JP6545058B2 - Construction method of concrete filled double steel pipe column and concrete filled double steel pipe column - Google Patents

Description

  The present invention relates to a method of constructing a concrete-filled double steel pipe column and a concrete-filled double steel pipe column.

Conventionally, as a method of constructing a concrete-filled steel pipe column, starting of pouring green carbon into the inner steel pipe in a state where the inner steel pipe is lowered from above to the column base portion of the steel pipe column filled with concrete, then to the upper side The outer shell steel pipe was filled with concrete while pulling up the inner steel pipe. For example, in the method of casting a concrete column disclosed in Patent Document 1, an inner steel pipe is disposed in a cylindrical mold, and concrete is filled in the mold through a plurality of openings formed in the inner steel pipe.
In addition, as a method of constructing a concrete-filled double steel pipe column (CFT column), a method of arranging an inner steel pipe in an outer shell steel pipe and filling concrete in the outer shell steel pipe through a plurality of openings formed in the inner steel pipe (See, for example, Patent Document 2). Patent Document 2 proposes an outer shell steel pipe which constitutes a concrete-filled double steel pipe column in which a horizontal stiffening steel (diaphragm) is provided on the inner peripheral surface of an outer shell steel pipe to which a beam member is attached. Also, by providing the horizontal stiffening steel in the outer shell steel pipe, air stagnation is likely to occur, so concrete can not be uniformly filled, and there is a possibility that the quality may become unstable. The steel material is provided with an air vent hole.

Patent No. 5758323 gazette Japanese Patent Laid-Open No. 5-272240

Since the inner steel pipe of the concrete-filled double steel pipe column receives the supply pressure of concrete, there is a possibility that it may become eccentric, and there is a possibility that the strength of the concrete-filled double steel pipe column may be biased if displacement occurs in the placement arrangement.
An object of the present invention is to provide a concrete-filled double steel pipe column excellent in strength and rigidity and a method of constructing the concrete-filled double steel pipe column.

  The first invention for solving the above-mentioned problems is a concrete-filled double steel pipe column including an outer shell steel pipe and an inner steel pipe and filled with concrete, and the inner steel pipe has a plurality of openings high on the outer peripheral surface In the longitudinal direction, they are arranged in a spiral, and on the outer peripheral surface of the inner steel pipe, radial position fixing members are provided at the lower end and the upper end, or at the lower end, the middle portion, and the upper end. It is characterized by being filled up and down with shell steel pipe and inner steel pipe through an opening.

According to the configuration of the first invention, in the concrete-filled double steel pipe column composed of the outer shell steel pipe and the inner steel pipe, the concrete filled in each steel pipe has strength and strength due to the restraint effect by the double steel pipe. Since the rigidity is often increased, a high strength concrete-filled steel pipe column can be realized which exceeds the simple cumulative strength obtained by adding the material strengths of the steel pipe and the concrete.
In addition, by providing a position fixing member for each radial direction at the lower end portion, the upper end portion, or the middle portion of the outer peripheral surface of the inner steel pipe, concrete is densely packed without biasing the inner steel pipe in the outer shell steel pipe. Can realize a double steel pipe column filled with.
In addition, by providing a plurality of openings in a spiral on the outer peripheral surface of the inner steel pipe, a double steel pipe column in which concrete is tightly filled in the outer steel pipe through the openings of the inner steel pipe is realized. be able to.

  In the second invention for solving the above-mentioned problems, the inner steel pipe constituting the concrete-filled double steel pipe column has a continuous spiral uneven rib in which the upper and lower edges of the spirally wound long steel plate are overlapped. It is characterized in that it is a spiral tube.

  According to the configuration of the second aspect of the invention, the inner steel pipe has the convex rib formed on the outer peripheral surface side, and the concave rib is formed in a spiral shape on the inner peripheral surface side corresponding to the convex rib. Since the adhesion strength between the inner steel pipe and the concrete filled inside and outside the inner steel pipe is enhanced, the inner steel pipe and the concrete can be firmly integrated.

