JPH01187272A - Continuous shear aseismic wall - Google Patents

Abstract

PURPOSE:To improve an aseismic performance of wall, saving steel materials to be used, by a method in which the lowest floor part is divided into left and right-handed sections at the center, column forms are attached to both sides of each divided earthquake-resistant wall, and the legs are fixed to an extent that inverse shearing forces do not occur. CONSTITUTION:In a reinforced concrete tall structure of ten or more floors, the lowest floor portion is divided into two left and right-handed sections at the center, and column forms 2 are attached to both sides of each divided aseismic wall A. The fixing degree of leg is made smaller to an extent that inverse shearing forces as responding shearing forces during earthquake do not occur. The construction work can thus be made easier by saving steel materials to be used and the increase in the loading shearing force of other vertical parts can be suppressed by avoiding the occurrence of inverse shearing forces.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a continuous shear wall in a high-rise reinforced concrete IJ-structure of about 10 stories or more.

(Prior Art) As reinforced concrete structures become taller, ensuring their seismic safety has become an urgent need. The majority of high-rise reinforced concrete buildings currently being constructed are of the so-called pure rigid-frame structure, which reduces the shaking of the building against wind loads, small to medium earthquakes, etc. (and prevents floors from falling due to layer collapse in the event of a major earthquake). It is desirable to install shear walls to prevent this.

When a multi-story shear wall is placed in a high-rise reinforced concrete building, its rigidity is considerably greater than that of other vertical members, and in general, the lowest floor leg of such a Support conditions are often designed as completely rigid.

(Occupational class to be solved by the invention) Therefore, in such a case, the lowest floor must bear most of the overturning moment due to the horizontal force, and the lowest floor's toppling resistance ′j! The load moment on Ma's legs becomes a very large value. For this reason, there is a problem in that a large amount of steel is required in designing the cross section, and the construction is very difficult.

On the other hand, there is not much difference in the behavior of the upper part of the structure due to differences in the degree of fixation of the base mirrors (legs) of this type of quay wall.

Figures 5 and 6 show distribution charts of the maximum response bending moment and the maximum response shear force during an earthquake of each layer of the shear wall due to differences in the degree of foundation fixation of this type of shear wall, and as can be seen from the above figures. 5. Even in the case of pin support, which is a case where the degree of fixation is extremely small, there is not much difference in the behavior of the upper part of the building due to the difference in the degree of fixation.

However, in the pin-supported state, a large reverse shearing force acts on the leg of the shear wall, which increases the shearing force borne by other vertical members.

From the above, the seismic performance required for the shear wall on the lower floor of the urn is as follows: (11) Sectional performance that does not cause yielding during wind loads or small to medium earthquakes; (+ii) Shear strength that is safe even against unexpected shear input; Cross-sectional properties that can be maintained include:

The present invention was proposed with the aim of solving these problems and providing a multi-layer shear wall with excellent seismic performance.

(Means for Solving the Problems) In order to achieve the above object, the multi-story shear wall according to the present invention divides the lowest floor portion into left and right halves at the center, and has column-shaped shear walls on both sides of each divided shear wall. At the same time, the legs are fixed to such an extent that reverse shearing does not occur.

(Function) As described above, in the multi-story earthquake-resistant wall according to the present invention, the lowest floor part is divided into left and right parts at the center, and pillar hoods are installed on both sides of each divided ``S'' wall. As a result, the cross-sectional performance is improved, yielding does not occur during wind loads and small to medium earthquakes, and the shear strength of each of the above-mentioned shear walls can be made comparable to that of a conventional single wall. , it is possible to ensure sufficient strength even against unexpected shearing inputs that pose a risk of layer collapse.

Furthermore, since the legs of the shear wall are fixed to such an extent that no reverse shear occurs, an increase in the shear forces borne by other vertical members is suppressed. Furthermore, as mentioned above, the behavior of the superstructure during an earthquake is almost the same as when the shear wall legs are completely fixed, so the earthquake resistance is good.

(Example) The present invention will be described below with reference to the illustrated embodiments.

The shear wall on the lowest floor of a high-rise reinforced concrete building is divided into two left and right parts at the center, and pillars (2) are installed on both sides of the wall plate (1) of each shear wall (IA) divided in this way. At the same time, adjacent column types (21 (2
) A fireproof material such as an asbestos board (3) is inserted between the walls to ensure the integrity of the wall surface during regular use.

