JP2005307734A - Joint structure of column and pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To use a steel pipe pile having diameter conforming to structure design in one column one pile integrating construction method. <P>SOLUTION: In this joint structure of the column and the pile composed of the column 2 of a structure, the steel pipe pile 1 erected in the ground, a foundation beam 4 supporting the structure, and a just above beam supporting a story just above the foundation beam, the column 2 has a buried column 2a inserted into a pile head 1a of the steel pipe pile 1 and fixed by concrete 3 and a beam joint part in which the foundation beam 4 is joined with the column 2 in the horizontal direction. The maximum outside diameter of cross section of the buried column 2a is set to be smaller than the maximum outside diameter of a crossing face of an upper face of the foundation beam and the column 2. Rigidity of the foundation beam 4 is set to be double rigidity of the just above beam or less (excepting 0). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a joint structure between a pillar and a pile in a steel structure.

  At the pile head joint of the steel structure with the steel pipe pile foundation as the lower structure, a steel pipe with a diameter larger than the outer diameter of this pile is placed at the pile head, the lower end of the column is inserted into the steel pipe, and the concrete is placed in the steel pipe. There has been proposed a construction method (hereinafter referred to as a double steel pipe-type pillar pile joint construction method) in which a pile and a column are determined by filling and building a footing (refer to, for example, Patent Document 1).

  In addition, in the steel structure pile head joint with the pile foundation as the lower structure, a column steel frame is inserted into the pile head, concrete is filled into the pile head, and the pile head is connected (in this way, the pile head is connected) A construction method that realizes a structure in which there is no underground beam and a column rises directly from a pile has been proposed (particularly referred to as a single pillar-one pile construction method) (see, for example, Patent Document 2).

JP 2000-355938 A Japanese Patent Laid-Open No. 3-51428

  By the way, in the double steel pipe column pile joining method, the pile and the column are joined via a steel pipe reinforced type footing. Therefore, the amount of construction waste soil accompanying this cannot be suppressed.

  On the other hand, in the one-column / one-pile integrated construction method, it is possible to omit footing, and advantages such as excavation soil reduction and construction period shortening can be obtained compared to the double steel pipe-type column pile joining method. On the other hand, when compared with cast-in-place concrete piles with the same axial strength, steel pipe piles have a higher vertical bearing capacity and tend to be thinner than cast-in-place concrete piles. It is difficult to secure a sufficient margin for insertion into the pipe, and in order to realize the joint structure, a double steel pipe type is used, or the steel pipe pile diameter is made larger than the structural design diameter, or It is necessary to make the embedded pillar thinner.

  This will be described in more detail based on the explanatory view of the moment that the beam shown in FIGS. Here, for the sake of simplicity, it is assumed that there is no basement. In the case of a frame without a foundation beam as shown in FIG. 14, the bending moment tends to increase from the ground surface to the underground part, and the embedded column is made thin so that it can be inserted into the pile head joint located in the ground. Doing this leads to a decrease in the yield strength (hereinafter referred to simply as “strength”) of the bending moment (hereinafter referred to simply as “moment”), and this part becomes a structural weak point. Therefore, it is not desirable in design.

On the other hand, as shown in FIG. 13, in a frame with a foundation beam that supports the lowest floor of the structure, according to normal design practice, the foundation beam is sufficient to handle the upper and lower structures separated in design. A beam that supports the floor directly above the foundation beam (hereinafter referred to as the “direct beam”. In the figure, it is referred to as the “second floor beam”). It is designed as a cross-section with a crest height. This converted to the stiffness of the beam (= 3 th power), the footing beams stiffness, is at least 2 ^three times the stiffness of the right above the beam (2 Kaihari). In such a structure, as shown in the moment diagram of FIG. 15, the embedded column moment Mpt tends to be larger than the column base moment M1b, and the embedded column is more than the column on the lowest floor (the first floor in this figure). However, it is necessary to design with a large cross section, and it becomes more difficult to secure a margin for the cross section in order to insert the embedded column into the steel pipe pile head. In other words, the diameter of the steel pipe pile is also a precondition determined by the support load in the structural design, but the steel pipe pile tends to have a smaller diameter than the cast-in-place concrete pile as described above. When a steel pipe pile having a pile diameter is used, it becomes difficult to secure a margin on the cross section necessary for inserting the embedded column into the steel pipe pile head. For this reason, conventionally, a steel pipe pile having a larger pile diameter than the structural design pile diameter is used, thereby securing a margin on the cross section for inserting the embedded column into the steel pipe pile head.

