JP2022107473A - Base isolator foundation structure and method for constructing the same - Google Patents

Abstract

To provide a base isolator foundation structure which enables a highly accurate installation work on a foundation while achieving rationalization of a construction work of the foundation at a site where a base isolator is installed, and a method for constructing the same.SOLUTION: Body concrete 40 made of cast-in-place concrete is formed so as to include: a precast concrete base isolator support plate 20 which is joined to a lower flange 3 of a base isolator 1, and in which dowel members are arranged so as to project from a lower surface; and a support leg 30 whose upper part is fixed and held by the base isolator support plate 20, which has a mounting bolt 31 for joining the base isolator 1 on an upper end side and a leg length adjusting bolt 33 on a lower end side, and in which the base isolator 1 is held in a self-supporting manner on a foundation slab 5.SELECTED DRAWING: Figure 1

Description

The present invention relates to the seismic isolation isolator foundation structure and its construction method, so that the seismic isolation isolator can be installed accurately on the foundation structure while rationalizing the foundation construction work at the site where the seismic isolation isolator is installed. Regarding the seismic isolation isolator foundation structure and its construction method.

As an example of the installation method of the basic structure of the conventional seismic isolation isolator (seismic isolation device), the seismic isolation device disclosed in Patent Document 1 and the installation method thereof have been proposed. In the method of installing the seismic isolation device disclosed in Patent Document 1, the seismic isolation device is installed by fixing the precast concrete board on which the seismic isolation device is placed on the foundation slab using a reinforcing bar with a fixing plate. It is possible to eliminate the need for a base plate when doing this, reducing construction costs, improving workability, and improving the quality of the seismic isolation foundation structure.

However, since the precast concrete board used for the foundation structure disclosed in Patent Document 1 is a full precast concrete product, it is heavy and is used for handling at a manufacturing factory, transportation to a site, installation at a site, and the like. The burden is heavy. In addition, in order to maintain the installation accuracy of the seismic isolation device installed on the precast concrete board and to secure the fixed state of the precast concrete board, to the installation surface of the precast concrete board and the fixing part of the reinforcing bar with the fixing plate. Grout work is required, and installation work is complicated.

Therefore, it has been proposed to reduce the weight of the foundation structure by adopting a hybrid structure of a half precast concrete plate and cast-in-place concrete for the foundation of the seismic isolation device (Patent Document 2).

In the mounting structure of the seismic isolation device disclosed in Patent Document 2, the lower base plate 6 that supports the seismic isolation device is supported on the level adjustment frame 7 that is previously constructed in the concrete placing space 2a of the lower pedestal 2. There is. Then, concrete is cast up to the height of the lower surface of the lower base plate 6 in the concrete casting space 2a. Also in the case of Patent Document 2, since a gap is generated between the lower surface of the lower base plate 6 and the upper surface of the lower pedestal 2, the grout 15 fills the gap between the lower base plate 6 and the upper surface of the lower pedestal 2. Is injected.

Japanese Unexamined Patent Publication No. 2011-32759 JP-A-2007-77617

As mentioned above, by adopting a hybrid structure of half precast concrete slab and cast-in-place concrete for the foundation of the seismic isolation device, the labor of on-site work such as transportation and installation of the heavy seismic isolation structure foundation can be reduced. However, even with the mounting structure disclosed in Patent Document 2, high precision is still required for the installation work of the lower base plate on the foundation and the installation work of the seismic isolation device on the lower base plate. Work requires multiple steps.

Further, in order to achieve close contact between the lower surface of the lower base plate and the upper surface of cast-in-place concrete, filling work with grout 15 is also required. Therefore, it is required to reduce the process of installation work at the site and improve the productivity by improving the construction efficiency.

Therefore, an object of the present invention is to solve the problems of the above-mentioned conventional techniques, and to reduce the number of steps of the installation work of the seismic isolation isolator at the site, and to perform the installation work with high accuracy. The purpose is to provide a structure and a method for constructing the structure.

