KR101006975B1 - Slim floor system by continuous two-way hollow core slab - Google Patents

Abstract

The present invention is completed by a slim floor structure in which a hollow slab in two directions is formed on the lower flange of the asymmetric H-beam, and at the same time by a continuous two-way hollow slab completed in a structure that stably resists tension through the sequencing of the lower slab reinforcing bar. It relates to a slim floor structure.

According to the present invention, by simply placing the lightweight molding member in two directions without using a deck plate having a deep dance, the weight of the slim floor structure can be easily reduced, and the second two-way hollow slab is completed in a flat plate structure. The long-span structure can be easily constructed by implementing a slim floor structure, and the slim floor structure that secures overall structural stability by sequencing the slab bottom reinforcing bars at the steel cheolbo position by the behavior of the flat plate structure. Can be.

Slim floor, slab rebar, continuous, asymmetric H-beam, 2-way hollow slab

Description

Slim floor structure by continuous two-way hollow core slab

The present invention relates to a slim floor structure for constructing a slab from above the lower flange of the asymmetric H-beam, and more specifically, to reduce the weight and at the same time the slab bottom reinforcement by embedding a lightweight molding member acting as a hollow in two directions The present invention relates to a slim floor structure designed for tensile reinforcement by reinforcement.

Recently, as the demand for high-rise buildings continues to increase, buildings that are constructed of steel structures are on the rise. Steel structured building has superior advantages in space variability, structural stability and durability compared with reinforced concrete structured building. However, as the slab is constructed above the upper part of steel steel beams, the height of the building increases, the weight of the building increases, the cost of construction decreases There are disadvantages.

In order to solve the above disadvantages, a slim floor structure as shown in FIG. 1 has been developed. The slim floor structure is constructed by matching the dance of the slab and the asymmetric H-beams by constructing the slab from the lower flange of the asymmetric H-beams. In other words, the slab is integrated in the state accommodated in the dance of the asymmetric H-beam.

The slim floor structure adopts an asymmetric H-shaped steel beam with a small dance compared to the general floor structure (the structure where the slab is constructed on the upper part of the steel beam), and is completed by increasing the dance of the slab. Since the slab weight is inevitably increased to be completed by using the deck plate, a dance-deep gold deck plate is usually used to reduce the weight of the slab.

Such a slim floor structure can reduce the height of the floor as a whole, reduce the amount of fireproof coating by minimizing the exposed part of the cheolgolbo, and improve the vibration performance and the impact sound reduction effect by increasing the slab's dance (thickness). Has the advantage of. However, the deep gold deck plate has a problem that the force acts in one direction and the efficiency of the structure is lowered, so that the conventional slim floor structure is difficult to apply to the long span structure.

Therefore, the present inventors can develop a new slim floor structure that can be reduced in weight without using a deep gold deck plate and can be advantageously applied to a long span structure by bidirectional dispersion of force.

The present invention was developed to improve the above problems, in the slim floor structure to build a slab from above the lower flange of the asymmetric H-beams slim floor structure that can be reduced in weight without using a deep gold deck plate dancing There is a technical challenge to providing.

In addition, the present invention has another technical problem to provide a slim floor structure that can be advantageously applied to the long span structure by the implementation of a structurally advantageous two-way hollow slab.

In addition, the present invention has another technical problem to provide a slim floor structure to improve the resistance to the tension at the joint end of the asymmetric H-beams and slab through the sequencing of the lower slab reinforcing bar.

The present invention to solve the above technical problem, the upper flange is asymmetric H-shaped beam narrower than the lower flange; Deck plate in the form of a low profile flat plate or dance is installed so that the end is mounted on the lower flange of the asymmetric H-beam; A slab bottom reinforcing bar which is disposed on both sides of the web of the asymmetric H-beams with the webs of the asymmetric H-beams interposed therebetween; A plurality of lightweight molding members disposed spaced apart from each other above the slab lower reinforcement and arranged in a block shape having a short length; A slim floor structure comprising: (1) overlapping joints by penetrating reinforcement, or (2) anchored reinforcing bars on the deck plate; Or (3) direct welding of the slab bottom reinforcement, (4) using stud bolts, (5) using stud bolts and first and second reinforcing bars, or (6) using stud bolts and grid meshes. Or (7) By using a U-shaped gate hardware, a slim floor structure is provided by a continuous two-way hollow slab that realizes continuity of slab lower reinforcing bars.

