JP2002348890A - Direct foundation structure of building built on steep slope and having great difference in foundation level - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foundation structure for preventing a decline of earthquake resistant safety of a slope and a building by difference in a foundation level of the building built on the steep slope and having great difference of several portions of stories in the foundation level. SOLUTION: A foundation section 2 on the lower side of the foundation level is set on the ground 4 under the slope as a direction foundation, and a foundation section 3 on the higher side thereof is set on the ground 5 on the slope by using a rigidity adjusting mechanism. By setting a rigidity value of the rigidity adjusting mechanism 8, horizontal force at right angles to the slope inputted in the foundation section 3 on the slope is reduced, and torsional vibration of the building is prevented by horizontal force in the direction parallel with the slope to reduce couple acting on the foundation section 3 on the slope resulting from the torsional vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a direct foundation structure of a building which is built on a steep slope as shown in FIG. The present invention relates to a foundation structure for preventing a decrease in the seismic safety of slopes and buildings due to differences in foundation levels.

[0002]

2. Description of the Related Art Conventionally, when a foundation of a building that is built on a steep slope and whose foundation level is large in the vertical direction and differs by several floors is directly constructed by a foundation structure, the seismic safety of the slope and the building due to the difference in the foundation level is considered. We have not yet heard the basic technology to prevent the decline in sex.

However, as similar techniques, there are known techniques described below. (1) The base structure of the seismic isolation structure described in Japanese Patent Application Laid-Open No. H10-184090 has a seismic isolation pit formed by digging down the ground, and a lower end of a column of a structure (building) is formed at the lower end of the seismic isolation pit. It extends to the bottom surface, and its lower end is configured to be slidable.

(2) The basic structure of a building described in Japanese Patent Publication No. 4-61934 is a structure in which a low-rise building and a high-rise building having different vibration characteristics during an earthquake are integrally formed. It is configured to reduce the vibration property difference.

By the way, as shown in FIG. 1, when the foundations 2 and 3 of a building which is built on a steep slope and whose foundation level is large and several floors are different from each other are directly installed on the ground surfaces 4 and 5 as a foundation. The rigidity of the building frame 1a composed of columns and beams below the foundation level K on the higher side and the foundation 3 on the slope.
The stiffness difference from the stiffness causes various problems in seismic safety. By the way, compared to the frame 1a, the foundation 3 on the slope is
The stiffness is much greater.

Therefore, when a horizontal force perpendicular to the slope 6 is applied to the building 1, the foundation 3 on the slope having a large rigidity against the horizontal force strongly resists, and as a result, the slope 6 collapses. There is a risk. Further, when a horizontal force in a direction parallel to the slope 6 is input to the building 1, the foundation 1 on the slope with high rigidity strongly resists, whereas the frame 1a with low rigidity.
When the torsional vibration is generated in the building 1 having the following, there is a risk that the torsional vibration causes a corner force to act on the base portion 3 on the slope and the slope 6 is also collapsed.

[0007] If the stability of the slope 6 is reduced to such an extent that there is a danger of collapse, the seismic safety of the building 1 is also reduced, and the building 1 may be collapsed.

[0008]

However, the above prior arts (1) and (2) are not constructed under the condition that the height difference between the base portions 2 and 3 differs by several floors in the first place, and the use of the slope ground is not possible. Not a technology. Therefore, it is built on steep slopes,
It does not correspond to the technology for reducing the rigidity difference between the rigidity of the frame 1a composed of columns and beams below the foundation level K on the higher side and the rigidity of the foundation 3 on the slope.

On the other hand, when the bases 2 and 3 which are erected on slopes and have significantly different foundation levels are installed directly on the ground surfaces 4 and 5 as a foundation, an earth anchor 7 is cast on the slope 6 as shown in FIG. It is also conceivable to secure the safety of the slope 6 and enhance the earthquake-resistant safety of the building 1 by strongly reinforcing the slope 6. However, this method is not a technique for reducing the above-described rigidity difference, and also has a problem that the cost increases due to the installation of the ground anchor 7.

Further, as shown in FIG. 5, a measure to reduce (adjust) the difference in rigidity by installing a seismic isolation device (laminated rubber) 8 on the upper and lower foundations 2 and 3 of the slope 6 is also conceivable. However, in order to install the seismic isolation device 8 on the foundation 2 below the slope, it is necessary to dig the ground surface 4 below the slope to construct the seismic isolation pit 9.
When the ground surface 4 is dug down to construct the seismic isolation pit 9, the slope of the slope 6 retreats by the dimension L as shown by the dotted line, so that the position of the foundation 3 on the slope is There is a drawback that the risk of the slope 6 being collapsed too high increases.

Although not shown in the drawings, it is also conceivable to take measures to install the seismic isolation device on a pillar on the middle floor above the foundation, directly using the foundation below the slope. However, installing seismic isolation devices on pillars on the middle floor is difficult to implement because there are many restrictions on the function and use of the building.

