JP2001073391A - Pile-head structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of large bending moment in a foundation pile, while obviating the separation by floating of the foundation pile and an upper structure by vertical vibrations by expecting rigid-coupling strength between the foundation pile and the upper structure to small-to-medium scale earthquakes while a slip is generated on a contact interface between the foundation pile and the upper structure to a large-scale earthquake. SOLUTION: An upper spherical member 4 on the upper structure side, having a spherical surface 4a receiving the spherical surface 2a of a foundation-side spherical member 2, is superposed to the foundation-side spherical member 2 installed to the pile head 1a of a foundation pile 1. The upper spherical member 4 is connected at every proper interval in the peripheral direction, by connecting members 6 longer than a distance between opposite faces in a periphery to the foundation-side spherical member 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pile head connection structure in which the connection between a foundation pile and an upper structure changes according to the magnitude of an earthquake.

[0002]

2. Description of the Related Art Conventionally, when constructing a building such as a building, it is common practice to support an upper structure such as a building on a pile embedded in a supporting ground, thereby supporting the entire upper structure. . In the past, the pile head was rigidly connected to the building, but in this case, if a horizontal force is applied to the pile head during an earthquake, there is a great risk that the pile head will be destroyed. There was a problem that reinforcement such as expanding the diameter of the pile head was necessary.

On the other hand, in order to reduce the stress generated at the pile head,
A pin connection structure that releases the stress of the pile head by connecting the pile head relative to the building to release the stress of the pile head, and releases the stress of the pile head by allowing the pile head to slide with respect to the building Roller coupling structures have been proposed (for example, Japanese Patent Application Laid-Open Nos. 1-284613, 8-120687, and 10-227039).
No. 10-227040).

However, in this case, there is a problem that the displacement of the building is increased by connecting the pile head with a pin connection structure or a roller connection structure, and it is necessary to increase the structural strength of a beam or the like. was there. In addition, the vibration of the earthquake includes horizontal motion and vertical motion.In the case of an earthquake accompanied by severe vertical motion, in the case of the above-mentioned pile head joint structure, when the pulling force occurs, the pile head and the upper structure There was a problem that things floated away.

[0005]

According to the present invention, a rigid connection between a foundation pile and a superstructure can be expected for a small-scale earthquake, while a large-scale earthquake can be expected. Is
Sliding occurs at the contact interface between the foundation pile and the superstructure, preventing a large bending moment from being generated on the foundation pile. The object of the present invention is to prevent the upper structure from floating away.

[0006]

In order to achieve the above object, a pile head structure according to the present invention is characterized in that a base-side spherical member provided on a pile head of a foundation pile has an upper surface having a spherical surface for receiving the spherical surface of the base-side spherical member. The upper spherical member on the structure side is overlapped, and the upper spherical member is a connecting member that is longer than the peripheral facing distance of the base spherical member and is connected at appropriate intervals in the circumferential direction.

Therefore, according to the present invention, even when the axial force of the pile head greatly fluctuates due to the rocking action due to the earthquake, the two members are prevented from floating apart by the connecting member. In addition, since the connecting member is longer than the facing distance between the two spherical members, the two spherical members can slide or relatively rotate along the contact spherical surface by the lengthened portion, and the pile head and the pile at the underground portion of the pile are large. The generation of a bending moment can be prevented.

[0008]

Next, an embodiment of the present invention will be described. FIG. 1 is a sectional view showing a pile head structure according to an embodiment of the present invention, and FIG. 2 is an explanatory sectional view showing the relationship between a pile embedded in the ground and an upper structure. In FIG. 1, reference numeral 1 denotes a foundation pile embedded in a ground 5, and a foundation-side spherical member 2 having a convex spherical surface 2 a is attached to a pile head 1 a of the foundation pile 1 so that the spherical surface becomes an upper surface. . In the figure, reference numeral 2b denotes a joint for connecting the foundation side spherical member 2 and the foundation pile 1, and is formed in a cylindrical shape having an inner diameter for receiving the foundation pile 1.

Reference numeral 3 denotes an upper structure, for example, a building, and the lower surface of the upper structure 3 has a spherical surface 2a of the base-side spherical member 2.
An upper spherical member 4 having a concave spherical surface 4a for receiving the same is provided at a position corresponding to the base-side spherical member 2. Note that the relationship between the convex spherical surface 2a and the concave spherical surface 4a is such that the curvature radii of the convex spherical surface 2a and the concave spherical surface 4a are substantially equal to each other.
The radius of curvature may be slightly smaller than the radius of curvature, that is, the relationship may be any as long as the convex spherical surface 2a is received within the concave spherical surface 4a.

[0010] In the drawing, reference numeral 4 b denotes a mounting seat for the upper structure 3. Further, fastening holes 7... 7 for the connecting member 6 are provided at appropriate intervals along the circumferential direction on the outer periphery of the base-side spherical member 2 and the upper spherical member 4 so that bolt nuts, chains, connecting rods and the like are provided. It is connected by a connecting member 6 (bolt nut in the illustrated example). The connecting member 6 has a margin L so that the base side spherical member 2 and the upper spherical member 4 can be rolled as shown by the arrow R or slipped as shown by the arrow Q within a certain range via the contact spherical surface. Fastening is performed, and the fastening holes 7 are also formed as conical holes 7... 7 as shown in the drawing, so that an excessive force is not generated in the connecting member 6 during rolling.

