UHPC (Ultra High Performance Concrete)-based steel bar truss floor node structure and use method

Abstract

The invention discloses a UHPC-based steel bar truss floor node structure and a using method, and belongs to the technical field of building structures. The UHPC-based steel bar truss floor node structure comprises a steel bar truss prefabricated floor, a shear wall body and a supporting device; the steel bar truss prefabricated floor slab is fixed to the upper portion of the supporting device, one end of the steel bar truss prefabricated floor slab is UHPC, and the other end of the steel bar truss prefabricated floor slab is a common concrete cast-in-place layer. The steel bar truss prefabricated floor slab comprises prefabricated layer concrete, lower steel bars are arranged on the upper portion of the prefabricated layer concrete, upper steel bars are arranged on the upper portions of the lower steel bars, and a plurality of truss diagonal web bars are arranged between the upper steel bars and the lower steel bars at intervals. The fabricated steel bar truss floor can solve the problem that a wet joint for connecting a steel bar truss floor and a wall is too long, is suitable for the construction logic of a nuclear power station open-top method, and can improve the mounting precision of large-diameter steel bars, embedded parts and penetrating parts by adopting the fabricated steel bar truss floor.

Description

Technical Field

[0001] The invention belongs to the technical field of building structures, and in particular relates to a UHPC-based steel truss floor node structure and a use method. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Nuclear power plants mainly use cast-in-place slabs as the main floor form. Due to the large earthquake effects, accident temperature loads and equipment loads that the third-generation nuclear power plant design bears, the designed floor thickness is large, and the number of steel bars selected is large and the diameter is large. Therefore, if the positioning and binding of steel bars are completely completed by manpower, the construction intensity is high, the safety risk is high, the construction efficiency is low and the working hours are long. Due to the large diameter of the main reinforcement, it is extremely difficult to bend and adjust the steel bars on site, the spacing of the steel bars is difficult to control, the positioning accuracy is poor, and the binding quality and consistency are difficult to ensure. In addition, large embedded parts and large-diameter penetration parts are often arranged on the floor of nuclear power plants. If the positioning accuracy of the floor reinforcement is poor, it will cause the embedded anchor bars and penetration parts to collide with the steel bars and be difficult to install, which greatly increases the construction difficulty and reduces the installation quality of the embedded parts and penetration parts. Therefore, prefabricated floor slabs have significant advantages in nuclear power plants, but the prefabricated part of the prefabricated floor slab currently used is only used as a casting template, which increases the dead weight and still relies on manual binding of steel bars.

[0004] Reinforced truss composite slabs have been widely used in the field of civil construction. The connection of reinforced truss composite slabs mainly adopts post-cast integral connection (wet joint). Due to the large diameter of the steel bars in the nuclear power plant floor slab, when conventional concrete is used as the connection material, according to the existing standard system, the lap length of the steel bars reaches about 40d, and the span of the connection part reaches more than 1m, which increases the difficulty of design, production, transportation and construction. Combined with the open-top construction method often used in nuclear power plants, shear walls are often cast before floor slabs. Therefore, the node connection form commonly used in the reinforced truss concrete floor atlas (22G522-1) is no longer applicable.

