JP2662571B2 - Seismic building structure - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earthquake-resistant building structure having a good seismic effect against external force such as an earthquake. "Conventional technology and its problems" Conventionally, seismic design methods applied to building structures are designed to respond to external forces of a scale such as an earthquake that occurs relatively frequently.
The design method is such that the strength of each member and its structure are determined so that the stress generated in the members constituting the building structure is within the allowable stress level. Further, with respect to an external force of a magnitude such as the largest earthquake that is expected to occur within the useful life of the building structure, slight plastic deformation is allowed to members of the entire building structure. It has been acknowledged that there is no problem if the structure does not collapse, and this so-called plastic-oriented ultimate design method is being applied in practice. However, in the final design method, the position of the member to be plasticized, the degree of plasticization, and the like are not always clear. The present inventors have conducted intensive studies in view of the above problems, and as a result, have obtained the following findings. That is, according to the seismic limit design method based on the energy theory, the optimum distribution of the strength (yield shear force) of each layer of the building, in other words, the yield shear force coefficient distribution i in the i-th layer can be uniquely obtained. Is given by the following equation (Hiroaki Akiyama, "Seismic Extreme Design of Buildings", University of Tokyo Press). When the strength αi of a certain layer is smaller than the optimum distribution αi, energy of an external force due to an earthquake or the like is concentrated on this layer. Conversely, using this principle,
By appropriately adjusting the strength αi of each layer, the energy of the external force can be distributed to each layer at a desired ratio.
By reducing only the strength of the first layer of the building, external energy can be concentrated on the first layer. Furthermore, according to the above-described final design method, if external force energy concentrated on the first layer is absorbed by plastic deformation of the members of the first layer, external force energy transmitted to the second layer or more can be reduced. Therefore, it is possible to provide a seismic isolation effect for the entire building. In order to reduce only the strength of the first layer, the following method may be used. That is, provided that the cumulative plastic strain energy absorbed by the first layer is 95% or more of the total cumulative plastic strain energy, the strength of the second layer or more is given by the following equation with respect to the optimal distribution. If it is more than twice, energy from external force can be concentrated on this first layer (Hiroaki Akiyama, Architectural Institute of Japan Transactions, 341 ,
July 1984). Here, a: Strength magnification α ₁ : Yield shear force coefficient of the first layer αe ₁ : Yield shear force coefficient of the first layer at the limit at which the structure remains elastic Therefore, the present inventors have based on the findings described above. Concentrating energy from external force on at least one layer of the multi-layered building structure, suppressing the stress generated in the members constituting the building structure within the allowable stress level with respect to the small external force, And while allowing the yield of the member of the layer where the energy is concentrated against the large external force,
By allowing these members to absorb the energy of the external force by yielding the members, the amount of energy absorbed by the external force can be accurately grasped, and the degree of freedom in design increases, and the weight of the member such as a steel frame used is reduced. Proposing a building structure that can be reduced (Japanese Patent Application No. 61-227781). At this time, the layer on which the energy of the external force is concentrated is usually set to the first layer, and the members of this layer include a plasticizing member made of ordinary steel or the like that yields to the large external force, and a member for the large external force. And an elastic member made of high-strength steel or the like that behaves in the elastic region. That is, when a large external force is applied, the energy of the external force is absorbed by the plasticized member due to the plastic deformation of the plasticized member, so that the energy transmission to other layers is reduced. By maintaining the elastic state of the elastic member, the maximum deformation of the entire layer where the energy is concentrated,
While the increase in residual deformation is suppressed, the building structure is prevented from deteriorating due to the P-δ effect due to the generated horizontal deformation,
