Construction technology of large-span composite laminated floor

Abstract

The invention relates to a construction process for a large-span composite composite floor slab, which belongs to the field of building technology and comprises the following steps: casting a precast base plate, and embedding a plurality of steel connection boxes at equal intervals on both sides of the precast base plate along its length direction; when assembling the plurality of precast base plates along the transverse direction of the floor slab, the corresponding steel connection boxes on adjacent precast base plates abut against each other, and using bolt fasteners to fix and connect the two abutting steel connection boxes; laying a post-cast concrete composite layer steel mesh on the connected plurality of precast base plates and casting concrete; the invention utilizes steel connection boxes on both sides of the precast base plate, and bolt fasteners can be used to perform dry connection on the steel connection boxes on adjacent precast base plates; at the same time, the wet connection method of post-cast concrete ensures the continuity of the stress of the composite floor slab, and at the same time, there is no need to carry out a large amount of formwork support and steel bar binding work at the construction site, thereby improving the construction speed of the composite composite floor slab.

Description

Technical Field

[0001] The invention belongs to the technical field of construction, and in particular relates to a construction process for a large-span composite laminated floor. Background Art

[0002] As an important component of prefabricated concrete structure, large-span composite composite floor slab combines the advantages of traditional prefabricated floor slab and cast-in-place floor slab, and has high bearing capacity, good integrity and seismic performance. With the continuous promotion of prefabricated buildings in the field of civil construction in my country, large-span composite composite floor slabs have been studied and applied more and more widely.

[0003] The existing concrete large-span composite composite floor slab is composed of multiple prefabricated bottom plates spliced ​​horizontally along the floor slab, and then top steel bars are laid on them and a post-cast concrete layer is poured. Therefore, the force transmission performance of the joints between the prefabricated bottom plates is the key to ensuring whether the composite floor slab can bear bidirectional force. Because the prefabricated bottom plate is composed of a bottom plate steel mesh and concrete poured on the bottom plate steel mesh. The connection method for splicing prefabricated bottom plates in the prior art is: the internal stress-bearing steel bars are extended outward by a certain length on the side of the prefabricated bottom plate, and after the prefabricated bottom plate is hoisted to the specified position, a horizontal formwork is supported between adjacent prefabricated bottom plates, and the stress-bearing steel bars extending outward from the adjacent prefabricated bottom plates are tied and fixed at the same time, and then the tied and fixed stress-bearing steel bars are connected by pouring concrete, so that an integral wet connection seam is formed between adjacent prefabricated bottom plates.

[0004] However, this connection method requires a large amount of formwork support and steel bar binding work at the construction site, resulting in a low construction speed for large-span composite composite floors. Summary of the invention

[0005] In view of this, the present invention provides a construction process for a large-span composite composite floor slab, which can achieve reliable connection of prefabricated base plates without the need to carry out a large amount of formwork support and steel bar binding work at the construction site, so as to solve the shortcomings of the prior art.

[0006] The technical solution of the present invention is: a construction process of a large-span composite laminated floor, comprising the following steps:

[0007] S1. Casting the precast bottom plate: build a mold according to the size of the precast bottom plate, and cast ultra-high performance concrete in the mold to form the bottom lining plate. After the bottom lining plate reaches 100% strength, lay the bottom plate steel mesh on the top of the bottom lining plate, and then place multiple steel connection boxes at equal intervals on both sides of the top of the bottom lining plate along the length direction. Connect the steel connection boxes with the bottom plate steel mesh, and cast concrete on the bottom plate steel mesh to form the precast bottom plate. The steel connection boxes are flush with both sides of the precast bottom plate.

