JP2005232749A - Joint structure between steel pipe column and flat slab - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joint structure between a concrete filled steel pipe column and a flat slab for more reliably and sufficiently inhibiting bending moment from being applied to a steel pipe column resulting from the load of the flat slab than conventional while requiring lower cost, so much. <P>SOLUTION: As an upper steel pipe 1 forming a steel pipe column portion at an upper hierarchy of adjacent upper and lower hierarchies of a steel pipe column 10, a steel pipe is adopted which has an outer diameter D1 smaller than an outer diameter D2 of a lower steel pipe 2 forming a steel pipe column portion at a lower hierarchy. In the joint structure A, A', B, or C, the upper and lower steel pipes 1, 2 are connected to each other via an upper steel pipe supporting plate 3 having a concrete through-hole 31, the flat slab 5 is installed on a stepped shelf portion S between the upper and lower steel pipes formed by connecting the upper and lower steel pipes to each other, and the load of the flat slab is supported mainly on the upper end face of the lower steel pipe. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a joining structure of a steel pipe column and a flat slab, in which steel pipes are sequentially connected in the vertical direction in a building and concrete is filled in the connected steel pipes.

  Regarding the joint structure of steel pipe columns filled with concrete and flat slabs in buildings, a structure is known in which a plate is protruded from the outer periphery of the steel pipe column and the flat slab is connected to the steel pipe column via this plate. It has been.

  However, according to this joining structure, as pointed out in Japanese Patent No. 3159194, a steel pipe with a large thickness is used so that both vertical load and bending moment applied to the plate can be borne by the load of the flat slab. It is necessary to adopt a wall thickness that takes into account the influence of heat when welding the plate to the steel pipe.

  In order to solve such a problem, Japanese Patent No. 3159194 discloses that a plate having a concrete through hole is interposed between upper and lower steel pipes, and the upper and lower steel pipes are connected, and the load of the flat slab is applied to the plate portion protruding outside the steel pipe. And supporting the concrete filled in the steel pipe to the plate part that protrudes to the inside of the steel pipe, thereby balancing the bending moment applied to the plate inside and outside the steel pipe, thereby preventing the bending moment from being applied to the steel pipe However, it discloses that it is possible to use a thin steel pipe.

Japanese Patent No. 3159194

  However, in the joint structure disclosed in Japanese Patent No. 3159194, in which the bending moment generated in the plate between the upper and lower steel pipes by the flat slab is canceled by the bending moment generated in the plate by the steel pipe concrete, the bending moment generated by the flat slab and the steel pipe It is actually difficult to equalize the bending moment due to the inner concrete, and it is difficult to avoid a bending moment that cannot be ignored on the steel pipe at the connecting portion of the plate.

  Accordingly, the present invention provides a joining structure of a steel pipe column and a flat slab in which steel pipes are successively connected in the vertical direction and concrete is filled in the connected steel pipe, and the bending moment is applied to the steel pipe column due to the flat slab load. It is an object of the present invention to provide a joining structure that can more reliably and sufficiently suppress the addition of the metal than the conventional one, and can be made cheaper.

  The present inventor provides a structure in which a bending moment is not applied to a steel pipe column by a flat slab load, or can be suppressed to a negligible level even when applied to a flat slab joined to a concrete-filled steel pipe column. As a result, research was continued and the following points were focused on.

That is,
(1) If all or almost all of the flat slab load is applied in the vertical direction to the upper end surface of the lower steel pipe that forms the steel pipe column part of the lower layer in the upper and lower adjacent layers, the steel pipe column is converted into a flat slab. It is possible to prevent or almost prevent the resulting bending moment from being applied,
(2) The upper steel pipe forming the steel pipe column part in the upper layer is used so that all or substantially all of the flat slab load is applied in the vertical direction to the upper end surface of the lower steel pipe forming the steel pipe column part of the lower layer. As a thing with a smaller diameter than the lower steel pipe that forms the steel pipe column part of the lower layer, a step shelf part just above the upper end surface of the lower steel pipe is formed between the upper and lower steel pipes, and the flat slab load may be supported here.
(3) The upper steel pipe forming the upper steel pipe column part has a smaller load than the lower steel pipe because the load on the upper steel pipe is less than that of the lower steel pipe forming the lower steel pipe column part. It is possible to

