JP3800535B2 - Pile-column connection structure and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure and a method for joining a PHC pile and a steel column without requiring a footing or a foundation beam.
[0002]
[Prior art]
As is well known, building piles and pillars are joined via foundations (footing, foundation beams, etc.), but in recent years, the foundations have been omitted for the purpose of shortening the construction period and reducing costs. Attempts have been made to join columns directly. As such a construction method, for example, as shown in Patent Document 1 and Patent Document 2, a hollow pile is adopted as a pile, a column base is inserted into the pile head, and concrete or mortar is filled into the pile head. The one that integrates the pile head and the column base has been proposed.
[0003]
[Patent Document 1]
JP 2001-295286 A
[Patent Document 2]
JP2002-138495
[0004]
[Problems to be solved by the invention]
However, in all the conventional methods described above, since the column base is inserted into the pile head, it is necessary to increase the diameter of the entire pile more than necessary, or to enlarge the diameter of the pile head. Since the thing shown by patent document 1 requires a special joining metal fitting, there existed room for improvement in those points.
[0005]
In view of the above circumstances, the present invention employs a PHC pile as a pile and a steel column as a column, and an effective and appropriate structure for reliably and easily joining the PHC pile and the steel column without using a foundation. The purpose is to provide a construction method.
[0006]
[Means for Solving the Problems]
The invention of claim 1 is a joining structure of a PHC pile and a steel column, and a joined steel pipe having the same outer diameter as that of the PHC pile is fixed to the top end plate of the PHC pile, and the steel column is inserted into the joined steel pipe. and column base is inserted, column base by concrete filled in the bonding steel tube is fixed to the bonding steel pipes, posts axial force by the engagement between the concrete and the top end plate can be transmitted to the PHC pile The insertion length of the column base into the bonded steel pipe is set to 1.5 times the column width or more, and a dimension of 1/4 or more of the pile diameter is secured between the column base and the pile head. It is characterized by.
[0008]
The invention of claim 2 is characterized in that, in the invention of claim 1, a base plate is provided on a column base of the steel column, and a center hole is formed in the base plate.
[0009]
The invention of claim 3 is a method for joining a pile and a column to be joined by the joining structure according to claim 1 or 2, wherein a PHC pile in which a joining steel pipe is fixed to a top end plate in advance is underground. After embedment, a steel column is installed, and its column base is temporarily supported in a state where it is inserted into the jointed steel pipe. Concrete is placed and filled in the jointed steel pipe. As a temporary jig for temporary support, a cross-shaped support frame is used.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the joint structure of the present invention are shown in FIGS. In this embodiment, while adopting the PHC pile 1 as the pile, the steel column 2 is adopted as the column, and the PHC pile 1 and the steel column 2 are joined via the joining steel pipe 3 and the concrete 4 filled therein. It is what I did.
[0013]
As shown in FIG. 1, a PHC pile (pre-tension type centrifugal force prestressed concrete pile) 1 has a hollow cylindrical shape, and an annular top end plate 5 is provided at the upper end thereof. A soil cement 6 in which soil and cement milk are suspended is filled. In the present embodiment, a steel pipe column having a square cross section is adopted as the steel column 2, a base plate 7 is provided at the lower end (column base), and a center hole 8 is formed in the base plate 7.
[0014]
The outer diameter φ of the bonded steel pipe 3 is the same as that of the PHC pile 1, and the lower end of the bonded steel pipe 3 is coaxially connected to the top end plate 5 while being coaxial with the PHC pile 1. As shown in FIG. 2, since the wall thickness ts of the bonded steel pipe 3 is smaller (thin) than the wall thickness tp of the PHC pile 1, when the bonded steel pipe 3 is bonded to the PHC pile 1, they are placed inside the bonded portion. A level difference corresponding to the wall thickness difference δt is generated, and therefore the concrete 4 filled in the bonded steel pipe 3 is engaged with the stepped portion, and the top end plate 5 serves as a bearing surface from the concrete 4 to the PHC pile 1. Force is transmitted reliably.