Further, the legs of each of the seismic walls (A) are fixed to such an extent that reverse shear does not occur.

When designing the above-mentioned shear walls, the wind load, □ cross-sectional design is carried out so that each shear wall (A) on the lowest floor does not undergo bending yield at least in the event of a small to medium earthquake, and the maximum Each of the internal shear wall legs of the lower floor undergoes bending yielding, causing rotation in the continuous wall legs. By doing this, the shearing force input to the shear wall on the lowest floor becomes relatively smaller than that on the floor immediately above, but this reduction must be borne by other vertical members. Increase the shear strength of the member.

According to the illustrated embodiment, columnar shapes (2) are provided on both sides of the wall plates (1) in each of the divided shear walls, thereby improving cross-sectional performance, and each shear wall (A) has It has a shear strength comparable to that of a conventional single wall, and can maintain sufficient strength even against unexpected shear input.

Furthermore, in the event of a major earthquake, the legs of each of the bottom floor shear walls (A) bend and yield, causing the legs to rotate.

FIG. 4 shows the case of the above embodiment, and FIG. 3 shows the case of the conventional single wall (B). As is clear from both figures,
The amount of axial strain of the compression column required to obtain the same amount of rotation CεC
In the case of the embodiment, compared to the conventional method, the amount of the difference can be reduced. Sufficient restraint reinforcement is arranged in the column type (2) provided on both sides of the wall plate (1) in the divided shear wall (A)K, but in the case of the illustrated example, the same Since the amount of axial strain of the column type (2) required to obtain the amount of rotation is approximately the same, the amount of constraint reinforcement can be within a sufficient range of reinforcement.

Furthermore, the seismic behavior of the superstructure is almost the same as in the case where the N-resistant wall legs are completely fixed as described in 5 above, so the seismic performance is good.

(Effects of the Invention) As described above, in the multi-layer shear wall according to the present invention, the lowest floor part of the multi-layer shear wall is divided into left and right parts at the center, and pillow-shaped parts are installed on both sides of the divided seismic wall. By doing so, the amount of axial strain required for the pillow-shaped wall to obtain the same amount of rotation of the shear wall leg is reduced compared to the case of a conventional single wall, and the I-reinforcement of the restraint reinforcement in the stud type The amount is within the range that is sufficient.

In addition, since the shear strength of the shear wall of the present invention can be made equivalent to that of a conventional single wall, it is sufficiently safe even against unexpected shear force inputs that pose a risk of layer collapse. Strength can be ensured.

Furthermore, according to the present invention, the division resistance jl! Since the cross-sectional area of the wall plate and pillow shape of the wall can be ensured sufficiently large, the falling phenomenon can be prevented.

Furthermore, according to the present invention, the divided shear wall zero leg portion is fixed to such an extent that no reverse shear occurs, which reduces the load moment on the leg portion, reduces the amount of steel used, and facilitates construction. At the same time, it is possible to suppress an increase in the shearing forces borne by other vertical members due to the generation of one reverse shearing force.

Furthermore, the behavior of the superstructure during an earthquake is almost the same as when the wall legs are completely fixed, so its earthquake resistance is improved.

[Brief explanation of the drawing]

Fig. 1 is a front view of a frame including an embodiment of the multi-layer shear wall according to the present invention, Fig. 2 is a view taken along the arrows ■-■ in Fig. 1, and Figs. 3 and 4 are respectively the conventional A comparative explanatory diagram of the fixing properties of each leg of the earthquake-resistant wall and the S-resistant wall of the present invention, and Figures 5 and 6 show the maximum response during an earthquake of each layer of the S-resistant wall due to the difference in the degree of fixation of the foundation, respectively. It is a distribution map of bending moment and maximum response shear force during an earthquake. (A)...Divided earthquake-resistant wall, (1)...Wall plate, (2
)・・・Pillow type

Claims (1)

[Claims] The lowest floor of the multi-story shear wall is divided into two left and right parts at the center, pillars are installed on both sides of each divided shear wall, and the legs are fixed to the extent that reverse shearing does not occur. Features a multi-layer earthquake-resistant wall.