[0012] Accordingly, an object of the present invention is to provide a rigidity of a building frame composed of columns and beams below a foundation level on a higher side in a building which is built on a steep slope and whose foundation level is largely different from each other, A stiffness adjustment mechanism that can reduce the stiffness difference between the stiffness of the foundation on the slope and the stiffness is prepared and the appropriate stiffness value is set (adjusted). To provide a direct substructure that enhances performance.

A second object of the present invention is to provide a direct foundation for a building capable of sufficiently securing steep slopes on steep slopes having a large difference in height and having several floors, thereby making it possible to construct the building at low cost. Is to provide a structure.

[0014]

Means for Solving the Problems As means for solving the above-mentioned conventional problems, the direct foundation structure of a building according to the first aspect of the present invention, which is built on a steep slope and whose foundation level is greatly different, comprises: It is a direct foundation structure of a building that is built on a steep slope and has a significantly different foundation level.The foundation part with the lower foundation level is installed as the foundation directly on the ground below the slope, and the foundation part on the higher side is It is installed on the ground on the slope using a rigidity adjustment mechanism, and by setting the rigidity value of the rigidity adjustment mechanism, the horizontal force in the direction orthogonal to the slope input to the foundation on the slope is reduced. The torsional vibration of the building due to the horizontal force in the direction parallel to the above is prevented, and the corner force acting on the foundation on the slope due to the torsional vibration is reduced.

According to a second aspect of the present invention, in the direct foundation structure of a building according to the first aspect of the present invention, which is built on a steep slope, and has a significantly different foundation level, the rigidity adjusting mechanism includes a horizontal rubber material such as a laminated rubber. It is characterized by being constituted by a displacement absorbing mechanism.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments and Examples of the Invention The invention described in claims 1 and 2 is directed to a direct foundation of a building 1 which is built on a steep slope as shown in FIG. It is suitably implemented as a structure.

This direct substructure is shown schematically in FIG.
As described above, the foundation 2 on the lower side of the foundation level is installed as a foundation directly on the ground surface 4 below the slope, and the foundation 3 on the higher side has the rigidity adjustment mechanism 8 on the ground 5 on the slope. It is installed using. The upper and lower foundations 2 and 3 each have a direct foundation structure, but the foundation 3 on the slope is provided with a rigidity adjusting mechanism 8 directly on the foundation 10 to adjust rigidity and allow horizontal displacement. Therefore, it is a so-called mixed direct basic structure.

The stiffness adjusting mechanism 8 is constituted by, for example, a horizontal displacement absorbing mechanism made of a laminated rubber or the like (the invention according to claim 2). The allowable horizontal deformation assumes a large earthquake,
Approximately 1/100 or more of the difference between the basic levels is used as a guide. The stiffness value is set so that even if a horizontal force in a direction parallel to the slope 6 is input to the building 1, no torsional vibration occurs in the building 1, that is, the building 1 vibrates in parallel at each height level. Set to a possible stiffness value. The allowable vertical axial force is configured to secure an allowable vertical axial force that is equal to or greater than the axial force at the time of an earthquake that occurs on the foundation 3 on the slope.

By setting the stiffness value of the stiffness adjusting mechanism 8 as described above, the horizontal force in the direction orthogonal to the slope 6 input to the building 1 via the foundation 3 on the slope is reduced, and Since the torsional vibration of the building 1 due to the horizontal force in the direction is prevented and the corner force acting on the foundation 3 on the same slope due to the torsional vibration is reduced, the building 1 is As a whole, it vibrates equally in the direction parallel to the horizontal force. In this manner, the rigidity of the base portion 3 on the slope is reduced by the rigidity adjusting mechanism 8 to reduce the resistance value, so that the collapse of the slope 6 can be prevented.

That is, when a horizontal force orthogonal to the slope 6 is input to the building 1, the rigidity adjusting mechanism 8 is horizontally deformed to reduce the apparent rigidity of the foundation 3. Therefore, the difference in rigidity between the rigidity of the foundation 3 and the rigidity of the building frame 1a below the foundation level K on the higher side can be reduced (approximated), and the foundation 3 can respond to the horizontal force. Do not strongly resist.

Also, even if a horizontal force parallel to the slope 6 is applied to the building 1, the rigidity adjusting mechanism 8 is set to a rigidity value such that the torsional vibration of the building 1 is not deformed. The building 1 vibrates in parallel at each level.
That is, torsional vibration does not occur in the building 1, and the corner force acting on the foundation 3 on the slope due to the torsional vibration can be reduced or solved.

Therefore, the stress on the ground on the slope is reduced to prevent the slope 6 from collapsing, and the stability of the slope 6 is ensured.
As a result, the seismic safety of the building 1 can be improved.

FIG. 3 shows the response analysis result of the building 1 using the above-mentioned direct foundation structure (so-called mixed direct foundation structure) during an earthquake, and the effect of the direct foundation structure is confirmed.

