JP2012007651A - Non-welded steel pipe joint and method of joining steel pipes - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-welded steel pipe joint which can be worked easily because of the simple structure, can suppress degradation of bearing force and rigidity of a joint part, as well as improve its appearance by compacting the structure.SOLUTION: A joint 1 includes an inner steel pipe 20 having a mortar injection part 23 which is divided liquid tightly by upper and lower partition walls 21 and 22 in the end part of an upper column 2 at one side, and an outer steel pipe 30 having a larger inner diameter than the inner steel pipe 20 disposed at the end part of a lower column 3 at the other side. In a state where the inner steel pipe 20 is inserted coaxially in the outer steel pipe 30, the inner steel pipe 20 is expanded by injecting an expandable mortar 4 to the mortar injection part 23, so that the inner steel pipe 20 and the outer steel pipe 30 are frictionally joined.

Description

  The present invention relates to a non-welded steel pipe joint and a steel pipe joining method used for joining steel pipe columns and the like of buildings.

  Conventionally, in a construction site of a steel building, it is common to join steel pieces that are divided and carried in by high-strength bolts or on-site welding. And when a joining object is a steel pipe, since it is a closed cross section, it is difficult to employ | adopt joining by a high strength volt | bolt, and there exists the present condition which must implement on-site welding. However, in the case of on-site welding, the quality of welding and the presence or absence of defects depend largely on the ability of the welding engineer, and depending on the welding operation, it is affected by temperature and climate, and there are many quality control items, resulting in high costs. Yes.

On the other hand, a mechanical type using a bolt is known as a non-welded steel pipe joint. This mechanical joint is used for embedded piles, and is also applicable to steel pipes with a small cross section for residential use. The joint section has a small bending strength and has a complicated structure.
Further, as another non-mechanical welded steel pipe joint, as shown in FIG. 15, an outer steel pipe 102 is disposed at a connection portion between the steel pipes 100 and 101, and an expansion mortar 103 is provided between the steel pipes 100 and 101 and the outer steel pipe 102. There is a joint structure in which the adhesive strength of the expanding mortar and compression struts are used, and this is also disclosed in Patent Document 1, for example.

  In Patent Document 1, a water-stopping material is provided at the end of the steel pipe facing the pipe ends of the steel pipe (inner steel pipe) adjacent to each other, the outer periphery of the joint portion of the steel pipe is covered, and flange portions are provided on both inner sides. A separable cylindrical outer pipe (outer steel pipe) is placed on the steel pipe, a water-stopping material is placed between the flange and the outer pipe, and a predetermined expansion occurs in the joint space formed by the outer pipe and the steel pipe. A non-welded steel pipe joint filled with expanded mortar that produces pressure is disclosed.

Japanese Patent Laid-Open No. 9-79447

However, the conventional non-welded steel pipe joint has the following problems.
That is, in Patent Document 1, a thickness dimension is required between the inner steel pipe and the outer steel pipe so that adhesion strength due to expansion mortar and compression struts can be generated, which increases the outer diameter dimension of the outer steel pipe. There was a problem of getting worse. And there exists such a problem on an external appearance, and the fault that the structure by the non-welded steel pipe joint by a mechanical type mentioned above becomes complicated, The non-welded steel pipe joint which can solve these with sufficient balance is calculated | required.
Moreover, in patent document 1, since the yield strength as a joint is determined by the adhesion yield strength between a mortar and a steel pipe, there existed the problem of quality that a yield strength became low and an inner steel pipe buckled by expansion | swelling of the mortar.

The present invention has been made in view of the above-described problems, and provides a non-welded steel pipe joint and a steel pipe joining method that can be easily constructed with a simple structure and can suppress a decrease in yield strength and rigidity of the joint. The purpose is to do.
Another object of the present invention is to provide a non-welded steel pipe joint and a steel pipe joining method capable of improving the appearance by adopting a compact structure.

