JP6474231B2 - Arena - Google Patents

Description

  The present invention relates to an arena.

In a concert hall or the like, when a large audience hops on the floor slab in accordance with music, the vibration of the floor slab is transmitted to the ground due to the large number of vibrations generated by the hopping of the audience. Depending on the ground properties, there is a problem that vibration transmitted to the ground diffuses outside the structure such as a concert hall and vibrates surrounding buildings.
For example, Patent Document 1 discloses a technique for reducing vibration generated by large-scale excitation so as not to diffuse outside the structure.

  In Patent Document 1, a floor slab serving as a vibration generation source is cut off from a structure and a lower ground, and is supported by a pile that reaches the support ground. Furthermore, the pile is surrounded by the cylindrical material, and the vibration propagating from the pile to the surrounding ground is blocked. Thereby, even if the floor slab becomes a vibration generation source due to large-scale vibration or the like, vibrations diffusing from the floor slab to the surrounding ground can be reduced.

JP 2007-107208 A

  However, the technique of Patent Document 1 is a technique in the case where there is no passenger seat portion surrounding a floor slab that is a vibration generation source.

  In view of the above fact, an object of the present invention is to reduce vibration generated in an arena in which a passenger seat portion surrounds a floor slab of a field portion.

The arena according to the first aspect of the invention is an arena including a field portion and a passenger seat portion surrounding the field portion, and supports the floor slab of the field portion in a state of floating from the ground surface, and a lower end A cast-in-place pile or a built-up pile support pile whose part is embedded in the support layer of the ground, and a cylinder whose upper end is provided with a gap from the floor slab of the field part, and surrounds the support pile with a gap And a rib as a buckling prevention means that is discretely provided in the depth direction on the inner peripheral surface of the tubular member and prevents buckling of the support pile .

According to invention of Claim 1, the floor slab of a field part is supported by the support pile in the state which floated from the ground surface. Moreover, the clearance gap is provided between the support pile and the ground which support the floor slab of a field part with a cylinder material.
Thereby, the vibration which generate | occur | produced in the field part is propagated to a support layer through a support pile, and the vibration transmitted to the exterior of an arena via a ground can be suppressed. In addition, loud sounds generated outside the field are blocked at the passenger seat and are not easily transmitted to the outside.

One aspect of the invention is characterized in that buckling prevention means for preventing buckling of the support pile is provided on the inner peripheral surface of the cylindrical member or the outer peripheral surface of the support pile.

According to one aspect of the invention , buckling of the support pile is suppressed by the buckling prevention means. Thereby, even if it lengthens a support pile, the diameter of a support pile can be determined, without considering the yield strength reduction by buckling with respect to a vertical load.
Moreover, since buckling is suppressed, the diameter of the support pile can be made smaller than when there is no buckling prevention means.

In one aspect of the invention, the support pile is a cast-in-place pile or an existing pile, and the buckling prevention means is a rib provided discretely in the depth direction on the inner peripheral surface of the tubular material. It is characterized by.

According to one aspect of the invention, since the buckling of the support pile is suppressed by the rib provided on the inner peripheral surface of the cylindrical member, no rib is required on the support pile side. At this time, since the ribs are provided discretely in the depth direction, it is possible to effectively secure a gap between the tubular material and the support pile. Moreover, as a support pile, either a cast-in-place pile or an existing pile can be used.

  Since the present invention is configured as described above, it is possible to reduce the vibration generated in the arena in which the passenger seat portion surrounds the floor slab of the field portion.