[0008] The bottom plate steel mesh includes: the inner lower stress-bearing steel bars of the longitudinal ribs and the inner lower stress-bearing steel bars of the transverse ribs, which are arranged at equal intervals in the longitudinal and transverse directions and connected to each other, and a steel connection box is fixed at the intersection of the inner lower stress-bearing steel bars of the longitudinal ribs and the inner lower stress-bearing steel bars of the bottom plate steel mesh, and the inner lower stress-bearing steel bars of the longitudinal ribs located at the outermost side of the bottom lining plate pass through the steel connection box, and the end of the inner lower stress-bearing steel bars of the transverse ribs is fixedly connected to one side of the steel connection box;

[0009] S2. When assembling multiple prefabricated bottom plates in the transverse direction of the floor slab, the corresponding steel connection boxes on the adjacent prefabricated bottom plates abut against each other, and the two abutting steel connection boxes are fixedly connected using bolt fasteners to connect the adjacent prefabricated bottom plates to each other;

[0010] S3. Laying a post-cast concrete laminated layer steel mesh on the connected multiple prefabricated bottom plates and pouring concrete, so that the multiple prefabricated bottom plates are connected into one body to form a large-span composite laminated floor.

[0011] Preferably, concrete is poured into the steel connection box, and the concrete is made of the same material as the bottom lining plate.

[0012] Preferably, the steel connecting box includes: a bottom steel plate, a side steel plate and bolts. The side steel plates are respectively fixed on the edges around the bottom steel plate. The side steel plates and the bottom steel plate are perpendicular to each other. The corresponding steel connecting boxes on adjacent prefabricated bottom plates abut against each other. The bolts are passed through the side steel plates of the two abutting steel connecting boxes, and the steel bars in the prefabricated bottom plate are connected to the side steel plates.

[0013] Preferably, a connecting hole is provided on the steel connecting box and is located on a side steel plate of the steel connecting box away from the prefabricated bottom plate, and a bolt passes through the connecting hole and is fixedly connected to the side steel plate.

[0014] Preferably, the connecting hole is a threaded hole and is threadably connected to the bolt.

[0015] Preferably, a plurality of circular holes for steel bars are provided on the steel connection box, and are respectively located on the side steel plates on both sides of the connection holes. The circular holes for steel bars on the two side steel plates are coaxially arranged in one-to-one correspondence, and the inner diameter of the circular holes for steel bars is 1 to 2 mm larger than the outer diameter of the steel bars in the prefabricated base plate.

[0016] Preferably, the steel connection box further comprises: an anchor bar, one end of which is fixedly connected to the side steel plate of the steel connection box away from the connection hole, and the other end of which extends into the prefabricated bottom plate.

[0017] Compared with the prior art, the present invention provides a construction process for a large-span composite composite floor slab. The construction process uses steel connection boxes set on both sides of the precast base plate. When the precast base plates are assembled, bolt fasteners are used to perform dry connection on the steel connection boxes on adjacent precast base plates, thereby achieving reliable connection of the precast base plates. Then, the post-cast concrete superimposed layer steel mesh is laid and concrete is poured to connect multiple precast base plates into one body to form a large-span composite composite floor slab. The post-cast concrete wet connection method ensures the continuity of the stress of the superimposed floor slab and the bidirectional stress performance of the superimposed floor slab. At the same time, it avoids setting a certain width of cast-in-place strips at the splicing parts of the precast base plates, and there is no need to carry out a large amount of formwork support and steel bar binding work at the construction site, thereby greatly improving the precast base plate connection and the construction speed of composite superimposed floors and prefabricated buildings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a three-dimensional diagram of the composite laminated floor slab of the present invention;

[0019] Figure 2 It is a layout diagram of the bottom plate steel mesh of the present invention;

[0020] Figure 3 is a half-section view of the composite composite floor slab of the present invention;

[0021] Figure 4 is an AA cross-sectional view of the present invention;

[0022] Figure 5 It is the BB cross-sectional view of the present invention;

[0023] Figure 6 It is an enlarged schematic diagram of point D of the present invention;

[0024] Figure 7 It is a CC cross-sectional view of the present invention;

[0025] Figure 8 It is an enlarged schematic diagram of point E of the present invention;

[0026] Fig. 9 is a perspective view of a steel connection box of the present invention;

[0027] Fig.10 It is a layout diagram of the post-cast concrete laminated layer steel mesh of the present invention. DETAILED DESCRIPTION

[0028] The present invention provides a construction process for a large-span composite laminated floor. Figures 1 to 10 The present invention is described with reference to the structural schematic diagram of FIG.