  In order to achieve the above object, in the non-welded steel pipe joint according to the present invention, the end parts of a pair of steel pipes are arranged so as to face each other and joined, and in the end part of one of the first steel pipes, An inner steel pipe having a filling chamber partitioned liquid-tightly by a partition wall is provided, and an end of the other second steel pipe is provided with an outer steel pipe having a larger inner diameter than the inner steel pipe, and the inner steel pipe is coaxial with the outer steel pipe. In the inserted state, the inner steel pipe is expanded by injecting an inflatable filler into the filling chamber, and the inner steel pipe and the outer steel pipe are frictionally joined.

  The steel pipe joining method according to the present invention is a steel pipe joining method for joining a pair of steel pipes whose ends are opposed to each other by a non-welded steel pipe joint, and a partition wall is provided in the end of one first steel pipe. A step of providing an inner steel pipe having a filling chamber partitioned liquid-tightly by the step, a step of providing an outer steel pipe having an inner diameter larger than the inner steel pipe at the end of the other second steel pipe, and an inner steel pipe as an outer steel pipe It is characterized by having a step of inserting coaxially and a step of injecting a filler having an expandability into the filling chamber, expanding the inner steel pipe, and frictionally joining the inner steel pipe and the outer steel pipe.

In the present invention, when the filler is injected into the filling chamber of the inner steel pipe while the inner steel pipe is inserted into the outer steel pipe, the filling chamber is partitioned liquid-tightly by the partition wall, so that the expansion of the filler in the filling chamber is performed. Due to the action, the inner steel pipe swells outward and comes into contact with the inner surface of the outer steel pipe. If the expansion further continues, contact pressure is generated between the inner steel pipe and the outer steel pipe, and the friction caused by this contact pressure counters the axial tensile force and bending moment acting between the inner steel pipe and the outer steel pipe. It will be. That is, the restraining pressure of the outer steel pipe with respect to the inner steel pipe is sufficiently ensured, both the steel pipes are integrally joined, and the pair of the first steel pipe and the second steel pipe are joined by the non-welded steel pipe joint. Become.
Moreover, since the filler is filled in the joint portion, the steel pipe in the joint portion does not buckle.

In addition, construction on site is an extremely simple task of simply injecting filler into the filling chamber, so that construction efficiency can be improved, and because it is a welded joint without welding, defects caused by field welding are less likely to occur. Quality can be ensured.
Furthermore, since it is not necessary to inject and join a filler between the inner steel pipe and the outer steel pipe, the outer steel pipe only needs to have an inner diameter dimension sufficient to insert the inner steel pipe inside thereof. In other words, since the interval between the inner steel pipe and the outer steel pipe can be reduced or set to be almost in contact with each other, the outer structure of the outer steel pipe can be reduced and the appearance can be improved and the arrangement can be improved. There are no restrictions.

In the unwelded steel pipe joint according to the present invention, it is preferable that a groove is provided on at least one of the inner peripheral surface and the outer peripheral surface of the inner steel pipe.
In the present invention, by providing a groove in the inner steel pipe, the cross-sectional area is reduced, so that the inner steel pipe is easily deformed radially outward by the filler, and the restraining pressure of the outer steel pipe with respect to the inner steel pipe is further increased. Can do.

In the unwelded steel pipe joint according to the present invention, the groove may extend along the axial direction of the inner steel pipe.
In this case, by arranging grooves extending in the axial direction of the inner steel pipe at regular intervals along the circumferential direction, the inner steel pipe can be uniformly expanded radially outward in the circumferential direction, and a balanced joint can be obtained. Can be realized.

In the non-welded steel pipe joint according to the present invention, the groove may extend along the circumferential direction of the inner steel pipe.
In this case, it is possible to positively inflate a part of the inner steel pipe in the axial direction by a groove along the circumferential direction provided in the inner steel pipe.

Further, in the non-welded steel pipe joint according to the present invention, the inner peripheral surface of the outer steel pipe has the central portion positioned radially outermost in the material axis direction, and gradually increases as the inner steel pipe is separated from the central portion on both sides of the central portion. It is more preferable that a tapered portion that is closer to the outer peripheral surface is formed.
In the present invention, the inner steel pipe can be deformed following the tapered portion of the outer steel pipe. At this time, a wedge action that is joined to the outer steel pipe in a state in which the central portion of the inner steel pipe in the axial direction protrudes radially outwardly works, and the tensile shaft strength acting between the inner steel pipe and the outer steel pipe And bending strength can be improved.