[0005] At present, there are few studies and patents on the connection nodes of reinforced truss floor slabs and walls suitable for nuclear power plants. Patent publication number CN213087172U proposes a reinforced concrete floor slab and its connection node. By setting steel strand anchors in the prefabricated layer, the problem of reducing the effective height of the plate end by connecting the lower steel bars of the prefabricated truss reinforced concrete composite floor slab with additional steel bars is solved. However, this method requires the post-cast concrete to be cast together with the wall slab node, so this patent cannot be applied to the construction method of pre-embedded sleeves in shear walls constructed by the open top method. Application publication number CN115012580A proposes an assembled integral reinforced concrete structure. This method connects the longitudinal force-bearing steel bars of the prefabricated plate and the shear wall in the node area by extrusion sleeves and threaded sleeves. Although the use of extrusion sleeves instead of grouting sleeves solves the problem of the difficulty in ensuring the construction quality of the grouting sleeves, it still does not solve the problem of the large diameter of the steel bar and the excessive length of the post-casting section. Moreover, if the beard bar is reserved, it will affect the hoisting operation of the equipment during the open top method construction. Authorization announcement number CN209099602U proposed a UHPC ultra-high performance concrete bottom detachable steel truss floor formwork, and application publication number CN115387522A proposed an ultra-thin high-performance concrete bottom plate assembled steel truss floor. These two patented methods use ultra-high performance concrete in the prefabricated floor layer, which reduces the thickness of the prefabricated floor layer and reduces the deadweight of the structure, but still fails to solve many difficulties at the slab-wall connection nodes.

[0006] In view of the various difficulties in the open-top construction of prefabricated reinforced truss floors in nuclear power plants, it is necessary to study the slab-wall connection nodes and corresponding construction methods suitable for nuclear power plants, improve the current cast-in-place slab form that relies on manual binding of steel bars, and improve the connection length of wet joints to meet the open-top construction method of nuclear power plants. Summary of the invention

[0007] In view of the above problems, the present invention provides a UHPC-based steel truss floor node structure and use method, which can solve the problem of too long wet joint length of the steel truss floor wall connection, and is suitable for the construction logic of the open-top method of nuclear power plants. The assembled steel truss floor can improve the installation accuracy of large-diameter steel bars, embedded parts, and through-pieces.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A UHPC-based steel truss floor node structure, comprising a steel truss prefabricated floor, a shear wall and a support device; the steel truss prefabricated floor is fixed to the upper part of the support device, one end of the steel truss prefabricated floor is UHPC concrete, and the other end of the steel truss prefabricated floor is a common concrete cast-in-place layer;

[0010] The steel bar truss prefabricated floor comprises a prefabricated layer of concrete, lower steel bars are arranged on the upper part of the prefabricated layer of concrete, upper steel bars are arranged on the upper part of the lower steel bars, and a plurality of truss diagonal web bars are arranged between the upper steel bars and the lower steel bars.

[0011] Furthermore, the lower steel bars include lower transverse steel bars and lower longitudinal steel bars, and a plurality of the lower transverse steel bars and lower longitudinal steel bars are provided, and the plurality of lower transverse steel bars and lower longitudinal steel bars are arranged in a staggered manner.

[0012] Furthermore, the upper steel bars include upper transverse steel bars and upper longitudinal steel bars, and a plurality of the upper transverse steel bars and upper longitudinal steel bars are provided, and the plurality of upper transverse steel bars and upper longitudinal steel bars are arranged in a staggered manner.

[0013] Furthermore, a plurality of wall reinforcements are arranged at intervals inside the shear wall, a plurality of reinforcement sleeves are embedded in the shear wall, and the wall reinforcements pass through the reinforcement sleeves and are connected to the upper longitudinal reinforcements of the upper reinforcements and the lower longitudinal reinforcements of the lower reinforcements.

[0014] Furthermore, a template or a steel mesh is provided on the side of the prefabricated steel truss floor slab, and the template or the steel mesh is installed on the side of the prefabricated steel truss floor slab before concrete pouring.

[0015] Further, the support device is a combination of embedded parts and angle steel, or I-beam, or UHPC bracket;

[0016] The embedded parts are embedded in the shear wall, the upper end surface of the angle steel supports the prefabricated floor slab of the steel bar truss, and the side surface of the angle steel is connected to the embedded parts.

[0017] Furthermore, the upper end surface of the I-beam supports the prefabricated steel truss floor slab; the upper end surface of the UHPC corbel supports the prefabricated steel truss floor slab, the side surface of the UHPC corbel is connected to the shear wall body, and the UHPC corbel is cast by UHPC concrete.