[0029] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings. These terms are only for the convenience of describing the technical solutions of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0030] As an important component of prefabricated concrete structure, composite composite floor slab combines the advantages of traditional prefabricated floor slab and cast-in-place floor slab, and has high bearing capacity, good integrity and seismic performance. Composite composite floor slab can be produced in a factory, automated and modular manner, and improve the overall prefabrication rate of prefabricated buildings. With the continuous promotion of prefabricated buildings in the field of civil construction in my country, composite composite floor slabs have been studied and applied more and more widely.

[0031] The existing concrete large-span composite composite floor slab is composed of multiple prefabricated bottom plates spliced ​​horizontally along the floor slab, and then top steel bars are laid on them and a post-cast concrete layer is poured. Therefore, the force transmission performance of the joints between the prefabricated bottom plates is the key to ensuring whether the composite floor slab can bear bidirectional force. Because the prefabricated bottom plate is composed of a bottom plate steel mesh and concrete poured on the bottom plate steel mesh. The connection method for splicing prefabricated bottom plates in the prior art is: the internal stress-bearing steel bars are extended outward by a certain length on the side of the prefabricated bottom plate, and after the prefabricated bottom plate is hoisted to the specified position, a horizontal formwork is supported between adjacent prefabricated bottom plates, and the stress-bearing steel bars extending outward from the adjacent prefabricated bottom plates are tied and fixed at the same time, and then the tied and fixed stress-bearing steel bars are connected by pouring concrete, so that an integral wet connection seam is formed between adjacent prefabricated bottom plates.

[0032] However, this connection method requires a large amount of formwork support and steel bar binding work at the construction site, resulting in a low construction speed for large-span composite composite floors.

[0033] Based on this, the present invention proposes a construction process for a large-span composite composite floor slab. The construction process uses steel connection boxes set on both sides of the precast base plate. When the precast base plates are assembled, bolt fasteners are used to perform dry connection of the steel connection boxes on adjacent precast base plates, thereby achieving reliable connection of the precast base plates. The post-cast concrete composite layer steel mesh is then laid and concrete is poured to connect multiple precast base plates into one to form a large-span composite composite floor slab. The post-cast concrete wet connection method ensures the continuity of the stress of the composite floor slab and the bidirectional stress performance of the formed composite floor slab. At the same time, it avoids setting a certain width of cast-in-place strip at the splicing part of the precast base plate, and there is no need to carry out a large amount of formwork support and steel bar binding work at the construction site, thereby greatly improving the precast base plate connection and the construction speed of composite composite floors and prefabricated buildings.

[0034] As shown in the figure, Figure 1 The following is a three-dimensional diagram of the composite composite floor slab of this embodiment. A construction process of a large-span composite composite floor slab includes the following steps:

[0035] S1. Casting the prefabricated bottom plate 5: building a mold according to the size of the prefabricated bottom plate 5, and casting ultra-high performance concrete in the mold to form the bottom lining plate 4. After the bottom lining plate 4 reaches 100% strength, laying a bottom plate steel mesh on the top of the bottom lining plate 4, placing a plurality of steel connection boxes 16 at equal intervals on both sides of the top of the bottom lining plate 4 along the length direction, connecting the steel connection boxes 16 with the bottom plate steel mesh, casting concrete on the bottom plate steel mesh to form the prefabricated bottom plate 5, and the steel connection boxes 16 are flush with both sides of the prefabricated bottom plate 5;

