JPH0751803B2 - Seismic retrofitting method for RC structure opening - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a seismic retrofitting method for improving seismic performance of an opening of a reinforced concrete structure.

<Prior art> When constructing a building from reinforced concrete, the cross-sectional area of columns and beams was increased in order to improve seismic performance. In addition, earthquake resistant walls were also installed.

<Problems to be solved by the invention> Increasing the cross-sectional area of columns and beams will reduce the living space and increase the weight. In addition, since the seismic wall does not have high toughness, the weight increases due to the need to increase the strength. Especially, we are paying attention to the reinforcement of the opening in the seismic wall, but a reinforcing method with high toughness is expected.

The opening was closed by the earthquake-resistant wall, and there was also a loss of usability because the opening disappeared. If you make an opening in the earthquake resistant wall,
This is because the reinforcement efficiency is reduced. The present invention has been made in view of the above circumstances, and an object thereof is to solve the above-mentioned conventional problems. That is, it is to improve the seismic performance of the opening of the existing reinforced concrete frame or the new reinforced concrete frame.

<< Means for Solving the Problem >> In order to achieve the above-mentioned object, the seismic reinforcement method of the RC structure opening portion according to the present invention is arranged along the inner peripheral surface of the reinforced concrete structure structure to be reinforced and inside the opening portion. A quadrangular frame that fits is formed, and a shear panel is provided by being hung from the upper side of the frame, and the shear panel serves as an apex, and the lower side of the frame forms a triangular shape with the bottom side of the frame. A metal-type seismic resistant structure is provided by providing a brace that diagonally rises from the lower side toward the shear panel to form the triangular hypotenuse, and an appropriate distance is provided between the outer peripheral surface of the frame and the inner peripheral surface of the opening. The metal-based seismic resistant structure is fixed in the opening by joining by means.

In addition, when newly forming a reinforced concrete structure and its opening, a rectangular frame is formed along the inner peripheral surface of the opening, and a shear panel is hung from the upper side of the frame, and the shear panel is provided. A metal brace is provided, which has a brace forming a triangular hypotenuse by obliquely rising from the lower side of the frame toward the shear panel so that the lower side of the frame forms a triangular shape having a bottom side. A seismic resistant structure is constructed, the metal-based seismic resistant structure is built in the opening forming position of the reinforced concrete structure, concrete is placed, and the frame is integrally closely fixed to the inner peripheral surface of the opening, It is characterized in that a system earthquake-resistant structure is constructed integrally with the opening.

<Operation> To explain the operation of the present invention, in any case of new installation and repair, when reinforcing the opening of the RC structure, the metal-based seismic resistant structure is installed in the opening. Therefore, as compared with the conventional method of increasing the cross-sectional area of the pillar or the beam, it is possible to secure a wider living space and the weight increase due to the increase of the cross-sectional area is eliminated. On the other hand, even if compared with the method that adopts the conventional earthquake-resistant wall,
In the reinforcing method of the present invention, since the opening is reinforced by the metal-based seismic resistant structure that is expected to have toughness, it is possible to make the weight lighter than the seismic resistant wall and ensure more effective seismic reinforcing. Further, regarding the formation of the opening which is concerned about in the earthquake-resistant wall, the metal-based earthquake-resistant structure adopted in the present invention is composed of the frame and the brace and the shear panel which are arranged in a triangular shape inside the frame. In the first place, there is a gap between them, so that a desired opening can be secured by utilizing this gap without diminishing the strength of the earthquake-resistant structure.

Furthermore, explaining the function of the metal-based seismic resistant structure adopted in the present invention, with the brace forming the hypotenuse of the triangle, and the shear panel provided between the upper side of the frame at the apex of the triangle,
A Y-shaped toughness-resistant brace structure is formed in a rectangular frame. With respect to external force such as seismic force acting on the opening, the rectangular frame disperses the stress, thereby preventing damage to the RC skeleton and the joint between the RC skeleton and the frame. In addition, the brace converts the same external force such as seismic force acting on the opening into tensile force and compression force,
You can resist this. In addition, the shear panel
It is interposed between the frame and the brace to absorb the energy transmitted between them and cooperate with the frame to resist the moment and shearing force generated around the shear panel. Therefore, even if a deforming force acts on the opening due to an external force such as seismic force, the RC structure can be effectively seismically reinforced by the metal-based seismic structure composed of these frames, braces and shear panels.

