JP3796605B2 - Joint structure of variable cross-section structure using PC well - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a PC well and a PC well of a structure having a plurality of parts having different cross-sectional shapes, such as a variable cross-section structure, that is, a structure in which a PC well structure and a concrete pile or a concrete column are combined. And relates to a joint structure of a variable cross-section structure using a PC well for joining portions having different cross-sectional shapes.
[0002]
[Prior art]
Conventionally, a PC well structure by a PC well construction method is used as a foundation of a bridge pier or the like.
[0003]
In this PC well structure, a plurality of short cylindrical bodies 1, 1... Made of precast concrete are sunk while being press-fitted, and as shown in FIG. 3, and a short cylindrical body 1, 1... Are connected to the ground portion to form a pile bent pier type in which the base 3 and the pier 4 are integrated, and the well structure has a total length in the central axis direction. The PC steel material is disposed and tensioned to impart prestress to the entire structure so that a large bending strength can be obtained (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP 11-152746 A (paragraphs 0018, 0026, etc.)
[0005]
[Problems to be solved by the invention]
However, in the conventional technology as described above, the joining between the short cylinders has a structure in which the joining surfaces are directly abutted, and the manufacturing accuracy of the joining end face of the short cylinder needs to be very high. The production of the cylindrical body is expensive, and if the entire length of the foundation and the pier is constructed by the PC well method, there is a problem that it becomes very expensive.
[0006]
On the other hand, in order to construct a concrete column by cheap cast-in-place concrete etc. on a foundation made of a PC well structure, a large bending moment or shearing force acts on the joint portion between the concrete column and the PC well structure. Concrete pillars had to be erected through intermediate members such as slabs and footings.
[0007]
In view of the state of the prior art as described above, the present invention has a sufficient resistance to bending moment and shear stress, can support a large load acting in the direction of the central axis, and is made of a PC well structure at low cost. 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 columnar body to be bonded to a wall.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned conventional problems and achieve the intended object, the invention of claim 1 is a long cylindrical PC well structure in which a plurality of short cylinders are integrated in a central axis direction. A rigid reinforcing ring body fixed to the edge of the opening and having a U-shaped cross-section continuous in the circumferential direction, and an axially opposed portion disposed on the inner peripheral side of the PC well structure The cast-in-place concrete columnar body having a shape protruding from the end of the PC-well structure is formed by casting cast-in concrete up to the position of the axially opposed portion inside the PC-well structure. It is characterized by being integrated with.
[0009]
By configuring in this way, it is possible to suitably resist a hoop tension acting by a bending moment or a shear stress and to support a strong load. Bridge piers and the like made of concrete pillars can be connected, structures such as piers can be constructed at low cost, and the joint between the PC well structure and the concrete pillars can be suitably reinforced. .
[0010]
The invention of claim 2 is fixed to the edge of the opening of a long cylindrical PC well structure in which a plurality of short cylindrical bodies are integrated in a central axis direction, and the PC well structure is submerged in the ground. A rigid ring body having a steel blade edge and an axially opposed portion disposed on the inner peripheral side of the PC well structure, and cast-in-place concrete inside the PC well structure. The cast-in-place concrete columnar body 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 axially opposed portion.
[0011]
By configuring in this way, it is possible to suitably resist a hoop tension acting by a bending moment or a shear stress and to support a strong load. Bridge piers and the like made of concrete pillars can be connected, structures such as bridge piers can be constructed at low cost, and the joint between the PC well structure and the concrete pile can be suitably reinforced.
[0012]
In addition to the configuration of the first or second aspect, the concrete columnar body includes a flange-shaped enlarged diameter portion on the outer periphery thereof, and the end face of the enlarged diameter portion abuts the axially opposing portion. A step portion is provided.
[0013]
By comprising in this way, it can oppose suitably for the load which acts on a central-axis direction.
[0014]
The invention of claim 4 is characterized in that, in addition to the configuration of claim 1 or 2, the axially opposing portion is provided with a recess in the inner periphery of the PC well structure.
