JP2004211479A - Connection part structure for structure of nonuniform section using prestressed concrete well - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide connection part structure for a structure of nonuniform section using a low-cost prestressed concrete well, provided with sufficient yield strength against bending moment and shearing stress and capable of supporting large load applied in a center axial direction. <P>SOLUTION: This connection part structure is provided with a rigid reinforcing ring body 16 fixed to the opening part edge of a long cylindrical prestresed concrete well structure 11 with a plurality of short cylindrical bodies 13 connected in the center axial direction and integrated, and an axially opposed part arranged on the inner peripheral side of the prestressed concrete well structure 11. Cast-in-place concrete is placed as far as the position of the axial opposed part inside the prestressed concrete well structure 11. A concrete column body 12 formed of the cast-in-place concrete in the form of projecting from the end part of the prestressed concrete structure 11 is thereby integrated with the prestressed concrete well structure 11. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a PC well and a PC well of a variable cross-sectional structure, that is, a structure including a plurality of portions having different cross-sectional shapes, such as a structure combining a PC well structure and a concrete pile or a concrete pillar. The present invention relates to a connection structure of a variable cross-section structure using a PC well for connecting portions having different cross-sectional shapes.
[0002]
[Prior art]
Conventionally, a PC well structure by a PC well method has been used as a foundation for a pier or the like.
[0003]
This PC well structure is laid down while press-fitting a plurality of short cylinders 1, 1... Made of precast concrete, and as shown in FIG. 3 and a short cylinder 1, 1,... Connected to the ground portion to form a pile vent pier type in which the foundation 3 and the pier 4 are integrated, and the entire length of the well structure along the central axis direction. A PC steel material is arranged in such a manner that a prestress is applied to the entire structure by tensioning the PC steel material so that a large bending strength is obtained (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-11-152746 (0018 paragraph, 0026 paragraph, etc.)
[0005]
[Problems to be solved by the invention]
However, in the conventional technique as described above, the joining between the short cylinders has a structure in which the joining surfaces are directly abutted with each other, and the production accuracy of the joining end face of the short cylinder needs to be extremely high. There is a problem in that the cost of manufacturing the cylindrical body is high, and when the entire length of the foundation and the pier is constructed by the PC well method, it becomes very expensive.
[0006]
On the other hand, in order to construct a concrete column with inexpensive cast-in-place concrete or the like on a foundation made of a PC well structure, a large bending moment or shear force acts on the joint between the concrete column and the PC well structure. Concrete columns had to be erected through intermediate members such as slabs and footings.
[0007]
In view of such a state of the prior art, the present invention has a sufficient strength against bending moment and shear stress, can support a large load acting in the central axis direction, and is inexpensively provided with a base made of a PC well structure. It is an object of the present invention to provide a joint structure of a variable cross-section structure using a PC well that enables a concrete column to be joined to a concrete column.
[0008]
[Means for Solving the Problems]
To solve the conventional problems as described above and to achieve the intended object, the invention of claim 1 is a long tubular PC well structure in which a plurality of short cylinders are connected in a central axis direction to be integrated. A rigid ring fixed to the edge of the opening of the PC well structure; and an axial counterpart disposed on the inner peripheral side of the PC well structure. The cast-in-place concrete column having a shape protruding from the end of the PC well structure is integrated with the PC well structure by being driven to the position of the direction opposing portion.
[0009]
With such a configuration, it is possible to appropriately counter hoop tension acting due to bending moment or shear stress and to support a large load. Bridge piers and the like made of concrete pillars can be connected, and structures such as piers can be constructed at low cost.
[0010]
According to a second aspect of the present invention, in addition to the configuration of the first aspect, the reinforcing ring body has a U-shaped cross section that is continuous in a circumferential direction.
[0011]
With this configuration, the joint between the PC well structure and the concrete pillar can be suitably reinforced.
[0012]
According to a third aspect of the present invention, in addition to the configuration of the first aspect, the reinforcing ring body is a steel blade for sinking the PC well structure into the ground.
[0013]
With this configuration, the joint between the PC well structure and the concrete pile can be suitably reinforced.
