JP5701158B2 - Exposed steel column joint structure of pin joint type - Google Patents

Description

  The present invention can suppress the occurrence of bending deformation, can also prevent local crushing of the concrete of the reinforced concrete frame, etc., and does not cause the loss of the concrete section of the reinforced concrete frame, sufficient tensile strength The present invention relates to an exposed steel column joint structure of a pin joint type capable of ensuring the above.

  In buildings using steel columns, the lower end of the steel column is exposed on the RC structure such as the RC foundation, as the connection structure between the steel column and the RC foundation, or the connection structure of the steel column and the RC column. An exposed-type joining structure that joins together is known.

  Of the exposed joint structures, the pin-type joint structure is a joint method that aims to minimize the moment transmission between the RC structure and the steel column while ensuring the necessary shear strength and necessary tensile strength. is there.

  Usually, in the joining structure by the pin form, the installation position of the anchor bolt as an anchor member used for joining the steel column and the RC structure is set as close as possible to the base plate center of the steel column. By setting to such an installation position, the bending moment borne by the anchor bolt is reduced, and the anchor bolt can exert a large resistance against the shearing force and tensile force acting on the steel column.

  In the exposed steel column connection structure, when a large shearing force acts on the steel column, stress concentrates near the upper surface of the RC structure, which is a joint between the steel column (base plate) and the RC structure.

  In joints where stress concentration occurs, especially in the pin type joint, the anchor bolts are joined near the center of the base plate as described above, whereas the reinforcing bars inside the RC structure are placed around the base plate. Therefore, the area around the anchor bolt is in an unreinforced state where there is no reinforcing bar. Since the area around the anchor bolt is not properly reinforced, the concrete of the RC structure is locally crushed through the anchor bolt that bears the shearing force, and accordingly, the anchor bolt itself is bent. Deformation would occur.

  If this situation is reached, the horizontal displacement of the steel column will increase, and the load associated with the bending moment will be applied to the anchor bolts. Consequently, the pin-type joining performance will not be able to function sufficiently. There was a problem.

  As a technique that can cope with such a problem, Patent Document 1 is known. The “anchor bolt with reinforcing pipe” of Patent Document 1 is accompanied by the vertical movement that has been regarded as a blind spot in the conventional construction method due to the increased strength of the shearing force and bending moment by the steel pipe for reinforcement around the anchor bolt. For the purpose of providing an anchor bolt with a reinforcing pipe having an effect that the earthquake resistance can be remarkably increased, a reinforcing steel pipe having a strength is incorporated in the outer peripheral portion of the anchor bolt.

Japanese Utility Model Publication No. 6-67544 Japanese Patent Publication No. 8-1079

  Although the said patent document 1 does not respond | correspond to the pin-type exposed steel column connection structure, providing the steel pipe for reinforcement around an anchor bolt increases the shear strength of anchor bolt itself, and suppresses bending deformation. obtain.

  However, the disclosed configuration of Patent Document 1 cannot solve the problem that the concrete of the RC structure is locally collapsed via the anchor bolt. Furthermore, because the structure is provided with a steel tube for reinforcement that is larger than the outer diameter of the anchor bolt, the cross section of the concrete that opposes the anchoring portion (side J-shaped portion) at the lower end of the anchor bolt (the horizontal effective projected area against so-called cone-shaped fracture) It is feared that the tensile strength is reduced.

  As an RC structure, an exposed joint structure is known in Patent Document 2 in which a steel column is joined in a pin form to an RC pillar that has been raised to a height at which the bending moment becomes “0”. Even with such a structural format, the same problems as described above occur. In the case of Patent Document 2, since the cross section of the RC column is smaller than the basic cross section, these problems may occur remarkably.

  The present invention was devised in view of the above-described conventional problems, can suppress the occurrence of bending deformation, can also prevent local crushing of concrete of the RC structure, and further, the RC structure. It is an object of the present invention to provide an exposed steel column joint structure of a pin joint type capable of ensuring a sufficient tensile strength without causing defects in the concrete section.

