JP2011140764A - Steel pile and steel pipe concrete - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel pipe etc. equipped with higher fire-resistive performance while keeping dimensions small. <P>SOLUTION: This steel pipe body includes a steel pipe body which is arranged on an inner peripheral side, and a plurality of metal plates which cover an outer peripheral surface of the steel pipe body. In the plurality of metal plates, two kinds of metals different in coefficient of thermal expansion from each other are provided on mutually different sides of front and back sides, respectively; the one side in a predetermined direction is fixed to the outer peripheral surface; the other side overlaps another adjacent metal plate, and covers the outer peripheral surface; the metal plate is bent at a temperature lower than a transformation temperature of the steel pipe body, so as to expand a void between the steel pipe body and the metal plate. <P>COPYRIGHT: (C)2011,JPO&INPIT

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 set 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 this object, a steel pipe of the present invention has a steel pipe main body arranged on the inner peripheral side, and a plurality of metal plates covering the outer peripheral surface of the steel pipe main body. Two types of metals having different expansion coefficients are provided on different sides of the front and back surfaces, one side in a predetermined direction is fixed to the outer peripheral surface, and the other side overlaps with another adjacent metal plate to form the outer peripheral surface. The metal plate is a steel pipe that is bent at a temperature lower than a transformation temperature of the steel pipe body to expand a gap between the steel pipe body and the metal plate.

  According to such a steel pipe, the plurality of metal plates covering the outer peripheral surface of the steel pipe main body bend at a temperature lower than the transformation temperature of the steel pipe main body, so that the gap between the steel pipe main body and the metal plate is expanded. For example, when the steel pipe is exposed to a flame, the metal plate provided on the outer periphery of the steel pipe body can be separated from the steel pipe body before reaching the transformation temperature of the steel pipe body. For this reason, it is possible to ensure the fire resistance of the steel pipe by blocking the flame or the like at a position away from the steel pipe body.

  In addition, the plurality of metal plates are fixed to the outer peripheral surface on one side in a predetermined direction, and the other side overlaps with another adjacent metal plate to cover the outer peripheral surface, so that before heating, that is, in a normal state, The outer diameter is smaller than that of the expanded gap. 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, the predetermined direction is a vertical direction, and the plurality of metal plates are fixed to the outer peripheral surface at the lower end side in the vertical direction, and among the two types of metals having different thermal expansion coefficients, It is desirable that the metal having the larger expansion coefficient is provided on the steel pipe main body side.
According to such a steel pipe, since the metal having the larger thermal expansion coefficient is provided on the steel pipe body side, for example, when the steel pipe is exposed to a flame, the metal plate is reached before reaching the transformation temperature of the steel pipe body. Is bent in a direction away from the steel pipe body, and a shielding portion is formed at a position away from the outer peripheral surface of the steel pipe body. For this reason, it is possible to protect a steel pipe main body from a flame and heat. In particular, the steel pipe main body is provided along the vertical direction, and the lower end side of the metal plate is fixed. Therefore, it is possible to effectively block the flame from below by the bent metal plate.

In the steel pipe, the predetermined direction is a circumferential direction of the steel pipe body, and the plurality of metal plates are fixed to the outer peripheral surface on one side in the circumferential direction, and the two types of thermal expansion coefficients are different from each other. Of the metals, the metal having the higher coefficient of thermal expansion may be provided on the outer peripheral side.
According to such a steel pipe, the metal plate whose one side in the circumferential direction is fixed to the outer peripheral surface of the steel pipe main body has an outer peripheral metal having a larger thermal expansion coefficient among two kinds of metals having different thermal expansion coefficients. Since it is provided on the side, when the steel pipe is heated, the metal plate is bent toward the steel pipe main body, and the gap between the metal plate and the outer peripheral surface of the steel pipe main body is expanded. For this reason, since an air layer is formed in the outer periphery of a steel pipe main body, it is possible to prevent the proof stress fall by the heat of a steel pipe main body.

In this steel pipe, the metal plate is heated and swells to the outer peripheral side, and the other end in the circumferential direction is drawn to one side while being in contact with an adjacent metal plate, and the outer peripheral surface of the steel pipe main body is It is desirable to form an air layer in between.
According to such a steel pipe, when the metal plate is heated, the end portion on the other side in the circumferential direction of the metal plate is brought into contact with the adjacent metal plate that is overlapped and drawn toward one side, and the outer peripheral side. As a result of the expansion, an air layer that is substantially closed is formed between the outer peripheral surface of the steel pipe body. At this time, since the plurality of metal plates overlap with other metal plates adjacent on the other side in the predetermined direction, an air layer formed by each metal plate is formed continuously in the circumferential direction of the steel pipe body. For this reason, since the steel pipe body is surrounded by the air layer, it is possible to more reliably prevent a decrease in yield strength due to heat of the steel pipe body.