Moreover, in the non-welded steel pipe joint according to the present invention, it is preferable that at least one of the outer peripheral surface of the inner steel pipe and the inner peripheral surface of the outer steel pipe is subjected to a treatment for increasing friction.
In the present invention, at least one of the outer peripheral surface of the inner steel pipe and the inner peripheral surface of the outer steel pipe is subjected to blasting, red rust, or the like, thereby increasing the slip coefficient and reducing the friction between the inner steel pipe and the outer steel pipe expanded by the filler. The contact pressure can be increased by increasing the contact pressure.

According to the non-welded steel pipe joint and the steel pipe joining method of the present invention, the inner steel pipe swells radially outward by the filler injected into the filling chamber to generate a contact pressure with respect to the outer steel pipe. Since the restraint pressure of the steel pipe can be sufficiently secured and the both steel pipes are integrally joined, it is possible to suppress a decrease in yield strength and rigidity of the joint portion.
Moreover, since it is a simple structure which inject | pours a filler into the filling chamber of an inner steel pipe, there exists an advantage which construction becomes easy.
Furthermore, there is no need to provide a sufficient space between the inner steel pipe and the outer steel pipe to fill the filler, and the outer diameter of the outer steel pipe can be suppressed, so that a compact joint structure can be realized and the appearance can be improved. The effect which can be done is produced.

It is a partially broken perspective view which shows the coupling part by the 1st Embodiment of this invention. It is a sectional side view of the joint part shown in FIG. It is the sectional view on the AA line shown in FIG. It is a sectional side view for demonstrating the effect | action of a joint part, Comprising: As shown in FIG. 2, it is a figure corresponding. It is a sectional side view for demonstrating the effect | action of a coupling part similarly, Comprising: As shown in FIG. 2, it is a figure corresponding. FIG. 6 is a sectional view taken along line B-B shown in FIG. 5. It is a sectional side view which shows the coupling part by 2nd Embodiment. It is a sectional side view which shows the coupling part by a 1st modification. It is a sectional side view which shows the coupling part by a 2nd modification. It is a figure which shows the yield characteristic of the steel materials by an Example. It is a graph which shows the yield characteristic of the steel materials by an Example. It is a sectional side view which shows the injection | pouring method of another expansion mortar, Comprising: It is a figure corresponding to FIG. It is a partially broken perspective view which shows the injection | pouring method of another expansion mortar, Comprising: It is a figure corresponding to FIG. It is a sectional side view which shows the injection | pouring method of another expansion mortar, Comprising: It is a figure corresponding to FIG. It is a figure which shows the non-welded steel pipe joint using the conventional expansion mortar.

  Hereinafter, a non-welded steel pipe joint and a steel pipe joining method according to a first embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the non-welded steel pipe joint (hereinafter simply referred to as “joint part 1”) according to the first embodiment is made of a cylindrical steel pipe column used in a steel building without welding. It is used when joining in series in the axial direction.
Here, reference numeral 2 in FIG. 1 indicates an upper column (first steel pipe), and reference numeral 3 indicates a lower column (second steel pipe). The upper column 2 and the lower column 3 have the same outer diameter, and the lower end of the upper column 2 and the upper end of the lower column 3 are arranged to face each other on the coaxial line and are joined by the joint portion 1.

  As shown in FIG. 1 and FIG. 2, flat partition walls 21 and 22 are provided at predetermined intervals in the vertical direction at the lower part of the upper column 2, and the wall surface direction is set to the vertical axis O <b> 1 of the upper column 2. They are arranged in a horizontal direction perpendicular to the direction. An expandable mortar 4 (filler) having expandability is injected into a mortar injection portion 23 (filling chamber) partitioned liquid-tightly by a pair of upper and lower partition walls 21 and 22.

