JP5428867B2 - Steel pipe and steel pipe concrete - Google Patents

Description

  The present invention relates to a steel pipe and steel pipe concrete.

  Some steel pipes used for structures are provided with a fireproof coating in preparation for the occurrence of a fire. Examples of such a fireproof coating include rock wool that is sprayed onto a surface of a steel pipe or the like with a certain thickness (see, for example, Patent Document 1).

JP-A-11-117423

  In the fireproof coating as described above, the thickness of the fireproof coating material is defined in accordance with the fireproof time. For this reason, in order to lengthen a fireproof time, the thickness of a fireproof coating material will become thick and an effective space will be narrowed. In addition, when the fireproof coating is made thin, there is a problem that the fireproof time is shortened, the fireproof performance is low, and it is weak against scratches.

  This invention is made | formed in view of this subject, The place made into the objective is to provide the steel pipe provided with higher fireproof performance, restraining a dimension small, and steel pipe concrete.

  In order to achieve such an object, the steel pipe of the present invention has a steel pipe main body disposed on the inner peripheral side, and a metal plate overlapping portion provided on the outer peripheral side of the steel pipe main body and wound with a metal plate. The metal plate overlapping portion has an outer peripheral portion fixed in a state in which the gap on the inner peripheral side of the metal plate can be expanded and the gap is contracted and wound around the steel pipe body. The fixing is released at a temperature lower than the transformation temperature of the steel pipe body.

  According to such a steel pipe, since the metal plate wound around the outer peripheral side of the steel pipe body is released at a temperature lower than the transformation temperature of the steel pipe body, for example, when the steel pipe is exposed to a flame or the like. The metal plate overlapping part is released before reaching the transformation temperature of the steel pipe body. When the fixing of the metal plate overlapping portion is released, the gap on the inner peripheral side of the metal plate is expanded, so that the fire resistance of the steel pipe can be ensured by the air layer formed on the outer peripheral side of the steel pipe main body.

  Moreover, since the outer peripheral part is fixed in a state where the metal plate overlapping portion is wound around the steel pipe body by shrinking the gap on the inner peripheral side of the metal plate, the state where the gap is expanded in the fixed state The outer diameter is smaller. For this reason, it is possible to provide a steel pipe with higher fire resistance while keeping the dimensions small.

In such a steel pipe, it is desirable that an end portion on the inner peripheral side of the metal plate forming the metal plate overlapping portion is welded to the steel pipe main body.
According to such a steel pipe, the end on the inner peripheral side of the metal plate forming the metal plate overlapping portion is welded to the steel pipe main body, so that even if the fixing on the outer peripheral side of the metal plate overlapping portion is released, the metal plate The plate overlap does not separate from the steel pipe body. For this reason, it is possible to form an air layer reliably on the outer periphery of the steel pipe body.

In this steel pipe, the metal plate is a steel plate, and the steel pipe main body is formed integrally with the metal plate overlapping portion by winding the steel plate, and the steel pipe main body and the metal plate overlapping portion It is desirable that the inner peripheral portion of the boundary portion is welded at the boundary portion.
According to such a steel pipe, the steel pipe main body and the metal plate overlapping portion formed by winding the steel plates are integrally formed, and at the boundary portion between the steel pipe main body and the metal plate overlapping portion, the boundary portion Since the part on the inner peripheral side is welded, a steel pipe main body with high proof stress is formed on the inner peripheral side from the boundary part, and the metal plate overlapping part where the metal plate is wound around the outer periphery of the steel pipe main body is easy Can be formed.

In this steel pipe, it is preferable that the metal plate is plastically deformed with a smaller curvature than the outer peripheral surface of the steel pipe body and is wound around the steel pipe body.
According to such a steel pipe, since it is plastically deformed and wound around the steel pipe body, the metal plate is restored to a plastically deformed state when the outer peripheral portion of the metal plate overlapping portion is released. At this time, since the metal plate is plastically deformed with a smaller curvature than the outer peripheral surface of the steel pipe main body, when the fixation is released, the metal plate is restored so as to be separated from the steel pipe main body. It is possible to form the air layer more reliably by expanding the gap.