In such a steel pipe, it is preferable that one of the two types of metals is formed so that one metal is larger than the other metal, and the one metal covers an outer peripheral portion of the steel pipe body.
According to such a steel pipe, since one metal is formed larger than the other metal, and the larger metal covers the outer peripheral part of the steel pipe main body, the outer peripheral part of the steel pipe main body is covered with one metal. It is possible to secure the performance of bending the metal plate with the other small metal while securing the part. For this reason, by reducing the amount of metal used while providing fire resistance, it is possible to reduce the weight of the steel pipe and reduce the cost.

In such a steel pipe, the metal plate is preferably a bimetal.
According to such a steel pipe, since the metal plate is bimetallic, it has two kinds of metals having different coefficients of thermal expansion. Therefore, it is possible to provide a steel pipe having fire resistance simply by fixing to the outer peripheral surface of the steel pipe body. It is possible.

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 provided in the steel pipe concerning 1st Embodiment. It is a figure explaining the deformation | transformation state of the metal plate by heat. It is a perspective view which shows the steel pipe concerning 2nd Embodiment. It is a figure for demonstrating the metal plate provided in 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. FIG. 2 is a view for explaining a metal plate provided in the 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, and the some metal plate 22 provided in the outer peripheral side of the steel pipe main body 20; have. The steel pipe 10 in the first embodiment is used with the length direction arranged along the vertical direction.

  The steel pipe 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 strength as a structural material is used as the steel pipe body 20 even if the steel pipe body 20 is a single body. .

  As shown in FIG. 2, the metal plate 22 is provided with two kinds of metals 23 and 24 having different coefficients of thermal expansion on different sides of the front and back surfaces. The metal plate 22 is a sufficiently small member both in the length direction of the steel pipe body 20 and in the circumferential direction. As for each metal plate 22, the lower end side as one side in the vertical direction as a predetermined direction is welded to the outer peripheral surface 20a of the steel pipe main body 20, and the upper end side as the other side overlaps with another adjacent metal plate 22, and the outer peripheral surface 20a. Covering. For this reason, the part welded to the steel pipe main body 20, ie, the lower end side, is formed smaller than the overlapping part, ie, the upper end side, and the adjacent metal plates 22 overlap to cover the outer peripheral surface 20a of the steel pipe main body 20. It is configured as follows. In FIG. 1, the metal plate 22 is shown as being provided on a part of the steel pipe main body 20, but the metal plate 22 covers the entire peripheral surface of the steel pipe main body 20.

  The metal plate 22 in the present embodiment is such that the metal 23 having a larger coefficient of thermal expansion is smaller than the dimension of the metal 24 having a smaller coefficient of thermal expansion, and the inner peripheral side of the metal 24 having a smaller coefficient of thermal expansion. That is, it is provided on the steel pipe main body 20 side. Both of the two types of metals constituting the metal plate 22 are configured to be deformed at a temperature lower than the transformation temperature of the steel pipe body 20, that is, the temperature at which the proof stress is rapidly reduced by heat. For example, the transformation temperature of the steel pipe body 20 made of steel is about 500 ° C., and the temperature at which the metal plate 22 is deformed is set to 350 ° C.

FIG. 3 is a diagram for explaining a deformed state of the metal plate due to heat.
For example, when the steel pipe 10 of this embodiment is used for a pillar of a building and exposed to a flame by a fire or the like, the metal plate 22 provided on the outer peripheral surface 20a of the steel pipe main body 20 is heated to 350 ° C. Then, the two types of metals 23 and 24 constituting the metal plate 22 start to expand. At this time, as shown in FIG. 3A, the metal 23 having the smaller dimension of the two types of metals 23 and 24 has a larger coefficient of thermal expansion, and therefore the metal plate 22 has the larger dimension. Curved to the metal side. In the case of the first embodiment, since the metal 24 having a smaller coefficient of thermal expansion and a larger size is provided on the outer peripheral side, the metal plate 22 is curved in a direction away from the steel pipe body 20. Then, when each metal plate 22 is curved, each metal plate 22 is in a state where the metal plates 22 spread upward are overlapped as shown in FIG. Is suppressed.