The lower lower partition wall 21 is located at the lower end 2a of the upper column 2, and its outer peripheral edge 21a is fixed to the upper column 2 in a liquid-tight state by welding.
The upper upper partition wall 22 is positioned above the lower partition wall 21 in the inner space of the upper column 2 with the predetermined interval, and its outer peripheral edge 22a is liquid-tight by welding to the inner peripheral surface 2b of the upper column 2. It is fixed in the state. The upper partition wall 22 is provided with an injection hole 24 for the expansion mortar 4 penetrating in the thickness direction.

  Here, a portion of the upper column 2 located below the upper partition wall 22 (that is, a portion corresponding to the mortar injection portion 23) is hereinafter referred to as an inner steel pipe 20.

  The inner steel pipe 20 is provided with an appropriate number of deaeration holes 25 (FIG. 2) penetrating in the thickness direction of the steel pipe at a position immediately below the upper partition wall 22. This deaeration hole 25 is an air vent hole for replacing the air inside when the expansion mortar 4 is filled into the mortar injection part 23 from the injection hole 24.

As shown in FIGS. 1 and 3, the lower column 3 is provided with an outer steel pipe 30 having an inner diameter larger than the outer diameter of the inner steel pipe 20 at the upper end 3a on the axis O1. Specifically, a circular plate 31 having the same outer diameter as the outer steel pipe 30 is welded to the upper end 3a of the lower column 3, and the lower end 30a of the outer steel pipe 30 is brought into contact therewith and fixed by welding.
The inner steel pipe 20 of the upper column 2 can be inserted into the outer steel pipe 30. And the height dimension of the outer steel pipe 30 is formed in the length dimension which can overlap with the said inner steel pipe 20. As shown in FIG.

  Further, the inner steel pipe 20 and the outer steel pipe 30 are arranged in a contacted state or a state having a slight gap s (FIG. 3).

  1 and FIG. 2, the inner steel pipe 20 is coaxially fitted in the outer steel pipe 30, and the mortar of the inner steel pipe 20 is disposed so as to surround the inner steel pipe 20 by the outer steel pipe 30. The injecting portion 23 is densely filled with the expanded mortar 4. At this time, the lower end 20 a of the inner steel pipe 20 is brought into contact with the circular plate 31 of the outer steel pipe 30, and the lower column 3 supports the upper column 2 including the inner steel tube 20.

Next, the effect | action of the coupling part 1 comprised in this way is demonstrated based on drawing.
As shown in FIG. 4, when the expanded mortar 4 is injected into the mortar injection portion 23 of the inner steel pipe 20 with the inner steel pipe 20 inserted into the outer steel pipe 30, the mortar injection portion 23 is liquidated by the lower partition wall 21 and the upper partition wall 22. The inner steel pipe 20 swells outward with a predetermined expansion pressure (reference numeral F1 in FIG. 4) due to the expansion action of the expansion mortar 4 in the mortar injecting portion 23 and closes against the inner surface of the outer steel pipe 30. Will be in touch.
As shown in FIG. 5, when the expansion further continues, a contact pressure is generated between the inner steel pipe and the outer steel pipe 30, and a shaft acting between the inner steel pipe 20 and the outer steel pipe 30 due to friction caused by the contact pressure. It will counter the tensile force and bending moment in the direction. That is, the restraining pressure (reference numeral F2 in FIG. 5) of the outer steel pipe 30 with respect to the inner steel pipe 20 is sufficiently secured, and both the steel pipes 20 and 30 are integrally joined. The pillar 3 is joined. Moreover, since the expansion mortar 4 is filled in the joint part 1, the steel pipe in the joint part 1 does not buckle.

In addition, the mechanical balance in the joint part 1 is the friction force (FIG. 5) which generate | occur | produces between the expansion pressure F1 of the expansion mortar 4 shown to (1) Formula, and the inner steel pipe 20 and the outer steel pipe 30 shown to (2) Formula. Is determined by the code F3).
Expansion pressure = Restraint pressure of the inner steel pipe + Restraint pressure of the outer steel pipe (1)
Friction force = slip coefficient x outer steel pipe restraint pressure x contact area (2)

  Further, in the equation (2), in order to increase the slip coefficient, a treatment for increasing friction such as blasting or generating red rust may be performed on the outer side of the inner steel pipe 20 and the inner side of the outer steel pipe 30.