The upper and lower foundations 2 and 3 are respectively
The response shear force at each floor level (each plot of the black triangle in FIG. 3) of the building with the conventional direct foundation structure installed directly on the building 5 and the above-mentioned building 1 with the so-called mixed direct foundation structure of the present invention. The response shear force at each floor level (each open circle in FIG. 3) was compared. In this case, the conventional direct foundation structure has a sudden change in the response shear force near the foundation level on the higher side, and the value reaches about 4 × 10 ³ ton (4 × 10 ⁶ kg). . It is considered that the rapid change in the response shear force acts on the ground on the slope to reduce the stability of the slope and to reduce the seismic safety of the building.

On the other hand, in the building 1 having the mixed direct foundation structure of the present invention, since there is no sudden change in the response shear force as described above, the stability of the slope 6 is ensured, and the seismic safety of the building 1 is improved. It can be confirmed that it is high. For this reason, it is not necessary to lay a ground anchor on the slope 6 to reinforce it, which greatly contributes to cost reduction.

In addition, by adopting the mixed direct foundation structure, it is not necessary to dig the ground surface 4 under the slope 6 to construct the seismic isolation pit 9, so that the slope of the slope 6 retreats and the slope 6
The stability of is not impaired.

Moreover, the structure is simple, and it is possible to construct the building 1 on a steep slope regardless of the height difference of the foundation level and the structure of the building.

[0028]

According to the first and second aspects of the present invention, in a direct foundation structure of a building which is built on a steep slope and has a significantly different foundation level, a rigidity adjusting mechanism is installed on a foundation portion on the slope. Thereby, the apparent rigidity of the foundation portion on the slope is reduced, and the rigidity difference between the rigidity of the foundation portion and the rigidity of the building frame below the foundation level on the higher side can be reduced (approximated). .

Therefore, it is possible to prevent the collapse of the slope by reducing the stress on the ground on the slope, to secure the stability of the slope, and to improve the seismic safety of the building.

Moreover, the present invention has a simple structure, is easy to implement and is inexpensive, and makes it possible to construct a building using a steep slope regardless of the height difference of the foundation level and the structure of the building. enable.

[Brief description of the drawings]

FIG. 1 is an elevational view showing a building that is built on a steep slope where the inventions described in claims 1 and 2 are implemented, and has a large foundation level and is different for several floors.

FIG. 2 is an elevational view schematically showing a direct foundation structure of a building according to the first and second aspects of the present invention, which is built on a steep slope and has a significantly different foundation level.

FIG. 3 shows a response analysis result of a building having a mixed direct foundation structure during an earthquake.

FIG. 4 is an elevational view conceptually showing a conventional building constructed on a steep slope where a foundation part having a large foundation level and differing by several floors is directly installed on a ground surface as a foundation.

FIG. 5 is an elevational view conceptually showing a building in which seismic isolation devices are installed on foundations above and below a slope to prevent torsional vibration and the like of the building.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Building 1a The following frames from the high foundation level 2 The foundation part of the low foundation level (below the slope) 3 The foundation part of the high foundation level (on the slope) 4 The ground surface under the slope 5 The ground on the slope Surface 6 Slope 8 Rigidity adjustment mechanism 10 Direct foundation K Higher foundation level

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Eiji Matsui, Inventor 10-10, Hashimotocho, Naka-ku, Hiroshima-shi, Hiroshima Prefecture Inside Hiroshima Branch of Takenaka Corporation (72) Inventor Satoru Aizawa 1-5, Otsuka, Inzai-shi, Chiba Pref. Address 1 Takenaka Corporation Technical Research Institute Co., Ltd. (72) Inventor Tomoyuki Tomoyuki 1-5-1, Otsuka, Inzai City, Chiba Prefecture 1-5-1, Takenaka Corporation Technical Research Institute Co., Ltd. (72) Inventor Masaaki Kakura 1-5-1, Otsuka, Inzai City, Chiba Pref. 1-5-1, Otsuka, Inzai City, Japan Takenaka Corporation Technical Research Institute (72) Inventor Keizo Iwashita 1-5-1, Otsuka, Inzai City, Chiba Pref. 2D046 DA00 DA13 F term in Takenaka Corporation Technical Research Institute

Claims (2)

[Claims] 1. A direct foundation structure for a building that is built on a steep slope and has a significantly different foundation level, wherein the foundation part on the lower foundation level is directly installed on the ground below the slope, and Is installed on the ground on the slope using a rigidity adjusting mechanism, and by setting the rigidity value of the rigidity adjusting mechanism, horizontal force in the direction orthogonal to the slope input to the foundation on the slope is reduced. And also
The foundation level on a steep slope is characterized by preventing torsional vibration of the building due to horizontal force parallel to the slope and reducing corner force acting on the foundation on the slope due to torsional vibration. The direct foundation of a very different building. 2. The direct connection of a building on a steep slope according to claim 1, wherein the rigidity adjusting mechanism is constituted by a horizontal displacement absorbing mechanism such as a laminated rubber. Foundation structure.