[0015]
By comprising in this way, it can oppose suitably for the load which acts on a central-axis direction.
[0016]
The invention of claim 5 is characterized in that, in addition to the configuration of claim 1 or 2, the axially opposed portion includes a plurality of projecting members that project from the inner peripheral surface of the PC well structure toward the center. To do.
[0017]
By comprising in this way, it can oppose suitably for the load which acts on a central-axis direction.
[0018]
The invention of claim 6 is characterized in that, in addition to the structure of claim 5, the projecting member protrudes from the inner peripheral surface of the steel plate integrated with the inner peripheral surface of the PC well structure.
[0019]
By comprising in this way, while being able to oppose suitably the load which acts on a central-axis direction, the bending strength of a short cylindrical body can be improved with a steel plate.
[0020]
In addition to the structure of claim 1 or 2, the invention of claim 7 is a steel plate in which the axial direction counter part is integrated with the inner peripheral surface of the PC well structure, and the inner peripheral surface of the steel plate in the circumferential direction. And a rib projecting continuously.
[0021]
With such a configuration, it is possible to suitably counter the load acting in the central axis direction, and it is possible to improve the bending strength of the short cylindrical body by the steel plate.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the joint structure of the variable cross-section structure using the PC well according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the part same as the prior art example mentioned above, and description is abbreviate | omitted.
[0023]
FIG. 1 shows a bridge pier using a connecting portion structure according to the present invention, where reference numeral 10 denotes a pier and 2 denotes a ground.
[0024]
The bridge pier 10 is a variable cross-section structure in which a base portion made of a PC well structure 11 submerged in the ground and a bridge pier portion made of a concrete columnar body 12 protruding from the upper edge of the PC well structure 11 are integrated. It is formed in the form of one pillar and one pile.
[0025]
Here, the variable cross-section structure refers to a structure composed of a plurality of parts having different cross-sectional shapes, and the pier 10 includes a PC well structure 11 and a concrete columnar body 12 having a cross-sectional shape different from that of the PC well structure 11. This is a variable cross-sectional structure using a PC well composed of
[0026]
The PC well structure 11 is formed in a long cylindrical shape in which a plurality of short cylindrical bodies 13, 13... Are integrated in a central axis direction, and a PC steel material is formed on the peripheral wall over the entire length in the central axis direction. The prestress is given to the whole PC well structure 11 by being inserted and tensioning the PC steel material.
[0027]
The concrete columnar body 12 is integrated with the upper end portion of the PC well structure 11 via the joint structure according to the present invention.
[0028]
This coupling portion structure includes a reinforcing ring body 16 having rigidity fixed to the edge of the upper end opening of the PC well structure 11, and an axially opposing portion disposed on the inner peripheral portion of the PC well structure. .
[0029]
The axially opposing portion is formed by making the inner diameter of a short cylindrical body (hereinafter referred to as an upper short cylindrical body) 13a that forms the uppermost step portion of the PC well structure 11 smaller than the inner diameter of the connecting short cylinder 13b. A step portion 15 is formed at a joint portion between the bodies 13a and 13b, and the concrete columnar body 12 is supported on the step portion 15 in the vertical direction, that is, in the central axis direction.
[0030]
As shown in FIG. 2, the reinforcing ring body 16 has a shape in which a U-shaped cross section opened toward the axial center side is continuous in the circumferential direction.
[0031]
The concrete columnar body 12 is formed in a columnar shape protruding from the upper end of the PC well structure 11 by placing cast-in-place concrete in a mold formed to be continuous with the internal space 11a of the PC well structure 11. Is done.
[0032]
In addition, the concrete columnar body 12 is integrated with the PC well structure 11 by placing (filling) the on-site concrete up to the position where the axially opposing portion inside the PC well structure is disposed, It can resist the stress applied in the vertical direction.
