KR20220023017A - Slab Using Steel Fiber Reinforced Concrete - Google Patents

Abstract

Proposed is a slab which comprises: a deck plate; a triangular truss girder placed on an upper end of the deck plate, and including a pair of lower steel wires and a single upper steel wire; a spacer including two body units made of hexahedrons, and an upper plate connecting the two body units, and placed between the deck plate and the triangular truss girder, and fixing the deck plate by a screw fastened with a fastening plate on a lower end of the body units, and fixing the triangular truss girder on an upper end of the head; and a concrete unit placed on an upper end of the deck plate to bury up to an upper end unit of the triangular truss girder. The concrete unit includes folding units formed on both ends on the sides with a center unit in the middle, and is placed in a shape where steel fibers including one or more arch units are distributed at a first ratio or greater. The first ratio is determined to be a ratio which is able to reduce the dry contraction deformation rate of the surface of the slab under the same conditions to be smaller than that of other slabs including an upper distributing bar even if the slab does not include the upper distributing bar formed in a direction vertical to the upper steel wire of the triangular truss girder. The present invention aims to provide a slab which is capable of improving the dry contraction deformation rate performance.

Description

Slab Using Steel Fiber Reinforced Concrete

The present invention relates to a slab using steel fiber reinforced concrete. Specifically, even if the upper reinforcement reinforcement is omitted at the top of the deck plate, the optimal ratio of steel fibers determined by considering the deck plate structure, the role of the upper reinforcement reinforcement and the structure of the steel fibers in detail It is about a slab whose performance is improved by incorporating it into concrete.

In general, a concrete member has excellent compressive strength, durability and rigidity, but has low tensile strength, flexural strength, impact strength and energy absorption capacity. According to these characteristics, the concrete member has a limit in that it is highly likely to be destroyed when a tensile or dynamic load is applied.

In order to solve the above problems, a method of improving physical properties such as tensile force, impact resistance, and peeling resistance by mixing steel fibers for reinforcing concrete in a concrete member is widely used.

In general, steel fibers for reinforcing concrete have a material of steel processed into fibers. When steel fibers having a relatively short length are distributed in a concrete member, physical properties such as tensile strength, flexural strength and shear strength of the large crete can be improved. In addition, it can be a means to increase the resistance to cracking as it has a strong characteristic against impact.

There is a prior study on a method of omitting the upper reinforcing bar by pouring steel fiber concrete on the deck plate by utilizing the characteristics of the steel fiber as described above, which can be referred to Patent Application No. 2014-0054779.

1 is a view for explaining a conventional unreinforced steel fiber concrete-deck plate composite slab.

As can be seen in FIG. 1, the conventional unreinforced steel fiber concrete-deck plate composite slab is cast on the deck plate 10 and the deck plate 10, and the steel fiber 22 is mixed with the concrete 21 and steel fiber concrete. It consists of (20). In the steel fiber concrete 20 , the steel fibers 22 are mixed with the concrete 21 .

In addition, the deck plate 10 is a flat portion 11 of a flat plate; In the first coupling part 12 and the second coupling part 13, and the first coupling part 12 and the second coupling part 13 provided to protrude upward from both sides of the flat part 11, respectively. It includes a first reinforcing coupling portion 14 and a second reinforcing coupling portion 15 provided on the upper portion of the flat portion 11 so as to be spaced apart from each other by a predetermined interval inward. Here, the distance between the first coupling part 12 and the first reinforcing coupling part 14 is the same as the distance between the second coupling part 13 and the second reinforcing coupling part 15, and the first coupling part 12 ) and the first reinforcing coupling portion 14 is configured to be coupled to the upper portion of the second reinforcing coupling portion 15 and the second coupling portion 13 of the previously installed deck plate 10 adjacent to each other.

However, the composite slab having the above-described structure has a problem in that it is difficult to secure sufficient structural support (eg, bending performance). In addition, there is a problem in that it is difficult to reinforce such insufficient bearing capacity only with the structural characteristics of steel fibers, and even if this is reinforced, an excessive ratio of steel fibers is required, which may cause an increase in cost.