  The present invention is based on the above-mentioned attention, and is a joining structure of a steel pipe column and a flat slab in which steel pipes are sequentially connected in the vertical direction and concrete is filled in the connected steel pipes, and the steel pipe columns are adjacent to each other vertically. A steel pipe having an outer diameter smaller than the outer diameter of the lower steel pipe forming the lower steel pipe column portion is adopted as the upper steel pipe forming the upper steel pipe column portion in the hierarchy, and the upper and lower steel pipes are Connected via an upper steel pipe support plate having a concrete through hole, a flat slab is installed on the step shelf between the upper and lower steel pipes formed by the upper and lower steel pipe connections, and the flat slab load mainly on the upper end surface of the lower steel pipe Provides a joint structure between a steel pipe column and a flat slab.

Here, the “flat slab load” is a load to be borne by the steel pipe column among all the loads of the flat slab.
Further, the “flat slab” includes both a floor plate called a flat plate having a substantially constant thickness, and a floor plate including an edge portion that is thickened by forming a so-called support plate portion in the flat plate. .

  According to the joining structure of the present invention, the flat slab is installed on the step shelf between the upper and lower steel pipes, whereby all or substantially all of the flat slab load that the steel pipe column should bear is lowered via the upper steel pipe support plate. It is supported as a vertical load on the upper end surface of the lower steel pipe forming the steel pipe column portion of the hierarchy. Further, in the case where the upper and lower steel pipes are installed with their central axes aligned, when the upper steel pipe outer diameter is less than or equal to the lower steel pipe inner diameter, the load from the upper steel pipe passes through the upper steel pipe support plate. The concrete is mainly applied as a vertical load to the concrete filled below the support plate in the lower steel pipe. When the outer diameter of the upper steel pipe is larger than the inner diameter of the lower steel pipe, the load from the upper steel pipe is part of the upper end surface (inner circumference) of the lower steel pipe and the lower side of the support plate in the lower steel pipe via the upper steel pipe support plate It is mainly applied as a vertical load to the concrete filled in.

  Therefore, the bending moment due to the flat slab load or the like is not applied to the upper and lower steel pipes, or even if it is applied, it is negligible. Thereby, the wall thickness of the steel pipe can be reduced accordingly, and the upper steel pipe having a smaller diameter than that of the lower steel pipe can be used, thereby providing the entire joint structure at a low cost.

  The center axis lines of the upper steel pipe and the lower steel pipe connected via the upper steel pipe support plate do not necessarily need to coincide. For example, when the steel pipe columns are to be located inside the building, the central axis of the upper and lower steel pipes may be made coincident, but for the steel pipe columns along the outer wall of the building, for example, to make the outer wall flat The central axis of the upper and lower steel pipes may be shifted. Even in such a case, the flat slab is installed on the step shelf between the upper and lower steel pipes so that all or substantially all of the flat slab load that the steel pipe column should bear is transferred to the lower steel pipe via the upper steel pipe support plate. The upper end surface is supported as a vertical load. The load from the upper steel pipe is mainly applied as a vertical load to the concrete filled in the upper end surface of the lower steel pipe and / or the lower side of the support plate via the upper steel pipe support plate.

  As described above, the outer diameter of the upper steel pipe in the upper and lower adjacent layers may be equal to or less than the inner diameter of the lower steel pipe if there is no problem in terms of strength, etc., and a step that does not hinder the support of the flat slab. If a shelf part can be provided, it may be larger than the inner diameter of the lower steel pipe.

  In addition, the upper steel pipe support plate between the upper and lower steel pipes may be provided so as to provide a stepped shelf portion that supports the flat slab, and the upper steel pipe can be disposed on the inner side of the lower steel pipe, The projecting amount may be such that the stepped shelf portion can be formed, the upper steel pipe can be disposed, and a concrete through hole that does not hinder concrete filling in the steel pipe can be provided.

  The concrete can be filled into the connected steel pipe using the concrete through hole. As the hole diameter of the concrete through-hole, in order to enable smooth concrete filling using the concrete through-hole, for example, a hole having a diameter of 150 mm or more can be mentioned.