[0018] A method for using a UHPC-based steel truss floor node structure comprises the following steps:

[0019] Step 1: Tie up the wall reinforcement and the reinforcement and reinforcement sleeves reserved in the wall and connected to the floor slab, and install a support device at one end of the wall reinforcement;

[0020] Step 2: pouring concrete to the position of the wall reinforcement and curing the poured concrete to a specified strength, thus forming a shear wall;

[0021] Step 3: Tie the lower longitudinal steel bars, the lower transverse steel bars, and the truss diagonal web bars, and install them on the upper part of the precast concrete layer after the tying is completed. After the installation is completed, hoist the entire structure to one end of the shear wall;

[0022] Step 4: Install the upper longitudinal steel bars and lower longitudinal steel bars at the slab wall connection nodes, and tie the upper longitudinal steel bars and upper transverse steel bars of the floor slab at the same time;

[0023] Step 5: Support the side formwork or steel mesh, pour the UHPC concrete in the overlap area, and cure it to the specified strength;

[0024] Step 6. Remove the side formwork or steel mesh, pour ordinary concrete in the remaining areas, and cure to the specified strength.

[0025] Furthermore, the supporting device is a temporary supporting structure or a permanent supporting structure, the temporary supporting structure is an I-beam or a UHPC corbel, and the permanent supporting structure is a combination of embedded parts and angle steels.

[0026] Furthermore, the lap length of the upper longitudinal steel bars and the upper transverse steel bars is 13d, where d represents the diameter of the upper transverse steel bars; and the pouring thickness of the precast layer concrete is 10-15mm.

[0027] Compared with the prior art, the present invention has the following advantages and positive effects:

[0028] The present invention reduces the requirement for the connection length of the wet joint of the steel truss floor slab to the maximum by pouring UHPC concrete at the connection between the steel truss floor slab and the wall, and realizes the effective anchoring and force transmission function of the longitudinal steel bars within the minimum wet joint length.

[0029] The prefabricated steel truss floor of the present invention can be used as a template for the upper floor slab, breaking through the traditional way of erecting scaffolding to support the formwork, avoiding the impact and interference on the construction activities of the lower part of the floor slab. During the construction of the upper floor slab, the installation and other operations in the lower space can be carried out normally, realizing the parallel construction of the upper and lower floors, greatly improving the construction efficiency. The present invention reserves steel sleeves on the wall and sets different supporting devices, which can meet various complex and diverse application scenarios and is suitable for the construction logic of the open top method. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0031] Figure 1 Schematic diagram of the steel truss floor node structure in Example 1 of the present invention Figure 1 ;

[0032] Figure 2 is a schematic elevation view of a steel truss floor node structure in Example 1 of the present invention;

[0033] Figure 3 Schematic diagram of the steel truss floor node structure in Example 1 of the present invention Figure 2 ;

[0034] Figure 4 Schematic diagram of the steel truss floor node structure in Example 1 of the present invention Figure 3 ;

[0035] In the figure: 1. Lower longitudinal reinforcement; 2. Upper longitudinal reinforcement; 3. Truss diagonal web reinforcement; 4. Lower transverse reinforcement; 5. Upper transverse reinforcement; 6. Precast layer concrete; 7. UHPC concrete; 8. Ordinary concrete cast-in-place layer; 9. Rebar sleeve; 10. Angle steel; 11. Embedded parts; 12. Shear wall; 13. Formwork; 14. I-beam; 15. UHPC corbel; 16. Wall reinforcement. DETAILED DESCRIPTION

[0036] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0037] In view of the various difficulties in the open-top construction of prefabricated reinforced truss floors in nuclear power plants, it is necessary to study the slab-wall connection nodes and corresponding construction methods suitable for nuclear power plants, and improve the current cast-in-place slab form that relies on manual binding of steel bars into prefabricated reinforced truss floors, and reduce the connection length of wet joints to meet the construction method of the open-top method of nuclear power plants.

