JP3093625B2 - Foundation structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foundation structure of a building such as a middle-rise house or a high-rise house or a pier of a highway bridge or a railway bridge, and more particularly to a prefabricated pile and footing. The present invention relates to a basic structure having an improved joint structure with a basic structure.

[0002]

2. Description of the Related Art A foundation structure of this kind is provided in advance on a weak part of the ground, for example, a PHC (high strength prestressed concrete) pile, a PC (prestressed concrete) pile,
After burying and supporting a ready-made hollow pile such as an RC (reinforced concrete) pile, a reinforced concrete footing is formed on the pile integrally with the pile. Conventionally, as shown in FIG. 8, a cylindrical cage 26 is disposed in a pile of a ready-made pile 25 and concrete 27 is cast, and a main reinforcement 28 of the cage 26 in the pile of the pile 25 is extended upward. A substructure 21 having a structure embedded in a footing 22 (hereinafter, referred to as an A type) is generally used.

[0003] In addition, as shown in FIG.
7, and the main bar 28 of the cage bar 26 in the pile of the hollow pile 25 is extended upward and buried in the footing 22 (hereinafter referred to as a B type).

[0004] Further, as shown in FIG.
Around the pile head, a concrete cage 27 is placed and concrete 27 is poured. The main reinforcement 28 'of the cage 26' at the pile head of the hollow pile 25 is extended upward to form the footing 22.
There is a structure buried inside (hereinafter referred to as C type).

FIG. 14 is a longitudinal sectional view showing a procedure for constructing a conventional substructure of a building for the Housing and Urban Development Corporation.
This substructure 21 is similar to the above-mentioned conventional C type. That is, after the four piles 25 are buried and supported in the ground, rockstone C is laid so that the pile heads protrude, and discarded concrete is poured into the bottom of the footing 22. Then, in the pile head buried portion 22a of the footing 22, reinforcing bars 31 are arranged around the pile 25 so as to cross vertically and horizontally and diagonally (FIG. 14A).

[0006] Concrete 27 is embedded in the pile head buried portion 22a.
Is installed. At the same time, concrete 27 'is also cast inside the pile 25 (the inside of the pile head) (FIG. 14B).

The base plate 22 above the pile head buried portion 22 a
Main bar 28, footing skewer bar (cage bar) 28a, column bar 29 forming a column, foundation beam 23
14 are arranged respectively (FIG. 14
(c)).

[0008] A reinforcing member 22b of the footing 22, a foundation beam 23, and the like are surrounded by a formwork, and concrete 27 is poured to the upper end of the foundation beam 23 (FIG. 14 (d)).

[0009]

However, in the conventional substructure 21 described above, the footing 22 is cracked due to the Great Hanshin-Awaji Earthquake that occurred on January 17, 1995, or the footing 22 It was confirmed that a crack was generated at the joint of No. 22. In particular, the cracks in the footing 22 will damage the columns 24 erected on the footing 22 and the foundation beams 23 integrally joined to the footing 22, so it is necessary to prevent at least the occurrence of cracks in the footing 22. There is.

Incidentally, each of the above-mentioned conventional substructures 2
Regarding 1, the present inventors reconfirmed the damage caused by the earthquake by a test. That is, a horizontal force was applied to the above-described A-type to C-type substructures 21 by a test device 51 as described below, and a strength test was particularly performed on a joint between the hollow pile 25 and the footing 22. This test is a strength test against rolling in the event of an earthquake. As shown in FIG. 15, the test apparatus 51 turns the footing 22 upside down with a horizontal reaction force floor 52 as shown in FIG.
It is fastened and fixed by three PC steel rods (outer diameter 50 mm) 53 on the left and right. A hydraulic jack 55 for both pushing and pulling is applied to a reaction wall 54 erected vertically on the reaction floor 52.
Is supported by a pin, and the other end of the hydraulic jack 55 is connected to the outer periphery of the base end of the hollow pile 25 via a pressure band 56 so that a pressing force and a pulling force are applied to the base end of the hollow pile 25. I can give it. This hydraulic jack 55
The pressing force and the pulling force are equivalent to the rolling force of the earthquake. The position of the applied point is two points upward from the bottom of the footing 22.
m height.

