KR20100133668A - Partially embedded composite slab - Google Patents

Abstract

PURPOSE: A partially embedded composite slab is provided to prevent a fracture caused by the progressing of cracking and to evenly distribute a load without installation of a distribution bar. CONSTITUTION: A partially embedded composite slab comprises a tension resistant member(20), a lower steel plate(10), an upper plate, concrete, and shear connection members(30,31). The tension resistant member has a joint hole on the top. The lower steel plate has a groove(10a) on the bottom. The upper plate is installed on the top of the lower steel plate. The concrete is placed between the lower steel plate and the upper plate. The shear connection members are attached to the bottom of the upper plate and buried in the concrete.

Description

Partial recessed composite floor plate {PARTIALLY EMBEDDED COMPOSITE SLAB}

The present invention relates to a composite bottom plate made of concrete and steel, and more particularly, having an upper steel plate, concrete, a corrugated lower steel plate, a tensile resistance member, and a shear connection member to increase resistance to shear failure. The present invention relates to a partially embedded composite bottom plate which can increase the flexural strength of the bottom plate and achieve the effect of reducing the weight of the member.

In general, bridge decks are constructed of reinforced concrete slabs, but such conventional reinforced concrete slabs have a high self-weight and low rigidity, which lowers the load capacity and durability of the deck. Repair and reinforcement work required a lot of manpower and cost. In addition, there is a problem in that the construction cost is increased because the installation by supporting members and formwork, such as copper bar and cast concrete.

In addition, recently, the reduction of the weight of the bottom plate is a big issue due to the long span of the bridge structure.

In order to solve the problem of the reinforced concrete deck, a composite deck consisting of a steel plate and concrete has been proposed. Synthetic bottom plate is to cast concrete to have a predetermined thickness on the lower plate made of steel plate and to produce the lower plate and concrete in a combined state, the tensile stress caused by the common load and self-weight to bear the lower plate, Compressive stress is a structure that makes the concrete bear.

Such a synthetic deck has been attracting much attention because it can reduce its own weight without a reduction in strength and rigidity compared to conventional reinforced concrete deck. Composite decking mainly uses tensile resistance members as formwork, which can be economically benefited from the simplification of the process and the shortening of the construction period.

However, the above-described conventional composite deck has a problem that it is difficult to avoid the punching shear failure, which is a type of failure that must be avoided in the structure, because the crack propagation and the crack width caused by the concentrated load of a vehicle using a bridge cannot be suppressed. There was this.

1 is a view showing a conventional composite bottom plate. The conventional composite bottom plate shown in FIG. 1 is provided with an I-shaped steel 103 having a hole formed on the lower plate 102 supported by the mold 101 to have a predetermined interval in the transverse direction, and to penetrate the hole. After installing the lower reinforcement 104 and the upper reinforcement reinforcement 105 on the bottom plate, the concrete 106 is completed by placing and curing.

However, the conventional composite bottom plate requires the installation of the lower back muscle for even distribution of the load, and for the installation of the lower back muscle, it is necessary to drill and weld on the section steel. Has become a problem that the complexity and construction period and construction costs increase.

In addition, the above-described conventional composite floor plate has a problem that the work cost and the construction cost increases because the compression reinforcement and the reinforcement reinforcing bar should be installed on the upper part of the lower plate.

Moreover, in the conventional composite floorboard, the position where the hollow abdomen of the inverse T-shaped steel and concrete are synthesize | combined is generally a neutral axis. However, an increase in the strain of the lower steel due to the increase in load causes an increase in the neutral axis, and there is a great possibility of shear failure due to the generation of additional tensile stress. In particular, research on high-strength steels has been actively conducted in recent years, and the use of such high-strength steels causes more strains, so that the brittleness at the position where the hollow abbreviation of the inverted T-shaped steel and the concrete are synthesized in the conventional composite slab. There was a problem that could bring about destruction.

The present invention is to solve the above-mentioned problems of the prior art, the object of the present invention is to increase the shear resistance of the bottom plate to suppress the punching shear failure, to suppress the growth of cracks and the increase in crack width brittleness due to large deflection It is an object of the present invention to provide a partially embedded composite bottom plate which can prevent breakage.

