JP7692286B2 - Seismic isolation device installation structure - Google Patents

Description

The present invention relates to a seismic isolation device installation structure.

A structure for installing seismic isolation devices in buildings is known (see, for example, Patent Document 1).

JP 2016-153571 A

In the case of mid-story seismic isolation in steel-framed structures, the columns supporting the seismic isolation device are often made of CFT (Concrete Filled Steel Tube) structures.
However, if this seismic isolation device includes a sliding bearing, a large-area sliding plate is required to allow the bearing to slide, and the joint on the side receiving the bearing becomes larger. Accordingly, the cross section of the column supporting the seismic isolation device from below also becomes larger, and the steel pipe of the column becomes a large-section build box (a welded four-sided box made by welding four thick plates), which has a large impact on costs. Therefore, it was difficult to adopt a sliding bearing for mid-story seismic isolation in which the columns supporting the seismic isolation device are CFT.

For this reason, it is possible to use steel reinforced concrete construction (SRC) for the columns that support the seismic isolation device. However, if the columns are made of SRC, the steel frame must be erected, followed by the reinforcing bars, installation of formwork, pouring of concrete, and removal of formwork, and once the columns are complete, the seismic isolation device must be installed, and then the steel frame above the seismic isolation device must be erected, which creates the problem of longer construction times.

The present invention takes the above facts into consideration and aims to provide a seismic isolation device installation structure that can shorten the construction period and allows the seismic isolation device to be installed early, so that the steel frame above the seismic isolation device can be erected without waiting for the reinforcing bars below or the pouring of concrete.

The seismic isolation device installation structure described in the first aspect comprises a column made of steel reinforced concrete, a steel pipe connection member joined to the upper part of the steel material of the column and filled with concrete inside, and a seismic isolation device installed on a base plate provided on the upper part of the steel pipe connection member, and a connecting bar whose upper part is embedded in the concrete of the steel pipe connection member and whose lower part protrudes from the underside of the steel pipe connection member is connected to the main column reinforcement of the column.

In the seismic isolation device installation structure described in the first aspect , the steel pipe connection member in which the seismic isolation device is installed is of so-called CFT construction, and the columns supporting the steel pipe connection member are of steel-reinforced concrete construction.

Therefore, in the seismic isolation device installation structure described in the first aspect , a steel pipe connection member is joined to the top of a steel material that is part of the components of a steel reinforced concrete column, and concrete is filled inside the steel pipe connection member and allowed to harden, allowing a seismic isolation device to be installed on the base plate provided on the top of the steel pipe connection member.

As a result, the construction period can be shortened because the erection of the steel frame above the seismic isolation device and the work of arranging the reinforcement for the steel-reinforced concrete columns and pouring the concrete formwork can be carried out in parallel.

In addition, by connecting the connecting bars protruding from the underside of the steel pipe joint member to the main reinforcement of the column, the axial force can be reliably transmitted from the joint to the column even if the two structures are different, such as the steel pipe joint member being made of CFT and the column being made of SRC.

The invention described in a second aspect is the seismic isolation device installation structure described in the first aspect , wherein the seismic isolation device includes a laminated rubber and a sliding bearing provided between the laminated rubber and the base plate.

In the seismic isolation device installation structure described in the second aspect , the laminated rubber functions when subjected to a small earthquake force, and when subjected to a large earthquake force, the sliding bearings cause the laminated rubber to slide, thereby reducing the swaying of the building.

The invention described in the third aspect is the seismic isolation device installation structure described in the second aspect , in which the cross-sectional area of the steel pipe joint member at the upper part where the base plate is attached is larger than the cross-sectional area of the lower part where the steel pipe joint member is joined to the steel material of the column.

The invention described in the third aspect , in the seismic isolation device installation structure described in the second aspect , eliminates the need to increase the cross-sectional area of the pillars to match the amount of slippage of the laminated rubber, i.e., makes it possible to make the pillars thinner.

As described above, the seismic isolation device installation structure of the present invention has the excellent effect of shortening the construction period and allowing the seismic isolation device to be installed early, so that the steel frame above the seismic isolation device can be erected without waiting for the reinforcing bars below or the pouring of concrete.