  The exposed steel column joint structure of the pin joint type according to the present invention is an exposed steel column joint structure of the pin joint type in which the center part of the lower end of the steel column is rotatably joined to the upper surface of the reinforced concrete frame. A threaded part is formed on the upper end part, and a steel bar having a shaft body part formed below the male thread part, and the shaft body part of the steel bar, at least two from the side, and the side edges thereof are A shear plate material joined to face each other across the shaft body portion, and a restraint plate material joined to the upper edge of the male screw portion of these shear plate materials and interconnecting these shear plate materials When the shaft member including the shear plate material is embedded in the reinforced concrete frame so that the restraint plate material is in contact with the upper surface of the reinforced concrete frame from above using an anchor member. In, the male screw portion of the bars projecting from the reinforced concrete skeleton top, characterized in that fastened to the central portion of the lower end of the steel columns.

  A pipe material that is inserted through the steel bar and integrally joined thereto is used, and the shear plate is joined to the pipe material instead of joining to the shaft body portion of the steel bar.

  The reinforced concrete frame is a reinforced concrete column built up from a foundation.

  A gap is set between the upper surface of the reinforced concrete frame with which the restraint plate material is abutted and the lower end of the steel column.

  In the gap, a washer is provided so as to be sandwiched between the restraint plate material and the lower end portion of the steel column.

  The shear plate material is provided with a temporary fixing member for temporarily fixing the steel column to the reinforced concrete frame side.

  In the exposed steel column joint structure of the pin joint type according to the present invention, it is possible to suppress the occurrence of bending deformation, to prevent local crushing of the concrete of the RC structure, etc. It is possible to ensure a sufficient tensile strength without causing defects in the concrete section of the frame.

1 is a partially broken front view showing a preferred embodiment of an exposed steel column joint structure of a pin joint type according to the present invention. It is a perspective view which shows the anchor member applied to the exposed type steel column joint structure of the pin joint type of FIG. It is a schematic plan view which shows the direction where the shear plate material of the anchor member of FIG. 2 is arrange | positioned when a brace is attached to a steel column. It is explanatory drawing for demonstrating the state of the shearing force, horizontal displacement, and crushing in the pin-joint-type exposed steel-column connection structure. It is a perspective view which shows the modification of the anchor member of FIG. It is explanatory drawing explaining the temporary attachment construction procedure of the steel column by the anchor member shown in FIG. It is a perspective view which shows the other modification of the anchor member of FIG. It is a perspective view which shows the other modification of the anchor member of FIG. It is a perspective view which shows the other modification of the anchor member of FIG. It is a disassembled perspective view which shows the modification of the anchor member of FIG. It is a disassembled perspective view which shows the further another modification of the anchor member of FIG.

  Hereinafter, a preferred embodiment of an exposed steel column joint structure of a pin joint type according to the present invention will be described in detail with reference to the accompanying drawings. As shown in FIG. 1, the exposed steel column joint structure of the pin joint type according to the present embodiment is an example in which a hollow cylindrical steel column 5 is joined on an RC pillar 8 as an RC steel structure. Has been.

  The RC column 8 is built up to the middle height position of the layer where the RC pillar 8 is raised on the foundation and the moment is “0” in the rigid frame structure fixed at the lower end. The steel column 5 is installed on the RC column 8 having a moment of “0”, and is joined in a pin joint form.

  In terms of structural mechanics, the pin joining type is a joining method in which the steel column 5 can rotate with respect to the RC column 8, and in this case, only the central portion of the base plate 6 joined to the lower end portion of the steel column 5 and the vicinity thereof. Is bonded to the upper surface 8a of the RC pillar 8.

  The steel column 5 is joined to the RC column 8 using a single anchor member 1. The anchor member 1 is mainly composed of a steel bar 2 such as a straight round steel, a plurality of rectangular flat plate shear plates 3 and a ring-shaped flat constraining plate material 4. The shape of these plate materials 3 and 4 is an example, and other shapes may be used. These plate materials 3 and 4 are formed of a metal material such as a steel plate.