According to the present invention, the following effects can be expected.

First, it is possible to simply reduce the weight of the slim floor structure by simply placing the lightweight molding member in two directions without using a deep deck plate.

Secondly, since it is completed with a two-way hollow slab, it is implemented as a slim floor structure that behaves as a flat plate structure, so that the long span structure can be easily constructed.

Thirdly, the slab bottom reinforcing bar is stretched at the cheolgolbo position by the behavior of the flat plate structure to complete the slim floor structure to ensure the overall structural stability.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments.

Figure 2 is a schematic diagram showing a slim floor structure by a continuous two-way hollow slab according to the present invention, the present invention is a slim floor structure to build a slab from above the lower flange 120 of the asymmetric H-beams, lightweight molding material It is a technical feature to complete the slim floor structure by realizing the continuation of the slab lower reinforcement 300 while completing the hollow slab in two directions by embedding in two directions.

In other words, the present invention is completed with a slim floor structure in which a hollow slab in two directions is formed on the lower flange 120 of the asymmetric H-shaped steel beam, and is also completed in a structure that stably resists tension through sequencing of the lower slab reinforcing bars. . Since the hollow slab in two directions is a structure in which forces are distributed in both directions, the slim floor structure implemented by the hollow slab in two directions has a behavior of flat plate structure, unlike the conventional slim floor structure, and is structurally advantageous. However, the slim floor structure, which is realized by two-way hollow slab, is a flat plate structure, and unlike the conventional slim floor structure, the static moment is generated at the position of the cheolgolbo, and the upper slab reinforcement can be compressed and the lower slab reinforcement can be tensioned. However, the present invention implements a hollow slab in two directions and at the same time by sequencing the lower slab reinforcing bar to allow the lower slab reinforcement to resist the tension advantageously. Thus, the present invention is completed structurally stable and advantageous slim floor structure by the continuous two-way hollow slab.

Specifically, the slim floor structure by the continuous two-way hollow slab according to the present invention, the upper flange 110 is asymmetric H-shaped beam 100 narrower than the lower flange 120; Deck plate (200) of the low profile plate or dance-shaped bone plate is installed so that the end is mounted to the lower flange 120 of the asymmetric H-beam; A slab lower reinforcing bar 300 which is disposed to face the web 130 of the asymmetric H-shaped steel beams on both sides of the deck plate 200 with the web 130 of the asymmetric H-shaped steel beams interposed therebetween; A plurality of lightly formed molding members disposed spaced apart from each other above the slab lower reinforcement 300 and arranged in parallel in two directions provided with short blocks; The deck plate 200, the upper flange 110 of the asymmetric H-shaped steel beam and the concrete (400) to be poured to a height that is embedded with a lightweight molding material; it is configured to include, and further comprising the sequencing of the lower slab reinforcement (300) Configured to be implemented.

The deck plate 200 is a kind of permanent formwork that is not removed after curing of the concrete 400, any one of flat deck, gold deck, truss deck, etc. can be adopted, but to consider the installation of lightweight molding materials.

Since the lightweight molding member 500 serves as a hollow core that is not filled with the concrete 400, it contributes to the weight reduction of the slab and enables long span construction and makes the slab an excellent stiffness I-shaped cross section slab. Complete The lightweight molding member 500 should select a suitable material in consideration of its role as a hollow core, specifically, styrofoam, hollow plastic, steel, carbon fiber, Metal lath and the like. In addition, the lightweight molding member 500 is a block shape of various shapes having a short length (spherical, box-shaped, spherical shape cut in the convex form, capsule shape deformed in a long shape, the convex part cut in the capsule form, etc.) It is free to choose from and it can also be filled with its interior as well as an empty form.

3 to 11 show various embodiments of the slim floor structure by the continuous two-way hollow slab according to the present invention, which is divided according to the concrete sequencing implementation method of the lower slab reinforcement (300).

3 illustrates an example of implementing the sequencing of the lower slab reinforcement 300 by overlapping joints due to the penetrating reinforcement. That is, while slab bottom reinforcing bars 300 are alternately arranged on both sides of the web 130 of the asymmetric H-beam, while one slab bottom reinforcing bar passes through the web of the asymmetric H-beam, the other slab bottom reinforcing bars It is completed by overlapping with each other. At this time, a perforated hole 135 is formed in advance in the web 130 of the asymmetric H-shaped steel beam to penetrate the slab lower reinforcement (300).