  However, the usual design practice of “making the foundation beam stiff enough” is a necessary condition for the upper and lower separation design, not necessarily to satisfy the structural requirements. In recent years, such as a method for designing the upper and lower parts of an integrated analysis and designing the stress, and a method for considering the influence of the pile by replacing the effect of the pile acting on the foundation beam with a horizontal spring, etc. Analysis methods that can calculate behavior more accurately are also being used. According to this, since the influence of the ground can be appropriately taken into consideration, it is not necessary to make a “sufficiently rigid foundation beam” which is a necessary condition for the upper and lower part separation design. Then, by examining the present inventors, by making the foundation beam rigidity softer than the “sufficiently rigid foundation beam”, which is a necessary condition for the upper and lower part separation design, as shown in the moment diagram of FIG. It was found that the moment Mpt can be made smaller than the column base moment M1b, and the embedded column can be made smaller than the column section of the first floor.

  The technical subject of this invention is making it possible to use the steel pipe pile of the pile diameter as a structural design in the 1 pillar 1 pile integrated construction method.

(1) The column-pile joint structure according to the present invention has the following configuration. That is, a pillar and a pile consisting of a pillar of a structure, a steel pipe pile standing in the ground, a foundation beam that supports the structure, and an upper beam that supports a floor directly above the foundation beam It is a joint structure, and the column has an embedded column that is inserted into a pile head of a steel pipe pile and fixed with concrete, and a beam joint in which a foundation beam is joined in a horizontal direction to the column, Furthermore, the maximum outer diameter dimension of the embedded column cross section is set to be smaller than the maximum outer diameter dimension of the cross section of the crossing surface between the upper surface of the foundation beam and the column, and the rigidity of the foundation beam is equal to that of the upper beam. It is set to 2 times or less (excluding 0).
In the present invention, the upper structure included in the “upper and lower part separation design” when the structure is separated into upper and lower parts refers to structures such as columns and beams that are higher than the foundation beam. On the other hand, the substructure refers to structures such as piles and footings deeper than the foundation beam. The foundation beam is involved in both the superstructure and the substructure. Furthermore, the maximum outer diameter dimension refers to the diameter of a circle circumscribing the cross section, and serves as an index for comparing the sizes of the column cross sections.

(2) The column-pile joint structure according to the present invention has the following configuration. That is, a pillar of a structure, a steel pipe pile standing in the ground, a foundation beam that supports the structure, an upper beam that supports a floor directly above the foundation beam, and at least the pillar It consists of a column joint part to be joined, a beam joint part to which a foundation beam is attached in a horizontal direction and joined, and a joint member having an embedded pillar inserted into a pile head of a steel pipe pile and fixed with concrete. It is a column-pile joint structure, and the joint member is configured such that the maximum outer diameter dimension of the embedded column cross section is set smaller than the maximum outer diameter dimension of the cross section of the column joint portion, and the foundation beam and the beam joint portion. The rigidity is set to be equal to or less than twice the rigidity of the beam directly above (excluding 0).

(3) The column-pile joint structure according to the present invention has the following configuration. That is, a pillar and a pile consisting of a pillar of a structure, a steel pipe pile standing in the ground, a foundation beam that supports the structure, and an upper beam that supports a floor directly above the foundation beam It is a joint structure, and the column has an embedded column that is inserted into a pile head of a steel pipe pile and fixed with concrete, and a beam joint in which a foundation beam is joined in a horizontal direction to the column, Furthermore, the maximum outer diameter dimension of the embedded column cross section is set smaller than the maximum outer diameter dimension of the crossing surface between the upper surface of the foundation beam and the column, and the rigidity of the foundation beam is twice that of the upper beam. Hereinafter, it is set to 1 or more times.

