JP4943795B2 - Joint between steel pipe column and flat slab - Google Patents

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 due to the absence of beams, but on the other hand , in order to ensure the safety against punching shear failure, in principle, it is supported on the lower surface side of the flat slab around the steel pipe column. Plates or capital are often formed. 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, when the steel pipe column is divided into upper and lower parts with a flat slab sandwiched, it becomes difficult to treat the horizontal shearing force at the joint, and the reinforcement across the inside and outside of the steel pipe column becomes extremely difficult, and the construction of the steel pipe column is extremely difficult. Column cross-sectional defects must be taken into account, both of which have problems.

  From the above, it is appropriate that the joining portion is of a type in which the steel pipe column penetrates a flat slab having a substantially uniform thickness over the entire surface and completed by reinforcement around the steel pipe column.

  In order to ensure that the bending moment and shear force from the flat slab are transmitted to the steel pipe column at the joint while satisfying these conditions, a bracket is usually provided around the steel pipe column (patented). References 1 and 2). Among the brackets, horizontal plates 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 horizontal shearing 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. Further, since the bracket extends to the flat slab side, the connection with the slab bar is limited, so that the workability of the slab bar at the site is complicated, and 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 3).

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 3, a loop-shaped connecting bar is welded to a flange protruding from the outer peripheral surface of a steel pipe column, and a slab bar is inserted into the connecting bar, so that the joint between the steel pipe column and the flat slab is removed from the flat slab. Yield strength against vertical shearing force is secured (paragraphs 0006, 0009 to 0011).

  However, in transmitting the vertical shear force from the flat slab to the steel pipe column, the slab muscle is engaged with the connecting muscle by inserting the slab muscle into the connecting muscle, and transmitted from the connecting muscle to the heel. The connecting bars are densely arranged around the steel pipe column, and the reinforcing bars are mixed. As a result, the filling property of the concrete around the steel pipe column is lowered, and there is a possibility that voids are formed in the concrete.

  In addition, the heel of Patent Document 3 bears the vertical shearing force as a supporting pressure, but the vertical shearing force from the concrete of the flat slab is directly transmitted as an adhesive force to the connecting bars protruding from the heel. In order to secure a good adhesion, it is necessary to arrange many connecting bars.

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

The joint part of the steel pipe column and the flat slab according to claim 1, in the range of the thickness of the flat slab to be joined to the steel pipe column, the perforated divel faces at least two directions with respect to the outer peripheral surface of the steel pipe column , It is arranged while maintaining a fixed state, penetrating rebars are arranged in the flat slab through the through hole of the perforated dowel, and a plurality of the perforated dowels are combined to surround the steel pipe column. This is a component requirement. Claim 1 is directed to a flat slab having a substantially uniform thickness over the entire surface and having no support plate or capital.
The joint between the steel pipe column and the flat slab according to claim 3 is arranged so that the perforated gibber is placed between an upper main bar and a lower main bar that are slab bars arranged in the flat slab. This is a component requirement.

  The perforated gibber need only be able to maintain the state fixed to the outer peripheral surface of the steel pipe column to the extent that it can bear the vertical shearing force from the flat slab. Including the case where When the perforated diver faces in at least two directions, the penetrating rebar is also arranged in the flat slab in at least two directions. Two directions refer to two horizontal directions.

  The penetrating rebar is inserted into the perforated gibber projecting from the outer peripheral surface of the steel pipe column, and the penetrating rebar is placed in the flat slab around the steel pipe column. Then, it is transmitted from the penetrating rebar to the perforated gibber and from the perforated gibber to the steel pipe column. In addition, since the perforated gibber is embedded in the concrete of the flat slab, the perforated gibber directly acts to transmit the shearing force from the concrete to the steel pipe column.

  The insertion hole of the perforated diver through which the penetration rebar penetrates is formed larger than the diameter of the penetration rebar. The perforated gibber is buried in the concrete of the flat slab, so that the adhesion force on the surface of the perforated gibber and the supporting pressure corresponding to the horizontal projected area of the insertion hole are exerted as resistance to the shearing force. In addition, the shear strength of the concrete existing in the insertion hole on the same plane as the surface of the perforated gibber and the shear strength of the penetrating rebar that penetrates the insertion hole are added as shear resistance. The resistance to vertical shearing force is greater than when relying solely on the applied force.