  The outer diameter of the upper steel pipe support plate may be equal to or less than the outer diameter of the lower steel pipe as long as it can provide a step shelf that does not hinder the support of the flat slab, but is used as a guide or the like in the construction of a flat slab. In some cases, the outer diameter of the lower steel pipe may be slightly larger so that a part of the flat slab load can be borne. However, if it is too large, a bending moment that cannot be ignored is generated in the overhanging portion, which may affect the steel pipe portion. As an example of the allowable amount of overhang, although it depends on the outer diameter of the lower steel pipe, the thickness (strength) of the upper steel pipe support plate, the flat slab load, etc., about 50 mm to 60 mm or less, for example, about 25 mm can be exemplified. . However, the amount of overhang is not limited to these.

In any case, an air passage hole for facilitating filling of the concrete into the steel pipe may be formed in the upper steel pipe support plate separately from the concrete passage hole.
The flat slab may be formed such that an end portion disposed on the step shelf is thicker than a portion other than the end portion in order to suppress the bending of the slab.
When adopting such thick end portions, reinforcing studs projecting on the outer peripheral surface of the upper steel pipe are arranged on the thick end portions in order to stabilize the connection with the steel pipe column. You may set up.

In order to make the joining structure of the steel pipe column and the flat slab stable, one or more penetrating reinforcing bars that penetrate the upper steel pipe and extend into the flat slab may be included.
The penetrating rebar may be a slab rebar arranged in the flat slab extending directly through the upper steel pipe, or may be a rebar prepared separately from the slab rebar in the flat slab, in the latter case May extend into the flat slab and be spliced to the slab muscle. Moreover, as a penetration reinforcing bar, it is also possible to use together what the slab reinforcement arrange | positioned in the flat slab extended as it is, and what was prepared separately, or what was further joined by the slab reinforcement.

A typical example of the case where the penetration reinforcing bar is overlapped with the slab reinforcement in the flat slab is a case where the penetration reinforcing bar is overlapped with the slab reinforcement arranged on the upper surface side of the flat slab.
In any case, when adopting a penetration reinforcing bar that is lap-joined to the slab reinforcement in the flat slab, the total cross-sectional area of the penetration reinforcement is the sum of the cross-sectional area of the slab reinforcement to which the penetration reinforcement is lap-joined. Sum of cross-sectional areas of slab bars (slab bars in positions extending through the upper steel pipe if extended as they are) facing the upper steel pipe among slab bars arranged at the same level (height) as the slab bars It is preferable to set it as the sum or more.

  In any case, when penetrating reinforcing bars are employed, the position and number of the penetrating reinforcing bars may be selected and determined so that it is not difficult to fill the concrete into the steel pipe.

  As described above, according to the present invention, the steel pipes are sequentially connected in the vertical direction, and the connecting structure of the steel pipe column and the flat slab, in which the concrete is filled in the connected steel pipe, is caused by the flat slab load. It is possible to provide a joint structure that can more reliably and sufficiently suppress the bending moment from being applied to the steel pipe column than before, and can be manufactured at a lower cost.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing an example A of a joining structure of a steel pipe column and a flat slab, and FIG. 2 is a view showing a positional relationship between upper and lower steel pipes and a support plate interposed between them as viewed from above. .
In this joining structure A, the upper steel pipe 1 forming the upper steel pipe column portion of the upper and lower layers in the steel pipe column 10 filled with the concrete 4 and the lower steel pipe column portion forming the lower layer are formed. An upper steel pipe support plate 3 is interposed between the side steel pipe 2.

The upper steel pipe 1 and the lower steel pipe 2 are welded to the support plate 3, and the upper and lower steel pipes 1 and 2 are connected via the support plate 3. The upper and lower steel pipes 1 and 2 have a rectangular cross-section that can be obtained on the market, and the upper steel pipe 1 has an outer diameter D1 in the range of the inner diameter D2 ′ of the lower steel pipe 2 or less in this example, and The one close to the inner diameter D2 ′ is employed.
The steel pipe is not limited to one having a square cross section. A circular thing etc. may be sufficient.