(4) The column-pile joint structure according to the present invention has the following configuration. That is, a pillar of a structure, a steel pipe pile standing in the ground, a foundation beam that supports the structure, an upper beam that supports a floor directly above the foundation beam, and at least the pillar It consists of a column joint part to be joined, a beam joint part to which a foundation beam is attached in a horizontal direction and joined, and a joint member having an embedded pillar inserted into a pile head of a steel pipe pile and fixed with concrete. It is a column-pile joint structure, and the joint member is configured such that the maximum outer diameter dimension of the embedded column cross section is set smaller than the maximum outer diameter dimension of the cross section of the column joint portion, and the foundation beam and the beam joint portion. The rigidity is set to 2 times or less and 1 time or more of the rigidity of the beam directly above.

(5) In the column-pile joint structure according to the present invention, the embedded column has a hollow circular cross section.

(6) In the column-pile joint structure according to the present invention, the embedded column has a solid circular cross section.

(7) The column / pile joint structure according to the present invention is a steel pipe pile head provided with an embedded column extraction restraint ring.

(8) The column-pile joint structure according to the present invention is provided with a plurality of protrusions on the inner surface of the steel pipe pile head.

In the joint structure of columns and piles according to (1) the present invention, the stiffness of a requirement of the conventional upper and lower separation design "sufficient rigid footing beams", i.e. at least two ^3-fold stiffness directly above the beam Since the foundation beam stiffness is softer than that of the foundation beam (with a stiffness of twice or less (excluding 0) than that of the directly above beam), the embedded column as shown in the moment diagram of FIG. The moment Mpt can be made smaller than the column base moment M1b, and the embedded column can be made smaller than the column section of the lowest floor (the first floor in the figure). For this reason, it is easy to secure a margin for inserting the embedded column into the steel pipe pile head, and it is possible to use a steel pipe pile having a pile diameter according to the structural design in the one-column / one-pile integrated construction method.

(2) even in the junction structure of the pillars and piles according to the present invention, the stiffness of a requirement of the conventional upper and lower separation design "sufficient rigid foundation beams" (at least 2 ^three times the stiffness of the right above the beam) In comparison, since the rigidity of the foundation beam and the beam joint is less than twice the rigidity of the upper beam (except 0), the embedded column moment Mpt is set as shown in the moment diagram of FIG. It can be made smaller than the column base moment M1b, and the embedded column can be made smaller than the column cross section of the lowest floor (the first floor in the figure). For this reason, it is easy to secure a margin for inserting the embedded column of the joint member into the steel pipe pile head, and the steel pipe pile having the pile diameter as the structural design can be used in the one-column / one-pile integrated construction method. .

(3) In the column-pile joint structure according to the present invention, since the rigidity of the foundation beam is set to be 2 times or less and 1 time or more of the rigidity of the upper beam, while ensuring the rigidity of the pile, As shown in the explanatory diagram of the pile head displacement in FIG. 10, an increase in the pile head displacement can be suppressed. And it becomes easy to secure a margin for inserting the embedded column into the steel pipe pile head, and the steel pipe pile having the pile diameter as the structural design can be used in the one pillar / one pile integrated construction method.

(4) Even in the column-pile joint structure according to the present invention, the rigidity of the foundation beam and the beam joint is set to be 2 times or less and 1 time or more of the stiffness of the upper beam. While ensuring, the increase in pile head displacement can be suppressed as shown in the explanatory diagram of pile head displacement in FIG. And it becomes easy to secure a margin for inserting the embedded column into the steel pipe pile head, and the steel pipe pile having the pile diameter as the structural design can be used in the one pillar / one pile integrated construction method.

(5) In the column-pile joint structure according to the present invention, since the section of the embedded column is a hollow circular section, the radial distance from the center is uniform in all directions, and there is no protrusion to the outer periphery. The maximum outer diameter dimension is smaller than, for example, a hollow square section having the same plate thickness and the same moment of inertia of the same section. For this reason, when the pile construction position is shifted, the amount of error absorption is greater than that of the hollow square cross section, and the joining work between the column and the pile becomes easy.

(6) In the column / pile joint structure according to the present invention, since the cross section of the embedded column is a solid circular cross section, it is easy to ensure the yield strength of the embedded column, and the diameter can be further reduced.

(7) In the column-pile joint structure according to the present invention, since the extraction restraint ring of the embedded column insertion portion is installed at the steel pipe pile head, the shear splitting and tensile fracture of the concrete confirmed in the embedded column base structure Can be prevented, and brittle fracture of the joint can be prevented. As a result, sufficient plastic deformation of the steel frame can be promoted.