In addition, on-site construction is an extremely simple task of simply injecting the expanded mortar 4 into the mortar injecting portion 23, so that the construction efficiency can be improved, and because it is a non-welded joint, defects due to on-site welding are less likely to occur. Can ensure excellent quality.
Furthermore, since it is not necessary to inject and join the expansion mortar 4 between the inner steel pipe 20 and the outer steel pipe 30, the outer steel pipe 30 only needs to have an inner diameter dimension that allows the inner steel pipe 20 to be inserted therein. . That is, as shown in FIG. 6, the distance s (FIG. 3) between the inner steel pipe 20 and the outer steel pipe 30 can be reduced or set in a substantially contacted state. It becomes a structure, the appearance can be improved, and there is no restriction on the arrangement.

As described above, in the non-welded steel pipe joint and the steel pipe joining method according to the first embodiment, the inner steel pipe 20 is expanded radially outward by the expanded mortar 4 injected into the mortar injection portion 23 with respect to the outer steel pipe 30. Since the contact pressure is generated, and the restraining pressure of the outer steel pipe 30 with respect to the inner steel pipe 20 can be sufficiently secured, and the both steel pipes 20 and 30 are joined together, the strength and rigidity of the joint portion can be reduced. The decrease can be suppressed.
Moreover, since it is a simple structure which inject | pours the expansion mortar 4 into the mortar injection | pouring part 23 of the inner steel pipe 20, there exists an advantage which construction becomes easy.
Furthermore, there is no need to provide a sufficient interval between the inner steel pipe 20 and the outer steel pipe 30 so as to fill expansion mortar, and the outer diameter of the outer steel pipe 30 can be suppressed, so that a compact joint structure can be realized. There is an effect that the appearance can be improved.

  Next, other embodiments and modifications of the non-welded steel pipe joint and steel pipe joining method of the present invention will be described with reference to the accompanying drawings, but the same or similar members and parts as those of the first embodiment described above. The same reference numerals are used to omit the description, and a configuration different from that of the first embodiment will be described.

  As shown in FIG. 7, the non-welded steel pipe joint (joint portion 1 </ b> A) according to the second embodiment is arranged in the vertical direction on the outer peripheral surface of the inner steel pipe 20 or the inner peripheral surface (the outer peripheral surface 20 b in FIG. 7). It is the structure which provided the vertical groove | channel 26 extended along (the axial direction of a pillar). The longitudinal grooves 26 are provided over almost the entire length in the material axis direction (height dimension) of the inner steel pipe 20, and a plurality of the longitudinal grooves 26 are provided in the circumferential direction of the inner steel pipe 20 with a constant interval.

In the joint portion 1A according to the second embodiment, since the cross-sectional area of the inner steel pipe 20 is reduced by the plurality of longitudinal grooves 26, 26,..., The radially outer side of the inner steel pipe 20 due to the expansion of the expansion mortar 4 occurs. It becomes easy to deform | transform and it becomes possible to raise the restraint pressure of the outer steel pipe 30 with respect to the inner steel pipe 20 more.
On the other hand, since the frictional force in the axial direction and the reduction in the cross section of the steel material can be minimized, the frictional force can be increased, which is effective.
Moreover, in this case, by arranging the longitudinal grooves 26 extending in the axial direction of the inner steel pipe 20 at a constant interval along the circumferential direction, the inner steel pipe 20 can be uniformly expanded radially outward in the circumferential direction, A well-balanced joint can be realized.

  Moreover, as shown in FIG. 8, the non-welded steel pipe joint (joint part 1B) by a 1st modification is extended over the perimeter to the outer peripheral surface of the inner steel pipe 20, or an inner peripheral surface (in FIG. 7, outer peripheral surface 20b). The lateral groove 27 is provided at a substantially intermediate position in the material axis direction (height direction) of the inner steel pipe 20, and the outer steel pipe 30 is provided with a vertex 30b that protrudes radially outward at a position facing the lateral groove 27, and the vertex 30b. The taper parts 30c and 30c which gradually approach the outer peripheral surface of the inner steel pipe 20 are formed as it leaves | separates from up to down.

