KR20180087701A - Concrete Filled steel Tube of Aseismic Reinforcement and Method of Aseismic Reinforcement for Existing Building Structure using the Same - Google Patents

Abstract

The present invention relates to a seismic reinforcement CFT pole, and a seismic reinforcement method of an existing building using the same. The seismic reinforcement CFT pole comprises: a first unit member; a second unit member combined with the first unit member; a basic anchor bolt mounted to protrude inwardly from the first unit member or the second unit member; and concrete poured in an inner space of the first unit member and the second unit member. The seismic reinforcement method of an existing building using the seismic reinforcement CFT pole comprises: a first unit member fixing step of fixing the first unit member with a chemical anchor at a construction position; a second unit member combining step of fixing and combining the second unit member to the first unit member by a basic anchor bolt or by welding; and a concrete pouring step of pouring concrete into the space formed by the first unit member and the second unit member. The present invention can effectively increase ductility of the pole, be simple in preparation of construction and construction work, increase effects to reinforce rigidity, strength and ductility, and solve discontinuity of power transfer through a continuous reinforcement structure of not only the pole but also the foundation part of the pole.

Description

Technical Field [0001] The present invention relates to a seismic retrofit CFT column and an existing seismic retrofit method using the same,

The present invention relates to an anti-seismic CFT column and an existing seismic retrofitting method using the same, more particularly, to increase the confining effect of the inner concrete to effectively exhibit ductility, to adjust the concrete confining stress according to the method of construction, And to an earthquake-proof reinforcement method for existing buildings using the CFT columns.

In general, the design of various buildings is accompanied by earthquake-resistant design that can withstand earthquakes. Since applying the earthquake-resistant design regulations in the Building Code of 1990, the earthquake-related regulations have been revised . Recently, as the earthquake on the Korean Peninsula becomes more real, the regulations are being strengthened.

However, the buildings constructed prior to the introduction of the seismic design regulations are not designed and constructed without considering the effects of the earthquake, and the seismic performance is not exhibited properly due to the deterioration of the damage due to the increase in the number of public years.

In other words, it is recognized that earthquakes frequently occurring in neighboring countries on the Korean peninsula and their huge damage to life and property damage can not be said to be safe from earthquakes in Korea. Recently, There is a perception that reinforcement is necessary.

At present, more than 80% of existing buildings in Korea are defenseless against earthquakes, and especially in the case of school buildings, it can be said that it is even worse. Therefore, the seismic retrofitting method is applied to the existing buildings which are not considered or have insufficient seismic design.

As a method of reinforcing the pillars of existing buildings using reinforced concrete pipe columns (CFT, Concrete Filled Steel Tube) as a method of reinforcing the pillars of the building of the seismic retrofitting method, there is known a Korean Patent No. 10-1253519 Quot;

However, the conventional CFT column as described above has a problem in that when the lateral load is applied under a compressive load, the transverse expansion restraint is not effective, thereby causing a drastic drop in the yield strength after the maximum yield stress. The prior art has an advantage of increasing stiffness and proof strength but has a problem of low ductility reinforcement effect. In addition, there is a disadvantage that it is difficult to integrate each pipe because the possibility of mutual slip occurs between the external pipes and the concrete inside.

Conventionally, the seismic retrofitting method has a problem in that it is merely reinforced with respect to the column, and since there is no reinforcement in the base portion, there is a discontinuity in the transmission of the upper force. That is, there is a problem that the effect of the seismic strengthening is deteriorated because stress is concentrated at this portion because there is a non-reinforced portion in the maximum bending moment interval.

 Typically, columns used in construction work include reinforced concrete, steel frames (mainly H-shaped, round steel, square steel), and concrete filled steel tubes (CFT).

Among them, the CFT is a structure in which a reinforcing plate is welded to a joint between a column and a beam, and the inside of the column is filled with concrete. As a structural theory, it is known that CFT is the most reasonable column. This is because the tensile strength in the circumferential direction of the steel sheet surrounding the outermost part of the cross section is large, so that when the column receives excessive compressive force, the transverse deformation damage of the column is suppressed by the concrete filled therein.

CFT is an abbreviation of Concrete Filled Steel Tube. It is a concrete filled steel pipe filled with concrete in a round or square shaped steel pipe. CFT is a structure in which CFT is applied to a column member as a main component of a frame to resist high axial force. The CFT structure has excellent performance in various aspects such as fire resistance and construction as well as structural aspects such as rigidity, proof strength and deformation by restraining concrete by steel pipe.

The CFT structure can reduce the local buckling of the steel pipe by increasing the compressive strength of the steel pipe by restraining the concrete. The concrete can greatly improve the strength, fire resistance, workability, It is very economical in terms of points.

