Truss-supported precast composite hollow floor slab

Abstract

This invention discloses a truss-supported precast composite hollow floor slab, comprising: several parallel precast beams fixed to several structural columns; several parallel precast composite floor slabs with their bottom ends placed on the precast beams; at least two truss mesh panels fixed on the precast composite floor slabs; each truss mesh panel includes a truss top chord, several web member connecting supports, and several truss web members; all truss mesh panels and the precast composite floor slabs together form a truss load-bearing structure; box-type core templates are fixed in a matrix on the upper surface of the precast composite floor slabs; and a cast-in-place concrete layer, including concrete hidden beams cast within the intervals of the box-type core templates; the top surface of the cast-in-place concrete layer is higher than the top surface of the precast beams but lower than the connection points between the web member connecting supports and the truss web members. This invention combines the advantages of the truss beam hollow floor slab construction method, the precast composite slab construction method, and the truss load-bearing structure, enabling the construction of truss beam hollow floor slabs without lower supports.

Description

Technical Field

[0001] This invention relates to the field of prefabricated building construction. More specifically, this invention relates to a truss-supported prefabricated composite hollow floor slab. Background Technology

[0002] A floor slab is a specialized floor structure at the top of a building. During the building's use, it needs to bear various loads such as the foundations of mechanical and electrical equipment, equipment rooms, waterproofing structures, personnel, and construction machinery on the floor. The stress requirements are much greater than those of ordinary floor slab structures. In current construction techniques, a common approach is to construct a supporting frame before pouring the floor slab as a whole. In addition to the need for on-site support frame construction, this process also requires additional support frames because the thickness and dimensions of the floor slab are larger than those of a standard floor slab, making it impossible to directly use the support methods of a standard floor slab.

[0003] Currently, in order to reduce the self-weight of the floor slab and reduce the support system while ensuring the load-bearing capacity and stiffness of the floor slab, the hollow beam slab is gradually being applied to various projects. This type of floor slab forms a grid-like beam group under the relatively thin floor slab surface by setting box-type core molds at intervals when supporting the slab formwork. While the load-bearing capacity of the floor slab is basically the same as that of a monolithic cast-in-place floor slab of the same thickness, the self-weight of the floor slab is greatly reduced, which also reduces the amount of engineering work for the support frame before the floor slab is poured. However, this type of process still requires the support below, and since the floor slab is the top layer of the building slab structure, it is often required that the support can only be removed when the floor slab concrete strength reaches 100%, which also affects the construction flow.

[0004] The invention patent application CN106088434 A discloses a prefabricated steel structure composite hollow floor slab and its construction method, including steel beams, precast base slabs, rib beams, infill material, and cast-in-place concrete layers. The inter-column steel beams can support the precast slabs during construction, eliminating the need for on-site formwork and allowing for rapid construction. However, this type of hollow floor slab requires the base slab between the column grids to be precast and hoisted as a whole, making it only suitable for small column grids. For large column grids, the transportation and installation of the precast base slabs present significant difficulties. Furthermore, since the precast base slab can be considered a conventional composite slab, a large amount of lower support is still required for pouring, resulting in poor applicability.

[0005] Therefore, it is necessary to propose a new type of floor slab and a corresponding construction method, which can not only fundamentally reduce the amount of supporting structure, but also facilitate on-site assembly and construction. Summary of the Invention

[0006] One objective of this invention is to provide a truss-supported precast composite hollow floor slab. This invention combines the advantages of a grid beam hollow floor slab construction method, a precast composite slab construction method, and truss stress distribution, enabling the construction of a grid beam hollow floor slab without lower support.

[0007] To achieve these and other advantages according to the invention, according to one aspect of the invention, the invention provides a truss-supported precast composite hollow floor slab, comprising:

[0008] Several parallel precast beams are fixed to several completed structural columns; several precast composite floor slabs are spliced ​​side by side, with the long sides of the precast composite floor slabs spliced ​​to the long sides of other precast composite floor slabs, and the two short ends of the bottom surface placed on two parallel precast beams; at least two parallel truss mesh panels are fixed to the upper surface of the precast composite floor slabs, each truss mesh panel including a truss top chord that is higher than the upper surface of the precast composite floor slab and parallel to the long side of the precast composite floor slab, several web member connecting supports, and several truss web members. The web member connecting supports are fixed to the precast composite floor slabs in a row at intervals. One or more truss web members are detachably fixed between the rod connecting support and the upper chord of the truss. Several truss connecting rods connect any two adjacent truss meshes. All truss meshes and the precast composite floor slab together form a truss load-bearing structure. Several box-type core templates are fixed in a matrix on the upper surface of the precast composite floor slab. A cast-in-place concrete layer is formed above the precast composite floor slab. The cast-in-place concrete layer includes concrete hidden beams cast within the intervals of the box-type core templates. The top surface of the cast-in-place concrete layer is higher than the top surface of the precast beams but not higher than the connection between the web member connecting support and the truss web member.

[0009] Preferably, the precast beam is a steel beam structure, with flanges extending from the bottom of the beam body to both sides, and the flanges of any two adjacent precast beams supporting several precast composite floor slabs spliced ​​side by side.

