JP4296537B2 - Joining structure and joining method of ready-made pile and superstructure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a joining structure and a joining method between a ready-made pile and an upper structure such as a footing supported by the pile.
[0002]
[Prior art]
Conventionally, on the basis of reliably transmitting the load of the upper structure to the foundation pile, for example, a joint structure of a ready-made pile and the upper structure as shown in FIG. 2 has been adopted. A joining structure 100 shown in FIG. 2 includes a pile head 101a and an upper structure 102 of a pile 101, a PC steel material 104 provided in the pile body 103, a reinforcing steel bar 105 provided in the pile head 101a, or a pile. The joint structure 100 is tightly connected by the center-filled reinforcing steel bars 106 provided on the inner side of the pile body 103 in the head 101a, and thus the joint structure 100 is regarded as a rigid connection or a hinge connection depending on the amount of PC steel and the reinforcing steel bars. Is possible.
[0003]
Also, in recent years, the pile head and the foundation are not rigidly coupled, but are semi-rigidly coupled or substantially pin-coupled, allowing the relative rotation of the pile head. And a structure for reducing bending stress generated in the foundation has been proposed. This structure consists of a structure in which a transmission stress reducing device for reducing the stress transmitted from the pile head to the upper structure is interposed between the pile head and the upper structure. According to this joint structure, it is possible to respond reasonably even during a large-scale earthquake, and the seismic performance of the building is improved. (For example, refer to Patent Document 1).
[0004]
[Patent Document 1]
JP 2003-27499 A (page 3-4, FIG. 1)
[0005]
[Problems to be solved by the invention]
However, according to the conventional joint structure described above, since the relative rotation of both the pile 101 and the upper structure 102 is restricted, a large bending stress is generated at the pile head joint during an earthquake or the like. Therefore, the pile head 101a and the upper structure 102 (footing) need to be robust because they require not only axial strength but also bending strength, and there is a problem that the structure itself becomes complicated.
[0006]
In the present invention, the above-described conventional problems are taken into consideration, and the transmission stress reduction device improves the seismic performance of the joint structure between the pre-made pile and the upper structure, and easily and reliably installs the transmission stress reduction device. Thus, an object of the present invention is to provide a bonding structure and a bonding method between a ready-made pile and an upper structure, which can reduce the cost and shorten the work period.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a prefabricated pile and an upper portion in which a transmission stress reducing device is interposed between a hollow prefabricated pile and an upper structure formed above the prefabricated pile. In the joining structure with the structure, a disk-shaped lid is put on the upper end of the pile head of the ready-made pile, and a stud bolt is erected on the upper surface of the lid, and on the bottom of the lid A rib portion fitted into the pile head, and the transmission stress reduction device is fixed to the stud bolt and fixed to an anchor material protruding downward from the lower surface of the upper structure , The rib portion is formed in a cross beam shape in the center of the lid portion, and is arranged vertically below the stud bolt .
[0008]
With such a feature, the stud bolt for fixing the transmission stress reduction device is projected from the pile head, and the lid portion deformed by the load of the upper structure and the transmission stress reduction device is reinforced by the rib portion.
In addition, the center of the lid portion where the load in the vertically downward direction acts most effectively is reinforced by the rib-shaped rib portion.
[0011]
The invention according to claim 3 is a prefabricated pile and an upper structure in which a hollow prefabricated pile and an upper structure formed above the prefabricated pile are joined via a transmission stress reducing device that reduces the transmission of stress. In the joining method, a stud bolt is erected in advance on the upper surface of the disc-shaped lid portion, and is fitted into the pile head of the ready-made pile at the center of the bottom surface of the lid portion and arranged vertically below the stud bolt. A rib- like rib portion is suspended, and the lid is placed on the upper end of the pile head after placement of the ready-made pile, and the transmission stress reduction device is fixed to the stud bolt. And forming the upper structure.
[0012]
Due to these features, the stud is pre-attached with stud bolts and ribs. After placing the ready-made pile, cover the top of the pile head with the lid and just fix the transmission stress reduction device to the stud bolt. The transmission stress reduction device is installed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a joining structure and a joining method between a ready-made pile and an upper structure according to the present invention will be described based on the drawings.