In the third invention, the outer shell steel pipe constituting the concrete-filled double steel pipe column, the outer shell steel pipe is provided with a horizontal stiffening steel welded to the inner circumferential surface side, and the horizontal stiffening steel is an air hole It is characterized in that the opening portion provided in the inner steel pipe is disposed at least at a position opposed to the horizontal stiffening steel plate.
According to the configuration of the third invention, the horizontal stiffening steel welded in the outer shell steel pipe has an air hole, and the opening provided in the inner steel pipe is at a high position facing the horizontal stiffening steel plate As a result, it is possible to realize a double steel pipe column densely filled with concrete, without forming an air pool on the upper surface and the lower surface of the horizontal stiffening steel.

  A fourth invention for solving the above-mentioned problems is the method for constructing a concrete-filled double steel pipe column according to the first to third inventions, wherein the outer shell steel pipe is erected on the base and erected The inner steel pipe is inserted and disposed inside the outer shell steel pipe, and a hopper for receiving a concrete is installed above the inner steel pipe, and the outer circumferential surface of the outer shell steel pipe is mounted at the mounting height position of the horizontal stiffening steel plate. Fresh concrete is supplied from the inner steel pipe side while vibration is applied, and the concrete is filled into the outer shell steel pipe through the opening of the inner steel pipe.

According to the configuration of the fourth aspect of the present invention, the inner steel pipe whose opening is provided spirally on the outer peripheral surface is disposed in the outer steel pipe, and the radial position is provided at the lower end, middle and upper end of the inner steel pipe. By providing the fixing member, concrete can be uniformly filled in the outer shell steel pipe through the opening of the inner steel pipe while preventing positional deviation of the inner steel pipe.
In addition, by applying external vibration to the outer peripheral surface of the outer shell steel pipe to which the horizontal stiffening steel is welded, concrete is concentrated in the outer shell steel pipe without forming an air pool on the upper surface or the lower surface of the horizontal stiffening steel. It can be driven. Alternatively, the vibrator may be lowered from above the inner steel pipe to the periphery of the horizontal stiffening steel to apply external vibration directly to fresh concrete.
Alternatively, the concrete-filled double steel pipe column concrete may be supplied from the hopper through the supply hose into the inner steel pipe. In this case, since the distance over which the concrete freely falls can be shortened, separation of the material of the concrete within the inner steel pipe can be prevented.

  According to the present invention, a concrete-filled double steel pipe column excellent in strength and rigidity is obtained by embedding the inner steel pipe in the outer shell steel pipe and placing the inner steel pipe through the inner steel pipe on solid concrete in the outer shell steel pipe. It can be realized.

It is a side sectional view showing a concrete filled double steel pipe column concerning an embodiment of the present invention. It is an axial sectional view showing a concrete-filled double steel pipe column concerning an embodiment of the present invention, (a) is an A-A sectional view of FIG. 1, (b) is a B-B sectional view of FIG. ) Is a cross-sectional view taken along the line C-C in FIG. It is a perspective view showing an inner steel pipe concerning an embodiment of the present invention. It is an expanded view of the inner steel pipe which concerns on embodiment of this invention. In the construction method of the concrete filling double steel pipe column concerning the embodiment of the present invention, it is the sectional side view which showed the stage which fills the concrete in outer shell steel pipe. It is the schematic which showed the concrete filling double steel pipe column for performance confirmation experiment. Measurement results of air bubble in horizontal cut surface of concrete filled double steel pipe column in filling test of concrete, (a) image showing upper end position of horizontal stiffening steel, (b) lower of horizontal stiffening steel It is the image which showed the end surface position.

Embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, the concrete-filled double steel pipe column 1 of the present embodiment temporarily fixes the inner steel pipe 20 at the center of the outer shell steel pipe 10 and strikes the concrete 30 in the outer steel pipe 10 through the inner steel pipe 20. It is a CFT pillar set up and formed.
The concrete-filled double steel pipe column 1 of the present embodiment includes an outer shell steel pipe 10 and an inner steel pipe 20 temporarily fixed in the outer shell steel pipe 10, and the concrete in the outer shell steel pipe 10 and the inner steel pipe 20 is concrete. There are 30 in force.
The first feature of the concrete-filled double steel pipe column 1 of the present embodiment is that, when placing the concrete 3 in the outer shell steel pipe 10, the concrete is inserted outside through the opening 27 spirally provided on the outer peripheral surface of the inner steel pipe 20. Concrete 30 can be radially uniformly filled in the shell steel pipe 10. The second feature is that the concrete 30 constituting the concrete-filled double steel pipe column 1 is made of the steel pipes 10 and 20 and concrete 30 by the restraint effect of the outer steel pipe 10 and the inner steel pipe 20 by the double steel pipe. It is a point which can realize a high-strength concrete-filled steel pipe column 1 exceeding the simple accumulated strength which is the sum of the material strengths.

