A self-supporting composite floor slab and its construction method

Abstract

The present invention relates to a self-supporting composite floor slab, which comprises a locally ribbed precast bottom slab and a post-cast concrete layer cast on the upper side of the locally ribbed precast bottom slab; the locally ribbed precast bottom slab comprises a precast concrete slab and a number of stiffness strengthening units arranged at intervals on the upper side of the precast concrete slab. The purpose of the present invention is to provide a self-supporting composite floor slab and its construction method that can overcome the above problems, and can significantly improve the construction speed and reduce the cost. The advantages of the present invention are as follows: 1. By setting the stiffness strengthening units, the stiffness of the locally ribbed precast bottom slab can be increased, realizing the self-supporting and formwork-free construction on site, significantly accelerating the construction speed and reducing the on-site construction cost; 2. The stiffness strengthening units are only arranged in the mid-span area of the locally ribbed precast bottom slab, which can reduce the material consumption; 3. The two ends of the planar steel bar truss extend out of the concrete ribs, which can relieve the stress concentration caused by the cross-section change and avoid the cracking of the floor slab.

Description

Technical Field

[0001] The present invention relates to the technical field of prefabricated buildings, and particularly to a self - supporting composite floor slab and a construction method thereof. Background Art

[0002] When the existing precast concrete buildings adopt composite floor slabs, supports are usually provided below during the construction stage. When the storey height is large, the support system is complex and costly. Therefore, in order to speed up the construction speed, reduce the project measure costs, it has great practical value to achieve the self - supporting and formwork - free of precast structures. Summary of the Invention

[0003] The purpose of the present invention is to provide a self - supporting composite floor slab and a construction method thereof that can overcome the above problems, which can significantly improve the construction speed and reduce the cost.

[0004] The purpose of the present invention is achieved by the following technical solutions:

[0005] A self - supporting composite floor slab includes a locally ribbed precast bottom slab and a post - cast concrete layer poured on the upper side of the locally ribbed precast bottom slab; the locally ribbed precast bottom slab includes a precast concrete slab and a number of stiffness - strengthening units arranged at intervals on the upper side of the precast concrete slab. The long axes of the stiffness - strengthening units are parallel to the span direction of the precast concrete slab. The stiffness - strengthening unit includes a stiffness - strengthening truss and a concrete rib poured on the upper part of the stiffness - strengthening truss. Both ends of the stiffness - strengthening truss extend beyond the concrete rib, and the lower part of the stiffness - strengthening truss is buried in the precast concrete slab; the stiffness - strengthening units are arranged in pairs and symmetrically distributed about the central axis of the precast concrete slab; the distance between the end of the stiffness - strengthening unit and the end of the corresponding side precast concrete slab is greater than 0.15 times the span of the self - supporting composite floor slab and less than 0.4 times the span of the self - supporting composite floor slab.

[0006] A construction method of a self - supporting composite floor slab includes the following steps:

[0007] S1. Weld a flat steel bar truss, U - shaped connecting steel bars and reinforcing steel bars to form a stiffness - strengthening truss. Invert the stiffness - strengthening truss and place it in a mold to pour concrete, and a concrete rib is formed on the upper part of the stiffness - strengthening truss, and finally a stiffness - strengthening unit is made;

[0008] S2. Place a steel mesh sheet and a three - dimensional steel bar truss into the mold of the precast concrete slab and pour concrete;

[0009] S3. Before the concrete of the precast concrete slab begins to set, press the stiffness - strengthening truss under the concrete rib into the concrete, and wait for the concrete to harden to make a locally ribbed precast bottom slab;

[0010] S4. Hook the lifting hook to the upper chord nodes of the planar steel bar truss extending out from both ends of the stiffness strengthening unit, hoist the locally ribbed precast floor slab into place, and pour post-cast concrete on its surface to form a post-cast concrete layer, thus completing the construction of the non-supporting composite floor slab.

