JPH0751804B2 - RC structure seismic reinforcement structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a steel-based seismic element for improving seismic resistance of an opening of a reinforced concrete structure, and in particular, an earthquake-resistant element having a characteristic of an RC frame opening. Reinforcement structure.

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

However, these measures not only reduce the floor area but also require reinforcement to increase the weight.Therefore, a steel frame with braces is installed in the RC structure opening, and the cross-sectional area of columns and beams is increased. There was also a construction method that made it possible to reduce the size and eliminate the earthquake-resistant wall.

<< Problems to be solved by the invention >> However, a square steel frame with braces is
When applied to the opening of the RC structure, the lower lower horizontal frame projects above the floor surface, and even if a door intended to pass through is set, the height of the door cannot be secured high and it protrudes. The lower horizontal frame is an obstacle to walking. If the lower horizontal frame is cut in order to solve this, the connection strength between the RC structure and the vertical and horizontal frames must be strengthened. Also with a steel frame
In order to improve the stress transmission between the RC structure and mortar, etc., are filled between them in order to make a tight connection, especially for the work under the beam, in terms of quality control and work control of the mortar, etc. It was a burden. For example, as mortar, non-shrink mortar is used, and the work of press-fitting this under the beam is involved, but this work was complicated.

The present invention has been made in view of the above circumstances, and its purpose is to make it possible to secure a floor surface and a flat and relatively high opening, and at the same time have good workability and RC construction with good toughness. To provide the seismic reinforcement structure.

<< Means for Solving the Problem >> In order to achieve the above-mentioned object, the seismic reinforcement structure of the RC structure according to the present invention has a structure in which the openings surrounded by the columns and beams of the reinforced concrete structure are reinforced by braces, and A pair of vertical frames is attached to each of the vertical frames, and a gate frame is formed from the upper horizontal frame that is arranged below the beam with a gap and both ends thereof are connected to the vertical frames. One end of each of them is connected to the upper horizontal frame at a distance from each other with the central portion of the upper horizontal frame interposed therebetween, and the other end is connected to the vertical frame. A pair of braces are arranged obliquely toward each of the vertical frames, and a reinforcing member is arranged on the upper horizontal frame on the vertical frame side that is close to each of the connection parts with the braces. .

<< Operation >> To explain the operation of the present invention, since the frame body provided with the brace for reinforcing the opening is a gate type, there is no lower horizontal frame as in the conventional case, which is flat with the floor surface and relatively A high opening can be secured. Further, from the viewpoint of ensuring the reinforcement function described later, since a gap is set between the under beam and the upper horizontal frame of the gate frame, a mortar for closely joining the beam and the frame is provided. The filling work such as is unnecessary and the workability can be improved.

Explaining the function of the seismic strengthening structure consisting of the gate-shaped frame body and the brace and the like which constitute the present invention, a gate-shaped frame body is formed by a pair of vertical frames and upper horizontal frames, and the inside of this frame body is described. By arranging a pair of braces in the shape of "C" on each side, triangular portions are formed on both sides of the frame, and the brace and the upper horizontal frame are connected to each other at the central portion of the upper horizontal frame. The upper horizontal frame is connected to the upper frame with a reinforcing member on the side of the vertical frame that is close to each of the connections with the brace, so input that pushes the opening sideways can be performed. When the openings by the pillars / beams are deformed into parallelogram shapes by acting, a moment is not generated in the brace, a tensile force acts on one brace, and a compressive force acts on the other brace.
As a result, a shearing force that pulls one connecting portion downward and pushes the other connecting portion upward is generated in the central portion of the upper horizontal frame sandwiched by the connecting portions of the braces. Since a gap is set between the beam and the upper horizontal frame, the central part of the upper horizontal frame sandwiched by the brace connection parts reinforced by the reinforcing member will concentrate shearing on this. The central portion is buckled and collapsed prior to other peripheral members, and damage to other members can be prevented. That is, since the central portion of the upper horizontal frame is provided with the functionality as a so-called shear panel, this central portion exerts good energy absorption performance, and the shear panel portion in the central portion of the upper horizontal frame is subjected to an earthquake. It is possible to exert a function of concentrating and absorbing the energy, reducing the response displacement of the building at the time of an earthquake, and reducing the earthquake damage of other parts, that is, a damping effect. In this way, since the central portion of the upper horizontal frame sandwiched between the connecting portions of the braces functions as a shear panel, a reinforcing structure having toughness can be configured, which is optimal for a beam collapse type building.

