JP3909488B2 - Seismic reinforcement structure of existing building and its construction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seismic reinforcement structure for an existing building having an RC frame made of RC (reinforced concrete) columns and beams, and a construction method thereof.
[0002]
[Prior art]
Conventionally, when retrofitting an existing RC or SRC structure, a method of constructing a seismic wall made of post-cast concrete in an RC frame (frame) composed of RC columns and beams has been adopted. Has been.
At that time, in order to increase the rigidity as the structure of the part where the earthquake-resistant wall was added and to secure the earthquake resistance, anchor reinforcements were buried in the four circumferences of the additional earthquake-proof reinforcement wall facing the RC frame, respectively. The seismic reinforcement wall is integrated with the RC frame.
[0003]
[Problems to be solved by the invention]
In the conventional seismic reinforcement structure of the existing building, it is an important point to integrally join the existing RC frame made of RC columns and beams and the seismic wall by the back-up. Therefore, many anchor bolts are projected inside the RC frame consisting of existing RC columns and beams, but there is noise, vibration, dust generation, etc. when drilling the anchor bolt holes. There was a problem that could not be. When drilling an anchor bolt hole, if it interferes with the existing RC column or beam main bar or shear reinforcement bar, not only the anchor bolt hole needs to be drilled, but also the anchor bolt hole There is a problem that the existing pillars and beams are damaged by drilling and the strength is lowered, especially when the strength is lowered in the column supporting the vertical load, which causes a risk of falling.
[0004]
The present invention solves the above-described problems in the prior art, and in constructing a seismic reinforcement wall inside an RC frame made of existing RC columns and beams, the inside of the RC frame made of existing RC columns and beams. There is no need to project anchor bolts, and therefore there is no generation of noise, vibration and dust associated with drilling anchor bolt holes, and there is no reduction in strength of existing RC columns and beams, An object of the present invention is to provide a seismic reinforcement structure for an existing building that can be easily and quickly constructed and a construction method thereof.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is to provide a PC wall plate having a U-shaped cross section at least at the upper and lower ends of an RC column of an existing building and built in an RC frame. At least one of the RC pillars is provided by attaching and fixing a reinforcing member having an opening directed to the wall and extending both wall surfaces forming the opening beyond the vertical wall surface of the RC pillar. In addition to reinforcing the upper and lower ends, a PC wall plate in which concrete is laid by placing wall bars and prestressing reinforcement bars inside the steel frame, is installed in an RC frame made of RC columns and beams of the existing building. The reinforcing members disposed and fixed to at least the upper and lower ends of the RC columns of the existing building and the steel frame of the PC wall plate are placed on both sides of the steel frame in the thickness direction of the PC wall plate. One end of the joining member is fixed, and the other end is connected to the extension of the reinforcing member. Portion of the vertical wall to abut and further joined by fastening by bolts and nuts, are seismic reinforcement structure of an existing building formed by disposing a filler material between the steel frame of at least RC frame inner peripheral surface and the PC wallboards .
[0006]
The invention according to claim 2 is that the reinforcing member disposed and fixed to at least the upper and lower ends of the RC column of the existing building is a steel plate, and the wall reinforcement and the prestress introduction reinforcement in the PC wall board are vertical. The existing building according to claim 1, arranged in a grid pattern in the horizontal and horizontal directions, or arranged in a grid pattern inclined with respect to the axis of the RC column of the existing building, and the filler is mortar. This is a seismic reinforcement structure.
[0007]
The invention according to claim 3 has at least the upper and lower ends of the RC column of the existing building having a U-shaped cross section and having an opening directed toward the PC wall plate built in the RC frame. And at least upper and lower ends of the RC column are reinforced by arranging and fixing reinforcing members in which both wall surfaces forming the opening extend beyond the vertical wall surface of the RC column. In the steel frame, a wall reinforcement and a prestress introduction reinforcement are placed and concrete is placed in order to prefabricate the PC wallboard, and the PC wallboard is made up of RC columns and beams of existing buildings. The reinforcing member built in the frame and disposed and fixed to at least the upper and lower ends of the RC column of the existing building and the steel frame of the PC wall plate are arranged in the thickness direction of the PC wall plate of the steel frame. One end of the joining member is fixed to both sides, and the other end of the extending portion of the reinforcing member It joins with a vertical wall surface and is fastened with bolts and nuts, and prestress is introduced by applying tension to the prestressing rebar in the PC wall plate, and at least the inner peripheral surface of the RC frame and the PC wall plate It is a construction method of the seismic reinforcement structure of the existing building characterized by arrange | positioning a filler between steel frame.