  Tensile force from the slab bar is transmitted to the penetrating rebar in the crossing direction parallel to or perpendicular to the slab bar via the adhesive force between the concrete and the steel bar through the perforated gibber. Is done. When multiple penetrating rebars are gathered to surround the steel pipe column, the penetrating rebar located on the working side of the tensile force, the penetrating rebar located on the opposite side of the steel pipe column, and the perforated gibber Tensile force is transmitted to the steel pipe column.

  In order to reinforce around the steel pipe column, a perforated gibber is protruded around the steel pipe column, and only the penetrating rebar is placed through the perforated gibber, so the shear force transmission members close to the steel pipe column. Therefore, it does not hinder the filling of concrete. In addition, since the perforated gibber and the penetrating rebar can be arranged so as not to cause interference with the slab reinforcement, it is possible to fill the flat slab concrete densely.

  In addition, since the reinforcement around the steel pipe column only requires the arrangement of perforated gibbles and penetrating reinforcing bars, the amount of steel used can be reduced compared to the case where a bracket or the like is protruded around the steel pipe column, so the production of the steel pipe column Cost is reduced. It is reasonable to weld the perforated gibel in advance to the steel pipe column before carrying it to the site, but even if it is pre-welded, the projecting width from the outer peripheral surface of the steel pipe column can be suppressed. Obstructing workability such as reinforcement and concrete filling is avoided.

As described above, the perforated gibber is joined to the outer periphery of the steel pipe column by welding, bolts, or using frictional force. When mainly using the frictional force , a plurality of pieces are combined to surround the steel pipe column. By this, the state fixed to the steel pipe column is maintained.

When using the frictional force , the perforated gibber is driven by a wedge or the like between it and the steel pipe column. The fixed state is maintained by the friction force. In this case , since neither welding nor bolts are used for fixing the perforated gibber, there is no problem of occurrence of residual stress in the steel pipe column due to welding heat and cross-sectional defects due to the formation of bolt insertion holes.

The slab in which the perforated dive bar is arranged in the flat slab as described in claim 2 , when the perforated dive bar is fixed around the steel pipe column and the reinforcement of the penetrating rebar is not sufficient for reinforcement around the steel pipe column. The reinforcing bars are arranged in the direction that intersects the bars and the direction that the penetrating reinforcing bars cross the slab bars.

Cracks in concrete in a flat slab due to horizontal shearing force tend to occur in the diagonal direction of a quadrilateral defined by four steel pipe columns on a plane. In order to suppress the occurrence of cracks in the diagonal direction, it is appropriate to dispose the penetrating rebar so as to resist the tensile force that generates the crack, and the penetrating rebar of claim 2 crosses the slab bar, Resistes tensile force and acts to suppress cracking.

Also in Claim 1 , if the protruding width of the perforated gibel from the steel pipe column can be increased and the penetration reinforcing bars can be arranged in parallel in the horizontal direction, a large number of penetration reinforcing bars can be arranged around the steel pipe column. become. For this reason, even if it does not cross a penetration reinforcement to a slab reinforcement, it is possible to give reinforcement which can resist the tensile force which generates a crack around a steel pipe pillar.

  By penetrating through a rebar through a perforated gibber projecting on the outer peripheral surface of a steel pipe column and arranging the through rebar in the flat slab around the steel pipe column, the vertical shear force from the flat slab is perforated from the through rebar. While transmitting to the steel pipe column through the gibber, the perforated gibber can directly transmit to the steel pipe column while bearing the vertical shearing force.

  A perforated gibber protrudes around the steel pipe column and only penetrates through the perforated gibber so that the penetrating rebar is placed. There is no hindrance. Further, since the amount of steel used is reduced compared to the case where a bracket or the like is provided around the steel pipe column, the manufacturing cost of the steel pipe column can be reduced.

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

  FIG. 1 shows that in the range of the thickness of a flat slab 4 to be joined to a steel pipe column 1, the perforated gibel 2 is kept fixed in at least two directions with respect to the outer peripheral surface of the steel pipe column 1. 2 shows a specific example of a joint between a steel pipe column and a flat slab in which a penetrating rebar 3 is arranged in the flat slab 4 through the two insertion holes 2a. (A) shows a plane, (b) shows a cross section taken along line AA of (a).