1 is an elevational view showing a main portion of a seismic isolation building to which a seismic isolation device installation structure according to one embodiment of the present invention is applied. 1A is a plan view showing a base plate of a steel pipe connection member, FIG. 1B is a plan view showing a partition plate of the steel pipe connection member, and FIG. 1C is a plan view showing a bottom plate of the steel pipe connection member. FIG. 2 is a cross-sectional view showing a seismic isolation device. FIG. 13 is an elevation view showing a steel frame with a box joined to the top. FIG. 13 is an elevational view of the box with the connecting bars attached. FIG. 1 is a cross-sectional view showing a box filled with concrete. FIG. 1 is a cross-sectional view of a box filled with concrete and grout. FIG. 2 is an elevational view showing a box equipped with a seismic isolation device. This is an elevational view showing the foundation with reinforcement and poured concrete, and the steel frame with reinforcement. FIG. 2 is an elevational view showing the state in which concrete has been filled into the formwork. FIG. 1 is an elevation view showing a formwork with spaces filled with grout.

1 to 11, a seismic isolation structure 12 to which a seismic isolation device installation structure 10 according to one embodiment of the present invention is applied will be described.
FIG. 1 shows the first basement floor of a seismic isolation structure 12 to which a seismic isolation device installation structure 10 according to this embodiment is applied.
The seismic isolation structure 12 includes a foundation beam 14 made of reinforced concrete, and a plurality of SRC columns 16 erected on the foundation beam 14. The seismic isolation structure of this embodiment is a so-called mid-story seismic isolation building in which a seismic isolation device 60 is provided on the intermediate floor of the building.

A CFT steel pipe joint member 18 is provided on the top of the column 16. A beam 20 is attached to the side of this steel pipe joint member 18, and a seismic isolation device 60 (described later) is installed on the top of the steel pipe joint member 18.

In addition, a concrete pile 22 is buried in the ground G directly below the pillar 16.

(Column structure)
The column 16 has steel frame materials 26, column main reinforcement bars 28, and hoop reinforcement bars 30 embedded in concrete 24. As the steel frame materials 26 in this embodiment, cross H-beams are used as an example, but other steel frame materials can also be used.

(Steel pipe connection components)
The steel pipe connection member 18 includes a steel box 32 having an inverted trapezoidal shape in side view, the horizontal cross-sectional area of which decreases downward.
The box 32 has a tubular portion formed by four lower plates 34 and four upper plates 36, and the upper opening of the tubular portion is blocked by a base plate 38 which serves as the upper part of the steel pipe connection member 18, and the lower side of the tubular portion is blocked by a bottom plate 40 which serves as the lower part of the steel pipe connection member 18.

The tubular portion is formed so that its axial direction is vertical, and a partition plate 42 is provided in the middle in the vertical direction. The lower plate 34, upper plate 36, base plate 38, bottom plate 40, and partition plate 42 are all formed from steel plates.

As shown in FIG. 2(A), the base plate 38 is formed in a rectangular shape in a plan view, with a circular concrete pouring hole 44 formed in the center and four rectangular concrete pouring holes 46 formed around the concrete pouring hole 44.

This base plate 38 is formed larger than the bottom plate 40. The size of the base plate 38 is determined according to the size of the sliding plate 70 of the seismic isolation device 60 described below, and the size of the bottom plate 40 is determined according to the thickness of the column 16.

As shown in FIG. 2B, the partition plate 42 is formed in a rectangular shape, and a concrete pouring hole 48 similar to the concrete pouring hole 46 formed in the base plate 38 is formed directly below the concrete pouring hole 46 as shown in FIG. 1.

As shown in Figures 1 and 2(C), the bottom plate 40 has multiple (four in this embodiment) connecting rebar through holes 50 formed directly below the concrete pouring holes 48 of the partition plate 42. The connecting rebar through holes 50 are penetrated by the connecting rebars 52 inserted through the concrete pouring holes 46 and the concrete pouring holes 48. The connecting rebar through holes 50 are formed to have a slightly larger diameter than the connecting rebars 52.

The connecting rebar 52 passes through the connecting rebar through hole 50 in the vertical direction, with its upper part positioned inside the box 32 and formed into a hook shape.

The lower end of the connecting steel bar 52 protruding below the bottom plate 40 is joined to the upper end of the main column bar 28 of the column 16 using a mechanical joint 54.

The inside of the box 32 is filled with concrete 58 and grout 76 without any gaps.

(earthquake-proof device)
A seismic isolation device 60 is mounted on the base plate 38 of the box 32 .
3, the seismic isolation device 60 of this embodiment includes a sliding bearing 62 and a cylindrical laminated rubber 64, and the laminated rubber 64 and the sliding bearing 62 are arranged in series in the vertical direction. The laminated rubber 64 is formed by alternately laminating thin reinforcing steel plates 64A and rubber layers 64B.

A disk-shaped steel flange 66 is provided at the upper end of the laminated rubber 64, and this flange 66 is fixed to an upper structure 68 provided on the upper side of the laminated rubber 64. The shape of the laminated rubber 64 may be a shape other than a cylinder, for example, a square column.