[0010] Preferably, the web member connecting support includes a support fixing plate and two first sleeves. The support fixing plate is fixed to the upper surface of the precast composite floor slab, and the two first sleeves are symmetrically welded to the support fixing plate. The truss upper chord includes several sets of downwardly inclined second sleeves, with each second sleeve and the first sleeve being coaxially opposite. Both ends of the truss web member are provided with external threads, and the second sleeves and first sleeves are provided with internal threads that match the truss web member. Both ends of the truss web member are matched and screwed into the corresponding second sleeves and first sleeves. When the truss web member is screwed to the top in the direction of one of the corresponding first sleeves or second sleeves, one end of the truss web member is in a disengaged state.

[0011] Preferably, the truss upper chord includes alternating threaded main chord tubes and chord connecting tubes, with matching threads at both ends of the main chord tubes and chord connecting tubes. The main chord tube has two second sleeves connected obliquely downward in the middle of its body. Each main chord tube is located directly above the midpoint of the connecting support of two adjacent web members in the same row. The two second sleeves on the main chord tube are screwed together with the opposite first sleeve to enclose the truss web members.

[0012] Preferably, two connecting rod sleeves are fixed on both horizontal sides of the middle of the main tube of the chord. The connecting rod sleeves are provided with internal threads, and the two ends of the truss connecting rod are provided with external threads. A truss connecting rod is threadedly connected between any two opposite connecting rod sleeves of the same precast composite floor slab.

[0013] Preferably, the truss upper chord, truss web members, and truss connecting rods are all steel tubular structures.

[0014] Preferably, the construction method for the above-mentioned truss-supported precast composite hollow floor slab includes the following steps:

[0015] S1. Based on the beam and column layout of the building, the on-site hoisting capacity, and the stress calculation results, design the dimensions of the precast composite floor slabs and precast beams. After all components are processed in the precast component processing plant, they are sent to the construction site.

[0016] S2. At the construction site, according to the design requirements, the main chord tube and the connecting tube of the chord are screwed in sequence at intervals to form a single integral truss upper chord and temporarily supported. After the corresponding number of web member connecting supports are placed in place, the corresponding number of truss web members are connected between the web member connecting supports and the truss upper chord to form a truss mesh.

[0017] S3. Tighten the truss connecting rods between several truss meshes belonging to the same precast composite floor slab, and then fix the bottom surface of the support fixing plate to the precast composite floor slab.

[0018] S4. Hoist all precast beams onto the fixed structural columns, then hoist the precast composite floor slabs in sequence and place them on the flanges of two adjacent precast beams until all precast composite floor slabs are hoisted.

[0019] S5. On the surface of the precast composite floor slab between any two truss mesh panels, box-type core templates are fixed in parallel at intervals.

[0020] S6. Fix the hidden beam reinforcement cage in the space between any two columns of box core formwork, then support the slab reinforcement and run water and electricity pipes.

[0021] S7. Seal the joint between any two adjacent precast composite floor slabs, seal the gap between the box core formwork and the upper surface of the precast composite floor slab, and pour the cast-in-place concrete layer.

[0022] S8. Cure the cast-in-place concrete layer until it reaches the design strength requirement, then remove all truss upper chords and truss web members, fill the first sleeve with grouting material to seal it, and complete the floor slab construction.

[0023] Preferably, in step S5, the steel-adhesive is applied to the bottom surface of the support fixing plate to fix it to the upper surface of the precast composite floor slab.

[0024] Preferably, in step S7, the spacing between any two box-shaped core templates is the same.

[0025] The present invention has at least the following beneficial effects:

[0026] First, the precast composite floor slab used in this invention, together with several truss mesh panels above, can be regarded as a truss load-bearing structure in actual stress. The weight of the cast-in-place concrete layer is distributed to the truss mesh panels connected to the precast composite floor slab and transferred to the precast beams that have been fixed. The stiffness of this precast composite floor slab is greatly improved compared with conventional composite slabs, which can effectively place box core formwork and pour concrete. This invention combines the advantages of the hollow beam floor slab construction method, the precast composite slab construction method, and the truss load-bearing structure, and can realize the construction of hollow beam floor slabs without lower support.

[0027] Secondly, the web member connecting support of the present invention is detachably connected to the web member of the truss, and the connection part is higher than the cast-in-place concrete layer. After the cast-in-place concrete layer reaches a certain strength, the web member and the main chord of the truss can be manually removed, saving construction materials.

[0028] Third, this invention does not require support from below, so the relevant procedures for the top floor can be arranged before the concrete strength of the floor slab reaches the requirements for demolding, and the demolding work does not affect the construction work of the top floor, thus significantly shortening the construction period.

[0029] Fourth, the present invention uses a truss load-bearing structure formed by the truss upper chord, truss web members, and precast composite floor slabs to bear the load of the cast-in-place concrete layer and the corresponding construction load. The height of the truss upper chord determines the stiffness of the overall load-bearing structure. Therefore, precast composite floor slabs of the same size and specifications can be used for different floor slab design thicknesses. When the weight of the cast-in-place concrete layer increases, the stiffness and load-bearing capacity can be adjusted by adjusting the setting height of the truss upper chord, the length of the truss web members, and the spacing of the web member connecting supports.