In addition, another object of the present invention is to provide a partially embedded composite floor plate that can distribute the load evenly without installing a distribution bar, and does not require compressed steel.

Another object of the present invention is that the neutral axis is increased due to the increase in the strain of the lower steel plate with the increase of the load, and in particular, even if a high-strength steel is used, there is a risk of brittle fracture at the joint portion of the hollow cover of the inverted T-beam and the concrete. It is to provide a partially embedded composite bottom plate that can be prevented.

In order to solve the above object, the partially embedded composite bottom plate according to the present invention is supported by a mold, the tensile resistance member having a fastening hole formed in the upper end, and the upper end of the tensile resistance member is inserted and fixed and concave to the lower side A lower steel plate having a corrugated shape having a groove formed therein, an upper plate installed on an upper side of the lower steel plate, concrete placed between the lower steel plate and the upper plate, and attached to a bottom surface of the upper plate and attached to the concrete. It is characterized by having a shear connection material embedded.

Here, the tensile resistance member is characterized in that the steel made of inverse T shape.

In addition, the upper plate is characterized in that made of a material for distributing the load of the vehicle acting on the top in two directions.

In addition, the shear connector is formed in a J-shape, characterized in that consisting of a first shear connector made of a hook which is fastened to the fastening hole of the tensile resistance member, and a second shear connector made of a stud installed head.

The first shear connector and the second shear connector is characterized in that at least one arranged within the shear stress section by the load of the vehicle acting on the upper portion of the upper plate.

In addition, the fastening of the first shear connector and the tensile resistance member is characterized in that made in the concave groove of the lower steel plate.

In addition, the epoxy adhesion material containing the bauxite is further formed between the upper end of the tensile resistance member and the concrete.

In addition, the concrete is characterized in that the self-filling concrete.

According to the composite bottom plate of the present invention having the above-described configuration, the structure of the tensile resistance member of the inverse T-shaped steel and the lower steel plate of the corrugated shape can remove the concrete of the tension portion, thereby making it possible to reduce the weight of the bottom plate own weight. Accordingly, it is possible to provide a composite bottom plate suitable for long and long spans, which has an effect of reducing the cross-section of the upper and lower structures of the bridge and reducing the amount of members. In addition, due to the configuration of the high strength corrugated lower steel sheet, it is possible to suppress the occurrence of shear fracture between the hollow abdomen and the concrete due to the increase in load, and to increase the shear resistance from welding with the lower reverse T-shaped steel when the punching shear failure occurs.

In addition, by installing an upper plate capable of distributing load in two directions, the load distribution effect can be maximized to increase the resistance to punching shear failure, and the upper plate can be installed on top of concrete to increase the bending strength of the bottom plate. It is possible to distribute the load evenly without installing the lower power bar and there is an advantage that does not require the compression rebar.

In addition, the shear connector used for the synthesis of the upper plate, concrete, and tensile resistance member plays a role of shear stirrup, and prevents brittle fracture due to large deflection of the structure by suppressing crack propagation and increase in crack width. In addition, epoxy adhesives using bauxite also have the advantage of suppressing the shear failure between the hollow abdomen and concrete due to the increase of frictional force.

Hereinafter, with reference to the accompanying drawings will be described in detail the partially embedded composite bottom plate according to the present invention.

2 and 3 are views illustrating a partially embedded composite bottom plate according to the present invention, and FIGS . 4 and 6 are cross- sectional views of the partially embedded composite bottom plate according to the present invention.

2 to 6, the partially embedded composite bottom plate 1 according to the present invention includes a lower steel plate 10, a tensile resistance member 20, a concrete layer 40, and an upper plate ( 60) and shear connecting members (30, 31).

The tensile resistance member 20 is supported by the mold (2). In the present embodiment, the mold 2 is an I-shaped steel, but is not necessarily limited to this, it is also possible to use a steel box or the like.

The tensile resistance member 20 may be made of an I-shaped steel, but in the present embodiment, the tensile resistance member 20 is made of an inverted T-shaped steel arranged upside down.