[0033]
The concrete columnar body 12 has a reinforcing bar structure in which a reinforcing bar rod (not shown) is arranged.
[0034]
When a bending moment or a shearing force acts on the joint portion between the PC well structure 11 and the concrete columnar body 12, a horizontal pressure acts in the radial direction of the portion, and a local hoop is formed on the side wall of the cylindrical structure. Although tension, that is, circumferential tensile force acts, the reinforcement of the reinforcing ring body 16 improves the rigidity of the peripheral wall of the PC well structure, and has sufficient strength against such local hoop tension. .
[0035]
In addition, by placing (filling) cast-in-place concrete to the position of the axially opposed portion, a diameter-expanded portion 17 is formed on the outer peripheral portion of the concrete columnar body 12, and the end surface of the diameter-expanded portion 17 is axial. It is supported by the stepped portion 15 of the opposing portion, and can resist the stress in the vertical direction, that is, the axial direction acting on the connecting portion.
[0036]
The axially opposing portion can be as shown below by changing the upper short 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 resist stress acting in the central axial direction due to friction or the like. May be.
[0037]
3, recesses 18, 18... Are provided in the inner peripheral portion of the upper short cylindrical body 13a, and cast-in-place concrete is cast to the position of the axial facing portion having the recesses 18, 18. By filling), the concave portion 18 is filled with cast-in-place concrete so that it can resist the stress in the axial direction.
[0038]
Further, in the axially opposed portion shown in FIG. 4, a rod-shaped protruding member 19 is projected toward the axial center on the inner peripheral portion of the upper short cylindrical body 13a, and cast-in-place concrete is struck to the position of the axially opposed portion. By providing (filling), the projecting member 19 is embedded in the concrete columnar body 12 and can resist the stress acting in the central axis direction.
[0039]
.. Are attached to the inner peripheral portion of the upper short cylindrical body 13a by insert molding. The end of the protruding member 19 is press-fitted into the mounting member 20 or FIG. It attaches by screwing like this.
[0040]
Further, as shown in FIG. 6, the protruding member 19 has a steel plate 21 integrated with the inner peripheral portion of the upper short cylindrical body 13a, and is projected on the inner surface of the steel plate 21 by stud welding or the like. Also good.
[0041]
The axial direction opposing part shown in FIG. 7 integrates the steel plate 23 provided with the ribs 22,22 ... which continued in the circumferential direction on the inner surface with the inner side part of the upper end short cylindrical body 13a, and casts in place concrete in the axial direction opposing part. When it is driven to the position, the ribs 22, 22... Bite into the outer periphery of the concrete columnar body 12, and can resist the stress acting in the central axis direction.
[0042]
In the above-described embodiment, the example in which the foundation portion made of the PC well structure and the concrete column of cast-in-place concrete are coupled using the coupling 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 the PC well structure, the upper half of the foundation pile 30 is the PC well structure 31, and the lower half is a cast-in-place concrete pile 32 that is a concrete columnar body. It can be.
[0043]
8A is a cross-sectional view showing the state of the ground layer where the foundation pile 30 is submerged, and FIG. 8B is a graph showing the ground strength (N value) of the ground where the foundation pile 30 is submerged. The ground 2 is a clay having a relatively low ground strength between the support layer and the ground surface, in which a support layer made of gravel or the like having a high ground strength (N value) is formed at a deep position of the ground 2. Layers such as sand and silt are stacked.
[0044]
In this case, the reinforcing ring body is a steel blade 33 for allowing the PC well structure 31 to sink into the ground.
[0045]
Further, in this connecting portion 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 replaced with the upper short cylindrical body 13a shown in FIGS. By forming similarly, as shown in FIGS. 9-13, various forms of axial direction opposing parts can be provided. In addition, the same code | symbol is attached | subjected to the part same as the above-mentioned Example, and description is abbreviate | omitted.
[0046]
Further, the lower end short cylindrical body is formed in the same manner as the other short cylindrical bodies, and the inner peripheral surface of the lower end short cylindrical body 34 is used as an axially opposing portion so as to resist the stress acting in the central axis direction by friction. Good.
