JP4616807B2 - Strengthening method and structure of existing pillars - Google Patents

Description

  The present invention relates to a reinforcing method for reinforcing an existing column made of reinforced concrete to improve seismic strength and a reinforcing structure thereof.

  Conventionally, as one of reinforcing methods for improving the toughness of a rectangular reinforced concrete column, there is a method of increasing the shear strength of a column by winding a steel plate around an existing column (for example, Patent Document 1). In this method, even if the concrete peels off the pillar in the event of an earthquake, the peeled piece is constrained by the wound steel plate and does not peel off from the pillar, so the toughness of the pillar is abrupt. To prevent it from dropping.

  However, it has been pointed out that the reinforcement by only the winding of the steel plate is easily deformed in the direction in which the rolled steel plate swells outward at the upper and lower ends of the column, and the effect of restraining the column is insufficient. If the lower end of the rolled steel plate is deformed in the direction of swelling during an earthquake, the restraining effect may be reduced at the deformed portion, and a small piece of concrete peeled off from the deformed portion may be peeled off. May cause a significant decrease in toughness. In particular, when the cross-sectional dimensions of the columns are increased, the restraining effect tends to be more likely to decrease.

JP 2005-220699 A

  Therefore, the present invention has been made for the purpose of solving the above-mentioned conventional problems, and can suppress the deformation of the end of the rolled steel sheet, maintain the restraining effect of the concrete, and improve the toughness performance. The present invention provides a method for reinforcing an existing pillar and a reinforcing structure thereof.

  In order to achieve the above object, the present inventor has intensively studied, and it is desired to reinforce the deformable upper and lower parts of the wound steel sheet wound so as to surround the existing pillar. If the reinforcing steel material to be used has a fixed plate and a stiffening plate perpendicular to the fixed plate, and the fixed plate is fixed so as to restrain the periphery of the wound steel plate, the end of the rolled steel plate The knowledge that can be effectively reinforced.

  Therefore, the present invention adopts as a solution means in a reinforcing method for winding and reinforcing a steel plate around an existing column made of reinforced concrete, a winding step of winding the steel plate so as to surround the existing column, a fixing plate, and the fixing And a restraining step of fixing a reinforcing steel material made of a stiffening plate perpendicular to the plate so as to restrain the upper and / or lower part of the wound steel plate via the fixed plate. According to such a reinforcing method, it is possible to effectively reinforce the periphery of the upper part and / or the lower part of the wound steel plate that is easily deformed. The reinforcing steel material is preferably L-shaped steel, but is not necessarily limited to L-shaped steel.

  In this reinforcing method, it is preferable that in the winding step, the wound steel plate is wound around an existing column so that a gap is formed between the upper end portion of the rolled steel plate and the beam and the lower end portion of the floor slab. Furthermore, in this reinforcing method, in the winding step, the wound steel plate is wound with a gap between the side surfaces of the existing columns, and the gap is filled with mortar, whereby the rolled steel plate and the existing columns are filled. Are preferably integrated.

  Further, the reinforcing structure according to the present invention adopts as a solution means that in a reinforcing structure in which a steel plate is wound around an existing column made of reinforced concrete to reinforce the steel plate so as to surround the existing column, A point in which a reinforcing steel material made of a stiffening plate perpendicular to the fixed plate is fixed to the upper and / or lower portion of the wound steel plate via the fixed plate so as to restrain the periphery of the wound steel plate. It is in. Such a reinforcing structure effectively reinforces the periphery of the upper and / or lower part of the wound steel plate that is easily deformed. Here, it is preferable to use L-shaped steel as the reinforcing steel material, but it is not necessarily limited to L-shaped steel.

  In this reinforcing structure, it is preferable that the wound steel plate is wound around an existing column such that there is a gap between the upper end of the steel plate and the beam and the lower end of the steel plate with the floor slab. Furthermore, as this reinforcing structure, the wound steel plate is wound with a gap between the side of the existing pillar and a filler such as mortar is applied to the gap to integrate the wound steel plate and the existing pillar. It is preferable to have a structure as described above.

  Furthermore, in this reinforcing structure, it is preferable to further provide a protective material that is fixed to the stiffening plate and that smoothly connects the top surface and the floor surface of the stiffening plate. The upper portion of the floor slab is removed in advance, the lower end of the rolled steel plate is disposed below the floor surface, and the upper surface of the stiffening plate of the reinforcing steel material is substantially flush with the floor surface. It is preferable to provide a flat protective material on the upper surface of the stiffening plate. In the case of this structure, it is more preferable to fill the lower space of the protective material with a flexible material.