[0014]
FIG. 1 is a sectional view of the structure of a pile head joint according to the present invention. In this figure, reference numeral 1 denotes a hollow steel pipe pile driven into the ground G. Between the pile head 2 of this steel pipe pile 1 and the footing 3 which is the base part of the upper structure supported by the steel pipe pile 1, they are substantially pin-coupled while allowing their relative rotation. A transmission stress reducing device 4 is interposed.
[0015]
The mounting structure of the transmission stress reducing device 4 will be described. The inside of the pile head 2 of the steel pipe pile 1 is hollow, and the top of the pile head 2 is covered with a plate-like lid portion 5. The lid 5 is formed from a steel plate having a shape (round shape) slightly larger than the horizontal cross-sectional shape of the pile head 2, and is placed on the upper end surface of the pile head 2.
[0016]
A plurality of stud bolts 6 extending upward are erected on the upper surface of the lid portion 5, and a rib portion 7 fitted into the pile head 2 is suspended from the bottom surface of the lid portion 5. The rib portion 7 is attached so that a steel plate formed in a cross beam shape is orthogonal to the lid portion 5, and is disposed vertically below the stud bolt 6. Thereby, it is possible to effectively counter the load acting on the lid portion 5 from the stud bolt 6. Further, in order to prevent the lid 5 from shifting in the horizontal direction, the bottom surface of the lid 5 and the upper end surface of the pile head 2 are welded along the outer periphery of the pile head 2.
[0017]
Above the lid portion 5, a transmission stress reduction device 4 is installed via a leveling mortar portion 8 made of a non-shrink mortar for level adjustment. The transmission stress reducing device 4 includes a ball seat 9 having a sliding surface as a part of a spherical surface, an upper lid 10 that is mounted on the ball seat 9 and supported so as to be swingable in all directions, and a high-strength bolt that connects them. 11, a nut 12 and a spherical washer 13. Thus, since the ball seat 9 and the upper lid 10 can swing in all directions in the connected state, the axial force is transmitted between the pile head 2 and the footing 3 and their relative rotation is performed. Acceptable. A plurality of bolt holes 9b are formed in the outer peripheral flange portion 9a of the ball seat 9 at intervals in the circumferential direction, and stud bolts 6 are respectively inserted into these bolt holes 9b. A ball seat fixing nut 14 is screwed onto the upper end of the stud bolt 6 above the bolt hole 9b.
[0018]
A plurality of bolt holes 10b are formed in the outer peripheral flange portion 10a of the upper lid 10 at intervals in the circumferential direction. The bolt holes 10b are anchors made of reinforcing bars protruding downward from the bottom surface of the footing 3. The lower end of the material 15 is inserted. The anchor material 15 has an upper end fixed in the footing 3, a lower end protruding below the footing 3, and a male thread formed on the lower end. An upper lid fixing nut 16a is double screwed to the lower end portion of the anchor material 15 below the bolt hole 10b, and an upper lid fixing nut 16b is screwed to the lower end portion of the anchor material 15 above the bolt hole 10b. .
[0019]
A protective cover 17 that protects the transmission stress reduction device 4 is provided around the transmission stress reduction device 4. The protection cover 17 is formed between the footing 3 and the leveling mortar portion 8 so as to surround the transmission stress reduction device 4. Is intervening. Moreover, the footing 3 is formed on the discarded concrete 18 formed on the ground G, and makes it easy to move the transmission stress reducing device 4 between the discarded concrete 18 and the upper end portion of the steel pipe pile 1. A floor sand 19 is formed .
[0020]
Next, a method of joining the steel pipe pile 1 and the footing 3 using the above-described transmission stress reducing device 4 will be described.
[0021]
First, before placing the steel pipe pile 1, the stud bolt 6 is erected in advance on the upper surface of the lid portion 5, and the rib portion 7 is vertically suspended on the bottom surface of the lid portion 5. The stud bolt 6 and the rib portion 7 are joined firmly by welding.
