JP6721979B2 - Joint structure between pile head and seismic isolation device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a joint structure of a seismic isolation device provided between a pile of a building and a structure, and relates to a joint structure of a pile head and a seismic isolation device using a joint portion of a connecting beam and a pile head as a precast member. Is.

BACKGROUND ART Conventionally, seismic isolation devices used for building structures have been installed for each of the piles provided on the ground, and seismic isolation devices have been used to suppress seismic force and prevent structural damage. However, in order to install the seismic isolation device, the amount of price cut down into the ground increases, and the construction becomes complicated as compared with other buildings, resulting in an increase in cost.

On the other hand, by adopting, for example, a structure in which the seismic isolation device is directly mounted on the pile head as a joint structure of the seismic isolation device using the pile head, the rotation angle of the pile head is reduced as a rigid structure as much as possible. I was doing. However, the rigid structure described above tends to increase the degree of fixation of the joint portion and increase the bending stress near the pile head.

Therefore, by joining a precast member that is a combination of a PC ring with a plurality of anchoring bars protruding and a PCa member that is placed on top of the PC ring by inserting a plurality of anchoring bars to the head of the pile, A structure has been proposed that reduces bending stress in the vicinity (for example, refer to Patent Document 1).

Japanese Patent Application No. 2008-231799

However, in the above-described conventional structure, since the number of members is large and the joint portions between the members are scattered at a plurality of points, there is a possibility that seismic force or other external force is transmitted and damage is likely to occur. Further, the cost of material procurement and construction increases according to the number of members.

In particular, in order to mount the PC ring so as to surround the pile head, a spacer is mounted between the inner peripheral wall of the PC ring and the outer peripheral wall of the pile head, and the level is adjusted on the lower surface of the PC ring. Since the level adjustment insert of is required, intricate construction is inevitable.

It is an object of the present invention, while suppressing the number of materials required for the placement of the precast reinforced concrete pile caps and pre-cast reinforced concrete pile caps, pile head and seismic isolation apparatus implementing a suitable state as seismic isolation It is to provide a joint structure with.

In order to solve the above problems, the joint structure between the pile head and the seismic isolation device according to the present invention is a structure in which the pile head and the seismic isolation device are joined via a precast reinforced concrete pile cap , On the upper surface of the precast reinforced concrete pile cap , an anchor plate for joining with the seismic isolation device is integrally provided, and on the side surface of the precast reinforced concrete pile cap , a cotter for joining with a connecting beam. Is formed in a concave shape, the bottom surface of the precast reinforced concrete pile cap is formed with a recess for covering the upper end of the pile head, between the pile head and the precast reinforced concrete pile cap. Is characterized in that a non-shrinkage mortar is further interposed.

Further, it is desirable that a through hole for injecting the non-shrink mortar be formed so as to extend from a predetermined position on the upper surface or the side surface of the precast reinforced concrete pile cap to the recess.

Bonding structure with another pile head and the vibration isolating apparatus according to the present invention is a structure in which the pile head and the seismic isolation device is bonded via the precast reinforced concrete pile cap, the upper surface of the precast reinforced concrete pile cap Anchor plate for joining with the seismic isolation device is integrally provided, and on the side surface of the precast reinforced concrete pile cap , a cotter for joining with the connecting beam is formed in a concave shape, Between the pile head and the precast reinforced concrete pile cap , further non-shrink mortar is interposed, the upper end projects from the anchor plate, and the lower end is fixed inside the pile head. A tension member tightly connects the precast reinforced concrete pile cap and the pile head.

Further, it is preferable that the tension member is a steel wire or a reinforcing bar provided at the time of forming the pile head.

Further, the precast reinforced concrete pile cap, it is desirable to cast-in-place reinforced concrete pile cap in a conventional method can be replaced.

The joint structure of the pile head and the seismic isolation device according to the present invention has an anchor plate on the upper surface of the precast reinforced concrete pile cap , a cotter on the side surface, and a recess on the bottom surface, thereby improving the construction efficiency and precasting. Semi-rigid joint between reinforced concrete pile cap and pile head is realized. That is, since the anchor plate is integrally provided, the seismic isolation device and the precast reinforced concrete pile cap can be easily joined. Moreover, since the cotter is formed in a concave shape, the shear stress of the precast reinforced concrete pile cap is increased. Furthermore, the non-shrinkable mortar intervenes in the gap with the precast reinforced concrete pile cap that can be formed by the recess covering the upper end of the pile head, realizing a semi-rigid joint between the precast reinforced concrete pile cap and the pile head. It can also be expected to ease the rotation angle of the pile head.