<Example> Hereinafter, a preferred example of the present invention will be described in detail with reference to the drawings.

Fig. 1 shows the case where a steel frame seismic resistant structure 4 is applied to a rectangular opening 3 surrounded by columns 1 and beams 2 of reinforced concrete structure (RC structure). In this embodiment, basically, along the inner peripheral surface of the opening 3 to be reinforced, which is surrounded by the RC-made columns 1 and beams 2,
A quadrangular frame 5 that fits in the opening 3 is configured, and a shear panel 7 is provided by hanging it from the upper side of the frame 5, and the shear panel 7 serves as an apex, and the lower side of the frame 5 has a triangular shape with the bottom side. As described above, the braces 8 that obliquely stand up from the lower side of the frame 5 toward the shear panel 7 to form the triangular hypotenuses are provided to configure the steel-based seismic resistant structure 4, and the outer peripheral surface of the frame 5 and the opening. The steel-frame-based seismic resistant structure 4 is fixed in the opening 3 by joining the inner peripheral surface of the structure 3 with an appropriate means.

That is, the frame 5 is formed by assembling the H-shaped steel into a similar shape smaller than the opening 3. Then, the central partial web of the upper horizontal frame located on the upper side of the frame 5 and both end partial webs of the lower horizontal frame located on the lower side are reinforced by the stiffeners 6. Further, the shear panel 7 is suspended and fixed to the central portion of the upper horizontal frame of the frame 5, and the braces 8 that are raised obliquely upward from both ends of the lower horizontal frame are connected and fixed to the suspended lower end of the shear panel 7. .

The steel-frame-based seismic resistant structure 4 having the above-described configuration does not directly connect the brace 8 in the frame 5 in the “C” shape, but is in the “Y” shape via the bundle-shaped shear panel 7. The toughness is enhanced by the elasticity of. When attaching the steel frame type seismic resistant structure 4 to the opening 3, after mounting the anchors 9 on the columns 1 and the beams 2 and attaching the studs 10 on the outer peripheral surface of the frame 5 as shown in FIG. Then, the non-shrinkable mortar 11 is placed between the anchor 9 and the stud 10 in the opening 3 to complete the mounting and fixing.

In addition, as shown in FIG. 3, the structure of the brace 8 of the steel frame type seismic resistant structure 4 is such that two shear panels 7a-7a are arranged side by side in the frame 5a so as to be separated from each other, and the brace 8a is formed from each shear panel 7a-7a. It is also possible to lower it diagonally. That is, the braces 8a assembled in a Y shape are arranged side by side in the frame 5a formed in a quadrangle.

By doing so, the positions of the shear panels 7a-7a are shifted toward both ends, and the position, height and width of the window opening 12 provided when the braces 8a, 8a are stretched in the opening 3 can be changed.

FIG. 4 and subsequent figures show another embodiment. This is a case where a RC structure is newly built together with the pillar 1 and the beam 2, and the steel frame seismic resistant structure 4 is integrated into the RC structure when placing concrete. In this embodiment, basically, RC-made columns 1 and beams 2,
In addition, when the opening portion 3 is newly formed, a rectangular frame 5 is formed along the inner peripheral surface of the opening portion 3, and the shear panel 7 is provided so as to hang down from the upper side of the frame 5 and the shear panel 7
And the lower side of the frame 5 has a triangular shape with the bottom side being the bottom side. The brace 8 is diagonally raised from the lower side of the frame 5 toward the shear panel 7 to form the oblique side of the triangular shape.
To construct a steel-based seismic-resistant structure 4, build the steel-based seismic-resistant structure 4 at the opening 3 forming position of the RC structure, and pour concrete into it, and the frame 5 is integrated with the inner peripheral surface of the opening 3. The steel frame type earthquake-resistant structure 4 is constructed integrally with the opening 3.

That is, as shown in FIG. 5, studs 10 are struck on the outer peripheral surface side of the frame 5, and concrete for the pillar 1 (beam 2 is the same) is struck.
Therefore, the frame 5 and the pillar 1 and the beam 2 are solidly integrated.