Due to the above-described problems, the composite slab as shown in FIG. 1 is not utilized in actual construction sites.

In one aspect of the present invention, in order to solve the above-described problem, a demoulding deck based on a triangular truss girder having stable structural characteristics is used, but the structural characteristics of steel fibers are improved, so that only a minimum ratio of steel fibers is better than a slab including upper reinforcement muscles. An object of the present invention is to provide a slab with improved performance.

In addition, an aspect of the present invention is to provide a more stable support structure by improving the spacer structure of the demolding deck plate.

In addition, in one aspect of the present invention, it is intended to provide different optimal ratios of steel fibers according to the conditions of each slab and the type of steel fibers.

The problems to be solved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. will be able

In one aspect of the present invention for solving the problems as described above, the deck plate; a triangular truss girder positioned on the deck plate and including a pair of lower iron wires and one upper wire, respectively; It includes a body portion formed of two hexahedrons and an upper plate connecting the two body portions, located between the deck plate and the triangular truss girder, and the deck plate by a screw fastened to the fastening plate at the bottom of the body portion a spacer configured to fix the triangular truss girder to the top of the head; and a concrete portion poured so as to be buried in the upper end of the deck plate up to the upper end of the triangular truss girder, wherein the concrete portion includes bent portions at both left and right ends around the central portion, and the steel fiber including one or more arch portions is at least a first ratio is poured in a distributed form, and the first ratio is the same as that of other slabs including the upper reinforcement reinforcement, even if the slab does not include the upper reinforcement reinforcement formed in the direction perpendicular to the upper iron wire of the triangular truss girder. A slab is proposed, which is determined as a ratio capable of reducing the drying shrinkage strain of the slab surface under the conditions.

Here, the two body parts of the spacer, the upper plate, an outer surface plate bent downward from one end of the upper plate to form an outer side surface, the fastening plate, and the inner side surface by bending upward from one end of the fastening plate It may be formed by an inner surface plate to form, the inner surface plate may be configured to support the lower surface of the upper plate.

On the other hand, it is preferable that the first ratio is determined to be lower than the value when the condition of the first slab that is in contact with the ground is lower than the value when the condition of the second slab that is not in contact with the ground is the condition.

In one embodiment of the present invention, the central portion of the steel fiber may be formed in a straight shape, and the bent portions positioned at both ends of the left and right sides may each include one or more arch portions.

In another embodiment of the present invention, the steel fiber includes a central arch portion having a first radius of curvature in the central portion, first and second bent portions respectively formed on the left and right sides of the central arch portion, and the first and It may include first and second extension portions extending to the outer side of the second bent portion.

Preferably, the first ratio is, wherein the steel fiber has a central arch portion having a first radius of curvature in the central portion, first and second bent portions respectively formed on the left and right sides of the central arch portion, and the first and A value in the case of a first type steel fiber including first and second extension portions extending to the outer side of the second bent portion is, the steel fiber has a central portion formed in a straight shape, and the bent portions positioned at both ends of the second bent portion are at least one, respectively. It may be determined to be lower than the value in the case of the second type steel fiber including the arch portion.

In another embodiment of the present invention, the steel fiber, has a convex shape toward the first direction, the first arch portion having a first radius of curvature; a second arch portion having a convex shape in a second direction opposite to the first direction and having a second radius of curvature; a first bent portion connected to the first arch portion and connected to the first arch portion in a direction opposite to a direction in which the first arch portion is connected to the second arch portion; and a second bent portion connected to the second arch portion and connected to the second arch portion in a direction opposite to a direction in which the second arch portion is connected to the first arch portion.

On the other hand, the triangular truss girder includes a plurality, and each of the first and second triangular truss girders adjacent to each other among the plurality of triangular truss girder is the first upper iron wire and the second upper iron wire without reinforcing bar connection work in the field. It can be connected by concrete parts.