[0022]
Next, the steel pipe pile 1 is placed in the ground G. And the ground G of the part which laid the steel pipe pile 1 is dug, and while the pile head from the upper end surface to about 100 mm is taken out from the ground G, the soil etc. in the pile head 2 are dug, and the pile head 2 Make the inside hollow. Then, the upper end surface of the pile head 2 is covered with the lid portion 5 to which the stud bolt 6 and the rib portion 7 are previously attached, the bottom surface of the lid portion 5 and the upper end surface of the pile head portion 2 are butted together, and the pile head portion The fillet is welded along the outer periphery of 2.
[0023]
Next, the transmission stress reduction device 4 is disposed above the lid 5. At this time, the transmission stress reducing device 4 is arranged with a gap between the ball seat 9 and the lid 5. Further, the stud bolts 6 erected on the lid portion 5 are respectively inserted into a plurality of bolt holes 9 b formed in the outer peripheral flange portion 9 a of the ball seat 9. Then, the ball seat fixing nut 14 is screwed onto the stud bolt upper end portion above the bolt hole 9b, and the ball seat fixing nut 14 is tightened to fix the transmission stress reducing device 4.
[0024]
Next, a frame (not shown) surrounding the gap between the ball seat 9 and the lid 5 is provided on the upper surface of the lid 5, non-shrinking mortar is injected from an inlet provided in the frame, and the leveling mortar 8 is Form. The error of the height level of the pile head 2 is adjusted by the thickness of the leveling mortar 8, and the transmission stress reducing device 4 can be fixed at a predetermined position by the stud bolt 6, so Can be placed.
[0025]
Next, the lower end portions of the second anchor members 15 are respectively inserted into the plurality of bolt holes 10b formed in the outer peripheral flange portion 10a of the upper lid 10. The upper lid fixing nut 16a is double screwed to the lower end portion of the second anchor material 15 below the bolt hole 10b, and the upper lid fixing nut 16b is screwed to the lower end portion of the anchor material 15 above the bolt hole 10b. The transmission stress reducing device 4 is fixed by sandwiching the flange portion 10a between the upper lid fixing nuts 16a and 15b.
[0026]
Next, a protective cover 17 is attached around the transmission stress reducing device 4, and the periphery immediately above the pile is backfilled with the spread sand 19, and then the discarded concrete 18 is formed. Then, after the discarded concrete 18 is solidified, a footing reinforcing bar (not shown) is arranged on the discarded concrete 18 and a formwork (not shown) is built, and fresh concrete is placed in the formwork to form the footing 3. . In the lower end portion of the footing 3, the upper end portion of the transmission stress reducing device 4 and the upper end portion of the anchor material 15 are provided integrally with the footing 3.
[0027]
According to the joining structure of the steel pipe pile 1 and the footing 3 described above, since the transmission stress reducing device 4 is interposed between the steel pipe pile 1 and the footing 3, the transmission stress reducing device 4 improves the seismic performance. be able to. In addition, the transmission stress reduction device 4 is fixed to the stud bolt 6, and the stud bolt is erected on the upper surface of the lid portion 5 that covers the upper end surface of the pile head 2, so that the transmission stress reduction device 4 is fixed. Since the stud bolt is simply and reliably provided on the pile head 2, it is possible to reduce the cost and shorten the construction period.
[0028]
Moreover, since the rib part 7 is hung from the bottom face of the cover part 5, the deformation | transformation of the cover part 5 by the load which acts on the perpendicular downward direction is suppressed. Accordingly, it is not necessary to increase the thickness of the lid portion 5, the steel plate constituting the lid portion 5 can be designed to be thin, and a structure that can withstand a large load is obtained. Moreover, since the rib part 7 is formed in the center of the cover part 5 in the shape of a cross-beam, it can oppose effectively with respect to the load which acts on the cover part 5, and is applied also when a bigger load arises. be able to.
[0029]
Moreover, according to the joining method of the above-mentioned steel pipe pile 1 and the footing 3, the stud bolt 6 and the rib part 7 are previously attached to the lid part 5, and this lid part is attached to the pile head 2 after the ready-made pile driving. The stud bolt 6 for fixing the transmission stress reducing device 4 is provided on the pile head 2 by covering the upper end. As a result, the work of installing the transmission stress reducing device 4 at the site is simplified, and the construction period can be shortened.