A seismic isolation isolator support plate made of precast concrete, which is joined to the lower flange of the seismic isolation isolator and the dowel members are arranged so as to protrude from the lower surface.
The upper part is fixedly held by the seismic isolation isolator support plate, the seismic isolation isolator has a fastening portion for joining the seismic isolation isolator on the upper end side, and a leg length adjusting portion on the lower end side. It is a seismic isolation isolator basic structure provided with various support legs, and is characterized in that a main body concrete portion for supporting the seismic isolation isolator is formed so as to include the seismic isolation isolator support plate and the support legs. ..

The seismic isolation isolator support plate preferably has a gradient formed on the lower surface thereof.

The dowel member is preferably a reinforcing bar held and arranged so as to protrude from the lower surface.

The support leg is made of a long nut, and a fixing bolt for fixing the seismic isolation isolator to the seismic isolation isolator support plate is screwed into the upper female screw portion, and the seismic isolation isolator support plate is screwed to the lower end female screw portion. It is preferable that a leg length adjusting bolt that is self-supporting is screwed onto the base plate.

As a method for constructing the seismic isolation isolator foundation structure, a seismic isolation isolator support plate made of precast concrete in which dowel members are arranged so as to project from the lower surface is joined to the lower flange of the seismic isolation isolator to support the seismic isolation isolator. The seismic isolation isolator is independently held at a predetermined position on the foundation plate by adjusting the installation height by the leg length adjusting portion of the support leg whose upper part is fixedly held on the plate, and the seismic isolation isolator support plate and the support leg are held together. It is characterized in that the main body concrete supporting the seismic isolation isolator is placed so as to include the seismic isolation isolator.

According to the present invention, it is possible to accurately install the seismic isolation isolator on the foundation structure while rationalizing the work of constructing the foundation at the site where the seismic isolation isolator is installed.

The front view which showed the structure in the embodiment which applied the seismic isolation isolator foundation structure of this invention to a laminated rubber bearing in the cross section. The plan view and the side view which showed the structural example of one Embodiment of the seismic isolation isolator support plate used for the seismic isolation isolator basic structure shown in FIG. The partially enlarged sectional view which showed the example of the dowel shape formed on the lower surface of the seismic isolation isolator support plate of this invention. The partial cross-sectional view which showed the structural example of the plate mounting bolt attached to the seismic isolation isolator support plate of this invention. FIG. 3 is a partial cross-sectional view showing a configuration example of a joint reinforcing means for a seismic isolation isolator support plate and a seismic isolation isolator of the present invention. The partial cross-sectional view which showed the structural example of the auxiliary adjustment means of the support leg length attached to the seismic isolation isolator support plate of this invention. The work order explanatory drawing which showed each work procedure in the method of constructing the seismic isolation isolator foundation structure of this invention. The front view which showed the structure in the embodiment which applied the seismic isolation isolator foundation structure of this invention to a sliding bearing by the cross section.

Hereinafter, a seismic isolation isolator basic structure of the present invention and a mode for carrying out the construction method thereof will be described with reference to the accompanying drawings.

FIG. 1 shows the internal configuration of the seismic isolation isolator basic structure 10 that supports the seismic isolation isolator 1 and the seismic isolation isolator 1 of the present invention on the foundation plate 5. The seismic isolation isolator 1 used in the present invention comprises a known natural rubber-based laminated isolator having a columnar laminated rubber portion 2 having an outer diameter of 1,200 mm. Flange steel plates 3 and 4 are attached to the upper and lower surfaces of the laminated rubber portion 2 by mounting bolts 31 (not shown) in order to sandwich and hold the laminated rubber portion 2 from above and below. The flange steel plates 3 and 4 of the present embodiment are square flanges having a substantially square shape in a plan view, and one side thereof is 1,500 mm. It is also preferable that the flange steel plate is a circular flange having a predetermined diameter.

As shown in FIG. 1, the seismic isolation isolator 1 of the present invention is installed on the seismic isolation isolator foundation structure 10 constructed on the foundation plate 5, and the seismic isolation isolator foundation structure 10 is shown in the figure. As shown, the seismic isolation isolator support plate 20 is fixed to the lower surface of the lower flange 3 of the seismic isolation isolator 1 via the mounting bolts 31 of the four support legs 30. Further, the entire seismic isolation isolator support plate 20 is embedded in the main body concrete 40, and the seismic isolation isolator support plate 20 does not appear on the upper surface of the seismic isolation isolator foundation structure 10, and the seismic isolation isolator 1 installed on the foundation structure 10 The lower flange 3 is located on the upper surface of the main body concrete 40.