[0008]
According to a fourth aspect of the present invention, the reinforcing member disposed and fixed on at least the upper and lower ends of the RC column of the existing building is a steel plate, and the wall bars and the prestress introduction reinforcing bars in the PC wall board are vertical. The existing reinforcement according to claim 3, wherein the reinforcing material is a non-shrinking mortar, and is arranged in a grid pattern in a grid pattern in the horizontal and horizontal directions or inclined with respect to an axis of an RC column of an existing building. It is a construction method of building seismic reinforcement structure.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described according to preferred embodiments thereof.
[0010]
FIG. 1 is a front view showing a seismic reinforcement structure for an existing building according to the present invention. FIG. 2 is a cross-sectional view showing a joining state of a steel frame in a reinforcing member and a PC wall plate (wall panel) in an RC column of an existing building and a filling state of non-shrink mortar. FIG. 3 is a cross-sectional view showing an embodiment for joining PC wall plates (wall panels) to each other. FIG. 4 is a graph showing the load / deformation characteristics of the seismic reinforcement structure of an existing building according to the present invention in comparison with that of a conventional seismic reinforcement structure of an existing building.
[0011]
1 to 3, reference numeral 1 denotes a PC wall plate (precast concrete panel), which is a steel frame (in this embodiment, as shown in FIGS. 2 and 3, an H-shaped steel) 2 It is placed inside as an RC wall panel. Moreover, the PC wall board 1 is factory-produced (prefabricated) in this embodiment.
[0012]
Wall bars 13 and high-strength reinforcing bars 11 are arranged on the PC wall board 1.
As shown in FIG. 2 and FIG. 3, a screw is engraved at the end of the high-strength reinforcing bar 11 and protrudes from a hole drilled in the web portion of the steel frame 2 (H-shaped steel). It is comprised so that tension | tensile_strength may be provided by. In this embodiment, the high-strength reinforcing bars 11 and the wall bars 13 are arranged in a lattice form in parallel with the sides of the PC wall plate 1 in a vertical and horizontal direction, as shown in FIGS. The high-strength reinforcing bar 11 for PC wall plate mutual joining is covered with a sheath. Concrete is cast in this state, and is produced (prefabricated) as a PC wall board 1 (RC wall panel).
[0013]
The high-strength reinforcing bars 11 and the wall reinforcing bars 13 may be arranged in a lattice shape inclined in the PC wall board 1 and orthogonal to each other at an angle of 45 ° with respect to the side of the PC wall board 1, for example. Further, the high-strength reinforcing bars 11 may be arranged in a lattice shape in the vertical and horizontal directions parallel to the sides of the PC wall plate 1 in a lattice shape in which only the wall bars 13 are inclined.
[0014]
In order to join the PC wall plates 1 to each other, in this embodiment, as shown in FIGS. 1 and 3, the end of the high-strength reinforcing bar 11 is engraved with screws so as to become left and right screws, and the coupler 12 For example, tightening is performed by a turnbuckle, and a prestress (compressive stress) is applied to the high-strength reinforcing bar 11 by the prestress introduction nut 7, that is, a prestress (compressive stress) in the PC wall plate 1. Thereafter, the non-shrink mortar is filled as the filler 6 into the portion shown in FIGS. 1 to 3 and finished as a seismic reinforcement wall. The non-shrinking mortar 6 is filled with a reinforcing member 3 (PC wall plate 1 built in an existing RC frame at the construction site and pre-arranged and fixed to the upper and lower ends of the existing RC column 4 ( (Clad steel plate) and the steel frame 2 in the PC wall plate 1 are fastened by the joining bolt 8 and the nut 9 via the joining member 14 welded to the steel frame 2.