A plurality of fastening holes 21 are formed in the upper end portion of the tensile resistance member 20, that is, the abdomen of the inverse T-shaped steel, along the longitudinal direction of the tensile resistance member 20. The upper end of the fastening hole 21 of the tensile resistance member 20 is embedded in the lower steel plate 20 and the concrete layer 40 to be described later for the composite behavior of the concrete layer and the tensile resistance member.

On the other hand, the lower steel plate 10 is installed on the upper portion of the tensile resistance member 20 and the lower portion of the concrete layer 40. The lower steel plate 10 has a concave groove 10a bent toward the lower side, that is, the mold 2 side, and is configured to form a wave shape as a whole. The lower steel plate 10 is composed of a plurality of units cut from the concave groove 10a having a corrugated steel plate having the concave groove 10a formed therein, and the tensile resistance member ( 20 is inserted into the upper end portion and fixed to the tensile resistance member 20 by means of welding or the like, so that the tensile resistance member 20 and the lower steel plate 10 are fixed at the concave groove side.

As described above, the lower steel plate 10 is also used as a permanent formwork with the role of the structural member, even when precast production and site casting, the installation of the formwork and demoulding is unnecessary, simplifying the work. Therefore, it is possible to reduce the work and construction period and reduce the construction cost due to the installation of the copper bar and formwork between the girder required in the conventional reinforced concrete deck plate.

In addition, due to the configuration of the lower steel plate 10 of the corrugated groove formed with concave grooves, the area between the steel and the concrete joint is increased, the shear caused by the increase in the neutral shaft due to the increase in the strain of the inverse T-shaped steel flange portion when the load increases later Brittle destruction of wealth can be prevented.

In other words, as the load continues to increase by the vehicle in the upper portion of the bridge, the strain of the lower reverse T-beam also increases, indicating an increase in the neutral axis. In particular, high-strength steels have a higher strength than conventional general strength steels, but have a constant elastic modulus, resulting in a larger deflection. Increase the likelihood of brittle fracture at the joint between the abdomen and the concrete. In the present invention, as shown in Figures 5 and 6, by the configuration of the lower steel plate 10 of the corrugated shape, the hollow layer of the concrete layer 40 and the tensile resistance member 20 of the inverse T-shaped steel and By increasing the contact area of, the concrete in the hollow part not only resists the shear force but also the frictional force between the hollow abdomen and the concrete surface, which prevents brittle fracture by using the attachment material described below. In addition, it is possible to reduce the weight of the bottom plate weight by removing the concrete of the tension portion, thereby providing an effective effect of reducing the cross-sectional structure and the amount of members of the upper and lower structures of the bridge and can provide a synthetic floor plate suitable for long distance.

In addition, as shown by the dotted lines of Figs. 4 and 5, the structure of the lower steel plate of the corrugated shape includes the abdominal portion of the inverse T-shaped steel, which is a tensile resistance member, in the shear stress area due to the wheel load, It can act as a binding force.

The upper plate 60 is disposed on the upper side of the lower steel plate 10.

The upper plate 60 is preferably made of a material for distributing the load of the vehicle acting on the upper portion of the upper plate in two directions. In the present embodiment, the upper plate 60 is made of a steel plate. The asphalt pavement layer (not shown) is installed on the upper portion of the upper steel plate 60 as in the conventional bridge deck.

By the upper plate 60, it is possible to maximize the load distribution effect by evenly distributing the concentrated load of the vehicle to the entire bottom plate, thereby preventing the punching shear failure represented by the conventional reinforced concrete bottom plate and the partially embedded composite bottom plate It can be suppressed.

In addition, since the upper plate can function as compressive reinforcement and reinforcement reinforcement, not only compression and reinforcement reinforcement are necessary, but also need to be manufactured in advance in the factory and installed in the field, reinforcement work of compression reinforcement and reinforcement reinforcement Since it can be omitted, the labor cost can be reduced by reducing the labor.

Recently, interest in securing stability in the event of a large earthquake has increased considerably in Korea, and as part of it, there is an advantage in that it is possible to secure stability against earthquakes with minimum reinforcement from lightening of the superstructure during an earthquake.