[0030] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the hoisting of prefabricated composite floor slabs in one technical solution of the present invention;

[0032] Figure 2 This is a schematic diagram showing the completion of the hoisting of a prefabricated composite floor slab in one technical solution of the present invention;

[0033] Figure 3 This is a top view of the prefabricated composite floor slab after hoisting in one technical solution of the present invention;

[0034] Figure 4 This is a side view of the prefabricated composite floor slab after hoisting in one of the technical solutions of the present invention;

[0035] Figure 5 This is a schematic diagram of the completed cast-in-place concrete layer in one technical solution of the present invention;

[0036] Figure 6 This is a schematic diagram of a prefabricated composite floor slab in one technical solution of the present invention;

[0037] Figure 7 This is a schematic diagram of the installation of a box-shaped core template for a prefabricated composite floor slab in one technical solution of the present invention;

[0038] Figure 8 This is a side view of the disassembled truss mesh in one technical solution of the present invention;

[0039] Figure 9 This is a schematic diagram of the assembly of prefabricated composite floor slabs in one technical solution of the present invention;

[0040] Figure 10 This is a schematic diagram of the precast composite floor slab before pouring in one technical solution of the present invention;

[0041] Figure 11 This is a schematic diagram of the disassembly of the precast composite floor slab before pouring in one technical solution of the present invention;

[0042] Figure 12 This is a schematic diagram of the precast composite floor slab after casting in one technical solution of the present invention;

[0043] Figure 13 This is a schematic diagram showing the disassembly of a precast composite floor slab after casting, according to one technical solution of the present invention.

[0044] Figure 14 This is a schematic diagram of the installation of truss mesh on a precast composite floor slab in one technical solution of the present invention;

[0045] Figure 15 This is a schematic diagram of the web member connection support in one technical solution of the present invention;

[0046] Figure 16 This is a side view of the state of the prefabricated composite floor slab corresponding to each process in one of the technical solutions of the present invention.

[0047] Legend: 1-truss mesh, 10-web member connection support, 101-support fixing plate, 102-first sleeve, 11-truss upper chord, 111-chord main sleeve, 112-chord connecting sleeve, 12-truss web member, 120-second sleeve, 13-truss tie rod, 130-tie rod sleeve, 2-precast composite floor slab, 3-box core formwork, 31-box core formwork at joint, 4-cast-in-place concrete layer, 41-concrete hidden beam, 411-cavity, 42-concrete surface layer, 5-reinforced concrete, 51-hidden beam reinforcement cage, 52-slab reinforcement, 6-precast beam, 61-flange plate, 7-structural column. Detailed Implementation

[0048] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can implement it based on the description.

[0049] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0050] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are conventional methods, and the reagents and materials mentioned are commercially available. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "setting" should be interpreted broadly. For example, they can refer to fixed connection or setting, detachable connection or setting, or integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The terms "lateral," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description. They 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 this invention.

[0051] like Figures 1-16 As shown, the present invention provides a truss-supported precast composite hollow floor slab, comprising:

[0052] Several parallel precast beams 6 are fixed to several completed structural columns 7; several precast composite floor slabs 2 are spliced ​​side by side, with the long side of each precast composite floor slab 2 spliced ​​to the long side of the other precast composite floor slabs 2, and the two short sides of the bottom surface placed on two parallel precast beams 6. At least two parallel truss mesh panels 1 are fixed to the upper surface of the precast composite floor slabs 2. Each truss mesh panel 1 includes a truss upper chord 11 that is higher than the upper surface of the precast composite floor slab 2 and parallel to the long side of the precast composite floor slab 2, several web member connecting supports 10, and several truss web members 12. The web member connecting supports 10 are fixed to the precast composite floor slabs 2 in a row at intervals. Each web member connects to the upper chord 11 of the precast composite floor slab 2. One or more truss web members 12 are detachably fixed between the support 10 and the upper chord 11 of the truss. Several truss connecting rods 13 connect any two adjacent truss meshes 1. All truss meshes 1 and the precast composite floor slab 2 together form a truss load-bearing structure. Several box-type core templates 3 are fixed in a matrix on the upper surface of the precast composite floor slab 2. A cast-in-place concrete layer 4 is formed above the precast composite floor slab 2. The cast-in-place concrete layer 4 includes concrete hidden beams 41 cast within the intervals of the box-type core templates 3. The top surface of the cast-in-place concrete layer 4 is higher than the top surface of the precast beam 6 but not higher than the connection between the web member connecting support 10 and the truss web member 12.