Both the base-side spherical member 2 and the upper spherical member 4 are made of, for example, cast iron. The contact interface between the two is set to have a friction coefficient that does not cause a sliding movement at the mutual interface due to a load due to a small-to-medium-scale earthquake. It is configured such that it will slide only when an external force greater than that is applied.
In order to obtain such a friction coefficient, in the case of cast iron, the convex spherical surface 2a and the concave spherical surface 4a are roughened as cast, or a rough shot is formed by hitting both the convex spherical surface 2a and the concave spherical surface 4a with a steel shot. The surface is roughened with a peening hammer.

Further, as shown in FIG.
a and a concave groove (not shown) are formed on the surface of each of the grooves 2c in the form of a radial lattice to thereby provide an appropriate frictional resistance. Are provided on the surface of the convex spherical surface 2a) in the form of a large number of small protrusions 2d... 2d in a dispersed manner, and the concave surfaces 4d. Instead of the small projections 2d, as shown in FIG. 3 (c), concentric ridges 2e... 2e are provided on the surface of one spherical surface (a convex spherical surface 2a in the illustrated example) and the other spherical surface (a concave surface in the illustrated example). Concentric grooves 4e... 4e are provided at corresponding positions on the spherical surface 4a) to fit them together, and these small projections 2d and recesses 4d are formed.
The two spherical surfaces 2a, 4a do not move relative to each other with an external force less than a certain value due to the engagement of the protrusions 2e and the concave grooves 4e, and the first spherical surfaces 2a, 4a shift for the first time with an external force exceeding this, so that an appropriate friction resistance and You can also.

[0013] As means for setting an appropriate friction coefficient,
Although the case of roughening between the contact surfaces has been described, the present invention is not limited to this, and the contact area may be adjusted by a difference in curvature between the spherical surface 2a of the base-side spherical member 2 and the spherical surface 4a of the upper spherical member 4. A combination of the adjustment of the contact area and the rough surface may be used. Next, the operation of the present invention will be described.

As shown in FIG. 2, a foundation side spherical member 2 is fixed to a pile head 1a of a foundation pile 1 embedded in a hard ground or a supporting ground corresponding thereto as shown in FIG. Then
As shown in FIG. 1, the upper spherical member 4 is disposed on the base-side spherical member 2, and the periphery thereof is connected by a connecting member 6 with a margin L. Then, the upper structure 3 is constructed such that the mounting seat 4b of the upper spherical member 4 has a proper alignment posture with the upper structure 3.

After the construction, the weight of the upper structure 3 is supported by the foundation pile 1 at the contact interface between the basic spherical member 2 and the upper spherical member 4. Since the weight of the upper structure is added to the contact interface, the frictional resistance causes the base-side spherical member 2 and the upper spherical member 4 to remain firmly integrated with each other in a small-to-medium-scale earthquake. The structure is associative.

Next, when an external force exceeding the frictional resistance is applied in the case of a large-scale earthquake, the base-side spherical member 2 and the upper spherical member 4 relatively move within a margin L of the coupling member 6, The generation of a large bending moment is prevented. Furthermore, since the axial force of the pile head greatly fluctuates due to the locking action due to the large-scale earthquake, and the foundation pile 1 and the upper structure 3 are likely to be separated from each other, they are connected by the connecting member 6, Vertical vibration exceeding the allowance L is limited, and floating of the base-side spherical member 2 and the upper spherical member 4 is also prevented.

In the above embodiment, the foundation pile 1 is a steel pipe,
Although the case where a cast iron pipe or the like is driven is shown, as shown in FIG. 4, the same can be applied to a case where it is formed by casting concrete at a construction site. In FIG.
The pile 1 is composed of a reinforcing bar 1b arranged in an excavation hole 1d provided in the ground 5 and a concrete 1c cast. The upper surface of the pile 1 is filled with a level adjusting mortar 1e to be flattened. The iron plate 1f is screwed with a bolt and nut 1g using the upper end of the reinforcing bar 1b or the like, and a fastening member 6 is attached to the iron plate.
Thereby, the base-side spherical member 2 is fixed.

An upper spherical member 4 is fixed to a steel plate 3a or a reinforcing bar 3b constituting the upper structure in a foundation beam of the upper structure 3. In addition, in the figure, 10 is a chestnut stone and 11 is cast concrete for surface leveling. Also in this embodiment,
The foundation pile 1 and the upper structure 3 are supported by a convex spherical surface 2a and a concave spherical surface 4a, and have a rigid structure during a small-scale earthquake, and relatively move within a margin L of the coupling member 6 during a large-scale earthquake, The generation of a large bending moment is prevented. Also,
The connecting member functions as a floating prevention structure.