[0036] Figure 2 The bottom plate steel mesh arrangement diagram of this embodiment, wherein the bottom plate steel mesh comprises: lower stress-bearing steel bars 7 in longitudinal ribs and lower stress-bearing steel bars 9 in transverse ribs, which are arranged at equal intervals in the longitudinal and transverse directions and connected to each other, respectively, and a steel connection box 16 is fixed at the intersection of the lower stress-bearing steel bars 7 in the longitudinal ribs and the lower stress-bearing steel bars 9 in the transverse ribs of the bottom plate steel mesh, the lower stress-bearing steel bars 7 in the longitudinal ribs located at the outermost side of the bottom lining plate 4 pass through the steel connection box 16, and the end of the lower stress-bearing steel bars 9 in the transverse ribs is fixedly connected to one side of the steel connection box 16;

[0037] S2. When assembling a plurality of prefabricated bottom plates 5 in the transverse direction of the floor slab, the corresponding steel connection boxes 16 on the adjacent prefabricated bottom plates 5 abut against each other, and the two abutting steel connection boxes 16 are fixedly connected using bolt fasteners to connect the adjacent prefabricated bottom plates 5 to each other;

[0038] S3. Lay a post-cast concrete laminated layer steel mesh on the connected multiple prefabricated bottom plates 5 and pour concrete, so that the multiple prefabricated bottom plates 5 are connected into one body to form a large-span composite laminated floor.

[0039] Compared with the traditional wet connection of integral joints of composite floor slabs, the construction process disclosed in this embodiment: the use of a steel connection box can avoid the need to set a cast-in-place strip of a certain width at the splicing position, which requires a large amount of formwork support and steel bar binding work on the construction site, thereby greatly improving the industrial construction efficiency of prefabricated buildings.

[0040] Since the precast base plate concrete composite floor has a special structural form and stress characteristics, the dry connection of the precast base plate and the wet connection of the post-poured concrete layer adopted in this embodiment ensure the continuity of the stress of the concrete ribs in the precast base plate concrete composite floor. Compared with the traditional separate joint wet connection of the composite floor, the precast base plate in this embodiment ensures the bidirectional stress performance of the formed composite floor.

[0041] In this embodiment, the steel connection box 16 is connected to the bottom plate steel mesh during the casting process of the prefabricated bottom plate 5, so as to further enhance the connection strength between the steel connection box 16 and the prefabricated bottom plate 5 and improve the connection strength of adjacent prefabricated bottom plates 5.

[0042] In addition, in this embodiment, by setting a bottom lining plate 4 at the bottom of the precast base plate, ultra-high performance concrete can be used to improve the tensile strength of the precast base plate. At the same time, the steel connection box 16 is flush with the concrete on the top of the precast base plate 5, which facilitates the production of the precast base plate in the factory.

[0043] In this embodiment, the steel connection box 16 is fixed to the intersection of the lower stress-bearing steel bars 7 in the longitudinal ribs and the lower stress-bearing steel bars 9 in the transverse ribs of the bottom plate steel mesh, so as to improve the connection strength between the prefabricated bottom plate and the steel connection box 16.

[0044] As a further optimization solution, preferably, concrete is poured into the steel connection box 16 , and the concrete is made of the same material as the bottom lining plate 4 .

[0045] In this embodiment, by pouring UHPC material in the steel connection box 16 and utilizing the better tensile and compressive properties of the UHPC material, the two prefabricated bottom plates can be better connected, and together with the UHPC bottom lining plate 4, the bottom of the floor slab can withstand higher tension.

[0046] In the disclosed embodiment, the concrete in the steel connection box 16 is at the same height as the concrete in the prefabricated base plate 5 , which facilitates the insertion of pipelines on the prefabricated base plate and the tying of top steel bars.

[0047] As shown in the figure, Fig. 9This is a three-dimensional diagram of the steel connection box of this embodiment. Preferably, the steel connection box 16 includes: a bottom steel plate 23, a side steel plate 19 and bolts 18. The side steel plates 19 are respectively fixed on the edges around the bottom steel plate 23. The side steel plates 19 and the bottom steel plate 23 are perpendicular to each other. The corresponding steel connection boxes 16 on adjacent prefabricated bottom plates 5 abut against each other. The bolts 18 are passed through the side steel plates 19 of the two steel connection boxes 16 abutting against each other, and the steel bars in the prefabricated bottom plate 5 are connected to the side steel plates 19.

