JP2019210714A - Concrete filled steel tube pole - Google Patents

Abstract

To provide a concrete filled steel tube pole which improves proof stress and deformability.SOLUTION: Of a concrete filled steel tube pole 1 which includes a steel tube 3 and concrete 5 filled in the steel tube 3, a steel plate 21 is provided on the inner wall 4s of the steel pipe 3 and rises in the direction orthogonal to the inner wall 4s, and on the steel plate 21 a through hole 23 penetrating in the plate thickness direction is formed, and when the width of the steel tube 3 in the direction orthogonal to the inner wall 4s is D, the distance from the part closest to the inner wall of the through hole 23 to the inner wall 4s is equal to or more than D/10.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a concrete-filled steel pipe column.

  Conventionally, a concrete-filled steel pipe column described in Patent Document 1 below is known. In this document, it is proposed that ribs are attached to the inner wall of a steel pipe of a concrete-filled steel pipe column to increase the binding force of the steel pipe by concrete and to increase the proof stress and deformation performance of the concrete-filled steel pipe column.

JP 2012-255248 A

  However, in this type of concrete-filled steel pipe column, further improvement in yield strength and deformation performance is required. In view of this problem, an object of the present invention is to provide a concrete-filled steel pipe column that improves proof stress and deformation performance.

  The concrete-filled steel pipe column of the present invention is a concrete-filled steel pipe column comprising a steel pipe and concrete filled in the steel pipe, and the inner wall of the steel pipe is provided with a steel plate that rises in a direction perpendicular to the inner wall, In the steel plate, a through-hole penetrating in the thickness direction is formed, and when the width of the steel pipe in the direction orthogonal to the inner wall is D, the distance from the portion of the through-hole closest to the inner wall to the inner wall is D / 10 or more It is.

  In the concrete-filled steel pipe column of the present invention, a steel plate is provided on the inner wall of the steel pipe, and a through-hole penetrating in the thickness direction is formed in the steel plate. According to this configuration, since the concrete filled in the steel pipe also enters the through hole of the steel plate, the through hole is strongly held by the concrete. Therefore, the high restraint force of the steel pipe by concrete is obtained through a steel plate. As a result, the yield strength and deformation performance of the concrete-filled steel pipe column are improved.

  Here, let D be the width of the steel pipe in the direction orthogonal to the inner wall. According to various experiments by the present inventors, when out-of-plane buckling of this kind of concrete-filled steel pipe column occurs, there is a possibility of cracking due to concrete crushing in a region from the inner wall to a distance D / 10. Turned out to be expensive. In contrast, in the concrete-filled steel pipe column of the present invention, the distance from the portion closest to the inner wall to the inner wall among the through holes of the steel plate is D / 10 or more. With this configuration, even after cracking of the concrete as described above, there is a high possibility that the entire through-hole is located in a relatively healthy concrete portion inside the cracked region, and the through-hole is retained in that portion. Is likely to be. Therefore, immediately after the occurrence of out-of-plane buckling of the concrete-filled steel pipe column, the function of the through hole is not lost, and there is a high possibility that the steel pipe is restrained by a relatively healthy concrete portion via the steel plate. As a result, the high restraint force of the steel pipe by the concrete is maintained even after the concrete is cracked.

  The plurality of through holes may be provided in the steel plate arranged in the vertical direction, and the cross-sectional area of at least one through hole may be different from the cross-sectional areas of the other through holes. According to this configuration, the cross-sectional area of the through hole can be adjusted according to the required restraining force for each vertical position of the through hole.

  ADVANTAGE OF THE INVENTION According to this invention, the concrete filling steel pipe column which improves a yield strength and a deformation | transformation performance can be provided.

(A) is sectional drawing which shows the concrete filling steel pipe column of 1st Embodiment, (b) is the Ib-Ib sectional drawing. (A) is sectional drawing which shows the crack area | region of the concrete in the lower end part of a column main-body part, (b) is the IIb-IIb sectional drawing. It is sectional drawing which shows the concrete filling steel pipe column of 2nd Embodiment. (A)-(c) is sectional drawing of the lower end part of the concrete filling steel pipe column which concerns on a modification.