  In the drawing, a case where a square steel pipe is used as the steel pipe column 1 is shown. However, the steel pipe column 1 may be a circular steel pipe, and in this case, the perforated gibber 2 is fixed in at least two directions on the plane. The steel pipe column 1 is filled with concrete, mortar, or the like, and the steel pipe column 1 may constitute a CFT column. In addition to a steel plate (plate) as shown in the figure, an H-shaped steel, a T-shaped steel, or the like is used for the perforated gibber 2, and in the case of a shaped steel, the web is arranged in a vertical plane. For example, T-shaped steel is used in a form in which the flange is located on the lower side of the web in order to obtain the effect of concrete support by the flange.

  As shown in FIG. 1- (a), the slab bar 5 is laid out in a lattice pattern in two directions, and the perforated gibber 2 has an upper end main bar 51 which is a slab bar 5 and a lower end on the longitudinal section as shown in FIG. It arrange | positions so that it may fit between the main muscles 52. Since the perforated gibber 2 is placed between the upper main bar 51 and the lower main bar 52, there is no interference between the penetrating rebar 3 and the slab bar 5. Therefore, the penetrating bar 3 is overlapped with the slab bar 5 on the plane. can do. When the steel pipe column 1 is a circular steel pipe, the penetrating rebar 3 is arranged at an angle of 45 degrees, for example, in a direction intersecting the slab bar 5. In this relation, in the case of a circular steel pipe, the perforated divel 2 is arranged in parallel to each other on both sides of the center line of the circular steel pipe, which is parallel to the two-way penetration rebar 3.

  FIG. 1 shows a case in which a plurality of through holes 2a formed in the height direction are arranged in a row with a perforated dive 2 attached to each corner of a steel pipe column 1 (square steel pipe) and oriented in two horizontal directions. is there. In order to support the penetrating rebar 3 with respect to the surface (flange) of each direction of the steel pipe column 1, at least two perforated gibels 2 are projected. Although three insertion holes 2a are formed in the height direction in FIG. 1, the number of insertion holes 2a and the number of arrangements in the horizontal direction (horizontal direction) are arbitrary. FIG. 1 shows an example of the simplest structure.

  By arranging the perforated gibel 2 so as to face at least two horizontal directions, the penetrating rebar 3 is also arranged in at least two directions on the plane, and the two-way penetrating rebars 3 and 3 are the corners of the steel pipe column 1. Cross on the extension line. For this reason, the penetration reinforcing bars 3 and 3 of two directions are arranged with a level | step difference mutually. The section from the point where the two-way penetrating rebars 3 and 3 intersect to the tip functions as an anchor for the vertical shearing force from the flat slab 4, but the distance from the point of intersection of each penetrating rebar 3 to the tip is arbitrarily set Is done.

  Although not shown, for example, a perforated diver 2 is provided at the corner of the steel pipe column 1 so as to protrude in the diagonal direction of the steel pipe column 1 which is a square steel pipe, and at the intermediate portion of the surface (flange) of the steel pipe column 1 on its surface. If projecting vertically, the penetrating reinforcing bars 3 can be arranged in a direction parallel to the surface of the steel pipe column 1 and in a diagonal direction. Also in that case, the penetration reinforcing bars 3 and 3 in the two directions, the direction parallel to the surface of the steel pipe column 1 and the diagonal direction, are arranged so as not to interfere with each other in the height direction.

  In this case, the penetrating rebar 3 that faces the diagonal direction of the steel pipe column 1 is effective for cracking of the concrete in the flat slab 4 due to a horizontal shearing force or the like. Cracks in concrete tend to occur on a plane in a diagonal direction of a quadrangle 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. From this, if the penetrating rebar 3 facing the diagonal direction of the steel pipe column 1 is arranged so as to resist the tensile force that generates cracks in the diagonal direction of the quadrilateral or 45 degrees, the penetrating rebar 3 will be Resisting the force acts to suppress the occurrence of cracks.

  In FIG. 1- (a), the penetration reinforcement 3 which faces the diagonal direction of the steel pipe column 1 is shown with the dashed-two dotted line. The penetrating rebar 3 indicated by the two-dot chain line is arranged in a pair in the vertical direction in order to resist the positive and negative shearing forces. The pair of penetrating rebars 3 and 3 straddle between the two, and are connected to each other and restrained by lattice bars welded to both or hook bars having hooks at both ends.