[0038] Embodiment 1:

[0039] The present invention is described in detail below in conjunction with the accompanying drawings. This embodiment discloses a UHPC-based steel truss floor node structure, such as Figure 1 As shown, it includes a steel truss prefabricated floor, a shear wall 12 and a supporting device; the steel truss prefabricated floor is fixed to the upper part of the supporting device, one end of the steel truss prefabricated floor is UHPC concrete 7, and the other end of the steel truss prefabricated floor is a common concrete cast-in-place layer 8;

[0040] The steel bar truss prefabricated floor comprises a prefabricated concrete layer 6, lower steel bars are arranged on the upper part of the prefabricated concrete layer 6, upper steel bars are arranged on the upper part of the lower steel bars, and a plurality of truss diagonal web bars 3 are arranged between the upper steel bars and the lower steel bars.

[0041] The prefabricated steel truss floor slab can be used as the formwork for the upper floor slab13, breaking through the traditional method of erecting scaffolding to support the formwork, avoiding the impact and interference on the construction activities under the floor slab. During the construction of the upper floor slab, the installation and other operations in the lower space can proceed normally, realizing the parallel construction of the upper and lower floors, greatly improving the construction efficiency.

[0042] The lower reinforcement includes a lower transverse reinforcement 4 and a lower longitudinal reinforcement 1. A plurality of lower transverse reinforcements 4 and lower longitudinal reinforcements 1 are provided, and a plurality of lower transverse reinforcements 4 and lower longitudinal reinforcements 1 are arranged alternately. The upper reinforcement includes an upper transverse reinforcement 5 and an upper longitudinal reinforcement 2. A plurality of upper transverse reinforcements 5 and upper longitudinal reinforcements 2 are provided, and a plurality of upper transverse reinforcements 5 and upper longitudinal reinforcements 2 are arranged alternately.

[0043] like Figure 2 As shown, a plurality of wall reinforcements 16 are arranged at intervals inside the shear wall 12. The wall reinforcements 16 pass through the reinforcement sleeve 9 and are connected to the upper longitudinal reinforcements 2 of the upper reinforcements and the lower longitudinal reinforcements 1 of the lower reinforcements. The wall reinforcements 16 are bent structures, and the bent structure of the wall reinforcements 16 can ensure the overall connection strength.

[0044] The steel sleeve 9 is embedded in the shear wall 12. After the steel sleeve 9 is cast, one end of the steel sleeve 9 faces the outside of the shear wall 12, and the steel sleeve 9 and the wall steel bars 16 are connected with the steel bars of the steel truss prefabricated floor slab, that is, the steel truss prefabricated floor slab is connected to the shear wall 12 through the wall steel bars 16 and the steel sleeve 9.

[0045] A template 13 or a steel mesh is set on the side of the precast steel truss slab. The template 13 or the steel mesh is installed on the side of the precast steel truss slab before concrete pouring. The template 13 structure is a model for the newly cast concrete structure or component, so that the hardened concrete has the shape and size required by the design. The function is to ensure the shape and position of the template 13 and bear the weight of the template 13 and the newly cast concrete as well as the construction load. The template 13 structure is a temporary structure used in the construction of reinforced concrete projects. It has a great impact on the construction quality and project cost of reinforced concrete projects. The template 13 or the steel mesh is set so that the precast steel truss slab can be cast and formed according to the specified size.

[0046] The supporting device is a combination of embedded parts 11 and angle steel 10. The embedded parts 11 are embedded in the shear wall 12. The upper end surface of the angle steel 10 supports the prefabricated steel truss floor slab. The side of the angle steel 10 is connected to the embedded parts 11. The embedded parts 11 are installed on the wall reinforcement 16 before the shear wall 12 is cast. After the shear wall 12 is cast, the side of the embedded parts 11 is outside the shear wall 12, and its side is connected to the side of the angle steel 10, so as to cooperate with the angle steel 10 to support the prefabricated steel truss floor slab and ensure the stability of the installation of the prefabricated steel truss floor slab.

