JPH1162308A - Damping structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an earthquake-proof ability by making a notch on a part of the earthquake-proof wall of a steel reinforced concrete, and giving a damping ability by means of a shearing transmittance mechanism of wall reinforcement generated by shearing deformation. SOLUTION: Vertical slits 3 are respectively formed near the posts at the left and right ends of an earthquake-proof wall 1, and a horizontal notch 4 is made at the nearly central part of height. The notched part 4 is needed to be plastically deformed by bearing force in order to operate as an energy absorption part at a great earthquake, as a result, a plastic deformation ability is raised by the use of the shearing transmittance of a wall reinforcement 5 by the stress of bearing strength. In the case where the reinforcement is not closely densed, or the strength is so small that bearing strength breakage takes place before the shearing breakage of concrete, such bearing strength breakage becomes dominant. In many existing buildings having a small concrete strength, repair work can be done for the earthquake proof wall by providing the slit 3 and notch 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic control structure for an earthquake-resistant reinforcement of an existing building and a new building or the like when it is necessary to reduce the seismic force of the building.

[0002]

2. Description of the Related Art Generally, earthquake-resistant walls of buildings are designed to have sufficient strength to withstand large earthquakes, and reinforcing bars are arranged to improve shear strength. Buildings with small seismic margins have been reinforced to increase the strength by adding walls.

[0003]

However, in the case of a middle-to-high-rise building, as the rigid walls are increased, the natural period becomes shorter and the seismic force acting due to the effect of the shorter period generally increases. . Further, the addition of the wall and the overstretching to increase the thickness are linked to the interruption or reduction of the architectural space, thereby impairing the functionality.

[0004] The present invention has been made in view of the above-mentioned conventional situation, and has as its object to provide a vibration control structure capable of improving the seismic performance without increasing the wall thickness or increasing the thickness.

[0005]

As a means for achieving the above-mentioned object, the present invention utilizes a shear transmission mechanism of a wall reinforcement generated by shear deformation by providing a cut in a part of an earthquake-resistant wall of a reinforced concrete structure. The gist is a vibration control structure that provides damping performance. In addition, horizontal cuts were made at approximately the center of the height of the shear wall as positions where shear deformation occurs, and horizontal cuts were made at the upper and lower ends of the shear wall as positions where shear deformation occurs. That is the gist.

[0006]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In FIG. 1, reference numeral 1 denotes an earthquake-resistant wall, which is provided with vertical slits 3 near pillars 2 at the left and right ends, and a horizontal notch 4 at a substantially central portion of the height. The notch 4 does not need to be a slit and may have a width of about several mm, but the depth is set under such a condition that this portion surely generates “shear deformation” during a large earthquake.

The notch 4 serves as an energy absorbing portion in the event of a large earthquake. In order to realize the energy absorption, it is necessary to carry out plastic deformation while maintaining proof stress. Utilizes shear transmission to improve plastic deformation capacity. If a part of the building has an energy absorbing part that has a plastic history, the seismic force acting on the building will be reduced due to the damping effect.

[0008] Destruction of a shear plane in which a reinforcing bar is present occurs when concrete under the reinforcing bar breaks down or shears. Stress level p _t of the reinforcing bar in shear plane
sigma _s is in the range of 40~80kgf / cm ^2, a shear force is transmitted by Bearing stress due concrete under rebar. That is, when the reinforcement is not very dense, or when the concrete has a small strength to bear and break before shearing, the bearing failure becomes dominant. The bearing stress is a local stress, and is a value that reaches about six times the uniaxial strength of concrete.

On the bearing stress transmitting surface, shear transmission is performed on the assumption that the reinforcing bar has reached the total plastic moment, and the hysteresis characteristics of the reinforcing bar are exhibited as characteristics of the stress transmitting surface. Bi-Linear with stable shear and shear deformation
Perform the elasto-plastic history of the mold. FIG. 3 shows the relationship between the shearing force and the displacement at the bearing surface.

