Truss-rib-free laminated slab and string truss supporting device thereof

Abstract

The invention relates to a truss-rib-free laminated slab and a string truss supporting device thereof, and belongs to the technical field of building structure engineering.The laminated slab comprises a prefabricated bottom plate, Y-shaped shear keys, concrete ribbed beams and ribbed bolt sleeves, traditional truss steel bars are omitted, innovative construction of the Y-shaped shear keys and the ribbed bolt sleeves is adopted, the steel consumption is remarkably reduced, and the cost is reduced. And meanwhile, pre-arching control over the prefabricated bottom plate is achieved through the string truss supporting device, and the construction efficiency and the environmental protection performance are improved. The device is designed to be three-point supporting or four-point supporting according to the span of the prefabricated bottom plate, is rapidly assembled through bolts and can be repeatedly used, and the construction cost is reduced. On the premise that the bearing performance of the structure is guaranteed, steel is saved by about 20%, the dead weight of the structure is reduced, the construction efficiency is improved, and green construction and sustainable development are achieved.

Description

Technical Field

[0001] This invention relates to the field of building structure engineering technology, and in particular to a trussless composite slab and its tensioned truss support device. Background Technology

[0002] With the accelerated advancement of my country's construction industrialization process, prefabricated buildings, with their significant advantages such as high construction efficiency, controllable quality, and environmental friendliness, have become an important direction for the transformation and upgrading of the construction industry. As a crucial load-bearing component of prefabricated buildings, the optimized design of floor slab structures directly affects the overall performance and economy of the building. Currently, reinforced concrete composite slabs are one of the most widely used forms of prefabricated floor slabs. They are mainly composed of a precast base slab, truss reinforcement, and cast-in-place concrete layers. The truss reinforcement includes top chord reinforcement, bottom chord reinforcement, and web reinforcement, which are connected by spot welding to form a spatial truss structure.

[0003] However, traditional reinforced concrete composite slabs have significant technical drawbacks in practical engineering applications. First, the truss reinforcement accounts for approximately 25% of the total steel used in the slab. This portion of steel is often not fully utilized in design calculations, resulting in significant material waste. Furthermore, to meet stiffness requirements during construction, the precast base slab thickness typically needs to be over 60mm, further increasing concrete usage and structural weight. Second, the top chord reinforcement of the truss is usually 8-12mm in diameter, making it prone to buckling instability under mid-span compression. The web reinforcement primarily serves as support for the top chord, contributing little to the shear resistance of the composite surface, resulting in low strength utilization and poor overall load-bearing performance. Third, traditional composite slabs cannot achieve prestressed camber, leading to premature stress on the reinforcement in the precast slab and stress lag in the later-cast slab, affecting the overall load-bearing performance of the composite slab. Furthermore, traditional support systems require the erection of full-span scaffolding, resulting in large material consumption, long erection periods, and significant dismantling workload. Limited by the exposed height of the truss reinforcement and its complex structure, hoisting and positioning are difficult, often necessitating the use of specialized lifting equipment. On-site stirrups are also required to support the upper steel mesh, leading to low construction efficiency. Simultaneously, the large amount of truss reinforcement and full-span scaffolding generates substantial waste after use. The support system also suffers from low standardization, hindering component reuse and resulting in insufficient environmental performance.

[0004] To address the aforementioned technical challenges, there is an urgent need to develop a new type of composite slab structure. This structure eliminates the need for traditional truss reinforcement and employs more effective shear-resistant connecting components and a detachable support system. It must ensure the shear resistance of the composite surface and the overall load-bearing capacity of the structure, while also achieving pre-camber control of the precast base slab. Simultaneously, it should significantly reduce steel consumption, improve construction efficiency, and meet the requirements for the green, efficient, and economical development of prefabricated buildings. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a truss-free composite slab and its tensioned truss support device. By eliminating the traditional truss reinforcement and adopting an innovative structure of Y-shaped shear keys and ribbed bolt sleeves, combined with a detachable tensioned truss support device, the shear resistance of the composite surface is effectively guaranteed and the pre-camber of the precast base plate is precisely controlled, thereby solving the technical problems of large steel consumption, low construction efficiency and poor environmental performance of traditional composite slabs.