Another pile head structure and seismic isolation device according to the present invention has an anchor plate on the upper surface of a precast reinforced concrete pile cap and a cotter on the side surface, and a tension member is a precast reinforced concrete pile cap and a pile head. By tightly connecting the parts with each other, the construction efficiency is improved, and the degree of joint between the precast reinforced concrete pile cap and the pile head is higher than that of the semi-rigid joint. That is, since the anchor plate is integrally provided, the seismic isolation device and the precast reinforced concrete pile cap can be easily joined. Moreover, since the cotter is formed in a concave shape, the shear stress of the precast reinforced concrete pile cap is increased. Furthermore, the non-shrinkable mortar is interposed between the precast reinforced concrete pile cap and the pile head, and the tension member is used to bond the precast reinforced concrete pile cap to the pile head, resulting in a better degree of bonding than semi-rigid joints. Achieve to a high degree.

It is a perspective view showing an example of a seismic isolation structure provided with one embodiment of the present invention. It is a side sectional view showing a part of the above-mentioned seismic isolation structure. It is an expanded side sectional view which shows a part of said seismic isolation structure. It is a side sectional view showing a part of seismic isolation structure provided with another embodiment of the present invention.

Hereinafter, a joint structure between a pile head and a base isolation device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

First, the outline of the joint structure between the pile head and the seismic isolation device will be described with reference to FIG. FIG. 1 shows an outline of a part of a seismic isolation structure in which a structure is supported on a pile head of a pile formed at a predetermined location via a seismic isolation device.

The joint structure between the pile head and the seismic isolation device according to the embodiment of the present invention is a structure in which the pile head 1 and the seismic isolation device 2 are joined via a precast reinforced concrete pile cap 3.
An anchor plate 31 for joining to the seismic isolation device is integrally provided on the upper surface of the precast reinforced concrete pile cap, and the side surface of the precast reinforced concrete pile cap is joined to the connecting beam 4. The cotter 32 is formed in a concave shape, and a recess 33 for covering the upper end of the pile head is formed on the bottom surface of the precast reinforced concrete pile cap . The pile head and the precast reinforced concrete pile are formed. A non-shrink mortar 34 may be interposed between the cap and the cap .

Further, a through hole (not numbered) for injecting the non-shrink mortar 34 may be provided from a predetermined position on the upper surface or the side surface of the precast reinforced concrete pile cap 3 to the recess 33.

Next, the details of the joint structure between the pile head and the seismic isolation device will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a structure below the seismic isolation device.

As shown in FIG. 2, the pile head 1 is a tip portion of a pile of a building provided on the ground, and may be a tip portion after the upper side of the pile is initially cut. The diameter of the pile head 1 may be the same as or larger than the diameter of the pile. The area of the upper end of the pile head 1 is preferably large enough to install the seismic isolation device 2, and may be the same as or larger than the bottom area of the seismic isolation device.
The pile type may be cast-in-place pile, concrete pile or steel pipe pile. The upper end of the pile head 1 is not limited to a flat shape, but may be an uneven shape. The pile head 1 and the pile may be integrally formed by a predetermined construction method.

The seismic isolation device 2 is composed of a cylindrical seismic isolation member (not numbered) in which predetermined rubber plates and hard plates are laminated, and flange plates (not numbered) provided on the upper and lower surfaces of this seismic isolation member. It may be done. The lower part of the seismic isolation device 2 may be fixed to the precast reinforced concrete pile cap 3, and the upper part may be fixed to the structure B, respectively.
The material and size of the seismic isolation device 2 are not limited, and may be selectable according to the scale of the building and the degree of seismic isolation.

The precast reinforced concrete pile cap 3 has an anchor plate 31 integrally provided on the upper surface thereof for joining with a flange plate of the seismic isolation device 2 through a bolt hole and a predetermined bolt, and a connecting beam 4 on this side surface. The cotter 32 has a concave shape for connection, and the bottom surface of the cotter 32 may have a recess 33 for covering from the upper end of the pile head 1 to a predetermined height on the side surface.
The top area, the bottom area, and the dimensions of each part of the precast reinforced concrete pile cap 3 are not limited, and at least the bottom area is preferably larger than the area of the upper end of the pile head 1. The material forming the precast reinforced concrete pile cap 3 is not limited to reinforced concrete, and any material having rigidity such as steel may be used. The shape of the precast reinforced concrete pile cap 3 is not limited to a cylindrical shape and may be a columnar shape.