[0053] In this technical solution, the structural column 7 is a cast-in-place or precast column component that has been completed on the top floor. Its strength and fixing methods meet the requirements for bearing the entire floor design load. The structural column 7 forms a column grid on the top floor. The precast beam 6 is a component that needs to be precast. It is a steel structure or reinforced concrete structure and is connected to the structural column 7 through on-site grouting or steel structure joints. The precast beam 6 can adopt a structure that requires secondary concrete pouring to form a complete beam, so as to better cooperate with the cast-in-place concrete layer 4 on the precast composite floor slab 2. The precast beam 6 itself has load-bearing capacity and can bear the allocated floor load. The composite floor slab 2 is an internally reinforced long concrete slab. Additional reinforcement can be added inside for the fixing position of the subsequent web member connection support 10. The two short sides of the precast composite floor slab 2 are placed on two precast beams 6. If the long side of the precast composite floor slab 2 has no protruding reinforcement, the adjacent slabs are tightly spliced. If the long side of the precast composite floor slab 2 is designed with protruding reinforcement, there is a certain gap between the adjacent precast composite floor slabs 2 to form a post-pouring strip. The protruding reinforcement is 100% lapped. Optionally, in addition to the two short sides of the precast composite floor slab 2 being placed on the precast beams 6, the bottom of the slab can also be fixed to other precast beams 6.

[0054] In this technical solution, the truss upper chord 11, truss web members 12, and truss connecting rods 13 in the truss mesh 1 are made of finished steel pipes or shaped steel. The truss web members 12 and truss connecting rods 13 are connected to the truss upper chord 11 by bolts or threaded sleeves, and their connection forms are similar to the node forms of steel structure trusses. The web member connecting support 10 is a component made of steel plate or steel pipe, and its end to the truss web member 12 can be connected by bolts or threaded sleeves. The connection is made in a certain way. The web member connecting support 10 and the top surface of the precast composite floor slab 2 can be fixed by anchoring adhesive or expansion bolts. In terms of stress consideration, the truss mesh 1 can be regarded as a single steel pipe truss piece with a simplified lower chord. Since the precast composite floor slab 2 can be regarded as a lower chord structure, when the slab reinforcement construction and the concrete cast-in-place layer 4 are carried out, the precast composite floor slab 2 and its upper truss mesh 1 are combined to bear the force, and the stiffness and bearing capacity are greatly improved compared with conventional composite floor slabs.

[0055] Stiffness refers to the ability of an object to resist deformation when subjected to external forces. The stiffness of a truss structure is closely related to its load-bearing capacity. In this technical solution, since the distance between the upper chord 11 of the truss and the precast composite floor slab 2 determines the stiffness of the truss mesh 1, precast composite floor slabs 2 of the same thickness can be used for different floor slab design thicknesses. When the thickness and weight of the cast-in-place concrete layer 4 increase, the overall load-bearing capacity can be improved by adjusting the relative setting height of the upper chord 11 of the truss with respect to the precast composite floor slab 2, the length of the corresponding truss web members 12, and the spacing of the web member connecting supports 10. Since the upper chord 11, the truss web members 12, and the web member connecting supports 10 are all detachable components, operators can quickly adjust and assemble them. Optionally, a rod structure can be added between any two web member connecting supports 10 to further improve the overall stiffness and strength.

[0056] In this technical solution, the truss mesh panels 1 are all vertically fixed to the precast composite floor slab 2. The box-type core template 3 is a square or rectangular hollow box made of metal or sheet metal, which can be placed between any two adjacent truss mesh panels 1 and fixed to the precast composite floor slab 2 by bolts or adhesive. Hidden beam reinforcement cages 51 are placed in the gaps between the box-type core templates 3, and after concrete is poured, it becomes a concrete hidden beam 41. The area above the top surface of the box-type core template 3 is the concrete surface layer 42. Figure 5As shown, after the completion of the cast-in-place concrete layer 4, the floor slab has several spaced cavities 411 formed between the concrete hidden beams 41, the concrete surface layer 42, and the precast composite floor slab 2 due to the box core formwork 3. The floor slab's stiffness and load-bearing capacity are not significantly weakened, while its self-weight is greatly reduced. Both ends of each concrete hidden beam 41 are cast together with the precast beam body 6, which serves as the main beam, during the construction of the cast-in-place concrete layer 4. The several concrete hidden beams 41 forming a network can effectively bear the load of the floor slab during subsequent use and transfer it to its main load-bearing structure. Optionally, the box core formwork 3 can be made of square boxes of the same specifications arranged at equal intervals in the horizontal and vertical directions to form a network of concrete hidden beams 41 of equal intervals and sizes. Alternatively, hexagonal, octagonal, or other shaped box core formwork 3 can be used to form a dense ribbed load-bearing structure of different shapes of concrete hidden beams 41.

[0057] In this technical solution, since the web member connecting support 10 and the truss web member 12 are detachably connected, and the connection point between the web member connecting support 10 and the truss web member 12 is higher than the top surface elevation of the cast-in-place concrete layer 4, the web member connecting support 10, except for the connection point with the truss web member 12, is cast inside the cast-in-place concrete layer 4. Before the cast-in-place concrete layer 4 solidifies and reaches the demolding strength, the load is borne by the truss mesh 1 and the precast composite floor slab 2. After the cast-in-place concrete layer 4 reaches the demolding strength, the connection between the web member connecting support 10 and the truss web member 12 is released, and the cast-in-place concrete layer 4 and the precast composite floor slab 2 cast integrally with it bear the self-weight and the load on it. The precast composite floor slab 2 used in this invention, together with several truss mesh 1 above it, can be regarded as a truss load-bearing structure in actual stress. The weight of the cast-in-place concrete layer 4 is distributed among the precast composite floor slab 2 and the precast composite floor slab 2. The truss mesh 1 connected to the cover plate 2 is transferred to the precast beam 6 and structural column 7 that have been fixed. The stiffness of the truss load-bearing structure formed by the precast composite floor slab 2 after the addition of the truss mesh 1 is greatly improved compared with the conventional single composite slab. It can effectively place the box core formwork 3, tie the reinforcing steel 5 and pour concrete. Moreover, due to the detachable design of the truss mesh 1 itself, the truss mesh 1 and the precast composite floor slab 2 are also detachable. The stiffness of the truss load-bearing structure composed of the truss mesh 1 and the precast composite floor slab 2 can be easily adjusted. This invention combines the advantages of the hollow beam floor slab construction method, the precast composite slab construction method and the truss load-bearing form, and can realize the construction of the hollow beam floor slab without the lower support. It fundamentally solves the problems of the large amount of lower support used in conventional processes and the inability to perform additional processes on the top layer before demolding.