[0047] like Figure 3 As shown, the supporting device is an I-beam 14, and the upper end surface of the I-beam 14 supports the prefabricated steel truss floor slab; the I-beam 14 is a temporary supporting structure, which supports the prefabricated steel truss floor slab through the upper end surface of the I-beam 14 to ensure the stability of the installation of the prefabricated steel truss floor slab.

[0048] like Figure 4 As shown, the supporting device is a UHPC corbel 15, the upper end surface of the UHPC corbel 15 supports the prefabricated steel truss floor slab, the side surface of the UHPC corbel 15 is connected to the shear wall 12, and the UHPC corbel 15 is cast and formed by UHPC concrete 7. The UHPC corbel 15 is a temporary supporting structure, which supports the prefabricated steel truss floor slab through the upper end surface of the UHPC corbel 15 to ensure the stability of the installation of the prefabricated steel truss floor slab.

[0049] Embodiment 2:

[0050] A method for using a UHPC-based steel truss floor node structure comprises the following steps:

[0051] Step 1: Tie up the wall reinforcement 16 and the reinforcement and reinforcement sleeve 9 reserved in the wall and connected to the floor slab, and install a support device at one end of the wall reinforcement 16;

[0052] Step 2: pouring concrete to the position of the wall reinforcement 16, and curing the poured concrete to a specified strength, so as to form a shear wall 12;

[0053] Step three, tie the lower longitudinal steel bars 1, the lower transverse steel bars 4, and the truss diagonal web bars 3, and after tying, install them on the upper part of the prefabricated layer of concrete 6. After installation, hoist them as a whole to one end of the shear wall 12; that is, hoist and fix the prefabricated steel truss floor (with the lower longitudinal steel bars 1, the truss diagonal web bars 3, and the lower transverse steel bars 4).

[0054] Step 4: Install the upper longitudinal steel bars 2 and the lower longitudinal steel bars 1 at the connection nodes of the slab walls, and tie the upper longitudinal steel bars 2 and the upper transverse steel bars 5 of the floor slab at the same time;

[0055] Step 5: Support the side formwork 13 or steel mesh, pour the UHPC concrete 7 in the overlap area, and cure it to the specified strength; the formwork 13 or steel mesh is used to ensure that the prefabricated steel truss floor is cast according to the set size, and the UHPC concrete 7 is poured at the position of the slab wall connection node. After pouring, it is cured to ensure the overall strength.

[0056] The use of cast UHPC concrete 7 minimizes the connection length requirement of the wet joints of the steel truss slabs, and achieves effective anchoring and force transmission functions of the longitudinal steel bars within the minimum wet joint length.

[0057] Step 6: Remove the side formwork 13 or the steel mesh, pour ordinary concrete in the remaining area, and cure to the specified strength. After removing the side formwork 13 or the steel mesh, pour ordinary concrete in the remaining area to form an ordinary concrete cast-in-place layer 8.

[0058] The supporting device is a temporary supporting structure or a permanent supporting structure, the temporary supporting structure is an I-beam 14 or a UHPC bracket 15, and the permanent supporting structure is a combination of an embedded part 11 and an angle steel 10. Various complex and diverse application scenarios can be met through different supporting devices, and are suitable for the construction logic of the open top method.

[0059] The lap length of the upper longitudinal steel bar 2 and the upper transverse steel bar 5 is 13d, d represents the diameter of the upper transverse steel bar 5, and the lap length is adjusted according to the diameter of the upper transverse steel bar 5; the pouring thickness of the precast layer concrete 6 is 10-15mm, and the thickness of the precast layer concrete 6 is adjusted according to actual needs.