The anchor plate 31 may be a plate-like member that is fixed by driving a predetermined bolt on the upper surface of the precast reinforced concrete pile cap 3.
The area and dimensions of each part of the anchor plate 31 are not limited, and are preferably larger than the diameter of the flange plate of the seismic isolation device 2. The precast reinforced concrete pile cap 3 and the anchor plate 31 may be provided in a non-detachable state with a predetermined adhesive or in a detachable state with a joining member such as a predetermined screw.

The cotter 32 is for increasing the shear stress of the precast reinforced concrete pile cap 3, and may be a rectangular recess provided on the upper side of the side surface of the precast reinforced concrete pile cap .
The shape of the cotter 32 is not limited to the rectangular shape and may be a hemispherical shape. Further, the shape, size and position of the cotter 32 are not limited, and it is desirable that the precast reinforced concrete pile cap 3 maximizes the shear stress effect. The cotter 32 may be provided by molding when the precast reinforced concrete pile cap 3 is molded, or may be dug after the molding.

The precast reinforced concrete pile cap 3 and the connecting beam 4 may be joined together by composite rebars 5a and/or 5b, 5b. The composite reinforcing bars 5a, 5b and 5b may be provided orthogonally to the joint surface between the precast reinforced concrete pile cap 3 and the connecting beam 4. The composite rebar 5a may be provided as a pin joint through the center of the cotter 32 in a sectional view. The composite rebars 5b, 5b may be provided above and below the cotter 32 in a sectional view as a fixed joint.
The composite reinforcing bars 5a and/or 5b, 5b may be inserted in advance before construction of the precast reinforced concrete pile cap 3 or may be connected by a relay joint or the like after construction. The precast reinforced concrete pile cap 3 and the connecting beam 4 may be joined together to form a pressure board.

The recess 33 may cover the pile head 1 from the upper end to a predetermined height on the side surface and semi-rigidly join the pile head and the precast reinforced concrete pile cap 3.
The concave portion 33 may be provided by molding when the precast reinforced concrete pile cap 3 is molded, or may be dug after the molding.

Here, the details of the joint structure between the upper end of the pile head and the recess of the precast reinforced concrete pile cap will be described with reference to FIG. FIG. 3 is an enlarged view of a part of FIG. 2. FIG. 3(A) shows a state before injection of non-shrink mortar, and FIG. 3(B) shows a state after injection of non-shrink mortar.

As shown in FIG. 3(A), if there is a protrusion on the upper end 11 of the pile head 1, a gap Sa may occur between this upper end and the upper surface 33a of the recess 33 of the precast reinforced concrete pile cap 3. In this case, non-shrink mortar may be injected from a predetermined position on the side surface of the precast reinforced concrete pile cap 3 through a through hole 35 provided over the upper surface 33a of the recess 33. Furthermore, the non-shrinkage mortar may flow from the gap Sa to the gap Sb between the inner side surface 33b of the recess 33 and the side surface 12 of the pile head 1.
Then, as shown in FIG. 3(B), the solidified non-shrink mortar 34 includes the upper end 11 and the side surface 12 of the pile head 1, the upper surface 33a and the inner side surface 33b of the recess 33 of the precast reinforced concrete pile cap 3, and the discarded. The smooth surface of the concrete C may be joined to each other. In this case, the pile head 1 may be semi-rigidly joined to the precast reinforced concrete pile cap 3.
The non-shrink mortar 34 may be directly applied to the upper end 11 of the pile head 1 and/or the upper surface 33a of the recess 33 of the precast reinforced concrete pile cap 3. The material is not limited to the non-shrink mortar 34, and any material may be used as long as it has high fluidity at the time of injection and has a predetermined rigidity at the time of joining. The through-hole 35 may be provided by molding at the time of molding the precast reinforced concrete pile cap 3, or may be dug after the molding.

Next, an example of a construction method of the joint structure between the pile head and the seismic isolation device shown in FIGS. 2 and 3 will be described.