In this steel pipe, the metal plate is formed of two kinds of metals having different coefficients of thermal expansion, and the metal having the higher coefficient of thermal expansion among the two kinds of metals has a coefficient of thermal expansion. It is desirable to arrange on the inner circumference side of the lower metal.
According to such a steel pipe, the metal plate is formed of two kinds of metals having different coefficients of thermal expansion, and the metal having the higher coefficient of thermal expansion among the two kinds of metals has the coefficient of thermal expansion. Is disposed on the inner peripheral side of the lower metal, for example, when the steel pipe is exposed to a flame or the like and heated, the metal having the higher thermal expansion coefficient disposed on the inner peripheral side, It expands more than the metal with the smaller coefficient of thermal expansion. For this reason, when the fixing of the outer peripheral portion is released, the metal plate curves in the direction away from the outer peripheral side, i.e., the steel pipe body, so that an air layer can be more reliably formed on the inner peripheral side of the metal plate. Is possible.

In this steel pipe, it is preferable that the outer peripheral portion of the metal plate overlapping portion is fixed by solder.
According to such a steel pipe, since the solder is melted at a temperature lower than the transformation temperature of the steel pipe main body, the fixing of the metal plate overlapping portion is surely released before the steel pipe main body is transformed. It is possible to form an air layer around.

In such a steel pipe, it is preferable that the outer peripheral portion of the metal plate overlapping portion is fixed by an epoxy adhesive.
According to such a steel pipe, since the epoxy adhesive is melted and carbonized at a temperature lower than the transformation temperature of the steel pipe body, the fixing of the metal plate overlapping portion is surely released before the steel pipe body is transformed. Thus, it is possible to form an air layer around the steel pipe body.

The steel pipe concrete is characterized in that the inside of the steel pipe is filled with concrete.
According to such a steel pipe concrete, it is possible to provide steel pipe concrete having higher fire resistance performance while suppressing an increase in size due to the fireproof coating portion by filling the steel pipe with concrete.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the steel pipe provided with higher fireproof performance, and steel pipe concrete, suppressing a dimension small.

It is a perspective view which shows the steel pipe concerning 1st Embodiment. It is a figure for demonstrating the metal plate superposition | polymerization part provided in the steel pipe concerning 1st Embodiment. It is a perspective view which shows the steel pipe concerning 2nd Embodiment.

Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing a steel pipe according to the first embodiment.
As shown in FIG. 1, the steel pipe 10 of 1st Embodiment is arrange | positioned at the inner peripheral side, the steel pipe main body 20 used as the core of the steel pipe 10, the outer peripheral side of the steel pipe main body 20, and the steel plate 31 as a metal plate. And a steel plate overlapping portion 30 as a metal plate overlapping portion.

  As the steel pipe body 20, for example, a steel pipe having a length L of 3000 mm, an outer diameter D of 200 mm, and a wall thickness m of 6 mm is used. The steel pipe main body 20 is appropriately selected depending on the intended use. For example, when the steel pipe 10 is used as a structural material, a steel pipe having a proof strength as a structural material is used as the steel pipe main body even if the steel pipe main body 20 is used alone.

  The steel plate overlapping portion 30 is formed, for example, by winding a long steel plate 31 wound around a roll having a width of 3000 mm and a thickness of 2 mm around the outer periphery of the steel pipe body 20. The steel plate 31 is cut into a predetermined length and wound. Here, for example, when a cold-rolled steel sheet having a thickness of 1.6 to 3.2 mm, which is used for automobiles, is used as the steel sheet, the cost can be reduced.