The outer shell steel pipe 10 is a square cylindrical steel pipe having a square axial cross section (see FIG. 2A). The outer shell steel pipe 10 constitutes the outer peripheral wall of the concrete-filled double steel pipe column 1. The outer shell steel pipe 10 is vertically erected on the base surface 2 such as a ground surface or a floor surface.
At a predetermined height of the outer shell steel pipe 10, a connection portion to which two beam members 40, 40 are connected is provided. A horizontal stiffening steel 50 (diaphragm) for dividing the inside of the outer shell steel pipe 10 into upper and lower portions is provided at a position corresponding to the connection portion inside the outer shell steel pipe 10. In the present embodiment, two horizontal stiffening steels 50, 50 are arranged at an interval in the vertical direction.
As shown in FIG. 2 (b), a circular insertion hole 51 is formed at the center of the horizontal stiffening steel 50. The insertion hole 51 is an opening through which the inner steel pipe 20 is inserted in the vertical direction.
The inner diameter of the insertion hole 51 is formed larger than the outer diameter of the inner steel pipe 20. Therefore, when the concrete 30 is filled in the outer shell steel pipe 10 between the inner peripheral edge of the insertion hole 51 and the outer peripheral surface of the inner steel pipe 20 in a state where the inner steel pipe 20 is inserted into the insertion hole 51 In addition, a space portion (gap) in which the concrete 30 flows is formed. Further, in the horizontal stiffening steel 50, four air holes 52 are formed at the four corners.

The internal steel pipe 20 is a cylindrical steel pipe extending in the vertical direction as shown in FIG. 1 (see FIG. 3). The inner steel pipe 20 is temporarily fixed in the outer shell steel pipe 10 via position fixing rebars 61, 72, 81.
The inner steel pipe 20 is a supply pipe for placing the concrete 30 in the outer steel pipe 10. The inner steel pipe 20 is left behind in the concrete 30 in the outer steel pipe 10 after the concrete 30 is filled in the outer steel pipe 10.
The inner steel pipe 20 is formed by connecting upper and lower two spiral ducts 21 and 22.
As shown in FIG. 3, the spiral ducts 21 and 22 have a peripheral wall formed by spirally winding a long steel plate (strip-like plate). The outer peripheral surface of the spiral ducts 21 and 22 is formed with an uneven rib 24 in which the upper and lower edges of the long steel plates arranged vertically are continuously overlapped.
The upper end portion of the first spiral duct 21 and the lower end portion of the second spiral duct 22 are connected by being fitted to the cylindrical connecting pipe 25. Thus, by using the connecting pipe 25, the upper and lower spiral ducts 21 and 22 can be connected without reducing the diameter, and the inner diameters of both the spiral ducts 21 and 22 can be formed to a certain size. .
Further, the connection pipe 25 is disposed above the horizontal stiffening steel 50 and is used for a connection portion of the first spiral duct 21 and the second spiral duct 22 or a connection portion of the second spiral ducts 22 and 22. Be The inner diameter of the connecting pipe 25 is larger than the outer diameter of both the spiral ducts 21 and 22, and they are connected by screws or clamps so as not to reduce the inner diameter of the spiral ducts 21 and 22.

At the lower end of the outer peripheral surface of the first spiral duct 21, two first openings 26, 26 extending in the vertical direction are formed. The first opening 26 is formed in a rectangular shape in a side view, as shown in FIG. The first opening 26 passes through the peripheral wall of the lower spiral duct 21 (see FIG. 2C).
The ribs 24 in the first opening 26 are not cut, and the ribs 24 are bridged on both side edges of the first opening 26. Thus, by leaving the rib 24 in the first opening 26, the strength of the lower end portion of the first spiral duct 21 can be sufficiently secured.
The two first openings 26, 26 face each other across the central axis of the first spiral duct 21, as shown in FIG. 2 (c).
Although the first opening 26 of the present embodiment is formed above the lower edge of the first spiral duct 21 as shown in FIG. 1, the first opening 26 is not limited to the first. It may be formed to reach the lower edge of the spiral duct 21 of FIG.