[0014]
According to a fourth aspect of the present invention, in addition to the configuration of the first, second or third aspect, the concrete column has a flange-shaped enlarged portion on an outer periphery thereof, and the axially opposed portion has an end face of the enlarged portion. It is characterized by having a contacting step.
[0015]
With such a configuration, it is possible to appropriately oppose a load acting in the central axis direction.
[0016]
The invention of claim 5 is characterized in that the axial center opposing portion has a concave portion on the inner periphery of the PC well structure.
[0017]
With such a configuration, it is possible to appropriately oppose a load acting in the central axis direction.
[0018]
According to a sixth aspect of the present invention, in addition to the configuration of the first, second or third aspect, the axially opposed portion includes a plurality of projecting members projecting toward the center from the inner peripheral surface of the PC well structure. Features.
[0019]
With such a configuration, it is possible to appropriately oppose a load acting in the central axis direction.
[0020]
According to a seventh aspect of the present invention, in addition to the configuration of the sixth aspect, the projecting member is provided so as to project from an inner peripheral surface of a steel plate integrated with an inner peripheral surface of the PC well structure.
[0021]
With such a configuration, the load acting in the direction of the central axis can be suitably opposed, and the bending strength of the short cylinder can be improved by the steel plate.
[0022]
The invention according to claim 8 is, in addition to the configuration according to claim 1, 2, or 3, in which the axial center opposing portion is integrated with the inner peripheral surface of the PC well structure, and a circle is formed on the inner peripheral surface of the steel plate. A rib continuously projecting in the circumferential direction.
[0023]
With such a configuration, the load acting in the direction of the central axis can be suitably opposed, and the bending strength of the short cylinder can be improved by the steel plate.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of a joint structure of a variable cross-section structure using a PC well according to the present invention will be described with reference to the drawings. The same parts as those in the above-described conventional example are denoted by the same reference numerals, and description thereof will be omitted.
[0025]
FIG. 1 shows a pier using the joint structure according to the present invention, wherein reference numeral 10 is a pier, and 2 is ground.
[0026]
The pier 10 is a variable cross-section structure in which a base portion made of a PC well structure 11 laid in the ground and a pier portion made of a concrete column 12 protruding from the upper edge of the PC well structure 11 are integrated. It is formed in a one-pillar-one-pile format.
[0027]
Here, the variable cross-section structure refers to a structure including a plurality of portions having different cross-sectional shapes, and the pier 10 includes a PC well structure 11 and a concrete column 12 having a different cross-sectional shape from the PC well structure 11. And a variable cross-sectional structure using a PC well composed of
[0028]
The PC well structure 11 is formed in a long cylindrical shape in which a plurality of short cylinders 13, 13,... Are connected in a central axis direction to be integrated, and a PC steel material is provided on the peripheral wall over the entire length in the central axis direction. The PC well structure 11 is inserted and penetrated, thereby prestressing the entire PC well structure 11.
[0029]
The concrete column 12 is integrated with the upper end of the PC well structure 11 via the joint structure according to the present invention.
[0030]
This joint structure includes a rigid reinforcing ring body 16 fixed to the edge of the upper opening of the PC well structure 11 and an axial counterpart disposed on the inner periphery of the PC well structure. .
[0031]
The axially opposed portion is formed by making the inner diameter of the short cylindrical body (hereinafter referred to as the upper short cylindrical body) 13a forming the uppermost step of the PC well structure 11 smaller than the inner diameter of the connecting short cylindrical body 13b. A step 15 is formed at the joint between the bodies 13a and 13b, and the concrete column 12 is supported on the step 15 in the vertical direction, that is, in the center axis direction.
[0032]
As shown in FIG. 2, the reinforcing ring body 16 has a shape in which a U-shaped cross section opened toward the center of the shaft is continuous in the circumferential direction.
[0033]
The concrete columnar body 12 is formed into a columnar shape projecting from the upper end of the PC well structure 11 by casting cast-in-place concrete in a mold formed so as to be continuous with the internal space 11a of the PC well structure 11. Is done.
[0034]
Also, the concrete column 12 is integrated with the PC well structure 11 by casting (filling) the cast-in-place concrete to the position where the axial opposing portion inside the PC well structure is arranged, It is designed to resist vertical stress.
[0035]
The concrete column 12 has a reinforcing bar structure in which a reinforcing bar (not shown) is disposed.