The sliding bearing 62 is composed of a sliding plate 70 provided on the steel pipe connection member side and a disk-shaped sliding member 72 provided on the rubber body side. The planar shape of the sliding plate 70 is, for example, a square.

The sliding plate 70 is fixed to the upper surface of the base plate 38 of the steel pipe joint member 18. The sliding member 72 is fixed to the thick reinforcing steel plate 64C of the laminated rubber 64 and is in sliding contact with the sliding plate 70. The planar shapes of the sliding plate 70 and the sliding member 72 may be other shapes.

(superstructure)
An upper structure 68 is supported on the upper part of the laminated rubber 64. The upper structure 68 is, for example, a building having a plurality of interior columns (not shown) erected on the seismic isolation device 60, and beams (not shown) installed between the base parts of adjacent interior columns. The base parts of the interior columns form a column-beam joint, and the ends of the beams are joined to the base parts.

(Construction procedure)
Next, a construction procedure for the seismic isolation structure 12 of this embodiment will be described.

(1) Steel Frame Construction of Columns As shown in Fig. 4, concrete 78 that will form the base for the lower part of the foundation beam 14 is poured on the ground G, and then steel frame materials 26 are erected on the upper side of the concrete piles 22. After that, a box 32 is attached to the top of the steel frame materials 26, and a beam 20 is attached to the side of the box 32. Note that the reinforcing bars inside the concrete 78 are not shown in Fig. 4 and other drawings.

(2) Installation of Connecting Reinforcement Bars Next, as shown in Fig. 5, connecting reinforcing bars 52 are dropped from above the box 32 into connecting reinforcing bar through holes 50 (see Fig. 2(C)) of the bottom plate 40, so that the lower ends of the connecting reinforcing bars 52 protrude downward from the bottom plate 40. The connecting reinforcing bars 52 are temporarily held in place in the box 32 using a jig (not shown).

(3) Pouring Concrete As shown in Fig. 6, concrete 58 is poured into the box 32 through the concrete pouring hole 44 or the concrete pouring hole 46 of the box 32. In this embodiment, the concrete 58 is poured so that a gap-like space S1 is formed between the upper surface of the concrete 58 and the lower surface of the base plate 38. Note that it is preferable to fill the gap between the connection rebar through hole 50 and the connection rebar 52 with a filler or the like in advance so that the concrete 58 does not leak out from the gap.

(4) Filling with grout After the concrete 58 has hardened, as shown in Fig. 7, a non-shrink grout 76 is filled in the space S1 formed between the upper surface of the concrete 58 and the lower surface of the base plate 38, and the grout 76 is brought into contact with the lower surface of the base plate 38. Once the grout 76 has hardened, the steel pipe connection member 18 for CFT construction is completed.

(5) Installation of the Seismic Isolation Device After the grout agent 76 has hardened, the seismic isolation device 60 is mounted on the base plate 38 as shown in Fig. 8, and the sliding plate 70 is fixed to the base plate 38. The upper surface of the base plate 38 may be ground with a grinder.
After the seismic isolation device 60 is installed, it is possible to erect the steel frame of the upper structure 68 on top of the seismic isolation device 60.

(6) Connection of column main reinforcement and connecting rebars, reinforcing bar arrangement for foundation beams, reinforcing bar arrangement for basement columns, and pouring concrete for foundation beams After the installation of the seismic isolation device 60 is completed, as shown in Fig. 9, the column main reinforcement 28 is arranged along the steel frame 26, and the upper end portion of the column main reinforcement 28 is connected to the lower end portion of the connecting rebar 52 of the steel pipe connection member 18 with a mechanical joint 54. Then, the hoops 30 are arranged around the steel frame 26, and the reinforcing bars 14A of the foundation beam 14 are arranged on top of the concrete 78, and concrete 14B is poured.

(7) Pouring Concrete for Columns After the concrete 14B of the foundation beam 14 has hardened, as shown in Fig. 10, a formwork 80 is provided around the steel frame 26, and concrete 24 is pressed into the formwork through holes (not shown) provided in the formwork 80. In this embodiment, the concrete 24 is pressed in so that a gap-like space S2 is formed between the concrete 24 and the bottom plate 40 of the steel pipe connection member 18.

(8) Filling with Grout After the concrete 24 has hardened, as shown in Fig. 11, a non-shrink grout 82 is filled in the space S2 formed between the upper surface of the concrete 24 and the lower surface of the bottom plate 40, and the grout 82 is brought into contact with the lower surface of the bottom plate 40. Note that the grout 82 is filled through filling holes (not shown) formed in the side surface of the formwork 80, for example.