The seismic isolation isolator 1 is integrated by tightening the mounting bolts 31 of the support legs 30 (the configuration will be described later) so that the upper surface of the seismic isolation isolator support plate 20 is in close contact with the lower surface of the seismic isolation isolator 1 in advance, and further supported. By adjusting the protruding length of the leg length adjusting bolt 33 screwed to the lower end side of the leg 30, the installation height thereof is adjusted with high accuracy.

As shown in FIG. 1, inside the main body concrete 40 of the seismic isolation isolator foundation structure 10, a seismic isolation isolator support plate 20 supported by holding the level with four support legs 30 is placed on the upper part of the main body concrete 40. A plurality of sheer bars 41 are installed between the foundation slab 5 and the main body concrete 40 in order to be positioned and integrated with the foundation slab 5. In this embodiment, a deformed reinforcing bar (D19, length 800 mm as an example) is used as the shear bar 41. Further, in order to secure the strength and rigidity of the basic plate 5, two vertical and horizontal reinforcing bars 42 are provided.

As shown in FIG. 2A, the main structure of the seismic isolation isolator support plate 20 of the present embodiment is a half precast concrete having a substantially square shape having the same planar shape as the lower flange 3 of the seismic isolation isolator 1. It consists of version 21 (hereinafter referred to as PCa version 21). Support leg fixing holes 21a for fixing and holding the upper portion of the support leg 30 (FIG. 1) are formed near the four corners of the PCa plate 21. The upper portion of the support leg 30 is non-rotatably attached to the support leg fixing hole 21a.

The thickness of the PCa plate 21 is not equal as shown in FIGS. 2 (b-1) to (b-3), but a predetermined one-sided gradient as shown in FIG. 2 (b-1), for example. The bottom surface of the slope, as shown in Fig. (B-2), the flat cone-shaped bottom surface where the center part is the thickest, and as shown in the figure (b-3), the center part is the thickest. It has a flat convex curved bottom surface shape. By forming a predetermined gradient or the like on the lower surface in this way, when the main body concrete 40 is cast in the formwork 8 (FIG. 7 (c)), the concrete is formed along the gradient on the lower surface side of the PCa plate 21. Flows. Therefore, it is possible to prevent air or the like from remaining along the lower surface of the PCa plate 21, and the lower surface of the PCa plate 21 can be reliably filled with the main body concrete 40. When the gradient formed on the lower surface is sufficiently large and has horizontal resistance, a dowel effect can be expected to transmit the horizontal force acting on the seismic isolation isolator 1 to the main body concrete 40.

Reinforcing bars 23 are attached to the lower surface side of the PCa plate 21 at a predetermined pitch. The reinforcing bar 23 fulfills a dowel effect (shear resistance effect) between the seismic isolation isolator support plate 20 and the main body concrete 40 placed in the subsequent process. In the present embodiment, the reinforcing bars 23 as the dowel members are held by the continuous triangular lattice material 24 made of fine steel material and arranged at a predetermined pitch, as shown in FIGS. 1 and 2 (b-1). ing. FIG. 3 Each figure shows another holding means of the reinforcing bar 23. In FIG. 3A, a part of the corrugated reinforcing bar 26 held by the reinforcing bar 22 arranged in the PCa plate 21 is projected from the surface of the PCa plate 21, and the reinforcing bar 22 is held by a part of the corrugated reinforcing bar 26. It shows the holding structure. In FIG. 3B, a part of the oval ring bar 27 held by the reinforcing bar 22 arranged in the PCa plate 21 is projected from the surface of the PCa plate 21, and the reinforcing bar is partially formed on the oval ring bar 27. The holding structure which held 23 is shown. In FIG. 3C, the end hooks 28a of the hook bars 28 having various shapes held by the reinforcing bars 22 arranged in the PCa plate 21 are projected from the surface of the PCa plate 21, and the reinforcing bars 23 are formed on the end hooks 28a. Shows the state in which. In FIG. 3D, the tip of the dowel member 29 made of shaped steel partially embedded in the PCa plate 21 is projected from the surface of the PCa plate 21, and further, the through hole 29a of the tip of the dowel member 29 is formed. The structure which held the reinforcing bar 23 is shown. The dowel member 29 may be a piece member obtained by cutting and drilling a shaped steel of an appropriate size, and a plurality of dowel members 29 may be arranged so as to protrude from the PCa plate 21.