As a result, the slab lower reinforcement 300 is directly connected to the other slab lower reinforcement 300 directly, and as a result, the sequencing of the slab lower reinforcement 300 is realized.

4 illustrates an example of implementing the sequencing of the lower slab reinforcement 300 using the fixing reinforcement 310. That is, the slab lower reinforcement 300 is placed so that the end thereof is positioned on the upper flange 110 of the asymmetric H-shaped steel beam, while the fixing reinforcement 310 is disposed to protrude while overlapping the slab lower reinforcement 300 end portion At the same time as overlapping the reinforcement to the reinforcing bar 300, it is completed by welding to the web 130 of the asymmetric H-shaped steel beam. At this time, the anchoring reinforcement 310 is equally reinforced at the same position on both sides of the web 130 of the asymmetric H-beams.

As a result, the slab lower reinforcement 300 is continuously connected to the anchoring reinforcement 310, the web 130 of the asymmetric H-shaped steel beam, the anchoring reinforcement 310, the slab lower reinforcement 300, as a result Continuation of 300 is realized. In particular, since the two slab lower reinforcement 300 is continuous at the same position with the web 130 of the asymmetric H-shaped steel beams interposed therebetween, the stress center of the slab lower reinforcement 300 is generally coincided. As a result, the structure is more effective in stress flow.

5 is an example of implementing the sequencing through direct welding of the slab lower reinforcement (300). In other words, the slab lower reinforcing bar 300 is completed by bending the end stepped by welding to the lower flange 120 of the asymmetric H-shaped steel beam. At this time, the slab lower reinforcement 300 is subjected to the welding.

As a result, the slab lower reinforcement 300 is continuously connected to the lower flange 120 of the asymmetric H-shaped steel beam, and again the slab lower reinforcement 300, as a result of which the sequencing of the slab lower reinforcement 300 is realized. 5 is also completed in a structure in which the stress center of the slab lower reinforcement 300 coincides with the embodiment of FIG. 4.

6 illustrates an example of implementing the sequencing of the lower slab reinforcement 300 using the stud bolt 320. That is, while the stud bolt 320 is bonded to the lower flange 120 of the asymmetric H-shaped steel beam, the slab lower reinforcement 300 is completed by bending the end of the reinforcement to surround the stud bolt 320.

Thus, as the lower slab reinforcement 300 is constrained to the stud bolt 320, the stud bolt 320 in the lower slab sub-reinforcement 300, the lower flange 120 of the asymmetric H-shaped steel beam, again the stud bolt 320, Continuously continues to the slab lower reinforcement 300, as a result the sequencing of the slab lower reinforcement 300 is realized. 6 is also completed in a structure in which the stress center of the slab lower reinforcement 300 coincides with the embodiment of FIG. 4.

7 and 8 illustrate an example in which the slab bottom reinforcement 300 is continuated using the stud bolt 320 and the first and second reinforcing bars 330 and 340. That is, the stud bolt 320 is joined to the lower flange 120 of the asymmetric H-shaped steel beam and the slab lower reinforcement 300 is reinforced so that its end is positioned on the lower flange 120 of the asymmetric H-shaped steel beam, Prepared by reinforcing the first and second reinforcing bars (330, 340) bent to the first, second reinforcing bars (330, 340) to wrap the stud bolt 320 and at the same time overlapped with the slab lower reinforcement (300) will be. At this time, the first and second reinforcing bars (330, 340) are equally reinforced at the same position on both sides of the web 130 of the asymmetric H-beams.

 FIG. 7 illustrates an example in which the first reinforcing bar 330 surrounds one stud bolt 320 and at the same time overlaps with one slab bottom reinforcing bar 300, and FIG. 8 shows that the second reinforcing bar 340 is two. Wrapping the stud bolt 320 at the same time is an example that the two slab bottom reinforcement to overlap with the reinforcement (300). Here, overlapping joints of the first and second reinforcing bars 330 and 340 and the lower slab reinforcement 300 include contact joints and non-contact joints, and the first and second reinforcing bars 330 and 340 and the lower slab reinforcing bars ( It is possible to transfer stress between the first and second reinforcing bars 330 and 340 and the lower slab reinforcing bar 300 only by closely arranging 300 without directly connecting each other.