First, the area around the pile of the building provided on the ground is excavated to expose the tip. Then, the exposed tip portion is cut by a predetermined method, and the remaining tip portion is used as the pile head 1. After that, the concrete C is thrown out from the periphery of the pile head 1 to the ground.

Next, the pile head 1 is placed so that the upper surface 11a of the recess 33 of the precast reinforced concrete pile cap 3 contacts the upper end 11 of the pile head 1. At this time, the pile head 1 and the precast reinforced concrete pile cap 3 are not joined and are in a removable state. Then, the non-contraction mortar 34 that has flowed into the gap Sa and the gap Sb from the through hole 35 is solidified in the predetermined time. As a result, the upper end 11 and the side surface 12 of the pile head 1, the upper surface 33a and the inner side surface 33b of the recess 33 of the precast reinforced concrete pile cap 3, and the smooth surface of the discarded concrete C are semi-rigid bonded via the non-shrink mortar 34. It becomes a state. Then, the anchor plate 31 of the precast reinforced concrete pile cap 3 and the lower flange plate of the seismic isolation device 2 are connected by bolts.

After that, the connecting beam 4 is driven so that the composite rebar 5a passing through the center of the cotter 32 and/or the composite rebar 5b, 5b passing through the top and bottom of this cotter are installed, and the upper flange plate of the seismic isolation device 2 is installed. And structure B with bolts.

As described above, the joint structure between the pile head 1 and the seismic isolation device 2 according to the embodiment of the present invention has the anchor plate 31, the cotter 32 on the side surface, and the recess 33 on the bottom surface of the precast reinforced concrete pile cap 3, respectively. By being provided, the construction efficiency is improved, and a semi-rigid joint between the pile head and the precast reinforced concrete pile cap is realized. That is, since the anchor plate 31 is integrally provided, the seismic isolation device 2 and the precast reinforced concrete pile cap 3 can be easily joined. Moreover, since the cotter 32 is formed in a concave shape, the shear stress of the precast reinforced concrete pile cap 3 is increased. Further, the recess 33 covers the upper end of the pile head 1 and the non-shrink mortar 34 is present in the gap between the recess and the pile head, so that the precast reinforced concrete pile cap and the pile head are Semi-rigid connection is realized, and relaxation of the pile head rotation angle can be expected.

Next, a joint structure between a pile head and a base isolation device according to another embodiment of the present invention will be described with reference to FIG. FIG. 4(A) shows a part of the structure lower than the seismic isolation device in a side view, and FIG. 4(B) shows a part of the structure lower than the seismic isolation device in a top view. is there.
It should be noted that, for ease of reference, etc., the same materials as the base materials, parts or parts shown in FIGS. In addition, description of the equivalents to the base material, parts, or portions described with reference to FIGS. 1 to 3 will be omitted.

As shown in FIG. 4(A) and FIG. 4(B), the joint structure between the pile head and the seismic isolation device according to another embodiment of the present invention includes a pile head 101 and a seismic isolation device (not numbered). Is a structure that is joined via a precast reinforced concrete pile cap 103, and an anchor plate 131 for joining with the seismic isolation device is integrally provided on the upper surface of the precast reinforced concrete pile cap. On the side of the precast reinforced concrete pile cap , a cotter (not numbered) for joining to the connecting beam (not numbered) is formed in a concave shape, and between this pile head and the precast reinforced concrete pile cap. Is a non-shrink mortar (not shown), the upper end 161a projects from the anchor plate, and the lower end 161b is fixed inside the pile head. The pile cap may be tightly connected to the head of the pile.

The diameter of the pile head 101 may be larger than the diameter of the pile.

The precast reinforced concrete pile cap 103 may have a rectangular shape, and the bottom surface of the precast reinforced concrete pile cap may have a flat shape.

The anchor plate 131 may have a rectangular shape. The area of the anchor plate 131 is smaller than the area of the upper end of the expanded head 101, and the anchor plate may be located above the expanded head when the pile head 101 and the precast reinforced concrete pile cap 103 are joined.
The anchor plate 131 may have a circular shape, is smaller than the area of the upper end of the pile head 101, and may have any shape as long as it is located above this upper end.

A through hole through which each of the tension members 161 penetrates may be provided at a predetermined position from the precast reinforced concrete pile cap 103 to the anchor plate 131.
Note that the through holes provided in the anchor plate 131 may be other than the four corners, and may be at any position as long as they do not collide with the seismic isolation device when the upper ends 161a of the tension members 161 project.