  The support plate 3 projects to the inner side of the lower steel pipe 2 and has a circular concrete through hole 31 having a diameter of about 150 mm in the center of the projecting portion, and a plurality of air passages formed in a distributed manner. A hole 30 is provided. The support plate 3 slightly protrudes to the outside of the lower steel pipe 2. The overhang amount α is about 25 mm in this example.

  In this example, the upper steel pipe 1 is arranged at a portion protruding to the inner side of the lower steel pipe of the support plate 3 so that the lower steel pipe 2 and the central axis CL coincide with each other. Thus, the upper steel pipe 1 is supported on the upper end surface of the lower steel pipe 2. A step shelf S is formed on the plate portion. The width of the upper end surface of the lower steel pipe 2 is the thickness of the steel pipe 2 obtained by subtracting the inner diameter D2 'from the outer diameter D2 of the steel pipe 2.

  A flat slab 5 is installed on the step shelf S. In this example, the rat slab 5 is made of reinforced concrete and includes upper reinforcing bars (upper slab bars) 51a and 51b and lower reinforcing bars (lower slab bars) 52a and 52b embedded in the slab concrete.

  The concrete 4 is filled into the steel pipes 1 and 2 by connecting a predetermined number of steel pipes for forming the steel pipe columns, and then inserting the concrete supply pipe from above into the connected steel pipes, starting from the bottom steel pipe in order. This is done by filling concrete into the bottom or by sequentially filling concrete from the bottom steel pipe to the upper steel pipe. At this time, the filling of the concrete 4 into the steel pipes 1 and 2 can be performed using the concrete through holes 31 formed in the support plate 3.

  According to the joint structure A described above, the flat slab 5 is installed on the step shelf S between the upper and lower steel pipes 1, 2, and thereby all or substantially all of the load of the flat slab 5 to be borne by the steel pipe column 10. Is supported as a vertical load on the upper end surface of the lower steel pipe 2 via the support plate 3. Further, the load from the upper steel pipe 1 is a concrete 4 ′ filled in the lower side of the support plate in the lower steel pipe 2 via the support plate 3 (more precisely, the portion protruding to the inside of the lower steel pipe of the support plate 3). Is mainly applied as a vertical load.

  Therefore, the upper and lower steel pipes 1 and 2 are not subjected to a bending moment due to the load of the flat slab 5 or the like, and even if it is applied, the bending moment is negligible. As a result, the thickness of the steel pipes 1 and 2 can be reduced by that much, and the upper steel pipe 1 has a smaller diameter than the lower steel pipe 2, so that the entire joint structure can be provided at a low cost.

In the joint structure A described above, the outer diameter D1 of the upper steel pipe 1 is equal to or smaller than the inner diameter D2 ′ of the lower steel pipe 2, but the outer diameter D1 of the upper steel pipe 1 is a step shelf that does not interfere with the support of the flat slab 5. As long as a portion can be provided, the inner diameter D2 ′ of the lower steel pipe 2 may be larger.
In this case, the load from the upper steel pipe 2 is mainly a vertical load on the concrete 4 ′ filled in a part (inner peripheral part) of the upper end surface of the lower steel pipe and the lower side of the support plate in the lower steel pipe via the support plate 3. Join as.

In any case, the bending moment resulting from the flat slab load or the like is not applied to the upper and lower steel pipes 1 and 2, or even if it is applied, the bending moment is negligible. As a result, the thickness of the steel pipes 1 and 2 can be reduced accordingly, and the upper steel pipe 1 is smaller in diameter than the lower steel pipe 2, so that the entire joint structure can be provided at low cost.
In addition, as a whole of the concrete-filled steel pipe column, and as a whole structure, the joint structure according to the present invention must be adopted for all flat slabs to be joined to the concrete-filled steel pipe column. .

  FIG. 3A shows a joining structure A ′ including a penetration reinforcing bar in the structure A shown in FIG. 1. In the structure A shown in FIG. 1, one of the upper slab bars 51 a and 51 b and the lower slab bars 52 a and 52 b of the flat slab 5 is used for further stabilization of the joining of the flat slab 5 and the steel pipe column 10. Two or more pipes may be passed through the upper steel pipe 1.

  In the example shown in FIG. 3 (A), the upper slab bars 51a and 51b are passed through the upper steel pipe 1 two by two as shown in FIG. 3 (B). Slab bars 51 a ′ and 51 b ′ between the penetrating reinforcing bars do not penetrate the steel pipe 1. In this way, the penetrating reinforcing bars are arranged so as not to hinder concrete filling.