As a result, the first and second reinforcing bars 330 and 340 are constrained to the stud bolt 320 and coupled with the lower slab reinforcement 300 and the first and second reinforcing bars 300 and 340 in the first and second reinforcing bars 300. ), The stud bolt 320, the lower flange 120 of the asymmetric H-shaped steel beam, the stud bolt 320, the first and second reinforcing reinforcement (330, 340), the slab lower reinforcement (300) is continuously connected to, As a result, the sequencing of the slab lower reinforcement 300 is realized. 7 and 8 are also completed in a structure in which the stress center of the slab lower reinforcement 300 coincides with the embodiment of FIG. 4.

9 illustrates an example of implementing the sequencing of the lower slab reinforcement 300 using the stud bolt 320 and the grid wire mesh 350. That is, the stud bolt 320 is joined to the lower flange 120 of the asymmetric H-beam, and the slab lower reinforcement 300 is reinforced so that its end is positioned on the lower flange 120 of the asymmetric H-beam, while the grid wire mesh Prepare 350 and pass through the stud bolt 320 through the space between the wires to complete the slab on the lower reinforcement (300). At this time, the grid wire mesh 350 is equally disposed at the same position on both sides of the web 130 of the asymmetric H-beams.

Thus, in the slab lower reinforcement 300, the grating wire mesh 350, the stud bolt 320, the lower flange 120 of the asymmetric H-shaped steel beam, the stud bolt 320, the grating wire mesh 350, the slab lower reinforcement 300 ), And as a result, the sequencing of the slab lower reinforcement 300 is realized. 9 is also finished in a structure in which the stress centers of the slab lower reinforcement 300 coincide with the embodiment of FIG. 4.

10 and 11 illustrate an example of implementing the sequencing of the lower slab reinforcement 300 using the U-shaped gate hardware 360. That is, the U-shaped gate hardware 360 is bonded to the lower flange 120 of the asymmetric H-shaped steel beam, while the slab lower reinforcement 300 is bent to the end of the U-shaped gate hardware 360 to be bent (FIG. 10). Or welding welding (FIG. 11).

Thus, as the lower slab reinforcement 300 is constrained to the U-shaped gate hardware 360, the U-shaped gate hardware 360 in the slab lower reinforcement 300, the lower flange 120 of the asymmetric H-shaped steel beam, and the U-shaped gate again. Continuously continues to the hardware 360, the slab lower reinforcement 300, as a result the sequencing of the slab lower reinforcement (300) is realized. 10 and 11 are completed in a structure in which the stress center of the slab lower reinforcement 300 coincides with the embodiment of FIG. 4.

The present invention has been described in detail above with reference to specific embodiments, but the embodiments are only intended to illustrate the present invention, so that the embodiments substituted, added, and modified within the scope without departing from the spirit of the present invention are also described below. It will be said to belong to the protection scope of the present invention as defined by the claims appended hereto.

1 shows a conventional slim floor structure.

Figure 2 shows a slim floor structure by a continuous two-way hollow slab according to the present invention.

3 to 11 show a specific method for securing the continuity of the two-way hollow slab in the slim floor structure according to the present invention.

<Description of the symbols for the main parts of the drawings>

100: Asymmetric H-beam

200: deck plate

300: slab bottom rebar

310: anchored rebar

320: stud bolt

330: first reinforcing bar

340: second reinforcing bar

350: grid wire mesh

360: U-shaped gate hardware

400: concrete

500: lightweight molding material

Claims (8)