This is because the resilience is secured. By the way, as described above, the plasticizing member provided on the first layer, which is the energy concentration layer of the building structure, itself undergoes plastic deformation when a large-scale external force acts thereon as described above, thereby causing the entire building structure to be deformed. It is possible to replace it with a new plasticized member after such an external force acts because it provides a seismic isolation effect on the surface. However, since this plasticized member is usually fixed with its lower end (that is, column base) buried one by one in a reinforced concrete foundation beam, it is necessary to replace the deformed plasticized member. However, it is necessary to cut concrete around the column base of the plasticizing member, which may be very troublesome. In addition, this plasticized member should not be plastically deformed by normal external force, and it is desirable that it be plastically deformed only when a large-scale external force is applied. Therefore, its (bending) rigidity is quantitatively evaluated in advance. It is preferable that the structure has a good shape. However, as described above, if the column base is fixed while being buried in the reinforced concrete foundation beam, the concrete around the column base is also deformed simultaneously with the deformation of the plasticized member. ) It is also conceivable that quantitative evaluation of rigidity is difficult to perform. The present invention has been made in view of the above circumstances, and is intended to provide an earthquake-resistant building structure in which replacement of members after deformation due to an external force such as an earthquake is easy, and quantitative evaluation of member rigidity during the deformation is easy. The question is how to achieve it. "Means for solving the problems" Therefore, the present invention relates to a main body structural part which is a skeleton of a building structure, a base part installed in the ground, and an intervening part between the main body structural part and the base part, such as an earthquake. A deformation absorbing section configured to absorb the energy of the external force to suppress vibration of the main body structure section by being deformed by itself when an external force is applied, the deformation absorbing section includes: On the floor where the floor is formed on the upper surface of the base part, it is erected inside a space surrounded by columns and beams of the floor, and the upper part of the deformation absorbing part is attached to and detached from the upper part of the floor via a brace. A connection structure is fixed integrally with the deformation absorbing portion below the deformation absorbing portion, and the connection structure is fixed to the base by an anchor bolt embedded in the base portion. Being tightened against the department Accordingly, a lower portion of the deformation absorbing portion is detachably fixed to the base portion via the connection structure. Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 3 are views showing an earthquake-resistant building structure (hereinafter simply referred to as a building structure) according to a first embodiment of the present invention. In FIGS. 1 to 3, reference symbol A denotes a building structure constructed on the ground G. This building structure A is a building having a so-called steel frame structure, and includes columns 1, 1,... Made of rectangular steel pipe made of ordinary steel, and beams 2 made of H-shaped steel.
2,... Constitute a main body structure 3 as a skeleton. The pillar 1 is formed in a small-diameter portion 1a made of high-tensile steel whose diameter is reduced in the first floor F, which is the lowest floor of the building structure A. Reference numeral 4 denotes a reinforced concrete foundation beam (foundation) installed at a predetermined depth in the ground G,
The lower end of the column 1, that is, the column base is embedded and fixed in the foundation beam 4. The building structure A has a first layer F, that is, a floor formed at the level of the upper surface of the foundation beam 4 and a floor which is the lowest floor of the building structure A, and a square steel pipe made of ordinary steel. Plasticizing members (deformation absorbing parts) 5, 5 are provided. As shown in FIG. 3, these plasticizing members 5, 5 are arranged inside a space formed by columns 1, 1 of this floor and beams 2 erected above them. Two pieces are erected on the foundation beam 4 constituting the floor of this floor, and the upper ends of the plasticizing members 5, 5 are connected by a connecting member 6 made of H-section steel. The plasticizing members 5, 5
Is selected for its material and cross-sectional shape so that it yields with respect to an external force of the largest earthquake magnitude expected to occur during the service life of the building structure A. Thus, when an external force of the above scale is applied, the plasticizing members 5, 5 undergo plastic deformation, so that the energy of the external force is absorbed by these plasticizing members 5, 5. At the lower end portions of the plasticizing members 5, 5, a connecting structure 7 formed by connecting them horizontally is unitized and fixed integrally. As shown in FIGS. 1 and 2, the connecting structure 7 is made of H-shaped steel, and has web-shaped stiffeners 8, 8,... Formed at predetermined positions in the longitudinal direction. On the other hand, the plasticizing members 5 and 5 of the foundation beam 4
Anchor bolts 9, 9,... Buried vertically in the foundation beam 4 are provided such that their upper ends project from the upper surface of the foundation beam 4. Screws are engraved at both ends of the anchor bolt 9, and a plate-shaped anchor plate 10 is inserted into the lower end buried in the foundation beam 4. Nuts 11 up and down,
11 is fixed to the anchor bolt 9 by being screwed and tightened. Further, in the flange portion of the connecting structure 7, through holes 12, 12,... At positions facing the anchor bolts 9, 9,.