<Example> Hereinafter, a preferred example of the present invention will be described in detail with reference to the drawings. This embodiment basically has a structure in which an opening 3 surrounded by a reinforced concrete pillar 1 and a beam 2 is reinforced with a brace 7, and a pair of vertical frames 5 attached to the pillar 1 and a gap below the beam 2 are provided. A gate form body 40 is formed from an upper horizontal frame 6 which is arranged at intervals of 8 and whose both ends are connected to each vertical frame 5, and one end of the gate form body 40 is placed on the upper horizontal frame 6 of the gate form frame 40. The center frame A of the horizontal frame 6 is sandwiched between them, and they are connected to each other with a space therebetween, and the other end is connected to the vertical frame 5.
A pair of braces 7 are arranged diagonally from the respective vertical frames 5 to the upper horizontal frame 6 and the vertical frame 5 side which is close to each connecting portion with the brace 7, and the stiffener, the cover plate 11, etc. It is configured by disposing a reinforcing member.

FIG. 1 shows a state in which a reinforcing structure 4 is incorporated in an opening 3 of a reinforced concrete frame composed of a column 1-1 and a beam 2-2.

This reinforcing structure 4 works as a steel frame seismic element, and adopts H-shaped steel bone in consideration of manufacturing cost and strength, but it may be composed of other kinds of metals, such as the left and right vertical frames 5 and upper and horizontal frames. The frame 6 constitutes a gate-shaped frame 40, and the brace 7 is provided between the upper horizontal frame 6 and the vertical frame 5.

The upper horizontal frame 6 is slightly lowered from the lower end surface of the upper beam 2, leaving a gap 8 between the beam 2 and the upper surface of the upper horizontal frame 6 and passing horizontally between the vertical frames 5-5.

Each of the vertical frames 5-5 is welded to an anchor bolt struck on the opening 3 side of the pillar 1-1, or a stud bolt is struck on the vertical frame 5-5 side in addition to the anchor bolts to fix the vertical frame 5 and the pillar 1 respectively.
The non-shrinkable mortar 9 is filled between the column and, and the vertical frame 5-5 is fixed to the column 1-1 so as to be in close contact with each other.

However, if the column 1-1 is not an existing one but is newly installed, the vertical frame 5-5 may be integrated when pouring the ready-mixed concrete.

Next, regarding the mounting position of the brace 7-7, the lower part is connected to the base end of the vertical frame 5-5 by the gusset plate 10, and the upper part is connected to the central part of the upper horizontal frame 6 with a space A therebetween. ing. Then, the web of the upper horizontal frame 6 related to the connecting portion between the upper horizontal frame 6 and the brace 7 is reinforced by stiffeners, and the upper and lower flanges of the upper plate 6 are also covered with the cover plate 11 in the direction of the vertical frame 5 from the outer end of the brace 7. Is applied to reinforce.

Therefore, as compared with the triangular portion formed by the vertical frame 5, the brace 7, and the upper horizontal frame 6, the central portion (the portion at the interval A) of the upper horizontal frame 6 is easily bent up and down.

That is, when a lateral load acts on the opening 3, the reinforcing structure 4
A stress such as an axial force, a bending moment, a shearing force, etc. acts on each member of, and when a certain proof stress is exceeded, the brace 7 and the upper horizontal frame 6
The central portion (the portion at the interval A) sandwiched between the connection points with and first shears and yields. Therefore, this part can act as shear panel 12. In order to sufficiently deform the shear panel 12, it is necessary that the gap 8 has a margin for deformation.