According to the embodiments of the present invention as described above, using a triangular truss girder-based demolding deck having stable structural features, and using steel fibers including one or more arch portions, only a small proportion of steel fibers are used to slabs including upper reinforcement muscles. It is possible to provide a slab with improved drying shrinkage strain performance.

In addition, according to the embodiments of the present invention as described above, the structural performance of the slab is improved through the steel fiber, unlike the upper reinforcement muscles, which only play a role in the aspect of drying shrinkage without contributing to the structural performance, which is superior to the bending performance. It is possible to provide a slab having

In addition, according to the embodiments of the present invention as described above, it is possible to bring about cost reduction by providing different optimal ratios of steel fibers according to the conditions of each slab and the type of steel fibers.

In addition, according to the embodiments of the present invention as described above, since there is no need to perform a separate reinforcing reinforcement in the field, it is possible to simplify the construction process.

In addition, as the first and second upper iron wires of each of the adjacent first triangular truss girder and the second triangular truss girder among the plurality of triangular truss girder are connected by the concrete part without rebar connection work in the field, the work process can be simplified. The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned are clearly understood by those of ordinary skill in the art from the following description. it could be

1 is a view for explaining a conventional unreinforced steel fiber concrete-deck plate composite slab.
Figure 2 is a view for explaining the structure of the deck panel utilized in an embodiment of the present invention.
3 and 4 are diagrams for explaining the structure of the improved spacer according to an embodiment of the present invention.
5 and 6 are views for explaining the structure of the upper reinforcement muscles installed to prevent the drying shrinkage deformation in the slab.
7 is a view for explaining a slab structure using concrete reinforced with steel fibers including one or more arches according to an embodiment of the present invention.
8 to 10 are views illustrating types of steel fibers used in embodiments of the present invention.
11 to 13 are diagrams for comparing and explaining pull-out performance according to types of steel fibers.
14 is a view for explaining the advantages of a process according to embodiments of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in several different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part "includes" a certain element, it means that other elements may be further included, rather than excluding other elements, unless otherwise stated.

Figure 2 is a view for explaining the structure of the deck panel utilized in an embodiment of the present invention.

2, the demolding deck provided with the spacer module according to the present invention is a truss girder 100 and a bottom plate 200, and a spacer module provided between the truss girder 100 and the bottom plate 200 ( 300) is included.

The truss girder 100 is, for example, as shown in FIG. 2, a lower chord 120 acting as the main tensile reinforcing bar of the slab, an upper chord 110 acting as a compression reinforcing bar, and the upper chord 110 and It may be configured to include a lattice 130 that functions as a shear strut while integrally fixing the lower chord 120 . On the other hand, when the loading conditions of the load are different, such as when the demolding deck is applied to a continuous slab, it is also possible that the lower chord 120 acts as a compression reinforcing bar and the upper chord 110 acts as a tensile reinforcing bar. The lattice 130 may be fixed to the upper chord 110 and the lower chord 120 by welding. For example, the lattice 130 may be formed of an iron wire or reinforcing bar. The truss girder 100 is arranged to be placed on the spacer module 300 , and specifically, the lower chord 120 of the truss girder 100 is arranged to be supported by the spacer module 300 .

The bottom plate 200 is a part that pours concrete into the deck during slab construction, and is removed after the concrete is cured, and is formed of a metal steel plate. The bottom plate 200 is positioned under the spacer module 300 to support the spacer module 300 and the truss girder 100 disposed thereon. The bottom plate 200 and the spacer module 300 are configured to be coupled by a fixing member (400 in FIG. 3 ) passing through a fastening hole to be described later.

The spacer module 300 according to an embodiment of the present invention is coupled to the bottom plate 200 to support the truss girder 100, and preferably, a sheet of metal plate is folded to form an integral body. there is. The spacer module 300 will be described in more detail below.

3 and 4 are diagrams for explaining the structure of the improved spacer according to an embodiment of the present invention.