In order to apply a vertical load (also referred to as axial force) to the substructure 21,
A pair of columns 57 are erected facing the reaction wall 54, and the columns 5
7, a support frame 58 is erected between the support frame 58 and the reaction wall 54.
9 is installed. The hydraulic jack 60 is suspended downward from substantially the center of the lower surface of the support frame 59, and the hydraulic jack 6 is suspended.
0 at the lower end of the hollow pile 2 of the substructure 21 via the ball seat 61.
5 is in contact with the tip. The reason why the ball seat 61 is provided in this way is to enable the axial force to follow the displacement of the applied point of the hollow pile 25.

Further, the hollow pile 2 is provided by a hydraulic jack 55.
In order to prevent the hollow pile 25 from being displaced in a right angle direction when a horizontal pressing force and a pulling force are applied to the spar 5, the spar member 6 is provided at a substantially middle position in the height direction of the column 57.
2, and a pair of H-shaped steels 63 were laid in parallel between the girder member 62 and the reaction wall 54 so as to sandwich the hollow pile 25. Further, the contact portion of the H-shaped steel 63 with the hollow pile 25 was subjected to Teflon processing.

The dimensions of the substructure 21 and the test apparatus 51 are as shown in FIG. The exam is
In a state where the vertical axial force is not applied and a state where the vertical hydraulic jack 60 applies an axial force of 70 tf to the substructure 21, the hydraulic jack 55 reduces the maximum pressing force and the tensile force to 0 tf. In the case, 17.5 tf, and in the case of the axial force of 70 tf, 25.0 tf were repeatedly applied to the tip portion (loading point) of the hollow pile 25. The load speed at this time is 5 tf / min, and after the load reaches the maximum,
Deformation was increased to the extent that safety could be confirmed.

Test Results (1) A type substructure: When the axial force is 70 tf, FIG.
As shown in (b), the head of the hollow pile 25 came out of the footing 22 and was inclined. No cracks were observed on the surface of the pile, but deep cracks radially extending on the bottom surface of the footing 22 as shown in FIG. 9A, and were connected to the cracks generated on the side surfaces of the footing 22.

Maximum load; 17.4 tf; pile crack load;
Measurement not possible, pile breaking load; measurement not possible When the axial force is 0 tf, the tendency is the same as when the axial force is 70 tf, but the degree of cracking is small.

Maximum load: 6.7 tf, pile crack load; unmeasurable, pile breaking load; unmeasurable (2) B type foundation structure: FIG.
As shown in (b), a large number of bending cracks occur on the surface of the hollow pile 25, and the compression side of the head of the pile 25 is extensively crushed. As shown in FIGS. 11A and 11B, the footing 22
Pile head buried part 22a and the body part (rebar arrangement part) 22 thereabove
From the vicinity of the boundary with b, cracks continued upward and on the side surface.

Maximum load: 26.4 tf, pile crack load: 1
4.1 tf, pile breaking load; 26.4 tf When the axial force is 0 tf, the tendency is similar to that when the axial force is 70 tf, but the degree of cracking is small.

Maximum load: 18.3 tf, pile crack load: 1
2.2tf, pile breaking load; 18.3tf (3) C type substructure: In case of 70tf axial force, Fig. 13
As shown in (b), a large number of bending cracks occur on the surface of the hollow pile 25, and the compression side of the head of the pile 25 is extensively crushed. As shown in FIGS. 13A and 13B, the footing 22
From the vicinity of the boundary between the pile head buried portion 22a and the main body portion 22b thereabove, cracks that continue upward and to the side surface have occurred.

Maximum load: 25.0 tf, pile crack load: 1
4.4 tf, pile breaking load; 25.0 tf When the axial force is 0 tf, the tendency is similar to that when the axial force is 70 tf, but the degree of cracking is small.

Maximum load; 17.5 tf, pile crack load; 1
1.5 tf, pile breaking load; 17.2 tf The above test results are consistent with the above-mentioned damage caused by the earthquake, and it was reconfirmed that the conventional foundation structure has room for improvement.

The present invention has been made in view of the above points, and the joint between a ready-made pile and a footing does not split even in the event of a large earthquake. Pre-stress (clamping) when using the cut-off side of the head of an already-manufactured pile is easy to construct compared to the conventional method. It is an object of the present invention to provide a substructure capable of sufficiently reinforcing a pile head having a reduced state).

