significantly reducing the truss's moment of inertia. This results in lower bending strength and stiffness, and consequently, a smaller span for the precast slabs and floor decks combined with the same truss. Furthermore, the distance from the top surface of the poured concrete slab is larger, drastically reducing the utilization rate of the upper flange within the concrete slab and hindering the full utilization of material strength. This is as described in patent (CN 119825071 A).
[0005] The connection strength between the reinforcing bar web members and the upper flange is insufficient. Since both the steel pipe and the reinforcing bar are circular cross-sections, the connection between the reinforcing bar web members and the flange is only one point, meaning the connection strength cannot guarantee the truss's load-bearing capacity. As described in the following documents: Patents (CN 214614894 U) and CN 214614890 U mention spot welding at the connection point between the steel pipe and the reinforcing bar. However, the weld contact point is very small and cannot guarantee the coordinated operation of the upper chord and the reinforcing bar web members. Patent (CN119531599A) mentions resistance spot welding between the upper chord reinforcing bars and the reinforcing bar web members in a steel truss. Utility Model Content
[0006] Therefore, this utility model proposes a truss to improve the out-of-plane strength of the truss, enhance the in-plane bending stiffness and strength of the truss, and make the connection between the steel reinforcement web members and the upper flange more reliable, while reducing the connection and processing costs. This solves and optimizes the problems in the aforementioned background technology.
[0007] To achieve the above objectives, this utility model discloses a truss, which includes:
[0008] Upper flange: formed by bending a thin steel plate with a thickness of 0.8-3mm, including a web and legs arranged on both sides of the web, the legs being below the web, the angle between the legs and the web being 90°~135°, and the length of the legs being 10~20mm;
[0009] Reinforcing bar web: It is composed of continuously bent reinforcing bars with the same inclination as the legs. The peak nodes of the reinforcing bar web are welded to the legs.
[0010] Further technical solutions are as follows:
[0011] The lower edge of the upper flange foot forms a gap at the corresponding position of the trough of the reinforcing bar web, exhibiting a serrated, staggered shape. This design allows adjacent steel plates to interlock during steel cutting, concentrating more steel on the upper flange web, resulting in superior mechanical properties with the same amount of steel used. The serrations satisfy the connection requirements with the reinforcing bar web and the force transmission requirements between the reinforcing bar web and the flange.
[0012] Furthermore, preferably, the reinforcing bar web is located on the inner or outer side of the upper flange foot.
[0013] Furthermore, as a preferred embodiment, the reinforcing bar web members are bent at the crests to form a horizontal platform.
[0014] Furthermore, as a preferred embodiment, the reinforcing bar web members bend outward at the troughs to form an outward V-shape.
[0015] The upper flange surface is provided with reinforcing grooves, which are selected from at least one of transverse corrugated ribs, longitudinal reinforcing ribs, or oblique indentations, with a groove depth of 0.2-0.8 mm. The upper flange is made of thin steel plate bent into shape, and the local yield bearing capacity of the thin steel plate can be enhanced by indentations or longitudinal and transverse ribs. After the concrete is poured, the upper flange is very close to the top of the concrete, which can withstand the tensile stress on the concrete surface and prevent cracking at the top of the concrete. The grooves or indentations on the upper flange can enhance the adhesion between the upper flange and the concrete, and make fuller use of the mechanical properties of the thin steel of the upper flange.
[0016] Thin-walled steel plates, 0.5-1.5 mm thick, are welded to the reinforcing web members at the troughs. These thin-walled steel plates, when welded together, form a truss floor deck. Compared to existing truss floor decks, this design significantly improves performance and saves on steel consumption. If the steel plate is too thin (less than 0.5 mm), the base plate will have insufficient rigidity and cannot meet local load-bearing requirements; if it is thicker than 1.5 mm, the steel consumption will be too high, making it uneconomical.
[0017] The lower flange reinforcement with a diameter of 6-12mm is welded at the trough of the web member of the steel bar, and the reinforcement is parallel to the upper flange.