(8) In the column-pile joint structure according to the present invention, since a plurality of protrusions are provided on the inner surface of the steel pipe pile head, the adhesive strength of the concrete is increased, and the concrete shear splitting confirmed in the embedded column base structure And tensile fracture can be prevented, and brittle fracture of the joint can be prevented. As a result, sufficient plastic deformation of the steel frame can be promoted.

Embodiment 1 FIG.
Hereinafter, the present invention will be described based on illustrated embodiments.
1 is a longitudinal sectional view schematically showing an example of a column-pile joint structure according to Embodiment 1 of the present invention, FIG. 2 is a longitudinal sectional view schematically showing another example, and FIG. A graph showing the relationship between the embedded column moment Mpt and the N value of the ground when the stiffness is changed, with the embedded column moment Mpt on the vertical axis and the embedded column moment Mo on the “sufficiently rigid foundation beam” The horizontal axis is the N value of the ground. FIG. 4 is an explanatory diagram of the maximum outer diameter dimension in the hollow circular section and the hollow square section having the same plate thickness and the same section first moment, and FIG. 5 shows the advantage of the hollow circular section with respect to the hollow square section in relation to the steel pipe pile. It is explanatory drawing.

  1 and 2, reference numeral 1 denotes a steel pipe pile standing in a vertical hole bored by an auger or the like, 2 denotes a steel column of a structure, The steel embedded pillar 2a located at the lower end and below the surface formed by the lower end of the below-mentioned foundation beam is inserted, and the concrete 3 is filled to be decided. In other words, the column 2 has a beam joint portion above the embedded column 2a to which a below-described foundation beam is attached and joined in the horizontal direction. 4 is a steel foundation beam made of H-shaped steel, which is less than twice the stiffness of the upper beam (not shown) (excluding 0) and is placed directly above the pile head 1a, and 5 is installed at the upper end of the pile head 1a. This is an extraction restraint ring that prevents the insertion of the embedded column insertion portion, and has the function of preventing the shear splitting and tensile failure of the concrete 3 and the brittle failure of the joint, thereby sufficiently plastic deformation of the steel frame Has been encouraged. Reference numeral 6 denotes a steel closing lid that is arranged below the position where the embedded pillar is inserted in the pile head 1a and divides the pile head. The concrete 3 is filled in the compartment, and the compression axial force Is transmitted from the concrete 3 to the steel pipe pile 1 through a closing lid.

  Moreover, the cross-sectional shape of the embedded column 2a below the lower flange 4a, which is the lower end of the steel foundation beam 4, is a hollow circle (FIG. 4), and its diameter (in the case of a circle, the maximum outer diameter is equal to the diameter). D1 is set to be smaller than the diameter D3 of the column 2 above the upper flange 4b, which is the upper end of the steel foundation beam 4, and thereby has a cross section for inserting the embedded column 2a into the pile head 1a. It is easy to secure an allowance.

  Further, here, the cross section of the column 2 up to the lower flange 4a of the steel foundation beam 4 is set to the same size, and the embedded column 2a is formed in a stepped cylindrical shape below the cross section. When there is a concern about stress concentration at the stepped cylindrical step portion that is a transition portion from the column 2 to the embedded column 2a, the transition portion from the column 2 to the embedded column 2a is tapered as shown in FIG. By using the (or inclined surface) 2b, the stress concentration can be relaxed, which is a more preferable form.