[0022]

In order to achieve the above object, a foundation structure of the present invention is a) a foundation structure of a building or a structure, wherein a pile head of a ready-made pile buried and supported in the ground. Around the portion, a steel pipe with double-sided ribs having a diameter larger than the pile diameter and having substantially the same height as the pile diameter is arranged, and b) between the pile at the pile head and between the pile and the steel pipe with double-sided ribs. the both within
Concrete is poured from the lower end to the upper end of the steel pipe with face ribs, and the concrete is placed under the outer peripheral surface of the steel pipe with both face ribs.
A footing and the pile are integrally joined by casting concrete of a predetermined shape forming a part of the footing around the edge from the end to the upper end .

According to the substructure having the above configuration,
When a horizontal force is applied due to the roll at the time of the earthquake, the displacement (relative movement) in the axial direction (perpendicular to the horizontal force) between the pile head and the inner peripheral surface of the steel pipe, and the steel pipe Axial displacement (relative movement) between the outer peripheral surface and the footing in the axial direction (perpendicular to the horizontal force) is prevented by ribs (usually spiral) engraved on the peripheral surface of the steel pipe. That is, the horizontal load is transmitted as the peripheral friction force in the order of concrete to the pile head via the rib on the inner peripheral surface of the steel pipe, then the ready-made pile, and the concrete of the footing is transmitted via the rib on the outer peripheral surface of the steel pipe. , A horizontal load is transmitted as a circumferential friction force. At the same time, concrete, steel pipe, and concrete are interposed between the ready-made pile head and the footing, and the pile head and the footing are integrated through the steel pipe and concrete. Ground reaction force acts directly.

The use of the steel pipe with ribs on both sides causes the following operational difference as compared with the case of using steel pipe with internal ribs. That is, in the above-described type of foundation structure, when a horizontal force acts on the pile when an earthquake occurs, a bending stress acts on the pile head. At this time, in order for the pile to sufficiently exhibit horizontal strength, it is necessary to sufficiently transmit the bending stress generated at the pile head to the footing. For that purpose, the bearing force acting on the periphery of the pile and the strength of the adhesive force must be sufficiently large. In the case of a steel pipe with an internal rib, the degree of integration with the concrete inside the steel pipe is higher than that of the steel pipe without a rib, but the degree of integration with the concrete outside the steel pipe is almost the same as that of the steel pipe without a rib. In contrast, steel pipes with double-sided ribs not only have a high degree of integration with the concrete inside the steel pipe, but also have a high degree of integration with the concrete outside the steel pipe. Strength of the adhesion and the adhesion mainly on the outside of the steel pipe increases. The bending stress transmitted from the pile to the steel pipe through the concrete inside the steel pipe is transmitted to the footing by the supporting force and adhesive force generated between the steel pipe and the concrete outside the steel pipe. The bending stress acting on the footing can be transmitted sufficiently to the footing,
Extremely high strength against earthquakes.

Therefore, the joint state (adhesiveness) of the pile head to the footing is strong, the pile head does not come off from the footing, and stress is not easily concentrated on the joint between the two. Never do.
In addition, since a prefabricated pile and a steel pipe with ribs on both sides are basically used, the number of components is small and the structure is simple, so that the construction is easy and the number of working days is reduced.

[0026] As set forth in claim 2, c) a fixed stitch having a length slightly longer than the pile diameter is fixed to the tip of the outer peripheral surface of the steel pipe with double-sided ribs at intervals in the circumferential direction. Can be buried inside.

According to the second aspect of the present invention, a plurality of fixing streaks fixed to the outer peripheral end portion of the steel pipe are required as compared with the first embodiment, but these fixing streaks are footing. Buried above the pile head, the joint between the steel pipe and the footing becomes stronger.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a substructure according to the present invention will be described below with reference to the drawings. FIG. 1A is a longitudinal sectional view showing a first embodiment of the substructure, and the sectional positions are different on the left and right across a center line. FIG. 1 (b) is a diagram of FIG.
FIG. 2A is a cross-sectional view taken along the line bb of FIG.
FIG. 2B is a cross-sectional view taken along the line cc of FIG. FIG. 3 (a)
3 (c) are sectional views corresponding to FIG. 1 (a), each showing a procedure for constructing the substructure of FIG. 1 (a).