[0018] Furthermore, as a preferred embodiment, the lower flange steel is double-layered, with the upper lower flange steel being reinforcing steel and the lower lower flange steel being reinforcing steel or flat steel.
[0019] Furthermore, as a preferred embodiment, the upper lower flange steel is located inside or outside the web of the reinforcing bar, and the lower lower flange steel is located inside or outside the web of the reinforcing bar, or below or above the trough.
[0020] The troughs of the reinforcing bar web members connect to the concrete or metal base slab. Since the troughs are close to the concrete bottom surface, they cannot meet the requirements for the concrete cover. Welding the reinforcing bars above the troughs increases the strength and stiffness of the truss, and the reinforcing bars can also be used as load-bearing reinforcement in the floor slab after the concrete is poured.
[0021] The reinforcing bar web members are connected to a concrete base slab at their troughs. The concrete base slab is made of C35-C60 concrete. The concrete base slab contains orthogonally distributed transverse and longitudinal reinforcing bars. The longitudinal reinforcing bars are prestressed steel bars.
[0022] The thin-flange truss is combined with a concrete base slab, and prestressed steel bars are set longitudinally in the concrete base slab to form a prestressed concrete composite slab. This can effectively give full play to the performance of the truss of this utility model, improve the stiffness and strength of the composite slab, and improve the span capacity of the composite slab. At the same time, the upper flange of the truss of this utility model can also participate in the stress of the concrete floor slab behind the composite slab.
[0023] The concrete base slab is either fiber-reinforced concrete with a thickness of 10-25mm or concrete with a thickness of 10-25mm and an internal welded wire mesh with a diameter of 2-5mm.
[0024] The thin-flange truss is combined with a thin concrete base plate, and wire mesh or fiber reinforcement is set in the concrete base plate to increase the strength of the thin concrete base plate. Together with the truss of this utility model, a thin-bottom concrete composite slab is formed, which can effectively give full play to the performance of the truss of this utility model, improve the stiffness and strength of the composite slab, and improve the span capacity of the composite slab. At the same time, the upper flange of the truss of this utility model can also participate in the stress of the concrete floor slab behind the composite slab.
[0025] The steel reinforcement web members are connected to a concrete composite beam at their troughs. The concrete composite beam contains longitudinal reinforcing bars and stirrups. The diameter of the longitudinal reinforcing bars is 12-25mm, the spacing of the stirrups is 50-250mm, and the thickness of the concrete composite beam is 80mm-150mm.
[0026] The present invention, by adopting the above structure, has the following beneficial effects compared with the existing technology:
[0027] A. The out-of-plane and in-plane stiffness of the truss are significantly improved. In this utility model device, thin-walled cold-formed steel is used as the upper flange. With the same amount of steel, the steel unfolded width is larger, the distance between the two truss legs is greater, and the upper flange is combined with the floor decking and composite slabs, increasing the out-of-plane stiffness and strength of the truss. The floor decking or composite slabs between the trusses have greater stiffness and strength, and the crack resistance is significantly improved. With the increased steel unfolded width, the lateral stability of the upper flange is better.
[0028] B. With the same amount of steel, the truss has the highest in-plane bending stiffness and strength, and the span of the members can be larger without bracing. The centroid of the thin-walled upper flange is farther from the lower chord with the same amount of steel, which increases the moment of inertia of the truss. The bending stiffness and strength of the truss are increased by about 20% compared with existing technologies, thereby increasing the span of floor decking or composite slabs.
[0029] C. After the floor slab is poured, the utilization rate of the upper flange steel increases. With the upper flange extended, the distance from the centroid of the upper flange to the top of the poured floor slab decreases, which is more conducive to the strength development of the upper flange. The extended upper flange also increases the contact area between the upper flange and the concrete, improving the bond strength between the concrete and the upper flange, thus fully utilizing the strength of the upper flange. Especially in the composite floor slab or floor decking within the span beams, the utilization of the upper flange steel is maximized, thereby reducing the amount of steel used.