The upper flange 110 is asymmetric H-shaped beam 100 narrower than the lower flange 120; Deck plate (200) of the low profile plate or dance-shaped bone plate is installed so that the end is mounted to the lower flange 120 of the asymmetric H-beam; A slab lower reinforcing bar 300 which is disposed toward the web 130 of the asymmetric H-shaped steel beam at both displaced positions with the web 130 of the asymmetric H-shaped steel beam interposed on the deck plate 200; A plurality of lightly formed molding members disposed spaced apart from each other above the slab lower reinforcement 300 and arranged in parallel in two directions provided with short blocks; Consists of the concrete (400) to be cured to the height of the deck plate 200, the upper flange 110 of the asymmetric H-shaped steel beams and the lightweight molding material is embedded; The slab bottom reinforcement of the both sides is arranged to penetrate the web of the asymmetric H-shaped steel beams overlapping each other, characterized in that the slim floor structure by a continuous two-way hollow slab. The upper flange 110 is asymmetric H-shaped beam 100 narrower than the lower flange 120; Deck plate (200) of the low profile plate or dance-shaped bone plate is installed so that the end is mounted to the lower flange 120 of the asymmetric H-beam; A slab lower reinforcement 300 which is disposed to face the web 130 of the asymmetric H-shaped steel beam at both the same positions with the web 130 of the asymmetric H-shaped steel beam interposed on the deck plate 200; A plurality of lightly formed molding members disposed spaced apart from each other above the slab lower reinforcement 300 and arranged in parallel in two directions provided with short blocks; Consists of the concrete (400) to be cured to the height of the deck plate 200, the upper flange 110 of the asymmetric H-shaped steel beams and the lightweight molding material is embedded; The slab bottom reinforcement is reinforced so that the end is located on the lower flange of the asymmetric H-beam, The web 130 of the asymmetric H-shaped steel beams are interposed at the same position on both sides, and are disposed to protrude while overlapping the lower slab bottom reinforcing bars and overlap the slab lower reinforcement 300, while the web of asymmetric H-shaped steel beams ( A fixing floor 310 is welded to the butt welded to 130); Slim floor structure by a continuous two-way hollow slab characterized in that it further comprises. The upper flange 110 is asymmetric H-shaped beam 100 narrower than the lower flange 120; Deck plate (200) of the low profile plate or dance-shaped bone plate is installed so that the end is mounted to the lower flange 120 of the asymmetric H-beam; A slab lower reinforcement 300 which is disposed to face the web 130 of the asymmetric H-shaped steel beam at the same position on both sides of the deck plate 200 with the web 130 of the asymmetric H-shaped steel beam interposed therebetween; A plurality of lightly formed molding members disposed spaced apart from each other above the slab lower reinforcement 300 and arranged in parallel in two directions provided with short blocks; Consists of the concrete (400) to be cured to the height of the deck plate 200, the upper flange 110 of the asymmetric H-shaped steel beams and the lightweight molding material is embedded; The slab lower reinforcing bar is bent end stepped to a slim floor structure by a continuous two-way hollow slab, characterized in that welded to the lower flange 120 of the asymmetric H-shaped steel beam. The upper flange 110 is asymmetric H-shaped beam 100 narrower than the lower flange 120; A stud bolt 320 joined to the lower flange 120 of the asymmetric H-shaped steel beam at both the same positions with the web 130 of the asymmetric H-shaped steel beam interposed therebetween; Deck plate (200) of the low profile plate or dance-shaped bone plate is installed so that the end is mounted to the lower flange 120 of the asymmetric H-beam; A slab lower reinforcement 300 which is disposed to face the web 130 of the asymmetric H-shaped steel beam at both the same positions with the web 130 of the asymmetric H-shaped steel beam interposed on the deck plate 200; A plurality of lightly formed molding members disposed spaced apart from each other above the slab lower reinforcement 300 and arranged in parallel in two directions provided with short blocks; Consists of the concrete (400) to be cured to the height of the deck plate 200, the upper flange 110 of the asymmetric H-shaped steel beams and the lightweight molding material is embedded; The slab lower reinforcing bar is bent end is bent so as to surround the stud bolt 320, a slim floor structure by a continuous two-way hollow slab. The upper flange 110 is asymmetric H-shaped beam 100 narrower than the lower flange 120; A stud bolt 320 joined to the lower flange 120 of the asymmetric H-shaped steel beam at both the same positions with the web 130 of the asymmetric H-shaped steel beam interposed therebetween; Deck plate (200) of the low profile plate or dance-shaped bone plate is installed so that the end is mounted to the lower flange 120 of the asymmetric H-beam; A slab lower reinforcement 300 which is disposed to face the web 130 of the asymmetric H-shaped steel beam at both the