JP2008101419A - Connection between steel pipe column and flat slab - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connection between a steel pipe column and a flat slab, which is constructed by penetrating the steel pipe column into the flat slab having an almost even thickness over the entire area, wherein the amount of steel products necessary for reinforcing an area around the steel pipe column can be reduced, to thereby enhance pipe arrangement efficiency around the steel pipe column. <P>SOLUTION: According to the structure of the connection, shear reinforcements 2 are projected from a peripheral surface of the steel pipe column 1 in parallel with slab reinforcements 4 in the range of the thickness of the flat slab 3 to be connected to the steel pipe column 1, and then anchored into the flat slab 3. If necessary, strengthening reinforcements 5 each having an upper edge reinforcement 51 and a lower edge reinforcement 52 are arranged in the flat slab 3 around the steel pipe column 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a joint between a steel pipe column and a flat slab in which the steel pipe column penetrates a flat slab having a substantially uniform thickness over the entire surface.

  The flat slab structure has the advantage that the floor height is suppressed by the absence of beams, but in order to ensure the safety against punching shear failure of the floor slab, in principle, the flat slab structure around the steel pipe column A support plate or capital is often formed on the lower surface side. However, the formation of the support plate and the like loses the effect of reducing the floor height and is disadvantageous in that the construction becomes complicated. Therefore, it is desirable not to form the support plate or the like from the viewpoint of floor height reduction and workability.

  In addition, it is difficult to process the horizontal shearing force at the joints when the steel pipe column is divided into upper and lower parts with a flat slab sandwiched between them. In addition to difficulties, cross-sectional defects in steel pipe columns must be taken into account, both of which have problems.

  From the above, it is reasonable that the joint is a type in which the steel pipe column penetrates the flat slab of almost uniform thickness over the entire surface and is completed by reinforcement around the steel pipe column. Is.

  In order to transmit the bending moment and shearing force from the flat slab to the steel pipe column at the joint while satisfying these conditions, a bracket having a flange usually protrudes around the steel pipe column. (See Patent Documents 2 and 3). Among the brackets, horizontal plates (flanges) are aligned on the upper and lower surfaces of the flat slab or in the vicinity thereof, and have the role of transmitting the bending moment and shear force from the flat slab to the steel pipe column.

  However, projecting the bracket around the steel pipe column requires a large amount of steel material, which increases the manufacturing cost of the steel pipe column. In addition, the extension of the bracket to the flat slab side limits the connection with the slab muscle, so the slab reinforcement in the field is complicated, for example, the slab reinforcement must be laid through the bracket. Therefore, the workability is likely to deteriorate.

  On the other hand, flanges (鍔) that are vertically aligned on the outer peripheral surface of the steel pipe column are projected, and reinforcing bars (connecting bars, etc.) are projected radially from each flange to reduce interference with the slab bars. There is a method for reducing the inhibition of muscle placement work (see Patent Document 4).

JP 2004-197389 A (FIG. 1) JP 2000-160685 A (Claim 1, paragraphs 0021 to 0022, FIGS. 1 and 2) JP 2003-90097 (Claim 1, paragraphs 0008 to 0009, FIGS. 1 to 5) JP 2002-70164 A (Claim 1, paragraphs 0009 to 0013, FIGS. 1 to 8)

  In Patent Document 4, reinforcing bars such as connecting bars projecting around a steel pipe column are buried in concrete, thereby transmitting a bending moment and a shearing force with a flat slab. However, since the reinforcing bars protrude radially from the steel pipe column, the tensile force from the slab bars is not transmitted as the axial tensile force of all the reinforcing bars, so the stress transmission between the flat slab and the steel pipe column through the reinforcing bars is sufficient. May not be done. For this reason, it is necessary to devise arrangement of the slab muscles by engaging the connecting bars and the like so that a tensile force is transmitted between them (FIGS. 1 and 5).

  In addition, if the amount of reinforcing bars protruding from the steel pipe column is increased for the purpose of smooth stress transmission by the reinforcing bars, the reinforcing bars will be mixed near the steel pipe columns, thereby inhibiting the filling of the concrete and forming voids in the concrete. It becomes easy.

  In view of the above background, the present invention proposes a joint between a steel pipe column and a flat slab that uses a small amount of steel material and has good barbing workability around the steel pipe column.