Concrete is poured between the lower steel plate 10 and the upper plate 60 to form a concrete layer 40. In order to fill the space between the lower steel plate and the upper plate in consideration of the workability of the concrete placing work by the installation of the upper plate 60, the concrete placed in the concrete layer 40 is fluidity It is preferred to consist of good self-filling concrete. In addition, the concrete poured into the concrete layer 40 may be configured to reduce the weight of the entire composite floor plate by applying high-performance lightweight concrete.

In addition, as shown in Figure 6, after the concrete layer 40 is cast and placed in the mold the bottom plate prepared in advance in the factory in the unit length, the space between the bottom plate of the unit length adjacent to the upper side of the mold In the field, the concrete is poured to perform the joint construction of the prefabricated floor plate in unit length.

A shear connector is attached to the bottom of the upper plate 60.

The shear connector is composed of a first shear connector 30 and a second shear connector 31. The first shear connection member 30 is bent end portion (30a) is formed in a J-shape and consists of a hook that is fastened to the fastening hole of the tensile resistance member. The second shear connector 31 is composed of a stud head 31a is installed.

Conventional composite slabs require the installation of a distribution bar on the abdomen of the inverted T-beams in order to give an even load distribution, which requires perforation and welding for installation, thereby increasing the amount of welding and complexity of the structure. In addition, the increase in the construction period and the economic aspect were quite disadvantageous. However, in the present invention, by the configuration of the first shear connecting member 30 made of a J-shaped hook on the upper plate 60, it is possible to integrate the upper plate and the tensile resistance member, the upper plate 60 Since the load-distributing effect can be transmitted to the tensile resistance member 20, it is unnecessary to install a lower power bar.

The first shear connector 30 and the second shear connector 31, at least one within the shear stress section due to the load of the vehicle acting on the upper portion of the upper plate, as shown by the dotted lines of FIGS. Configure it to be deployed. In addition, the fastening of the first shear connector and the tensile resistance member is configured to be made in the concave groove of the lower steel plate.

As described above, the shear stress caused by the load of the vehicle acting on the upper portion of the upper plate the first shear connector 30 made of the J-shaped hook and the second shear connector 31 made of the stud having the head By configuring one or more within the section, the first shear connector and the second shear connector to function as a shear stirrup to suppress the progress of the crack due to the concentrated load of the vehicle and to suppress the increase of the crack width to increase the crack width Brittle fracture can be prevented.

Meanwhile, the attachment member 50 may be further formed between the upper end of the tensile resistance member 20 and the concrete layer 40, that is, the hollow covering of the tensile resistance member embedded in the concrete layer 40. have. Here, the adhesive 50 is composed of an epoxy adhesive containing the bauxite is configured to further improve the friction performance.

As described above, by the configuration of the attachment member 50 it is possible to prevent the slip fracture between the concrete layer 40 and the tensile resistance member 20 of the reverse T-shaped steel can further increase the shear resistance. .

As described above, the partially embedded composite bottom plate 1 according to the present invention has a structure of an upper plate having a load distribution effect, a configuration of a first shear connector and a second shear connector, a lower steel plate having a corrugated shape, and bauxite. It is possible to suppress the punching shear failure by increasing the shear resistance of the bottom plate by the composition of epoxy adhesive containing.

In addition, by arranging at least one of the first and second shear connecting member within the shear stress section due to the load of the vehicle, it is possible to suppress the growth of the crack and the increase of the crack width to prevent brittle fracture due to large deflection, By increasing the resistance against slip fracture due to stress concentration phenomenon occurring in the abdomen of the tensile resistance member of the inverted T-shaped steel by the configuration to increase the composite action of the tensile resistance member and the concrete layer and to increase the punching shear strength You can.

That is, the shear force in the conventional reinforced concrete bottom plate is obtained as in the following formula (1).

V = Vc + V _dowel + V _aggregate expression (1)

Here, Vc is the shear force of concrete, V _dowel is the shear force by the _{tenon action} of compression and tensile rebar, V _aggregate is the shear force by the interlocking action of aggregate.

In contrast, the shear force of the composite bottom plate according to the present invention can be obtained as shown in the following formula (2).