[0006] To achieve the above objectives, the present invention provides a trussless composite slab and its tensioned truss support device to solve the problems of material waste and low construction efficiency of traditional reinforced concrete composite slabs. The slab includes a precast base slab, a Y-shaped shear key, concrete rib beams, and ribbed bolt sleeves. The upper horizontal surface of the precast base slab is the surface, and the lower horizontal surface is the bottom surface.

[0007] The precast base slab has a built-in bidirectional reinforcing steel mesh.

[0008] The Y-shaped shear key is embedded in the precast base plate, with its lower part anchored in the precast base plate and its upper part extending out of the surface of the precast base plate;

[0009] The concrete rib beam and the precast base plate are integrally cast, and no steel reinforcement is set inside the concrete rib beam;

[0010] The ribbed bolt sleeve is arranged inside the precast base plate. The ribbed bolt sleeve penetrates the precast base plate along its thickness direction and is located within the area of ​​the concrete rib beam. The lower end of the ribbed bolt sleeve is flush with the bottom surface of the precast base plate, and the upper end extends beyond the top surface of the concrete rib beam.

[0011] Furthermore, it has a post-cast layer with a steel mesh on it. The structure between the steel mesh and the outer surface of the concrete is a protective layer. The Y-shaped shear key is formed by bending and welding steel bars. The position of the upper support point of the Y-shaped shear key matches the height of the upper steel mesh and the thickness of the protective layer.

[0012] Furthermore, the length direction of the concrete rib beam is consistent with the long side direction of the precast base plate, the long side of the concrete rib beam is parallel to the long side of the precast base plate, and the length of the concrete rib beam exceeds 3 / 4 of the span of the precast base plate; there are at least two concrete rib beams and they are parallel to each other.

[0013] Furthermore, the ribbed bolt sleeve has a continuous thread inside and four stiffening ribs on the outside. The upper end of the ribbed bolt sleeve extends 10-20mm beyond the top surface of the concrete rib beam. Both the upper and lower ends of the ribbed bolt sleeve can be used to anchor bolts.

[0014] Furthermore, the precast base plate is made of C30-C50 concrete with a thickness of 40-60mm.

[0015] Furthermore, the Y-shaped shear keys are made of HRB400 grade steel bars with a diameter of not less than 15mm, a height of 80-100mm, and are arranged at intervals of 400-600mm.

[0016] Furthermore, the tensioned truss support device formed by the trussless composite slab as described in any of the preceding claims, wherein the tensioned truss support device adopted according to the span of the trussless composite slab includes:

[0017] The cable-stayed truss support device, consisting of a turnbuckle, hollow compression bar, and triangular connecting plate, adopts a three-point support structure or a four-point support structure depending on the span of the precast base plate.

[0018] When the span of the precast base plate is less than or equal to 4m, the three-point support includes two turnbuckles, a hollow pressure bar and a triangular connecting plate;

[0019] The triangular connecting plate has three connection points. The hollow compression bar is perpendicular to the trussless composite plate. One end of the hollow compression bar is connected to the bottom end of the trussless composite plate, and the other end of the hollow compression bar is fixed to the connection point of the triangular connecting plate.

[0020] The two ends of the turnbuckle are respectively connected to another connection point of the triangular connecting plate and the bottom end of the composite slab without truss reinforcement; the two turnbuckles are symmetrically and obliquely arranged on both sides of the span direction of the precast base slab;

[0021] When the span of the precast base slab is greater than 4m, the four-point support includes three turnbuckles, two hollow compression members, and two triangular connecting plates; one turnbuckle is arranged horizontally at the mid-span, and the two turnbuckles on both sides are arranged obliquely and symmetrically; the two hollow compression members are vertically positioned directly below the ribbed bolt sleeve at 1 / 3 span of the trussless composite slab; the two triangular connecting plates are located at 1 / 3 span of the trussless composite slab to connect the hollow compression members and the turnbuckles.

[0022] Furthermore, the basket screw includes an adjusting rod and a pull rod, with the adjusting rod located in the middle of the pull rod, and its length adjusted by rotation.

[0023] Furthermore, bolt holes are provided at both ends of the hollow pressure bar, and the hollow pressure bar is connected to the lifting eye bolt and the triangular connecting plate by bolts. The slenderness ratio of the hollow pressure bar is controlled to be below 80.

[0024] Furthermore, in one construction method, the tensioned truss support device described in any of the preceding claims is used. During the prefabrication stage, Y-shaped shear keys and ribbed bolt sleeves are pre-embedded. During hoisting, the lifting ring bolts are anchored through the ribbed bolt sleeves and connected to the lifting hook. During construction, the tensioned truss support device is adjusted on-site to arch the prefabricated base plate. After construction is completed, the tensioned truss support device is removed and reused.