  According to a first aspect of the present invention, in the joining portion between the steel pipe column and the flat slab, a shear reinforcing material projects in parallel with the slab bar on the outer peripheral surface of the steel pipe column in the range of the thickness of the flat slab joined to the steel pipe column. It is a constituent requirement that it is fixed in the flat slab. Claim 1 is directed to a flat slab having a substantially uniform thickness over the entire surface and having no support plate or capital.

  One or a plurality of shear reinforcements are provided so as to protrude from the outer peripheral surface of the steel pipe column. In the case of a plurality of the shear reinforcements, they are provided at intervals in the height direction. Even in the case of one, when the shear reinforcing material itself is bent into, for example, a U shape, the parallel portions protrude substantially at intervals in the height direction.

  The shear reinforcement acts to transmit the shearing force from the flat slab to the steel pipe column, and is provided on the outer peripheral surface of the steel pipe column in parallel with the slab bar, so that the tensile force from the slab bar is between the concrete and the concrete. Through the adhesive force, the shear reinforcement can bear as an axial tensile force. For this reason, it becomes possible to fully transmit the tensile force from the slab reinforcement of each direction to a steel pipe pillar, and it becomes possible to suppress generation | occurrence | production of the crack to concrete. When the steel pipe column is a square steel pipe, a shear reinforcement member is provided so as to protrude in parallel with a slab bar perpendicular to the surface for each surface.

  Since the shear reinforcement is parallel to the slab reinforcement, the interval between the shear reinforcements adjacent in the horizontal direction can be made constant. As a result, since the shear reinforcement material is not concentrated near the steel pipe column as in the case of radial arrangement, the filling property of the concrete is not hindered. In addition, since the shear reinforcement material can be arranged so as not to cause interference with the slab reinforcement, it is possible to fill the concrete of the flat slab densely.

  In addition, since the reinforcement for the steel pipe column only needs to be provided with a shear reinforcement, the amount of steel used can be reduced compared to the case where a bracket or the like is provided, so that the manufacturing cost of the steel pipe column is reduced. When manufacturing a steel pipe column with shear reinforcement, it is only necessary to weld the shear reinforcement individually to the surface of the steel pipe column, so when welding multiple types of steel materials or by penetrating the steel pipe columns There is no complicated manufacturing process as in the case of integrating them.

  A stud bolt, a reinforcing bar, a shape steel, etc. are used for a shear reinforcement material, The form is not ask | required. When the reinforcement around the steel pipe column is not sufficient only by projecting the shear reinforcement material to the steel pipe column, the flat slab around the steel pipe column has an upper end bar and a lower end bar as described in claim 2. Reinforcing bars are placed. The reinforcing steel bars are arranged between the upper and lower main bars of the flat slab.

  Cracks in concrete in a flat slab due to horizontal shearing force, etc. are on the plane, in a diagonal direction of a quadrilateral defined by four steel pipe columns, or in a direction inclined by 45 degrees with respect to a straight line connecting the centers of adjacent steel pipe columns. There is a tendency to occur. For this reason, it is appropriate that the reinforcing reinforcing bars are arranged so as to resist the tensile force that generates the cracks in the diagonal direction or 45 degrees, and the reinforcing reinforcing bars are resistant to cracking by resisting this tensile force. It works to suppress the occurrence.

  Covers an area that is long enough to be anchored in the flat slab and that can resist the tensile forces that cause the flat slab to crack together, as in the case where the shear reinforcement is a reinforcing bar. In some cases, it is not always necessary to add reinforcing bars.

  When a reinforcing bar is used as the shear reinforcement, it is appropriate that the shear reinforcement is connected to the slab bar so that the tensile force can be sufficiently transmitted to the slab bar by an adhesive force or the like. For example, in the case where the shear reinforcement material has a portion arranged along the upper and lower main bars of the slab reinforcement, the shear reinforcement material is applied to the upper and lower main reinforcements in the flat slab as described in claim 3. By overlapping, the transmission effect of the tensile force between the slab reinforcement and the shear reinforcement due to the adhesive force is increased, so that the transmission of the tensile force from the slab reinforcement is surely easily performed.