  According to the reinforcement method and the reinforcement structure of the existing pillar according to the present invention, the steel plate is wound up so as to surround the existing pillar, and the reinforcement includes a fixing plate and a stiffening plate perpendicular to the fixing plate. Since the steel material is fixed so as to constrain the periphery of the upper and / or lower part of the wound steel plate via the fixed plate, the upper and / or lower part of the wound steel plate can be constrained by the reinforcing steel material. . Therefore, it is possible to suppress the deformation of the upper and lower ends of the wound steel plate that is easily deformed during an earthquake, maintain the restraining effect of the existing columns, and increase the toughness of the columns. That is, since the reinforcing steel materials are concentrated on the column head and the column base of the rolled steel plate that becomes the plastic hinge region, the bending plastic deformation angle (Rmp) of the column is increased as compared with the reinforcement using only the rolled steel plate, The deformation performance of the pillar can be dramatically improved.

  In addition, the upper and lower ends of the rolled steel sheet are rolled up at the time of an earthquake by winding the wound steel sheet around an existing column so that the upper end is between the beam and the lower end is between the floor slab. Prevents buckling deformation due to contact with beams and floor slabs, and maintains the restraint effect of existing columns.

  In addition, a structure in which the wound steel sheet is wound with a gap between the side of the existing pillar and filled with reinforcing mortar so that both the wound steel sheet and the mortar constrain and reinforce the existing pillar. And demonstrates a better reinforcing effect.

  Further, if a protective material is attached to the stiffening plate, the stiffening plate is covered with the protective material, so that the stiffening plate can be prevented from being obstructed during passage.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. 1 to 3 are conceptual diagrams showing a method of reinforcing an existing pillar according to the present invention. FIG. 1 is a perspective view showing a state in which a reinforcing member is assembled to the existing pillar. FIG. FIG. 3 is a perspective view showing a state before the reinforcing member is assembled, and FIG. 3 is a side view showing a state in which an existing column is reinforced. This reinforcing method is an existing existing pillar that is not connected to a wall or the like, and is for reinforcing a rectangular reinforced concrete pillar such as a square pillar, for example. The steel plate 2 is wound and restrained so as to surround the existing column 1, and the reinforcing steel material 3 is surrounded by the upper column head portion and the lower column base portion of the rolled steel plate 2 so as to surround the existing column 1, respectively. Reinforce by attaching. As shown in the figure, the reinforcing steel material 3 is a reinforcing steel material provided with a fixing plate 3a and a stiffening plate 3b perpendicular to the fixing plate 3a. For example, the reinforcing steel material 3 is composed of an angle L-shaped angle steel (L-shaped steel). The However, the present invention is not limited to L-shaped steel, and may be H-shaped steel, T-shaped steel, or other steel materials other than L-shaped steel.

Four reinforcing steel members 3 are arranged on each of the column head portion and the column base portion of the wound steel plate 2, and each fixing plate 3 a is fixed to the surface of the wound steel plate 2, and the reinforcing steel materials 3 adjacent to each other in the circumferential direction. Also, the periphery of the upper and lower portions of the wound steel plate 2 is restrained by fixing. For this reason, the stiffening plate 3 b forms a substantially horizontal flange portion that protrudes perpendicularly from the side surface of the wound steel plate 2 over the entire circumference of the wound steel plate 2. This stiffening plate 3b exhibits the effect of suppressing deformation of the wound steel plate 2 against the horizontal force applied from the inside of the wound steel plate 2 during an earthquake. In addition, although the case where the reinforcing steel material 3 is provided in both the upper part and the lower part of the wound steel plate 2 is illustrated in the illustrated example, the other reinforcing steel material is omitted when only one of the upper part and the lower part may be reinforced. It doesn't matter.

  The two wound steel plates 2 have a thickness of about 4.5 to 9 mm, for example, and the bent portion is formed with a bending radius of about three times the plate thickness or more. A plate 4 is provided on the back side of the joining portion of the two rolled steel plates 2 when the existing pillar 1 is wound, and each of the rolled steel plates 2 is welded to the plate 4 to be installed. It is fixed in a state of surrounding the pillar 1. However, the winding steel plate 2 is not necessarily fixed by welding, but may be fixed by fastening bolts and nuts, or other fixing methods may be employed.

  In this way, the wound steel plate 2 that surrounds and fixes the existing pillar 1 does not contact the lower end of the beam 5, as shown in FIG. It arrange | positions so that it may have the clearance gap G of about 15-30 mm between them, for example. Similarly, the lower end of the wound steel plate 2 is also arranged so as not to contact the floor surface 6 but to have a gap G of, for example, about 15 to 30 mm with the floor surface 6. These gaps G are for preventing the upper and lower ends of the wound steel plate 2 from contacting the lower end of the beam 5 and the floor slab when the column 1 is deformed by receiving a horizontal force due to the earthquake, It is provided for the purpose of preventing buckling or local deformation from occurring when the rolled steel sheet 2 comes into contact with a beam or a floor slab.