As shown in FIG. 4, the support leg 30 has a female screw 32a screwed with a mounting bolt 31 for fixing the lower flange 3 of the seismic isolation isolator 1 to the PCa plate 21 of the seismic isolation isolator support plate 20 on the inner peripheral surface. It is composed of an elongated cylindrical nut portion 32 formed and a leg length adjusting bolt 33 screwed into a female screw portion 32b on the lower side of the nut portion 32. In order to prevent the nut portion 32 of the present embodiment from rotating in the PCa plate 21, it is also preferable to provide a dowel 32c on the outer peripheral surface or to make the outer peripheral shape polygonal. By adjusting the amount of screwing of the leg length adjusting bolt 33 into the nut portion 32 to adjust the total length of the support leg 30, the installation height, horizontality, etc. of the seismic isolation isolator 1 can be appropriately adjusted. A flat disk-shaped grounding plate 33a is formed on the head of the leg length adjusting bolt 33, and by grounding the grounding plate 33a at a predetermined position on the foundation plate 5, the seismic isolation isolator 1 and the seismic isolation isolator support plate 20 are grounded. Can be stably and independently held only by the support leg 30.

FIG. 5 Each figure shows a joint reinforcing means 35 between the PCa plate 21 of the seismic isolation isolator support plate 20 and the lower flange 3 of the seismic isolation isolator 1. In FIG. 3A, the lower flange 3 of the seismic isolation isolator 1 and the PCa plate 21 are joined from the seismic isolation isolator 1 side by using mounting bolts 31, but in order to reinforce the joining state, PCa Tightening is performed by the reinforcing joint bolt 36 from the lower surface side of the plate 21. From the viewpoint of improving work efficiency, it is preferable that the reinforcing joint bolt 36 is fastened with the PCa plate 21 side as the upper surface by turning the top and bottom of the seismic isolation isolator 1 upside down before installing the seismic isolation isolator 1. It is preferable that the size and number of the reinforcing joint bolts 36 are appropriately set according to the standard of the seismic isolation isolator 1.

FIG. 3B shows a joint provided with a screwable fixing nut 37 on a male screw portion 32a formed on the outer peripheral surface of the support leg 30 in which the upper end portion is embedded in the PCa plate 21 of the seismic isolation isolator support plate 20. Reinforcing means 35 is shown. As shown in the figure, the fixing nut 37 screwed to the outer circumference of the support leg 30 is tightened toward the lower surface of the PCa plate 21 to form the PCa plate 21 and the lower flange 3 of the seismic isolation isolator 1. Can be brought into close contact with each other.

FIG. 6 shows a configuration example of a leg length fine adjustment bolt 38 as an auxiliary adjustment means for the leg length adjustment bolt 33 of the support leg 30 attached to the PCa plate 21 of the seismic isolation isolator support plate 20. The leg length fine adjustment bolt 38 shown in the figure is a bolt having a disc-shaped support plate 38a on the head screwed into the nut portion 39 embedded in the foundation plate 5, and the pitch is the leg length adjustment bolt 33. It is set smaller. Therefore, by using the leg length fine adjustment bolt 38, the installation height of the seismic isolation isolator 1 adjusted by the leg length adjustment bolt 33 on the support leg 30 side can be finely adjusted.