[0058] In another technical solution, the precast beam 6 is a steel beam structure. Flange plates 61 extend from the bottom surface of the precast beam 6 to both sides. The flange plates 61 of any two adjacent precast beams 6 support several precast composite floor slabs 2 joined side-by-side. The precast beam 6 is a single, continuous steel section with an I-shaped or rectangular cross-section. The precast beam 6 has a relatively light self-weight and high load-bearing capacity. The precast beam 6 is fixedly connected to the structural columns 7 by bolts or welding. The bottom surface of the precast beam 6 extends laterally outwards to both sides. The two short ends of the precast composite floor slab 2 are placed on the flange plate 61. Before the construction of the cast-in-place concrete layer 4, the hidden beam reinforcement cage 51 and the slab reinforcement 52 tied on the precast composite floor slab 2 can be fixed to the precast beam body 6 by welding or anchoring to improve the strength at the beam-slab joint. Optionally, the beam body of the precast beam body 6 has horizontal through holes. When tying the reinforcement, the precast composite floor slab 2 on both sides of the precast beam body 6 can use the horizontal through holes on the precast beam body 6 to connect the reinforcement on both sides.

[0059] In this technical solution, the precast beam 6 and the cast-in-place concrete layer 4 together form the load-bearing main beam in a general floor structure, while the concrete hidden beam 41 can be regarded as a secondary beam. The precast beam 6 of the steel beam structure is equivalent to the steel reinforcement structure in a general main beam. Since the precast composite floor slabs 2 on both sides are placed and attached to the flange plate 61, it is only necessary to properly seal the joint position before pouring concrete without additional formwork support.

[0060] In another technical solution, the web member connecting support 10 includes a support fixing plate 101 and two first sleeves 102. The support fixing plate 101 is fixed to the upper surface of the precast composite floor slab 2, and the two first sleeves 102 are symmetrically welded to the support fixing plate 101. The truss upper chord 11 includes several sets of downwardly inclined second sleeves 120. The second sleeves 120 and the first sleeves 102 are coaxially opposite each other. The two ends of the truss web member 12 are provided with external threads, and the second sleeves 120 and the first sleeves 102 are provided with internal threads that match the truss web member 12. The two ends of the truss web member 12 are matched and screwed into the corresponding second sleeves 120 and first sleeves 102. When the truss web member 12 is screwed to the top in the direction of one of the corresponding first sleeves 102 and second sleeves 120, one end of the truss web member 12 is in a disengaged state. In this technical solution, the support fixing plate 101 is... The truss web members are cut from finished steel plates. The first sleeve 102 and the second sleeve 120 are finished steel pipe sections with internal threads. The truss web members 12 are round rods or round tubes. Both ends of the truss web members 12 are provided with external threads that match the first sleeve 102 and the second sleeve 120 respectively. The direction in which one end of the truss web members 12 is screwed into the first sleeve 102 is opposite to the direction in which the other end is screwed into the second sleeve 120. After one end of the truss web members 12 is screwed into the bottom of the second sleeve 120 in the positive direction, the first sleeve 102 of the web member connecting support 10 is aligned with the other end of the truss web members 12. At this time, the truss web members 12 are screwed in the opposite direction. Both ends of the truss web members 12 are screwed out of the second sleeve 120 and screwed into the first sleeve 102 respectively. The distance between the truss web members 12 and the second sleeve 120 and the first sleeve 102 needs to be calculated to avoid the slip sleeves from coming off under load.

[0061] In another technical solution, the upper chord 11 of the truss includes an alternating threaded chord main tube 111 and a chord connecting tube 112. The two ends of the chord main tube 111 and the chord connecting tube 112 are provided with matching threads. The middle of the chord main tube 111 is obliquely connected to two second sleeves 120. Each chord main tube 111 is located directly above the midpoint of two adjacent web member connecting supports 10 in the same row. The two second sleeves 120 on the chord main tube 111 are screwed together with the opposite first sleeve 102 to form a truss web member 12. In this technical solution, the web member connecting supports 10 in the same row that are not on both sides are connected to two chord main tubes 111 connected by a chord connecting tube 112 through two truss web members 12 to form a triangular structure. The truss main tube 111, the two truss web members 12 connected to it, and the prefabricated composite floor slab 2 also form a triangular structure. The truss mesh 1 is stable and strong.