Korean Patent No. 10-0684931 and Korean Patent No. 10-1367626 are disclosed as related arts of the conventional CFT structure. Korean Patent No. 10-0684931 discloses a steel member having a circular or square tube shape in which a plurality of unit members are assembled so as to have an inner closed hollow cross section, And a bending portion bent from the both ends of the forming portion and the surface forming portion toward the inside of the tube so as to form a plurality of unit members, the bending portions being arranged in contact with each other, will be.

Korean Patent Registration No. 10-1367626 discloses a method of manufacturing a plurality of longitudinal unit members by bending an iron plate and having a body portion bent in an L shape and a further bent end portion inward from both ends of the body portion, A second step of manufacturing a partially reinforced steel pipe while joining a reinforcing plate to the first unit member; a second step of manufacturing a partially reinforced steel pipe by joining a reinforcing plate to the first unit member; And a third step of filling the CFT column with an inner diaphragm.

However, according to the related art of the conventional CFT structure thus configured, the slip occurring in the actual pipe and the inner concrete is structurally weak in the integrated structure, and the ductility after the maximum strength is greatly increased It does not. In addition, since the bending member in a bent state at the factory is used, the size of the binding force can not be freely adjusted at the time of construction, and the number of bending is increased even when bending at the factory, there was.

1. Korean Registered Patent No. 10-1253519 (Registered on Apr. 2013.) 2. Korean Patent No. 10-0684931 (Registered on Feb. 23, 2007) 3. Korean Patent No. 10-1367626 (Registered on Feb. 20, 2014)

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a method of improving seismic performance against lateral loads such as earthquakes by increasing the confinement effect of inner concrete and preventing slippage between pipes and concrete It is possible to increase the ductility of the column effectively and to adjust the size of the restraint force freely according to the construction. It is possible to construct the CFT column with the seismic strengthening CFT which is easy to prepare and construct construction by reducing the number of bending when bending at the factory. And to provide a seismic retrofitting method for buildings.

Another object of the present invention is to provide an earthquake-proof CFT column that solves the discontinuity of force transmission through a continuous reinforcing structure for a column base as well as columns, and an earthquake-proof reinforcement method for existing buildings using the same.

In order to achieve the above object, an anti-seismic reinforced CFT column according to a first embodiment of the present invention includes a first face forming portion having a C shape and a first bent portion bent inwardly from both ends of the first face forming portion, A first unit member, a second unit member, a second unit member having a second bent portion bent inwardly from both ends of the c-shaped second surface forming portion and the second surface forming portion and coupled to the first unit member, A first unitary member or a second unitary member, and the second unitary member includes a first unitary member and a second unitary member. The first unitary member and the second unitary member protrude into the first unitary member or the second unitary member. .

The base anchor bolt is fixed to the end of the first bending portion and the second bending portion by an anchor nut which is in close contact with the outer surface of the first bending portion and the outer surface of the second bending portion. The basic anchor bolt is fixed to an end of the first bent portion and the second bent portion by an anchor nut which is in close contact with the outer surface of the first bent portion and the outer surface of the second bent portion, . Anchor anchor nut for increasing the anchor effect (restraining effect) can be fitted to the end of the basic anchor bolt when the concrete is poured.

An anchor hole through which the chemical anchor bolt is fitted is formed in the first surface forming portion of the first unit member. And a reinforcing anchor bolt is provided in the second surface forming portion of the second unit member to reinforce the concrete when the concrete is placed in the second unit member. Anchor nuts can be inserted into reinforced anchor bolts at the ends of reinforced anchor bolts to increase the anchor effect (restraining effect) at the time of pouring concrete. The anchor nut of the reinforcement part may be in the form of a nut bent at both ends.

The seismic-strengthening CFT column of the second embodiment of the present invention comprises a first unitary member having a first surface-forming portion having a c-shape and a first bent portion bent inwardly at both ends of the first surface-defining portion, A second unit member having a second bending portion and a second bending portion bent inwardly at both ends of the second surface forming portion and connected to the first unit member; A basic unit bolt fixed to the flange of the first surface forming part and the second surface forming part so as to protrude into the inner space of the first unit member and the second unit member and serving as an anchor, And the concrete inserted in the inner space of the second unit member.

A method for constructing a CFT column using an anti-seismic reinforced CFT column using an anti-seismic reinforced CFT column according to the present invention is a method for constructing a CFT column with a first unit member fixed to a construction site by a chemical anchor step; A second unit member engaging step of securing and coupling the second unit member to the first unit member with a basic anchor bolt or welding; And a concrete casting step of casting concrete in a space formed by the first unit member and the second unit member.