  Hereinafter, embodiments of a concrete-filled steel pipe column according to the present invention will be described in detail with reference to the drawings. In the following, as shown in the figure, the vertical direction may be the Z direction, the X direction and the Y direction orthogonal to the horizontal direction may be taken, and X, Y, and Z may be used to describe the positional relationship of each part.

(First embodiment)
Fig.1 (a) is sectional drawing of the concrete filling steel pipe column 1 which concerns on this embodiment, FIG.1 (b) is the Ib-Ib sectional drawing. The concrete-filled steel pipe pillar 1 is used as a pillar of a high-rise building, for example. As shown in FIG. 1, the concrete-filled steel pipe column 1 is a column having a rectangular cross section, and forms a square column having a pair of outer surfaces parallel to the YZ plane and a pair of outer surfaces parallel to the ZX plane. . The concrete-filled steel pipe column 1 includes a square steel pipe 3 extending in the vertical direction (Z direction), and concrete 5 filled in a hollow portion in the steel pipe 3. The steel pipe 3 may be, for example, a welded assembly box-shaped cross-section column or a cold-formed square column. The concrete 5 is formed by being placed in a hollow portion of the steel pipe 3 and cured.

  At the height of each floor of the building, a beam 11 extending in the X direction and a beam 11 extending in the Y direction are connected to the side surface of the concrete-filled steel pipe column 1. Below, the part to which the beam 11 is connected among the concrete filling steel pipe columns 1 is called the connection part 13, and the part between the connection parts 13 is called the column main-body part 15. FIG. Each connecting portion 13 is provided with an inner diaphragm type diaphragm 17 in the steel pipe 3. The diaphragm 17 is located at the same height as the upper and lower flanges 11 a of the beam 11. In plan view, a circular hole is formed in the center of the diaphragm 17.

  Next, the configuration of the upper and lower end portions of the column main body portion 15 will be described. Since the column main body portion 15 has a vertically symmetrical structure, only the configuration of the lower end portion of the column main body portion 15 will be described below, and for the upper end portion, the same or equivalent components are denoted by the same reference numerals and overlapped. Is omitted.

  At the lower end of the column main body 15, one steel plate 21 is provided on each of the four inner walls 4 of the steel pipe 3. Each steel plate 21 is attached to the inner wall 4 by welding, for example, and is attached so as to rise in a direction orthogonal to the inner wall 4. The steel plate 21 is located at the center of the inner wall 4 in the horizontal width direction. Hereinafter, a pair of inner walls parallel to the YZ plane among the inner walls 4 will be referred to as “inner walls 4s”, and a pair of inner walls parallel to the ZX plane will be referred to as “inner walls 4t”. In addition, a pair of steel plates provided on the inner wall 4s among the steel plates 21 is referred to as “steel plate 21s”, and a pair of steel plates provided on the inner wall 4t is referred to as “steel plate 21t”.

  The pair of steel plates 21s rises in a direction opposite to each other toward the column core vertically from each inner wall 4s. The steel plate 21s has a rectangular flat plate shape extending in parallel with the ZX plane, with the horizontal direction (Y direction) parallel to the inner wall 4s being the plate thickness direction. In the X direction, one end of the steel plate 21s is fixed to the inner wall 4s as described above, and the other end of the steel plate 21s is a free end. The steel plate 21 s may be installed with a slight gap immediately above the diaphragm 17 at the top of the connecting portion 13. Alternatively, the lower end of the steel plate 21s may be in contact with the diaphragm 17, and the lower end of the steel plate 21s may be joined to the diaphragm 17 by welding or the like. In addition, from the viewpoint of improving workability, it is preferable that the steel plate 21s and the diaphragm 17 are not joined.

  When the width of the column main body portion 15 in the X direction is Ds, it is preferable that the upper end of the steel plate 21s is positioned above the height position of Ds / 2 from the lower end of the column main body portion 15. Moreover, it is preferable that the width | variety of the X direction of the steel plate 21s is Ds / 5-Ds / 3.