  The steel bar 2 is used upright and down, and a male screw portion 2a is formed at the upper end portion. The male screw portion 2 a is inserted into an insertion hole formed in the base plate 6 at the lower end portion of the steel column 5, and a nut 7 is screwed thereto, whereby the steel bar 2 is fastened to the steel column 5. The steel bar 2 protrudes from the upper surface 8a of the RC pillar 8 when the shaft body part 2b below the male screw part 2a is embedded in the RC pillar 8.

  The shear plate material 3 is joined to the shaft body portion 2b below the male screw portion 2a. The shear plate material 3 is joined in pairs. The shear plate material 3 is joined to the shaft body portion 2b from the side of the shaft body portion 2b so that the side edges 3a facing the shaft body portion 2b face each other with the shaft body portion 2b interposed therebetween. A plurality of sets of shear plate materials 3 may be joined, and in the illustrated example, two sets are joined. When a plurality of sets are joined, these shear plate members 3 are joined to the steel bar 2 in a radial arrangement around the shaft body portion 2b.

  In particular, as shown in FIG. 3, when the brace 9 is attached to the steel column 5, in order to effectively bear the shear force acting on the steel column 5 along the attachment direction of the brace 9 with the shear plate material 3, Among the shear plate members 3 to be joined to the steel bar 2, one set of two shear plate members 3 is positioned so as to be orthogonal to the brace 9 and embedded in the RC column 8.

  The shear plate material 3 is joined to the shaft body portion 2b by welding. Of course, other welding methods such as gas pressure welding may be used.

  The ring-shaped constraining plate material 4 is inserted into the steel bar 2 from the male screw portion 2a side, and joined to the upper edge 3b of the plurality of shear plate materials 3 on the male screw portion side. The restraint plate material 4 connects the shear plate materials 3 to each other. That is, the restraint plate material 4 connects the plurality of shear plate materials 3 along the periphery of the steel bar 2. The outer dimension of the restraint plate material 4 is preferably set to be smaller than the outer diameter of the steel column 5 and slightly smaller than the length of the upper edge 3 b of the shear plate material 3. The hole diameter of the restraining plate material 4 is formed slightly larger than the outer diameter of the steel bar 2 so that it can be inserted into the steel bar 2.

  The restraint plate material 4 is joined to the shear plate material 3 by welding joint. Of course, other welding methods such as gas pressure welding may be used. The constraining plate material 4 may be joined to the steel bar 2, but it is preferable not to join it because the tensile force generated in the steel bar 2 is directly transmitted to the shearing plate material 3 and a fixing portion described later.

  As shown in FIG. 1, when the shaft body portion 2 b including the shear plate material 3 is embedded in the RC column 8, the constraining plate member 4 has the RC column 8 in order to hold down the upper surface 8 a of the RC column 8. It is positioned at a position where it comes into contact with the upper surface 8a from above. Specifically, the shaft body portion 2b of the steel bar 2 has the upper edge 3b of the shear plate material 3 flush with the upper surface 8a of the RC column 8, and the restraint plate material 4 of the upper edge 3b of the shear plate material is the RC column. 8 is embedded at a position so as to cover and contact the upper surface 8a of 8 from above.

  The anchor member 1 according to the present embodiment further includes a fixing portion for fixing the shaft body portion 2b to the RC pillar 8. The fixing portion is formed at the lower end of the steel bar 2. In the illustrated example, a nut 10 with a fixing plate is screwed into a lower male screw portion 2 c formed at the lower end portion of the steel bar 2. The form of the fixing portion is not limited to this, and various known fixing structures such as a hook portion in which the steel bar 2 is bent back can be employed.

