JP3779797B2 - Seismic isolation system for steel frame ramen construction - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seismic isolation method for a building having a steel frame ramen frame.
[0002]
[Prior art]
The principle of seismic isolation in buildings is to increase the natural period of the building so that ground vibrations caused by the earthquake are not transmitted to the building. Specifically, a measure for interposing a seismic isolation device between a building and the ground and lengthening the natural period of the building is considered.
[0003]
As an example of the seismic isolation structure of a steel frame ramen building, for example, as shown in FIG. 6 (a), a seismic isolation device 52 is arranged directly below a column 51 constituting the building and is installed on the ground 53 and the column. A structure in which the lower end of 51 is connected by a floating beam 54 made of steel concrete, precast concrete or reinforced concrete, or as shown in FIG. There is known a structure in which a bottom plate 55 is provided, and the bottom plate 55 is supported by a seismic isolation device 52 installed on the ground 53 without being restricted by the installation position of the column 51.
[0004]
In each of the above seismic isolation structures, the natural period of the building also depends on the weight of the structure installed on the upper part of the seismic isolation device 52, and the period increases as the weight of the structure increases. For this reason, in a seismically isolated building, the weight is gained by the floating beams 54 and the bottom plate 55 made of steel concrete, precast concrete, or reinforced concrete that mutually connect the lower ends of the columns 51.
[0005]
[Problems to be solved by the invention]
In the above seismically isolated building, floating beams made of steel concrete, precast concrete or reinforced concrete are used for the purpose of increasing the weight, so only the floating beams are different from the beams on the upper floor even though they are made of steel frames. There are problems that it takes a structure and takes a lot of construction work, a problem that construction job types increase, and material procurement becomes complicated.
[0006]
Furthermore, since the storage of the detailed part is different from other floors, the exterior materials and interior materials have to be made differently from the other floors.
[0007]
In particular, in the structure of FIG. 6 (b), the load acting on each column is transmitted to the seismic isolation device via the bottom plate, so that it is necessary to increase the strength of the bottom plate compared to the structure of FIG. 6 (a). Thus, the bottom plate has a completely different structure from the beam on the upper floor, and there are problems that it takes a lot of construction work, a problem that construction job types increase, and a problem that material procurement becomes complicated.
[0008]
An object of the present invention is to provide a steel frame ramen-based seismic isolation method that can solve the above-mentioned problem by making all the upper structure of the seismic isolation device a steel frame ramen structure.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the seismic isolation method for steel framed ramen construction according to the present invention is a seismic isolation method for steel framed ramen construction which is a prefabricated building frame, directly below the columns of the individual rectangular steel pipes constituting the frame. Only, a seismic isolation device connected to a rigid solid foundation arranged on the ground or a reinforced concrete beam that is a continuous footing and supported by a foundation located higher than the reinforced concrete beam is provided on the column and the foundation. A steel beam of H-shaped steel, which is provided in accordance with the core and has the same height and width or cross-sectional shape as the second floor beam that forms the frame, is connected to the side of the column between the lower ends of the columns. The connected part is fixed to the upper part of the seismic isolation device to form a housing.
[0010]
In the steel frame ramen-based seismic isolation method, a seismic isolation device is provided directly below the steel frame frame, and the seismic isolation device is supported by a reinforced concrete beam arranged on the ground. Because it is connected with, the superstructure of the seismic isolation device can be unified into a steel structure, and the construction occupations will not increase.
[0011]
In particular, the principle of seismic isolation is that the natural period of the building is made larger than the natural period of the ground shaking caused by the earthquake and the difference is increased so that the ground shaking caused by the earthquake is not transmitted to the building. . Therefore, by improving the rigidity of the ground by placing reinforced concrete beams on the ground, the natural period of the ground at the time of an earthquake becomes shorter than the natural period in the absence of reinforced concrete beams, increasing the weight of the building. Even without it, it can demonstrate seismic isolation effect.
[0012]
In addition, since the height and width or cross-sectional shape from the lower surface to the upper surface of the steel beam connecting the lower ends of each column is connected by the same H-shaped steel beam as the second floor beam, the lower end of each column There is no increase in labor when constructing steel beams (hereinafter referred to as “floating beams”) that connect them.