[0062] In another technical solution, two connecting rod sleeves 130 are fixed on both horizontal sides of the middle of the main tube 111 of the chord. The connecting rod sleeves 130 are provided with internal threads, and the two ends of the truss connecting rod 13 are provided with external threads. A truss connecting rod 13 is threaded between any two opposite connecting rod sleeves 130 of the same precast composite floor slab 2. The direction in which one end of the truss connecting rod 13 is screwed into one of the two opposite connecting rod sleeves 130 is opposite to the direction in which the other end is screwed into the other connecting rod sleeve 130. When installing the truss connecting rods 13 between the truss mesh panels 1, the truss mesh panels 1 are first installed by screwing the truss mesh panels 1 into the other connecting rod sleeves 130. One end of the connecting rod 13 is screwed into the bottom of all the connecting rod sleeves 130 on one of the truss mesh panels 1. Then, the opposite truss mesh panel 1 is placed in the design position. At this time, all the connecting rod sleeves 130 on the truss mesh panel 1 are aligned with the other end of the connecting rod 13. The truss connecting rod 13 is screwed in reverse one by one so that one end comes out of the connecting rod sleeve 130 and the other end is screwed into the connecting rod sleeve on the other truss mesh panel 1, thus completing the connection of the two truss mesh panels 1. Similarly, this operation is performed between two adjacent truss mesh panels 1 that do not belong to the same precast composite floor slab 2 during the hoisting process.

[0063] In another technical solution, the truss upper chord 11, truss web members 12, and truss connecting rods 13 are all steel tubular structures. Compared with smaller diameter rods, steel pipes have better bending and torsional resistance.

[0064] In another technical solution, the construction method of the above-mentioned truss-supported precast composite hollow floor slab includes the following steps:

[0065] S1. Based on the building's beam and column layout, on-site hoisting capacity, and stress calculation results, the dimensions of the precast composite floor slab 2 and precast beams 6 are designed. All components are processed in the precast component processing plant and then delivered to the construction site. Specifically, in the concrete component processing plant, the precast composite floor slab 2 is constructed according to the design dimensions and reinforcement scheme. After curing, it is delivered to the construction site. In the steel component processing plant, a laser cutting machine is used to cut commercial steel plates and steel pipes. The steel plates are processed into precast beams 6 and support fixing plates 101 that meet the dimensional requirements, and the steel pipes are processed into... The chord main tube 111, chord connecting tube 112, connecting rod sleeve 130, truss connecting rod 13, truss web member 12, first sleeve 102, and second sleeve 120 are made according to the required size and length. The internal and external thread sections of the above components are processed using tapping and threading equipment. The two second sleeves 120 and the two connecting rod sleeves 130 are welded to the same chord main tube 111 at the design angle. The two first sleeves 102 are welded to the support fixing plate 101 cut from finished steel plate to form the web member connecting support 10. After all components are processed, they are loaded onto a vehicle and sent to the construction site.

[0066] S2. At the construction site, according to the design requirements, the chord main tube 111 and the chord connecting tube 112 are sequentially and intermittently screwed to form a single integral truss upper chord 11 and temporarily supported. After the corresponding number of web member connecting supports 10 are placed in place, the corresponding number of truss web members 12 are connected between the web member connecting supports 10 and the truss upper chord 11 to form a truss mesh 1. Specifically, at the construction site, after the assembly of the truss upper chord 11 is completed, the corresponding number of truss web members 12 are screwed into the top of the second sleeve 120. Then, the truss upper chord 11 is supported by a bracket. After the corresponding number of web member connecting supports 10 are placed in place, the truss web members 12 are screwed in the opposite direction so that they partially come out of the second sleeve 120 and partially screwed into the first sleeve 102.

[0067] S3. Tighten the truss connecting rod 13 between several truss mesh pieces 1 belonging to the same precast composite floor slab 2, and then fix the bottom surface of the support fixing plate 101 to the precast composite floor slab 2. Specifically, first, tighten the truss connecting rod 13 to the connecting rod sleeve 130 on one of the truss mesh pieces 1 to the end, then place the other truss mesh piece 1 in place, and tighten the truss connecting rod 13 back to complete the connection of the two truss mesh pieces 1. Place the truss mesh piece 1 as a whole on the precast composite floor slab 2. The support fixing plate 101 can be fixed to the precast composite floor slab 2 by screws or adhesive.

[0068] S4. Hoist all precast beams 6 onto the fixed structural columns 7, and then hoist the precast composite floor slabs 2 in sequence and place them on the flange plates 61 of two adjacent precast beams 6 until all precast composite floor slabs 2 are hoisted. Specifically, the ends of the structural columns 7 are designed with node connections for the precast beams 6. The precast beams 6 can be fixed to the structural columns 7 by means of socket grouting, bolts or welding. After the precast beams 6 on the top floor are installed, the precast composite floor slabs 2 connected to the truss mesh 1 are hoisted one by one using on-site hoisting equipment, so that both short sides are placed on the flange plates 61. The long sides of the precast composite floor slabs 2 at the edges or special positions can also be placed on the flange plates 61.