According to the seismic strengthening CFT column according to the present invention and the seismic retrofitting method of existing buildings using the same, the restraint effect of the inner concrete for improving the seismic performance against lateral loads such as earthquakes is increased and the slip of each pipe and concrete is prevented It is possible to increase the ductility of the column effectively and to adjust the size of the binding force freely according to the construction. It is easy to prepare and construct the construction by reducing the number of bending when bending at the factory. Increases the effect of reinforcement.

According to the present invention, not only the reinforcement of the column but also the continuous reinforcement structure with respect to the column base can solve the discontinuity of force transmission.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a state in which an earthquake-proof reinforced CFT column according to a first embodiment of the present invention is installed in a construction column portion; FIG.
2 is an exploded perspective view showing a steel frame of an earthquake-proof CFT column of FIG. 1;
3 is a perspective view showing another example of the reinforcing portion of the anchor nut of FIG.
4 is a perspective view showing another example of the reinforcing portion of the anchor nut in Fig.
5 is a perspective view showing a state in which a first unitary member in contact with a construction base portion of the first unitary member of Fig. 1 is fixed to a construction unit;
6 is a view showing a state in which an anti-seismic reinforced CFT column according to a second embodiment of the present invention is anchored to a construction column portion.
7 is an exploded perspective view showing the first unit member and the second unit member of the seismic-strengthening CFT column of Fig. 6 separately.
8 is a flowchart showing an existing seismic strengthening method using an earthquake-proof CFT column according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that, in the drawings, the same components are denoted by the same reference symbols as possible. Further, the detailed description of known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, some of the components in the drawings are exaggerated, omitted, or schematically illustrated.

FIG. 1 is a view showing a state in which an anti-seismic reinforced CFT column according to a first embodiment of the present invention is anchored to a construction column, and FIG. 2 is an exploded perspective view showing a columnar structure of the anti-seismic reinforced CFT column of FIG. As shown, the seismic strengthening CFT column 100 according to the first embodiment of the present invention includes a first unit member 110, a second unit member 120, and a basic anchor bolt 130.

The first unit member 110 includes a first face forming portion 111 having a c-shape and a first bent portion 112 bent inward from both end portions of the first face forming portion 111, to be. A plurality of anchor holes 113 are formed in the web of the first surface forming part 111 so that the chemical anchor bolts 140 are inserted into the construction pillar CP at the time of construction. At the end of the first bent portion 112, a through hole 114 through which the basic anchor bolt 130 is inserted is formed.

The second unit member 120 includes a second face forming part 121 and a second face forming part 121. The second unit part 120 includes a second face forming part 121 and a second face forming part 121, to be. A plurality of anchor holes 123 are formed in the web of the second surface forming portion 121 to receive the reinforcing anchor bolts 150 that serve as an anchor when the concrete CR is laid. At the end of the second bending portion 122, a borehole 124 into which the basic anchor bolt 130 is fitted is formed.

The first unit member 110 and the second unit member 120 are brought into close contact with each other so that the outer surface of the boundary portion is joined to the welded portion W by welding before or after being fixed to the base anchor bolt 130. The through-holes and the through-holes of the first unit member 110 and the second unit member 120 may be formed on the opposite sides.

The basic anchor bolts 130 are connected to the outer surfaces of the first bending portion 112 and the second bending portion 122 by contacting the outer surfaces of the first bending portion 112 and the second bending portion 122, CR) It serves as an anchor when pouring. Since the basic anchor bolt 130 is formed in a T shape together with the first bent portion 112 and the second bent portion 122, when the inner concrete due to the upper load expands, the concrete is effectively restrained and the slip of the concrete pipe Thereby effectively increasing the ductility.

The basic anchor bolt 130 is fixed by an anchor nut 131 or 131 'which is in close contact with the outer surface of the first bent portion 112 and the outer surface of the second bent portion 122. The additional anchor nut for increasing the anchor effect can be fitted to the end of the basic anchor bolt 130 when the concrete CR is poured. The additional anchor nut is formed to be similar to an anchor nut to be described later, which is coupled to the reinforcement anchor bolt 150. The additional anchor nut is formed in a T shape together with the basic anchor bolt 130, effectively restraining the concrete (CR) when the inner concrete expands due to the upper load, and preventing the slip of each pipe and concrete, effectively increasing the ductility.

The chemical anchor bolt 140 is a bolt which is anchored by bonding a bolt with a resin-based adhesive. The chemical anchor bolt 140 is embedded in the construction pillar CP by a resin system and then fixed by the anchor nut 141 to the first unit member 110 fitted into the anchor hole 113.