In the present embodiment described above, the brace 8 and the shear panel 7 constitute a Y-shaped toughness resistant brace in the rectangular frame 5.
The frame 5 measures the dispersion of stress generated by an external force such as seismic force acting on the opening 3 to prevent damage to the RC frame and the joint between the frame 5 and the RC frame. By sufficiently increasing the strength and rigidity of the brace 8 here, damage is concentrated on the shear panel 7 when an excessive seismic force is applied. In other words, the shear panel 7 can be appropriately set with appropriate strength and large toughness such that the shear panel 7 buckles prior to the frame 5 and the brace 8. Therefore, the shear panel 7 absorbs a large amount of energy in the event of an earthquake, and thus the shear panel 7 has a large amount of energy. It functions as a damper that reduces the response deformation and reduces damage to the building, and exerts a vibration damping effect.

Furthermore, the shear panel 7 can cooperate with the frame 5 to resist the moment and shear force generated around the shear panel 7.

Further, the bottom portion of the frame 5 to which the lower end portion of the brace 8 is connected resists the tensile force and the compressive force together with the brace 8.

In this way, the steel frame seismic resistant structure 4 including the frame 5 and the Y-shaped brace including the shear panel 7 and the brace 8 can resist the deformation force of the opening 3.

Further, since the seismic resistant structure 4 is composed of a metal-based steel frame or the like having a higher strength than reinforced concrete, it is lighter than a reinforced concrete earthquake resistant wall, and is advantageous in that the weight of the building is not increased. Due to this, it is generally difficult to reinforce the building foundation, but there is no need for the foundation reinforcement work accompanying this seismic reinforcement. Further, if the above-mentioned foundation reinforcement is performed, the weight of the building will increase accordingly, and the seismic input will increase in proportion to this building weight. The seismic input is almost unchanged, and the reinforcement efficiency is higher than other conventional reinforcement methods in which the building weight increases.

Similarly, in terms of reinforcement efficiency, in the reinforcement method of adding a reinforced concrete earthquake-resistant wall, the seismic performance deteriorated when windows and doors were installed, but in this example, the seismic performance was not diminished and the opening Can be set.

Further, while supporting the inner peripheral surface of the opening 3 by the rectangular metal frame 5, the shearing panel 7 and the brace 8 prevent deformation stress.
It can be distributed and transmitted to the frame 5. Further, by setting the shear panel 7 to yield before the RC structure above a certain level of seismic force, it is possible to prevent buckling or yielding of the brace 8. Therefore, the toughness of the present embodiment is better than that of the conventional strength / resistance type brace, so that the strength of the frame 5 may be set small in order to obtain the same seismic resistance. Therefore, the member cross section can be reduced,
It is economical, the increase in weight can be suppressed, and the reinforcing efficiency is improved. Furthermore, since the stress at the joint with the reinforced concrete frame is also small, the strength of the joint can be set to be small, and the amount of anchoring materials such as anchors 9 and studs 10 required for joining with the existing concrete frame can be reduced. Can be done, construction becomes easy,
It is possible to reduce the construction period and the construction cost.

Further, even when the reinforcing structure is previously incorporated in the new RC structure, it is sufficient to provide the normal stud 10 on the frame 5 side, and the same effect can be obtained.

Furthermore, since appropriate strength and large toughness can be separately set in the shear panel 7, it is possible to exert a large energy absorption capacity during an earthquake. By concentrating the damage on the shear panel 7, most of the seismic energy applied to the entire building can be absorbed by the shear panel 7, and as a result, the response deformation of the building is reduced and damage is reduced. Also, it is possible to have a damping effect that functions as a damper, and it is easy to repair the RC structure after an earthquake. That is, since replacement of the shear panel 7 is sufficient, there is an effect that the repair becomes easy.

Furthermore, only when a large earthquake is predicted, the metal-based seismic resistant structure 4 as in this embodiment can be attached to the RC structure opening 3 and can be used as an open space normally.

Further, since the frame 5 can be easily removed by removing the joint between the frame 5 and the opening 3, it is easy to replace it with another seismic structure having a different inclination angle of the brace 8 and a mounting position of the shear panel 7. In addition, the position and size of the window opening can be changed.

If the toughness of the RC structure is good, the behavior of the metal-based seismic resistant structure 4 is not wasted, which is particularly effective.

The seismic resistant structure 4 of this embodiment including the frame 5 and the Y-shaped brace
When the RC structure is to be integrally mounted when concrete is poured, the seismic resistant structure 4 and the RC structure can be closely connected and integrated, so that mutual force transmission is good and a special connection integration No work is required, good toughness can be secured, and seismic force can be effectively absorbed. Therefore, it is possible to make the cross-sectional area of the RC structure considerably smaller.