Drawing 2 is a figure for explaining the steel plate superposition part provided in the steel pipe concerning a 1st embodiment.
The steel plate overlapping portion 30 is plastically deformed with a curvature smaller than the curvature of the outer peripheral surface of the steel pipe main body 20 and is wound around the outer periphery of the steel pipe main body 20. Of the both end portions 31a and 31b in the winding direction of the steel plate 31 forming the steel plate overlapping portion 30, the end portion 31a located on the inner peripheral side is, for example, an arc along the length direction of the steel pipe main body 20 on the outer peripheral surface of the steel pipe main body 20 Welded. Of both end portions 31a and 31b in the winding direction of the steel plate 31 forming the steel plate overlapping portion 30, the end portion 31b located on the outer peripheral side is fixed to the peripheral surface of the steel plate 31 around which the end portion 31b is wound. The fixing of the end portion 31b on the outer peripheral side of the steel plate 31 is joined along the longitudinal direction of the steel pipe 10 by, for example, solder 33 so as to be released at a temperature lower than the transformation temperature of the steel pipe main body 20.

  Since the steel plate 31 is plastically deformed with a curvature smaller than the curvature of the outer peripheral surface of the steel pipe main body 20, as long as the end 31a on the inner peripheral side is simply welded to the steel pipe main body 20, FIG. ), An air layer 25 is formed between the steel pipe body 20 and the steel plate 31 and between the rolled steel plates 31.

  At this time, the thickness of the air layer 25 that is a gap formed on the outer periphery of the steel pipe body 20 is determined by the fire resistance required for the steel pipe 10. That is, when higher fire resistance is required for the steel pipe 10, it is necessary to provide a thick air layer on the outer peripheral side of the steel pipe body 20. For this reason, in order to form a thicker air layer, since the winding number of the steel plate 31 wound around the outer periphery of the steel pipe main body 20 is increased, the length of the steel plate 31 wound up becomes long. Moreover, when high fire resistance is not calculated | required, the winding number of the steel plate 31 wound around the outer periphery of the steel pipe main body 20 can be decreased, and the length of the steel plate 31 wound can be shortened.

  The air layer 25 formed by the steel plate 31 is provided so as to cover at least the outer peripheral surface of the steel pipe main body 20 over the entire circumference in a state where the fixation is released, and desirably, the outer end 31b. The flame that has entered from the side is configured not to reach the steel pipe body 20.

  As shown in FIG. 2A, the steel plate 31 forming the steel plate superposed portion 30 is an end portion on the outer peripheral side as the outer peripheral portion in a state of being wound along the outer periphery of the steel pipe main body 20 so as to shrink the gap. 31 b is fixed with solder 33.

  When the steel pipe 10 of the present embodiment has a fire in a structure used as a pillar, for example, and the steel pipe 10 is exposed to a flame, the outer periphery of the steel plate 31 constituting the steel plate overlapping portion 30 of the steel pipe 10 The solder 33 fixing the side end 31b is melted. The melting temperature of the solder 33 is about 250 ° C., and the transformation temperature of the steel pipe body 20, that is, the temperature at which the yield strength is rapidly lowered by heat is 500 ° C. Therefore, when the solder 33 melts, the steel pipe body 20 reaches the transformation temperature. Not.

  When the solder 33 is melted, as shown in FIG. 2, the steel plate 31 of the steel plate overlapping portion 30 is unfixed and plastically deformed from the state of FIG. 2A wound around the steel pipe body 20. Return to the state of 2 (b). At this time, the steel plate 31 expands in the outer peripheral direction and expands the gap on the inner peripheral side of the steel plate 31. As described above, the spread of the steel plate 31 causes the air layer 25 between the steel plate 31 and the steel pipe body 20 and between the rolled steel plates 31 to spread, thereby suppressing heat transfer to the steel pipe body 20. It demonstrates fireproof performance.

  According to such a steel pipe 10, the steel plate 31 wound around the outer peripheral side of the steel pipe main body 20 is released from being fixed at a temperature lower than the transformation temperature of the steel pipe main body 20. For example, the steel pipe 10 is exposed to a flame. In this case, the steel plate overlapping portion 30 is released before reaching the transformation temperature of the steel pipe body 20. When the fixation of the steel plate overlapping portion 30 is released, the gap on the inner peripheral side of the steel plate 31 is expanded, so that the air layer 25 is formed on the outer peripheral side of the steel pipe main body 20 to ensure the fire resistance performance of the steel pipe 10. Is possible.