Four second openings 27 are formed on the outer peripheral surface of the first spiral duct 21 at positions above the first openings 26 and 26. In addition, one second opening 27 is formed in the outer peripheral surface of the second spiral duct 22. The second opening 27 penetrates the peripheral wall of the spiral ducts 21 and 22 (see FIGS. 2A and 2B).
The plurality of second openings 27 are helically spaced along the spiral direction of the peripheral wall of the spiral ducts 21 and 22 (see FIG. 4). That is, a plurality of second openings 27 are spirally arranged in parallel in the spiral ducts 21 and 22.
The plurality of second openings 27 are spaced apart in the vertical direction, and are alternately arranged on one side and the other side of the outer peripheral surface of the spiral ducts 21 and 22 as shown in FIG. ) (See FIG. 5). That is, of the second openings 27 and 27 arranged vertically, the upper second opening 27 is formed obliquely upward with respect to the lower second opening 27.
The second opening 27 is formed between the upper and lower sides of the rib 24 formed on the outer peripheral surface of the spiral ducts 21 and 22. That is, the upper and lower edges of the second opening 27 are formed by the ribs 24. Thus, the upper and lower edges of the second opening 27 are formed along the slope of the rib 24. Thus, the second opening 27 extends obliquely with respect to the axial direction of the inner steel pipe 20. The first opening 26 and the second opening 27 are rectangular holes or elliptical holes in which the projections (ribs 24) of the spiral ducts 21 and 22 are left.
In the inner steel pipe 20 of the present embodiment, since the ribs 24 of the spiral ducts 21 and 22 are continuous, the first opening 26 and the second opening 27 are formed in the outer peripheral surface of the spiral ducts 21 and 22. Also, the strength of the spiral ducts 21 and 22 can be sufficiently ensured.
The first opening 26 at the lowermost end is formed in a long hole that is larger than the other second openings 27. By setting the first opening 26 to a large diameter, it is possible to form a rooted concrete portion in a short time in the column base portion of the concrete-filled double steel pipe column 1 and fix the position of the inner steel pipe 20 .

  As shown in FIG. 1, in the state where the inner steel pipe 20 is fixed in the outer shell steel pipe 10, the uppermost second opening 27 of the four second openings 27 of the first spiral duct 21 is The upper horizontal stiffening steel 50 is straddled in the vertical direction, and the second second opening 27 from the top is configured to straddle the lower horizontal stiffening steel 50 in the vertical direction (see FIG. 5). . That is, at least one second opening 27 is disposed at a position opposed to the horizontal stiffening steel 50, and opens at the upper side and the lower side of the horizontal stiffening steel 50.

At the lower end portion of the first spiral duct 21, a position fixing reinforcing bar 60 at the lowermost end portion is provided. The position fixing rebar 60 at the lowermost end is a member for arranging the inner steel pipe 20 perpendicularly to the base surface 2. The position fixing rebar 60 at the lowermost end portion is a frame body in which four horizontal rebars 61 are combined in a grid shape, as shown in FIG. 2C, and surrounds the outer peripheral surface of the first spiral duct 21. (See Figure 3).
Each horizontal reinforcing bar 61 of the position fixing rebar 60 at the lowermost end portion is disposed perpendicularly to the axial direction of the first spiral duct 21 (see FIG. 1). Each horizontal reinforcing bar 61 of the position fixing rebar 60 at the lowermost end is joined to the outer peripheral surface of the first spiral duct 21. Further, as shown in FIG. 1, the position fixing rebar 60 at the lowermost end portion is formed in a size that can pass through the insertion hole 51 of the horizontal stiffening steel 50.
Then, the position fixing rebar 60 at the lowermost end is placed on the base surface 2 so that the inner steel pipe 20 is disposed perpendicularly to the base surface 2.
Further, a guide reinforcing bar 62 composed of a ring reinforcing bar surrounding the first spiral duct 21 and four diagonal reinforcing bars is provided above the position fixing reinforcing bar 60 at the lowermost end. The guide rebar 62 is a member for arranging the first spiral duct 21 at the center of the outer shell steel pipe 10.