FIG. 4A is a cross-sectional view showing still another example B of the joint structure between the steel pipe column and the flat slab. In this joining structure B, in the joining structure A ′ shown in FIG. 3 (A), in order to suppress the bending of the flat slab 5, the end portion 50 disposed on the step shelf S of the slab 5 is replaced with a portion other than the end portion. It is formed thicker than the part. Reinforcing bars 50a and 50b are also provided in the portion 50. A part (a total of four) of these reinforcing reinforcing bars 50a and 50b penetrates the upper steel pipe 1 in the same manner as the penetrating reinforcing bars 51a and 51b.
The other points are the same as those of the junction structure A ′ in FIG. 3A, and the same reference numerals as those in FIG.

  Instead of using a part of the reinforcing reinforcing bars 50a and 50b as a penetrating reinforcing bar, as shown in FIG. 4B, a reinforcing stud sd is fixed to the outer peripheral surface of the lower end of the upper steel pipe 1 by welding and protruding. Alternatively, it may be embedded in the end portion 50 formed thick. It is also possible to employ such a stud sd and allow a part of the reinforcing reinforcing bars 50a and 50b to penetrate the steel pipe 1.

  FIG. 5 is a cross-sectional view showing still another example C of the joining structure of the steel pipe column and the flat slab, and FIG. 6 shows the positional relationship between the upper rebar of the flat slab and the upper steel pipe in the joining structure C as viewed from above. FIG.

  This joining structure C is a part of the slab bars 51a and 51b in the flat slab 5 in order to make the joining structure of the steel pipe column 10 and the flat slab 5 more stable in the joining structure B shown in FIG. Instead of penetrating through the upper steel pipe 1, reinforcing bars 53a and 53b having a cross-sectional area of 1.5 times or more of that of the slab reinforcing bars 51a (51b) are employed as the penetrating reinforcing bars. The other points are the same as those of the bonding structure B in FIG. 4A, and the same reference numerals as those in FIG.

  As shown in FIG. 6, none of the slab bars 51 a and 51 b in the flat slab 5 penetrates the upper steel pipe 1. On the other hand, two reinforcing bars 53a, 53b extend through the upper steel pipe 1 into the flat slab. The penetration reinforcing bar 53a is overlapped with the slab reinforcement 51a, and the penetration reinforcing bar 53b is overlapped with the slab reinforcement 51b.

  The total cross-sectional area of the penetrating rebars 53a and 53b (four in total) is the slab reinforcing member 51a and 51b in the flat slab 5, which is the slab reinforcing member facing the steel pipe 1, that is, the position penetrating the steel pipe 1 if extended as it is. It is more than the sum total of the cross-sectional areas of the slab muscles 51a and 51b (total 6). Note that the slab bars facing the steel pipe 1 include slab bars 51a and 51b in which the penetrating reinforcing bars 53a and 53b are overlapped, and slab bars 51a and 51b arranged therebetween, as can be seen from FIG. .

  In the joint structure described above, the central axes of the upper steel pipe 1 and the lower steel pipe 2 are matched, but the central axes of the steel pipes 1 and 2 may be shifted. FIG. 7 shows an example A ″ of a joining structure in such a case. The joining structure A ″ is a joint structure A ′ shown in FIG. 3 (A), in the outer surface of the upper steel pipe 1 and the lower steel pipe 2. A part of the outer surface of the steel pipe is made to coincide with the center axis of the steel pipes 1 and 2 being shifted so that a part of the steel pipe pillar is arranged at a position along the predetermined position W of the outer wall surface of the building where the steel pipe column is to be erected. It is.

  Also in this joining structure A ″, the flat slab 5 is installed on the step shelf S between the upper and lower steel pipes 1 and 2 so that all or substantially all of the flat slab load to be borne by the steel pipe column 10 is supported by the upper steel pipe. A vertical load is supported on the upper end surface of the lower steel pipe 2 via the plate 3. Further, the load from the upper steel pipe 1 is supported on the upper end surface of the lower steel pipe 2 and below the support plate via the upper steel pipe support plate 3. It is mainly applied as a vertical load to the concrete 4 'filled on the side.