Specifically, FIG. 3 is a perspective view of a spacer module according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view of a spacer module according to an embodiment of the present invention.

3 and 4, the spacer module 300 is a metal plate in the longitudinal direction is folded to have an upper plate 310, an outer surface plate 320, a fastening plate 330, and an inner surface plate 340. can be configured.

The upper plate 310 is a part supporting the truss girder 100 , and corresponds to a part on which the lower chord 120 of the truss girder 100 is placed. According to one embodiment, the upper plate 310 may include a reinforcing protrusion 312 protruding in the longitudinal direction in the central portion. The reinforcing protrusion 312 may be formed, for example, by pressing the upper plate 310 upward. In this case, the lower chord 120 of the truss girder 100 may be welded in contact with the reinforcing protrusion 312 of the upper plate 310 . The reinforcing protrusion 312 may serve to increase the bending strength by expanding the cross-sectional secondary moment of the upper plate 310 and to reinforce the supporting force.

The outer surface plate 320 corresponds to an outer side portion of the spacer module 300 . The outer surface plate 320 is bent downward from one end of the upper plate 310 to form an outer side surface. Since the spacer module 300 is made by folding a single sheet of metal, the outer surface plate 320 is integrally formed with the upper plate 310 .

The fastening plate 330 is a bottom portion of the spacer module 300 and corresponds to a portion coupled to the bottom plate 200 in FIG. 2 . The fastening plate 330 may be coupled to the bottom plate 200 by bending one end of the outer surface plate 320 in the horizontal direction.

Since the fastening plate 330 is also formed by folding a single sheet of metal plate, it may be configured to be integrally formed with the upper plate 310 and the outer surface plate 320 .

The fastening plate 330 may include a fastening hole for coupling the fixing member 400 penetrating through the bottom plate 200 . The bottom plate 200 and the spacer module 300 may be screw-coupled through the fastening hole.

According to an embodiment, a cylindrical fastening protrusion 334 protruding upward of the fastening plate 330 and having a thread formed therein may be further formed in the fastening hole. In this case, the fixing member 400 is screwed with the screw thread of the fastening protrusion 334, so that a more stable coupling force can be secured.

According to an embodiment of the present invention, the spacer module 300 is configured to further include an inner side plate 340 extending from the fastening plate 330 . The inner side plate 340 is bent upward from one end of the fastening plate 330 to form an inner side surface, and is configured to support the lower end surface of the upper plate. The inner surface plate 340 may also be formed integrally with the bottom plate 310 , the outer surface plate 320 , and the fastening plate 330 as one sheet of metal plate is folded.

The inner surface plate 340 is folded inward from one end of the fastening plate 330 to form an upward direction in the direction of the upper plate 310 . Accordingly, one end of the inner surface plate 340 may be formed to be in contact with the upper plate 310 . One end of the upper plate 310 and the inner surface plate 340 may be welded or may be configured to simply contact without welding. As one end of the inner surface plate 340 is configured to be in contact with the upper plate 310, it serves to more firmly support the load when the truss girder 100 is placed on the upper plate 310. carry out

According to another embodiment, one end of the inner surface plate 340 does not come into contact with the upper plate 310 and may be spaced apart from each other by a small interval. In this case, when the truss girder 100 is placed on the spacer module 300 , one end of the inner surface plate 340 comes into contact with the upper plate 310 according to the load of the upper plate 310 . It is sufficient if the supporting load can be reinforced.

As such, the inner surface plate 340 is configured to reinforce the supporting force of the upper plate 310 .

In another embodiment of the present invention, the metal spacer head part and the synthetic resin spacer body have a structure formed by injection molding, the truss girder is placed on the head part, and the body part penetrates through the body part to be screwed with the floor part. can In this case, since the head of the metal member and the body of the synthetic resin material are separately manufactured, the manufacturing is slow and the manufacturing cost is high. Problems can arise. In addition, since the bottom plate and the truss girder are connected through the spacer body, which is an insulator, the electrical connection between the bottom plate and the truss girder is cut off. process is needed. Accordingly, since it is necessary to change the electrode connection after the welding process of the spacer for one truss girder is finished, there is a problem in that the workability and economic feasibility of the deck decrease.