[0015]
Since the seismic reinforcement structure of the existing building of the present invention configured as described above introduces pre-stress to the PC wall plate 1, it is possible to increase the resistance to the shear crack of the seismic reinforcement wall, and in the unlikely event. Even when cracking occurs, the expansion of the seismic reinforcement wall can be suppressed to a small level, and damage to the existing RC frame due to the expansion of the seismic reinforcement wall can be prevented.
[0016]
The reinforcing member 3, in this embodiment, the coated steel plate is disposed and fixed to at least the upper and lower ends of the existing RC column 4. In this embodiment, as shown in FIG. 2, a steel plate is fitted in the cross-section of an existing RC column 4 in a U-shape and fixed through an adhesive 10 or filling mortar 10. By arranging and fixing the reinforcing member 3, the shear strength of the upper and lower ends of the RC column 4 is remarkably enhanced. As a reinforcing means for the upper and lower ends of the existing RC column 4, for example, a method of winding carbon fiber around the upper and lower ends of the RC column 4 can be adopted.
[0017]
In this way, in the present invention, the reinforcing members 3 (covered steel plates) are disposed and fixed on at least the upper and lower ends of the existing RC columns 4, so that the seismic reinforcing walls are diagonally formed by a horizontal force due to an earthquake or the like. Even when the shear force concentrates on the upper and lower ends of the existing RC column 4, the shear failure of this portion can be reliably prevented.
[0018]
Thus, since the existing RC frame does not break, the horizontal shear strength of the additional seismic reinforcement wall is determined by the shear strength of the PC wall plate 1, and if the strength of the PC wall plate 1 is increased, the additional seismic reinforcement structure The horizontal shear strength can also be increased. This means that the horizontal shear strength of the expanded seismic reinforcement structure can ultimately be increased up to the bending yield strength, and the seismic reinforcement structure is surely stronger than the conventional reinforcement structure.
[0019]
Reference numeral 5 denotes an RC beam, which is in an existing building, and together with the RC column 4 constitutes an RC frame.
[0020]
Next, the construction method of the seismic reinforcement structure of the existing building of this invention is demonstrated. First, the PC wall board 1 is prefabricated in a factory. In this embodiment, the wall bars 13 and the high-strength reinforcing bars 11 such as PC steel bars are arranged in a lattice shape so as to be parallel to the side of the PC wall plate 1 inside the steel frame 2 frame.
As shown in FIGS. 2 and 3, the wall bars 13 are arranged on the front and back layer sides in the thickness direction of the PC wall board 1 and the high-strength reinforcing bars 11 are arranged in the center. At that time, as shown in FIGS. 2 and 3, the end portion of the high-strength reinforcing bar 11 where the screw is engraved protrudes through a hole formed in the web portion of the steel frame 2 (H-shaped steel). Clamp and fasten with the prestress introduction nut 7.
In this state, the formwork is mounted, concrete is placed, and the PC wall board 1 is factory-produced (prefabricated).
[0021]
On the other hand, as shown in FIG. 2, reinforcing members 3 having a U-shaped cross section made of steel plates are fitted into the upper and lower ends of RC columns 4 of an existing building, and the adhesive 10 or the mortar 10 is interposed therebetween. Stick. Thus, the upper and lower ends of the existing RC column 4 are reinforced to increase the shear strength.
[0022]
Next, the prefabricated PC wall plate 1 is built in the RC frame composed of the existing RC columns 4 and beams 5, and the left and right screws are installed at the opposite ends of the PC wall plate 1 as shown in FIG. The engraved high-strength reinforcing bar 11 is protruded through a hole formed in the web part of the steel frame 2 (H-shaped steel) in the PC wall plate 1, and a coupler 12 (turn buckle) is screwed into this. Then, the PC wall plate 1 is fastened by the coupler 12, and a predetermined prestress is applied to the vertical and horizontal high-strength reinforcing bars 11 by the prestress introduction nut 7.