  A through hole 23 is formed in the steel plate 21s so as to penetrate in the thickness direction (Y direction). A plurality of through holes 23 are arranged in the vertical direction (Z direction) with respect to one steel plate 21s. In the example shown in FIG. 1, five through holes 23 having a circular shape with the same diameter are formed in one steel plate 21s. The through-hole 23 is arranged at a certain deep position (position close to the column core) in the concrete-filled steel pipe column 1. Specifically, the distance L from the edge closest to the inner wall 4s to the inner wall 4s among the edges of the through hole 23 is Ds / 10 or more. That is, the entire through-hole 23 exists in a region separated from the inner wall 4s by Ds / 10 or more.

  The steel plate 21t provided on the inner wall 4t parallel to the ZX plane may also have the same configuration as the above steel plate 21s. In this case, when the width of the column main body portion 15 in the Y direction is Dt, with respect to the through hole 23 formed in the steel plate 21t, the edge portion of the through hole 23 that is closest to the inner wall 4t to the inner wall 4t. The distance of is Dt / 10 or more. That is, the entire through-hole 23 exists in a region separated from the inner wall 4t by Dt / 10 or more.

  Then, the effect by the above-mentioned concrete filling steel pipe pillar 1 is demonstrated, referring FIG. In the concrete-filled steel pipe column 1, a steel plate 21s is erected on the inner wall 4s of the steel plate 21s, and a through hole 23 penetrating in the thickness direction is formed in the steel plate 21s. According to this configuration, the concrete 5 filled in the steel pipe 3 also enters the through hole 23 of the steel plate 21s, so that the through hole 23 is strongly held by the concrete. Therefore, the high restraint force of the steel pipe 3 by the concrete 5 through the steel plate 21s is obtained. As a result, the yield strength and deformation performance of the concrete-filled steel pipe column 1 are improved.

  Here, according to various experiments by the present inventors, when the concrete-filled steel pipe column 1 buckles out of plane, as shown in FIG. 2, the region A from both inner walls 4s to a distance Ds / 10 is obtained. Thus, it was found that there was a high possibility that cracking due to the crushing of the concrete 5 would occur. In contrast, in the concrete-filled steel pipe column 1, as described above, the distance L from the portion closest to the inner wall 4s in the through hole 23 of the steel plate 21s to the inner wall 4s is Ds / 10 or more. According to this configuration, even after cracking of the concrete 5 as described above, there is a high possibility that the entire through hole 23 is located in a relatively healthy portion of the concrete 5 inside the cracked area A. There is a high possibility that the through hole 23 is held in the portion. Therefore, immediately after the occurrence of out-of-plane buckling of the concrete-filled steel pipe column 1, the function of the through-hole 23 is not lost, and the steel pipe 3 may be restrained by a relatively healthy portion of the concrete 5 via the steel plate 21s. Is expensive. As a result, the high restraining force of the steel pipe 3 by the concrete 5 is maintained even after the concrete 5 is cracked.

(Second Embodiment)
Then, 2nd Embodiment of the concrete filling steel pipe column of this invention is described, referring FIG. In the concrete-filled steel pipe column 201 of the present embodiment, the same or equivalent components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  It is not essential that all the through holes 23 on one steel plate 21s are the same as in the first embodiment, and the through holes 23 having different cross-sectional areas may be included. As an example, as shown in FIG. 3, consider a case where a buckling wave J as shown by a two-dot chain line in the drawing is assumed due to out-of-plane buckling of the concrete-filled steel pipe column 201 of the present embodiment. In this case, among the five through holes 23 formed in one steel plate 21s, it is preferable that the through hole 23 at a higher position of the buckling wave J is restrained by the concrete 5 with a larger force. Therefore, the through-hole 23 has a larger cross-sectional area and can bear a greater restraining force as the height of the buckling wave J (the length in the X direction) at the place where the through-hole 23 is disposed increases. .

  As a specific example, in the form of FIG. 3, there is a peak of the buckling wave J at the height position of the central through hole 23 c among the five through holes 23. Accordingly, the central through hole 23c is formed in the largest cross section. That is, the through-holes 23a at both upper and lower ends are circular, whereas the central through-hole 23c has a horizontally long elliptical shape with the same vertical width as the through-hole 23a. Further, the through hole 23b located between the through hole 23a and the through hole 23c has an elliptical shape with an intermediate length between the through hole 23a and the through hole 23c. Thus, the cross-sectional area of each through-hole 23 is made to correspond based on the assumed height of the buckling wave J, and the cross-sectional area of the through-hole 23 at that position is increased as the buckling wave J is higher. Such a configuration enables rational design. As another embodiment for changing the cross-sectional areas of the through holes 23a to 23c, the through holes 23a to 23c may be circular holes having different hole diameters.