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0026] (1) This invention eliminates the traditional truss reinforcement and adopts reinforced concrete ribs without reinforcement and optimized Y-shaped shear keys, which significantly reduces steel consumption and saves about 20% of steel. The thickness of the precast base plate is reduced from the traditional 60mm to 40-60mm, which reduces the self-weight of the structure and reduces the cost of the foundation. Traditional full-span scaffolding requires a large number of steel pipes, while the tensioned truss support of this invention adopts a self-balancing design and standardized connectors, which are suitable for a variety of working scenarios. The number of components is small, saving materials and transportation costs.

[0027] (2) In this invention, the tensioned truss support device adopts bolt quick assembly and has self-balancing characteristics, eliminating the need for full-span scaffolding and greatly shortening the floor support installation time; the tensioned truss support device adopts standardized connectors and adapts to various spans through turnbuckle extension and retraction, shortening the support device selection time; the Y-shaped shear key also serves as upper-layer steel reinforcement support, eliminating the need for traditional stirrups and reducing the amount of on-site steel reinforcement binding work.

[0028] (3) The present invention uses turnbuckles to precisely adjust the camber of the precast base plate, offset the deformation of the cast-in-place layer under load, and ensure the flatness of the floor slab; the Y-shaped shear key and the ribbed bolt sleeve work together to improve the shear bearing capacity of the composite surface; the upper chord reinforcement of the slender truss is eliminated to avoid the risk of instability under pressure during the construction stage and improve the structural safety factor.

[0029] (4) The detachable components of the tensioned truss support device of the present invention can be reused multiple times, which greatly reduces construction waste; the truss reinforcement structure is eliminated, saving about 20% of steel and reducing carbon emissions; the support system adopts standardized components, which can be recycled after being scrapped, realizing resource recycling.

[0030] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the trussless composite bottom plate provided by the present invention;

[0032] Figure 2 This is a schematic diagram of the three-point support system of the tensioned truss support device provided by the present invention;

[0033] Figure 3 This is a schematic diagram of the four-point support system of the tensioned truss support device provided by the present invention;

[0034] Figure 4 This is a schematic diagram of the Y-type anti-shear key provided by the present invention;

[0035] Figure 5 This is a schematic diagram of the ribbed bolt sleeve provided by the present invention;

[0036] Figure 6 This is a schematic diagram of the connection node of the tensioned truss support device provided by the present invention.

[0037] Labeling Explanation: 1. Precast base plate; 2. Y-shaped shear key; 3. Concrete ribbed beam; 4. Ribbed bolt sleeve; 5. Lifting eye bolt; 6. Tensioned truss support device; 61. Turnbuckle; 62. Hollow compression member; 63. Triangular connecting plate. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0039] In the description of this invention, it should be understood that the terms "center," "axial," "lateral," "upper," "lower," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0040] In the description of the invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] like Figures 1-6 As shown, the present invention provides a trussless composite slab, including a precast base plate 1, a Y-shaped shear key 2, a concrete rib beam 3, and a ribbed bolt sleeve 4;

[0042] The precast base slab 1 has a built-in bidirectional reinforcing steel mesh;

[0043] Y-shaped shear key 2 is embedded in the precast base plate 1, with the lower part anchored in the precast base plate 1 and the upper part extending out of the surface of the precast base plate 1;

[0044] The concrete rib beam 3 is integrally cast with the precast base plate 1, and no steel reinforcement is installed inside the concrete rib beam 3.

[0045] The ribbed bolt sleeve 4 is embedded in the precast base plate 1. The ribbed bolt sleeve 4 penetrates the precast base plate 1 in the thickness direction and is located in the area of ​​the concrete rib beam 3. The lower end of the ribbed bolt sleeve 4 is flush with the bottom surface of the precast base plate 1, and the upper end extends beyond the top surface of the concrete rib beam 3.

[0046] Furthermore, Y-type shear bond 2 (such as Figure 4 (As shown) It is formed by bending and welding steel bars, and cross-shaped anchor bars are welded to the bottom to enhance pull-out resistance. The upper support of the Y-shaped shear key 2 is matched with the height of the upper steel mesh and the thickness of the protective layer.