V = Vc + V _aggregate + V _{f, epoxy} + V _sc + V _{s, plate} equation (2)

Here, Vc is the shear force of the concrete, V _{f, epoxy} is the frictional force, V _sc by epoxy adhesion material using the bauxite is a shear force due to the shear connector, V _{s, plate} is shear resistance due to the top plate and bottom plate, V _aggregate Means shear force due to the engagement of the aggregate.

In the synthetic deck of the present invention, the shear force of the concrete due to the reduction of the concrete cross-section is smaller than that of the conventional reinforced concrete deck, but the first shear connector and the second shear connector performs the function of shear stub, Not only reduces the shear force of the total member's shear resistance, but also acts as the shear reinforcement for the first and second shear connections, the shear resistance of the upper plate and the lower steel plate, and the abdomen of the tensile resistance member of the inverted T-beam. By the increase of the shear force from the frictional force of the epoxy adhesion material containing evoxite, the shear force of the entire bottom plate is increased rather than the conventional bottom plate.

In addition, the punching shear strength is greatly increased due to the use of the upper plate and the high-strength lower steel plate, the construction of the first and second shear connectors, and the epoxy adhesive containing the bauxite, compared to the conventional partially embedded composite bottom plate.

The strength enhancing effect on the structure of the compressed reinforcing bar embedded in the concrete of compression section is less than 10% and is not considered during design review. In other words, compressive steel is not a structural member that resists compressive force, but mainly resists creep and shrinkage. However, in the present invention, the upper plate is located on the upper surface of the compression part concrete, and the bending strength of the entire bottom plate is increased not only by the effect of increasing the length of the moment arm, but also by the construction of the first and second shear connectors. Since it plays the role of compressive and reinforcing bars from the synthetic behavior of, the process is simplified and construction period is reduced due to the need for the installation of compression and lifting bars, which increases the flexural strength of the composite deck.

The present embodiment merely shows a part of the technical idea included in the present invention, and modifications and specific embodiments which can be easily inferred by those skilled in the art within the scope of the technical idea included in the specification of the present invention are all Obviously, it is included in the technical idea of the present invention.

1 is a view showing a composite bottom plate according to the prior art.

2 and 3 is a view showing a partially embedded composite bottom plate according to the present invention.

4 to 6 are cross-sectional views of the partially embedded composite bottom plate according to the present invention.

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

1: Partially embedded composite bottom plate

2: mold

10: lower steel sheet

20: tensile resistance member

30: first shear connector

31: second shear connector

40: concrete layer

50: attachment material

60: upper steel sheet

Claims (8)

Composite bottom plate, A tensile resistance member supported by the mold and having a fastening hole formed at an upper end thereof; A lower steel plate having an upper end portion of the tensile resistance member inserted into and fixed and having a concave groove formed at a lower side thereof; An upper plate installed at an upper side of the lower steel plate, Concrete poured between the lower steel plate and the upper plate, Partially embedded composite bottom plate is attached to the bottom of the upper plate and provided with a shear connection material embedded in the concrete. The partially embedded composite bottom plate according to claim 1, wherein the tensile resistance member is made of steel having an inverted T shape. The partially embedded composite bottom plate according to claim 1, wherein the upper plate is made of a material which distributes the load of the vehicle acting on the upper plate in two directions. The method of claim 1, wherein the shear connector, A first shear connector formed in a J shape and comprising a hook fastened to the fastening hole of the tensile resistance member; Partially embedded composite floor plate comprising a second shear connector consisting of a stud head is installed. The method of claim 4, wherein And at least one of the first shear connector and the second shear connector are disposed within a shear stress section due to a load of the vehicle acting on the upper portion of the upper plate. The method according to claim 4 or 5, Partial embedded composite bottom plate, characterized in that the fastening of the first shear connector and the tensile resistance member is made in the concave groove of the lower steel plate. The method of claim 1, Partial embedded composite bottom plate, characterized in that the epoxy adhesion material containing bauxite is further formed between the tensile resistance member and the concrete. The partially embedded composite bottom plate according to claim 1, wherein the concrete is self-filling concrete.

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