It is a vertical sectional view showing the basic composition of the arena according to the first embodiment of the present invention. (A)-(C) are vertical sectional views which show the structure of the double pipe pile provided under the floor slab of the field part of the arena which concerns on 1st Embodiment of this invention. (A) is a vertical sectional view showing a configuration of a double pipe pile provided under a floor slab of a field portion of an arena according to a second embodiment of the present invention, and (B) is a partially enlarged view thereof. . (A) is a top view which shows the structure of the double pipe pile provided under the floor slab of the field part of the arena concerning 3rd Embodiment of this invention, (B) is the perpendicular | vertical fragmentary sectional view. . (A)-(C) are vertical sectional views for demonstrating the construction method of the double pipe pile which concerns on 3rd Embodiment of this invention. (A) is a horizontal sectional view which shows the structure of the double pipe pile provided under the floor slab of the field part of the arena concerning 4th Embodiment of this invention, (B) is the vertical fragmentary sectional view. is there. (A)-(C) are all horizontal sectional drawings for demonstrating the construction method of the double pipe pile which concerns on 4th Embodiment of this invention. (A) is a perspective view which shows the form for support piles of the double pipe pile concerning 4th Embodiment of this invention, (B) is a perspective view which shows the vertical cross section.

(First embodiment)
The arena 10 according to the first embodiment will be described with reference to FIGS. 1 and 2A to 2C. Here, FIG. 1 is a vertical sectional view of the arena 10, and FIGS. 2A to 2C are sectional views of three types of double pipe piles 21S, 21M, and 21L.

As shown in FIG. 1, the arena 10 includes a field portion 12 and a passenger seat portion 14 surrounding the field portion 12. The field section 12 of the arena 10 is provided with a flat floor slab 16 in which a sports competition or the like is performed in the lateral direction.
A plurality of double pipe piles 21 are provided under the floor slab 16 of the field portion 12. The double pipe pile 21 includes a support pile 20 that supports the floor slab 16 and an outer steel pipe (tubular material) 22 that surrounds the support pile 20.

  The support pile 20 is made of reinforced concrete, and the lower end portion is rooted in the support layer 62 directly below the floor slab 16 and the floor slab 16 is supported by the upper end portion. A distance H1 is provided in the height direction between the ground surface 18 and the floor slab 16, and the support pile 20 supports the floor slab 16 in a floating state. The distance H1 is a height at which the floor slab 16 does not contact the ground surface even when the floor slab 16 vibrates in the vertical direction.

  An outer steel pipe 22 is embedded around the support pile 20. The outer steel pipe 22 is formed of a hollow steel pipe and surrounds the support pile 20 with a gap d1. The outer steel pipe 22 has an upper end located at the same height as the ground surface 18 and a lower end reaching the gravel layer 60 directly below the floor slab 16. In addition, in this embodiment, it was set as the structure laminated | stacked in order of the surface layer ground 64, the general intermediate | middle ground layer 63, the gravel layer 60, and the support layer 62 from the top for convenience.

The gap d1 between the outer peripheral surface 20G of the support pile 20 and the inner peripheral surface 20N of the outer steel pipe 22 is set to a size larger than the amplitude at the time of vibration of the support pile 20, and the vibration of the support pile 20 is generated in the outer steel pipe 22. Not transmitted. Thereby, transmission of the vibration to the surface layer ground 64 is suppressed.
On the other hand, when the support pile 20 receives a lateral load and the support pile 20 moves sideways, the support pile 20 contacts the inner peripheral surface of the outer steel pipe 22. Thereby, the further deformation | transformation of the support pile 20 is suppressed.

  By adopting this configuration, vibration generated in the floor slab 16 of the field portion 12 is propagated to the support layer through the support pile 20. That is, the edge of the floor slab 16 and the surface ground 64 is cut, and the support pile 20 and the ground (the surface ground 64, the intermediate ground 63) are also edged, so that the vibration generated in the floor slab 16 It is possible to suppress vibrations from being transmitted to the outside of the arena 10.

Further, the loud sound generated outside the field portion 12 is blocked by the passenger seat portion 14 and is difficult to be transmitted to the outside.
It is desirable that the floor slab 16 and the floor slab 28 of the passenger seat 14 of the arena 10 are also cut at the edge cutting part 68. Thereby, propagation of the vibration generated in the floor slab 16 of the field portion 12 to the outside can be further suppressed.

