JPH02132238A - Vibration proof structure made of rc - Google Patents

Abstract

PURPOSE:To enhance the vibration-proof ability by forming an arched frame member composed of vertical frames and a crosswise frame inside of an opening surrounded by columns and beams, and by providing an inverted V-like shape brace inside of the frame member. CONSTITUTION:An opening 3 is formed by columns 1 and beams 2 made of reinforced concrete. Further, an arched frame section is formed with the use of left and right vertical frames 5 and an upper crosswise frame 6 which are formed of H-shaped steel framework, and non-shrink mortar 9 is charged in a space between the vertical frame 5 and the column 1. The lower end parts of braces 7 are connected to the base end parts of the vertical frames 5 by means of gusset plates 10, and the upper parts of the braces 7 are connected to the center section of the crosswise frame 6, being spaced from each other.

Description

[Detailed Description of the Invention] <<Industrial Application Field>> The present invention relates to a steel-based seismic element that improves the seismic performance of openings in reinforced concrete structures, and in particular seismic reinforcement that is characteristic of seismic elements for openings in RC structures. Regarding structure.

<<Conventional Technology>> When constructing a building frame using reinforced concrete (RC), the cross-sectional area of columns and beams was increased in order to improve seismic performance.

Earthquake-resistant walls were also installed.

However, these methods reduce the floor space and require reinforcement to account for the increased weight. Therefore, a steel frame with braces is installed inside the opening in the RC structure to reduce the cross-sectional area of the columns and beams. There were also construction methods that made it possible to make the walls smaller and to omit earthquake-resistant walls.

<<Problem to be solved by the invention>> However, when a steel frame equipped with braces is applied to an existing RC structure, when the lower horizontal frame protrudes above the floor surface, it may cause problems such as doors for passing through. It is difficult to walk even if the RC frame is set, and if it were to be cut, the connection strength between the RC frame and the vertical frame and the existing horizontal frame would have to be reinforced, and the strength of the connection between the steel frame and the RC frame would have to be reinforced. In order to improve stress transmission, mortar or the like is filled between the two to form a close connection, which poses a burden in terms of quality control of the mortar and construction management.

For example, non-shrinking mortar is used, and this involves press-fitting.

The present invention has been made in view of the above circumstances, and its purpose is to provide a lightweight seismic reinforcement structure that can ensure an opening that is flat with the floor surface, and at the same time has good toughness.

<Means for Solving the Problems> In order to achieve the above object, the RC building seismic reinforcement structure according to the present invention is a structure in which an opening surrounded by reinforced concrete columns and beams is reinforced with braces. Attach the vertical frame, cross the upper horizontal frame at a position above the vertical frame and slightly lowered from the beam, and diagonally from the midway part of the upper horizontal frame to the bottom of each of the left and right vertical frames. Lowered left and right braces are provided, and the points where the left and right braces are connected to the upper horizontal frame are set at locations facing each other and slightly separated from each other, and the upper horizontal frame portion sandwiched between these connection points acts as a shearing panel. Let it happen.

《Function》 The vertical frame and the upper horizontal frame constitute a concave frame member, and the brace enters into it in the shape of a letter “C”, forming symmetrical triangles at both ends, and the brace and the upper horizontal frame form a symmetrical triangle. The connecting part is slightly separated on the upper horizontal frame and a part of the upper horizontal frame is sandwiched, so if an input that pushes the opening in one direction is applied, the opening by the pillars and beams will be It deforms into a parallelogram shape, but a tensile force acts on one brace, a compressive force acts on the other brace, and no moment is applied to the brace, and the horizontal part sandwiched between the brace connection parts of the upper horizontal frame Pull one end down and push the other end up. Since there is a gap between the beam and the upper horizontal frame, the axial force of the brace acts as a shearing force on the part of the upper horizontal frame sandwiched between the brace connections, and if a strong seismic force above a certain level is applied, the above Part of the upper horizontal frame collapses without damaging other members.

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

FIG. 1 shows how a reinforcing structure 4 is installed in an opening 3 of a reinforced concrete frame made up of columns 1-1 and beams 2-2.