In order to solve these problems, in another embodiment of the present invention, the problem of the above-described embodiment can be structurally simply solved by providing a spacer integrally formed by folding using a single sheet of metal plate. That is, the metal spacer module 300 is folded with the upper plate 310 , the outer surface plate 320 , and the fastening plate 330 to replace the synthetic resin body configuration. Accordingly, not only the problem of the bonding force between the dissimilar material of the metal spacer head and the body of the synthetic resin is solved, but also the problem of the bonding strength between the body of the synthetic resin and the bottom of the metal, and the electrical connection problem can be solved at once.

On the other hand, when the spacer module is configured in a U-shape with only the upper plate 310, the outer surface plate 320, and the fastening plate 330, the existing synthetic resin body part serves to reinforce the supporting force of the metal spacer head part. There could be a problem that the bearing capacity reinforcement was lowered. Accordingly, after forming the spacer module in the shape of a U, the inner part of the inner part was further formed of a synthetic resin body to reinforce the supporting power. In consideration of this problem, in a preferred embodiment of the present invention, the spacer module 300 is configured to further include an inner surface plate 340 in addition to the upper plate 310 , the outer surface plate 320 and the fastening plate 330 . .

That is, the configuration of the side portion of the spacer module 300 is composed of the outer surface plate 320 and the inner surface plate 340 , and thus has a structure capable of sufficiently reinforcing the supporting force of the upper plate 310 . Through this, it is possible to completely replace the role of the spacer body part of the synthetic resin material in the existing spacer, and remove all the components of heterogeneous materials such as synthetic resin material from the overall configuration of the spacer module. Therefore, the spacer module according to a preferred embodiment of the present invention solves all of the problems of the spacer body made of synthetic resin, such as bonding force between different materials, increased manufacturing cost, and electrical connection problems, and is easily and inexpensively while maintaining the function and role of the spacer module as it is. It has the advantage of being able to manufacture.

Meanwhile, according to an embodiment of the present invention, the inner surface plate 340 may further include a reinforcing protrusion 342 protruding in the longitudinal direction at the central portion. The reinforcing protrusion 342 may be formed, for example, by pressing the inner surface plate 340 upward. The reinforcing protrusion 342 may serve to increase the bending strength by enlarging the cross-sectional secondary moment of the inner surface plate 340 , and may serve to further reinforce the supporting force of the upper plate 310 .

According to an embodiment, although not shown, the spacer module 300 may further include rust-preventing paint for preventing rust on an externally exposed surface after the bottom plate 200 is removed. That is, when the bottom plate 200 is removed after the demolding deck construction according to an embodiment of the present invention, the lower surface of the fastening plate 330 is exposed on the outer surface of the structure, and thus the exposed metal fastening plate 330 . In order to prevent this corrosion, anti-rust paint may be added to the lower portion of the fastening plate 330 of the spacer module 300 . According to another embodiment, the anti-rust paint may extend not only the fastening plate 330 but also the outer surface plate 320 or the inner surface plate 340 .__

Based on the improved deck structure as described above, the entire slab configuration will be described below.

5 and 6 are views for explaining the structure of the upper reinforcement muscles installed to prevent the drying shrinkage deformation in the slab.

When the slab is formed by pouring concrete directly on the deck panel as described above in relation to FIGS. 2 to 4, the shrinkage proceeds as the moisture in the slab evaporates, and the drying shrinkage strain rate that the slab surface is deformed accordingly is a problem can be

In order to prevent this problem, the upper extensor muscle 410 as shown in FIG. 5 may be used. When the upper chord or upper reinforcing bar 110 of the triangular truss girder 100 shown in FIG. 2 is arranged in the direction along the X-X' axis, the Y-Y' axis forming the vertical direction is As shown in FIG. 5 , the general size may be 3000 mm wide and 600 mm wide and arranged at intervals of 330 mm.