[0015]
And the lower end part (column base part) of the steel column 2 is inserted in the inside of the joining steel pipe 3, and concrete 4 is cast and filled in the whole inside of the joining steel pipe 3, and the inside of the column base part of the steel column 2 Further, the concrete 4 is filled to the same level, and the column base is firmly fixed to the bonded steel pipe 3 by the concrete 4. Here, as shown to Fig.1 (a), the insertion length of the column base part in the joining steel pipe 3 is set to 1.5 times or more of the column width dimension B, and it is between a column base and a pile head. Is secured at least 1/4 of the pile diameter φ of the PHC pile 1.
[0016]
According to the above-mentioned joint structure, the column base portion of the steel column 2 is inserted into the joint steel pipe 3 joined to the pile head of the PHC pile 1 and fixed by the concrete 4, so that the steel column 2 is securely attached to the PHC pile 1. It is possible to secure a sufficient bonding strength. In particular, since the steel column 2 is provided with a base plate 7, a step portion to which the concrete 4 is engaged is naturally formed in the joint portion between the joint steel pipe 3 and the PHC pile 1 due to a difference in thickness between them. Even if a shear key such as a stud or wing plate is not specially provided on the column base, the column axial force is reliably transmitted from the steel column 2 to the PHC pile 1 via the concrete 4 as shown by the arrows in FIG. The Moreover, by setting the insertion length of the column base part to the bonded steel pipe 3 and the dimension between the column base and the pile head as described above, the steel column 2 and the PHC via the concrete 4 and the bonded steel pipe 3 are set. Bending and shearing are also effectively transmitted to and from the pile 1.
[0017]
And since the thing of the same outer diameter as the pile diameter (phi) of the PHC pile 1 is used as the joining steel pipe 3, and it is welded directly with respect to the top end plate 5, the steel column 2 is inserted. The internal dimensions of the bonded steel pipe 3 are naturally larger than the internal dimensions of the PHC pile 1, and there is no need to increase the pile diameter more than necessary or to expand the pile head as in the prior art. The ground moment and pile head moment generated in the PHC pile 1 does not increase suddenly, so it is structurally rational, and the amount of excavated soil during pile construction can be reduced, which is advantageous in terms of workability. It is. Of course, the welding of the joining steel pipe 3 to the PHC pile 1 can be easily and accurately performed at the factory when the pile is manufactured, and the only necessary material is the joining steel pipe 3 and the concrete 4 filled therein. The construction is not troublesome and is not expensive.
[0018]
A construction procedure for joining the PHC pile 1 and the steel column 2 with the above structure will be specifically described with reference to FIGS. First, as shown in FIG. 3, when the PHC pile 1 is manufactured, the joining steel pipe 3 is welded and joined to the top end plate 5. And the peeling tape 10 is affixed on the surface of the top end plate 5, and the lead wire 11 is extended to the outer side of the joining steel pipe 3 so that the peeling tape 10 can be easily peeled in a post process.
[0019]
Ordinary PHC pile construction method, for example, an intermediate drilling method in which an auger is inserted into the hollow part of the PHC pile 1 and the PHC pile 1 is buried while excavating and earthing, and the soil cement 6 is filled into the hollow part when the auger is pulled As shown in FIG. 4, the PHC pile 1 is put into the ground by a pre-boring method in which the pile hole is pre-excavated, the cement milk 6 is poured into the hole from the bottom, the auger is pulled out, and the PHC pile 1 is inserted. Buried. And after removing the soil cement 6 from the inside of the joining steel pipe 3 and cleaning the inside, the lead wire 11 is pulled, the peeling tape 10 is peeled off, and the clean surface of the top end plate 5 is exposed in the joining steel pipe 3. . Further, a support frame 12 as a temporary jig for installing the steel column 2 is installed on the bonded steel pipe 3. As shown in (c), the support frame 12 can be easily disassembled by connecting a total of four connecting members 14 above and below the two channel members 13 with bolts and assembling them in a cross-beam shape and removing the bolts. It can be positioned and temporarily supported through the steel column 2 inside thereof.