As shown in FIG. 1, a reinforcing bar 70 for fixing the position of the middle portion is provided at a substantially middle portion in the height direction of the first spiral duct 21. The position fixing rebar 70 at the middle part is a member for determining the position of the inner steel pipe 20 in the vertical direction. The position fixing rebar 70 in the middle part is a frame body in which four horizontal rebars 71 are combined in a grid shape, as shown in FIG. 2 (b), and surrounds the outer peripheral surface of the first spiral duct 21. (See Figure 3).
Each horizontal reinforcing bar 71 of the intermediate position fixing bar 70 is disposed perpendicularly to the axial direction of the first spiral duct 21. Each horizontal reinforcing bar 71 of the intermediate position fixing bar 70 is joined to the outer peripheral surface of the first spiral duct 21.
Then, as shown in FIG. 1, the position fixing rebar 70 of the middle portion is placed on the upper surface of the upper horizontal stiffening steel member 50, whereby the position of the inner steel pipe 20 in the vertical direction is determined.
Further, a guide reinforcing bar 72 including a ring reinforcing bar surrounding the first spiral duct 21 and four diagonal reinforcing bars is provided on the upper portion of the position fixing reinforcing bar 70 in the middle portion. The guide reinforcing bar 72 is a member for arranging the first spiral duct 21 at the center of the outer shell steel pipe 10. Specifically, the lower end side of the guide reinforcing bar 72 is joined to the outer peripheral surface of the upper second spiral duct 22, and the upper end side of the guide reinforcing bar 72 is in contact with the four corners of the inner peripheral surface of the outer shell steel pipe 10 respectively. Preferably, the positions of the spiral ducts 21 and 22 (inner steel pipe 10) are fixed.

At the upper end of the second spiral duct 22, a position fixing rebar 80 at the top end is provided. The position fixing rebar 80 at the top end is a member for positioning the inner steel pipe 20 at the center of the outer shell steel pipe 10. The position fixing rebar 80 at the top end portion is constituted by four diagonal rebars 81 having the same length as shown in FIG. 2A (see FIG. 3).
The inner end of each diagonal rebar 81 of the top end position fixing rebar 80 is joined to the outer peripheral surface of the upper second spiral duct 22, and each of the diagonal rebar 81 of the top end position fixing rebar 80. The outer end portions are respectively brought into contact with the four corners of the inner peripheral surface of the outer shell steel pipe 10 to fix the positions of the spiral ducts 21 and 22 (inner steel pipe 10).
Then, as shown in FIG. 1, each diagonal rebar 81 of the position fixing rebar 80 at the top end is interposed between the outer peripheral surface of the upper spiral duct 22 and the four corners of the inner peripheral surface of the outer shell steel pipe 10. By being provided, the upper spiral duct 22 is fixed in position at the center of the outer shell steel pipe 10. In addition, if both upper ends of the guide rebar 72 in the middle part and the rebar 80 for fixing the position of the uppermost end are brought into contact with the four corners of the inner peripheral surface of the outer shell steel pipe 10 respectively, The positions of the spiral ducts 21 and 22 (inner steel pipe 10) to be arranged can be firmly fixed at different height positions of the middle portion and the top end.

  In the concrete-filled double steel pipe column 1 of the present embodiment, concrete 30 is cast in the outer shell steel pipe 10 using the inner steel pipe 20. That is, the concrete 30 is cast between the outer peripheral surface of the inner steel pipe 20 and the inner peripheral surface of the outer shell steel pipe 10. Further, concrete 30 is also cast in the inner steel pipe 20 (see FIG. 2 (a)). Concrete 30 is cast to a position (for example, 300 mm or more) lower than the upper end edge of outer shell steel pipe 10. In the present embodiment, the concrete 30 is cast to the lower end of the position fixing rebar 80 at the uppermost end. Further, the height of the upper end edge portion of the inner steel pipe 20 is set in accordance with the height of the upper end surface of the concrete 30. That is, the position of the upper end edge of the inner steel pipe 20 is a position lower than the upper end edge of the outer shell steel pipe 10, and has the same height as the lower end of the position fixing rebar 80 at the uppermost end.