As shown in FIG. 6 , the upper reinforcement muscle 410 may be disposed on top of the deck panel 420 based on the triangular truss girder, and a plurality of deck panels are stud bolts as shown in FIG. 6 . can be connected by

However, in the case of the upper reinforcement muscle 420 described above in relation to FIGS. 5 and 6, it does not provide direct help to the support structure of the deck panel described above in relation to FIGS. 2 to 4, only the dry shrinkage strain of the surface. It is a configuration used to reduce. Accordingly, the thickness and weight of the slab may be unnecessarily increased.

On the other hand, it is preferable to reduce the thickness and weight of the slab and to maintain or further improve the drying shrinkage rate by including the steel fiber including at least one arch part in the concrete to be poured, as will be described later.

7 is a view for explaining a slab structure using concrete reinforced with steel fibers including one or more arches according to an embodiment of the present invention.

As shown in FIG. 7 , it is preferable that the slab according to the present embodiment is configured not to include the upper reinforcement muscle 410 unlike FIG. 6 . Instead, it is proposed that the steel fibers 430 including bent portions at both ends on the left and right around the central portion, and including one or more arch portions, are poured in a distributed form in a first ratio or more.

As the content of the steel fiber 430 is increased, the dry shrinkage strain of the surface, as well as the bending performance and crack suppression effect as described later, are improved, but the cost increase may be a problem. I would like to suggest the optimal steel fiber content according to the structure/condition and the structure/condition of the deck panel.

8 to 10 are views illustrating types of steel fibers used in embodiments of the present invention.

In relation to the structure/condition of the steel fiber applied to the embodiments of the present invention, various types of steel fibers may be considered as shown in FIGS. 8 to 10, but in common at least one or more arch portions (720A/720B in FIG. , 810 in FIG. 9 and 11/12 in FIG. 10) are proposed to be used.

Such at least one arch part is a structure for improving adhesion performance with concrete, and depending on whether or not the arch part is included, even if the upper reinforcement muscle is omitted from the structure described above with respect to FIGS. It was confirmed that the structure has a critical significance in the content ratio of steel fibers to have it.

Specifically, FIG. 8 shows that the central portion 710 is formed in a straight shape, and the bent portions 720 positioned at both ends of the left and right have a structure including one or more arch portions 720A and 720B, respectively, and this is a ‘hook end’ You can call it 'brother'.

Meanwhile, FIG. 9 shows a central arch portion 810 having a first radius of curvature in the central portion 810, first and second bent portions 820 respectively formed on the left and right sides of the central arch portion 810, and It has a structure including the first and second extension portions 830 extending to the outside of the first and second bent portions 820 , and may be referred to as an 'arched shape'.

When the hook-end steel fiber of FIG. 8 and the arched steel fiber of FIG. 9 are compared, the arch portion 810 of the arched steel fiber of FIG. 9 has excellent contact performance with concrete, and accordingly, using the concrete containing the arched steel fiber of FIG. The steel fiber content rate in this case may exhibit similar performance at a lower content rate than the steel fiber content rate in the case of using the concrete including the end hook type steel fibers of FIG. 8 .

However, the difference in the content rate depending on the structure of the steel fiber may be determined in consideration of the effect of improving the bending performance as well as the above-mentioned dry shrinkage strain.

Meanwhile, FIG. 10 shows a double-arc steel fiber structure to further improve performance than the arc-type steel fiber of FIG. 9 .

Specifically, the double-arc steel fiber shown in FIG. 10 includes a first arch portion 11 having a convex shape in a first direction (direction B1) and having a first radius of curvature; a second arcuate portion 12 having a convex shape toward a second direction (B2 direction) opposite to the first direction (B1 direction) and having a second radius of curvature; A first arc connected to the first arch portion 11 and connected to the first arch portion 11 in a direction opposite to the direction in which the first arch portion 11 is connected to the second arch portion 12 . bent part (33); and a second arc connected to the second arch portion 12 and connected to the second arch portion 12 in a direction opposite to the direction in which the second arch portion 12 is connected to the first arch portion 11 . It may include two bent portions 34 .