In order to grasp the effect of reducing the embedded column moment by reducing the steel foundation beam stiffness, the steel foundation beam stiffness is set as the parameter and the steel foundation beam stiffness is equivalent to that of the directly above beam (line indicated by-●-), part 2 When it is doubled (line indicated by-□-), when it is tripled (line indicated by-*-), or when it is 0.5 times (line indicated by -Δ-), the conventional method (ie, The stress ratio (Mpt / Mo) of the embedded column moment Mo in the case of “designed as“ sufficiently rigid foundation beam ”and the embedded column moment Mpt when the stiffness of the foundation beam is changed is actually used. The investigation was conducted under three kinds of conditions. The result was as shown in FIG. According to this, the surface layer ground N value is 5 and the double rigidity beam has an average stress ratio of 0.85 (see FIG. 16), and the single rigidity beam has an average stress ratio of 0.77. In addition, the stress ratio average 0.90 for the 3x rigid foundation beam, and the embedded column moment between the 2x rigid beam and the 3x rigid beam is almost the same. . Then, from the design philosophy of making the beam rigidity as small as possible, it is sufficient to make the beam twice as rigid, and even if the beam is more rigid, the effect of reducing the moment is low. Here, the softer the steel foundation beam 4 is, the smaller the embedded column moment is, but the vertical load of the steel pipe pile 1 tends to increase. If the steel foundation beam 4 is hard, the load flows to the embedded column for bending (moment), and if the steel foundation beam 4 is soft, the load flows vertically (to the pile) against bending (moment). It means that.
Furthermore, the size of the cross section of the embedded column and the cross section of the bottom floor was compared in the steel foundation beam 4 having twice the rigidity of the upper beam and the steel foundation beam 4 having 0.5 times the rigidity. FIG. 17 is a graph showing the results of investigating the stress ratio (Mpt / M1b) between the column base moment M1b and the embedded column moment Mpt of the column on the lowest floor under three kinds of conditions that are actually used. .
According to this result, the ground N value is about 7 or more and Mpt / M1b is 1.0 or less. That is, the ground N value is about 7 or more, and the section of the embedded column can be made smaller than the column section of the lowest floor. In general, the average N value of the surface ground is secured 7 or more except for soft ground. Therefore, from this result, in the case of normal ground, as in the present invention, the rigidity of the steel foundation beam 4 is limited to a rigidity less than twice the rigidity of the upper beam, so that The diameter can be reduced, and it is easy to secure a margin for inserting the embedded column into the steel pipe pile head.

  Therefore, if the relationship between the steel foundation beam stiffness and the embedded column moment as described above is utilized, and the steel foundation beam stiffness is limited to a stiffness that is twice or less (excluding 0) the stiffness of the upper beam, The relative moment of 2a can be reduced, and thereby the diameter of the embedded pillar 2a can be reduced. And it becomes easy to secure a margin for inserting the embedded column into the steel pipe pile head, and the steel pipe pile having the pile diameter as the structural design can be used in the one pillar / one pile integrated construction method.

The embedded pillar 2a is not limited to the hollow circular cross section described above, but may have a hollow square cross section (FIG. 4), but preferably has a hollow circular cross section. The reason is described below.
That is, the hollow circular cross section has the same thickness and the same moment of inertia, and the distance from the center to the outer periphery is uniform in all directions and has no protrusion. It becomes. On the other hand, in the case of a hollow square cross section, the maximum outer diameter dimension is a diagonal distance D2. Here, the cross-sectional primary moments ₁ Zx, y and ₂ Zx, y of each cross-section are the maximum outer dimensions D1, D2 and the hollow inner / outer diameter ratio α (not the plate thickness t as shown in FIG. 4). Therefore, it is calculated | required by the formula mentioned later. From these, when the hollow circular cross section and the hollow square cross section have the same cross-sectional first moment, when solving for D1 / D2,
D1 / D2 = 0.807
It becomes.
here,
Circular section primary moment ₁ Zx, yf is ₁ Zx, y = (π / 64) (1-α) (D1) ⁴
Square section primary moment ₂ Zx, y is ₂ Zx, y = {(1-α) / 48} (D2) ⁴
It is.
That is, the maximum outer diameter is apparently about 20% smaller than that of a hollow square section having the same plate thickness and the same moment of inertia in a hollow circular section.
Here, since the proof stress of the steel cross section is a value obtained by multiplying the cross-sectional primary moment by the material strength, having the same cross-sectional primary moment has the same meaning as making the proof strength the same.

  If the advantage of the hollow circular cross section with respect to this hollow square cross section is utilized, even if the steel pipe pile construction position is shifted as shown in FIG. That is, the embedded pillar 2a can be apparently reduced in diameter without reducing the proof stress. For this reason, the joining operation | work of the pillar 2 and the steel pipe pile 1 becomes easy. Here, the advantage of using a hollow circular cross section as the embedded column 2a has been described. However, if the embedded column 2a has a solid circular cross section that can easily ensure the yield strength, the diameter can be further reduced. I can plan. In other words, regardless of the steel pipe cross-sectional shape of the embedded column used, when the embedded column is hollow, it is preferable to fill it with concrete, mortar, or the like to make it solid.