[0011] Compared with the prior art, the advantages of the present invention are as follows:

[0012] 1. By setting the stiffness strengthening unit, the stiffness of the locally ribbed precast floor slab can be increased, realizing no support and no formwork during on-site construction, significantly accelerating the construction speed and reducing the on-site construction cost;

[0013] 2. The stiffness strengthening unit is only set in the mid-span area of the locally ribbed precast floor slab, which can reduce material consumption;

[0014] 3. The two ends of the planar steel bar truss extend out of the concrete ribs, which can relieve the stress concentration caused by the cross-section change and avoid floor slab cracking;

[0015] 4. The extended section of the planar steel bar truss can also serve as the lifting point of the precast component, avoiding the setting of special lifting rings and reducing material consumption;

[0016] 5. The area near both ends of the slab span where the stiffness strengthening unit is not set can be used for embedding pre-buried pipelines, so that the pre-buried pipelines do not need to pass through the stiffness strengthening unit, improving the construction efficiency;

[0017] 6. Pressing the stiffness strengthening unit into the precast concrete slab before initial setting can avoid contaminating the stiffness strengthening unit during concrete pouring and ensure that the bottom surface of the concrete rib of the stiffness strengthening unit is closely attached to the top surface of the precast concrete slab. Description of the Drawings

[0018] Figure 1 is a three-dimensional structural schematic diagram of an embodiment of a non-supporting composite floor slab of the present invention.

[0019] Figure 2 is a three-dimensional structural schematic diagram of the locally ribbed precast floor slab.

[0020] Figure 3 is a three-dimensional structural schematic diagram of the stiffness strengthening unit.

[0021] Figure 4 is a construction method of a non-supporting composite floor slab (step 1).

[0022] Figure 5 is a construction method of a non-supporting composite floor slab (step 2).

[0023] Figure 6 is a construction method of a non-supporting composite floor slab (step 3).

[0024] Figure 7 It is a construction method (step 4) of a self - supporting composite floor slab.

[0025] Figure 8 It is a schematic diagram of embedded pipelines in a self - supporting composite floor slab.

[0026] Label description: 1. Locally ribbed precast bottom slab; 1 - 1. Precast concrete slab; 1 - 2. Steel mesh; 1 - 3. Three - dimensional steel truss; 2. Cast - in - place concrete layer; 3. Stiffness strengthening unit; 3 - 1. Concrete rib; 3 - 2. Planar steel truss; 3 - 3. U - shaped connecting steel bar; 3 - 4. Reinforcing steel bar; 4. Embedded part; 5. Embedded pipeline. Specific implementation mode

[0027] The content of the present invention will be described in detail below in conjunction with the accompanying drawings of the specification and embodiments:

[0028] As Figure 1-3 shown is a schematic diagram of an embodiment of a self - supporting composite floor slab provided by the present invention.

[0029] A self - supporting composite floor slab, which comprises a locally ribbed precast bottom slab 1 and a cast - in - place concrete layer 2 poured on the upper side of the locally ribbed precast bottom slab 1;

[0030] The locally ribbed precast bottom slab 1 includes a precast concrete slab 1 - 1 and a plurality of stiffness strengthening units 3 arranged at intervals on the upper side of the precast concrete slab 1 - 1. The long axes of the stiffness strengthening units 3 are parallel to the span direction of the precast concrete slab 1 - 1. The stiffness strengthening unit 3 includes a stiffness strengthening truss and a concrete rib 3 - 1 poured on the upper part of the stiffness strengthening truss. Both ends of the stiffness strengthening truss extend beyond the concrete rib 3 - 1, and the lower part of the stiffness strengthening truss is buried in the precast concrete slab 1 - 1;

[0031] The stiffness strengthening units 3 are arranged in pairs and symmetrically distributed about the central axis of the precast concrete slab 1 - 1;

[0032] The distance between the end of the stiffness strengthening unit 3 and the end of the corresponding side precast concrete slab 1 - 1 is greater than 0.15 times the span of the self - supporting composite floor slab and less than 0.4 times the span of the self - supporting composite floor slab.

[0033] The locally ribbed precast bottom slab 1 further includes a steel mesh 1 - 2 buried in the precast concrete slab 1 - 1. A three - dimensional steel truss 1 - 3 is fixed on the upper side of the steel mesh 1 - 2, and the upper part of the three - dimensional steel truss 1 - 3 extends out of the precast concrete slab 1 - 1;

[0034] The three - dimensional steel truss 1 - 3 is parallel to the stiffness strengthening unit 3 and is located between two stiffness strengthening units 3.