Here, as shown in FIG. 3B, when the metal plate 22 is heated even if the metal 23 having the larger coefficient of thermal expansion is larger than the metal 24 having the smaller coefficient of thermal expansion. In other words, the metal plate 22 bends toward the metal 24 having the smaller coefficient of thermal expansion.

  According to the steel pipe 10 of the first embodiment, the plurality of metal plates 22 covering the outer peripheral surface 20a of the steel pipe body 20 are bent at a temperature lower than the transformation temperature of the steel pipe body 20, and the steel pipe body 20 and the metal plate 22 are For example, when the steel pipe 10 is exposed to a flame, the metal plate 22 provided on the outer periphery of the steel pipe body 20 is separated from the steel pipe body 20 before the transformation temperature of the steel pipe body 20 is reached. It is possible. For this reason, it is possible to ensure the fire resistance performance of the steel pipe 10 by the metal plate 22 blocking the flame or the like at a position away from the steel pipe main body 20.

  The plurality of metal plates 22 are fixed to the outer peripheral surface 20a at the upper end side in a predetermined direction, and the upper end side overlaps with the other adjacent metal plate 22 to cover the outer peripheral surface 20a. In this state, the outer diameter is smaller than the state in which the gap is expanded. For this reason, it is possible to provide the steel pipe 10 provided with higher fireproof performance while keeping the dimensions small.

  Further, since the metal 23 having the larger coefficient of thermal expansion is provided on the steel pipe body 20 side, for example, when the steel pipe 10 is exposed to a flame, the metal plate 22 is formed before reaching the transformation temperature of the steel pipe body 20. A part that is bent in a direction away from the steel pipe body 20 and shielded at a position away from the outer peripheral surface 20a of the steel pipe body 20 is formed. For this reason, it is possible to protect the steel pipe main body 20 from a flame and heat. In particular, the steel pipe main body 20 is provided along the vertical direction, and the lower end side of the metal plate 22 is welded. Therefore, it is possible to effectively block a flame from below by the bent metal plate 22. .

  The metal 23 on the inner peripheral side of the two kinds of metals 23 and 24 constituting the metal plate 22 is formed larger than the metal 24 on the outer peripheral side, and the larger metal 24 forms the outer peripheral surface 20 a of the steel pipe body 20. Since it covers, it is possible to ensure the ability to bend the metal plate 22 with the metal 23 on the inner peripheral side while securing the portion covering the outer peripheral surface 20a of the steel pipe body 20 with the metal 24 on the outer peripheral side. For this reason, it is possible to reduce the amount of the metal 23 used while reducing the cost of the steel pipe 10 while reducing the amount of the metal 23 while having fire resistance.

  FIG. 4 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.

  As for the steel pipe 10 of 1st Embodiment, although the metal plate 22 which is a small piece was turned to the perpendicular direction, and the lower end side was welded to the steel pipe main body 20, the steel pipe 12 of 2nd Embodiment is shown in FIG. A plurality of metal plates 25 having a length substantially the same as the length of the steel pipe main body 20 and having a strip shape with a sufficiently short width relative to the peripheral length of the steel pipe main body 20 are fixed to the outer peripheral surface 20 a of the steel pipe main body 20. .

  The metal plate 25 of the second embodiment is a bimetal composed of two types of metals 26 and 27 having different coefficients of thermal expansion. As shown in FIG. 5, the metal plate 25 has one side in the circumferential direction of the steel pipe main body 20 fixed to the outer circumferential surface 20 a, and the other side in the circumferential direction overlaps with another adjacent metal plate 25 to form the outer circumferential surface 20 a. Covering. The metal plate 25 is provided with a metal 26 having a larger coefficient of thermal expansion on the outer peripheral side of two types of metals having different coefficients of thermal expansion, and a metal 27 having a smaller coefficient of thermal expansion is provided on the steel pipe body 20 side. Is provided.