A double pipe pile 25 is provided under the floor slab 28 of the passenger seat section 14 surrounding the field section 12 of the arena 10. The double pipe pile 25 includes a support pile 24 and an outer steel pipe 26.
The support pile 24 is made of reinforced concrete, and a lower end portion is embedded in a support layer 62 directly below the floor slab 28, and the upper end supports the passenger seat portion 14 including the floor slab 28 and the roof frame portion 11. doing. The floor slab 28 of the passenger seat part 14 is supported by the support pile 24 in a state of being lifted from the ground surface 18 by the height H1. The height H1 is set so as not to contact the ground surface 18 even if the floor slab 28 of the passenger seat portion 14 vibrates.

  The outer steel pipe 26 surrounds the support pile 24 and is embedded with a gap d2 from the support pile 24. The outer steel pipe 26 has an upper end located at the same height as the ground surface 18, and a lower end reaching the gravel layer 60 located below the surface ground 64.

A gap d2 between the outer peripheral surface 24G of the support pile 24 and the inner peripheral surface 26N of the outer steel pipe 26 is larger than the amplitude during vibration of the support pile 24, and the vibration of the support pile 24 is caused in the outer steel pipe 26. Not transmitted. Thereby, transmission of the vibration to the surface layer ground 64 is suppressed.
On the other hand, when the support pile 24 receives a lateral load, the support pile 24 moves to the side, and the support pile 24 contacts the inner peripheral surface of the outer steel pipe 26. Thereby, the further deformation | transformation of the support pile 24 is suppressed.

By setting it as this structure, the contact with the support pile 24 and the ground (surface layer ground 64, intermediate | middle layer 63) is prevented, and it is suppressed that the vibration of the support pile 24 is transmitted to the ground.
Here, each of the support piles 20 and 24 may be a cast-in-place pile or an existing pile. Further, since the floor slab 16 of the field portion 12 has a smaller weight than the passenger seat portion 14 including the floor slab 28 and the roof frame portion 11, the support pile 20 that supports the floor slab 16 of the field portion 12 is provided with the floor slab 28. Is smaller than the support pile 24 that supports the passenger seat portion 14 and the roof frame portion 11.

Here, the basic configuration of the double pipe pile 21 will be described.
In general, as the outer steel pipe 22 of the double pipe pile 21 is embedded in the surface ground 64, the contact between the support pile 20 and the ground (the surface ground 64, the intermediate ground 63) is suppressed. It is known that the vibration reduction effect by the outer steel pipe 22 is great. However, the vibration reduction effect decreases as the distance from the arena 10 increases. For this reason, it is desirable that the optimum length is determined based on the economic relationship, the structure of the arena 10, the arrangement relationship / distance with the surrounding buildings, the relationship with the geology constituting the surface ground 64, and the like.

It demonstrates concretely using three types of double pipe piles 21S, 21M, and 21L from which the length of an outer steel pipe differs. The double pipe pile 25 is the same, and description is abbreviate | omitted.

FIG. 2 (A) shows the configuration of the double pipe pile 21S under conditions that do not require a large vibration reduction effect from the structure of the arena 10, the structure of the surface ground 64, and the like.
Since the double pipe pile 21S may be shallow in the ground depth to be edged by the outer steel pipe 22S, the length L1 of the outer steel pipe 22S may be, for example, the length from the ground surface 18 to the middle of the surface ground 64. Since the outer steel pipe 22S can be shortened, the economic burden is small.

FIG. 2B shows the configuration of the double pipe pile 21M under conditions that require a somewhat large vibration reduction effect from the structure of the arena 10, the structure of the surface ground 64, and the like.
Since the double pipe pile 21M requires a certain depth of the ground to be edged by the outer steel pipe 22M, the length L2 of the outer steel pipe 22M needs to be a length reaching from the ground surface 18 to the lower end of the surface layer ground 64, for example. . As long as the outer steel pipe 22M is lengthened, a vibration reduction effect can be expected.