[0030]
As mentioned above, although embodiment of the joining structure and joining method of the ready-made pile and upper structure concerning this invention was described, this invention is not limited to above-described embodiment, The range which does not deviate from the meaning It can be changed as appropriate. For example, in the above-described embodiment, the present invention has been described by taking the steel pipe pile 1 as an example of a hollow ready-made pile. However, the present invention is not limited thereto, and the present invention is also applied to a ready-made pile such as a PC pile, a PHC pile, or an SC pile. Applicable. Moreover, in the above-described embodiment, the steel pipe pile 1 is constructed by the hammering method, but the present invention is not limited to the hammering method, and the steel pipe pile 1 is not limited to the hammering method, for example, by the pre-boring method or the digging method. You may construct. In the embodiment described above, the present invention has been described by taking the footing 3 as an example of the upper structure. However, the present invention is not limited to this, and the present invention can also be applied to a base bottom plate and a column base.
[0031]
In the above-described embodiment, a steel plate is used for the rib portion 7, but the rib portion 7 may be formed of an angle material, a channel material, groove type steel, or various steel materials. Further, in the above-described embodiment, the rib portion 7 is joined to the lid portion 5 by welding, but the present invention may use one in which the lid portion 5 and the rib portion 7 are integrally formed.
[0032]
【The invention's effect】
According to the joining structure and joining method between the ready-made pile and the upper structure according to the present invention described above, the transmission stress reduction device can improve the earthquake resistance, and the stud bolt is put on the pile head. Since the stud bolt for fixing the transmission stress reduction device is easily installed, and the rib part is suspended from the bottom of the lid, it is resistant to deformation caused by a vertical load. The lid is reinforced, and the transmission stress reduction device is securely installed at a predetermined position and the upper structure is reliably supported. As a result, cost reduction and construction period reduction can be achieved.
[0033]
In addition, since the rib portion is formed in a cross beam shape at the center of the lid portion, reinforcement against a vertical load acting on the lid portion is effectively performed. Thereby, it is not necessary to increase the bending strength of the lid portion, and the material cost of the lid portion is reduced.
Moreover, since the rib part is arrange | positioned vertically under the stud bolt, it can counter effectively the load which acts on a cover part from a stud bolt.
[0034]
Further, since the stud bolt and the rib portion are attached to the lid portion in advance, it is only necessary to cover the lid portion provided with the stud bolt and the rib portion on the site, and the field work is simplified. Thereby, the construction period can be shortened.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view for explaining an embodiment of a joining structure and joining method between a ready-made pile and an upper structure according to the present invention.
FIG. 2 is a cross-sectional view for explaining an embodiment of a joining structure and joining method of a conventional ready-made pile and an upper structure.
[Explanation of symbols]
1 Steel pipe pile (off-the-shelf pile)
2 Pile head 3 Footing (superstructure)
4 Transfer Stress Reduction Device 5 Lid 6 Stud Bolt 7 Rib 15 Anchor Material

Claims (2)

In the joint structure between the prefabricated pile and the upper structure in which a transmission stress reduction device for reducing the transmission of stress is interposed between the hollow prefabricated pile and the upper structure formed above the prefabricated pile,
A top of the pile head of the ready-made pile is covered with a plate-like lid, a stud bolt is erected on the upper surface of the lid, and the bottom of the lid is fitted into the pile head And the transmission stress reduction device is fixed to the stud bolt and fixed to an anchor material protruding downward from the lower surface of the upper structure ,
The said rib part is formed in the center of the said lid part in the shape of a cross-beam, and is arrange | positioned perpendicularly below the said stud bolt, The joining structure of the ready-made pile and upper structure characterized by the above-mentioned. In the joining method of the ready-made pile and the upper structure in which the hollow ready-made pile and the upper structure formed above the ready-made pile are joined via a transmission stress reduction device that reduces the transmission of stress.
A stud-shaped rib portion that is erected in advance on the upper surface of the disc-shaped lid portion and is fitted into the pile head of the ready-made pile at the center of the bottom surface of the lid portion and is disposed vertically below the stud bolt. After placing the ready-made pile, the upper end of the pile head is covered with the lid, the transmission stress reducing device is fixed to the stud bolt, and the upper structure is mounted on the transmission stress reducing device. A method of joining a prefabricated pile and an upper structure characterized by forming.

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