[0023]
After that, as shown in FIG. 2, the steel frame 2 in the PC wall plate 1 and the reinforcing members 3 (coated steel plates) disposed and fixed to at least the upper and lower ends of the existing RC columns 4 are as shown in FIG. It is fastened with a field joining bolt 8 and a nut 9 via a joining member 14 welded and fixed to the steel frame 2.
[0024]
Thereafter, as shown in FIG. 1 to FIG. 3, there is no shrinkage filling between the PC wall plate 1 and the existing RC columns 4 and beams 5 and between the steel frame frames 2 of the adjacent PC wall plates 1. Placing and curing mortar to complete the seismic reinforcement wall of the existing building. In addition, if the PC wall board 1 is an apertured wall panel, it is possible to provide an earthquake expansion reinforcement with an apertured additional wall.
[0025]
FIG. 4 schematically shows the load / deformation characteristics of the seismic reinforcement structure of the existing building of the present invention in comparison with that of the conventional seismic reinforcement structure.
In FIG. 4, a curve a is a load / deformation characteristic when an earthquake-proof reinforcement wall is not added in an existing building, and a curve b is a load / deformation characteristic of a case where an earthquake-proof reinforcement wall is added according to the prior art. The load / deformation characteristics when shear failure occurs at the joint between the expanded seismic reinforcement wall and the existing RC column and beam and at the upper and lower ends of the existing RC column are shown. Curve c shows the load / deformation characteristics when shear failure occurs in the additional seismic reinforcement wall when the upper and lower ends of the existing RC column are reinforced.
[0026]
The curve d reinforces the upper and lower ends of the existing RC column of the present invention, and connects the PC wall plate to the existing RC without connecting the additional seismic reinforcing wall and the existing RC frame with an anchor bolt or the like. Load and deformation of the seismic reinforcement structure built in the frame, fastening the reinforcing members at the upper and lower ends of the existing RC pillars and the steel frame members of the PC wall plate, and introducing prestress vertically and horizontally to the additional seismic reinforcement wall Show the characteristics. It shows that deformation progresses until the seismic reinforcement wall is destroyed by bending yielding.
[0027]
As is clear from FIG. 4, the seismic reinforcement structure for an existing building of the present invention has excellent load / deformation characteristics.
[0028]
【The invention's effect】
According to the present invention, there is no need to drill anchor bolts or the like in RC pillars or beams (RC frame) in an existing building, so the RC frame is not damaged and the strength is not lowered. In addition, since the existing RC pillars are reinforced with reinforcing members such as steel plates, it is possible to reliably prevent shear failure of this part, and to make an earthquake-proof reinforcement structure with high load / deformation characteristics. it can.
[0029]
Since the prestress is introduced into the expanded seismic reinforcement wall in the vertical and horizontal directions, even if horizontal shearing force due to earthquakes acts on the wall panel (PC wallboard), the existing RC structure is caused by the expansion of the wall panel. It is extremely rare to reduce the strength by damaging the pillars and beams (RC frame). In the unlikely event that a wall panel is cracked, the crack is not noticeable.
[0030]
Since the wall plate (wall panel) for expansion seismic reinforcement wall in the present invention can be produced (prefabricated) at the factory, it can be a high-quality high-strength concrete wall plate. The wall panels obtained in this way are built at the construction site, the wall panels are joined together with couplers, the steel frame on the wall panels is fastened to the upper and lower ends of the RC columns of the existing building, and the non-shrink mortar is attached. It can be implemented simply by filling. Thus, when the seismic reinforcement wall is added, noise, vibration and dust are not generated, and the construction is easy and can be performed in a short period of time.