In this case, it is possible to positively inflate part of the inner steel pipe 20 in the material axis direction by the lateral grooves 27 along the circumferential direction provided in the inner steel pipe 20.
Further, the inner steel pipe 20 can be deformed following the tapered portion 30 c of the outer steel pipe 30. At this time, a wedge action that is joined to the outer steel pipe 30 in a state in which the central portion in the axial direction of the inner steel pipe 20 protrudes radially outwardly acts, and acts between the inner steel pipe 20 and the outer steel pipe 30. It is possible to improve the tensile shaft strength and bending strength.

Moreover, the unwelded steel pipe joint (joint part 1C) by the 2nd modification shown in FIG. 9 has the cylindrical part 30d in the intermediate part of the up-down direction in the outer steel pipe 30, and is each on the upper and lower sides of the cylindrical part 30d. The taper portions 30c and 30c are provided. The inner steel pipe 20 is provided with lateral grooves 27 (27A, 27B) at regular intervals in the vertical direction at positions corresponding to the connecting portions between the cylindrical portion 30d and the tapered portions 30c, 30c.
Also in the joint portion 1C of the second modified example, the tensile shaft strength and the bending strength can be improved by the wedge effect by the taper as in the first modified example described above.

  Next, calculation examples performed to support the joining effect of the unwelded steel pipe joint according to the above-described embodiment will be described below.

First, the internal pressure required to plasticize the steel pipe in the circumferential direction is calculated.
Here, in order to simplify the calculation, as the shape of the inner steel pipe of SS400, the outer diameter is 400 mm, and the thickness dimension (plate thickness) is 12 mm.
As shown in FIG. 10, the axial stress σ ₁ and the circumferential stress σ _2, which are the degrees of stress generated in the cylindrical shell, are obtained from the equations (3) and (4), respectively. Here, p in the formula is the internal pressure, r is the radius of the steel pipe, and t is the plate thickness of the steel pipe.
σ ₁ = rp / 2t (3)
σ ₂ = rp / t (4)

Next, the clearance between the inner steel pipe and the outer steel pipe will be examined.
If the yield stress of sigma _y of the steel tube was 235N / mm ^2, the pressure required for plasticization of the steel pipe, (5) by the fact that the 14N / mm ^2, the pressure required for plasticization with expansion concrete It is fully possible to realize.
The expansion pressure of the expansion mortar is 49 N / mm ² or more (after 48 hours) (from the catalog of Pacific Materials).
P = tσ ₂ / r (5)

When the expansion pressure P due to the expanded concrete is 30 N / mm ² , the degree of stress generated in the circumferential direction of the inner steel pipe is 500 N / mm ² from the equation (6).
σ ₂ = rp / t (6)

The breakdown characteristics of the steel by bilinear ^{_{(σ y = 235N / mm 2}} , Young's modulus E = 205000N / mm ^2, the Young's modulus of the second fold line E'= E / 200), assuming as shown in FIG. 11, the steel pipe As for the degree of distortion in the circumferential direction, the degree of distortion ε _y up to the yield point is 0.001146 (1146 μ) from the expression (7), and the degree of distortion Δε after the yield point is 0.063415 from the expression (8). Therefore, from equation (9), ε ₂ is 0.064561.
ε _y = σ _y / E (7)
Δε = Δσ / E ′ = (σ ₂ −σ _y ) / E ′ (8)
ε ₂ = ε _y + Δε (9)

Furthermore, if the initial radius of the steel pipe is r and the radius after expansion is r ′, the difference in length in the circumferential direction before and after expansion is expressed by equation (10). Therefore, the increment of the steel pipe diameter due to expansion is 25.8 mm from the equation (11).
2π (r′−r) = 2πr × ε ₂ (10)
2 (r′−r) = 2πr × ε ₂ (11)
In addition, if the difference of the inner diameter of an outer steel pipe required for construction and the outer diameter of an inner steel pipe is 10 mm, it can be confirmed that the inner steel pipe and the outer steel pipe are sufficiently adhered to each other by the expansion of the inner steel pipe under the above conditions.