FIG. 2C shows the structure of the double pipe pile 21L under conditions where a large vibration reduction effect is required from the structure of the arena 10, the structure of the surface ground 64, and the like.
Since the double pipe pile 21L needs a sufficient ground depth to be edged by the outer steel pipe 22L, the length L3 of the outer steel pipe 22L is, for example, a length reaching the gravel layer 60 from the ground surface 18. Since the outer steel pipe 22L is made sufficiently long, a large vibration reduction effect can be expected.

As described above, according to this configuration, the floor slab 16 of the field portion 12 is supported by the support pile 20 in a state of floating from the ground surface 18, and the floor slab 28 of the passenger seat portion 14 is grounded by the support pile 24. It is supported in a state where it floats from the surface 18 at a distance H1.
In addition, a gap d <b> 1 is provided between the outer steel pipe 22 and the support pile 20, and a gap d <b> 2 is provided between the outer steel pipe 26 and the support pile 24. Thereby, the spreading | diffusion to the surface layer ground 64 of the vibration generate | occur | produced in the passenger seat part 14 containing the floor slab 28 and the vibration generate | occur | produced in the floor slab 16 of the passenger seat part 14 can be reduced with the double pipe piles 21 and 25. .

  In addition, in this embodiment, the structure which provided the double pipe pile 21 under the floor slab 16 of the field part 12 and provided the double pipe pile 25 under the floor slab 28 of the passenger seat part 14 was described. However, the present invention is not limited to this. For example, the floor slab 28 of the passenger seat 14 may be a simple support pile from the structure of the arena 10, the structure of the surface layer ground 64, and the like.

(Second Embodiment)
The double pipe pile 38 which concerns on 2nd Embodiment is demonstrated using FIG.
The double pipe pile 38 is different from the double pipe pile 21 described in the first embodiment in that the support pile 20 that supports the floor slab 16 of the field portion 12 is a node pile 32. The difference will be mainly described.
FIG. 3A is a vertical sectional view showing the configuration of the double pipe pile 38 according to the second embodiment of the present invention, and FIG. 3B is a partial enlarged view of FIG.

  As for the joint pile 32, the outer diameter dimension of the pile body part is set to D1, and the joint part (protrusion part) 36 is projected in an annular shape on the outer peripheral surface 32G of the pile body part. The node 36 has an outer dimension of D2, and is provided discretely in the depth direction (length direction) with a predetermined distance H2. Here, the term “discrete” means that a plurality of nodes are arranged away from each other in the depth direction.

A predetermined gap d <b> 3 is provided between the outer peripheral end of the node portion 36 and the inner peripheral surface 34 </ b> N of the outer steel pipe 34. The gap d <b> 3 has a size larger than the amplitude at the time of vibration of the joint pile 32, and the vibration of the joint pile 32 is not transmitted to the outer steel pipe 34. Thereby, transmission of the vibration to the ground (surface ground 64, intermediate ground 63) is suppressed.
On the other hand, when the joint pile 32 receives a lateral load, the joint pile 32 moves sideways, and the joint portion 36 comes into contact with the inner peripheral surface of the outer steel pipe 34. Thereby, the further deformation | transformation of the joint pile 32 is suppressed.

  The joint pile 32 is particularly effective when the pile length is long. That is, when the joint pile 32 is deformed, the joint portion 36 comes into contact with the inner peripheral surface of the outer steel pipe 34, and further deformation is suppressed. Thereby, since the buckling is suppressed by the node portion 36, the buckling can be prevented without increasing the pile diameter more than necessary.

  From an economic point of view, it is desirable to minimize the number of nodes 36 on the premise of ensuring buckling strength, and it is desirable to maximize the distance H2 between the nodes 36. Further, it is desirable to apply a friction reducing agent (slip agent) between the node 36 and the inner surface of the steel pipe as necessary. Thereby, it can suppress that a vertical vibration is transmitted between the joint pile 32 and the outer steel pipe 34. FIG.