  Moreover, since the steel plate superposition | polymerization part 30 shrink | contracts the space | gap of the inner peripheral side of the steel plate 31, and the end part 31b on the outer peripheral side is fixed in order to maintain the state wound around the steel pipe main body 20, in the fixed state, The outer diameter is smaller than that of the expanded gap. For this reason, it is possible to keep the outer dimensions small while providing the steel plate overlapping portion 30 that becomes the fireproof covering portion.

  Moreover, since the end 31a on the inner peripheral side of the steel plate 31 forming the steel plate overlapping portion 30 is arc welded to the steel pipe body 20, even if the fixing by the solder 33 on the outer peripheral side of the steel plate overlapping portion 30 is released, the steel plate Since the overlapping portion 30 is not separated from the steel pipe main body 20, it is possible to reliably form an air layer on the outer periphery of the steel pipe main body 20.

  Further, since the steel plate 31 forming the steel plate superposition part 30 is plastically deformed and wound around the steel pipe body 20, the solder 33 at the end 31b on the outer peripheral side of the steel plate superposition part 30 is melted and the fixation is released. In this case, the steel plate 31 is restored to a plastically deformed state. At this time, since the steel plate 31 is plastically deformed with a smaller curvature than the outer peripheral surface of the steel pipe main body 20, when the fixation is released, the inner circumference of the steel plate 31 is restored by being restored away from the steel pipe main body 20. It is possible to expand the gap on the side more reliably.

  Moreover, since the solder 33 fixing the end 31b on the outer peripheral side of the steel plate superposition part 30 is melted at a temperature lower than the transformation temperature of the steel pipe main body 20, the steel plate superposition part 30 is surely secured before the steel pipe main body 20 is transformed. Can be released. For this reason, it is possible to ensure high fire resistance by forming the air layer 25 on the outer periphery of the steel pipe main body 20 and suppressing heat transfer before the steel pipe main body 20 reaches the transformation temperature.

  In the said 1st Embodiment, although the example which fixed the edge part 31b of the outer peripheral side of the steel plate superposition | polymerization part 30 with the solder 33 was demonstrated, not only this but resin, such as another metal and an epoxy-type adhesive material, Any method may be used as long as the outer peripheral portion of the steel plate overlapping portion 30 is fixed by melting or carbonizing at a temperature lower than the transformation temperature of the steel pipe body 20.

  Moreover, in the said 1st Embodiment, although the metal plate which comprises a metal plate superposition | polymerization part was made into the steel plate, it is not restricted to this. For example, the metal plate may be made of a bimetal formed of two kinds of metals having different coefficients of thermal expansion. In this case, of the two types of metals constituting the bimetal, the metal having the higher coefficient of thermal expansion is arranged on the inner peripheral side than the metal having the lower coefficient of thermal expansion.

  According to such a steel pipe 10, the metal having the larger coefficient of thermal expansion of the bimetallic metal plate is disposed on the inner peripheral side of the metal having the smaller coefficient of thermal expansion. When exposed and heated, the metal having a higher coefficient of thermal expansion disposed on the inner peripheral side expands than the metal having a lower coefficient of thermal expansion. For this reason, when the fixing of the end 31b on the outer peripheral side of the metal plate is released, the metal plate bends in the direction away from the outer peripheral side, that is, the steel pipe main body 20, and thus more reliably on the inner peripheral side of the metal plate. It is possible to form the air layer 25.