[0048] Preferably, a connection hole 20 (along the Y-axis direction) is opened on the steel connection box 16 and is located on the side steel plate 19 of the steel connection box 16 away from the prefabricated base plate 5 , and the bolt 18 passes through the connection hole 20 and is fixedly connected to the side steel plate 19 .

[0049] As a further optimization solution, in the embodiment of the present disclosure, preferably, the connecting hole 20 is a threaded hole and is threadably connected to the bolt 18 .

[0050] In this embodiment, the connection holes 20 are threaded holes, so that the bolts 18 can be threadedly connected to the two steel connection boxes 16 respectively, thereby further enhancing the connection strength of the adjacent steel connection boxes 16 .

[0051] As a further optimization solution, in the embodiment of the present disclosure, preferably, a plurality of steel bar circular holes 21 (such as Figure 1 As shown, along the X-axis direction), and respectively located on the side steel plates 19 on both sides of the connecting hole 20, the steel bar circular holes 21 on the two side steel plates 19 are coaxially arranged one by one, and the inner diameter of the steel bar circular hole 21 is 1 to 2 mm larger than the outer diameter of the steel bar in the prefabricated bottom plate 5.

[0052] In this embodiment, circular steel bar holes 21 are opened on the side steel plates 19 on both sides of the connecting hole 20. The inner diameter of the circular steel bar holes 21 is 1 to 2 mm larger than the outer diameter of the steel bars in the prefabricated bottom plate 5. This enables the steel bars in the prefabricated bottom plate 5 to pass through the steel connecting box 16 smoothly. While ensuring the force transmission performance of the steel connecting box 16 connected to the prefabricated bottom plate, the steel bars in the bottom plate steel mesh remain intact, further improving the bidirectional force-bearing performance of the composite floor slab.

[0053] As a further optimization solution, in the disclosed embodiment, preferably, the steel connection box 16 also includes: an anchor bar 17, one end of which is fixedly connected to the side steel plate 19 of the steel connection box 16 away from the connection hole 20, and the other end extends into the prefabricated base plate 5.

[0054] In this embodiment, the anchor bar 17 can enhance the stability of the connection between the steel connection and the prefabricated base plate, and further enhance the force-bearing and force-transmitting performance of the prefabricated base plate. The anchor bar 17 is located in the middle of the side steel plate 19, so that the anchor bar 17 is located in the transverse rib of the prefabricated base plate, further improving the stability of the connection between the steel connection box and the prefabricated base plate.

[0055] The post-cast concrete composite layer steel bars in the disclosed embodiment include: upper stress-bearing steel bars 6 in the longitudinal ribs and upper stress-bearing steel bars 8 in the transverse ribs. The upper stress-bearing steel bars 6 in the longitudinal ribs and the upper stress-bearing steel bars 8 in the transverse ribs are respectively located directly above the lower stress-bearing steel bars 7 in the longitudinal ribs and the lower stress-bearing steel bars 9 in the transverse ribs.

[0056] The bottom plate steel mesh and the post-cast concrete superimposed layer steel bars use stirrups to form a reinforcement cage, wherein the stirrups include stirrups 12 inside the longitudinal ribs and stirrups 13 inside the transverse ribs, as shown in the figure. Fig.10 This is the reinforcement arrangement diagram for the post-cast concrete superposition layer. Figure 5 It is the BB cross-sectional view of this embodiment, the upper stress-bearing steel bars 6 and the lower stress-bearing steel bars 7 in the longitudinal ribs are inserted into the stirrups 12 in the longitudinal ribs perpendicularly thereto and are connected to each other, the upper stress-bearing steel bars 8 and the lower stress-bearing steel bars 9 in the transverse ribs are inserted into the stirrups 13 in the transverse ribs perpendicularly thereto and are connected to each other.