  In this example, the column 2 and the embedded column 2a are made of steel. However, it is needless to say that other materials may be used as long as the design requirements are satisfied. The same applies to other embodiments described later.

Embodiment 2. FIG.
FIG. 6 is a longitudinal sectional view schematically showing an example of a column-pile joint structure according to Embodiment 2 of the present invention, and FIG. 7 is a longitudinal sectional view schematically showing another example. Portions corresponding to those in FIG. 1 and FIG. 2 of the first embodiment are given the same reference numerals.

  The column / pile joint structure of the second embodiment comprises a steel column 2 of a structure, a steel pipe pile 1 standing in the ground, and a steel foundation beam 4 that supports the lowest floor of the structure. The point which joined via the mouth member 10 differs from the thing of above-mentioned Embodiment 1. FIG. That is, the steel joint member 10 includes a column joint portion 2A to which the column 2 is joined, a beam joint portion 4A to which the steel foundation beam 4 is attached and joined in the horizontal direction, and a pile head 1a of the steel pipe pile 1. The embedded column 2a is inserted into and fixed with concrete, and the maximum outer diameter of the cross section of the embedded column 2a is set smaller than the maximum outer diameter of the cross section of the column joint 2A. Further, the steel foundation beam 4 is set to have a rigidity equal to or less than twice the rigidity of the upper beam (excluding 0), as in the first embodiment. The column 2 and the column joint 2A are joined by welding, and the steel foundation beam 4 and the beam joint 4A are joined by bolts or welding, respectively. The other configuration in which the closed lid 6 and the transition portion from the column 2 to the embedded column 2a are formed in a stepped cylindrical step or a taper (or inclined surface) 2b is the same as that shown in FIG. It is the same as that of FIG.

  That is, the rigidity of the steel foundation beam 4 and the beam joint 4A is also limited to a rigidity that is not more than twice the rigidity of the upper beam (excluding 0), thereby the relative moment Mpt of the embedded column 2a. Is reduced, and the diameter of the embedded pillar 2a is reduced.

  Therefore, also in the second embodiment, as in the first embodiment, it is easy to secure a margin for inserting the embedded column 2a into the steel pipe pile head 1a. Steel pipe piles with a pile diameter as designed can be used.

Embodiment 3 FIG.
8 to 10 are explanatory diagrams for explaining the column-pile joint structure according to Embodiment 3 of the present invention. FIG. 8 is a diagram illustrating the moment and plastic hinge (reference symbol J 9 is an explanatory diagram of the pile head displacement when the foundation beam is a small cross section, and FIG. 10 is an explanation of the pile head displacement when the foundation beam is a cross section of the upper beam (second floor beam) or more. FIG.

  In the first embodiment and the second embodiment described above, the rigidity of the steel foundation beam 4 or the rigidity of the steel foundation beam 4 and the beam joint 4A is limited to a rigidity equal to or less than twice the rigidity of the upper beam. The relative moment Mpt of the embedded column 2a is reduced to reduce the diameter of the embedded column 2a. In that sense, it is meaningful to define the upper limit value of the rigidity of the steel foundation beam 4 or the rigidity of the steel foundation beam 4 and the beam joint 4A. On the other hand, when the steel foundation beam is designed to have a rigidity that is less than 1 times that of the directly above beam (second floor beam), that is, a smaller cross section than the second floor beam, the steel foundation beam and its pile head with low section performance as shown in FIG. The joint yields before the top beam (2nd floor beam) and becomes a plastic hinge J. As a result, the moment in the middle of the pile is increased, and the pile head displacement increases as shown in FIG. It is conceivable that the interlayer deformation of the floor (the first floor in the figure) increases. The problem of insufficient rigidity of the pile can be solved by increasing the cross-sectional performance of the pile, but in this case, the material cost is increased, which is not preferable.