[0030] D. The truss connections are more reliable, and the truss has better stress stability. The legs of the thin-walled upper flange are in full contact with the reinforcing web members, which can ensure the connection strength between the reinforcing web members and the truss, avoid the arc area caused by the bending of the reinforcing web members, and effectively utilize the strength and stiffness of the truss.
[0031] E. Truss fabrication is simpler, more energy-efficient, and less costly. The legs of the cold-bent upper flange are in full contact with the reinforcing bar web members, allowing resistance welding to be used to connect the upper flange and the reinforcing bar web members, thus saving welding materials. Compared to the welding process of the upper flange of structural steel, it is simpler, and compared to the gas shielded welding of the upper flange of steel pipe, it uses less welding materials. Attached Figure Description
[0032] Figure 1 is a schematic diagram of the upper flange structure of a truss;
[0033] Figure 2 is a schematic diagram of the upper flange structure of a truss;
[0034] Figure 3 is a schematic diagram of the upper flange structure of a truss;
[0035] Figure 4 is a schematic diagram of a truss structure;
[0036] Figure 5 is a schematic diagram of a truss structure;
[0037] Figure 6 is a schematic diagram of a truss structure;
[0038] Figure 7 This is a schematic diagram of a truss structure;
[0039] Figure 8 This is a schematic diagram of a truss structure;
[0040] Figure 9 This is a schematic diagram of a truss structure;
[0041] Figure 10 is a schematic diagram of a truss combined with a steel plate;
[0042] Figure 11 is a schematic diagram of a structure combining a truss with a concrete slab (thickness greater than 30mm);
[0043] Figure 12 This is a schematic diagram of a structure combining a truss with a concrete slab (10-25mm thick);
[0044] Figure 13 is a schematic diagram of a structure combining a truss with a concrete slab and having longitudinal steel bars and stirrups inside the slab.
[0045] Figure 14 is a schematic diagram of another angle of a truss combined with a concrete slab, with longitudinal steel bars and stirrups inside the slab.
[0046] In the diagram: 1. Upper flange; 1-1. Leg; 1-2. Web; 3. Lower flange steel; 3-1. Upper lower flange steel; 3-2. Lower lower flange steel; 4. Thin steel plate; 5. Concrete base slab; 6. Transverse reinforcement; 7. Concrete composite beam; 8. Longitudinal reinforcement; 9. Stirrups; 10. Longitudinal reinforcing bars. Detailed Implementation
[0047] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0048] Example 1: Please refer to Figures 1-5. This utility model provides a technical solution: a truss, which includes: an upper flange: formed by bending a thin steel plate with a thickness of 0.8-3mm, including a web and legs symmetrically arranged on both sides of the web, the legs being below the web, the angle between the legs and the web being 90°~135°, and the extension length of the legs being 10~20mm; a steel reinforcement web: composed of continuously bent steel bars, the inclination of which is consistent with that of the legs, and each crest node being welded to the legs.
[0049] In this embodiment, 0.8-3mm steel plates are cold-bent into upper flanges with webs and legs. The purpose is to maximize the unfolding of the same steel material, thereby improving the mechanical properties of the truss and simultaneously meeting the requirements for connection between the reinforcing web members and the legs, as well as the local stability of the upper flange steel plate. If the steel plate is too thin, resistance welding is prone to burn-through, so gas shielded welding is required. If the web width is too large, it will lead to local buckling. If the steel plate thickness is too large, the difficulty of cold bending increases, and the unfolding width of the steel material is limited, making it difficult to increase the moment of inertia of the section and thus failing to achieve the performance of this utility model. The leg length is 10-20mm, which allows the legs to meet the requirements for connection with the reinforcing web members and to enhance the out-of-plane stiffness of the upper flange. Minimizing the leg length keeps the centroid of the upper flange as high as possible, increasing the distance to the lower chord of the truss members, and bringing the centroid of the section closer to the top surface of the completed concrete. The angle between the legs and the upper flange is controlled between 90 and 135 degrees. Combined with the increased width of the upper flange, this allows for a greater distance between the lower ends of the two reinforcing web members, creating a spatial structure between the reinforcing web members, the upper flange, and the base plate. This enhances the stiffness and strength of the base plate outside the truss. However, the angle should not be too large; otherwise, the increased length of the reinforcing web members, coupled with a higher slenderness ratio, increases the internal forces in the members, leading to increased shear deformation of the truss and a decrease in its in-plane stiffness. The upper flange is cold-bent, simplifying processing, saving energy, and reducing cost. The inclination angle between the legs and the web plate is the same as that between the reinforcing web members and the web plate, ensuring full contact between them. The relationship between the reinforcing web members and the upper flange is a line-to-plane relationship, resulting in a more reliable and stable connection strength. This ensures the full utilization of the mechanical properties of the upper flange and the reinforcing web members, while also enhancing the constraint of the reinforcing web members on the upper flange.