  FIG. 2 shows a plurality of insertion holes 2a formed in the height direction in a plurality of rows in the horizontal direction, and perforated divels 2 arranged on each corner of the steel pipe column 1 and arranged in two directions. This is a case where the penetrating rebars 3 are arranged in a plurality of rows in the horizontal direction. 1 and 2 is welded to the surface of the steel pipe column 1 at the end face, for example, but the perforated divel 2 may penetrate the steel pipe column 1.

  In the case of FIG. 2, a plurality of penetrating rebars 3 arranged in a plurality of stages in the height direction and arranged in the horizontal direction share the vertical shearing force from the flat slab 4. Since the capacity increases, the transmission efficiency of the vertical shear force from the flat slab 4 to the steel pipe column 1 is improved. By increasing the number of penetration reinforcing bars 3, the transmission efficiency of the tensile force from the slab reinforcement 5 to the penetration reinforcing bars 3 is also improved.

  In the case of FIG. 2, a plurality of rows of through holes 2 a are arranged in the horizontal direction, so that the protruding width of the perforated gibel 2 from the steel pipe column 1 is increased. Can suppress the protrusion width to such an extent that it does not affect the workability on site.

  FIG. 3 shows a joint portion when a plurality of perforated gibels 2, specifically four, are combined to surround the steel pipe column 1. In this case, since a plurality of perforated gibels 2 are connected to each other and fixed to the outer periphery of the steel pipe column 1, a square steel pipe is suitable for the steel pipe column 1. It can be used for circular steel pipes by bending.

  The perforated diver 2 shown in FIG. 3 is divided in the length direction into a support portion 21 in which the insertion hole 2 a is formed and a fixing portion 22 fixed to the steel pipe column 1. When the steel pipe column 1 is a square steel pipe, the perforated gibber 2 has a length that is the size of the width of each surface (flange) of the steel pipe column 1 plus a length that can protrude from both sides. An insertion hole 2a is formed in a portion protruding in the width direction from the steel pipe column 1 when arranged around. The section of the perforated gibel 2 that overlaps the surface of the steel pipe column 1 becomes the fixed portion 22, and the portion that protrudes from the steel pipe column 1 becomes the support portion 21.

  For example, as shown in FIG. 4, a notch 2 b is formed on the side where two mutually intersecting perforated dowels 2, 2 orthogonal to each other are connected to each other, and both notches 2 b, 2 b face each other. In this state, the perforated dowels 2 and 2 that are engaged in two directions by being engaged with each other and are intersected are connected. Also in this case, the protruding width of the portion protruding from the steel pipe column 1 is arbitrarily set. The depth of the notch 2b is about half the width (height) of the perforated dowel 2. The perforated diver 2 is divided into a support portion 21 and a fixing portion 22 with the position of the notch 2b interposed therebetween.

  The bi-directional perforated divels 2 and 2 connected to each other maintain a state where they are fixed to the steel pipe column 1 by driving a wedge 6 between the surface of the steel pipe column 1. The wedge 6 is driven between the fixed portion 22 of the perforated diver 2 and the steel pipe column 1.

  When the wedge 6 is driven, the perforated gibber 2 located on the side facing the wedge 6 across the steel pipe column 1 is drawn toward the surface side of the steel pipe column 1, so By being pulled toward the steel tube column 1 by the wedge 6, the two-hole perforated gibels 2, 2 are fixed to the steel tube column 1. The perforated gibel 2 is maintained in a fixed state by frictional forces between both surfaces of the wedge 6 and the surface of the steel pipe column 1 and between the surface of the perforated gibel 2 on the steel pipe column 1 side.

  Also in the example of FIG. 3, a plurality of rows of insertion holes 2 a are arranged in the horizontal direction in the portion (support portion 21) that protrudes in the width direction from the steel pipe column 1, and the insertion holes 2 a closer to the end of the hole 2 By inclining with respect to the plate thickness direction, the penetrating rebar 3 can be arranged in a diagonal direction and a direction parallel to the surface of the steel pipe column 1. Although the penetration rebar 3 which faces the diagonal direction of the steel pipe pillar 1 is also shown in FIG. 3- (a) with the dashed-two dotted line, the penetration of the penetration reinforcing bar 3 shown with a two-dot chain line is arranged, and the concrete in the flat slab 4 is shown. Effective against cracks.