[0047] Furthermore, the direction of the concrete rib beam 3 is along the long side of the precast base slab 1, and the length of the concrete rib beam 3 exceeds 3 / 4 of the span of the precast base slab 1. Its height is generally more than 20mm less than the thickness of the post-cast layer.

[0048] Furthermore, the ribbed bolt sleeve 4 (such as...) Figure 5 (As shown) It is made of alloy steel, with a continuous internal thread and an inner diameter of 20-30mm, and four stiffening ribs on the outside. The upper end of the ribbed bolt sleeve 4 extends 10-20mm beyond the top surface of the concrete rib beam 3, and bolts can be anchored at both its upper and lower ends.

[0049] Furthermore, the precast base slab 1 is made of C30-C50 fine aggregate concrete with a thickness of 40-60mm and a steel reinforcement protective layer thickness of 15mm.

[0050] Furthermore, the Y-shaped shear key 2 is made of HRB400 grade steel bars with a diameter of not less than 15mm, a height of 80-100mm, and is arranged at intervals of 400-600mm.

[0051] As one embodiment, the present invention also provides a tensioned truss support device, including a turnbuckle 61, a hollow compression member 62, and a triangular connecting plate 63. The tensioned truss support device is designed as a three-point or four-point support depending on the span of the precast base slab.

[0052] When the span of the precast base slab is less than or equal to 4m, three-point support is used (e.g. Figure 2 As shown, it consists of two turnbuckles 61, a hollow pressure bar 62, and a triangular connecting plate 63.

[0053] When the span of the precast base slab is greater than 4m, four-point support is used (e.g. Figure 3 As shown, it consists of three basket screws 61, two hollow pressure rods 62 and two triangular connecting plates 63.

[0054] Furthermore, the turnbuckle 61 uses an M24 adjusting bolt, including an adjusting rod and a tie rod. The adjusting rod is of a uniform specification, while the tie rod is available in various lengths to accommodate precast base plates with different span sizes.

[0055] Furthermore, the hollow pressure bar 62 is made of a round steel tube with an outer diameter of 40mm and a wall thickness of 5mm. Bolt holes are provided at both ends, and it is connected to the lifting eye bolt 5 and the triangular connecting plate 63 by bolts. Its slenderness ratio is controlled below 80.

[0056] Furthermore, the triangular connecting plate 63 is made of Q355 steel plate with a thickness of 20mm, which is formed by laser cutting.

[0057] As one embodiment, the present invention also provides a construction method for a tensioned truss support device, the specific implementation process of which can be divided into a prefabrication stage, a transportation and hoisting stage, an on-site installation stage, a cast-in-place layer construction stage, and a support removal stage according to the construction process.

[0058] During the prefabrication stage, the prefabricated base slab 1, Y-shaped shear key 2, and ribbed bolt sleeve 4 are manufactured in the prefabrication plant using a standardized production line. The Y-shaped shear key 2 is formed by bending and welding HRB400 grade steel bars, with cross-shaped anchor bars welded to its bottom to enhance pull-out resistance. The ribbed bolt sleeve 4 has four stiffening ribs welded to its outer side. High-strength steel molds are used, with dimensional errors controlled within ±1mm. A special release agent is applied to the mold surface to ensure demolding quality. When manufacturing the prefabricated base slab 1, firstly, the lower layer of steel mesh is arranged orthogonally in both directions, selecting appropriate steel bar diameters and spacing according to design requirements, with a protective layer thickness of 15mm. Secondly, the Y-shaped shear key 2 is arranged at the designed position, with the bottom cross-shaped reinforcing bars of the Y-shaped shear key 2 welded to the lower layer of steel mesh, and the top support exposed to the height of the top layer of steel mesh. Then, the ribbed bolt sleeve 4 is arranged at the designed position, with its sidewalls welded to the bottom layer of steel mesh, the bottom of the sleeve tightly against the formwork, and the top of the sleeve exposed for 10-20mm. The stiffening ribs enhance the pull-out resistance of the lifting points and improve the shear strength of the overlapping surfaces. Both ends of the ribbed bolt sleeve 4 must be sealed with rubber to prevent concrete from seeping into the sleeve during pouring. Finally, well-mixed fine aggregate concrete is poured and compacted using a high-frequency vibrator. During vibration, special attention is paid to ensuring the area around the embedded parts is dense to avoid voids. Immediately after pouring, the surface is roughened, then covered with a curing film for steam curing. Demolding is performed after 24 hours, and the concrete strength must reach at least 75% of the design strength at demolding. During lifting, the lifting eye bolts 5 are anchored via the ribbed bolt sleeve 4. The hook only needs to be connected to the lifting eye bolts 5 for lifting. After lifting, the lifting eye bolts 5 are removed.