In addition, as shown in FIG. 10 , a connection part 20 forming a connection part between the first arch part 11 and the second arch part 12 may be included, and the connection part 20 is also curved at both ends. (31, 32) can be formed to further improve adhesion performance with concrete.

As described above, the upper reinforcement muscles only played a role to reduce the surface dry shrinkage deformation without contributing to structural performance, but in the case of the steel fibers illustrated in FIGS. It can be seen that the double-arched steel fiber of FIG. 10 is the most effective structure for improving the bending performance among the various types of steel fibers of FIGS. 8 to 10 .

11 to 13 are diagrams for comparing and explaining pull-out performance according to types of steel fibers.

Specifically, Fig. 11 (a) shows the index for each part for measuring the pull-out load of the end hook-type steel fiber, and Fig. 11 (b) is a graph showing the pull-out load accordingly. As shown in (b) of FIG. 11 , in the case of an end hook-type steel fiber, the pull-out load may be measured as 320N.

In the same manner, Fig. 12 (a) shows the index for each part for measuring the pull-out load of the arcuate steel fiber, and Fig. 12 (b) is a graph showing the pull-out load accordingly. As shown in (b) of FIG. 12 , in the case of an arcuate steel fiber, the pull-out load may be measured to be 350N.

FIG. 13 is a diagram for explaining a pull-out performance improvement mechanism by comparing both graphs.

First, as indicated by the arrow (1), it can be seen that the adhesion resistance length is improved as the arc-type steel fiber is used. In addition, as indicated by the arrow (2), as the arc-type steel fiber is used, the mechanical friction zone is enhanced, and the pull-out performance is enhanced by a combination of these, which can be understood as improving the flexural toughness of concrete. there is.

The comparison described above with reference to FIGS. 11 to 13 also has an aspect to explain why the steel fiber should include at least one arch in the preferred embodiment of the present invention.

On the other hand, as described above, in the embodiments of the present invention, the minimum steel fiber content may be determined differently according to the structure/condition of the deck panel as well as the structure/condition of the steel fiber.

First, in one embodiment of the present invention, the ratio of steel fibers required in the case of a slab in contact with a base (hereinafter referred to as 'first slab') is the same as that of having the slab structure described above with reference to FIG. In the case of a non-adjacent slab (hereinafter referred to as 'second slab'), it is suggested that the ratio of steel fibers is lower than the required ratio.

Here, the required steel fiber ratio is the same in that it means the minimum ratio for further improving the drying shrinkage strain compared to the case where the upper reinforcement muscles are reinforced under the same conditions as described above.

The reason that the ratio of steel fibers required for the first slab is lower than the ratio of steel fibers required for the second slab is that, in general, slabs with a thickness of 300 mm are used for flooring slabs, and because they are in contact with the ground, friction with the ground and moisture evaporation While there is a reduction effect, in the case of the upper slab, a slab with a thickness of 150 mm is used, and it can be understood because it cannot be expected that the above-described floor slab has an effect of reducing friction/water evaporation with the ground.

14 is a view for explaining the advantages of a process according to embodiments of the present invention.

According to the embodiments of the present invention, while reducing the thickness/weight of the slab compared to the case of using the upper reinforcement muscles, it has the effect of having a higher drying shrinkage rate through the minimum steel fiber content as described above. . Moreover, according to the embodiments of the present invention as shown on the right side of Fig. 14, compared to the case of reinforcing the upper reinforcement reinforcement as shown on the left side of Fig. 14, the on-site reinforcing reinforcement process is omitted from the construction may have the effect of simplifying

That is, in the case of using a slab through reinforcing bars such as upper reinforcement reinforcement, while reinforcing reinforcement must be performed directly on the deck panel at the site, according to the embodiments of the present invention, this process can be omitted. have

In addition, in one embodiment of the present invention, the triangular truss girder includes a plurality of first upper iron wire and second upper iron wire of each adjacent first triangular truss girder and second triangular truss girder among the plurality of triangular truss girder. can be connected by the concrete part without rebar connection work in the field. This is because the bending performance is improved by using the steel fiber reinforced concrete according to the embodiments of the present invention, and there is no need to use a separate upper reinforcing bar.