  By projecting the shear reinforcement material on the outer peripheral surface of the steel pipe column parallel to the slab bar, the shear force from the flat slab is transmitted to the steel pipe column and the tensile force from the slab bar is applied to the shear reinforcement in the axial direction. Therefore, the shearing force in each direction and the tensile force from the slab bar can be sufficiently transmitted to the steel pipe column.

  In addition, since the steel pipe column only needs to be provided with a shear reinforcement material, the amount of steel used can be reduced compared to the case where a bracket or the like is provided, reducing the manufacturing cost of the steel tube column and arranging it around the steel tube column. Muscle workability can be improved.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  In FIG. 1, in the range of the thickness of the flat slab 3 to be joined to the steel pipe column 1, a shear reinforcing material 2 protrudes in parallel with the slab bar 4 on the outer peripheral surface of the steel pipe column 1 and is fixed in the flat slab 3. A concrete example of the joint part between the steel pipe column and the flat slab is shown. (A) is a top view, (b) is a sectional arrow view of the AA line of (a).

  Since the shear reinforcement material 2 is projected in parallel with the slab bar 4, a square steel pipe is mainly used for the steel pipe column 1 for the convenience of projecting perpendicularly to the outer peripheral surface of the steel pipe column 1. The steel pipe column 1 is filled with concrete, mortar, or the like, and the steel pipe column 1 may constitute a CFT column.

  As shown in FIG. 1- (a), the slab bars 4 are arranged in a lattice pattern in two directions, and the shear reinforcement 2 faces in a direction parallel to the slab bars 4 in each direction. Since the shear reinforcement material 2 is disposed so as not to interfere with the slab bar 4, the tip of the slab bar 4 that intersects the steel pipe column 1 can be brought close to the vicinity of the outer peripheral surface of the steel pipe column 1. As a result, the overlap length between the slab reinforcement 4 and the shear reinforcement 2 can be secured without taking a large projecting length of the shear reinforcement 2 from the steel pipe column 1. It is easy to transmit the tensile force to 2.

  FIG. 1 particularly shows the case where a stud bolt is used as the shear reinforcement 2. In this case, as shown in FIG. 1- (b), the shear reinforcement material 2 is spaced in the height direction, and protrudes at the level of the upper main bar 41 and the level of the lower main bar 42 of the slab bar 4 and the level between them. Is done. In the drawing, one shear reinforcement member 2 is provided at a level intermediate between the upper main bar 41 and the lower main bar 42, but the number of shear reinforcement members 2 arranged in the height direction is flat and flat with the thickness of the shear reinforcement member 2 itself. It is adjusted according to the thickness of the slab 3.

  In the drawing, in consideration of the filling property of the concrete of the flat slab 3, the distance between the upper main bars 41 and 41 (lower main bars 42 and 42) adjacent to each other on the plane and the space between the shear reinforcements 2 and 2 adjacent in the horizontal direction are also shown. Are equal, the shear reinforcement 2 is positioned in the middle of the slab reinforcement 4, and both are arranged alternately. By providing a space between the shear reinforcement 2 and the slab reinforcement 4, the concrete is easily filled, and an adhesion force between the two concretes can be easily obtained.

  In the case of FIG. 1, the shear reinforcement material 2 is attached to each surface of the steel pipe column 1, that is, to each direction of the slab reinforcement 4 that is abutted against the outer peripheral surface of the steel pipe column 1, and a plurality of shear reinforcements 2 are arranged in each of the horizontal direction and the height direction By gathering, the shear force and bending moment from the flat slab 3 are transmitted to the steel pipe column 1.

  The tensile force from the upper main bar 41 and the lower main bar 42 is transmitted to the shear reinforcement member 2 through the adhesion force between the surrounding concrete and the flat slab 3 to the steel pipe column 1. By transmitting the tensile force, the bending moment can be transmitted between the flat slab 3 and the steel pipe column 1.

  In FIG. 1, reinforcing reinforcing bars 5 having upper end bars 51 and lower end bars 52 are arranged around the steel pipe column 1 in order to reinforce cracks that may occur in the flat slab 3. The upper end bars 51 and the lower end bars 52 restrain the concrete around the steel pipe column 1 and are connected by some means so as to form a pair in the upper and lower sides and restrain each other to restrain the cracks of the flat slab 3.