(9) Removal of the Column Formwork After the grout 82 has hardened, the formwork 80 is removed and the SRC column 16 is completed (see FIG. 1).

(effect)
The seismic isolation structure 12 of this embodiment is characterized in that the steel pipe joint member 18 is made of CFT and the column 16 is made of SRC. Therefore, the box 32 is joined to the upper part of the steel frame 26 before the column 16 is completed, concrete 58 is poured inside the box 32, and the seismic isolation device 60 can be installed after filling with grout agent 76 and hardening. Therefore, the seismic isolation device 60 can be installed early and the steel frame above the seismic isolation device 60 can be erected without waiting for the reinforcing bar arrangement of the lower column 16 and the pouring of concrete. In addition, the erection of the steel frame above the seismic isolation device 60 can be carried out in parallel with the reinforcing bar arrangement work and the pouring of concrete formwork for the column 16 of steel reinforced concrete structure, thereby shortening the construction period.

Since CFT construction requires only filling steel pipes with concrete and allowing it to harden, it is easier to construct on-site than SRC construction, which requires arranging reinforcement, setting formwork, filling with concrete, and then removing the formwork.

In the seismic isolation structure 12 of this embodiment, the cross-sectional area of the pillars 16 is not determined according to the size of the sliding plate 70 of the bearing-equipped seismic isolation device 60, so there is no need to make the cross-sectional area of the pillars 16 larger than necessary, and the impact on costs can also be reduced.

In other words, the pillar 16 only needs to have the minimum necessary cross-sectional area (thickness) to support the load above, and can be made thinner than when the cross-sectional area of the pillar 16 is determined according to the size of the sliding plate 70.

Furthermore, in the seismic isolation device installation structure 10 of this embodiment, the connecting rebar 52 protruding from the underside of the steel pipe connection member 18 is connected to the column main reinforcement 28 of the column 16, so that even if the two structures are different, such as the steel pipe connection member 18 being made of CFT and the column 16 being made of SRC, the axial force can be reliably transmitted from the steel pipe connection member 18 to the column 16.

[Other embodiments]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and it goes without saying that the present invention can be implemented in various modified forms without departing from the spirit and scope of the present invention.

In the above embodiment, the column main reinforcement 28 and the connecting reinforcement 52 are connected by a mechanical joint 54, but the present invention is not limited to this, and the column main reinforcement 28 and the connecting reinforcement 52 may be joined by welding.

In this embodiment, the seismic isolation device 60 includes a sliding bearing 62 and a laminated rubber 64, but the present invention is not limited to this, and the seismic isolation device 60 may be of another type.

In the above embodiment, concrete 24 is pressed into the formwork 80 so that a gap-like space S2 is formed between the bottom plate 40 of the steel pipe joint member 18 and the concrete 24 is then filled into the space S2 with grout 82. However, concrete 24 may also be pressed into the formwork 80 so that the space S2 is not formed.

In the above embodiment, concrete 58 is poured into the box 32 so that a gap-like space S1 is formed between the steel pipe joint member 18 and the base plate 38, and then the space S1 is filled with grout 76, but concrete 58 may be poured into the box 32 so that the space S1 is not formed.

REFERENCE SIGNS LIST 10 Seismic isolation device installation structure 16 Column 18 Steel pipe connection member 26 Steel frame material 28 Column main reinforcement 38 Base plate 52 Connection reinforcing bar 54 Mechanical joint 58 Concrete of steel pipe connection member 60 Seismic isolation device 62 Sliding bearing 64 Multilayer rubber

Claims (3)

Steel reinforced concrete columns and
A steel pipe joint member joined to the upper part of the steel frame of the column and filled with concrete;
a seismic isolation device installed on a base plate provided on an upper portion of the steel pipe connection member;
Equipped with
The upper part of the connection rebar is embedded in the concrete of the steel pipe connection member and the lower part of the connection rebar protruding from the lower surface of the steel pipe connection member is connected to the column main reinforcement of the column,
A concrete pouring hole is formed in the base plate so that the seismic isolation device can be installed on the base plate with the upper part of the erected steel frame buried in the concrete filled inside the steel pipe connection member, and the lower part of the steel pipe connection member is closed with a bottom plate.
Seismic isolation device installation structure. The seismic isolation device includes a laminated rubber and a sliding bearing provided between the laminated rubber and the base plate.
The seismic isolation device installation structure according to claim 1 . The cross-sectional area of the upper part of the steel pipe connection member to which the base plate is attached is larger than the cross-sectional area of the lower part connected to the steel frame of the column.
The seismic isolation device installation structure according to claim 2.