  The method for constructing the double-pipe pile 38 is, for example, in the factory, the joint pile 32 is manufactured in advance with reinforced concrete, the joint pile 32 having a predetermined length is transported to the site, and then the excavation hole 66 provided on the site is provided. Furthermore, it is sufficient to add the node pile 32 while inserting it into the outer steel pipe 34 and embed it to a predetermined depth.

As a result, there are merits such as high quality and labor saving at the factory. Further, by using the double pipe pile 38, transmission of vertical vibration is cut off, while a horizontal force during an earthquake is transmitted to the surface layer ground 64 through the outer steel pipe 34 at the node 36.

  By using the double pipe pile 38 described above in place of the double pipe pile 21 described in the first embodiment, even if the pile length of the field portion 12 of the arena 10 is long, the seat 36 is seated by the node portion 36. Since buckling is suppressed, buckling can be prevented without increasing the pile diameter more than necessary.

In addition, in this embodiment, the case where the support pile 20 which supports the floor slab 16 of the field part 12 was used as the joint pile 32 was demonstrated. However, the present invention is not limited to this, and the support pile 24 that supports the passenger seat portion 14 including the floor slab 28 and the roof frame portion 11 may be the joint pile 32, or both may be the joint pile 32.
Other configurations are the same as those in the first embodiment, and a description thereof will be omitted.

(Third embodiment)
The double pipe pile 48 which concerns on 3rd Embodiment is demonstrated using FIG. 4 (A), (B) and FIG. 5 (A)-(C).
The double pipe pile 48 relates to the first embodiment in that a lateral rib (buckling stop) 46 is provided on the inner peripheral surface 44N of the outer steel pipe 44 embedded under the floor slab 16 of the field portion 12. It differs from the double pipe pile 21. The difference will be mainly described.
4A is a horizontal sectional view of the double-pipe pile 48, FIG. 4B is a vertical partial cross-sectional view, and FIGS. 5A to 5C all illustrate a construction method of the double-pipe pile 48. It is a vertical sectional view for doing.

As shown in FIGS. 4A and 4B, the lateral rib 46 has an outer peripheral edge cut along the inner peripheral surface 44N of the outer steel pipe 44, and an inner peripheral edge cut along the outer peripheral surface 42G of the support pile 42. It is a fan-shaped steel plate.
The outer peripheral edge of the lateral rib 46 is fixed to the inner peripheral surface 44N of the outer steel pipe 44, and the inner peripheral edge is opposed to the outer peripheral surface 42G of the support pile 42 with a predetermined gap d4. Four horizontal ribs 46 are arranged in the horizontal direction, and a predetermined distance S <b> 1 is provided between adjacent horizontal ribs 46. Note that the number of the lateral ribs 46 and the distance S1 between the adjacent ribs 46 are merely a guide and can be arbitrarily set.
Further, the lateral ribs 46 are discretely attached with a predetermined distance H3 in the depth direction.

Here, the gap d4 between the lateral rib 46 and the support pile 42 is larger than the amplitude during vibration of the support pile 42, and the vibration of the support pile 42 is not transmitted to the outer steel pipe 44. Thereby, transmission of the vibration from the support pile 42 to the surface layer ground 64 is suppressed.
On the other hand, when the support pile 42 receives a lateral load, the support pile 42 moves sideways, and the lateral rib 46 contacts the support pile 42. Thereby, the further deformation | transformation of the support pile 42 is suppressed.

  Moreover, when the support pile 42 deform | transforms with a vertical load, the horizontal rib 46 contact | abuts to the support pile 42 outer peripheral surface, and the further deformation | transformation is suppressed. Thereby, since the buckling is suppressed by the lateral rib 46, the buckling can be prevented without increasing the pile diameter more than necessary.

Next, the construction method of the double pipe pile 48 is demonstrated using FIG. 5 (A)-(C).
First, as shown in FIG. 5A, the ground (surface layer ground 64, intermediate ground layer 63, gravel layer 60, and support layer 62) is excavated to form excavation holes 66. The excavation hole 66 excavates from the ground surface 18 to the depth reaching the gravel layer 60 with the diameter of the outer steel pipe 44, and further excavates to the depth reaching the support layer 62 from the gravel layer 60 with the diameter of the support pile 42.