[0057] The post-cast concrete composite layer reinforcement also includes: longitudinal stress-bearing reinforcement 10 at the top of the post-cast concrete composite layer and transverse stress-bearing reinforcement 11 at the top of the post-cast concrete composite layer. The longitudinal stress-bearing reinforcement 10 at the top of the post-cast concrete composite layer and the transverse stress-bearing reinforcement 11 at the top of the post-cast concrete composite layer are respectively arranged longitudinally and transversely directly above the lightweight filling body 3. The longitudinal stress-bearing reinforcement 10 at the top of the post-cast concrete composite layer and the transverse stress-bearing reinforcement 11 at the top of the post-cast concrete composite layer are connected to the upper stress-bearing reinforcement 6 inside the longitudinal rib and the upper stress-bearing reinforcement 8 inside the transverse rib.

[0058] The composite composite floor disclosed in this embodiment is a method for connecting the plates in low-rise and multi-story medium- and large-span composite floors, including three parts: a steel connection box 16, a box-type bolt connection technology between prefabricated bottom plates, and a wet connection technology between post-cast concrete composite layers. The details are as follows:

[0059] 1. Steel connection box 16

[0060] The steel connection box 16 embedded in the prefabricated bottom plate 5 is composed of: a bottom steel plate 23 (placed directly on the top of the UHPC liner), four steel plates 19 around it (including an open steel plate for bolt connection, and because the lower stress-bearing steel bars in the longitudinal ribs need to pass through, it is necessary to open steel bar through-holes 21 at designated positions of the two steel plates 19 on both sides of the connection hole 20; the other steel plates 19 are welded to the lower stress-bearing steel bars 9 in the transverse ribs).

[0061] 2. Cassette bolt connection technology

[0062] According to the previous test research, this type of composite floor is mainly stressed by the longitudinal and transverse ribs and the top concrete between the ribs under the vertical load. In order to facilitate the dry connection technology of the precast base plate, the steel connection box 16 is embedded in the precast base plate and located at the intersection of the reinforced concrete longitudinal rib 1 and the reinforced concrete transverse rib 2. The anchor bar 17 is inserted into the stirrup 13 inside the transverse rib, so that the anchor bar 17 is connected to the reinforced concrete transverse rib 2 of the precast base plate, further enhancing the strength of the connection between the steel connection box 16 and the precast base plate.

[0063] At the construction site, after the adjacent prefabricated bottom plates with embedded steel connection boxes 16 are hoisted to the designated position, the two adjacent prefabricated bottom plates are connected by inserting high-strength bolts into the steel connection boxes 16. After the high-strength bolts are tightened, the same UHPC material as the bottom liner is poured into the steel connection box 16 to the top of the steel connection box 16.

[0064] 3. Wet connection technology between post-cast concrete laminated slabs:

[0065] After the UHPC material cast in the steel connection box 16 reaches the design strength, the post-cast concrete superposition layer steel mesh is tied and laid, and the box bolts of the cast UHPC are cast together with the top of the precast bottom plate by pouring concrete, so that the entire plate forms a bidirectionally stressed composite composite floor.

[0066] The specific construction steps of the large-span composite building in the above embodiment are:

[0067] Step 1: Prefabricated base plate production and steel connection box 16 embedded

[0068] Clean and clear the steel structure mold; support the side steel formwork according to the width and length of the UHPC liner (the thickness of the UHPC liner is 20mm); apply concrete release agent; after all the work is confirmed to be correct, pour the prepared UHPC material; use a wooden sawtooth brush to artificially roughen the surface of the exposed UHPC material to meet the rough surface requirement of "concave and convex surface difference ≥ 4mm" stipulated in Article 9.5.2 of the "Concrete Structure Design Code";