  When the steel plate 12 is exposed to a flame, the metal plate 25 of the second embodiment constitutes the metal plate 25 when the metal plate 25 provided on the outer peripheral surface 20a of the steel pipe body 20 is heated to 350 ° C. The two types of metals 26 and 27 that start to expand. At this time, as shown in FIG. 5, of the two types of metals 26 and 27, the metal 27 provided on the outer peripheral side has a higher coefficient of thermal expansion, and therefore bends toward the steel pipe body 20 side. Bending is prevented by contacting the main body 20. For this reason, the metal plate 25 is the other end portion in the circumferential direction, and the end portion on the non-fixed side is brought into contact with the adjacent metal plate 25 while being drawn toward the fixed end portion, and the outer periphery. Bulge to the side. At this time, the metal plate 25 is bent so as to expand the gap between the outer peripheral surface 20a of the steel pipe body 20 and the air layer 30 is formed. And the air layer 30 formed of each metal plate 25 covers the outer peripheral surface 20a of the steel pipe main body 20 continuously in the circumferential direction as shown in FIG.

  According to the steel pipe 12 of the second embodiment, the metal plate 25 whose one side in the circumferential direction is welded to the outer peripheral surface 20a of the steel pipe main body 20 is provided with the metal 27 having the larger thermal expansion coefficient on the outer peripheral side. Therefore, when the steel pipe 12 is heated, the metal plate 25 is bent toward the steel pipe main body 20 and the air layer 30 is formed between the metal plate 25 and the steel pipe main body 20. It is possible to prevent the decrease.

  Further, when the metal plate 25 is heated, the end portions of the metal plate 25 that are not fixed in the circumferential direction are brought into contact with the adjacent metal plates 25 that are overlapped and are attracted to the fixed side. By swelling to the side, an air layer 30 that is substantially closed between the outer peripheral surface 20a of the steel pipe body 20 is formed. At this time, since the metal plate 25 is overlapped with the other adjacent metal plates 25 on the fixed side in the circumferential direction, the air layer 30 formed by each metal plate 25 is in the circumferential direction of the steel pipe body 20. It is formed continuously. For this reason, since the steel pipe main body 20 is surrounded by the air layer 30, it is possible to more reliably prevent a decrease in yield strength due to heat of the steel pipe main body 20.

  In addition, since bimetal is used for the metal plate 25, the metal plate 25 has two kinds of metals 26 and 27 having different thermal expansion coefficients in advance, and is simply fire-resistant by being fixed to the outer peripheral surface 20a of the steel pipe body 20. It is possible to easily manufacture the steel pipe 12 provided with.

  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.

  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 pipe, 12 steel pipe, 20 steel pipe main body, 20a outer peripheral surface, 22 metal plate,
23 metal with larger coefficient of thermal expansion, 24 metal with smaller coefficient of thermal expansion,
25 metal plate, 26 metal with smaller thermal expansion coefficient,
27 Metal with higher coefficient of thermal expansion, 30 Air layer

Claims (7)

A steel pipe body arranged on the inner peripheral side;
A plurality of metal plates covering the outer peripheral surface of the steel pipe body,
In the plurality of metal plates, two types of metals having different coefficients of thermal expansion are provided on different sides of the front and back surfaces, one side in a predetermined direction is fixed to the outer peripheral surface, and the other side is adjacent to another metal It overlaps the plate and covers the outer peripheral surface,
The metal plate is bent at a temperature lower than a transformation temperature of the steel pipe body, and expands a gap between the steel pipe body and the metal plate. The steel pipe according to claim 1,
The predetermined direction is a vertical direction,
The plurality of metal plates each have a lower end in the vertical direction fixed to the outer peripheral surface, and a metal having a larger coefficient of thermal expansion among the two types of metals having different coefficients of thermal expansion is provided on the steel pipe body side. A steel pipe characterized by The steel pipe according to claim 1,
The predetermined direction is a circumferential direction of the steel pipe body,
The plurality of metal plates are fixed to the outer peripheral surface at one side in the circumferential direction, and a metal having a larger thermal expansion coefficient is provided on the outer peripheral side among the two types of metals having different thermal expansion coefficients. A steel pipe characterized by The steel pipe according to claim 3,
The metal plate is heated and swells to the outer peripheral side, the other end in the circumferential direction is drawn to one side while being in contact with an adjacent metal plate, and an air layer is formed between the outer peripheral surface of the steel pipe body. Steel pipe characterized by forming. A steel pipe according to any one of claims 1 to 4,
The two types of metals are such that one metal is formed larger than the other metal, and the one metal covers an outer peripheral portion of the steel pipe body. A steel pipe according to any one of claims 1 to 4,
The steel pipe, wherein the metal plate is a bimetal.   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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