In this embodiment, the frame 40 is assembled in a gate shape, and the "H" -shaped brace 7 is provided inside the frame 40. Therefore, the lower portion of the opening 3 should be a flat surface continuous with the floor. Also, when forming a passage in the opening 3, the opening angle of the brace 7 can be selected to secure the height of the passage.

Further, since it is not necessary to densely fill mortar between the upper horizontal frame 6 and the lower part of the beam 2, neither quality control of mortar nor construction management thereof is required, and the number of constituent members can be small. Play.

Further, in the upper horizontal frame 6, the central portion 12 between the connecting portions with the brace 7 acts as a shear panel, so that a reinforcing structure having toughness can be configured, which is optimal for a beam collapse type building.
Further, since the shear panel 12 exhibits good energy absorption performance, the shear panel 12 concentrates and absorbs seismic energy, reduces response displacement of the building during an earthquake, and reduces earthquake damage to other parts. It exerts a function, that is, a damping effect. The portion A corresponding to the shear panel 12 can easily adjust the shear strength by adjusting the cross-sectional area of the upper horizontal frame 6 and the inclination angle of the brace 7.

Further, by adjusting the length of the shear panel 12, it is possible to adjust the toughness.

<< Effect >> In summary, according to the present invention, since the frame body provided with the brace that reinforces the opening is a gate type, there is no lower horizontal frame as in the conventional case, which is flat with the floor surface and relatively A high opening can be secured. Further, from the viewpoint of ensuring the reinforcing function, a gap is set between the beam bottom and the upper horizontal frame of the gate form body, so that mortar or the like for closely joining the beam and the frame body is used. The filling work is unnecessary and the workability can be improved.

Further, in the present invention, the brace and the upper horizontal frame are connected to each other at a distance from each other with the central portion of the upper horizontal frame sandwiched therebetween, and the vertical frame side close to the upper horizontal frame from each of the connection parts with the brace. Since a reinforcing member was arranged and a gap was set between the beam and the upper horizontal frame, the central portion of the upper horizontal frame sandwiched by the brace connection parts reinforced by the reinforcing member concentrates on this. As a result, shear deformation occurs, and the central portion is buckled and collapsed prior to other peripheral members, and damage to other members can be prevented. That is, since the central portion of the upper horizontal frame is provided with the functionality as a so-called shear panel, this central portion exerts good energy absorption performance, and the shear panel portion in the central portion of the upper horizontal frame is subjected to an earthquake. It is possible to exert a function of concentrating and absorbing the energy, reducing the response displacement of the building at the time of an earthquake, and reducing the earthquake damage of other parts, that is, a damping effect. In this way, since the central portion of the upper horizontal frame sandwiched by the connecting portions of the braces functions as a shear panel, a reinforcing structure having toughness can be configured.

[Brief description of drawings]

FIG. 1 is a front view showing a seismic strengthening structure of RC structure according to the present invention. 1 ... Pillar, 2 ... Beam 3 ... Opening, 4 ... Reinforcement structure 5 ... Vertical frame, 6 ... Upper horizontal frame 7 ... Brace, 8 ... Gap 9 ... Mortar, 10 ... Gusset Plate 11 …… Cover plate, 12 …… Shear panel 40 …… Gate formwork

Claims (1)

[Claims] 1. A structure in which an opening surrounded by a column and a beam made of reinforced concrete is reinforced by braces, and a pair of vertical frames attached to the column, respectively, and both end portions of which are arranged under the beam with a gap therebetween. Form a gate form body from an upper horizontal frame connected to each vertical frame, and one end of the gate form body is formed in the upper horizontal frame of the gate form body with a center portion of the upper horizontal frame interposed therebetween. And connecting the other end to the vertical frame, and disposing a pair of braces diagonally from the upper horizontal frame of the gate type frame body to each of the vertical frames, and in the upper horizontal frame, A seismic retrofit structure made of RC, characterized in that a reinforcing member is arranged on the side of the vertical frame that is close to each connection with the brace.