[0013]
Since steel-framed ramen is a prefabricated building, a seismic isolation device supported by reinforced concrete beams placed on the ground is provided directly below each column, and each column is connected by a floating beam. A seismic isolation structure can be obtained without increasing the construction job and labor.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment of the seismic isolation method for steel frame ramen construction will be described with reference to the drawings. FIG. 1 is a perspective view illustrating the structure of a steel frame structure according to the present invention, FIG. 2 is a diagram illustrating the structure of the lower end portion of a steel frame structure, FIG. 3 is a plan view of FIG. 2, and FIG. It is sectional drawing explaining the example of.
[0015]
The seismic isolation structure of the steel frame structure according to the present embodiment is provided with a seismic isolation device B supported by a reinforced concrete beam C arranged on the ground directly below each column 1 constituting the steel frame frame structure A. The lower end of the column 1 is connected by a steel floating beam D. Thus, the rigidity of the ground is increased by arranging the reinforced concrete beams C on the ground, and thereby the natural period of the ground due to the earthquake is shortened. For this reason, even if the weight of the frame A supported on the upper part of the reinforced concrete beam C via the seismic isolation device B is not significantly increased, a large seismic isolation effect can be obtained by increasing the difference from the natural period of the ground. Is possible.
[0016]
The housing A includes a plurality of pillars 1 arranged at predetermined positions and beams 2 arranged corresponding to the respective floors, and these pillars 1 and the beams 2 are rigidly connected. As long as the frame A is made of steel frame ramen, the structure is not particularly limited.
[0017]
However, by constructing the case A as a so-called prepub building that was "assembled by a systemized construction method using mass-produced frame parts," the number of parts and construction jobs including the floating beam D increased. It is possible to achieve seismic isolation of the building without causing any significant increase in cost. For this reason, in the present Example, the housing A is comprised as a housing of a prefab building.
[0018]
In the case A, the column 1 is configured by using a square steel pipe having a size set in advance in the design stage, and the beam 2 is similarly made of an H-section steel having a size set in advance in the design stage. It is configured using.
[0019]
As the seismic isolation device B, it is possible to select and use a conventional laminated rubber type, a sliding friction type shown in FIG. 5 (a), or a rolling friction type shown in FIG. 5 (b). It is. However, it is preferable to use a seismic isolation device of a type that can increase the natural period of the structure even if the upper structure is lightweight. As such a seismic isolation device, there is one configured to have an initial stiffness and a secondary stiffness so as to lower a yield shear force coefficient.
[0020]
The reinforced concrete beam C is disposed on the ground, and is configured so as to be able to exhibit high rigidity by integrally connecting the foundations 3 installed at predetermined positions. The reinforced concrete beam C may be a so-called reinforced concrete beam configured by placing reinforcing bars on site and placing concrete, or may be a so-called precast concrete beam manufactured in advance.
[0021]
The reinforced concrete beam C is not limited as long as it has a function as a beam. That is, as shown in FIG. 2, it may be configured as a solid foundation 3 a, and as shown in FIG. 4, it is a continuous footing in which a footing 3 b installed adjacently is connected by a reinforced concrete beam C. There may be.
[0022]
As described above, the solid foundation 3a constructed integrally with the reinforced concrete beam C arranged on the ground is constituted, or the adjacent footing 3b is connected and integrated by the reinforced concrete beam C arranged at the same level as the ground. By configuring the continuous footing, these foundations exhibit high rigidity, and the natural period of ground shaking due to an earthquake can be shortened.
[0023]
The floating beam D connects and integrates the lower ends of the columns 1 of the adjacent frame A, and is configured as a steel beam. For this reason, it is possible to manufacture at the factory stage in substantially the same process as the beam 2 of the casing A, and it is possible to manufacture without increasing the construction job type and complicating the process.