  Further, the anchor member 1 according to the present embodiment is formed with a plate fixing portion for fixing the shear plate material 3 to the RC pillar 8. In the illustrated example, the plate fixing portion is constituted by a plurality of stat bolts 11 erected from the front and back surfaces of the shear plate material 3. Instead of the stud bolt 11, a bolt and nut that penetrates and fastens the shear plate material may be used. As the form of the plate fixing unit, various well-known fixing structures such as a concavo-convex form can be adopted.

  A gap S is set between the upper surface 8a of the RC column 8 joined by the anchor member 1 and the base plate 6 of the steel column 5 by the constraining plate material 4 abutting against the RC column upper surface 8a. Due to the gap S, the rotational performance of the steel column 5 with respect to the RC column 8 is improved.

  In the present embodiment, a steel ring-shaped washer 12 is provided in the gap S so as to overlap the restraint plate member 4 and be sandwiched between the restraint plate member 4 and the base plate 6. The outer diameter dimension of the washer 12 is set to be smaller than that of the constraining plate material 4 so that the upper surface 8a of the RC pillar 8 is not damaged by the washer 12. By providing the washer 12, the rotational performance of the steel column 5 is further improved.

  The operation of the exposed steel column joint structure of the pin joint type according to this embodiment will be described. The anchor member 1 includes a shaft body portion 2b of a steel bar 2 including a shear plate material 3 embedded in an RC column 8, and a male screw portion 2a of the steel bar 2 protrudes above an upper surface 8a of the RC column 8 and is restrained. The plate material 4 is brought into contact with the upper surface 8a of the RC pillar 8 so as to surround the steel bar 2. A washer 12 is attached to the male screw portion 2a exposed on the RC column top surface 8a so as to overlap the restraint plate material 4.

  Further, the male threaded portion 2a of the steel bar 2 of the anchor member 1 is fastened with a nut 7 to approximately the center portion or the periphery of the base plate 6 of the steel column 5 built from above. Thereby, the exposed steel column joining structure of the pin joint type which joined the center part of the steel column 5 to the RC pillar 8 with the anchor member 1 through the clearance S and the washer 12 is obtained.

  When an external force is applied to the steel column 5, the steel column 5 exhibits a smooth rotating action on the RC column 8 due to the gap S and the washer 12. At this time, the anchor member 1 has the shear force applied to the steel bar 2 stably transmitted to the RC column 8 by the shear plate material 3, so that the steel column 5 and the RC column 8 as shown in FIG. It is possible to sufficiently resist the shearing force Q acting between them. In particular, when the brace 9 is attached to the steel column 5, the shear plate material 3 is arranged in a direction orthogonal to the attaching direction of the brace 9, so that it can effectively resist the shearing force.

  Further, the RC plate top surface 8a and the concrete in the vicinity thereof can be constrained by the constraining plate material 4 and the shear plate material 3 joined to each other, so that local parts generated in the concrete around the steel bar 2 as shown in FIG. Crushing C can be prevented. Furthermore, by preventing crushing, horizontal displacement X and bending deformation that occur in the steel bar 2 can be suppressed.

  By the above, it can suppress reliably that bending deformation arises in the junction part of the steel column 5 and RC structure 8 in the exposed type steel column joining structure of a pin joining type.

  In addition, since the arrangement of the shear plate material 3 is a radial arrangement centering on the steel bar 2, the concrete of the RC column 8 that opposes the fixing portion (the nut 10 with the fixing plate) formed at the lower end of the steel bar 2. Of the cross section (horizontal effective projected area against so-called cone-like fracture) can be minimized, and high tensile strength can be ensured.

  As described above, in the exposed steel column joint structure of the pin joint type according to the present embodiment, the occurrence of bending deformation can be suppressed and the local collapse of the RC pillar 8 such as concrete can be performed. In addition, it is possible to ensure a sufficient tensile strength without causing the concrete cross section of the RC column 8 to be lost.

  Furthermore, in this embodiment, since the fixing portion is formed on the steel bar 2 and the plate fixing portion (stud bolt 11) is formed on the shear plate material 3, the concrete of the RC pillar 8 and the steel bar 2 and the shear plate material 3 are formed. Can be enhanced, and the tensile performance can be improved.