[0035] The three-dimensional steel bar truss 1-3 includes an upper chord bar and two lower chord bars, and the upper chord bar and the lower chord bars are connected by diagonal web bars to form a whole.

[0036] When the precast concrete slab 1-1 is cast, the lower chord bars of the three-dimensional steel bar truss 1-3 and the lower sections of the diagonal web bars are located within the precast concrete slab 1-1.

[0037] The stiffness strengthening truss includes two vertically arranged planar steel bar trusses 3-2; each planar steel bar truss 3-2 includes an upper chord bar, a lower chord bar, and diagonal web bars connecting the upper chord bar and the lower chord bar, and a U-shaped connecting steel bar 3-3 is provided between the lower chord bars of the two planar steel bar trusses 3-2;

[0038] The U-shaped connecting steel bar 3-3 is welded to the ends and the middle of the two planar steel bar trusses 3-2.

[0039] The lower chord bars and the lower sections of the diagonal web bars of the planar steel bar truss 3-2 extend outside the concrete rib 3-1, and both ends of the planar steel bar truss 3-2 extend outside the concrete rib 3-1. The planar steel bar truss 3-2 and the concrete rib 3-1 are in an interlocking state.

[0040] Reinforcing steel bars 3-4 are respectively provided at both ends of the stiffness strengthening truss, and the reinforcing steel bars 3-4 are connected between the lower chord bars of the planar steel bar trusses 3-2.

[0041] The precast concrete slab 1-1 is made of concrete, is integrally sheet-shaped, and its top surface is a rough surface; the steel bars in the span direction of the steel bar mesh 1-2 extend out of the precast concrete slab 1-1.

[0042] As Figure 4-8 shown is a schematic diagram of a construction method of a self-supporting composite floor slab provided by the present invention.

[0043] A construction method of a self-supporting composite floor slab includes the following steps:

[0044] S1. Weld the planar steel bar truss 3-2, the U-shaped connecting steel bar 3-3, and the reinforcing steel bar 3-4 to form a stiffness strengthening truss, invert the stiffness strengthening truss and place it in a mold to cast concrete, and a concrete rib 3-1 is formed on the upper part of the stiffness strengthening truss, and finally a stiffness strengthening unit 3 is made (see Figure 4 );

[0045] S2. Place the steel bar mesh 1-2 and the three-dimensional steel bar truss 1-3 into the mold of the precast concrete slab 1-1 and cast concrete (see Figure 5 );

[0046] S3. Before the concrete of the precast concrete slab 1-1 begins to set, press the stiffness strengthening truss on the lower side of the concrete rib 3-1 into the concrete, and a locally ribbed precast bottom slab 1 is made after the concrete hardens (seeFigure 6 )

[0047] S4. Hook the lifting hook to the upper chord nodes of the planar steel bar truss 3-2 extending outwards at both ends of the stiffness strengthening unit 3, hoist and place the locally ribbed precast floor slab 1 in place, and pour post-cast concrete on its surface to form a post-cast concrete layer 2, thus completing the construction of the non-supporting composite floor slab (see Figure 7 ).

[0048] In step S3, the bottom surface of the concrete rib 3-1 is closely attached to the top surface of the precast concrete slab 1-1.

[0049] In step S3, the stiffness strengthening units 3 are arranged in pairs and symmetrically distributed with respect to the central axis of the precast concrete slab 1-1. Before pouring the post-cast concrete layer 2, place the embedded parts 4 and the embedded pipelines 5 between the two stiffness strengthening units 3 (see Figure 8 ).