[0059] During the transportation and hoisting phase, the precast base plate 1 is laid flat on a special transport vehicle, with wooden blocks used as spacers between layers. The height of the wooden blocks should exceed the Y-shaped shear key by at least 230mm to ensure that the shear key is not damaged. During transportation, the vehicle speed should be controlled to avoid severe bumps that could cause damage to the edges and corners. During hoisting, the lifting eye bolts 5 are anchored to the ribbed bolt sleeves 4 at the four corners. The hook is connected to the lifting eye bolts 5 and lifted horizontally. The hook is slowly raised, and after 0.5m off the ground, it is paused to check whether the force on the lifting points is even. If there are no problems, hoisting continues. A laser positioning device is used for assistance during positioning, and the installation error is controlled within ±3mm. After installation, the lifting eye bolts 5 are removed.

[0060] During the on-site installation phase, the tensioned truss support device 6 includes a three-point support system and a four-point support system. When the span of the precast base slab 1 is ≤4m, the three-point support system is adopted, which consists of two turnbuckles 61, one hollow compression bar 62 and one triangular connecting plate 63. When the span of the precast base slab 1 is >4m, the four-point support system is adopted, which consists of three turnbuckles 61, two hollow compression bars 62 and two triangular connecting plates 63. First, anchor the lifting eye bolt 5 to the lower part of the ribbed bolt sleeve 4, with the lifting eye direction aligned with the span direction of the precast base slab 1. Second, install the hollow compression member 62, connecting both ends of the hollow compression member 62 to the lifting eye bolt 5 and the triangular connecting plate 63 respectively using bolts. Then, install the turnbuckle 61, connecting both ends of the turnbuckle 61 to the lifting eye bolt 5 and the triangular connecting plate 63 respectively using bolts. Adjust the turnbuckle 61 to tighten the tensioned truss support device 6 and ensure the hollow compression member 62 is vertical; at this point, the tensioned truss support device 6 is installed. Finally, adjust the turnbuckle 61 to slowly arch the precast base slab 1. To ensure the floor slab is level after pouring, adjust the arching amplitude according to the load conditions and verify it using a laser rangefinder. After arching, directly erect the tied steel mesh on top of the Y-shaped shear key 2, eliminating the need for stirrup reinforcement. The steel mesh must be tied to the Y-shaped shear key 2.

[0061] During the cast-in-place layer construction phase, wooden formwork is used to support the perimeter of the pouring area, and the concrete pouring thickness is marked. Fine aggregate concrete is pumped and poured to the marked height. A vibrator is used to compact the concrete, avoiding contact with the support system during vibration. Finally, a finishing treatment is applied. After pouring, the concrete is covered with geotextile for insulation and curing for 7 days. Once the cast-in-place layer strength meets the design requirements, the tensioned truss support device can be removed.

[0062] During the support dismantling phase, first loosen the turnbuckle 61 simultaneously, and slowly release the prestress by slightly rotating the adjusting rod each time, completing the prestress release in 3-4 stages. After the prestress release is completed, first remove the connecting bolts of the triangular connecting plate 63 to make the turnbuckle 61 and the hollow pressure rod 62 independent of each other. Then, remove the lifting eye bolts 5 sequentially from the middle of the span to both ends to separate the turnbuckle 61 and the hollow pressure rod 62 from the precast base plate 1. After all dismantled components are inspected and cleaned, apply anti-rust oil, replace damaged components in a timely manner, and classify and store good components for reuse.

[0063] Finally, it should be noted that the dimensions, quantity, material strength grade, and other parameters of the components involved in this application, such as Y-type shear keys, concrete ribbed beams, ribbed bolt sleeves, eye bolts, turnbuckles, hollow compression members, and triangular connecting plates, can all be adjusted according to actual needs. In addition, the self-balancing tensioned truss support device provided in this application can also be used for support in other prefabricated floor construction stages, which can significantly improve construction efficiency and reduce construction costs.