[0069] After the UHPC material of the bottom liner reaches 100% strength, place the side formwork of the prefabricated bottom slab around it according to the design dimensions on the drawing, and apply concrete release agent inside it; as shown in the figure, Figure 3 is a half-section view of the composite composite floor slab of this embodiment, Figure 4 The AA cross-sectional view of this embodiment shows that the lightweight filling body 3 (autoclaved aerated concrete block) after being soaked for 24 hours is placed in the designated design position (the bottom of the aerated block is bonded to the UHPC with a 5m thick bonding mortar), as shown in the figure. Figure 7The CC cross-sectional view of this embodiment is shown, and the lightweight filling body 3 is tapped lightly with a rubber hammer to keep the top surface height consistent; Figure 8 This is an enlarged schematic diagram of the E of this embodiment, and then the pre-processed steel connection box 16 is placed in the designated position (and the inside of the box is temporarily filled with lightweight materials such as EPS to avoid pouring concrete); in the gap area between the lightweight filling bodies 3, a pre-tied steel cage (including: the lower stress steel bars 7 in the longitudinal ribs, the lower stress steel bars 9 in the transverse ribs and stirrups are connected, and the stirrups are abutted against the lightweight filling body 3), wherein the lower stress steel bars 7 in the longitudinal ribs pass through the steel bar circular holes 21, and the lower stress steel bars 9 in the transverse ribs are welded and fixed to the side steel plates 19;

[0070] After the above confirmation, pour 80mm thick C30 grade concrete; after the concrete has initially set, use a wooden sawtooth brush to artificially roughen the exposed concrete surface to meet the rough surface requirement of "difference between concave and convex surfaces ≥ 4mm" stipulated in Article 9.5.2 of the "Code for Design of Concrete Structures".

[0071] Step 2: Dry bolt connection

[0072] After the prefabricated base plate is hoisted to the installation position, the EPS material filled in the steel connection box 16 in the prefabricated base plate is taken out; as shown in the figure, Figure 6 This is an enlarged schematic diagram of point D of this embodiment. Matching bolts are inserted into the connection holes in the steel connection box 16 in the prefabricated base plate, and bolt connections are made using gaskets and nuts. After the above bolts are tightened, the same UHPC material as the bottom liner is poured in the steel connection box 16 (the pouring height is the same as the height of the steel connection box 16).

[0073] Step 3: Wet connection of post-cast concrete layer

[0074] After the UHPC in the steel connection box 16 in "Step 2" reaches the design strength, the precast base plate and the top surface of the concrete in the steel connection box 16 constitute the superposition surface 15, and the post-cast concrete superposition layer steel bars are laid on the superposition surface 15. After confirmation, concrete is poured on the precast base plate to form the post-cast superposition layer 14. After the top post-cast concrete superposition layer reaches the design strength, a precast base plate concrete superposition floor slab based on a hybrid connection with bidirectional force is formed.