[0036]
At the joint between the PC well structure 11 and the concrete column 12, when a bending moment or a shearing force is applied, a horizontal pressure acts in the radial direction of the portion, and a local hoop is applied to the side wall of the cylindrical structure. Although tension, that is, a tensile force in the circumferential direction acts, the rigidity of the peripheral wall of the PC well structure is improved by the reinforcement with the reinforcing ring body 16, and sufficient strength is provided against such local hoop tension. .
[0037]
Also, by casting (filling) the cast-in-place concrete to the position of the axially opposed portion, an enlarged diameter portion 17 is formed on the outer peripheral portion of the concrete column 12, and the end face of the enlarged diameter portion 17 is formed in the axial direction. It is supported by the step portion 15 of the opposing portion, and can oppose a vertical or axial stress acting on the connecting portion.
[0038]
Incidentally, the axial opposing portion can be formed as shown below by changing the short upper end cylindrical body in addition to the step portion of the above-described embodiment. Further, the upper short cylindrical body 13a is formed in the same manner as the other short cylindrical bodies, and the inner peripheral surface of the upper short cylindrical body 13 is used as an axial opposing portion so as to oppose the stress acting in the central axis direction by friction or the like. You may.
[0039]
In the axially opposed portion shown in FIG. 3, concave portions 18, 18... Are provided on the inner peripheral portion of the upper short cylindrical body 13a, and cast-in-place concrete is cast to the position of the axially opposed portion having the concave portions 18, 18. By filling, the cast-in-place concrete is filled in the concave portion 18 so as to be able to resist the stress in the axial direction.
[0040]
In the axially opposed portion shown in FIG. 4, a rod-shaped projecting member 19 is provided on the inner peripheral portion of the upper short cylindrical body 13a so as to project toward the axis center, and the cast-in-place concrete is driven to the position of the axially opposed portion. By being provided (filled), the protruding member 19 is embedded in the concrete columnar body 12, so that it is possible to oppose the stress acting in the central axis direction.
[0041]
In addition, mounting members 20, 20... For mounting the protruding members are provided on the inner peripheral portion of the upper short cylindrical body 13a by insert molding, and the ends of the protruding members 19 are press-fitted into the mounting members 20 or FIG. It is designed to be attached by screwing as shown in FIG.
[0042]
Further, as shown in FIG. 6, the projecting member 19 has a steel plate 21 integrated with the inner peripheral portion of the upper short cylindrical body 13a, and is protruded from the inner surface of the steel plate 21 by stud welding or the like. Is also good.
[0043]
The axially opposed portion shown in FIG. 7 integrates a steel plate 23 having circumferentially continuous ribs 22, 22,... On the inner surface with the inner portion of the upper-end short cylindrical body 13a, and casts the cast-in-place concrete into the axially opposed portion. Is formed into a shape in which the ribs 22, 22 ... bite into the outer peripheral portion of the concrete columnar body 12 so as to be able to oppose the stress acting in the central axis direction.
[0044]
In the above-described embodiment, an example in which the base portion made of the PC well structure and the cast-in-place concrete column are connected using the connection portion structure according to the present invention has been described. As shown, the joint structure according to the present invention is provided at the lower end of a PC well structure, the upper half of a foundation pile 30 is a PC well structure 31, and the lower half is a cast-in-place concrete pile 32 which is a concrete column. It can be.
[0045]
8A is a cross-sectional view illustrating a state of the stratum of the ground where the foundation pile 30 is laid, and FIG. 8B is a graph illustrating the ground strength (N value) of the ground where the foundation pile 30 is laid. In the ground 2, a support layer made of gravel or the like having a high ground strength (N value) is formed at a deep position in the ground 2, and a clay having a relatively low ground strength is formed between the support layer and the surface of the ground. Layers such as sand and silt are laminated.
[0046]
In this case, the reinforcing ring is a steel cutting edge 33 for sinking the PC well structure 31 into the ground.