In the substructure 1 of this embodiment, a plurality of cubic footings 2 as shown in FIGS. 1 and 2 are arranged at predetermined intervals, and adjacent footings 2 are connected via a foundation beam 3. ing. On the center of each footing 2, a pillar 4 of a building such as a condominium in this example is erected integrally. In the ground A, in this example, for one footing 2, four ready-made piles (here, PHC piles) 5 are arranged at regular intervals so as to correspond to corners of a square when viewed from above the footing 2. It is buried and supported by casting. The PHC pile 5 is a cylindrical hollow pile made of reinforced concrete, the lower end of which is open or closed, and the upper end of which is open.

A steel pipe 6 with double-sided ribs is arranged around the pile heads of the piles 5. These steel pipes 6 are piles 5
It has a diameter larger than the outer diameter of the stake 5 and is made of a cylindrical body having substantially the same height as the outer diameter of the pile 5, and has a number of spiral ribs 6a projecting from the inner and outer peripheral surfaces at regular intervals. In addition, a large number of fixing streaks 7 having dimensions slightly longer than the height of the steel pipe 6 are arranged at regular intervals in the circumferential direction at the distal end portion of the outer peripheral surface of the steel pipe 6,
It is fixed by welding so as to protrude upward.

Each footing 2 has a pile head joint (pile head buried part) 2a in which the pile head of the pile 5 is buried and integrally joined;
Above it, a large number of main streaks 8 and stitches 8a are arranged crosswise and transversely and arranged in a cage-like arrangement 2b.
As shown in FIG. 2, the pile head joint 2a has a simple structure in which a double-sided ribbed steel pipe 6 to which a fixing bar 7 shown in FIG. Column 4 has column bars 10
However, beam reinforcements 12 are arranged on the foundation beams 3 along the columns 4 or the foundation beams 3 from inside the reinforcement arrangement portions 2b as shown in FIG. And footing 2, pillar 4 and foundation beam 3,
Each is formed by casting concrete 11 using a formwork, and is integrally connected. At the same time, concrete 11 ′ is cast inside the pile 5.

As described above, the substructure 1 of the present embodiment
As shown in FIG. 3, the construction procedure is as follows: four piles 5 are buried in the ground so that the pile heads protrude, and are supported. And lay concrete. Then, a steel pipe 6 with double-sided ribs formed by welding a large number of anchoring streaks 7 upward to the distal end portion of the outer peripheral surface is provided on each pile 5
(Fig. 3 (a)).

A main bar 8 and a stud bar 8 a forming the base plate 2, a column bar 10 forming a column, a beam bar 12 forming a base beam 3, and the like are arranged (FIG. 3B).

The foundation plate 2, the foundation beam 3, and the like are surrounded by a mold, and concrete 11 is poured to the upper end of the foundation beam 3. At this time, concrete 1
1 'is cast (FIG. 3 (c)).

The substructure 1 is completed as described above.

FIG. 4 shows a second embodiment of the substructure according to the present invention. FIG. 4 (a) is a sectional view taken along line bb of FIG. 4 (b), and FIG. 4 (b) is a longitudinal sectional view. It is. In the substructure 1 ′ of this example,
The point that the pile head of one PHC pile 5 is embedded and joined to the cubic base plate 2 is different from the foundation structure 1 of the above embodiment, but the other points are common. . In the case of this example, the outer diameter of the PHC pile 5 is 500 mm, and the thickness of the pile 5 is 8
0 mm. Outer diameter of steel pipe 6 with ribs on both sides is 650mm
The height is 500 mm, and the length of the fixing streaks 7 protruding from the upper end of the steel pipe 6 is 600 mm. The width and depth of the footing 2 are each 1200 mm,
The height is 1100mm and the height of the pile head joint 2a is 500m
m, the height of the bar arrangement part 2b is 600 mm. In other words, the figure
4 (b), the inside of the pile 5 of the pile head 2a and the pile 5
The steel pipe 6 with the double-sided ribs is provided between the steel pipe 6 with the double-sided ribs.
When concrete is poured from the lower end to the upper end
From the lower end to the upper end of the outer peripheral surface of the steel pipe 6 with the ribs on both sides.
Pile head joint 2 of footing 2
a is formed integrally with the upper reinforcing bar 2b. And
A foundation beam 3 is integrally connected to both sides of the footing 2.