same positions with the web 130 of the asymmetric H-shaped steel beam interposed on the deck plate 200; A plurality of lightly formed molding members disposed spaced apart from each other above the slab lower reinforcement 300 and arranged in parallel in two directions provided with short blocks; Consists of the concrete (400) to be cured to the height of the deck plate 200, the upper flange 110 of the asymmetric H-shaped steel beams and the lightweight molding material is embedded; The slab lower reinforcement is reinforced so that the end is located on the lower flange 120 of the asymmetric H-beam, The first reinforcement is to be reinforced at the same position on both sides of the web 130 of the asymmetric H-shaped beam, bent in a U-shape to wrap the stud bolt 320 and overlap with the lower slab reinforcement 300 Reinforcement 330; Slim floor structure by a continuous two-way hollow slab, characterized in that further comprises. The upper flange 110 is asymmetric H-shaped beam 100 narrower than the lower flange 120; A stud bolt 320 joined to the lower flange 120 of the asymmetric H-shaped steel beam at both the same positions with the web 130 of the asymmetric H-shaped steel beam interposed therebetween; Deck plate (200) of the low profile plate or dance-shaped bone plate is installed so that the end is mounted to the lower flange 120 of the asymmetric H-beam; A slab lower reinforcement 300 which is disposed to face the web 130 of the asymmetric H-shaped steel beam at both the same positions with the web 130 of the asymmetric H-shaped steel beam interposed on the deck plate 200; A plurality of lightly formed molding members disposed spaced apart from each other above the slab lower reinforcement 300 and arranged in parallel in two directions provided with short blocks; Consists of the concrete (400) to be cured to the height of the deck plate 200, the upper flange 110 of the asymmetric H-shaped steel beams and the lightweight molding material is embedded; The slab lower reinforcement is reinforced so that the end is located on the lower flange 120 of the asymmetric H-beam, The web of the asymmetric H-shaped steel beam is interposed at both sides of the same position, bent in a U-shape while simultaneously surrounding the two neighboring stud bolts 320 and simultaneously with the two adjacent slab lower reinforcement (300) Continuous reinforcement of the slab reinforcement, characterized in that it further comprises; The upper flange 110 is asymmetric H-shaped beam 100 narrower than the lower flange 120; A stud bolt 320 joined to the lower flange 120 of the asymmetric H-shaped steel beam at both the same positions with the web 130 of the asymmetric H-shaped steel beam interposed therebetween; Deck plate (200) of the low profile plate or dance-shaped bone plate is installed so that the end is mounted to the lower flange 120 of the asymmetric H-beam; A slab lower reinforcement 300 which is disposed to face the web 130 of the asymmetric H-shaped steel beam at both the same positions with the web 130 of the asymmetric H-shaped steel beam interposed on the deck plate 200; A plurality of lightly formed molding members disposed spaced apart from each other above the slab lower reinforcement 300 and arranged in parallel in two directions provided with short blocks; Consists of the concrete (400) to be cured to the height of the deck plate 200, the upper flange 110 of the asymmetric H-shaped steel beams and the lightweight molding material is embedded; The slab lower reinforcement is reinforcing the end is positioned on the lower flange 120 of the asymmetric H-beam, The web 130 of the asymmetric H-shaped steel beams are placed in the same manner on both sides, the grid wire mesh is placed on the slab lower reinforcement (300) while the stud bolt 320 is passed through the space between the wires ( 350); Slim floor structure by the continuous two-way hollow slab, characterized in that it further comprises. The upper flange 110 is asymmetric H-shaped beam 100 narrower than the lower flange 120; A U-shaped gate hardware 360 bonded to the lower flange 120 of the asymmetric H-shaped steel beam at both the same positions with the web 130 of the asymmetric H-shaped steel beam interposed therebetween; Deck plate (200) of the low profile plate or dance-shaped bone plate is installed so that the end is mounted to the lower flange 120 of the asymmetric H-beam; A slab lower reinforcement 300 which is disposed to face the web 130 of the asymmetric H-shaped steel beam at both the same positions with the web 130 of the asymmetric H-shaped steel beam interposed on the deck plate 200; A plurality of lightly formed molding members disposed spaced apart from each other above the slab lower reinforcement 300 and arranged in parallel in two directions provided with short blocks; Consists of the concrete (400) to be cured to the height of the deck plate 200, the upper flange 110 of the asymmetric H-shaped steel beams and the lightweight molding material is embedded; The slab lower reinforcing bar is an end is inserted into the bent state of the U-shaped gate hardware 360 is bent, or is inserted into the U-shaped gate hardware (360) slim floor by continuous two-way hollow slab, characterized in that the weld rescue.

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