Next, as shown in FIG. 5B, the outer steel pipe 44 with the lateral ribs 46 attached to the inner peripheral surface is buried in the excavation hole 66 to a depth reaching the gravel layer 60. Next, the outer peripheral wall steel pipe 72 is inserted into the outer steel pipe 44, and the reinforcing bar 70 for the support pile 42 is arranged inside the outer peripheral wall steel pipe 72.
The outer peripheral wall steel pipe 72 is inserted to a depth reaching the gravel layer 60, and the reinforcing bar 70 is arranged to a depth reaching the support layer 62. In addition, the outer peripheral wall steel pipe 72 exhibits a function as a formwork at the time of casting concrete, and may be strong enough to withstand the pressure at the time of casting concrete, and a thin steel pipe is adopted.

  Next, as shown in FIG. 5C, concrete is placed inside the outer peripheral wall steel pipe 72. Thereby, the support pile 42 is produced at a depth reaching the support layer 62 inside the outer steel pipe 44 with a predetermined distance d4 from the lateral rib 46.

  The double pipe pile 48 described above can be used in place of the double pipe pile 21 described in the first embodiment. Thereby, since the buckling of the support pile 42 is suppressed by the double pipe pile 48, even if the pile length of the field part 12 of the arena 10 is long, the buckling of the support pile 42 can be suppressed. .

In addition, you may provide the double pipe pile 48 of this embodiment not only under the floor slab 16 of the field part 12 but under the passenger seat part 14 containing the floor slab 28. FIG.
Moreover, the support pile 42 demonstrated the case of the cast-in-place concrete pile. However, the present invention is not limited to this, and an existing pile may be used.
Other configurations are the same as those in the first embodiment, and a description thereof will be omitted.

(Fourth embodiment)
The double pipe pile 58 which concerns on 4th Embodiment is demonstrated using FIG. 6 (A), (B), FIG. 7 (A)-(D), FIG. 8 (A), and (B).
As shown in FIGS. 6A and 6B, the double pipe pile 58 has a double pipe according to the third embodiment in that a plurality of longitudinal ribs (buckling stoppers) 56 are provided on the outer steel pipe 54. It differs from the pile 48. The difference will be mainly described.

  A plurality of vertical ribs 56 are discretely attached to the inner peripheral surface 54N of the outer steel pipe 54 with a predetermined distance H4 in the depth direction. The vertical rib 56 is a steel plate having a trapezoidal shape when viewed from the front, one end surface serving as the base of the trapezoid is attached to the inner peripheral surface 54N of the outer steel pipe 54, and the other end surface serving as the top side of the trapezoid is supported. The outer peripheral surface 52G of the pile 52 and the predetermined clearance gap d5 are opened, and it is opposingly arranged.

Here, the gap d <b> 5 between the support pile 52 and the vertical rib 56 is larger than the amplitude at the time of vibration of the support pile 52, and the vibration of the support pile 52 is not transmitted to the outer steel pipe 54. Thereby, transmission of the vibration from the outer steel pipe 54 to the ground (surface ground 64, intermediate ground 63) is suppressed.
On the other hand, when the support pile 52 receives a lateral load, the support pile 52 moves sideways, and the vertical ribs 56 abut against the support pile 52. Thereby, the further deformation | transformation of the support pile 52 is suppressed.

  Further, when the support pile 52 is deformed by receiving a vertical load, the vertical rib 56 comes into contact with the outer peripheral surface of the support pile 52, and further deformation is suppressed. Thereby, since the buckling of the support pile 52 is suppressed by the vertical ribs 56, the buckling of the support pile 52 can be prevented even if the pile length is long.