  In 1st Embodiment, although the steel plate superposition | polymerization part 30 was demonstrated about the example formed by winding the steel plate 31 in the shape of a spiral, the sheet-like steel plate was made to follow the outer peripheral surface of the steel pipe main body 20, and the steel pipe main body 20 of The steel plate superposed portion 30 is formed of a steel plate having a cylindrical shape provided on the outer peripheral side of the steel pipe main body 20 by being plastically deformed with a smaller curvature than the outer peripheral surface and tightening while being bent and fixing the end portion with solder. May be. At this time, the steel plate formed in a cylindrical shape is formed so that the steel plates have an overlap allowance even when the fixation is released, and a flame or the like does not enter from between the ends of the steel plate. Such a steel pipe adjusts fireproof performance by the number of cylindrical steel plates provided on the outer periphery of the steel pipe main body 20. For example, when the steel pipe is required to have high fire resistance, the number of cylindrical steel plates is increased, and when the steel pipe 10 is not required to have high fire resistance, the number of cylindrical steel plates is decreased. Since such a steel pipe is sequentially heated from the cylindrical steel plate provided on the outer peripheral side due to the temperature rise, the solder is melted and fixed, and the steel plate is restored to a plastically deformed state. It is possible to expand the inner space sequentially.

  Moreover, in 1st Embodiment, although the edge part 31a located in the inner peripheral side in the winding direction of the steel plate 31 which makes the steel plate superposition | polymerization part 30 was demonstrated to the outer peripheral surface of the steel pipe main body 20, the example welded, such as arc welding, The joining of the part 31a and the steel pipe main body 20 may be joining by solder or an epoxy adhesive. In particular, the joint portion between the end portion 31a and the steel pipe body 20 is located inside the steel plate overlapping portion 30 and is less likely to be directly exposed to a flame or the like, so it is considered that the temperature rises due to heat conduction. For this reason, the joining part of the edge part 31a and the steel pipe main body 20 can obtain the high interruption | blocking effect with respect to heat conduction in the direction of joining by solder or an epoxy-type adhesive agent.

  FIG. 3 is a perspective view showing a steel pipe according to the second embodiment. In the following description, the same parts and members as those in the above embodiment are denoted by the same reference numerals and description thereof is omitted.

  Although the steel pipe 10 of 1st Embodiment demonstrated the example which wound and welded the steel plate 31 as a metal plate around the steel pipe main body 20, the steel pipe 12 of 2nd Embodiment also rolled up the steel pipe main body 22 and the steel plate 31, too. The steel plate 31 is formed, and the steel plate 31 constituting the steel pipe main body 22 is extended so that a steel plate superposition portion 35 as a metal superposition portion is formed integrally with the steel pipe main body 22.

  More specifically, as shown in FIG. 3, for example, a long steel plate 31 that is wound in a roll shape, the width direction of the steel plate 31 is the length of the steel pipe 12 so that the outer diameter D is 200 mm. The edge 31c in the width direction of the steel plate 31 is bent into a circular cylindrical shape. For example, when the plate thickness of the steel plate 31 is 2 mm and the thickness m of the steel pipe body 22 is 6 mm, the steel plate 31 is wound three times. At this time, when the steel plate 31 was wound once to become a cylindrical shape, the end portion on the inner peripheral side of the steel plate 31 was arc-welded, and then the steel plate 31 overlapped at an appropriate interval while winding the steel plate 31. Resistance welding the part. When the steel plate 31 is wound three times, the portion where the steel plates 31 overlap is resistance-welded to form the steel pipe body 22. At this time, the steel plates 31 are connected without being cut.

  An end portion of the steel plate 31 forming the steel plate superposition portion 35 by forming the steel plate superposition portion 35 as a metal superposition portion by winding the steel plate 31 that remains integral with the formed steel pipe main body 22 along the outer peripheral surface of the steel pipe main body 22. The steel pipe 12 is formed by fixing 31b to the overlapping part of the steel plate 31 with solder (not shown).

  That is, the steel pipe main body 22 and the steel plate overlapping portion 35 around which the steel plate 31 is wound are integrally formed, and at the boundary portion 36 between the steel pipe main body 22 and the steel plate overlapping portion 35, the boundary portion 36 and the inner peripheral side. The end portion 31b of the steel plate 31 forming the steel plate overlapping portion 35 connected to the steel plate 31 forming the steel pipe body 22 is fixed by soldering.