  In FIG. 1, as shown in FIG. 1B, the lattice line 53 is arranged between the upper end line 51 and the lower end line 52 and welded to both ends to connect the upper end line 51 and the lower end line 52, but both ends are bent. The connecting means of the upper end muscle 51 and the lower end line 52 is not limited, for example, the hook line is engaged with the upper end line 51 and the lower end line 52. In FIG. 1- (b), in order to constrain the deformation between the end portions of the upper end muscle 51 and the lower end muscle 52, a connecting member 54 is installed. Since the reinforcing steel bars 5 are arranged so as to intersect the slab bars 4 as shown in FIG. 4A, the distance between the upper bars 51 and the lower bars 52 is the upper main bars of the flat slab 3 as shown in FIG. It is smaller than the distance between 41 and the lower main reinforcement 42.

  Cracks of the flat slab 3 are easily generated radially from the steel pipe column 1 and, as described above, are inclined at 45 degrees with respect to a straight line (in the direction of the slab bar 4) connecting the adjacent steel pipe columns 1 and 1 on a plane. Or since it tends to appear prominently in a direction close to it, as a general rule, as shown in FIG. 1- (a), the reinforcing steel bars 5 are arranged in a direction perpendicular to the 45 degree direction. Since the reinforcing reinforcing bars 5 are fixed in the concrete over the entire length, they can resist the tensile force that causes cracking alone, so the ends of the reinforcing reinforcing bars 5 and 5 in the orthogonal direction do not necessarily have to be connected. May be linked.

  In FIG. 1, in order to increase the reinforcing effect by the reinforcing reinforcing bars 5, a plurality of wires are arranged at intervals in the direction of 45 degrees from the steel pipe column 1. The reinforcing reinforcing bars 5 are formed in a straight line on a plane in order to resist the tensile force in the axial direction of the upper and lower reinforcing bars 51 and 52.

  FIG. 2 shows a case where a reinforcing bar is used as the shear reinforcement 2. Also in this case, the shear reinforcement material 2 is projected on the outer peripheral surface of the steel pipe column 1 as in the case of the stud bolt, and a plurality of each of the surfaces of the steel pipe column 1 are assembled in each of the horizontal direction and the height direction, Shear force and bending moment from the flat slab 3 are transmitted to the steel pipe column 1. In the case of a reinforcing bar, since the total length of the shear reinforcement member 2 can be made larger than that of a stud bolt, the effect of transmitting the tensile force from the upper end principal bar 41 and the lower end principal bar 42 to the shear reinforcement member 2 can be enhanced.

  Also in FIG. 2, the interval between the adjacent upper main bars 41 and 41 (lower main bars 42 and 42) and the interval between the shear reinforcing materials 2 and 2 adjacent in the horizontal direction are made equal. However, the shear reinforcement material 2 may be positioned so as to overlap the upper main bar 41 and the lower main bar 42 as shown in FIG. As in FIG. 1, the shear reinforcements 2 are arranged in three stages in the height direction, but the number of arrangements in the height direction is adjusted according to the thickness of the shear reinforcement 2 itself and the thickness of the flat slab 3. Is done.

  When a reinforcing bar is used as the shear reinforcement 2, the length of the shear reinforcement 2 can be made longer than that in FIG. 1 as shown in FIG. The concrete can be restrained and reinforced. Therefore, in the case of FIG. 2, it is not always necessary to arrange the reinforcing reinforcing bars 5. However, as shown by the two-dot chain line in FIG. Sometimes.

  FIG. 3 shows a case where a U-shaped reinforcing bar bent in a U-shape is used as the shear reinforcement 2. In this case, the shear reinforcement material 2 is composed of opposing leg portions 2a, 2a and an intermediate portion 2b positioned therebetween, and is welded to the outer peripheral surface of the steel pipe column 1 at the intermediate portion 2b. The shear reinforcement member 2 is arranged in a vertical plane so that the shearing force from the flat slab 3 and the tensile force from the upper and lower main bars 41 and 42 are transmitted to the upper and lower legs 2a and 2a. In the case of FIG. 3, the parallel leg portions 2a and 2a are arranged at intervals in the height direction.