As described above, according to the construction method of this embodiment, since the reinforcing efficiency is high, the construction site to be reinforced can be minimized. That is, not only the construction period and construction cost can be reduced, but also when constructing a building that is in use, it is possible to flexibly deal with the situation, and especially construction of a building such as a hospital or inn where the use of the building cannot be interrupted. Is advantageous to

In addition, it can be similarly incorporated into a steel-framed reinforced concrete building as a seismic element, and can be applied to civil engineering structures such as railway bridges and road bridges.

<< Effects >> In short, according to the present invention, in the case of new installation, in any case of repair, when reinforcing the opening of the RC structure,
Since the metal-based seismic resistant structure is installed inside the opening, it is possible to secure a wider living space and to cut the area compared to the conventional method of increasing the cross-sectional area of columns and beams. There is also no increase in weight due to the increase in area.
On the other hand, even when compared with the conventional method of adopting a seismic wall, the reinforcing method of the present invention is reinforced with a metal-based seismic structure that can be expected to have toughness, so it is lighter than a seismic wall and more effective. Seismic reinforcement can be secured. further,
As for the formation of an opening that may be a concern in the earthquake-resistant wall, the metal-based earthquake-resistant structure adopted in the present invention is composed of the frame and the brace and the shear panel arranged in a triangular shape inside the frame. Since there is a gap between them in the first place, it is possible to secure a desired opening by utilizing this gap without diminishing the strength of the earthquake-resistant structure.

Further, in the metal-based seismic resistant structure adopted in the present invention, a brace forming the hypotenuse of a triangle and a shear panel provided between the top of the frame at the apex of the triangle form a rectangular frame. , Y-type toughness-resistant brace structure is configured, so the square frame disperses stress against external force such as seismic force acting on the opening, which allows RC frame and this RC frame to be dispersed. It is possible to prevent damage to the joint between the frame and the frame, and the brace can convert external force such as seismic force acting on the opening into tensile force or compressive force and resist it. Further, the shear panel is interposed between the frame and the brace, absorbs energy transmitted between them, and cooperates with the frame to resist moment and shear force generated around the shear panel. it can. Therefore, even if a deforming force acts on the opening due to an external force such as seismic force, the RC structure can be effectively seismically reinforced by the metal-based seismic structure composed of these frames, braces and shear panels.

[Brief description of drawings]

FIG. 1 is a front view showing an example of an RC steel-frame-based earthquake-resistant structure according to the present invention, FIG. 2 is a cross-sectional view showing a mounting state of the steel-frame-based earthquake-resistant structure, and FIG. 3 shows another aspect of the steel-frame-based earthquake-resistant structure. A front view, FIG. 4 is a front view according to another embodiment, and FIG. 5 is a cross-sectional view showing its mounting state. 1 ... Pillar, 2 ... Beam 3 ... Aperture, 4 ... Steel frame seismic structure 5 ... Frame, 6 ... Stiffener 7 ... Shear panel, 8 ... Brace 9 ... Anchor, 10 ... Stud 11 …… Mortar, 12 …… Window opening

Claims (2)

[Claims] 1. A quadrangular frame is formed along the inner peripheral surface of an opening to be reinforced of a reinforced concrete structure so as to fit within the opening, and a shear panel is provided so as to hang down from the upper side of the frame and the shear panel. And a bottom side of the frame to form a triangle shape having a bottom side, the brace forming the oblique side of the triangle is provided by obliquely rising from the bottom side of the frame toward the shear panel, A RC structure characterized in that the metal-based seismic resistant structure is fixed in the opening by joining the outer peripheral surface of the frame and the inner peripheral surface of the opening by an appropriate means. Seismic retrofitting method for building openings. 2. When newly forming a reinforced concrete structure and its opening, a rectangular frame is formed along the inner peripheral surface of the opening, and a shear panel is provided so as to hang down from the upper side of the frame. Providing a brace that diagonally rises from the lower side of the frame toward the shear panel so as to form a triangular shape with the shear panel as the apex and the bottom side of the frame as the bottom side. , Constructing a metal-based seismic resistant structure, placing the metal-based seismic resistant structure at the opening forming position of the reinforced concrete structure, placing concrete, and fixing the frame integrally and closely to the inner peripheral surface of the opening. , The metal-based seismic resistant structure is integrally constructed with the opening
Seismic retrofitting method for RC building openings.