The tension member 161 may be a member for crimping the pile head 101 and the precast reinforced concrete pile cap 103, and may be, for example, a PC steel rod, a PC steel wire, or a high-strength reinforcing bar. The upper end 161a of the tension member 161 may have a screw shape.
Note that each of the tension members 161 may be previously provided for preventing splitting at the time of forming the pile, or may be inserted after forming the pile head 101, and when provided at the time of forming the pile, the positional relationship with the anchor plate 131 is required. You may arrange according to.

Next, an example of a construction method of the joint structure between the pile head and the seismic isolation device shown in FIG. 4 will be described.
It should be noted that description of the flow or procedures equivalent to those described with reference to FIGS. 2 and 3 will be omitted.

First, the exposed tip portion of the pile is cut by a predetermined method, and the remaining tip portion is used as the pile head 101. The tension members 161 are left uncut so as to project from the upper ends of the pile heads 101.

Next, non-shrink mortar (not numbered) is applied to the upper end of the pile head 101. Then, while passing each of the precast reinforced concrete pile caps 103 and tension member 161 into a through hole provided in the anchor plate 131, and places the precast reinforced concrete pile cap on the upper end of the pile head 101. After that, the non-shrink mortar is solidified, and the screw head is tightened downward from the upper end 161a of the tension member 161, so that the pile head 101 and the precast reinforced concrete pile cap 103 are tightly bound by each of the tension members 161. The pile head and the precast reinforced concrete pile cap may have a higher degree of joint than a semi-rigid joint.

As described above, in the joint structure of the pile head 101 and the seismic isolation device according to another embodiment of the present invention, the anchor plate 131 is provided on the upper surface of the precast reinforced concrete pile cap 103, and the tension member 161 is used for the precast. by Tightened the reinforced concrete pile cap and pile head, improved construction efficiency and bonding degree between the precast reinforced concrete pile cap and pile head, realizing a higher degree than the semirigid bonding. That is, since the anchor plate 131 is integrally provided, the seismic isolation device and the precast reinforced concrete pile cap 103 can be easily joined. Furthermore, the non-shrink mortar is interposed between the precast reinforced concrete pile cap 103 and the pile head 101, and is tightly connected by the tension member 161, so that the degree of joint between the precast reinforced concrete pile cap and the pile head is increased. , But to a higher degree than semi-rigid joints.

INDUSTRIAL APPLICABILITY The joint structure between the pile head and the seismic isolation device according to the present invention is widely applicable not only to collective housing but also to individual housing, corporate buildings, and industries related to medical facilities, nursing facilities, and the like.

1, 101 Pile head 2, 102 Seismic isolation device 3, 103 Precast reinforced concrete pile cap 31, 131 Anchor plate 32 Cotter 33 Recess 34 Non-shrink mortar 4 Connecting beam B Structure C Discard concrete

Claims (3)

A structure in which the pile head and the seismic isolation device are joined via a precast reinforced concrete pile cap ,
On the upper surface of the precast reinforced concrete pile cap , an anchor plate for joining with the seismic isolation device is integrally provided,
On the side surface of the precast reinforced concrete pile cap , a cotter for joining with the connecting beam is formed in a concave shape,
On the bottom surface of the precast reinforced concrete pile cap , a recess for molding the upper end of the pile head is formed,
On the upper surface or the side surface of the precast reinforced concrete pile cap, from the predetermined portion to the recess, a through hole for injecting non-shrink mortar is formed,
A non-shrinkable mortar is further interposed between the pile head and the precast reinforced concrete pile cap . A structure in which the pile head and the seismic isolation device are joined via a precast reinforced concrete pile cap ,
On the upper surface of the precast reinforced concrete pile cap , an anchor plate for joining with the seismic isolation device is integrally provided,
On the side surface of the precast reinforced concrete pile cap , a cotter for joining with the connecting beam is formed in a concave shape,
Between the pile head and the precast reinforced concrete pile cap , further non-shrink mortar is interposed,
A tension member having an upper end projecting from the anchor plate and a lower end fixed to the inside of the pile head tightly connects the precast reinforced concrete pile cap and the pile head. And seismic isolation device joint structure. The joining structure between a pile head and a base isolation device according to claim 2 , wherein the tension member is a steel wire or a reinforcing bar provided when the pile head is formed.

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