  In the above description, the RC pillar 8 has been described as an example of the RC structure, but it is a matter of course that even an RC foundation can be similarly applied and configured. When the cross section of the RC structure is large, various measures can be adopted. However, in this embodiment, the RC structure can be configured only by embedding the anchor member 1, so that the cross section is similar to the cross section of the RC pillar. It can function effectively when it is small.

  5 and 6 show a modification of the above embodiment. This modification is an exposed steel column joint structure of a pin joint type having a function of temporarily fixing a steel column 5 that is a pin joint type and is difficult to be stably self-supporting by joining by a single anchor member 1. As shown in FIG. 5, a long nut 13 is joined to the shear plate member 3 as a temporary fixing member on the opposite side edge 3c that is not joined to the shaft body portion 2b.

  The long nut 13 is provided on the shear plate material 3 so that its length direction is along the height direction of the steel column 5. Further, the upper end of the long nut 13 is exposed to the RC column upper surface 8a so that the screw member 14 can be screwed. In the illustrated example, it is provided on all four shear plate materials 3, but may not be provided on all shear plate materials 3.

  FIG. 6 sequentially shows the construction state. An insertion hole for temporary fixing is formed through the base plate 6 in accordance with the position of the long nut 13. As shown in FIG. 6 (A), a screw member 14 is screwed into each long nut 13 so as to rise from the RC column 8, and the steel column 5 is built from above.

  While inserting the screw member 14 into the insertion hole of the base plate 6, the steel column 5 is lowered and installed on the RC column upper surface 8 a, and as shown in FIG. 6B, the nut 15 is attached to the screw member 14 from above the base plate 6. Conclude. Thereby, the steel column 5 can be temporarily fixed to the RC column 8 side.

  When various peripheral operations relating to the construction method of the steel column 5 are completed by connecting beams between the steel columns 5 and the like, as shown in FIG. Remove. Since the shear plate material 3 is provided with a temporary fixing member (long nut 13), the steel column 5 being built can be stably temporarily fixed by the anchor member 1 even in the case of a rotatable pin joint type. And workability can be improved.

  FIG. 7 shows a modification of the anchor member 1. In this modification, the plate fixing unit is omitted.

  FIG. 8 shows another modification. In this modification, through holes 16 penetrating toward the front and back surfaces are formed in the shear plate material 3 of the anchor member 1 shown in FIG. Has been.

  Since the concrete flows around the shear plate material 3 through the through holes 16, the fixing performance of the anchor member 1 can be improved. Needless to say, the through hole 16 may be formed in the shear plate material 3 having the plate fixing portion of the above embodiment. Even in these modifications, it is a matter of course that the same operational effects as those of the above-described embodiment can be obtained.

  FIG. 9 shows still another anchor member 1. In this modification, the fixing portion formed at the lower end portion of the steel bar 2 is omitted. Each shear plate material 3 of this modification has an extending portion 3d extending outward in the axial direction of the shaft body portion 2b in order to expand the plate surface of the shear plate material 3. . And these extension parts 3d are mutually joined and the shear plate material 3 is integrated.

  Specifically, the shear plate material 3 used in this modified example has a side edge facing the shaft body portion 2b that is longer than the shaft body portion 2b. A cutout portion 3e to be fitted is formed. Each shear plate material 3 is joined to the shaft body portion 2b at the notch portion 3e, and the side edge lower portions 3f below the notch portion 3e are joined to each other. The joining method is the same as described above.

  In this modification, the plate area of the shear plate material 3 fixed to the RC pillar 8 can be expanded, and the bending deformation suppressing action and the cited proof strength can be increased.

  FIG. 10 shows a modification of the anchor member 1 shown in FIG. In this modified example, one set of two shear plate members 3 is integrated based on joining of the extending portions 3d of the shear plate member 3 to each other. That is, the slit 17 which can fit the shaft body portion 2b is formed in the expanded shear plate material 3x having the size of two sheets.