  Further, the inner side of the wound steel plate 2 is not in close contact with the side surface of the existing column 1 but is fixed with a slight gap between the side surface of the column. FIG. 4 shows a cross-sectional view of the column 1 wound with the wound steel plate 2, in order to ensure a certain gap 7 between the wound steel plate 2 and the existing column 1 inside the wound steel plate 2. The separator 8 is provided. Moreover, the bolt 9 which fixes the wound steel plate 2 to the existing pillar 1 is hit | damaged from the outer side of the wound steel plate 2 to the side surface of the existing pillar 1 as needed, and the clearance gap 7 inside the wound steel plate 2 is larger than necessary. To prevent becoming.

The reinforcing mortar 10 is filled into the gap 7 formed inside the wound steel plate 2. The filling mortar 10 is 21 N / mm ² or more and has a concrete strength higher than that of the existing pillar 1. Further, in order to sufficiently spread the mortar over the entire gap 7 inside the wound steel plate 2, the filling mortar 10 has a high fluidity. When the wound steel plate 2 is fixed to the existing column 1 with the bolt 9, the bulging of the rolled steel plate 2 is prevented when the mortar 10 is filled in the gap 7 between the wound steel plate 2 and the existing column 1. The mortar 10 can be filled almost uniformly from the column base to the column head. And when the filling mortar 10 solidifies, the filling mortar 10 and the wound steel plate 2 reinforce the entire existing pillar 1.

  Further, before and after the filling of the mortar 10, the above-described reinforcing steel material 3 is fixed to the upper and lower portions of the wound steel plate 2. For example, the reinforcing steel material 3 is attached by welding the fixing plate 3a to the wound steel plate 2, but the attachment of the reinforcing steel material 3 is not necessarily limited to welding, and may be fixed by fastening bolts and nuts. However, other fixing methods may be employed. Further, the reinforcing steel materials 3 adjacent to each other in the circumferential direction are also fixed in a connected state by welding or other methods. Therefore, the reinforcing steel materials 3 provided at the upper part and the lower part of the wound steel plate 2 are fixed in an annular shape so as to surround the wound steel plate 2, and are restrained and reinforced by the upper and lower ends of the existing pillar 1. Even if the existing pillar 1 is greatly deformed at the time of the earthquake, the restraint effect of the existing pillar 1 is maintained by suppressing the deformation of the wound steel plate 2. Therefore, the toughness of the entire column is increased. The reinforcing steel material 3 may be attached to the upper and lower parts of the wound steel plate 2 in advance prior to winding the wound steel plate 2 around the existing column 1.

  FIG. 5 is a longitudinal cross-sectional view showing an example of an attachment mode of the reinforcing steel material 3 by this method. As illustrated, the reinforcing steel material 3 is disposed between the beam 5 and the floor slab 6 with a gap t therebetween. This gap t is provided for the same purpose as the gap G provided at the upper and lower ends of the wound steel plate 2, and even when the existing column 1 is deformed due to a horizontal force due to an earthquake, the reinforcing steel material 3 is made of a beam. This prevents contact with the lower end of 5 and the floor slab, and suppresses a reduction in restraining force due to deformation. In the illustrated example, the reinforcing steel material 3 fixed to the upper part of the wound steel plate 2 is arranged in an inverted L shape so that the stiffening plate 3b is located at the upper edge of the fixed plate 3a. The fixed reinforcing steel material 3 shows a case where the stiffening plate 3b is arranged in a regular L shape so that the stiffening plate 3b is positioned at the lower edge of the fixed plate 3a, but is not limited to this mode. In this way, the reinforcing steel material 3 fixed to the upper part and the lower part of the wound steel sheet 2 is reinforced so that the lateral restraining force at the upper and lower ends of the wound steel sheet 2 is increased by restraining the wound steel sheet 2 in the circumferential direction. Therefore, it is possible to prevent the wound steel plate 2 from buckling and the lateral restraining force from being lowered during an earthquake, and to prevent the toughness of the existing column 1 from being lowered. Therefore, when compared with the reinforcing method using only the wound steel plate 2, the toughness of the column is remarkably improved.