[0069] S5. On the surface of the precast composite floor slab 2 between any two truss mesh panels 1, box-shaped core templates 3 are fixed in parallel at intervals. Specifically, the box-shaped core templates 3 are designed according to the dimensions of the concrete hidden beams 41 in the floor slab and are prefabricated in the factory or on the construction site. The box-shaped core templates 3 are placed between two truss mesh panels 1 of the same precast composite floor slab 2. The box-shaped core templates 3 can be installed and fixed before the precast composite floor slab 2 is hoisted, or they can be installed after the precast composite floor slab 2 is hoisted. After all the precast composite floor slabs 2 are hoisted, the box-shaped core templates 3 are fixed in parallel at intervals between two adjacent precast composite floor slabs 2. Between the truss mesh panels 1 of the precast composite floor slab 2, box-type core templates 31 are installed at the joints. The bottom of the box-type core templates 31 and the box-type core templates 31 at the joints are fixed to the precast composite floor slab 2 by bolts or adhesive to prevent displacement or floating during the pouring process. In addition to sealing the joints by filling with sponge strips or polyurethane coatings, optionally, in some structural designs with special requirements for the size and arrangement of concrete hidden beams 41, the shape of the box-type core templates 3 and the box-type core templates 31 at the joints also needs to be adjusted appropriately to avoid conflict and collision with the truss mesh panels 1.

[0070] S6. Fix the hidden beam reinforcement cage 51 in the space between any two rows of box core templates 3, then support the slab reinforcement 52 and run water and electricity pipes. Specifically, the hidden beam reinforcement cage 51 needs to be padded with pads and protective sleeves so that the hidden beam reinforcement cage 51 does not contact the box core template 3. The hidden beam reinforcement cage 51 and the web member connecting support 10 at the intersection position can be tied together. The hidden beam reinforcement cage 51 is continuous and both ends need to extend to the precast beam 6 and be connected to the precast beam 6 by means of bent anchor, sleeve, welding, etc., or holes are reserved on the precast beam 6 so that the hidden beam reinforcement cages 51 on both sides of the precast beam 6 can pass through and be connected. The slab reinforcement 52 is constructed synchronously with the water and electricity pipes. The connection method between the slab reinforcement 52 and the hidden beam reinforcement cage 51 and the precast beam 6 needs to be considered in the design.

[0071] S7. Seal the joints between any two adjacent precast composite floor slabs 2, seal the gaps between the box core template 3 and the upper surface of the precast composite floor slab 2, and pour the cast-in-place concrete layer 4. Specifically, after the construction of steel bars and water and electricity pipes on all precast composite floor slabs 2 is completed, use sponge strips and other sealing materials to seal the joint gaps below the precast composite floor slabs 2, and use polyurethane coating or other adhesive sealing materials to apply to the connection position between the web member connecting support 10 and the truss web member 12 to avoid concrete slurry contamination of the connection. Concrete pouring can only be carried out after the inspection is correct.

[0072] S8. Cure the cast-in-place concrete layer 4 until it reaches the design strength requirement. Then, remove all the upper chord members 11 and web members 12 of the truss. Fill the first sleeve 102 with grouting material to seal it and complete the floor construction. Specifically, before the strength of the cast-in-place concrete layer 4 reaches 75%, people are prohibited from walking on the floor. However, other construction processes can be carried out on the top floor. After the strength of the cast-in-place concrete layer 4 reaches 100%, people can walk on the floor to remove the upper chord members 11 and web members 12 of the truss. First, clean the sealing material at the connection between the web member connecting support 10 and the web member 12. Then, screw the web member 12 out of the first sleeve 102. After the removed components are lifted away, high-strength cement grout or other forms of grouting material are uniformly injected into the first sleeve 102 to seal it.

[0073] In this technical solution, all components are processed off-site. During the construction of the top-floor beams and columns, construction workers can simultaneously assemble the components in the component yard and fix the box core template 3 between two truss mesh panels 1 on the same precast composite floor slab 2 before hoisting. Only after the hoisting is correct can the construction of the box core template 31 at the joint, the on-site tied steel bars 5, and the water and electricity pipelines be carried out, which greatly saves on-site construction time. Moreover, after the concrete cast-in-place layer 4 reaches the demolding strength, the truss upper chord 11 and truss web members 12 are all removable and reusable components, which also reduces construction costs.

[0074] In another technical solution, in step S5, steel-adhesive is applied to the bottom surface of the support fixing plate 101 to fix it to the upper surface of the precast composite floor slab 2. In this technical solution, the main component of the steel-adhesive is a two-component bisphenol A modified epoxy resin structural adhesive (A and B), which can cure at room temperature with minimal shrinkage during the curing process. Before applying the steel-adhesive, the bottom surface of the support fixing plate 101 and the surface of the precast composite floor slab 2 at the bonding joint need to be cleaned with sandpaper and a spray bottle. Before the steel-adhesive cures, temporary auxiliary support needs to be provided for the truss mesh 1 to prevent shaking and affect the bonding effect.

[0075] In another technical solution, in step S7, the spacing between any two box-type core templates 3 is the same, so that the concrete hidden beams 41 form a dense ribbed beam network with consistent spacing and size.