Here, the construction method of the double pipe pile 58 is demonstrated.
First, as described in the third embodiment, the ground (surface layer ground 64, intermediate ground layer 63, gravel layer 60, and support layer 62) at the construction position of the double pipe pile 58 is supported with a predetermined diameter and at the tip. Drill to a depth that reaches layer 62 and provide a drilling hole 66.

  Next, as shown in FIG. 7A, the outer steel pipe 54 having the longitudinal ribs 56 provided on the inner peripheral surface is embedded in the excavation hole 66. The vertical ribs 56 are attached in the vertical direction (the direction of the center line of the outer steel pipe 54).

Next, as shown in FIG. 7B, a mold material 74 made of polystyrene foam (foamed material) is attached to the inner peripheral surface of the outer steel pipe 54.
The mold material 74 is formed in a hollow cylindrical body with polystyrene foam and then divided into a plurality of parts in a direction along the center line (see FIG. 8A). Each of the divided formwork materials 74 includes a storage portion for the vertical rib 56, and is formed to have a thickness T2 that covers the tip of the vertical rib 56 with a thickness T1 (thickness T1 = gap d1). The mold material 74 is affixed to the inner peripheral surface of the outer steel pipe 54 without a gap. After the formwork material 74 is attached, the outer peripheral wall is inscribed in the outer steel pipe 54, and the inner peripheral wall becomes a hollow cylindrical body that becomes a columnar cavity. Further, the vertical ribs 56 are stored in a storage portion inside the mold member 74.

  Further, an electric heater (planar heater) 76 is embedded in each mold member 74 (see FIG. 8B). The electric heater 76 is embedded in the side wall near the outer steel pipe 54 and the side wall near the inner peripheral surface that comes into contact with the support pile 52. Thereby, after constructing the support pile 52, by energizing the electric heater 76, the mold material 74 can be dissolved and taken out with a reduced volume.

Next, as shown in FIG. 7C, a reinforcing bar for the support pile 52 is assembled inside the formwork material 74 and inserted into the excavation hole 66. The formwork material 74 serves as a formwork when placing concrete.
Subsequently, concrete is cast into the cavity formed by the formwork material 74, and the support pile 52 is produced.

  Next, as shown in FIG. 7D, the heating wire previously embedded in the mold material 74 is energized, and the surface of the mold material 74 is melted by the heat of the planar heater 76. Thereafter, the unmelted portion of the electric heater 76 and the formwork material 74 is taken out from the excavation hole. Thereby, the support pile 42 is produced inside the vertical rib 56.

In addition, even if it is a case where the pile length of the field part 12 of the arena 10 is long by using the double pipe pile 58 mentioned above instead of the double pipe pile 21 demonstrated in 1st Embodiment, it is the vertical rib 56. Thus, buckling of the support pile 52 is suppressed. Further, buckling can be prevented without increasing the pile diameter of the support pile 52.
Other configurations are the same as those in the first embodiment, and a description thereof will be omitted.

DESCRIPTION OF SYMBOLS 10 Arena 12 Field part 14 Passenger seat part 16 Floor slab 18 Ground surface 20, 24, 32, 42, 52 Support pile 20G, 24G, 32G, 42G, 52G Outer peripheral surface of support pile 22, 26, 34, 44, 54 Outer steel pipe (Cylinder material)
22N, 26N, 34N, 44N, 54N Inner peripheral surface of outer steel pipe (tubular material) 36 Projecting part (buckling prevention means)
46 Lateral rib (Buckling prevention means)
56 Vertical rib (Buckling prevention means)

Claims (1)

In an arena comprising a field part and a passenger seat part surrounding the field part,
While supporting the floor slab of the field part in a state of floating from the ground surface, a support pile of cast-in-place piles or pre-made piles whose lower end part is embedded in the support layer of the ground,
An upper end portion is provided with a gap with the floor slab of the field portion, and the support pile is surrounded by a tubular material with a gap,
Ribs as buckling prevention means that are discretely provided in the depth direction on the inner peripheral surface of the cylindrical member and prevent buckling of the support pile,
Arena with.