Next, a method of constructing the above-described concrete-filled double steel pipe column 1 will be described.
As shown in FIG. 5, the outer shell steel pipe 10 is erected perpendicularly to the base surface 2. Subsequently, the inner steel pipe 20 is inserted into the outer steel pipe 10 from the upper end opening of the outer steel pipe 10.
In the inner steel pipe 20, the position fixing rebar 60 at the lowermost end, the position fixing rebar 70 at the middle portion, and the position fixing rebar 80 at the top end are joined in advance. The position fixing rebar 60 at the lowermost end portion is disposed at a substantially central position of the column base portion in the outer shell steel pipe 10 in a state of being joined to the inner steel pipe 20 in advance.
The lower end portion of the inner steel pipe 20 is brought into contact with the base surface 2, and the entire inner steel pipe 20 is installed in the outer shell steel pipe 10.
When the position fixing rebar 60 at the lowermost end is brought into contact with the base surface 2, the inner steel pipe 20 is disposed perpendicularly to the base surface 2. Further, when the position fixing rebar 70 at the middle portion is brought into contact with the upper surface of the upper horizontal stiffening steel 50, the inner steel pipe 20 is positioned in the vertical direction. Further, when the position fixing rebar 80 at the uppermost end is brought into contact with the four corners of the inner peripheral surface of the outer shell steel pipe 10, the position of the inner steel pipe 20 is fixed substantially at the center of the outer shell steel pipe 10.

After temporarily fixing the inner steel pipe 20 in the outer shell steel pipe 10, the hopper 4 is disposed above the outer shell steel pipe 10. Once fresh concrete (fresh concrete) is introduced into the hopper 4, the concrete 30 is dropped into the internal steel pipe 20 from the outlet 4 a of the hopper 4.
A flexible resin (polyvinyl chloride) supply hose 4b is connected to the outlet 4a of the hopper 4, and the concrete 30 is dropped from the tip of the supply hose 4b into the inner steel pipe 20. Thereby, since the distance which fresh concrete falls can be made small, it can prevent that the material of fresh concrete separates within internal steel pipe 20.

The concrete 30 supplied into the inner steel pipe 20 is radially filled from the first openings 26, 26 of the inner steel pipe 20 in the outer shell steel pipe 10. Furthermore, concrete 30 flows out from the upper second opening 27 into the outer shell steel pipe 10 sequentially, and the concrete 30 is filled in the inner steel pipe 20 and the outer shell steel pipe 10.
When the concrete 30 reaches the upper and lower horizontal stiffening steels 50, 50, the outer circumferential surface of the outer shell steel pipe 10 is externally vibrated by a vibrator such as a vibrator at the mounting height position of both horizontal stiffening steels 50, 50. Thereby, the air in the concrete 30 is moved along the upper surface or the lower surface of the horizontal stiffening steel 50 to the vicinity of the air hole, and is discharged from the air hole.
Then, the inside of the outer shell steel pipe 10 is filled with concrete 30 up to the lower end of the position fixing rebar 80 at the uppermost end, and the concrete 30 is hardened. Thus, a concrete-filled double steel pipe column 1 is constructed.
After concrete 30 is cast in outer shell steel pipe 10, reinforcing bar 80 for fixing the position of the uppermost end is exposed at the upper part of outer shell steel pipe 10, so when joining other inner steel pipes 20, The steel pipe 20 passes through the center of the position fixing rebar 80 at the top end and is disposed at the center of the outer shell steel pipe 10. Thus, it plays the role of a guide member of the rebar 80 internal steel pipe 20 for position fixing of the uppermost end.

In the concrete-filled double steel pipe column 1 as described above, as shown in FIG. 1, the second opening 27 of the inner steel pipe 20 is configured to straddle the horizontal stiffening steel 50 in the vertical direction. In addition, when concrete 30 is filled in the outer shell steel pipe 10, the outer shell steel pipe 10 is externally vibrated at a position corresponding to the horizontal stiffening steel 50.
Then, in the concrete filled double steel pipe column 1, when the outer shell steel pipe 10 is filled with the concrete 30, the air in the concrete 30 is discharged upward through the inner steel pipe 20. As a result, in the concrete-filled double steel pipe column 1, it is possible to suppress the occurrence of air accumulation in the concrete 30 on the upper surface side and the lower surface side of the horizontal stiffening steel 50, so It can be driven.
Further, in the concrete-filled double steel pipe column 1, strength and rigidity are often increased by the restraint effect of the outer steel pipe 10 and the inner steel pipe 20 by the double steel pipe. It is possible to realize a high-strength concrete-filled double steel pipe column 1 exceeding the simple cumulative strength in which the material strengths of the steel pipes 10 and 20 and concrete 30 are added.
Further, in the concrete-filled double steel pipe column 1, the reinforcing bars 60, 70, 80 for fixing the position in the radial direction are provided at the lower end, middle and upper end of the outer peripheral surface of the inner steel pipe 20, respectively. The concrete-filled double steel pipe column 1 in which the concrete 30 is densely filled can be realized without biasing the inner steel pipe 10 in the shell steel pipe 20.