[0020]
As shown in FIG. 5, a mounting piece 15 made of an angle material or the like is previously welded to the peripheral surface of the lower end portion of the steel column 2, and the level adjustment bolt 17 is directed downward with respect to the nut 16 welded to the mounting piece 15. Screw it on. Then, the column base portion of the steel column 2 is inserted into the support frame 12, and the horizontal positioning and level adjustment are performed while temporarily supporting the weight of the steel column 2 with the support frame 12 via the level adjustment bolt 17. Do. After that, the concrete 4 is filled into the entire bonded steel pipe 3 and the concrete 4 is also filled into the steel column 2 to the same level. At this time, if the center hole 8 having a sufficiently large size is formed in the base plate 7, the top ends of the concrete 4 inside and outside the steel column 2 are naturally aligned, and the buoyancy of the concrete 4 is placed in the steel column 2 when the concrete 4 is placed. It can prevent acting. When the curing period elapses until a predetermined concrete strength is developed, the support frame 12 is disassembled and removed, and if necessary, the attachment piece 15 is melted from the steel column 2 to complete the joining operation. Note that the attachment piece 15 may be left as it is without fusing unless it is in the way. Further, the lower connecting material 14 of the support frame 12 may be buried in the concrete 4.
[0021]
According to the above construction method, the PHC pile 1 and the steel column 2 can be securely connected only by inserting the column base portion of the steel column 2 into the jointed steel pipe 3 welded to the pile head of the PHC pile 1 and placing the concrete 4 therein. It can be rigidly joined, and is extremely excellent in workability without requiring any special equipment or skill for construction. In particular, since the peeling tape 10 is previously applied to the top end plate 5 of the PHC pile 1 and the peeling tape 10 is peeled off before the concrete 4 is placed, the surface of the top end plate 5 is soiled. It is possible to reliably prevent a foreign matter such as cement from remaining and impairing the function as a bearing surface by a simple method. In addition, since the temporary support frame 12 is used when the steel column 2 is installed, the positioning and temporary support of the steel column 2 can be performed easily and safely, and the support frame 12 is complicated. Since it is not a thing, it can be manufactured at low cost, and it can be repeatedly used. Therefore, only the attachment piece 15 attached to the steel column 2 is used as a waste material, which is also reasonable in this respect.
[0022]
Although the embodiment of the present invention has been described above, the above embodiment is merely an example, and the present invention is not limited to the above embodiment, and various design changes are possible. Various modifications and application examples can be considered.
[0023]
In the above embodiment, the bonded steel pipe 3 is welded to the top end plate 5 of the PHC pile 1, but other fixing means such as fitting and joining by bolt fastening instead of welding may be used.
[0024]
In the above embodiment, a square steel pipe column is adopted as the steel column 2. However, it goes without saying that the present invention can be similarly applied not only to a circular steel tube column but also to a steel column having an appropriate cross section such as H-shaped steel. Further, when adopting a steel pipe column, it is preferable to fill the column base with concrete as in the above embodiment, but if the thickness of the steel pipe column is large, the concrete filling may be omitted. good. The presence or absence of the base plate and the presence or absence of the center hole of the base plate are arbitrary. In addition, if necessary, it does not prevent adding a stud or the like as a shear key to the concrete 4 to the inner surface or the column base portion of the bonded steel pipe 3.
[0025]
When the top end plate 5 can be cleaned by other methods when filling concrete, the peeling tape in the above embodiment may be omitted, or an appropriate cover may be removably attached instead. It's okay to keep things. Also, the support frame 12 as a temporary jig used when the steel column 2 is built can adopt any appropriate form as long as it can be positioned while temporarily supporting the steel column 2.