Are drilled. And these anchor bolts 9,
The upper ends of 9, ... are inserted into through holes 12, 12, ... of the connecting structure 7, and nuts 13, 13, ... are screwed to the upper ends of the anchor bolts 9, 9, ... and tightened. This allows
The plasticizing members 5 and 5 are detachably fixed to the foundation beam 4 via a connection structure 7. Further, the upper portions of the plasticizing members 5, 5 are detachably fixed to the upper portion of this floor via the brace 14. That is, a brace 14 made of a steel pipe made of ordinary steel or high-strength steel is extended from the plasticizing member 5 toward an intersection of the column 1 and the beam 2 via a mounting plate (not shown). ,
The brace 14 is attached to the beam 2 at the intersection by a gusset plate (not shown). The members (square steel pipe, H-shaped steel, steel pipe) constituting the building structure A have a stress generated by an earthquake-scale external force that is expected to occur several times during the service life of the building structure A. The material and the cross-sectional shape are selected so as to be within the allowable stress level. Further, the material and shape of the connecting structure 7 and the anchor bolt 9 are selected so as to be sufficiently rigid as compared with the plasticizing member 5. The plasticizing members 5 and 5 having such a configuration are arranged at predetermined positions of the building structure A in a unitized state in which the connecting members 6 and the connecting structures 7 are attached in advance. The upper end is attached to the brace 14, 14, and the through hole of the connecting structure 7 at the lower end.
The upper ends of the anchor bolts 9, 9, ... projecting from the upper surface of the foundation beam 4 are inserted into 12, 12, ..., and nuts 13, 13, ... are screwed into these anchor bolts 9, 9, ... with a predetermined tension. By being tightened, it is detachably fixed to the foundation beam 4. Therefore, in the building structure A having the above configuration, since the diameter of the pillar 1 is reduced in the first layer F, there is a difference between the strength of the first layer F and the strength of the other layers. As a result, when an external force such as an earthquake is applied to the building structure A, energy from the external force is concentrated on the first layer F thereof. Therefore, when an external force of an earthquake scale expected to occur several times during the useful life of the building structure A is applied, each member centering on the first layer F behaves within the elastic range in the restoring force characteristic. Becomes Also, when an external force of the largest earthquake magnitude expected to occur during the useful life of the building structure A is applied, the energy of the external force is transmitted to the plasticizing members 5, 5 via the brace 14. Thereby, the plasticizing members 5 and 5 yield. As a result, most of the energy of the external force is absorbed as plastic strain energy in the first layer F, so that the energy transmitted to the further layers is reduced, and the seismic effect on the entire building structure A is thus reduced. Can be obtained. In addition, the column 1 maintains its elastic state against the external force of the largest earthquake scale due to its own large elastic deformation capacity, thereby maximally deforming the entire energy concentration layer (first layer F) and residual deformation. Suppress the increase. In addition, the building structure A is prevented from being deteriorated by the P-δ effect due to the generated horizontal deformation, and the restoring force is secured. Then, when the plasticizing members 5, 5 are plastically deformed by the application of the external force in this way, the nuts 13, 13,.
By loosening the connection member 7, the fixing of the plasticizing member 5 to the foundation beam 4 is released, and at the same time, the fixing to the braces 14, 14 is released, so that the plasticizing members 5, 5 are connected to the connecting member 6. The entire structure 7 is removed. Then, the new plasticizing members 5, 5 unitized by attaching the connecting member 6 and the connecting structure 7 in advance are arranged at the same position, and the upper ends thereof are attached to the braces 14, 14, and the lower ends thereof are attached. A certain connecting structure 7 is fixed to the foundation beam 4 by screwing and tightening of anchor bolts 9, 9,... And nuts 13, 13,. That is, fixing of the plasticizing members 5, 5 to the foundation beam B is as follows.
Since the nuts 13, 13,... Are screwed and tightened to the connecting structure 7 and the anchor bolts 9, 9,. Even if it becomes necessary to replace 5, the replacement work is very simple. In particular, by integrating the plasticizing members 5, 5 and the connecting member 6 and the connecting structure 7 in advance and forming them as a unit, they can be handled collectively at the time of replacement work, and The workability is superior to the case where they are individually assembled.
Moreover, as described above, the plasticizing members 5, 5 are installed on the foundation beam 4, and the lower portion thereof is detachably fixed to the foundation beam 4 via the connecting structure 7, and the plasticizing member
Since the upper part of 5,5 is detachably fixed to the upper part of the floor via the braces 14,14, the work related to the replacement of the plasticizing members 5,5 can be freely and easily performed on the floor of the installation floor. It is possible to do. It should be noted that it is conceivable to install the plasticized members 5, 5 under the floor or in a foundation pit, for example.