[0076] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A truss-supported precast composite hollow floor slab, characterized in that, include: Several precast beams are parallel to each other and fixed to several completed structural columns; Several precast composite floor slabs are spliced ​​side by side, with the long side of each precast composite floor slab spliced ​​to the long side of other precast composite floor slabs. The two short sides of the bottom surface are placed on two parallel precast beams. At least two parallel truss meshes are fixed to the upper surface of the precast composite floor slabs. Each truss mesh includes a truss upper chord that is higher than the upper surface of the precast composite floor slab and parallel to the long side of the precast composite floor slab, several web member connecting supports, and several truss web members. Several web member connecting supports are fixed to the precast composite floor slabs in a row at intervals. Each web member connecting support is detachably fixed to the truss upper chord with one or more truss web members. Several truss connecting rods connect any two adjacent truss meshes. All the truss meshes and the precast composite floor slabs together form a truss load-bearing structure. Several box-shaped core templates are fixed to the upper surface of the precast composite floor slabs in a matrix. A cast-in-place concrete layer is formed above a precast composite floor slab. The cast-in-place concrete layer includes a hidden concrete beam cast within the box core formwork interval. The top surface of the cast-in-place concrete layer is higher than the top surface of the precast beam but not higher than the connection between the web member connecting support and the truss web member. The precast beam is a steel beam structure. The bottom surface of the precast beam extends to both sides with flange plates. Any two adjacent precast beams can support several precast composite floor slabs that are spliced ​​side by side. The web member connecting support includes a support fixing plate and two first sleeves. The support fixing plate is fixed to the upper surface of the precast composite floor slab. The two first sleeves are symmetrically welded to the support fixing plate. The truss upper chord includes several sets of downward-sloping second sleeves. The second sleeves and the first sleeves are coaxially opposite each other. The two ends of the truss web member are provided with external threads. The second sleeves and the first sleeves are provided with internal threads that match the truss web member. The two ends of the truss web member are matched and screwed into the corresponding second sleeves and first sleeves. When the truss web member is screwed to the top in the direction of the corresponding first sleeve or second sleeve, one end of the truss web member is in a disengaged state.

2. The truss-supported precast composite hollow floor slab as described in claim 1, characterized in that, The truss upper chord includes alternating threaded main chord tubes and chord connecting tubes. The two ends of the main chord tubes and chord connecting tubes are provided with matching threads. The middle of the main chord tube is connected to two second sleeves at an angle downwards. Each main chord tube is located directly above the midpoint of the connecting support of two adjacent web members in the same row. The two second sleeves on the main chord tube are screwed together with the opposite first sleeve to fit the truss web members.

3. The truss-supported precast composite hollow floor slab as described in claim 2, characterized in that, Two connecting rod sleeves are fixed on both horizontal sides of the middle of the main tube of the chord. The connecting rod sleeves are provided with internal threads, and the two ends of the truss connecting rod are provided with external threads. A truss connecting rod is threadedly connected between any two opposite connecting rod sleeves of the same precast composite floor slab.

4. The truss-supported precast composite hollow floor slab as described in claim 3, characterized in that, The truss upper chord, truss web members, and truss connecting rods are all steel tubular structures.

5. The construction method of the truss-supported precast composite hollow floor slab as described in claim 4, characterized in that, Includes the following steps: S1. Based on the beam and column layout of the building, the on-site hoisting capacity, and the stress calculation results, design the dimensions of the precast composite floor slabs and precast beams. After all components are processed in the precast component processing plant, they are sent to the construction site. S2. At the construction site, according to the design requirements, the main chord tube and the connecting tube of the chord are screwed in sequence at intervals to form a single integral truss upper chord and temporarily supported. After the corresponding number of web member connecting supports are placed in place, the corresponding number of truss web members are connected between the web member connecting supports and the truss upper chord to form a truss mesh. S3. Tighten the truss connecting rods between several truss meshes belonging to the same precast composite floor slab, and then fix the bottom surface of the support fixing plate to the precast composite floor slab. S4. Hoist all precast beams onto the fixed structural columns, then hoist the precast composite floor slabs in sequence and place them on the flanges of two adjacent precast beams until all precast composite floor slabs are hoisted. S5. On the surface of the precast composite floor slab between any two truss mesh panels, box-type core templates are fixed in parallel at intervals. S6. Fix the hidden beam reinforcement cage in the space between any two columns of box core formwork, then support the slab reinforcement and run water and electricity pipes. S7. Seal the joint between any two adjacent precast composite floor slabs, seal the gap between the box core formwork and the upper surface of the precast composite floor slab, and pour the cast-in-place concrete layer. S8. Cure the cast-in-place concrete layer until it reaches the design strength requirement, then remove all truss upper chords and truss web members, fill the first sleeve with grouting material to seal it, and complete the floor slab construction.

6. The construction method of the truss-supported precast composite hollow floor slab as described in claim 5, characterized in that, In step S5, steel-adhesive is applied to the bottom surface of the support fixing plate to fix it to the upper surface of the precast composite floor slab.

7. The construction method of the truss-supported precast composite hollow floor slab as described in claim 6, characterized in that, In step S7, the spacing between any two box-shaped core templates is the same.

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