  In the present embodiment, as shown in FIG. 5, a peeling prevention plate 2 b is provided at the lower end portion of the wound steel plate 2. That is, in the event of an earthquake, the mortar 10 filled inside the wound steel plate 2 may peel off, and the peeled mortar piece is prevented from peeling off from the inside of the wound steel plate 2. A peeling prevention plate 2b is provided in order to keep the inside densely at all times. Therefore, the peeling prevention plate 2b is preferably provided so as to close the gap inside the lower end of the wound steel plate 2. This peeling prevention plate 2b may be formed by bending the lower end portion of the wound steel plate 2, or may be formed by fixing another narrow plate by welding or the like. Thereby, even if the filling mortar 10 peels inside the wound steel plate 2 in the event of an earthquake, the peeled pieces will not fall from the lower end of the wound steel plate 2. Therefore, the inside of the wound steel plate 2 is not hollowed out, and the restraining effect of the existing pillar 1 by the wound steel plate 2 is favorably maintained. However, such a peeling prevention plate 2b is not essential, and a structure in which the peeling prevention plate 2b is omitted may be employed.

  By the way, in the above-mentioned method, the lower end of the wound steel plate 2 is attached to a position higher than the floor surface 6, and the stiffening plate 3 b of the reinforcing steel material 3 is also attached to a position higher than the floor surface 6. Therefore, the stiffening plate 3b protruding at right angles from the wound steel plate 2 at the column base part becomes an obstacle at the time of passage, etc., and the pedestrian's foot may hit the stiffening plate 3b. As shown in FIGS. 6 to 8, the stiffening plate 3b is preferably provided with a protective material.

  FIG. 6 shows a configuration example in which the reinforcing members 3 of the column base portions, particularly the upper surfaces of the stiffening plates 3b are arranged so as to be flush with the floor surface 6. In this configuration, the floor slab around the existing pillar 1 is previously removed by digging about several centimeters from the floor surface, and the lower end of the rolled steel plate 2 is disposed at a position below the floor surface 6 and is reinforced. It attaches so that the upper surface of the stiffening plate 3b of the steel material 3 is substantially flush with the floor surface 6. At this time, it is preferable to provide a gap so that the tip of the stiffening plate 3b does not contact the floor slab, but the gap is made as small as possible. And the floor finishing material 15 used as a protective material is provided in the upper surface of the stiffening board 3b of this reinforcement steel material 3. FIG. The same floor finishing material 15 as the floor finishing material such as a carpet laid on the floor surface 6 may be extended on the stiffening plate 3b. If part of the floor slab of the column base part is removed in this way and this reinforcement method is performed, the reinforcing steel material 3 of the column base part will not obstruct the passage and the like, and the area around the existing column 1 can be used effectively. It becomes like this. When a part of the floor slab is removed as shown in FIG. 6, the removed portion 14 is flexible such as styrofoam or urethane that does not restrain the displacement of the reinforcing steel material 3 or the rolled steel sheet 2 during an earthquake. The material may be filled.

  Next, FIG. 7 shows a configuration example in which the protective material 11 is provided on the stiffening plate 3b of the column base portion without removing the floor slab. The protective material 11 is a plate-like body that is formed of a flexible material such as rubber or resin and has a cross-sectional “h” shape. The protective material 11 is fixed to the upper surface of the stiffening plate 3 b and smoothly covers the floor surface 6. Arranged to connect. The reason why the protective material 11 is formed of a flexible material such as rubber or resin is that the protective material 11 itself does not restrain the displacement of the column 1 or the rolled steel plate 2 during an earthquake. The protective material 11 is not formed of a flexible material, but, for example, by setting the strength of the joint portion with the stiffening plate 3b low, the joint portion is easily broken during an earthquake, and the column 1 or the winding You may comprise so that the displacement of the standing steel plate 2 may not be restrained. In addition, when the protective material 11 is arrange | positioned like FIG. 7, the flexible material which does not restrain the displacement of the reinforcing steel material 3 and the winding steel plate 2 at the time of an earthquake like styrofoam or urethane in the lower space 12 of the protective material 11 The material may be filled. If the protective material 11 is provided on the stiffening plate 3b in this way, the stiffening plate 3b is covered with the protective material 11, so that there is no possibility that the foot of the pedestrian directly hits the stiffening plate 3b during passage.