[0047]
Further, in this joint structure, a short cylindrical body 34 (hereinafter, referred to as a lower short cylindrical body) constituting the lowermost stage of the PC well structure 31 is combined with the upper short cylindrical body 13a shown in FIGS. By similarly forming, it is possible to provide various forms of axial opposing portions as shown in FIGS. 9 to 13. The same parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0048]
Further, the lower short cylinder may be formed in the same manner as the other short cylinders, and the inner peripheral surface of the lower short cylinder 34 may be used as an axial opposing portion to oppose the stress acting in the central axis direction by friction. Good.
[0049]
【The invention's effect】
As described above, the joint structure of the variable cross-section structure using the PC well according to the present invention suitably counters local hoop tension acting on the peripheral wall of the PC well structure due to bending moment or shear stress, and Because it is possible to support a strong load, it is possible to directly connect a pier made of cast-in-place concrete pillars to a foundation made of a PC well structure, without using intermediate members such as slabs and footings. In addition, a structure such as a pier can be constructed at low cost by reducing the number of expensive short cylinders.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a one-pillar-one-pile type pier using a joint structure of a variable cross-section structure using a PC well according to the present invention.
2A is a perspective view showing a reinforcing ring body in FIG. 1, and FIG. 2B is a partially enlarged sectional view taken along line AA.
FIG. 3 is a cross-sectional view showing another example of the coupling section in FIG.
FIG. 4 is a sectional view showing another example of the above.
5 is a cross-sectional view showing an example of a mounting state of a protruding member in FIG.
FIG. 6 is a cross-sectional view showing another example of the coupling portion in FIG.
FIG. 7 is a sectional view showing another example of the above.
FIG. 8A is a cross-sectional view showing a stratum state of a ground on which a foundation pile using a joint structure of a variable cross-section structure using a PC well according to the present invention is laid, and FIG. FIG. 5C is a graph showing (N value), and FIG. 5C is a cross-sectional view showing a state where the foundation pile is laid down.
FIG. 9 is a cross-sectional view showing a coupling portion of the above.
FIG. 10 is a sectional view showing another example of the above.
FIG. 11 is a sectional view showing another example of the above.
FIG. 12 is a sectional view showing another example of the above.
FIG. 13 is a sectional view showing another example of the above.
FIG. 14 is a front view showing a pier using a conventional PC well structure.
[Explanation of symbols]
10 Bridge Pier 11 PC Well Structure 12 Concrete Column 13 Short Cylindrical Body 15 Step 16 Reinforcement Ring 17 Large Diameter 18 Recess 19 Projecting Member 20 Mounting Member 21 Steel Plate 22 Rib 23 Steel Plate

Claims (8)

A reinforcing ring body having rigidity fixed to an opening edge of a long tubular PC well structure in which a plurality of short cylindrical bodies are connected in a central axis direction and integrated, and an inner peripheral side of the PC well structure; An axially opposed portion disposed, and casting a cast-in-place concrete to the position of the axially opposed portion inside the PC well structure, thereby forming a location protruding from an end of the PC well structure. A joint structure of a variable cross-section structure using a PC well, wherein a cast concrete column is integrated with the PC well structure. The joint structure according to claim 1, wherein the U-shaped cross section of the reinforcing ring body is continuous in the circumferential direction. The joint structure according to claim 1, wherein the reinforcing ring body is a steel cutting edge for sinking the PC well structure into the ground. 4. The PC well according to claim 1, wherein the concrete column has a flange-shaped enlarged portion on the outer periphery thereof, and the axially opposed portion has a step with which an end face of the enlarged portion abuts. 5. The joint structure of a variable cross-section structure using The joint structure of a variable cross-section structure using a PC well according to claim 1, 2 or 3, wherein the axial direction opposing portion has a recess on the inner periphery of the PC well structure. The variable cross-section structure using a PC well according to claim 1, 2 or 3, wherein the axial opposing portion includes a plurality of rod-shaped protruding members protruding toward the center from the inner peripheral surface of the PC well structure. Joint structure. 7. The structure of claim 6, wherein the protruding member protrudes from an inner peripheral surface of a steel plate integrated with an inner peripheral surface of the PC well structure. The axial direction opposing portion includes a steel plate integrated with the inner peripheral surface of the PC well structure, and a rib continuously projecting in the circumferential direction on the inner peripheral surface of the steel plate. 4. A joint structure of a variable cross-section structure using the PC well according to 3.

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