[0050] Furthermore, a gap is formed at the lower edge of the upper flange foot at the position corresponding to the trough of the reinforcing bar web. As shown in Figures 2, 3, and 5, the steel strips can be staggered during the forming process to reduce the amount of steel used in the foot and use more steel in the web, thereby further improving the performance of the truss.
[0051] Furthermore, the upper flange surface is provided with reinforcing patterns, which are selected from at least one of transverse corrugated ribs, longitudinal reinforcing ribs, or oblique indentations. The pattern depth is 0.2-0.8 mm. For thin-walled structures, the presence of indentations or ribs can improve the out-of-plane stiffness of the plate, reduce local instability, and thus enhance the performance of the truss. Simultaneously, the indentations, ribs, or longitudinal ribs can increase the bonding performance between the upper flange and the formed concrete, allowing for more effective utilization of the mechanical properties of the upper flange under structural use conditions, and further saving steel consumption.
[0052] Example 2: Basically the same as Example 1, except that a lower flange steel bar with a diameter of 6-12mm is welded at the trough of the web of the steel bar, and this steel bar is parallel to the upper flange. See Figure 6.
[0053] In this example, when reinforcing bars are welded at the troughs of the web members to form a complete truss, it can be used for composite floor slabs with weak base plates, such as thin, unreinforced concrete slabs. It can also be used to strengthen weak base plates, such as when the steel deck of a truss floor requires a large span, and the strength and stiffness provided by the base plate alone are insufficient. In such cases, the lower flange of the reinforcing bars can be added to improve the strength and stiffness of the member. Simultaneously, the lower flange reinforcement can also serve as bottom reinforcement for the concrete, thus avoiding material waste.
[0054] Example 3: It is basically the same as Example 1, except that the trough of the reinforcing bar web members is connected to the thin steel plate, as shown in Figure 7, to form a truss floor deck. This fully utilizes the in-plane and out-of-plane stiffness of the thin flange truss. Compared with the traditional steel truss floor deck, the number of thin flange trusses is less than the number of steel trusses on the same width floor deck, and the mechanical properties are better.
[0055] Example 4: It is basically the same as Example 1, except that the trough of the reinforcing bar web is connected to the concrete base slab to form a concrete composite slab.
[0056] Furthermore, the longitudinal reinforcement of the concrete composite slab is prestressed, as shown in Figure 8. The thickness of the bottom slab is 30-50mm. The stiffness of the bottom slab in the direction outside the truss is relatively weak. Using this truss can effectively enhance the strength of the concrete bottom slab outside the truss and reduce cracking of the bottom slab.
[0057] Furthermore, the concrete base slab is made of 10-25mm thick fiber-reinforced slab, as shown in Figure 9. The base slab is weaker in strength and stiffness in the vertical direction of the truss. Using this truss can effectively enhance the strength of the concrete base slab outside the truss and reduce cracking of the base slab.