  The present invention can be used for building construction in which a flat slab is joined to a concrete-filled steel pipe column.

It is sectional drawing which shows one example of the joining structure of a steel pipe column and a flat slab. It is a figure which sees the positional relationship of the upper and lower steel pipes in the joining structure shown in FIG. 1, and the support plate interposed between them from upper direction. FIG. 3A is a cross-sectional view showing another example of a joining structure between a steel pipe column and a flat slab, and FIG. 3B is a view showing a state in which the slab bars penetrate the steel pipe as viewed from above. is there. FIG. 4A is a cross-sectional view showing still another example of the joining structure between the steel pipe column and the flat slab, and FIG. 4B is a plan view of a part of the joining structure using the stud. It is sectional drawing which shows the further another example of the joining structure of a steel pipe column and a flat slab. It is a figure which shows the positional relationship of the upper rebar and penetration rebar of a flat slab in the joining structure of Drawing 5, and an upper steel pipe from the upper part. It is sectional drawing which shows the further another example of the joining structure of a steel pipe column and a flat slab.

Explanation of symbols

A, A ', A ", B, C Joint structure of steel pipe column and flat slab 10 Steel pipe column 1 Upper steel pipe D1 Outer diameter 2 of steel pipe 1 Lower steel pipe D2 Outer diameter D2' of steel pipe 2 Inside diameter 3 of steel pipe 2 Upper side Steel pipe support plate 31 Concrete through hole 4, 4 'Concrete S Step shelf 5 Flat slab 51a, 51b Upper rebar of slab 5 (upper slab rebar)
52a, 52b Lower rebar of slab 5 (lower slab rebar)
50 Thick end portions 50a and 50b of the slab 5 Reinforcing bar sd Reinforcing studs 53a and 53b Through-bar reinforcing bar W

Claims (9)

  A steel pipe column in which steel pipes are successively connected in the vertical direction, and a concrete structure is filled with the steel pipe column and a flat slab. The steel pipe column portion of the upper layer in the upper and lower layers of the steel pipe column A steel pipe having an outer diameter smaller than the outer diameter of the lower steel pipe forming the lower steel pipe column portion is adopted as the upper steel pipe forming the upper steel pipe, and the upper and lower steel pipes have concrete through holes. A steel pipe column connected through a plate, a flat slab is installed on a step shelf between the upper and lower steel pipes formed by the upper and lower steel pipe connections, and the flat slab load is supported mainly on the upper end surface of the lower steel pipe; Flat slab joint structure.   The steel pipe column and flat slab joining structure according to claim 1, wherein the upper steel pipe and the lower steel pipe are connected to each other through the upper steel pipe support plate so that the central axes of the steel pipes coincide with each other.   The joining structure of a steel pipe column and a flat slab according to claim 1 or 2, wherein the upper steel pipe support plate projects from the lower steel pipe.   The said flat slab is the joining structure of the steel pipe pillar and flat slab of Claim 1, 2, or 3 by which the edge part arrange | positioned at the said level | step-difference shelf part is formed thicker than parts other than this edge part.   The steel pipe column / flat slab joining structure according to claim 4, wherein a reinforcing stud protruding from an outer peripheral surface of the upper steel pipe is disposed at the thick end portion.   The steel pipe column and flat slab joining structure according to any one of claims 1 to 5, comprising one or more penetrating reinforcing bars that penetrate through the upper steel pipe and extend into the flat slab.   The joint structure of a steel pipe column and a flat slab according to claim 6, wherein all or part of the penetrating rebar is lap-joined to a slab bar in the flat slab.   The joint structure of a steel pipe column and a flat slab according to claim 7, wherein the slab bar to which the penetration reinforcing bar is lap-joined is a slab bar arranged on the upper surface side of the flat slab. The sum of the cross-sectional areas of the penetrating reinforcing bars joined to the slab bars in the flat slab is the same as the sum of the sectional areas of the slab reinforcing bars to which the penetrating reinforcing bars are joined. The steel pipe column / flat slab joint structure according to claim 7 or 8, wherein the joint structure is equal to or greater than a sum of cross-sectional areas of slab bars facing the upper steel pipe.