  The expanded shear plate material 3x is joined to the shaft body portion 2b by the slit 17. The other shear plate material 3 is joined to the shaft body portion 2b by the notch portion 3e and the side edge lower portion 3f is butted to the expanded shear plate material 3x in the same manner as shown in FIG. . In this modification, the number of parts and the number of joints can be reduced. Even in such a modification, it is a matter of course that the same operational effects as those of the above-described embodiment can be obtained.

  FIG. 11 shows still another modified example of the anchor member 1. This modification is a case where a deformed reinforcing bar is used as the steel bar 2. In the case of a deformed reinforcing bar, a pipe material 18 is used to appropriately join the shear plate material 3.

  The pipe member 18 has a deformed reinforcing bar corresponding to the steel bar 2 inserted in the hollow inside thereof, and is integrally joined thereto. For joining the pipe material 18 and the deformed reinforcing bar, for example, a nut is used, or a joining method similar to the above is adopted. The shear plate material 3 is joined to the peripheral side surface of the pipe material 18. Needless to say, the pipe material 18 may be used not only for deformed reinforcing bars but also for round steel bars. Even in such a modification, it is needless to say that the same effects as those of the above-described embodiment can be obtained.

  In any of the above embodiments, the case where the steel column 5 has a hollow cylindrical shape has been described. However, an H-section steel may be used. In this case, two anchor members 1 are generally provided on the web so as to sandwich the anchor member 1 and fastened to the base plate 6 respectively.

  In any of the above embodiments, the restraint plate material 4 has been described as having a ring shape surrounding the steel bar 2, but a plurality of pieces can be used as long as the adjacent shear plate material 3 is surrounded around the steel bar 2. May be formed by annularly joining.

DESCRIPTION OF SYMBOLS 1 Anchor member 2 Steel bar 2a Male thread part 2b Shaft body part 3 Shear plate material 3a Side edge 3b Male screw part side upper edge 4 Restraint plate material 5 Steel column 8 Reinforced concrete pillar 8a Upper surface 12 Washer 13 Long nut S Gap

Claims (6)

In the exposed steel column joint structure of the pin joint type in which the central part of the lower end of the steel column is rotatably joined to the upper surface of the reinforced concrete frame,
A steel bar having a male thread formed at the upper end and a shaft body formed below the male thread, and a pair of at least two from the side of the shaft body of the steel bar. Are joined to each other across the shaft body portion, and a shear plate material joined to the upper edge of the male screw portion of the shear plate material, and a restraint plate material that connects the shear plate materials to each other. Using the anchor member provided,
The shaft body portion including the shear plate material is embedded in the reinforced concrete frame so that the restraint plate material contacts the upper surface of the reinforced concrete frame from above,
An exposed steel column joint structure of a pin joint type, wherein the male thread portion of the steel bar protruding from the upper surface of the reinforced concrete frame is fastened to a central portion of a lower end portion of the steel column.   2. A pipe member that is inserted into the steel bar and integrally joined thereto is used, and the shear plate is joined to the pipe material instead of joining to the shaft body portion of the steel bar. Exposed type steel column joint structure of the pin joint type described in 1.   3. The exposed steel column joint structure of the pin joint type according to claim 1, wherein the reinforced concrete frame is a reinforced concrete column built up from a foundation.   The pin according to any one of claims 1 to 3, wherein a gap is set between an upper surface of the reinforced concrete frame with which the restraint plate material is abutted and a lower end portion of the steel column. Exposed type steel column joint structure of joint type.   The exposed steel column joint structure of the pin joint type according to claim 4, wherein a washer is provided in the gap between the restraint plate member and a lower end portion of the steel pillar.   The pin type exposed type according to any one of claims 1 to 5, wherein the shear plate material is provided with a temporary fixing member for temporarily fixing the steel column to the reinforced concrete frame side. Steel column connection structure.

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