The substructure 1 'constructed as described above was tested by the above-described test apparatus 51 (see FIG. 15), and the results were as follows.
That is, the above-mentioned substructure 1 ′ is fixed upside down with a steel bar 53 on the reaction floor 52, and a vertical load of 70 tf is applied by the hydraulic jack 60, and a vertical load is not applied. The test was performed. The test is approximately 2.5tf
The pressing force and the pulling force were repeatedly applied by the hydraulic jack 55 up to a load of 25.0 tf when the axial force was 70 tf at the pitch and up to a load of 17.5 tf when the axial force was 0 tf.

Test Results When the axial force is 70 tf, as shown in FIG. 5B, a large number of bending cracks occur on the surface of the PHC pile 5 and the compression side of the head of the pile 5 is widely crushed. However, FIGS. 5 (a) and 5 (b)
As shown in (1), no crack is generated on any of the top surface, the side surface, and the bottom surface of the footing 2.

Maximum load: 25.0 tf, pile crack load: 1
4.2tf, pile breaking load; 24.8tf (The above loads are measured values when the thickness of the pile 5 is 83.0mm.) When the axial force is 0tf, the axial force is 70t.
There is a similar tendency as in the case of f, but the degree of cracking is small.

Maximum load: 17.5 tf, pile crack load: 1
2.2tf, pile breaking load; 17.3tf (However, the above loads are measured values when the thickness of the pile 5 is 85.8 mm) Comparison with the conventional (1) As shown in FIG. Although the PHC pile 5 was cracked or partially crushed, the joint state between the footing 2 and the pile 5 did not change, and the footing 2 did not have any cracks. It is presumed that buildings and structures standing on top of it will not be affected even if they are rolled by a rather large earthquake.

(2) Compared with the conventional construction procedure of the foundation 21 in the Residential Urban Development Corporation shown in FIG. 14, in the same foundation 21, the reinforcing bars for reinforcing vertically and horizontally and diagonally also in the pile head buried portion 22a. After arranging the reinforcement, concrete 2
7 is laid, and a main reinforcing bar and a skewing bar are laid on the reinforcing bar 22b above the concrete reinforcing bar 22 and concrete 2 is extended to the upper end of the foundation beam 23.
In this case, it is not necessary to arrange reinforcing bars in the pile head buried portion 22a and to once cast concrete 27 in the pile head buried portion 22a. The construction is simplified by the minute, and the construction period is shortened.

FIG. 6 shows a third embodiment of the substructure according to the present invention. FIG. 6 (a) is a sectional view taken along line bb of FIG. 6 (b), and FIG. 6 (b) is a longitudinal sectional view. It is. In this example, the substructure 1 ″ is P
The point that the steel pipe 6 with double-sided ribs arranged around the pile head of the HC pile 5 is not provided with the anchoring bar 7 is different from the substructure 1 ′ of the second embodiment, but other points are as follows. Have in common. Also in the case of this example, the outer diameter of the PHC pile 5 is 500 mm, the thickness of the pile 5 is 80 mm, and the outer diameter of the steel pipe 6 with double-sided ribs is 6 mm.
50 mm and its height is 500 mm. The width and depth of the footing 2 are each 1200 mm, the height is 1100 mm, and the height of the pile head joint 2a is 500 m.
m, the height of the bar arrangement part 2b is also 600 mm in common. That is, as shown in FIG.
In the pile 5 and between the pile 5 and the steel pipe 6 with ribs on both sides,
Concrete from bottom to top of steel pipe 6 with face rib
And beneath the outer peripheral surface of the steel pipe 6 with ribs on both sides.
Pour concrete from end to top and footing
2 is formed integrally with the upper reinforcing bar 2b.
ing.