[0058] Example 5: Basically the same as Example 1, except that the troughs of the reinforcing bar web members are connected to a concrete composite beam. The concrete composite beam is equipped with longitudinal reinforcing bars and stirrups. The diameter of the longitudinal bars is 12~25mm, the spacing of the stirrups is 50~250mm, and the thickness of the concrete composite beam is 80mm~150mm. Refer to Figures 10 and 11.
[0059] In this example, the truss of this utility model is combined with a concrete base slab and stirrups to form a thin-bottomed concrete composite beam. The truss strengthens the strength and rigidity of the thin-bottomed concrete slab. Since concrete composite beams are generally long and subject to significant stress, the stirrups need to be tied before the truss is installed, and the truss must also meet certain rigidity requirements. The truss of this utility model perfectly meets these conditions. Compared to traditional trusses, the truss of this utility model is lighter per unit length and has higher strength, making its installation simpler and more convenient.
[0060] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A truss, characterized in that, include: The upper flange (1) is formed by bending a thin steel plate with a thickness of 0.8-3mm, and includes a web (1-2) and legs (1-1) arranged on both sides of the web (1-2). The legs (1-1) are below the web (1-2), and the angle between the legs (1-1) and the web (1-2) is 90°~135°. The length of the legs (1-1) is 10~20mm. The reinforcing bar web (2) is composed of continuously bent reinforcing bars, and its inclination is consistent with that of the foot (1-1). The crests of the reinforcing bar web (2) are welded to the foot (1-1).
2. A truss according to claim 1, characterized in that: The lower edge of the leg (1-1) forms a gap at the position corresponding to the trough of the reinforcing bar web.
3. A truss according to claim 1, characterized in that: The reinforcing bar web member (2) is located inside or outside the upper flange leg (1-1).
4. A truss according to claim 1, characterized in that: The upper flange (1) surface is provided with reinforcing textures, which are at least one of transverse corrugated ribs, longitudinal reinforcing ribs, or oblique indentations.
5. A truss according to claim 1, characterized in that: The reinforcing bar web (2) has a horizontal platform bent at the crest.
6. A truss according to claim 1, characterized in that: The steel bar web member (2) bends outward at the trough to form an outward V-shape.
7. A truss according to claim 1, characterized in that: Thin steel plates (4) are welded at the trough nodes of the reinforcing bar web members (2).
8. A truss according to claim 1, characterized in that: The lower flange steel (3) with a diameter of 6-12mm is welded at the trough of the web member (2) of the steel bar, and the lower flange steel (3) is parallel to the upper flange (1).
9. A truss according to claim 8, characterized in that: The lower flange steel (3) is double-layered, with the upper lower flange steel (3-1) being a reinforcing bar and the lower lower flange steel (3-2) being a reinforcing bar or flat steel.
10. A truss according to claim 9, characterized in that: The upper lower flange steel (3-1) is inside or outside the reinforcing bar web (2), and the lower lower flange steel (3-2) is inside or outside the reinforcing bar web (2) or below or above the trough.
11. A truss according to claim 1, characterized in that: The trough of the steel reinforcement web member (2) is connected to a concrete base plate (5).
12. A truss according to claim 11, characterized in that: The concrete base slab (5) is made of C35-C60 concrete, and the concrete base slab (5) is provided with orthogonally distributed transverse steel bars (6) and longitudinal steel bars (8).
13. A truss according to claim 12, characterized in that: The longitudinal reinforcement (8) is a prestressed reinforcement.
14. A truss according to claim 11, characterized in that: The concrete base plate (5) is fiber-reinforced concrete with a thickness of 10~25mm or concrete with a thickness of 10~25mm and a welded wire mesh with a diameter of 2~5mm inside.
15. A truss according to claim 1, characterized in that: The trough of the steel bar web (2) is connected to a concrete composite beam (7). The concrete composite beam (7) is equipped with longitudinal reinforcing bars (10) and stirrups (9). The diameter of the longitudinal reinforcing bars is 12-25mm, the spacing of the stirrups (9) is 50-250mm, and the thickness of the concrete composite beam (7) is 80mm~150mm.