[0050] The present invention is not limited to the above embodiments. Any technical solutions identical or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A self - supporting composite floor slab, characterized in that: It includes a locally ribbed precast bottom slab (1) and a post-cast concrete layer (2) cast on the upper side of the locally ribbed precast bottom slab (1); The locally ribbed precast bottom slab (1) includes a precast concrete slab (1-1) and a number of stiffness strengthening units (3) arranged at intervals on the upper side of the precast concrete slab (1-1). The major axis of each stiffness strengthening unit (3) is parallel to the span direction of the precast concrete slab (1-1). The stiffness strengthening unit (3) includes a stiffness strengthening truss and a concrete rib (3-1) cast on the upper part of the stiffness strengthening truss. Both ends of the stiffness strengthening truss extend beyond the concrete rib (3-1), and the lower part of the stiffness strengthening truss is embedded in the precast concrete slab (1-1); The stiffness strengthening units (3) are arranged in pairs and symmetrically distributed about the central axis of the precast concrete slab (1-1); The distance between the end of the stiffness strengthening unit (3) and the end of the corresponding side precast concrete slab (1-1) is greater than 0.15 times the span of the self-supporting composite floor slab and less than 0.4 times the span of the self-supporting composite floor slab; The stiffness strengthening truss includes two vertically arranged planar steel bar trusses (3-2); Each planar steel bar truss (3-2) includes an upper chord, a lower chord, and diagonal web members connecting between the upper chord and the lower chord. A U-shaped connecting steel bar (3-3) is provided between the lower chords of the two planar steel bar trusses (3-2); The lower chord and the lower section of the diagonal web member of the planar steel bar truss (3-2) extend beyond the concrete rib (3-1), and both ends of the planar steel bar truss (3-2) extend beyond the concrete rib (3-1); The bottom surface of the concrete rib (3-1) is closely attached to the top surface of the precast concrete slab (1-1).

2. The self - supporting composite floor slab according to claim 1, characterized in that: The locally ribbed precast bottom slab (1) further includes a steel bar mesh (1-2) embedded in the precast concrete slab (1-1). A three-dimensional steel bar truss (1-3) is fixed on the upper side of the steel bar mesh (1-2), and the upper part of the three-dimensional steel bar truss (1-3) extends out of the precast concrete slab (1-1); The three-dimensional steel bar truss (1-3) is parallel to the stiffness strengthening unit (3) and is located between the two stiffness strengthening units (3).

3. The self - supporting composite floor slab according to claim 1, characterized in that: Reinforcing steel bars (3-4) are respectively provided at both ends of the stiffness strengthening truss, and the reinforcing steel bars (3-4) are connected between the lower chords of the planar steel bar trusses (3-2).

4. The self - supporting composite floor slab according to claim 2, characterized in that: The precast concrete slab (1-1) is made of concrete, is integrally sheet-shaped, and its top surface is a rough surface; the steel bars in the span direction of the steel bar mesh (1-2) extend out of the precast concrete slab (1-1).

5. A construction method of a self - supporting composite floor slab, characterized in that, It includes the following steps: S1. Weld the planar steel bar truss (3-2), the U-shaped connecting steel bar (3-3), and the reinforcing steel bar (3-4) to form a stiffness strengthening truss. Invert the stiffness strengthening truss and place it in a mold to pour concrete, and form a concrete rib (3-1) on the upper part of the stiffness strengthening truss, and finally make the stiffness strengthening unit (3); S2. Place the steel bar mesh (1-2) and the three-dimensional steel bar truss (1-3) into the mold of the precast concrete slab (1-1) and pour concrete; S3. Before the concrete of the precast concrete slab (1-1) starts to set, press the stiffness strengthening truss under the concrete rib (3-1) into the concrete, and after the concrete hardens, a locally ribbed precast bottom slab (1) is made. S4. Hook the lifting hook on the upper chord nodes of the planar steel truss (3-2) extending out from both ends of the stiffness strengthening unit (3), hoist and place the locally ribbed precast bottom slab (1) in place, and pour post-cast concrete on its surface to form a post-cast concrete layer (2), thus completing the construction of the support-free composite floor slab.

6. The construction method of a self - supporting composite floor slab according to claim 5, characterized in that: In step S3, the bottom surface of the concrete rib (3-1) is closely attached to the top surface of the precast concrete slab (1-1).

7. The construction method of a self - supporting composite floor slab according to claim 5, characterized in that: In step S3, the stiffness strengthening units (3) are arranged in pairs and symmetrically distributed about the central axis of the precast concrete slab (1-1). Before pouring the post-cast concrete layer (2), embedment parts (4) and embedded pipelines (5) are placed between the two stiffness strengthening units (3).

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