7 (a) to 7 (d) show each work procedure in the method of constructing the seismic isolation isolator basic structure 10 of the present invention.
The seismic isolation isolator support plate 20 is attached to the lower flange 3 of the seismic isolation isolator 1 using the mounting bolts 31, and an assembly in which both are integrated is manufactured (FIG. 7A). The production work of this assembly may be performed at the time of shipment from the factory of the seismic isolation isolator 1, or may be performed at the temporary storage place of the seismic isolation isolator 1 at the site. In this manufacturing work, it is preferable to use bolts 36 and nuts 37 as the joint reinforcing means 35 shown in each of FIGS. 5 as necessary. Next, the assembly is carried into the construction position of the seismic isolation isolator foundation structure 10, the leg length of the support leg 30 is adjusted, and the installation work of the assembly in which the position and height of the seismic isolation isolator 1 are accurately set is performed (FIG. 7 (b)). Reinforcing the reinforcing bars of the main body concrete 40, which is cast so as to include the assembly installed independently by the four support legs 30, and the assembling work of the formwork 8 of the foundation structure are performed (FIG. 7 (c)). It is preferable to drive the required number of shear bars 41 into a predetermined position of the basic plate 5 at the timing of constructing the basic plate 5. The main body concrete 40 is placed in the formwork 8 to a height at which the seismic isolation isolator support plate 20 is completely buried in the concrete, and the frame is removed after a predetermined curing period to complete the foundation structure (FIG. 7 (d)). )).

FIG. 8 shows another embodiment in which the seismic isolation isolator foundation structure 10 is applied to the sliding bearing 50. The sliding bearing 50 illustrated in FIG. 8 includes a sliding plate 51 made of a smooth stainless steel plate and a laminated rubber portion 52 slidably placed on the sliding plate 51. A sliding surface 53 made of fluororesin is formed on the lower surface of the laminated rubber portion 52. In the sliding bearing 50 having such a configuration, only the laminated rubber portion 52 is deformed during a small-amplitude earthquake, and when the amplitude is large, the laminated rubber portion 52 slides smoothly on the sliding plate 51, as in the case of a large earthquake. It can follow a big shake. Therefore, the sliding plate 51 has a large area, and the seismic isolation isolator support plate 20 needs to be constructed so as not to be deformed by a vertical load acting on the large area. Therefore, in this embodiment, as shown in FIG. 8, a slide plate having a large area is supported by a plurality of small seismic isolation isolator support plates 20. Thereby, the size and weight of each seismic isolation isolator support plate 20 can be reduced.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope shown in each claim. That is, an embodiment obtained by combining technical means appropriately modified within the scope of the claims is also included in the technical scope of the present invention.

1 Seismic isolation isolator 2 Laminated rubber part 3 Lower flange 5 Foundation plate 10 Seismic isolation isolator foundation structure 20 Seismic isolation isolator support plate 21 Precast concrete plate (PCa version)
30 Support leg 31 Mounting bolt 32 Nut part 33 Leg length adjustment bolt 40 Main body concrete

Claims (5)

A seismic isolation isolator support plate made of precast concrete, which is joined to the lower flange of the seismic isolation isolator and the dowel members are arranged so as to protrude from the lower surface.
The upper part is fixedly held by the seismic isolation isolator support plate, the seismic isolation isolator has a fastening portion for joining the seismic isolation isolator on the upper end side, and a leg length adjusting portion is provided on the lower end side. Support legs and
It is a seismic isolation isolator foundation structure equipped with
A seismic isolation isolator foundation structure characterized in that a main body concrete portion for supporting the seismic isolation isolator is formed so as to include the seismic isolation isolator support plate and the support legs. The seismic isolation isolator basic structure according to claim 1, wherein the seismic isolation isolator support plate has a slope formed on the lower surface thereof. The seismic isolation isolator basic structure according to claim 1, wherein the dowel member is a reinforcing bar held and arranged so as to protrude from the lower surface, and a method for constructing the same. The support leg is made of a long nut, a fixing bolt for fixing the seismic isolation isolator to the seismic isolation isolator support plate is screwed into the upper female screw portion, and the seismic isolation isolator support plate is screwed to the lower end female screw portion. The seismic isolation isolator basic structure according to claim 1, wherein a leg length adjusting bolt that is self-supporting on the basic plate is screwed. A precast concrete seismic isolation isolator support plate, in which the dowel members are arranged so as to protrude from the lower surface, is joined to the lower flange of the seismic isolation isolator.
The seismic isolation isolator is held independently at a predetermined position on the foundation plate by adjusting the installation height by the leg length adjusting portion of the support leg whose upper part is fixedly held on the seismic isolation isolator support plate, and the seismic isolation isolator support plate and the seismic isolation isolator support plate are used. A method for constructing a seismic isolation isolator foundation structure, which comprises placing a main body concrete that supports the seismic isolation isolator so as to include the support legs.

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