This reinforcing structure 4 functions as a steel-based earthquake-resistant element, and in consideration of manufacturing cost and strength, an H-shaped steel frame is adopted, but it may also be constructed of other different types of metal. A gate-shaped frame 6 is provided, and a brace 7 is passed between the upper horizontal frame 6 and the vertical frame 5.

Then, 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 the vertical frame 5-
It passes horizontally between 5 and 5.

The vertical frame 5-5 can be welded to the anchor bolts driven into the opening 3 side of the column 1-1, or stud bolts can be driven in addition to the anchor bolts to the vertical frame 5-5 side, and the vertical frame 5 and column 1 can be connected together. The vertical frame 5-5 is fixed to the column 1-1 by filling the space between the columns with non-shrinkage mortar 9 so as to be in close contact with each other.

Of course, if the pillar 1-1 is not an existing one but a new one, the vertical frame 5-5 may be integrated when the fresh concrete is poured.

Next, the mounting position of the brace 7-7 is such that its lower part is connected to the base end of the vertical frame 5-5 with a gusset plate 10, and its upper part is connected to the center part of the upper horizontal frame 6 with a gap A between them. ing. Then, the web of the upper horizontal frame 6 related to the connection part between the upper horizontal frame 6 and the brace 7 is reinforced with a stiffener, and each of the upper and lower flanges is also attached with a cover plate 11 from the outer end of the brace 7 in the direction of the vertical frame 5. It is reinforced and reinforced.

Therefore, compared to the triangular portion formed by the vertical frame 5, the brace 7, and the upper horizontal frame 6, the central portion of the upper horizontal frame 6 (the portion with the interval A) is more likely to bend vertically.

That is, when a lateral load is applied to the opening 3, the reinforcing structure 4
Stresses such as axial force, bending moment, and shearing force act on each member, and when a certain proof stress is exceeded, the brace 7 and the upper horizontal frame 6
The central portion sandwiched between the connection points (the portion at interval A) yields due to shearing first. Therefore, this part is sheared panel 12
It can be made to act as In order to deform the shear panel 12 sufficiently, the gap 8 needs to be large enough to leave enough room for the deformation.

<<Effects>> As described above in detail, according to the seismic reinforcement structure of the present invention, the frame members are assembled in a gate shape, and the "V"-shaped brace is provided inside thereof, so that the lower part of the opening is It can be a continuous flat surface on the floor, and the height of the passage can be ensured even when the opening angle of the braces is selected to form a passage within the opening.

Furthermore, since there is no need to densely fill the space between the upper horizontal frame and the bottom of the beam with mortar, etc., there is no need for quality control of mortar or construction management, and the number of constituent members can be reduced.

Furthermore, since the middle part of the upper horizontal frame where the connection points with the braces face each other acts as a shear panel, it constitutes a reinforced structure with toughness, making it ideal for beam collapsing type buildings. In addition, since the shear panel has good energy absorption properties, the present invention has a function of concentrating and absorbing seismic energy in the shear panel, reducing the response displacement during an earthquake, and reducing earthquake damage to other parts. In other words, it has a vibration damping effect. The shear strength of the portion corresponding to the shear panel can be easily adjusted by adjusting the cross-sectional area of the upper horizontal frame and the inclination angle of the brace.

Furthermore, the toughness can be adjusted by adjusting the length of the shear panel.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an earthquake reinforcement structure according to the present invention. 1... Column 3... Opening 5... Vertical frame 7... Brace 9... Mortar 11... Cover plate

Claims (1)

[Claims] (1) In a structure in which an opening surrounded by reinforced concrete columns and beams is reinforced with braces, vertical frames are attached to the columns, and the upper and horizontal frames are placed above the vertical frames and slightly lowered and separated from the beams. A frame is installed across the frame, and left and right braces are provided diagonally downward from the middle part of the upper horizontal frame to the bottom of each of the left and right vertical frames, and the points where the left and right braces are connected to the upper horizontal frame are opposite to each other. This seismic reinforcement structure of RC building is characterized in that the upper horizontal frame part sandwiched between the connecting points is set at a part slightly separated from the connecting part and acts as a shearing panel.