  At this time, the width of the steel plate 31 serving as the steel plate overlapping portion 35 is processed to be narrower than the portion forming the steel pipe main body 22 so that the steel pipe main body 22 is exposed at the site serving as the end of the steel pipe 12. This is because, when the steel pipe 12 is used as a column, for example, a beam, a slab or the like and the steel pipe main body 22 are joined.

  According to the steel pipe 12 of the second embodiment, the steel pipe body 22 is formed by winding the steel plate 31, and the steel pipe main body 22 and the steel plate overlapping portion 35 as the metal plate overlapping portion are integrally formed. Since the inner peripheral side portion of the boundary portion 36 is resistance-welded at the boundary portion 36 between the steel plate overlap portion 35 and the steel plate overlapping portion 35, the steel pipe main body 22 having high proof stress is formed on the inner peripheral side of the boundary portion 36. In addition, it is possible to easily form the steel plate overlapping portion 35 in which the steel plate 31 is wound around the outer periphery of the steel pipe main body 22.

  It is also possible to use as steel pipe concrete by filling concrete in the steel pipes 10 and 12 of each of the above embodiments.

  The steel plate 31 used in the above embodiment has a high reflectance such as a mirror surface on the outer peripheral side of the steel plate overlapping portions 30 and 35, and the inner peripheral surface is blackened by blowing firewood or the like. It is possible to suppress the temperature rise of the steel pipe main bodies 20 and 22 due to radiation.

  In each of the above embodiments, a cylindrical steel pipe having a circular cross-sectional shape of the steel pipe to be manufactured has been described. However, the cross-sectional shape of the steel pipe is not limited to a circular shape, and may be a rectangular shape or other shapes. .

  Moreover, the said embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof.

10 steel pipes, 12 steel pipes, 20 steel pipe bodies, 22 steel pipe bodies, 25 air layers,
30 steel plate superposition part, 31 steel plate, 31a inner peripheral side end, 31b outer peripheral side end,
31c Edge in width direction, 33 solder, 35 steel plate superposition part,
36 Boundary between steel pipe body and steel plate overlap

Claims (8)

A steel pipe body arranged on the inner peripheral side;
A metal plate overlapping portion provided on the outer peripheral side of the steel pipe body and wound with a metal plate;
The metal plate overlapping portion is capable of expanding the gap on the inner circumference side of the metal plate, the outer circumference is fixed in a state where the gap is contracted and wound around the steel pipe body,
The outer peripheral portion is released from being fixed at a temperature lower than the transformation temperature of the steel pipe body. The steel pipe according to claim 1,
The steel pipe characterized in that an end portion on the inner peripheral side of the metal plate forming the metal plate overlapping portion is welded to the steel pipe main body. The steel pipe according to claim 1 or 2,
The metal plate is a steel plate,
The steel pipe main body is formed integrally with the metal plate overlapping portion by winding the steel plate, and a portion on the inner peripheral side of the boundary portion at a boundary portion between the steel pipe main body and the metal plate overlapping portion. A steel pipe characterized by being welded. A steel pipe according to any one of claims 1 to 3,
The steel pipe is characterized in that the metal plate is plastically deformed with a smaller curvature than the outer peripheral surface of the steel pipe main body and is wound around the steel pipe main body. The steel pipe according to claim 1 or 2,
The metal plate is formed of two types of metals having different coefficients of thermal expansion. Of the two types of metals, the metal having the higher coefficient of thermal expansion is the metal having the lower coefficient of thermal expansion. A steel pipe characterized in that it is arranged on the inner peripheral side. A steel pipe according to any one of claims 1 to 5,
The steel pipe characterized by the outer peripheral part of the said metal plate superimposition part being fixed with the solder. A steel pipe according to any one of claims 1 to 5,
The steel pipe characterized by the outer peripheral part of the said metal plate superimposition part being fixed by the epoxy-type adhesive material.   A steel pipe concrete, wherein the steel pipe according to any one of claims 1 to 7 is filled with concrete.

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