  Therefore, in the column-pile joint structure of the third embodiment, the lower limit value of the rigidity of the steel foundation beam 4 described in the first embodiment or the steel foundation beam 4 described in the second embodiment. The lower limit value of the rigidity of the beam joint 4A is defined, and the rigidity is set to be 2 times or less and 1 time or more of the rigidity of the directly above beam (second-floor beam). Thereby, the increase of pile head displacement can be suppressed like FIG. 10, ensuring the rigidity of a pile. As in the first and second embodiments described above, the diameter of the embedded column 2a can be reduced, and it is easy to secure a margin for inserting the embedded column 2a into the steel pipe pile head 1a. Steel pipe piles with the same pile diameter as the structural design can be used in the 1 pile integrated construction method.

Embodiment 4 FIG.
FIG. 11 is a longitudinal sectional view schematically showing an example of a column-pile joint structure according to Embodiment 4 of the present invention, and FIG. 12 is a longitudinal sectional view schematically showing another example. Parts corresponding to those in FIGS. 1 and 2 of the first embodiment and FIGS. 6 and 7 of the second embodiment are denoted by the same reference numerals.

  In this fourth embodiment, the pillar-to-pile joint structure is provided with a plurality of concentric protrusions 7 concentrically on the inner surface of the steel pipe pile head instead of the restraining ring 5 of the first and second embodiments. Other than that, the column 2, the embedded column 2 a, the steel foundation beam 4, the closing lid 6, and the transition part from the column 2 to the embedded column 2 a are stepped cylindrical or tapered (or inclined surface). The structure formed in 2b is the same as that of FIGS. 1 and 2 of the first embodiment and FIGS. 6 and 7 of the second embodiment.

  That is, the rigidity of the steel foundation beam 4 is limited to 2 times or less (excluding 0), preferably 1 to 2 times that of the directly above beam. Thereby, the relative moment Mpt of the embedded pillar 2a is reduced, and the diameter of the embedded pillar 2a is reduced.

  Therefore, also in this fourth embodiment, as in the first and second embodiments described above, it is easy to secure a margin for inserting the embedded column into the steel pipe pile head, and one pillar and one pile are integrated. In the chemical method, steel pipe piles with the same pile diameter as the structural design can be used.

In addition, the plurality of protrusions 7 provided on the inner surface of the steel pipe pile head increase the adhesion force of the concrete 3 and can prevent the shear splitting and tensile fracture of the concrete 3 and prevent brittle fracture of the joint. Can do. As a result, sufficient plastic deformation of the steel frame can be promoted.
Furthermore, by providing the protrusions 7 below the embedded columns, it is possible to transmit the vertical load acting on the embedded columns to the pile by the adhesion between the steel pipe and the concrete. The number of protrusions is arbitrary.
The closing lid 6 is for keeping the concrete 3 in the pile head when filling.

It is a longitudinal cross-sectional view which shows typically an example of the joining structure of the pillar and pile concerning Embodiment 1 of this invention. It is a longitudinal cross-sectional view which shows typically the other example of the joining structure of the pillar which concerns on Embodiment 1, and a pile. It is a graph which shows the relationship between the embedding column moment and the N value of the ground at the time of changing the rigidity of the foundation beam of the column-pile joint structure concerning Embodiment 1. FIG. It is explanatory drawing of the largest outer diameter dimension in the hollow circular cross section and hollow square cross section of the same board thickness and the same section modulus. It is explanatory drawing which shows the advantage of a hollow circular cross section with respect to a hollow square cross section in relation to a steel pipe pile. It is a longitudinal cross-sectional view which shows typically an example of the junction structure of the pillar and pile concerning Embodiment 2 of this invention. It is a longitudinal cross-sectional view which shows typically the other example of the junction structure of the pillar which concerns on Embodiment 2, and a pile. It is explanatory drawing of the junction structure of the pillar which concerns on Embodiment 3 of this invention, and a pile, and is a moment figure which a foundation beam too soft exerts on a pile. It is explanatory drawing of the junction structure of the pillar which concerns on Embodiment 3, and a pile head displacement at the time of making a foundation beam into a small cross section. It is explanatory drawing of the junction structure of the pillar which concerns on Embodiment 3, and is a pile head displacement figure at the time of making a foundation beam into a cross section more than a direct upper beam (2nd floor beam). It is a longitudinal cross-sectional view which shows typically an example of the joining structure of the pillar and pile concerning Embodiment 4 of this invention. It is a longitudinal cross-sectional view which shows typically the other example of the junction structure of the pillar which concerns on Embodiment 4, and a pile. It is explanatory drawing of the moment which a beam exerts on a pillar and a pile. It is explanatory drawing of the moment which a beam exerts on a pillar and a pile. It is explanatory drawing of the moment which a sufficiently rigid foundation beam exerts on a column and a pile. It is explanatory drawing of the moment which a soft rigid foundation beam exerts on a column and a pile. It is a graph which shows the relationship between the stress ratio of the column base moment and the embedded column moment of the column of the lowest floor, and the N value of the ground.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steel pipe pile 1a Pile head 2 Column 2a Embedded column 2A Column joint 3 Concrete 4 Steel foundation beam 4a Lower flange 4b Upper 1 flange 4A Beam joint 5 Restraint ring 7 Protrusion 10 Joint member