[0024]
A load on the first floor acts as a distributed load on the floating beam D. That is, the floating beam D is subjected to a bending load that is substantially the same as that of the second floor floor beam 2 made of H-shaped steel. For this reason, the cross-sectional shape of the floating beam D is set so that the cross-sectional secondary moment becomes the same value as the cross-sectional secondary moment of the floor beam 2 on the second floor.
[0025]
Moreover, it is preferable that the height and width of the floating beam D are equal to the height and width of the floor beam 2 on the second floor. By setting the floating beam D to the above-mentioned size, it is possible to make the accommodation of the beam D substantially the same as the floor beam 2 on the second floor, and make the specifications of the interior material and exterior material, or the construction method substantially the same. It becomes possible. In consideration of the dimensional condition and the condition of the moment of inertia of the cross section, the floating beam D can be an H-section steel or a square steel pipe having a thickness different from that of the floor beam 2.
[0026]
However, when considering the problem of material procurement and inventory, it is desirable that the floating beam D has the same cross section as other beams, particularly the floor beam 2 on the second floor. Thus, even if the floating beam D is made of the same material as that of the floor beam 2 on the second floor, there is no problem in strength as long as the acting load is equivalent.
[0027]
【The invention's effect】
As explained in detail above, in the seismic isolation method for steel framed ramen construction according to the present invention, a seismic isolation device is provided directly below a column constituting the steel frame frame structure, and the seismic isolation device is provided by a reinforced concrete beam arranged on the ground. In addition, since the lower ends of each column are connected by a steel beam, the upper structure of the seismic isolation device can be unified into a steel structure. For this reason, a reinforcing bar and a cement worker are unnecessary, and it does not increase a construction job type and does not require construction labor. Furthermore, since it is unified with steel structure, the procurement of materials can be simplified.
[0028]
In particular, by placing reinforced concrete beams on the ground, it is possible to improve the rigidity of the ground, so that the natural period of the ground during an earthquake is shorter than the natural period in the absence of reinforced concrete beams, Even without increasing the weight, the seismic isolation effect can be demonstrated.
[0029]
Further, by making the height dimension and width dimension or cross-sectional shape of the steel beam (floating beam) the same as the cross-sectional shape of the second-floor floor beam, the detailed shape of the steel beam is the same as that of the second floor. It will be steel, so the number of construction jobs will not increase, construction will not take much time, and interior and exterior materials will be the same as the upper floor, making it possible to simplify material procurement, reducing costs and Shortening can be achieved.
[0030]
In addition, by using a steel frame ramen as a prefabricated building frame, it is possible to realize a seismic isolation structure without increasing the number of construction jobs and labor for the prefabricated building. In other words, prefabricated construction is designed to reduce the cost by mass production by sharing parts as much as possible. Therefore, by making the steel beam the same as the floor beam on the second floor, it is possible to realize a seismic isolation method that simplifies material procurement and reduces costs.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating a structure of a steel frame ramen structure according to the present invention.
FIG. 2 is a diagram for explaining a configuration of a lower end portion of a steel frame frame.
FIG. 3 is a plan view of FIG. 2;
FIG. 4 is a cross-sectional view illustrating an example of a reinforced concrete beam.
FIG. 5 is a diagram illustrating an example of a seismic isolation device.
FIG. 6 is a diagram illustrating a conventional seismic isolation structure.
[Explanation of symbols]
A Frame B Seismic isolation device C Reinforced concrete beam D Floating beam 1 Column 2 Beam, floor beam 3 Foundation 3a Solid foundation 3b Footing

Claims (1)

It is a seismic isolation system with a steel frame ramen that is a prefabricated building,
Basis only directly below the pillar of each square steel constituting the precursor Oite, are integrated by connecting the reinforced concrete beams is solid basis or a continuous footing rigid placed on the ground and at a higher position than the reinforced concrete beams The seismic isolation device supported by the base is provided in accordance with the pillar and the core of the foundation , and the height and width or the cross-sectional shape is the same as that of the second-floor beam constituting the frame between the lower ends of the pillars. the connection part steel beam of H shaped steel is connected to the side surface of the pillars, steel Frame Structures of Base Isolation construction, characterized in that the fixed skeleton on top of the seismic isolation device is configured.

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