In such a case, the work relating to the replacement of the plasticizing members 5, 5 must be performed under the floor or in a narrow space in the foundation pit, which is not preferable in view of workability. The material and shape of the connecting structure 7 and the anchor bolt 9 are selected so as to be sufficiently rigid as compared with the plasticizing members 5 and 5. 7 can be considered as completely fixed at the upper end,
Bending rigidity of the connection structure 7, axial rigidity of the anchor bolt 9,
By grasping the elasticity, the rigidity of the plasticizing members 5, 5 can be quantitatively evaluated. The shape, dimensions, and the like of the earthquake-resistant building structure of the present invention are not limited to the above-described embodiment, and various modifications are possible. As an example, if there is a problem that the connecting structure 7 protrudes to the upper surface of the foundation beam 4, as shown in FIG.
The portions corresponding to the plasticizing members 5 and 5 may be formed low. [Effects of the Invention] As described above in detail, according to the present invention, the deformation absorbing portion is provided upright on the floor immediately above the base portion inside the space surrounded by the columns and beams of the floor, and the deformation absorbing portion is provided. The upper part of the part is detachably fixed to the upper part of the floor via a brace, and the connecting structure is integrally fixed to the lower part of the deformation absorbing part, and the connecting structure is embedded in the base part. Since the lower portion of the deformation absorbing portion is detachably fixed to the base portion via the connection structure by being tightened to the base portion by the anchor bolt, the deformation is caused by an external force such as an earthquake acting. Even if the absorber is deformed and needs to be replaced, the replacement can be freely and very easily performed on the floor of the installation floor. In addition, since the deformation absorbing portion can be considered to be completely fixed at the upper end of the connecting structure, the bending rigidity of the connecting structure, the axial rigidity and the elasticity of the anchor bolt can be grasped, and the deformation absorbing portion can be considered. The rigidity can be quantitatively evaluated. Therefore,
ADVANTAGE OF THE INVENTION According to this invention, the replacement | exchange of the member after deformation | transformation by external force, such as an earthquake, is easy, and also the seismic-resistant building structure in which quantitative evaluation of the member rigidity at the time of the deformation is easy is realizable.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to FIG. 3 are views showing an earthquake-resistant building structure according to one embodiment of the present invention, and FIG. 1 shows a base portion and a mounting portion of a deformation absorbing portion. FIG. 2 is a front view, FIG.
FIG. 3 is a schematic front view showing the whole of the building structure, and FIG. 4 is a front view showing a mounting portion of a base portion and a deformation absorbing portion of an earthquake-resistant building structure according to another embodiment of the present invention. A: Building structure (earthquake-resistant building structure), 1 ... pillar, 2 ...
... beam, 3 ... body structure part, 4 ... foundation beam (foundation part), 5
... plasticizing member (deformation absorbing part), 7 ... connecting structure part, 8
... stiffener, 9 ... anchor bolt, 10 ... anchor plate (fixing plate), 11 ... anchor plate fixing nut, 14 ... brace.

Continuation of front page    (72) Inventor Kibe Yabe               Shimizu, 2-6-1 Kyobashi, Chuo-ku, Tokyo               Construction Co., Ltd. (72) Inventor Toshihiko Hirama               Shimizu, 2-6-1 Kyobashi, Chuo-ku, Tokyo               Construction Co., Ltd. (72) Inventor Shinji Mase               Shimizu, 2-6-1 Kyobashi, Chuo-ku, Tokyo               Construction Co., Ltd. (72) Inventor Kiyoshi Ikura               Shimizu, 2-6-1 Kyobashi, Chuo-ku, Tokyo               Construction Co., Ltd.                (56) References Shokai Sho 62-648 (JP, U)

Claims (1)

(57) [Claims] The main body structure, which is the skeleton of the building structure, and the foundation installed in the ground, and are interposed between the main body structure and the foundation, and are deformed when an external force such as an earthquake is applied. And a deformation absorbing part that suppresses vibration of the main body structure part by absorbing energy of the main body part, wherein the deformation absorbing part is on a floor where a floor is formed on an upper surface of the base part. It is erected inside the space surrounded by the columns and beams of the floor, and the upper part of the deformation absorbing part is detachably fixed to the upper part of the floor via a brace, and the upper part of the deformation absorbing part is A connection structure is fixed integrally with the deformation absorbing portion at a lower portion, and the connection structure is tightened against the base portion by an anchor bolt embedded in the base portion, whereby the deformation absorption portion is fixed. The lower part of the part is via the connecting structure An earthquake-resistant building structure characterized by being detachably fixed to the foundation.