Further, stress is transmitted by metal touch to the compression axial force of the joint.
On the other hand, since the outer column of the receiving side column is reinforced with an outer steel pipe, it can be handled as a nearly strong joint without causing buckling.

Next, the tensile axial force of the joint is resisted by the frictional resistance of the entire circumference of the inner steel pipe that overlaps the outer steel pipe. In the unlikely event that a tensile axial force greater than the frictional strength is generated, the overlap portion is present, so that the joint portion does not deviate in the axial direction or deviate out of plane.
Here, although the specific example of the tensile-axis proof stress by friction is shown, in order to simplify, the outer steel pipe of inner diameter (phi) 410mm is assumed with respect to the inner steel pipe of outer diameter 400mm x thickness dimension 12mm. If the overlap length of the steel pipe contact surface is 450 mm, the restraining pressure p of the outer steel pipe is 20 N / mm ² , and the slip coefficient is μ = 0.4, 4645 kN is obtained from the equation (12).
Q _f = μpA (12)
In addition, the joining of the outer steel pipe of the receiving side steel pipe is a welded joint designed with sufficient strength against the tensile axial force.

  Moreover, since it resists in the cross section of an outer steel pipe with respect to the shearing force of a joint part, it can be handled as a nearly all strong joint.

In addition, with respect to the bending moment of the joint portion, since the inside is filled with expanded concrete, an effect of preventing the joint portion from being crushed by bending (planar holding) can be expected.
When the friction resistance of the joint is insufficient, the length of the overlap and the expansion pressure are increased or the taper is attached to prevent the flange from being pulled out.
In this regard, for the sake of simplicity, a square steel pipe having a size of 400 mm × 400 mm and a thickness of 12 mm is assumed. In addition, since the compression axial force of a column works on the safe side, it shall not be considered here.
If the yield strength sigma _y of the square tube and 235N / mm ^2, yield moment _{M y} pillar becomes 550kNm than (13). Z is a section modulus.
M _y = σ _y Z (13)

Furthermore, if the frictional force generated in the joint face is Q _f and the columnarity is h, the bending moment M _f borne by the flange joint is expressed by the equation (14).
M _f = Q _f h (14)
Here, if the overlap length of the steel pipe contact surface is 450 mm, the restraining pressure p of the outer steel pipe is 20 N / mm ² , and the slip coefficient μ is 0.4, the frictional force Q _f generated on the joint face is 1440 kN, From the equation (14), the bending moment _Mf is 576 kNm.
Therefore, it is possible to design with full strength against the yield bending moment of the column.

As mentioned above, although embodiment of the non-welded steel pipe joint and steel pipe joining method by this invention was described, this invention is not limited to said embodiment, It can change suitably in the range which does not deviate from the meaning. .
For example, in the present embodiment, the steel pipes constituting the upper column 2 and the lower column 3 have a circular cross section. However, the present invention is not limited to this shape, and may be a square or hexagonal steel pipe. Absent. Similarly, the inner steel pipe 20 and the outer steel pipe 30 are not limited to the circular cross section.

Moreover, in this Embodiment, although the expansion mortar 4 is employ | adopted as a material inject | poured into the filling chamber (mortar injection | pouring part 23) of the inner steel pipe 20, it is not restricted to this, For example, the concrete which has expansibility may be sufficient. Absent.
Further, the overlap length in the axial direction of the inner steel pipe 20 and the outer steel pipe 30, the distance between the inner steel pipe 20 and the outer steel pipe 30, the thickness dimension of the outer steel pipe 30, and the distance between the longitudinal groove 26 and the lateral groove 27, position, outer The configuration such as the inclination angle of the tapered portion 30c of the steel pipe 30 can be appropriately set according to the size of the steel pipe (upper column 2 and lower column 3), the amount of expansion of the inner steel tube 20, and the like.