[0064] The technical means employed in this invention include: setting a Y-shaped shear key that serves both shear resistance and positioning of the upper reinforcing mesh; configuring ribbed bolt sleeves as multi-functional connection nodes; using concrete rib beams to enhance the rigidity of the precast base slab; and achieving adjustable pre-camber of the precast base slab through turnbuckles in a tensioned truss support device. The synergistic effect of these technical means enables this invention to significantly reduce steel consumption by approximately 20% while ensuring structural load-bearing capacity, improve construction efficiency, and achieve standardized reusability of the support system, thus achieving the technical effects of material saving, cost reduction, and environmental friendliness.

[0065] The purpose of this invention is to overcome the technical defects of traditional reinforced concrete composite slabs, such as low material utilization, poor mechanical properties, and low construction efficiency, and to provide an economical, efficient, structurally sound, and easy-to-construct composite slab without truss reinforcement and its matching tensioned truss support device 6. In traditional composite slabs, the amount of truss reinforcement accounts for about 25% of the total steel consumption of the floor slab, but it usually cannot fully play its role in load-bearing during design calculations, resulting in serious resource waste. At the same time, the upper chord reinforcement of the truss reinforcement is prone to buckling instability when under compression at mid-span, affecting structural safety. Traditional full-span scaffolding support systems consume a large amount of materials, have a long erection period, and are troublesome to dismantle, which seriously restricts the promotion and application of prefabricated buildings.

[0066] To achieve the aforementioned objectives, this invention employs a dual approach of structural innovation and construction process optimization to address existing technical problems. Regarding structural innovation, this invention completely eliminates traditional truss reinforcement, innovatively using a Y-shaped shear key 2 to replace the shear resistance function of traditional truss reinforcement, while also serving as a positioning element for the upper reinforcement mesh, effectively improving the shear resistance of the composite surface. The design incorporates a non-reinforced concrete ribbed beam 3 integrally cast with the precast base slab 1, enhancing the strength and stiffness of the precast base slab 1 to prevent cracking, and improving the load-bearing capacity of the lifting point area to ensure lifting safety. A ribbed bolt sleeve 4 is used as a multi-functional connecting component, achieving an integrated design for lifting, support connection, and shear reinforcement. In terms of construction process optimization, this invention has developed a detachable tensioned truss support device 6, which is a self-balancing support system composed of turnbuckles 61, hollow compression bars 62 and triangular connecting plates 63. It can be quickly connected by bolts of standardized components, completely replacing the traditional full-span scaffolding. The turnbuckles 61 can be used to precisely adjust the precast base plate 1 to achieve pre-arching, offset the deformation of the cast-in-place layer load and ensure zero deflection of the floor slab.

[0067] This invention achieves dual optimization of material conservation and structural performance through the comprehensive application of the aforementioned technical means. The truss-free design directly saves approximately 20% of steel, and the reduction of the precast base slab 1 thickness to 40-60mm further reduces the structure's self-weight. The synergistic work of the Y-shaped shear key 2 and the ribbed bolt sleeve 4 effectively improves the shear bearing capacity of the composite surface, avoiding the risk of instability under compression of the upper chord reinforcement in traditional slender trusses. The adoption of the tensioned truss support device 6 significantly improves construction efficiency, eliminating the need for full-span scaffolding and shortening installation time. Standardized component design enhances versatility and reusability, achieving green construction and sustainable development. The entire technical solution forms a complete process flow from prefabrication, transportation and hoisting, on-site installation to construction and dismantling, providing an economical, efficient, and environmentally friendly systematic solution for prefabricated building floor structures.

[0068] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0069] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A composite slab without truss reinforcement, characterized in that, It includes a precast base plate (1), a Y-shaped shear key (2), a concrete rib beam (3), and a ribbed bolt sleeve (4); with the upper horizontal surface of the precast base plate (1) as the surface and the lower horizontal surface as the bottom surface; The precast base plate (1) has a built-in bidirectional reinforcing steel mesh; The Y-shaped shear key (2) is embedded in the precast base plate (1), with its lower part anchored in the precast base plate (1) and its upper part extending out of the surface of the precast base plate (1); The concrete rib beam (3) and the precast base plate (1) are integrally cast, and no steel bars are installed inside the concrete rib beam (3); The ribbed bolt sleeve (4) is arranged inside the precast base plate (1). The ribbed bolt sleeve (4) penetrates the precast base plate (1) along the thickness direction and is located in the area of ​​the concrete rib beam (3). The lower end of the ribbed bolt sleeve (4) is flush with the bottom surface of the precast base plate (1), and the upper end extends beyond the top surface of the concrete rib beam (3).