The reinforcing anchor bolt 150 is a bolt formed with a head portion 150a which is engaged with the anchor hole 123 formed in the web of the second unit member 120 and is engaged with the outer side of the second unit member 120. The anchor nut 151 To the web of the second unit member 120. [ Anchor nuts 152 for reinforcing the anchor effect (restraining effect) are fitted to the ends of the reinforcing anchor bolts 150 when the concrete CR is poured. The reinforcement portion anchor nut 152 is formed in the form of a rectangular rod or a strip. Since the reinforcement anchor nut 152 is formed in a T shape together with the reinforcement anchor bolt 150, it effectively restrains the concrete (CR) when the inner concrete is expanded due to the upper load and prevents the slip of each pipe and concrete, .

3 is a perspective view showing another example of the reinforcing portion of the anchor nut in Fig. The reinforcing portion of the anchor nut 252 of Fig. 3 is a strip or rod having a wing portion 252a bent at both ends thereof, and is shaped like a butterfly nut. The reinforcing portion anchor nut 252 facilitates assembly of the anchor nut and further enhances the constraining effect along the bending direction. The reinforcing portion anchor nut 252 may be used in the opposite direction as shown in FIG. 3 (b), or may have various other shapes as shown in FIG. 3 (c).

4 is a perspective view showing another example of the reinforcing portion of the anchor nut in Fig. The anchor nut 352 of the reinforcement portion of Fig. 4 has a wing portion 352a formed in a cross shape and bent at each end thereof. The reinforcing portion anchor nut 352 makes it easier to assemble the anchor nut and further enhances the restraining effect along the bending direction.

5 is a perspective view showing a state in which the first unit member 310, which is in contact with the construction base portion CB, is fixed to the installation portion in the first unit member of FIG. The base unit 315 is attached to the lower end of the first unit member 310 so as to be closely attached to the base portion CB and fixed by the chemical anchor bolts 160. The outer surface of the web of the first surface forming portion of the first unit member 310 is fixed to the construction starting portion CP by the chemical anchor bolt 140. In the structure in which the chemical anchor bolts are installed on the column base portion CB by using the first unit portion 310 material, the force transmission is continued to enhance the base portion reinforcement effect.

6 is a view showing a state in which an anti-seismic reinforced CFT column according to a second embodiment of the present invention is anchored to a construction column portion. 7 is an exploded perspective view showing the first unit member and the second unit member of the seismic-strengthening CFT column of Fig. 6 separately.

In the seismic-strengthening CFT column of the second embodiment, the first surface forming portion 211 having a c-shape and the first unitary member having the first bending portion 212 bent inward at both ends of the first surface forming portion 211, A second unit member 220 having a second bent portion 222 bent inwardly from both ends of the second surface forming portion 221 and the second surface forming portion 221 in a C shape, The first bent portion 212 and the second bent portion 222 are welded to each other by welding and the flange of the first surface forming portion 211 and the second surface forming portion 221 is provided with a first unit member And a basic anchor bolt 230 serving as an anchor when the concrete CR is installed in the inner space of the first unit member 210 and the second unit member 220.

The first unit member 210 and the second unit member 220 are brought into close contact with each other so that the outer surface of the boundary portion is joined to the welded portion W by welding before or after being fixed by the basic anchor bolts 230. The basic anchor bolt 230 is an anchor bolt similar to the reinforcing anchor bolt 150 of FIG.

An anchor hole 213 is formed in the web of the first surface forming portion 211 to sandwich the chemical anchor bolt 240 (same as 140 in FIG. 1) during the construction, and the web of the second surface forming portion 221 is formed Anchor holes 223 are formed in which reinforcing anchor bolts 250 (the same as 150 in FIG. 1) are provided to reinforce concrete CR when the concrete unit CR is pushed into the second unit member 220. Anchor holes 215 and 225 are formed in the flanges of the first surface forming portion 211 and the second surface forming portion 221, respectively, to which the basic anchor bolts 230 are respectively attached.

In the second embodiment, since both the basic anchor bolt 230 and the reinforcing anchor bolt 250 are assembled to the first unit member 210 and the second unit member 220, This has the effect of simplification.

The remaining configuration of the second embodiment is the same as that of the first embodiment, and thus a detailed description thereof will be omitted.

8 is a flowchart showing an existing seismic strengthening method using an earthquake-proof CFT column according to an embodiment of the present invention. As shown in the figure, the seismic retrofitting method of an existing building using an anti-seismic reinforced CFT column includes a preparation step S110, a first unit member fixing step S120, a second unit member joining step S130, S140). Hereinafter, an example in which the earthquake-proofing CFT column 100 of the first embodiment is used will be described.