Further, the proof stress of the shearing transmission surface where the bearing rupture is dominant can be expressed by the following equation.

(Equation 1)

In many existing buildings having a small number of wall streaks 5 and small concrete strength, many earthquake-resistant walls satisfying the conditions of bearing failure are provided, and slits 3 and cuts 4 are provided as shown in FIG. By performing renovation work, a seismic structure capable of absorbing energy can be obtained.

The repair work of the earthquake-resistant wall is not limited to the one shown in FIG.
For example, as shown in FIG.
In this case, a horizontal cutout 14 may be provided, or a horizontal cutout 24 may be provided between the earthquake-resistant wall 21 and the lower beam 26 as shown in FIG. In any case, by causing the cuts 14 and 24 to be displaced and deformed during the earthquake, the cuts can be used as bearing surfaces. In these cases, vertical slits 13 and 23 are provided near the columns 12 and 22 at the left and right ends of the earthquake-resistant walls 11 and 21, respectively.

By performing such renovation work, the strength of the building is reduced by an amount corresponding to the strength of the renovated earthquake-resistant wall. The received seismic force is reduced.

As shown in FIG. 4, assuming that the restoring force of the building excluding the repaired shear wall is (a) and the restoring force of the repaired shear wall is (b), the restoring force of the entire building is (a) and (a). b) is synthesized, and if the seismic force exceeds the strength of the renovated shear wall, the black-painted part absorbs energy due to the bearing failure of the renovated shear wall, and the seismic force acting on the building It functions as a vibration control structure that reduces noise.

In this case, the vibration damping effect is governed by the rigidity ratio and the proof stress ratio of (a) and (b) shown in the graph of the restoring force characteristic. It is also possible to adjust the stiffness ratio and the proof stress ratio by cutting the streaks, so that the vibration control effect can be optimally adjusted.

The bearing mode is not limited to the case where the shear-resistant wall undergoes shear deformation. Even when the middle and high-rise building is subjected to bending or shearing deformation, the bearing strength of the compression-receiving side wall is also considered. The destruction function is realized by exhibiting a restraining effect that increases.

[0017]

As described above, according to the present invention, a cut is made at the substantially central part of the existing earthquake-resistant wall or at the upper and lower beams.
By modifying so that the shear deformation occurs during a large earthquake, the hysteretic energy absorbing effect is exerted and the effect of reducing the seismic force is exhibited. Further, according to the present invention, it is possible to provide a vibration control structure which does not require any special vibration control device, and therefore does not depend on the dynamic characteristics of the device or the periodic characteristics of seismic waves. It has excellent effects such as not requiring maintenance work.

[Brief description of the drawings]

FIG. 1 shows an example of a vibration control structure according to the present invention.
(A) is a front view of a main part, and (B) is a cross-sectional view.

FIGS. 2 (a) and 2 (b) are front views each showing another example of the vibration control structure according to the present invention.

FIG. 3 is a diagram illustrating a relationship between a shearing force and a displacement on a bearing-breaking surface.

FIG. 4 is a relationship diagram between seismic force and horizontal deformation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Shear wall 2 ... Column 3 ... Slit 4 ... Cut 5 ... Wall striation 11, 21 ... Shear wall 12, 22 ... Column 13, 23 ... Slit 14, 24 ... Cut 16, 26 ... Beam

Claims (3)

[Claims] 1. A vibration control structure characterized in that a notch is provided in a part of an earthquake-resistant wall of a reinforced concrete structure, and a damping performance is imparted by utilizing a shear transmission mechanism of a wall reinforcement generated by shear deformation. 2. The vibration damping structure according to claim 1, wherein a horizontal cut is made in a substantially central portion of the height of the shear wall as a position where the shear deformation occurs. 3. The vibration control structure according to claim 1, wherein horizontal cuts are made at upper and lower ends of the earthquake-resistant wall as positions where the shear deformation occurs.