2. The trussless composite slab according to claim 1, characterized in that, It has a post-cast layer with a steel mesh on it. The structure of the steel mesh at the distance from the outer surface of the concrete is a protective layer. The Y-shaped shear key (2) is formed by bending and welding steel bars. The upper support of the Y-shaped shear key (2) matches the height of the upper steel mesh and the thickness of the protective layer.

3. The trussless composite slab according to claim 1, characterized in that, The length direction of the concrete rib beam (3) is consistent with the long side direction of the precast base plate (1), the long side of the concrete rib beam (3) is parallel to the long side of the precast base plate (1), and the length of the concrete rib beam (3) exceeds 3 / 4 of the span of the precast base plate (1); there are at least two concrete rib beams (3) and they are parallel to each other.

4. The trussless composite slab according to claim 1, characterized in that, The ribbed bolt sleeve (4) has a continuous thread inside and four stiffening ribs on the outside. The upper end of the ribbed bolt sleeve (4) extends 10-20mm beyond the top surface of the concrete rib beam (3). Both the upper and lower ends of the ribbed bolt sleeve (4) can be used to anchor bolts.

5. The trussless composite slab according to claim 1, characterized in that, The precast base plate (1) is made of C30-C50 concrete with a thickness of 40-60mm.

6. The trussless composite slab according to claim 2, characterized in that, The Y-shaped shear key (2) is made of HRB400 grade steel bars with a diameter of not less than 15mm, a height of 80-100mm, and is arranged at intervals of 400-600mm.

7. A tensioned truss support device formed using a truss-less composite slab as described in any one of claims 1 to 6, characterized in that, The tensioned truss support device (6) used for the span of the composite slab without truss reinforcement includes: The cable-stayed truss support device, consisting of a turnbuckle (61), a hollow compression bar (62), and a triangular connecting plate (63), adopts a three-point support structure or a four-point support structure depending on the span of the precast base plate. When the span of the precast base plate (1) is less than or equal to 4m, the three-point support includes two turnbuckles (61), a hollow pressure bar (62), and a triangular connecting plate (63); The triangular connecting plate (63) has three connection points. The hollow pressure bar (62) is perpendicular to the trussless composite plate. One end of the hollow pressure bar (62) is connected to the bottom end of the trussless composite plate, and the other end of the hollow pressure bar (62) is fixed to the connection point of the triangular connecting plate (63). The two ends of the turnbuckle (61) are respectively connected to the other connection point of the triangular connecting plate (63) and the bottom end of the composite slab without truss reinforcement; the two turnbuckles (61) are symmetrically and obliquely arranged on both sides of the span direction of the precast base plate (1); When the span of the precast base plate (1) is greater than 4m, the four-point support includes three turnbuckles (61), two hollow pressure bars (62) and two triangular connecting plates (63); one turnbuckle (61) is arranged horizontally in the middle of the span, and the two turnbuckles (61) on both sides are arranged obliquely and symmetrically; the two hollow pressure bars (62) are vertically placed directly below the ribbed bolt sleeve (4) at 1 / 3 span of the composite slab without truss reinforcement; the two triangular connecting plates (63) are located at 1 / 3 span of the composite slab without truss reinforcement to connect the hollow pressure bars (62) and the turnbuckles (61).

8. The tensioned truss support device according to claim 7, characterized in that, The basket screw (61) includes an adjusting rod and a pull rod. The adjusting rod is located in the middle of the pull rod and its length is adjusted by rotation.

9. The tensioned truss support device according to claim 7, characterized in that, The hollow pressure bar (62) has bolt holes at both ends. The hollow pressure bar (62) is connected to the lifting eye bolt (5) and the triangular connecting plate (63) by bolts. The slenderness ratio of the hollow pressure bar (62) is controlled to be below 80.

10. A construction method, employing the tensioned truss support device according to any one of claims 7 to 9, characterized in that, Y-shaped shear keys (2) and ribbed bolt sleeves (4) are pre-embedded during the prefabrication stage. During hoisting, the lifting ring bolts (5) are anchored through the ribbed bolt sleeves (4) and connected to the hook. During construction, the tensioned truss support device is adjusted on-site to make the prefabricated base plate (1) arch. After construction is completed, the tensioned truss support device is removed and reused.

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