Claims (8)

The pillars of the structure,
Steel pipe piles standing in the ground,
A foundation beam supporting the structure;
It is a joint structure between a pillar and a pile consisting of an upper beam that supports the floor directly above the foundation beam,
The pillar is
Embedded pillars inserted into the pile head of the steel pipe pile and fixed with concrete;
A beam joint in which the foundation beam is joined in a horizontal direction to the column;
Furthermore, the maximum outer diameter dimension of the embedded column cross section is set to be smaller than the maximum outer diameter dimension of the intersection surface between the upper surface of the foundation beam and the column,
The foundation beam is
A column-pile joint structure characterized in that its rigidity is set to be twice or less (excluding 0) that of the beam directly above. The pillars of the structure,
Steel pipe piles standing in the ground,
A foundation beam supporting the structure;
An upper beam supporting the floor directly above the foundation beam;
At least a column joint part to which the pillar is joined, a beam joint part to which the foundation beam is attached and joined in a horizontal direction, and an embedded pillar that is inserted into a pile head of the steel pipe pile and fixed with concrete. It is a joining structure of a pillar and a pile made of a joint member having,
The joint member is
The maximum outer diameter dimension of the embedded column cross section is set smaller than the maximum outer diameter dimension of the cross section of the column joint,
The foundation beam and the beam joint are:
A column-pile joint structure characterized in that its rigidity is set to be twice or less (excluding 0) that of the beam directly above. The pillars of the structure,
Steel pipe piles standing in the ground,
A foundation beam supporting the structure;
It is a joint structure between a pillar and a pile consisting of an upper beam that supports the floor directly above the foundation beam,
The pillar is
Embedded pillars inserted into the pile head of the steel pipe pile and fixed with concrete;
A beam joint in which the foundation beam is joined in a horizontal direction to the column;
Furthermore, the maximum outer diameter dimension of the embedded column cross section is set to be smaller than the maximum outer diameter dimension of the intersection surface between the upper surface of the foundation beam and the column,
The foundation beam is
The column-pile joint structure is characterized in that its rigidity is set to be 2 times or less and 1 time or more of the rigidity of the overhead beam. The pillars of the structure,
Steel pipe piles standing in the ground,
A foundation beam supporting the structure;
An upper beam supporting the floor directly above the foundation beam;
At least a column joint part to which the pillar is joined, a beam joint part to which the foundation beam is attached and joined in a horizontal direction, and an embedded pillar that is inserted into a pile head of the steel pipe pile and fixed with concrete. It is a joining structure of a pillar and a pile made of a joint member having,
The joint member is
The maximum outer diameter dimension of the embedded column cross section is set smaller than the maximum outer diameter dimension of the cross section of the column joint,
The foundation beam and the beam joint are:
The column-pile joint structure is characterized in that its rigidity is set to be 2 times or less and 1 time or more of the rigidity of the overhead beam.   The column-pile joint structure according to any one of claims 1 to 4, wherein a cross-section of the embedded column is a hollow circular cross-section.   The column-pile joint structure according to any one of claims 1 to 4, wherein the embedded column has a solid circular cross section.   The column and pile joint structure according to any one of claims 1 to 6, wherein an extraction restraining ring for the embedded column is installed on the steel pipe pile head. The column-pile joint structure according to any one of claims 1 to 6, wherein a plurality of protrusions are provided on an inner surface of the steel pipe pile head.

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