  In FIG. 3, since the length of the leg 2a is smaller than the length of the shear reinforcement 2 in FIG. 2, in order to increase the effect of transmitting the tensile force from the upper main bar 41 and the lower main bar 42 to the shear reinforcement 2, The portions 2a and 2a are overlapped with the upper main bar 41 and the lower main bar 42 so as to be connected as a lap joint. The leg 2a may be completely separated from the upper main bar 41 and the lower main bar 42 or may be somewhat separated. When the leg portion 2a has a length equivalent to that of the shear reinforcement member 2 shown in FIG. 2, the leg portion 2a may be positioned in the middle of the upper main bars 41 and 41 (lower main bars 42 and 42) adjacent in the horizontal direction. .

  Also in FIG. 3, when the leg portion 2a has a length equivalent to that of the shear reinforcement member 2 in FIG. 2 and can exert the effect of a reinforcing bar as the shear reinforcement member 2 in FIG. Although it is not necessary to arrange the reinforcing bars, reinforcing reinforcing bars 5 may be arranged as shown by a two-dot chain line in FIG. When the reinforcing reinforcing bars 5 are arranged, interference with the reinforcing reinforcing bars 5 is avoided because the leg portions 2a and 2a facing each other in FIG. 3 are open.

  In the case of FIG. 3, the shear reinforcement member 2 has a shape in which legs 2 a corresponding to the shear reinforcement member 2 in FIG. 2 are arranged in two steps in the height direction. Since a plurality of them are arranged in each of the height directions, they gather to function to transmit the shearing force and bending moment from the flat slab 3 to the steel pipe column 1.

  FIG. 4 shows a case where the reinforcing reinforcing bars 5 shown in FIG. 1 are arranged in parallel with the slab bars 4 in two directions and in parallel in the horizontal direction. Since the tensile force that generates cracks in the flat slab 3 is divided into components parallel to the slab bars 4 in two directions, the reinforcing bars 5 are arranged in a combined manner in two directions parallel to the slab bars 4. However, it will be able to resist the tensile force that causes cracks.

  In order to effectively resist the tensile force that generates cracks, it is appropriate that the reinforcing steel bars 5 are disposed closer to the steel pipe column 1 as shown in the figure, but the steel pipes are provided so as not to interfere with the shear reinforcement 2. It may be arranged at a position away from the outer peripheral surface of the column 1. Here, the reinforcing reinforcing bar 5 is composed of the upper reinforcing bar 51 and the lower reinforcing bar 52, but the lattice reinforcing bar 53 is replaced with the hook reinforcing bar according to the presence or absence of interference with the shear reinforcing material 2.

(A) is the top view which showed the reinforcement arrangement | positioning state of the junction part at the time of using a stud bolt as a shear reinforcement, (b) is the sectional view on the AA line of (a). (A) is the top view which showed the bar arrangement state of the junction part at the time of using a reinforcing bar as a shear reinforcement, (b) is the BB sectional view taken on the line of (a). (A) is the top view which showed the bar arrangement state of the junction part at the time of using a U-shaped reinforcing bar as a shear reinforcement, (b) is CC sectional view taken on the line of (a). (A) is the top view which showed the reinforcement arrangement | positioning state of the junction part at the time of arranging the reinforcement reinforcing bar shown in FIG. 1 in parallel with a slab reinforcement, (b) is the DD sectional view taken on the line of (a). is there.

Explanation of symbols

1 ......... Steel column 2 ......... Shear reinforcement 2a ... Leg 2b ... Intermediate part 3 ......... Flat slab 4 ......... Slab reinforcement 41 ... Upper main bar 42 ... Lower end main bar 5 ......... Reinforcement Reinforcing bars 51 …… Top bars 52 …… Bottom bars 53 …… Lattice bars 54 …… Connecting material

Claims (3)

  In the range of the thickness of the flat slab to be joined to the steel pipe column, a steel pipe is characterized in that a shear reinforcement is projected in parallel with the slab bar on the outer peripheral surface of the steel pipe column and fixed in the flat slab. Joint between column and flat slab.   The joint part of a steel pipe column and a flat slab according to claim 1, wherein reinforcing bars having upper and lower end bars are arranged in the flat slab around the steel pipe column. The joint part of the steel pipe column and flat slab of Claim 1 with which the said shear reinforcement material has overlapped with the upper end main reinforcement and the lower end main reinforcement in the said flat slab.

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