The detailed description of the preferred embodiments of the present invention disclosed as described above is provided to enable any person skilled in the art to make and practice the present invention. Although the above has been described with reference to preferred embodiments of the present invention, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the scope of the present invention. For example, those skilled in the art can use each configuration described in the above-described embodiments in a way in combination with each other.

Accordingly, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The slab according to the embodiments of the present invention as described above may be utilized in various construction fields.

In addition, it can be used in a variety of ways, not only in the general construction field, but also as a bridge top plate, a wind tunnel slab, and the like.

Claims (8)

In the slab,
deck plate;
a triangular truss girder positioned on the deck plate and including a pair of lower iron wires and one upper wire, respectively;
It includes a body portion formed of two hexahedrons and an upper plate connecting the two body portions, located between the deck plate and the triangular truss girder, and the deck plate by a screw fastened to the fastening plate at the bottom of the body portion a spacer configured to fix the triangular truss girder to the top of the head; and
Containing a concrete part poured so as to be buried up to the upper end of the triangular truss girder on the top of the deck plate,
The concrete part,
It includes bent parts at both ends on the left and right around the central part, and the steel fiber including one or more arch parts is poured in a distributed form in a first ratio or more,
The first ratio is the drying shrinkage of the surface of the slab under the same conditions as that of other slabs including the upper reinforcement muscles, even if the slab does not include the upper reinforcement reinforcement formed in the direction perpendicular to the upper iron wire of the triangular truss girder. A slab, determined as a rate at which strain can be reduced. The method of claim 1,
The two body parts of the spacer,
The upper plate, an outer surface plate bent downward from one end of the upper plate to form an outer side surface, the fastening plate, and an inner surface plate bent upward from one end of the fastening plate to form an inner side surface,
The inner surface plate is configured to support the lower surface of the upper plate, the slab. The method of claim 1,
The first ratio is determined to be lower than the value when the condition of the first slab in contact with the ground is lower than the value when the condition of the second slab is not in contact with the ground. The method of claim 1,
The steel fiber has a central portion formed in a straight shape, and the bent portions positioned at both ends of the left and right sides each include one or more arch portions. The method of claim 1,
The steel fiber is
a central arch portion having a first radius of curvature in the central portion;
first and second bent portions respectively formed on the left and right sides of the central arch portion, and
The slab comprising first and second extensions extending outwardly of the first and second bent portions. The method of claim 1,
The first ratio is
The steel fiber,
a central arch portion having a first radius of curvature in the central portion;
first and second bent portions respectively formed on the left and right sides of the central arch portion, and
A value in the case of a first type steel fiber including first and second extension portions extending to the outer side of the first and second bent portions is,
The steel fiber,
The slab, wherein the central portion is formed in a straight shape, and the bent portions located at both ends of the left and right are determined to be lower than the value in the case of the second type steel fiber including one or more arch portions, respectively. The method of claim 1,
The steel fiber is
a first arch portion having a convex shape in a first direction and having a first radius of curvature;
a second arch portion having a convex shape in a second direction opposite to the first direction and having a second radius of curvature;
a first bent portion connected to the first arch portion and connected to the first arch portion in a direction opposite to a direction in which the first arch portion is connected to the second arch portion; and
and a second bent portion connected to the second arch portion and connected to the second arch portion in a direction opposite to a direction in which the second arch portion is connected to the first arch portion. The method of claim 1,
The triangular truss girder includes a plurality,
Of the plurality of triangular truss girder, the first and second upper iron wires of each adjacent first triangular truss girder and second triangular truss girder are connected by the concrete part without rebar connection work in the field.

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