  FIG. 5 shows the direction of the perforated gibber 2 or the direction in which the insertion hole 2a intersects the slab bar 5 arranged in the flat slab 4 and the penetration bar 3 in the direction crossing the slab bar 5 The joint part is shown. In FIG. 5, the penetrating rebar 3 is arranged in the diagonal direction of the steel pipe column 1, so that it becomes an effective joint for concrete cracking in the flat slab 4.

  In FIG. 5, the perforated diver 2 is protruded in the diagonal direction of the steel pipe column 1 by welding or the like to the corner of the steel pipe column 1 with the bent or curved perforated perimeters 2 and 2 being overlapped. is doing. Here again, the perforated gibber 2 is divided into a support portion 21 in which the insertion hole 2 a is formed and a fixing portion 22 fixed to the steel pipe column 1 at the intermediate portion in the longitudinal direction. For example, it is inclined about 45 degrees. 5 may be joined to the steel pipe column 1 by a bolt at the fixing portion 22.

  In the example shown in FIGS. 1 to 5, the insertion hole 2 a is formed in the plate thickness direction of the perforated diver 2, and the penetrating rebar 3 is arranged in the plate thickness direction of the perforated divel 2, but the insertion hole 2 a is formed. The bar arrangement direction of the penetrating rebar 3 can be adjusted according to the direction. For example, in the example of FIGS. 1 to 3, the insertion hole 2 a is inclined by 45 degrees with respect to the plate thickness direction, and the perforated diver 2 is brought close to the corner portion of the steel pipe column 1 and joined. As shown in FIG. 5, the penetrating reinforcing bars 3 can be arranged so as to intersect the slab reinforcing bars 5. In that case, there is no need to bend the perforated gibber 2 shown in FIGS. 1 to 3 as shown in FIG.

  In the example of FIG. 5, if the insertion hole 2 a is formed in two directions of 45 degrees with respect to the plate thickness direction of the perforated diver 2, the penetrating rebar 3 is arranged parallel to the surface of the steel pipe column 1. You can also. In addition, if the insertion hole 2a is also formed in the plate thickness direction, the penetrating rebar 3 can be arranged in a direction parallel to the surface of the steel pipe column 1 and in a diagonal direction. validate.

(A) is a plan view showing a bar arrangement state of a joint portion when a perforated diver is joined to a corner portion of a steel pipe column in two directions and through-bars are arranged in a row, (b) is ( It is AA sectional view taken on the line of a). (A) is a plan view showing a bar arrangement state of a joint portion when a perforated dive is joined to a corner portion of a steel pipe column in two directions and through-bars are arranged in a plurality of rows, (b) It is BB sectional drawing of (a). (A) is the top view which showed the reinforcement arrangement | positioning state of the junction part at the time of enclosing a steel pipe pillar combining 4 perforated | drilled dowels, (b) is CC sectional view taken on the line of (a). It is the perspective view which showed the example of a combination of the perforated | grilled bell shown in FIG. (A) is a plan view showing the bar arrangement state of the joint when two perforated gibels 2 are combined and bonded to a steel pipe column and the penetration reinforcing bar is crossed with the slab bar, and (b) is It is the DD sectional view taken on the line of (a).

Explanation of symbols

1 ……… Steel pipe column 2 ……… Perforated gibber 2a …… Insertion hole 2b …… Notch 21 …… Supporting part 22 …… Fixing part 3 ……… Thinning reinforcing bar 4 ……… Flat slab 5 ……… Slab Muscle 51 …… Upper main muscle 52 …… Lower main muscle 6 ……… Wedge

Claims (3)

In the range of the thickness of the flat slab to be joined to the steel pipe column, the perforated divel is arranged in at least two directions with respect to the outer peripheral surface of the steel pipe column and maintained in a fixed state. The steel pipe column and the flat slab are connected to each other by penetrating through a reinforcing bar in the flat slab and combining a plurality of perforated gibels to surround the steel pipe column. 2. The steel pipe according to claim 1 , wherein the perforated gibber faces a direction intersecting a slab bar arranged in the flat slab, and the penetration reinforcing bar faces a direction intersecting the slab bar. Joint between column and flat slab. The said perforated perforation is arrange | positioned so that it may be settled between the upper-end main reinforcement and lower-end main reinforcement which are slab reinforcement arranged in the said flat slab, The Claim 1 or Claim 2 characterized by the above-mentioned. Joint between steel pipe column and flat slab.

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