Further, the method for injecting the expanded mortar 4 is not limited to the above-described embodiment, and an appropriate method can be adopted. For example, as shown in FIG. There is a method in which the injection pipe 5 is connected to the injection hole 24 from the upper side of the column beam joint T, and the expansion mortar 4 is injected into the mortar injection part 23 of the inner steel pipe 20 using the injection pipe 5.
Further, as shown in FIG. 13, a side hole 28 is provided on the side surface of the upper column 2, and an injection pipe 6 connected from the side hole 28 to the injection hole 24 of the upper partition wall 22 is provided. There is also a method of injecting the expanded mortar 4 into the mortar injecting portion 23 of the inner steel pipe 20 using.
Furthermore, as shown in FIG. 14, the expansion mortar 4 is injected into the mortar injection portion 23 from the injection hole 7 disposed at the same position as the deaeration hole 25 of the inner steel pipe 20, and the expansion mortar 4 extends from the deaeration hole 25. It may be a method of injecting until it overflows.
In filling the expanded mortar 4 into the mortar injecting portion 23 (filling chamber), the mortar is preferably in close contact with the upper partition wall 22, but even if a slight gap occurs, the gap disappears due to the expansion of the mortar. On the other hand, when the length of the filling chamber in the material axis direction is longer than the overlap length, the mortar expands three-dimensionally even if a slight gap is generated between the upper partition wall 22 and the mortar. The inner steel pipe 20 expands outward.

1, 1A, 1B, 1C Joint part (non-welded steel pipe joint)
2 Upper column (first steel pipe)
3 Lower pillar (second steel pipe)
4 Expansion mortar (filler)
20 Inner steel pipe 21 Lower partition wall 22 Upper partition wall 23 Mortar injection part (filling chamber)
26 Longitudinal groove 27 Horizontal groove 30 Outer steel pipe 30c Taper part

Claims (7)

It is a non-welded steel pipe joint that joins the ends of a pair of steel pipes facing each other,
In one end of the first steel pipe, an inner steel pipe having a filling chamber partitioned liquid-tightly by a partition wall is provided.
An end of the other second steel pipe is provided with an outer steel pipe having an inner diameter larger than that of the inner steel pipe,
With the inner steel pipe coaxially inserted into the outer steel pipe, the inner steel pipe is expanded by injecting an inflatable filler into the filling chamber, and the inner steel pipe and the outer steel pipe are frictionally joined. A welded steel pipe joint characterized by having a configuration.   The non-welded steel pipe joint according to claim 1, wherein a groove is provided on at least one of the inner peripheral surface and the outer peripheral surface of the inner steel pipe.   The unwelded steel pipe joint according to claim 2, wherein the groove extends along an axial direction of the inner steel pipe.   The unwelded steel pipe joint according to claim 2, wherein the groove extends along a circumferential direction of the inner steel pipe.   The inner peripheral surface of the outer steel pipe has a central portion located radially outermost in the material axis direction, and tapered portions that gradually approach the outer peripheral surface of the inner steel pipe are formed on both sides of the central portion as the distance from the central portion increases. The non-welded steel pipe joint according to any one of claims 1 to 4, wherein the steel pipe joint is not welded.   The non-welded steel pipe joint according to any one of claims 1 to 5, wherein a treatment for increasing friction is applied to at least one of the outer peripheral surface of the inner steel pipe and the inner peripheral surface of the outer steel pipe. A steel pipe joining method for joining a pair of steel pipes whose ends are opposed to each other by a non-welded steel pipe joint,
A step of providing an inner steel pipe having a filling chamber liquid-tightly partitioned by a partition wall in an end portion of one first steel pipe;
Providing an outer steel pipe having an inner diameter larger than that of the inner steel pipe at the end of the other second steel pipe;
Inserting the inner steel pipe coaxially into the outer steel pipe;
Injecting an expandable filler into the filling chamber, expanding the inner steel pipe, and frictionally joining the inner steel pipe and the outer steel pipe;
A steel pipe joining method characterized by comprising:

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