[0075] The above disclosure is only a preferred specific embodiment of the present invention, but the embodiments of the present invention are not limited thereto, and any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A construction process for a large-span composite laminated floor, characterized in that: The following steps are involved: S1, casting the prefabricated bottom plate (5): constructing a mold according to the size of the prefabricated bottom plate (5), and casting ultra-high performance concrete in the mold to form a bottom lining plate (4), after the bottom lining plate (4) reaches 100% strength, laying a bottom plate steel mesh on the top of the bottom lining plate (4), placing a plurality of steel connection boxes (16) at equal intervals on both sides of the top of the bottom lining plate (4) along the length direction, connecting the steel connection boxes (16) to the bottom plate steel mesh, and casting concrete on the bottom plate steel mesh to form the prefabricated bottom plate (5), and the steel connection boxes (16) are flush with both sides of the prefabricated bottom plate (5); The bottom plate steel mesh comprises: lower stress-bearing steel bars (7) in the longitudinal ribs and lower stress-bearing steel bars (9) in the transverse ribs, wherein the lower stress-bearing steel bars (7) in the longitudinal ribs and the lower stress-bearing steel bars (9) in the transverse ribs are arranged at equal intervals in the longitudinal and transverse directions and are connected to each other, a steel connection box (16) is fixed at the intersection of the lower stress-bearing steel bars (7) in the longitudinal ribs and the lower stress-bearing steel bars (9) in the transverse ribs of the bottom plate steel mesh, the lower stress-bearing steel bars (7) in the longitudinal ribs located at the outermost side of the bottom lining plate (4) pass through the steel connection box (16), and the end of the lower stress-bearing steel bars (9) in the transverse ribs is fixedly connected to one side of the steel connection box (16); S2, when assembling the plurality of prefabricated bottom plates (5) in the transverse direction of the floor slab, the corresponding steel connection boxes (16) on the adjacent prefabricated bottom plates (5) abut against each other, and using bolt fasteners to fix the two abutting steel connection boxes (16) to connect the adjacent prefabricated bottom plates (5) to each other; S3, laying a post-cast concrete laminated layer steel mesh on the connected multiple prefabricated bottom plates (5) and pouring concrete, so that the multiple prefabricated bottom plates (5) are connected into one body to form a large-span composite laminated floor; Concrete is poured in the steel connection box (16), and the concrete is made of the same material as the bottom lining plate (4); The steel connection box (16) comprises: a bottom steel plate (23), a side steel plate (19) and a bolt (18); the side steel plates (19) are respectively fixed to the edges around the bottom steel plate (23); the side steel plates (19) and the bottom steel plate (23) are perpendicular to each other; the corresponding steel connection boxes (16) on adjacent prefabricated bottom plates (5) abut against each other; the bolt (18) is passed through the side steel plates (19) of the two abutting steel connection boxes (16); the steel bars in the prefabricated bottom plate (5) are connected to the side steel plates (19); the steel connection box (16) is provided with a connection hole (20) and is located on the side steel plate (19) of the steel connection box (16) away from the prefabricated bottom plate (5); The steel connection box (16) is provided with a plurality of steel bar circular holes (21), which are respectively located on the side steel plates (19) on both sides of the connection hole (20), the steel bar circular holes (21) on the two side steel plates (19) are coaxially arranged in a one-to-one correspondence, and the inner diameter of the steel bar circular hole (21) is 1 to 2 mm larger than the outer diameter of the steel bar in the prefabricated bottom plate (5); The post-cast concrete superimposed layer reinforcement includes: upper stress-bearing reinforcement (6) in the longitudinal ribs and upper stress-bearing reinforcement (8) in the transverse ribs, wherein the upper stress-bearing reinforcement (6) in the longitudinal ribs and the upper stress-bearing reinforcement (8) in the transverse ribs are respectively located directly above the lower stress-bearing reinforcement (7) in the longitudinal ribs and the lower stress-bearing reinforcement (9) in the transverse ribs; The post-cast concrete superimposed layer reinforcement also includes: a post-cast concrete superimposed layer top longitudinal stress-bearing reinforcement (10), a post-cast concrete superimposed layer top transverse stress-bearing reinforcement (11), the post-cast concrete superimposed layer top longitudinal stress-bearing reinforcement (10), and the post-cast concrete superimposed layer top transverse stress-bearing reinforcement (11) are respectively arranged longitudinally and transversely directly above the lightweight filling body (3), and the post-cast concrete superimposed layer top longitudinal stress-bearing reinforcement (10), and the post-cast concrete superimposed layer top transverse stress-bearing reinforcement (11) are connected to the longitudinal rib inner upper stress-bearing reinforcement (6), and the transverse rib inner upper stress-bearing reinforcement (8); The steel connection box (16) further comprises an anchor bar (17), one end of the anchor bar (17) being fixedly connected to a side steel plate (19) of the steel connection box (16) away from the connection hole (20), and the other end of the anchor bar (17) extending into the prefabricated bottom plate (5), the anchor bar (17) being located in the middle of the side steel plate (19).

2. The construction process of a large-span composite composite floor slab according to claim 1, characterized in that: The bolt (18) passes through the connection hole (20) and is fixedly connected to the side steel plate (19).

3. The construction process of a large-span composite composite floor slab according to claim 2, characterized in that: The connection hole (20) is a threaded hole and is threadably connected to the bolt (18).

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