[0026]
【The invention's effect】
Since the invention of claim 1 is a structure in which a bonded steel pipe is fixed to the top end plate of the PHC pile, and the column base of the steel column is inserted into the inside and fixed by concrete, the column has a very simple and clear structure. Can be securely joined to the pile. In particular, the concrete is engaged with the pile head by the level difference caused by the thickness difference between the PHC pile and the bonded steel pipe, and the top end plate serves as a bearing surface, so that the column axial force can be reliably transmitted through the concrete. it can. Moreover, since the thing with the same outer diameter as a pile diameter was used as a joining steel pipe, the pile diameter of a pile head or the whole pile does not become larger than necessary.
[0027]
In addition, the length of the column base inserted into the bonded steel pipe was set to 1.5 times the column width or more, and a dimension of 1/4 or more of the pile diameter was secured between the column base and the pile head. Therefore, not only the axial force but also bending and shearing can be effectively transmitted between the steel column and the pile through the bonded steel pipe and concrete.
[0028]
In the invention of claim 2 , since the base plate is provided on the column base of the steel column, the transmission of the column axial force from the steel column to the concrete can be performed more reliably, and the center hole is formed in the base plate. In addition, it is possible to prevent buoyancy during concrete placement from acting on the steel column.
[0029]
The invention of claim 3 , after embedding a PHC pile in which the bonded steel pipe is fixed to the top end plate in advance, the steel column is built and the column base is temporarily supported in a state of being inserted into the bonded steel pipe, Since concrete is cast and filled in the jointed steel pipe, piles and columns can be reliably joined without requiring any special equipment or skill, and it is extremely excellent in workability. It can contribute greatly.
[0031]
In addition, since a cross-beam-shaped support frame is used as a temporary jig for positioning and temporary support when building a steel column, not only can the steel column be built easily and safely, but also the support The frame is reasonable because it can be manufactured at low cost and can be used repeatedly.
[Brief description of the drawings]
FIG. 1 is an elevational sectional view and a horizontal sectional view showing an embodiment of a joining structure of the present invention.
FIG. 2 is an enlarged view of a main part (II part in FIG. 1A).
FIG. 3 shows an embodiment of the joining method of the present invention, and is a view showing a state in which a joined steel pipe is attached to a PHC pile.
FIG. 4 is a view showing a state in which a PHC pile is buried in the ground.
FIG. 5 is a view showing a state in which a steel column is built and filled with concrete.
[Explanation of symbols]
1 PHC pile 2 Steel column 3 Bonded steel pipe 4 Concrete 5 Top end plate 6 Soil cement 7 Base plate 8 Center hole 10 Peeling tape 11 Lead wire 12 Support frame 13 Channel material 14 Connecting material 15 Mounting piece 16 Nut 17 Level adjustment bolt B Column width Dimensions φ Pile diameter

Claims (3)

It is a joint structure of PHC pile and steel column, and the joint steel pipe whose outer diameter is the same as PHC pile is fixed to the top end plate of PHC pile, and the column base part of the steel column is inserted into the joint steel pipe The column base is fixed to the bonded steel pipe by the concrete filled in the bonded steel pipe, and the column axial force can be transmitted to the PHC pile by the engagement between the concrete and the top end plate .
The insertion length of the column base into the bonded steel pipe is set to 1.5 times the column width dimension or more, and a dimension of 1/4 or more of the pile diameter is secured between the column base and the pile head. A pile-column connection structure characterized by that. The pile-column connection structure according to claim 1 , wherein a base plate is provided on a column base of the steel column, and a center hole is formed in the base plate. A method for joining a pile and a column joined by the joining structure according to claim 1 or 2,
A PHC pile with a bonded steel pipe fixed to the top end plate in advance is buried in the ground, and then a steel column is built and the column base is temporarily inserted into the bonded steel pipe, and concrete is cast into the bonded steel pipe. Filling,
A pile-column joining method characterized by using a cross-girder-shaped support frame as a temporary jig for positioning and temporarily supporting a steel column when building a steel column.

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