Now, for the substructure 1 ″ constructed as described above, the above-described test apparatus 51 (see FIG. 15)
, And the results were as follows. That is, the above-mentioned substructure 1 ″ is fixed upside down with the steel bar 53 on the reaction floor 52, and the vertical load is applied 70 tf by the hydraulic jack 60 and the vertical load is not applied. The test was performed at a pitch of approximately 2.5 tf and a maximum of 2 at a shaft force of 70 tf.
The pressing force and the pulling force were repeatedly applied by the hydraulic jack 55 up to a load of 5.0 tf, or up to a load of 17.5 tf when the axial force was 0 tf.

As a result of the test , when the axial force is 70 tf, as shown in FIG. 7B, a large number of bending cracks occur on the surface of the PHC pile 5, and the compression side of the head of the pile 5 is extensively crushed. However, FIGS. 7 (a) and 7 (b)
As shown in (1), no crack is generated on any of the top surface, the side surface, and the bottom surface of the footing 2. Therefore,
It is common to the substructure 1 'of the second embodiment.

Maximum load; 26.2 tf, pile crack load; 1
4.6 tf, pile breaking load; 26.2 tf (however, the above loads are such that the thickness of the pile 5 is 106.5 mm
In the case of an axial force of 0 tf, the axial force is also 70 tf.
There is a similar tendency as in the case of tf, but the degree of cracking is small.

Maximum load: 17.9 tf, pile crack load: 1
2.2tf, pile breaking load; 17.5tf (The above loads are measured values when the thickness of the pile 5 is 102 mm) Comparison with the conventional (1) As shown in FIG. 5 was cracked or partially crushed, but the connection between the footing 2 and the pile 5 did not change, and the footing 2 did not have any cracks. It is presumed that the buildings and structures erected on the example substructure 1 "are not affected even if they are rolled by a considerably large earthquake.

(2) Compared with the conventional procedure for constructing the foundation 21 in the Residential Urban Development Corporation shown in FIG. 14, in the foundation 21 the reinforcing bars are laid vertically and horizontally at the pile head buried portion 22a. Once the concrete 27
After placing, concrete bars 27 are laid to the upper ends of the foundation beams by arranging the main reinforcing bars and skewer bars in the reinforcing bars 22b above the reinforcing bars. It is not necessary to arrange the reinforcing bars and to once cast the concrete 27 into the pile head buried portion 22a, so that the construction is simplified by these operations and the construction period is shortened.

Here, a table comparing the performance of the above-described substructures of the present invention and the conventional example is shown below. However, in the example of the present invention and the conventional A-type to C-type foundation structures, since the pile was broken, the maximum load was determined to be substantially the same by determining the strength of the pile. Moreover, since the pile thickness was slightly different as described below, there was some variation in the measured values.

[Comparative Table] Second Embodiment Third Embodiment Conventional A Conventional B Conventional C Maximum load 17.5tf 17.9tf 6.4tf 16.7tf 16.9tf (no axial force) Pile wall thickness 85.8mm Same as 102.0mm Same 94mm 106.5mm 93.0mm Maximum load 25.0tf 23.5tf 16.5tf 24.6tf 25.0tf (axial force 70tf) Pile thickness 83.0mm 106.5mm 92.5mm 96.5mm 91.8mm Workability Very good Very good Good Good Good Footing Very high Very high Insufficient Insufficient Insufficient reinforcement effect Pile reinforcement effect Very high Very high Insufficient High

[0050]

As is apparent from the above description,
The substructure according to the present invention has the following excellent effects. (1) The joint of the pile head to the footing is strong, the pile head does not come out of the footing due to the roll due to the earthquake, and stress is not easily concentrated at the joint of both, so cracking occurs in the footing. There is no. Therefore, it is possible to prevent the building erected on the substructure or the pier of the highway from collapsing due to the earthquake. Further, since the steel pipe with the ribs on both sides is arranged around the pile head of the ready-made footing pile, the number of constituent members is small and the structure is simple, so that the construction is easy and the construction period can be greatly reduced.

(2) In the substructure according to the second aspect, a plurality of fixing streaks fixed to the tip of the outer peripheral surface of the steel pipe are required in addition to those in the first aspect. By being buried and supported above the pile head of the footing, the horizontal force transmitted from the pile to the steel pipe with double-sided ribs will be more reliably transmitted to the concrete part of the footing, and the pile head will be used only with the steel pipe with double-sided ribs. As compared with the first aspect of the present invention, the bonding between the steel pipe with double-sided ribs and the footing is further strengthened, and the reinforcing action is improved.