[0060] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A UHPC-based steel truss floor node structure, characterized in that: It includes a steel truss prefabricated floor slab, a shear wall and a supporting device; the steel truss prefabricated floor slab is fixed to the upper part of the supporting device, one end of the steel truss prefabricated floor slab is UHPC concrete, and the other end of the steel truss prefabricated floor slab is a common concrete cast-in-place layer; The steel bar truss prefabricated floor comprises a prefabricated layer of concrete, lower steel bars are arranged on the upper part of the prefabricated layer of concrete, upper steel bars are arranged on the upper part of the lower steel bars, and a plurality of truss diagonal web bars are arranged between the upper steel bars and the lower steel bars.

2. A UHPC-based steel truss floor node structure as claimed in claim 1, characterized in that: The lower steel bars include lower transverse steel bars and lower longitudinal steel bars. A plurality of the lower transverse steel bars and lower longitudinal steel bars are provided, and the plurality of lower transverse steel bars and lower longitudinal steel bars are arranged in a staggered manner.

3. A UHPC-based steel truss floor node structure as claimed in claim 1, characterized in that: The upper steel bars include upper transverse steel bars and upper longitudinal steel bars. A plurality of the upper transverse steel bars and upper longitudinal steel bars are provided, and the plurality of upper transverse steel bars and upper longitudinal steel bars are arranged in a staggered manner.

4. A UHPC-based steel truss floor node structure as claimed in claim 1, characterized in that: A plurality of wall reinforcements are arranged at intervals inside the shear wall, a plurality of reinforcement sleeves are embedded in the shear wall, and the wall reinforcements pass through the reinforcement sleeves and are connected with the upper longitudinal reinforcements of the upper reinforcements and the lower longitudinal reinforcements of the lower reinforcements.

5. A UHPC-based steel truss floor node structure as claimed in claim 1, characterized in that: A template or a steel mesh is arranged on the side of the prefabricated steel truss floor slab, and the template or the steel mesh is installed on the side of the prefabricated steel truss floor slab before concrete pouring.

6. A UHPC-based steel truss floor node structure as claimed in claim 1, characterized in that: The supporting device is a combination of embedded parts and angle steel, or I-beam, or UHPC bracket; The embedded parts are embedded in the shear wall, the upper end surface of the angle steel supports the prefabricated floor slab of the steel bar truss, and the side surface of the angle steel is connected to the embedded parts.

7. A UHPC-based steel truss floor node structure as claimed in claim 6, characterized in that: The upper end surface of the I-beam supports the prefabricated steel truss floor slab; the upper end surface of the UHPC corbel supports the prefabricated steel truss floor slab, the side surface of the UHPC corbel is connected to the shear wall body, and the UHPC corbel is cast by UHPC concrete.

8. A method for using a UHPC-based steel truss floor node structure according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: Tie up the wall reinforcement and the reinforcement and reinforcement sleeves reserved in the wall and connected to the floor slab, and install a support device at one end of the wall reinforcement; Step 2: pouring concrete to the position of the wall reinforcement and curing the poured concrete to a specified strength, thus forming a shear wall; Step 3: Tie the lower longitudinal steel bars, the lower transverse steel bars, and the truss diagonal web bars, and install them on the upper part of the precast concrete layer after the tying is completed. After the installation is completed, hoist the entire structure to one end of the shear wall; Step 4: Install the upper longitudinal steel bars and lower longitudinal steel bars at the slab wall connection nodes, and tie the upper longitudinal steel bars and upper transverse steel bars of the floor slab at the same time; Step 5: Support the side formwork or steel mesh, pour the UHPC concrete in the overlap area, and cure it to the specified strength; Step 6. Remove the side formwork or steel mesh, pour ordinary concrete in the remaining areas, and cure to the specified strength.

9. The method of use according to claim 8, characterized in that: The supporting device is a temporary supporting structure or a permanent supporting structure, the temporary supporting structure is an I-beam or a UHPC corbel, and the permanent supporting structure is a combination of embedded parts and angle steels.

10. The method of use according to claim 8, characterized in that: The lap length of the upper longitudinal steel bars and the upper transverse steel bars is 13d, where d represents the diameter of the upper transverse steel bars; the pouring thickness of the precast layer concrete is 10-15mm.

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