  In the form of FIG. 3, the length of the assumed buckling wave J (the length in the Z direction) and the vertical width of the steel plate 21s are substantially equal. In such a case, in the vertical direction, the cross-sectional area of the through-hole 23 is formed so as to be closer to the center of the steel plate 21s.

  The present invention can be implemented in various forms including various modifications and improvements based on the knowledge of those skilled in the art including the above-described embodiments. In addition, the following modifications may be configured using the technical matters described in the above-described embodiments. You may use combining the structure of each embodiment suitably.

  For example, in general, the cross section of the concrete-filled steel pipe column 1,201 is square, that is, Ds = Dt, but the cross section of the concrete-filled steel pipe column 1,201 is not limited to a square and may be rectangular. Good. That is, Ds ≠ Dt may be satisfied. Moreover, although the steel plate of embodiment has five through-holes 23 formed in one steel plate 21, the number of through-holes 23 formed in one steel plate 21 can be changed as appropriate. One through hole 23 may be formed in one steel plate 21. Further, the through hole 23 is not limited to a circular shape or an elliptical shape, and may have another shape.

  4 (a) to 4 (c) show cross sections of the concrete-filled steel pipe columns according to the respective modifications at positions crossing the steel plates and the like. As shown in FIG. 4A, one steel plate 51t may be employed instead of the two steel plates 21t, and both ends of the steel plate 51t in the Y direction may be joined to the opposing inner walls 4t and 4t, respectively. . Further, as shown in FIG. 4B, in addition, one steel plate 51s orthogonal to the steel plate 51t is adopted instead of the two steel plates 21s, and both ends of the steel plate 51s in the X direction are opposed to each other. You may join to the inner walls 4s and 4s, respectively. In this case, the steel plate 51t and the steel plate 51s may be integrally formed by welding or the like. The steel pipe 3 having the structure shown in FIG. 4 (a) can be manufactured relatively easily by any method of a welded assembled box-shaped cross-section column and a cold-formed square column. The steel pipe 3 having the structure shown in FIG. 4B is difficult to manufacture as a welded assembly box-shaped cross-section column, and is preferably manufactured by a cold-formed square column system. Further, as shown in FIG. 4C, a plurality of steel plates 21s may be provided for one inner wall 4s. Further, the steel plates 21s need not be arranged on all the four inner walls 4s, 4t.

  Moreover, the diaphragm 17 of the hollow part of the steel pipe 3 is not an indispensable component, and may be a system in which there is no diaphragm in the hollow part of the steel pipe 3, such as an outer diaphragm system or a non-diaphragm system. In this case, the steel plate 21 may be installed so as to extend from the upper end portion of the column main body portion 15 to the lower end portion of the column main body portion 15 on the upper floor over the region including the connection portion 13. Moreover, in the case of the system which does not have a diaphragm in the hollow part of the steel pipe 3, you may install the steel plate 21 so that it may extend over Z direction full length.

  DESCRIPTION OF SYMBOLS 1 ... Concrete filling steel pipe pillar, 3 ... Steel pipe, 5 ... Concrete, 4, 4s, 4t ... Inner wall, 21, 21s, 21t ... Steel plate, 23, 23a, 23b, 23c ... Through-hole.

Claims (2)

A concrete-filled steel pipe column comprising a steel pipe and concrete filled in the steel pipe,
The inner wall of the steel pipe is provided with a steel plate that rises in a direction perpendicular to the inner wall,
In the steel plate, a through-hole penetrating in the thickness direction is formed,
When the width of the steel pipe in the direction orthogonal to the inner wall is D,
A concrete-filled steel pipe column in which a distance from a portion of the through hole closest to the inner wall to the inner wall is D / 10 or more. A plurality of the through holes are arranged in the vertical direction and provided in the steel plate,
The concrete-filled steel pipe column according to claim 1, wherein a cross-sectional area of at least one of the through holes is different from a cross-sectional area of the other through holes.

Images