[Brief description of the drawings]

FIG. 1 (a) is a longitudinal sectional view showing a first embodiment of a substructure according to the present invention. FIG. 1B is a cross-sectional view taken along line aa of FIG.

FIG. 2A is a sectional view taken along the line bb of FIG.
FIG. 2B is a cross-sectional view taken along line cc of FIG.

FIGS. 3 (a) to 3 (c) sequentially show the construction procedure of the substructure of FIG. 1 (a), and are sectional views corresponding to FIG. 1 (a).

4A and 4B show a second embodiment of the substructure according to the present invention, wherein FIG. 4A is a sectional view taken along line bb of FIG. 4B, and FIG. 4B is a longitudinal sectional view. .

FIG. 5 shows the result of an earthquake roll test.
5A is a bottom view of the substructure of FIG. 4A, and FIG. 5B is a side view of the substructure of FIG. 4A.

6A and 6B show a third embodiment of the substructure according to the present invention, wherein FIG. 6A is a sectional view taken along line bb of FIG. 6B, and FIG. 6B is a longitudinal sectional view. .

FIG. 7 shows the results of an earthquake roll test.
7A is a bottom view of the substructure shown in FIG. 6A, and FIG. 7B is a side view of the substructure shown in FIG. 6A.

FIG. 8 shows a conventional substructure (A type).
8A is a longitudinal sectional view, and FIG. 8B is a sectional view taken along line bb of FIG. 8A.

FIG. 9 shows the results of an earthquake roll test.
9A is a bottom view of the substructure shown in FIG. 8A, and FIG. 9B is a side view of the substructure shown in FIG. 8A.

10 (a) is a longitudinal sectional view, and FIG. 10 (b) is a sectional view taken along line bb of FIG. 10 (a), showing a conventional substructure (B type).

FIG. 11 shows the results of an earthquake roll test. FIG. 11 (a) is a bottom view of the foundation structure shown in FIG. 10 (a), and FIG. 11 (b) is a foundation view shown in FIG. 10 (a). It is a side view of a structure.

12A and 12B show a conventional substructure (C type), in which FIG. 12A is a longitudinal sectional view, and FIG. 12B is a sectional view taken along line bb of FIG. 12A.

FIG. 13 shows the results of an earthquake roll test. FIG. 13 (a) is a bottom view of the foundation structure of FIG. 12 (a), and FIG. 13 (b) is the foundation of FIG. 12 (a). It is a side view of a structure.

14 (a) to 14 (d) are longitudinal sectional views showing a procedure for constructing a conventional substructure of a building for the Housing and Urban Improvement Corporation, respectively.

15A and 15B show a test device for performing a roll test of an earthquake, wherein FIG. 15A is a plan view and FIG. 15B is a front view.

[Explanation of symbols]

 1 ・ 1 ′ ・ 1 ”Foundation 2 Footing 5 Precast pile (PHC pile) 6 Steel pipe with double-sided ribs 7 Anchorage 11 ・ 11 ′ Concrete

────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Shinsuke Namba 12-20 Ikeda-cho, Nishinomiya-shi, Hyogo Arai-gumi Co., Ltd. (56) References: Shokai Sho 59-76646 (JP, U) 50421 (JP, Y2) Jikken Hei 3-38275 (JP, Y2) (58) Field surveyed (Int. Cl. ⁷ , DB name) E02D 27/12 E02D 27/34

Claims (2)

(57) [Claims] Claims: 1. A building or a substructure of a building,
Around a pile head of a ready-made pile buried and supported in the ground, a steel pipe with double-sided ribs having a diameter larger than the pile diameter and having substantially the same height as the pile diameter is arranged, inside the pile at the pile head and A concrete is cast from the lower end to the upper end of the steel pipe with double-sided ribs in the space between the pile and the steel pipe with double-sided ribs.
Part of the footing around the bottom and top edges of the surface
A substructure in which a footing and the pile are integrally joined by casting concrete having a predetermined shape. 2. A fixing pipe having a fixed length slightly longer than the pile diameter is fixed to the tip of the outer peripheral surface of the steel pipe with double-sided ribs at intervals in a circumferential direction, and is embedded in the footing. Substructure.