In the concrete-filled double steel pipe column 1, it is not necessary to pull out the inner steel pipe 20 from the inside of the outer shell steel pipe 10, and the filling amount of the concrete 30 can be grasped by the height position of the upper surface of the concrete 30 in the inner steel pipe 20. Therefore, the filling operation of the concrete 30 can be easily managed.
Further, in the concrete-filled double steel pipe column 1, filling the concrete 30 in the inner steel pipe 20 in a state where the inner steel pipe 20 is temporarily fixed in the outer steel pipe 10 by the position fixing rebars 60, 70, 80 Since it can be done, the workability at the time of filling the concrete 30 can be improved.

[Performance confirmation experiment]
Next, for the purpose of confirming the effect of the present invention, a concrete filling test of concrete using internal steel pipes was performed on a reduced concrete-filled double steel pipe column model for the first floor to the third floor of a real building. The test method and the result of filling concrete will be described below.
In the test method, first, as shown in FIG. 6, concrete was filled in the outer shell steel pipe 10 using the inner steel pipe 20 provided with the openings 26 and 27. After the concrete hardens, multiple locations of the concrete-filled double steel pipe column 1 are cut in the horizontal direction, and the horizontal cut surface is subjected to image processing, and the air pool (air bubbles present in the concrete of the concrete-filled double steel pipe column 1 Section) was measured to confirm the filling performance of the concrete.

As shown in FIG. 6, the outer shell steel pipe 10 of the test specimen is provided upright on the upper surface of the level adjustment mortar 3. The outer shell steel pipe 10 is a square tubular steel pipe having a side wall of 418 mm on one side, a thickness of 12 mm on the side wall, and a height of 5990 mm.
In the outer shell steel pipe 10, three horizontal stiffening steels 50A to 50C were installed to simulate a diaphragm provided on a concrete-filled double steel pipe column of a real building. The thickness of each horizontal stiffening steel 50A to 50C is 24 mm. An insertion hole 51 having a diameter of 250 mm is formed at the center of each of the horizontal stiffening steels 50A to 50C.
The lowermost horizontal stiffening steel member 50 </ b> A is disposed at a distance of 3160 mm from the upper surface of the level adjustment mortar 3. The middle stage horizontal stiffening steel 50B is disposed 176 mm above the top surface of the lowermost horizontal stiffening steel 50A. In addition, the uppermost horizontal stiffening steel 50C is disposed 652 mm above the top surface of the middle horizontal stiffening steel 50B.

The inner steel pipe 20 of the experimental test body is obtained by connecting three spiral ducts 21, 22, 23. The inner steel pipe 20 is a cylindrical steel pipe having a diameter of 115 mm and a height of 5690 mm.
At the lower end of the inner steel pipe 20, a first opening 26 having a height of 690 mm and a width of 115 mm is formed. Further, in the inner steel pipe 20, a plurality of second openings 27 are formed spirally at predetermined intervals. The second opening 27 is formed to have a height of 135 mm and a width of 115 mm. In the inner steel pipe 20 of the experimental test body, ten second openings 27 are arranged in a staggered manner at intervals in the vertical direction.
Further, three second openings 27 of the second openings 27 respectively extend over the horizontal stiffening steels 50A to 50C in the vertical direction.