[Brief description of the drawings]
FIG. 1 is a front view showing a seismic reinforcement structure of an existing building according to the present invention. FIG. 2 is a cross-sectional view showing a joining state of a reinforcing portion of an existing RC column in the present invention and a steel frame in a PC wall plate. [Fig. 3] Cross-sectional view showing the state of joining and fastening between PC wall plates [Fig. 4] Graph showing the load / deformation characteristics of the seismic reinforcement structure of an existing building according to the present invention in comparison with the conventional technology Explanation of]
1 PC wall plate 2 Steel frame 3 Reinforcing member (coated steel plate)
4 Existing RC columns 5 Existing RC beams 6 Filling material (non-shrink mortar)
7 Pre-stress introduction nut 8 On-site joint bolt 9 Nut 10 Adhesive or filling mortar 11 High strength rebar 12 Coupler 13 Wall rebar 14 Joint member

Claims (4)

At least the upper and lower ends of the RC columns (4) of the existing building are U-shaped in cross section, and have openings toward the PC wall plate (1) to be built in the RC frame, A reinforcing member (3) in which both wall portions forming the opening extend beyond the vertical wall surface of the RC column (4 ) is disposed and fixed, and at least above and below the RC column (4). The PC wall plate (1), in which the ends are reinforced and the concrete is placed by placing the wall reinforcement (13) and the prestress introduction reinforcement (11) inside the steel frame (2), is attached to the existing building. Reinforcing member (3) built in an RC frame composed of RC columns (4) and beams (5), and disposed and secured to at least the upper and lower ends of the RC columns (4) of the existing building a steel frame of the PC wall panel (1) and (2), steel frame (2), PC wallboard thickness (1) One end of the joint member toward each side (14) fixed, the extended portion of the abut vertically wall bolt (8) of the reinforcing member and the other end (3) and joined by fastening by a nut (9) Furthermore, the seismic reinforcement structure of the existing building which arrange | positions a filler (6) between the steel frame (2) of RC frame inner peripheral surface and PC wall board (1) at least.   The reinforcing member (3) disposed and fixed at least at the upper and lower ends of the RC column (4) of the existing building is a steel plate, for introducing wall reinforcement (13) and prestress in the PC wall plate (1) The reinforcing bars (11) are arranged in a grid pattern in the vertical and horizontal directions or in a grid pattern inclined with respect to the axis of the RC column (4) of the existing building, and the filler (6) The seismic reinforcement structure for an existing building according to claim 1, wherein is mortar. At least the upper and lower ends of the RC columns (4) of the existing building are U-shaped in cross section, and have openings toward the PC wall plate (1) to be built in the RC frame, A reinforcing member (3) in which both wall portions forming the opening extend beyond the vertical wall surface of the RC column (4 ) is disposed and fixed, and at least above and below the RC column (4). Reinforcing the ends, on the other hand, placing the wall reinforcement (13) and the prestress introduction reinforcement (11) in the steel frame (2) and placing concrete to prefabricate the PC wallboard (1) The PC wall plate (1) is built in an RC frame composed of RC columns (4) and beams (5) of an existing building, and at least upper and lower ends of the RC columns (4) of the existing building steel frame disposed-anchored reinforcing member (3) and PC wallboard (1) to (2) and a steel frame (2) One end of the joining member (14) is fixed to both sides of the PC wall plate (1) in the thickness direction, and the other end is abutted against the vertical wall surface of the extending portion of the reinforcing member (3), and the bolt (8) and Fastened with a nut (9) and joined, and prestress is introduced by applying tension to the prestress introducing rebar (11) in the PC wall plate (1), and at least the inner peripheral surface of the RC frame and the PC wall plate The construction method of the seismic reinforcement structure of the existing building characterized by arrange | positioning a filler (6) between the steel frame (2) of (1).   The reinforcing member (3) disposed and fixed at least at the upper and lower ends of the RC column (4) of the existing building is a steel plate, for introducing wall reinforcement (13) and prestress in the PC wall plate (1) The reinforcing bars (11) are arranged in a grid pattern in the vertical and horizontal directions or in a grid pattern inclined with respect to the axis of the RC column (4) of the existing building, and the filler (6) The construction method of the earthquake-proof reinforcement structure of the existing building of Claim 3 which is a non-shrink mortar.

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