In the preparation step S110, the first unit member 110 and the second unit member 120, which are formed by burying the anchor holes in the construction column portion CP and the construction base portion CB to construct the CFT column, A bolt 130, a chemical anchor bolt 140 and a reinforcement anchor bolt 150 are prepared. The first and second unit members 110 and 120 are bent at the factory and prepared by drilling holes for inserting the anchor bolts.

The first unit member fixing step S120 is a step of fixing the first unit member 110 to the installation position (CP and the base portion CB) by the chemical anchors 140 and 160, The joining step S130 is a step of fixing the second unit member 120 to the first unit member 110 by fixing the first unit member 120 to the basic anchor bolt 130 or welding. At this time, the second unit member coupling step S130 may be first performed and the first unit member fixing step S120 may be performed. The reinforcing anchor bolts 150 may be assembled in the preparation step S110. The basic anchor bolt 130 and the reinforcement anchor bolt 150 use anchor bolts of different lengths depending on the magnitude of the constraining force and the additional anchor nut or reinforcement anchor nut 152 uses a different shape depending on the magnitude of the restraining force .

The concrete pouring step S140 is a step of pouring concrete into the space defined by the first unit member 110 and the second unit member 120. [

The basic anchor bolt 230 and the reinforcing anchor bolt 250 assembled to the first unit member 210 and the second unit member 220 are prepared in the preparation step S110 in the seismic-strengthening CFT column 200 of the second embodiment, . Also, in the assembled steel structure 200 of the second embodiment, the second unit member joining step (S130) in which the bending portions of the first unit member 210 and the second unit member 222 are butted together by welding is first applied, It is preferable to construct the one unit member fixing step (S120).

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of the present invention in order to facilitate the understanding of the present invention and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

100, 200: Seismic strengthening CFT column
110, 210, 310: first unit member 111: first surface forming part
112: first bending section 113, 123: anchor hole
114: through hole 120, 220: second unit member
121: second surface forming portion 122: second bend portion
124: open mouth mouth
130, 230: basic anchor bolts 131, 141, 151: anchor nut
140, 160, 240: chemical anchor bolts 150, 250: reinforcing anchor bolts
150a: head portion 152, 252, 352: reinforcement portion anchor nut
252a, 352a: wing portion 315: base plate
W: Welding part CP: Construction part
CB: Construction base CR: Concrete

Claims (5)

A first unit member having a first surface forming portion having a C shape and a first bending portion bent inwardly at both ends of the first surface forming portion and fixed to a mounting position;
A second unit member having a second planar forming portion and a second planar forming portion bent inwardly at both ends of the second planar forming portion and fixed to the first unit member,
The first unit member and the second unit member are connected to each other by contacting the first bent portion and the outer surface of the second bent portion to be protruded into the first unit member or the second unit member, A basic anchor bolt that acts as an anchor (restraining effect) when pouring concrete,
And the concrete embedded in the inner space of the first unit member and the second unit member. The method according to claim 1,
A first unit member having a first surface forming portion having a C shape and a first bending portion bent inwardly at both ends of the first surface forming portion and fixed to a mounting position;
A second unit member having a second planar forming portion and a second planar forming portion bent inwardly at both ends of the second planar forming portion and fixed to the first unit member,
The first bent portion and the second bent portion are welded to each other and welded to the flange of the first surface forming portion and the second surface forming portion to project into the inner space of the first unit member and the second unit member, A basic anchor bolt installed in the first unit member and serving as an anchor when the concrete is placed in the inner space of the first unit member and the second unit member,
And the concrete embedded in the inner space of the first unit member and the second unit member. The method according to claim 1 or 2,
And an additional anchor nut for increasing an anchor effect (restraining effect) is inserted into the end of the basic anchor bolt when the concrete is poured. The method according to claim 1 or 2,
And a reinforcing anchor bolt is installed in the second surface forming part to reinforce the concrete to serve as an anchor when the concrete is installed in the second unit member. Claims [1] A method of reinforcing an earthquake of an existing building using an earthquake-resistant CFT column of claim 1 or 2,
A first unit member fixing step of fixing the first unit member to a mounting position by a chemical anchor;
A second unit member coupling step of fixing the second unit member to the first unit member by fixing the first unit member with a basic anchor bolt or welding;
And a concrete pouring step of pouring concrete into a space formed by the first unit member and the second unit member. The present invention relates to an earthquake-proof reinforcement method for an existing building using an earthquake-proof CFT column

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