In this experiment, high fluidity concrete with slump flow of 60 cm is filled in the outer shell steel pipe 10 through the inner steel pipe 20. Further, at the mounting height positions of the horizontal stiffening steels 50A to 50C, vibration is applied to the outer peripheral surface of the outer shell steel pipe 10 by a vibration generator such as a vibrator.
Thus, concrete is cast in the outer shell steel pipe 10 and in the inner steel pipe 20. After the concrete hardens, the concrete-filled double steel pipe column 1 is horizontally cut in the vicinity of the lower surface of each of the horizontal stiffening steels 50A to 50C.
Then, the cut surface of the concrete was photographed by a camera, and the image was subjected to image processing by a computer to calculate the filling rate of concrete.
FIG. 7 shows the measurement results of the bubble in the horizontal cut surface of the concrete-filled double steel pipe column 1 sandwiching the middle horizontal stiffening steel 50B in the filling test of concrete using the reduced concrete-filled double steel pipe column model Show.
FIG. 7 (a) shows the upper end surface position of the horizontal stiffening steel 50B, and FIG. 7 (b) shows the lower end surface position of the horizontal stiffening steel 50B. The hatched portion in the figure indicates a bubble portion, and in the double circular outline near the center, the inner circular outline indicates the cut position of the inner steel pipe 20, and the outer circular outline indicates the horizontal stiffening steel 50B. It corresponds to the inside and is the position of the insertion hole.
From the measurement results of FIG. 7 (a) and FIG. 7 (b), the bubble portion is not formed intensively at a specific position, and the bubble portion formed in the column concrete portion sandwiching the horizontal stiffening steel 50B. Is the average value of 1.4% per horizontal cross sectional area of the column. Moreover, the average of the bubble part which pinched | interposed the horizontal stiffening steel 50A of a lower side and the horizontal stiffening steel 50C of an upper side is 1.1% and 0.5%.
According to the test results, in the concrete filling method using the inner steel pipe 20 of the present invention, large air bubble portions are not formed at specific positions on the upper surface and the lower surface of the horizontal stiffening steels 50A to 50B, and the concrete is dense It was possible to confirm that it was actually filled.

[Modification]
As mentioned above, although embodiment of this invention was described, this invention can be suitably changed in the range which does not deviate from the meaning, without being limited to the said embodiment.
In the concrete-filled double steel pipe column 1 of the present embodiment, as shown in FIG. 1, the cylindrical inner steel pipe 20 is disposed in the rectangular cylindrical outer shell steel pipe 10, but in the outer shell steel pipe and the inner steel pipe The shape is not limited.
Further, in the concrete-filled double steel pipe column 1 of the present embodiment, the beam member 40 is joined to a predetermined height of the outer shell steel pipe 10, but the joint member connected to the beam member 40 is used as the outer shell steel pipe 10. You may attach it.
Further, the shape and the number of the second openings 27 are not limited, and are appropriately set in accordance with the filling amount and the flow of the concrete 30.

Reference Signs List 1 concrete filled double steel pipe column 2 base surface 3 level adjustment mortar 4 hopper 4a outlet 4b supply hose 10 outer shell steel pipe 20 inner steel pipe 21 first spiral duct 22 second spiral duct 24 rib 25 connecting pipe 26 first Opening 27 Second opening 30 Concrete 40 Beam member 50 Horizontal stiffening steel 51 Insertion hole 52 Air hole 60 Rebar for fixing the lower end of the inner steel pipe 70 Rebar for fixing the middle part of the inner steel pipe 80 Internal steel pipe Retaining rebar 61, 71 horizontal rebar 81 diagonal rebar at the top end of the frame

Claims (4)

A concrete filled double steel pipe column filled with concrete, comprising an outer shell steel pipe and an inner steel pipe,
In the inner steel pipe, a plurality of openings are arranged in a spiral in the height direction on the outer peripheral surface, and
On the outer peripheral surface of the inner steel pipe, radial position fixing members are provided on the lower end side and the upper end side, or on the lower end side, the middle portion, and the upper end side,
A concrete-filled double steel pipe column, wherein the concrete is filled in the inside and the outside of the outer shell steel pipe and the inner steel pipe through the opening.   The concrete-filled double according to claim 1, wherein the inner steel pipe is a spiral pipe having a continuous spiral uneven rib in which upper and lower edges of a spirally wound long steel plate are overlapped. Steel pipe column. The outer shell steel pipe includes a horizontal stiffening steel welded to the inner circumferential surface side, and the horizontal stiffening steel has an air hole,
The concrete-filled double steel pipe column according to claim 1 or 2, wherein the opening provided in the inner steel pipe is disposed at least at a location facing the horizontal stiffening steel plate. A method of constructing a concrete-filled double steel pipe column according to any one of claims 1 to 3, which is:
Standing the outer shell steel pipe on the base,
Inserting and arranging the inner steel pipe inside the erected outer shell steel pipe,
Install a concrete receiving hopper above the inner steel pipe,
A method of constructing a concrete-filled double steel pipe column, wherein fresh concrete is supplied from the inner steel pipe side, and concrete is filled into the outer shell steel pipe through the opening of the inner steel pipe.