As another configuration example of the above embodiment, FIG.
As shown in (1), the spherical surface 2a of the base-side spherical member 2 may be a concave spherical surface, and the spherical surface 4a of the upper spherical member 4 may be a convex spherical surface. In addition,
The structure shown in FIG. 5 is the same as the structure shown in FIG. 1 except for the unevenness of the spherical surfaces 2a and 4a, and therefore the same reference numerals are given and the detailed description is omitted.

Another connection structure between the base-side spherical member 2 and the upper spherical member 4 may be a structure as shown in FIGS. 6 (a) and 6 (b). In other words, on the periphery of the base-side spherical member 2, there is formed a locking groove 2c having a lower convex portion having a wide convex shape as shown in FIG. 6B, and a convex character fitted into the groove 2c. A locking member 6a having a base portion is fitted and fixed with bolts 12, and a window hole 6b formed on the upper portion of the locking member 6a is inserted into a window hole 6b as shown in FIG.
As shown in (a), a locking projection 4c projecting radially from the periphery of the upper spherical member 4 is inserted into the window hole 6b.
May be made larger than the cross section of the locking projection 4c to provide a margin L.

In this case, floating is prevented by the engagement between the locking projection 4c and the window hole 6b. 6 (a) and 6 (b)
In FIG. 1, members denoted by the same reference numerals as those in FIG. 1 indicate the same or corresponding members as those shown in FIG. Further, as shown in FIGS. 7A, 7B, and 7C, engagement holes 2e having an L-shaped bent cross section at the peripheral edge 2d of the base-side spherical member 2 as shown in FIG. 7C. 7 (a) and 7 (c), a connecting member 6d having a hook portion 6c which engages with the engaging hole 2e is integrally formed on the periphery of the upper spherical member 4 to protrude therefrom. The upper spherical member 4 may be placed on the spherical member 2 so as to be engaged and attached by rotating in the direction of arrow S as shown in FIG. 7C.

The lifting of the upper spherical member is caused by the hook portion 6c.
Is prevented from being engaged with the L-shaped engagement hole 2e.
In the case of this embodiment, the mounting of the upper spherical member 4 becomes possible with a one-touch method, and the construction is facilitated. In FIGS. 7A to 7C, members denoted by the same reference numerals as those in FIG. 1 indicate the same or corresponding members as those shown in FIG.

[0023]

As described above, according to the present invention, when a superstructure such as a building is supported by foundation piles, a rigidly-coupled structure is used for a small-scale earthquake and a certain size is used for a large-scale earthquake. Since the structure has the function of sliding while transmitting the bending moment, it is not necessary to take measures such as expanding the pile head, and it is not necessary to increase the sectional performance of the pile. In addition, even when the axial force of the pile head greatly fluctuates due to the rocking action due to the earthquake, there is an effect that the floating is prevented by the connecting member.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a main part showing an embodiment of the present invention.

FIG. 2 is an explanatory sectional view showing a relationship between a pile and an upper structure.

FIGS. 3A and 3B are main part explanatory diagrams showing another configuration example for achieving an appropriate frictional resistance in the embodiment, where FIG. 3A is a radiation groove, FIG. 3B is a projection, and FIG. The frictional resistance is increased by ridges.

FIG. 4 is an essential part enlarged cross-sectional view showing another configuration example of the embodiment of the present invention.

FIG. 5 is an enlarged sectional view of a main part showing still another configuration example of the embodiment of the present invention.

FIGS. 6A and 6B are partial explanatory views showing another configuration example of the embodiment of the present invention, wherein FIG. 6A is a side sectional view, and FIG.
FIG. 3 is a cross-sectional view taken along line b.

FIGS. 7A and 7B are partial explanatory views showing still another configuration example of the embodiment of the present invention, wherein FIG. 7A is a side sectional view, FIG. 7B is a plan view, and FIG. 7C is cc in FIG. It is an important section expanded sectional view of a line.

[Explanation of symbols]

 Reference Signs List 1 foundation pile 1a pile head 2 foundation side spherical member 2a convex spherical surface 3 upper structure 4 upper spherical member 4a concave spherical surface 6 connecting member 7 connecting hole for connecting member L margin

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Otsuki 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Masayoshi Sato 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation Co., Ltd. (72) Inventor Eiji Wakita 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation (72) Inventor Hideyuki Mano 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Corporation ( 72) Inventor Toshiyuki Iwamoto 2-26 Ohama-cho, Amagasaki-shi, Hyogo Pref. In Kubota Mukogawa Works, Ltd. (72) Inventor Noriyuki Arakawa 2-26, Ohama-cho, Amagasaki-shi, Hyogo Pref. Inventor Masayuki Okawa 2-26, Ohama-cho, Amagasaki-shi, Hyogo F-term in Kubota Mukogawa Works, Ltd. (reference) 2D041 AA01 AA02 BA19 BA37 DA01 DB02 D B06 2D046 CA03 DA11

Claims (1)

[Claims] An upper structure-side upper spherical member having a spherical surface for receiving the spherical surface of the base-side spherical member is superimposed on a base-side spherical member provided at a pile head of the foundation pile, and the upper spherical member is formed of a material. A pile head structure that is connected to the base-side spherical member at an appropriate interval in the circumferential direction with a connecting member that is longer than the facing distance of the peripheral edge.