[0047]
【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 Since it is possible to support a strong load, it is possible to connect a bridge pier made of a cast-in-place concrete column directly 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 bridge pier can be constructed at a low cost by reducing the number of expensive short cylinders.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a pier of one pillar and one pile type 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 cross-sectional view taken along line AA in FIG.
FIG. 3 is a cross-sectional view showing another example of a coupling portion in FIG. 1;
FIG. 4 is a cross-sectional view showing another example of the above.
5 is a cross-sectional view showing an example of a mounting state of the protruding member in FIG. 4. FIG.
6 is a cross-sectional view showing another example of the connecting portion in FIG. 1. FIG.
FIG. 7 is a cross-sectional view showing another example of the above.
FIG. 8A is a cross-sectional view showing a formation state of a ground where a foundation pile using a joint structure of a variable cross-section structure using a PC well according to the present invention is submerged, and FIG. The graph which shows (N value), (c) is sectional drawing which shows the state by which the foundation pile was laid.
FIG. 9 is a cross-sectional view showing the coupling portion of the above.
FIG. 10 is a cross-sectional view showing another example of the above.
FIG. 11 is a cross-sectional view showing another example of the above.
FIG. 12 is a cross-sectional view showing another example of the above.
FIG. 13 is a cross-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]
DESCRIPTION OF SYMBOLS 10 Bridge pier 11 PC well structure 12 Concrete columnar body 13 Short cylindrical body 15 Step part 16 Reinforcement ring body 17 Expanded diameter part 18 Recessed part 19 Protruding member 20 Mounting member 21 Steel plate 22 Rib 23 Steel plate

Claims (7)

  Reinforcement having rigidity that is fixed to the opening edge of a long cylindrical PC well structure in which a plurality of short cylinders are integrated in the central axis direction, and whose U-shaped cross section is continuous in the circumferential direction. A ring body and an axially opposed portion disposed on the inner peripheral side of the PC well structure, and placing cast-in-place concrete to the position of the axially opposed portion inside the PC well structure, A joint structure of a variable cross-section structure using a PC well, wherein a cast-in-place concrete columnar body protruding from an end of the PC well structure is integrated with the PC well structure.   A steel blade is used to sink the PC well structure into the ground, and is fixed to the opening edge of the long cylindrical PC well structure that integrates a plurality of short cylinders in the direction of the central axis. A reinforcing ring body having rigidity and an axially opposed portion arranged on the inner peripheral side of the PC well structure, and cast-in-place concrete to the position of the axially opposed portion inside the PC well structure A cast-in-place concrete structure using a PC well, wherein a cast-in-place concrete columnar body having a shape protruding from an end of the PC well structure is integrated with the PC well structure. Bonding part structure.   3. The PC well according to claim 1, wherein the concrete columnar body includes a flange-shaped enlarged diameter portion on an outer periphery thereof, and the axially opposing portion includes a step portion with which an end face of the enlarged diameter portion abuts. The joint structure of the modified cross-section structure.   The joint part structure of a variable cross-section structure using a PC well according to claim 1 or 2, wherein the axially opposing part is provided with a recess in the inner periphery of the PC well structure.   The joint portion of the variable cross-section structure using the PC well according to claim 1 or 2, wherein the axial direction opposing portion includes a plurality of rod-like projecting members projecting toward the center from the inner peripheral surface of the PC well structure. Construction.   6. The joint structure of a variable cross-section structure using a PC well according to claim 5, wherein the protruding member protrudes from the inner peripheral surface of the steel plate integrated with the inner peripheral surface of the PC well structure.   The axially opposing portion includes a steel plate integrated with the inner peripheral surface of the PC well structure, and a rib that continuously protrudes in the circumferential direction on the inner peripheral surface of the steel plate. The joint structure of the variable cross-section structure using the described PC well.

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