  Further, FIG. 8 shows a configuration example in which the upper part of the floor slab around the existing pillar 1 is removed and the protective material 13 is arranged so as to be substantially flush with the floor surface 6. That is, as in the case of FIG. 6, the floor slab around the existing pillar 1 is removed by digging up about several centimeters in advance, and the lower end of the wound steel plate 2 is disposed at a position below the floor surface 6. The reinforcing steel plate 3 is attached so that the upper surface of the stiffening plate 3b is substantially flush with the floor surface 6. And the flat protective material 13 is attached to the upper surface of the stiffening plate 3b of this reinforcing steel material 3. Even in this case, the protective member 13 is preferably made of a flexible material such as rubber or resin so as not to restrain the displacement of the column 1 or the rolled steel plate 2 during an earthquake, but the bonding strength with the reinforcing steel material 3 is weakened. By doing so, you may make it not restrain the displacement of the pillar 1 or the wound steel plate 2. The removed portion 14 from which a part of the floor slab is removed may be filled with a flexible material such as styrofoam or urethane that does not restrain the displacement of the reinforcing steel material 3 and the wound steel plate 2 during an earthquake. Even in the case of FIG. 8, the reinforcing steel material 3 in the column base portion does not hinder traffic and the like, and the surroundings of the existing column 1 can be effectively utilized.

  As mentioned above, although one Embodiment of this invention was explained in full detail, this invention is not limited to what was mentioned above. For example, in the above-described example, the case where the existing pillar 1 to be reinforced is a quadrangular pillar is shown, but the present invention is not limited thereto, and may be another polygonal pillar or a cylinder. May be. Moreover, although the case where the existing pillar 1 is wound up with the two wound steel plates 2 was shown in the above-mentioned example, the number of the wound steel plates is arbitrary. Furthermore, in the above example, it is assumed that the existing pillar 1 is an independent pillar that is not connected to a wall or the like, but even if the wall is connected to the existing pillar 1, Since it is possible to restore the wall again after removing the wall and applying the above-mentioned reinforcement, the existing pillars to be reinforced in the present invention are not necessarily limited to independent pillars. .

It is a perspective view which shows the state which assembled | attached the reinforcement member with respect to the existing pillar. It is a perspective view which shows the state before assembling each reinforcement member with respect to the existing pillar. It is a side view which shows the state which reinforced the existing pillar. It is a cross-sectional view of the existing pillar which wound the wound steel plate. It is a longitudinal cross-sectional view which shows the state which fixed the reinforcement steel material. It is an expanded sectional view which shows the aspect which attached the reinforcing steel material and the floor finishing material to the column base part which removed the floor slab partially. It is an expanded sectional view which shows the aspect which attached the protective material to the reinforced column base part. It is an expanded sectional view which shows the aspect which attached the reinforcing steel material and the protective material to the column base part which removed the floor slab partially.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Existing pillar 2 Winding steel plate 3 Reinforced steel material 3a Fixed plate 3b Stiffening plate 5 Beam 6 Floor 10 Filling mortar 11,13 Protective material 15 Floor finishing material (protective material)

Claims (7)

In the reinforcement method to reinforce a steel plate around an existing pillar made of reinforced concrete,
A winding step in which the upper end is between the beam and the lower end is between the floor slab and the steel plate is wound so as to surround the existing pillar,
A reinforcing steel material comprising a fixing plate and a stiffening plate perpendicular to the fixing plate is wound through the fixing plate with the stiffening plate having a gap between the beam and / or the floor slab . A restraining step of fixing the steel plate so as to restrain the upper and / or lower part of the steel plate;
A method for reinforcing an existing pillar, characterized by comprising: The method of reinforcing an existing pillar according to claim 1 , wherein in the winding step, the wound steel sheet is wound with a gap between the side of the existing pillar and mortar is filled in the gap. In the reinforcement structure that winds and reinforces steel plates on existing columns made of reinforced concrete,
The upper end is between the beam and the lower end is between the floor slab and the steel plate is wound up so as to surround the existing column, and the fixing plate and the fixing plate are perpendicular to each other. A reinforcing steel material made of a stiffening plate is fixed to the upper part and / or the lower part of a wound steel plate via the fixing plate, with the stiffening plate having a gap between the beam and / or the floor slab. A reinforcing structure for an existing column, which is provided so as to restrain the periphery of a wound steel plate. The reinforcing structure for an existing pillar according to claim 3, wherein the rolled steel sheet is wound with a gap between the side face of the existing pillar and filled with mortar. The reinforcing structure for an existing column according to claim 3 or 4 , further comprising a protective member that is fixed to the stiffening plate and that smoothly connects an upper surface and a floor surface of the stiffening plate. The upper part of the floor slab around the existing pillar is removed, the lower end of the rolled steel plate is disposed below the floor surface, and the upper surface of the stiffening plate of the reinforcing steel material is substantially flush with the floor surface. The reinforcing structure of an existing pillar according to claim 3 or 4 , wherein a flat protective material is attached to the upper surface of the stiffening plate. The reinforcing structure for an existing pillar according to claim 5 or 6, wherein the lower space of the protective material is filled with a flexible material.

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