JP5767032B2 - Steel column joint anchor member - Google Patents

Description

  The present invention is directed to an exposed steel column joint structure for a reinforced concrete frame, can suppress the occurrence of bending deformation, can also prevent local crushing of the concrete of the reinforced concrete frame, and further, the concrete cross section of the reinforced concrete frame It is related with the anchor member for steel column joining which does not produce the defect | deletion of and can ensure sufficient tensile strength.

  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. The following problems are known in the exposed-type steel column joint structure.

  Of the exposed joint structure, the problem will be described by taking a pin-type joint structure as an example. The pin-type joining structure is a joining method aiming to suppress the moment transmission between the RC structure and the steel column as much as possible while ensuring the necessary shear strength and necessary tensile strength.

  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.

  Such problems are not limited to the pin type, but more or less, the exposed steel column joint structure in general.

  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 general structure of the exposed type steel column connection including a pin type, by providing the steel pipe for reinforcement around the anchor bolt, the shear strength of the anchor bolt itself is increased, Bending deformation can be suppressed.

  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, and is capable of suppressing the occurrence of bending deformation for an exposed steel column-joint structure with respect to the RC steel structure. An object of the present invention is to provide an anchor member for joining steel columns that can prevent local crushing and that can ensure sufficient tensile strength without causing a loss of the concrete section of the RC structure. And

An anchor member for joining steel columns according to the present invention includes a steel bar in which a male screw part fastened to a lower end part of a steel column is formed at an upper end part, and a shaft body part below the male screw part is embedded in a reinforced concrete frame, and the steel bar A rectangular shear plate material in which the side edges of the shaft body part are joined to each other face to face with each other across the shaft body part, and inserted into the steel bar. And a constraining plate material that surrounds the steel bar and is joined to the upper edge of the shear plate material on the male screw portion side, and connects the shear plate materials to each other.

  The steel bar is characterized in that a fixing portion for fixing the shaft body portion to the reinforced concrete frame is formed at a lower end portion thereof.

  The shear plate material has an extending portion extending outward in the axial length direction of the shaft body portion, and the extending portions are joined to each other.

  As the steel bar, a deformed reinforcing bar is used, and a pipe material inserted through the deformed reinforcing bar and integrally joined thereto is used. Instead of joining the shear plate to the shaft body portion, the steel plate is joined to the pipe material. It is characterized by doing.

  The shear plate material is formed with a plate fixing portion for fixing it to the reinforced concrete frame.

  The shear plate material is formed with a through-hole through which the concrete constituting the reinforced concrete frame flows.

In the anchor member for steel column connection according to the present invention, it is possible to suppress the occurrence of bending deformation for the exposed steel column connection structure with respect to the RC structure, and to locally collapse the concrete of the RC structure. In addition, it is possible to ensure a sufficient tensile strength without causing defects in the concrete cross section of the RC structure. Specifically, since the restraint plate material is not joined to the steel bar, the tensile force generated in the steel bar can be directly transmitted to the shear plate material. When an external force is applied to the steel column, the anchor member for connecting the steel column is transferred between the steel column and the RC structure by the shear force applied to the steel bar being stably transmitted to the RC structure by the shear plate material. It can sufficiently resist the acting shear force. The concrete of the RC structure can be constrained by the constraining plate material and the shearing plate material joined to each other, so that local collapse occurring in the concrete around the steel bar can be prevented. Furthermore, by preventing crushing, horizontal displacement and bending deformation that occur in the steel bar can be suppressed.

It is a perspective view which shows 1st Embodiment of the anchor member for steel frame joining which concerns on this invention. It is a front view which shows a mode that the anchor member for steel column joining of FIG. 1 was installed in the junction part of a steel column and RC frame. When a brace is attached to a steel column, it is a schematic plan view which shows the direction by which the shear plate material of the anchor member for steel column joining of FIG. 1 is arrange | positioned. It is explanatory drawing for demonstrating the state of the shearing force, horizontal displacement, and crushing in an exposed type steel-column connection structure. It is a perspective view which shows the modification of the anchor member for steel column joining of FIG. It is a perspective view which shows the other modification of the anchor member for steel column joining of FIG. It is a perspective view which shows 2nd Embodiment of the anchor member for steel column joining which concerns on this invention. It is a disassembled perspective view which shows the modification of the anchor member for steel column joining of FIG. It is a disassembled perspective view which shows 3rd Embodiment of the anchor member for steel column joining which concerns on this invention.

  Hereinafter, preferred embodiments of an anchor member for joining steel columns according to the present invention will be described in detail with reference to the accompanying drawings. 1 to 3 show a steel column joining anchor member 1 according to a first embodiment.

The steel column joining anchor member 1 is mainly composed of a steel bar 2 such as a straight round steel, a plurality of square and flat shear plate members 3, and a ring and flat constraining plate member 4. The shape of the plate material 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 the insertion hole of the base plate 6 joined to the lower end portion of the steel column 5, and the nut 7 is screwed, 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 steel structure 8 by embedding the shaft body part 2b below the male screw part 2a in the RC steel structure 8 such as an RC structure foundation or an RC pillar.

  FIG. 2 shows a pin-type exposed steel column joint structure in which a steel bar 2 is fastened to a central portion (column core) of a base plate 6 of a hollow cylindrical steel column 5. Of course, other types of exposed steel column connection structures may be used in which the steel bar 2 is fastened to the peripheral side of the base plate 6.

  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 structure 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. It is preferable that the constraining plate material 4 is not joined to the steel bar 2 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. 2, when the shaft body portion 2 b including the shear plate material 3 is embedded in the RC forging body 8, the constraining plate material 4 has the RC forging body 8 in order to hold down the upper surface 8 a of the RC forging body 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 steel structure 8, and the restraint plate material 4 of the upper edge 3b of the shear plate material 3 is the RC steel structure. 8 is embedded at a position so as to cover and contact the upper surface 8a of 8 from above.

  The anchor member 1 for fixing the steel column according to the first embodiment is further formed with a fixing portion for fixing the shaft body portion 2b to the RC forging body 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.

  In addition, the anchor member 1 for steel column connection according to the first embodiment is formed with a plate fixing portion for fixing the shear plate material 3 to the RC structure 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 bolts 11, bolts and nuts that penetrate and fasten the shear plate material 3 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.

  The operation of the steel column joining anchor member 1 according to the first embodiment will be described. As for the anchor member 1 for steel column connection, the shaft body part 2b of the steel bar 2 including the shear plate material 3 is embedded in the RC structure 8 such as the RC foundation or the RC column, and the male thread part 2a of the steel bar 2 is the RC structure. The upper plate 8 protrudes upward from the upper surface 8 a of the housing 8, and the restraint plate material 4 is brought into contact with the upper surface 8 a of the RC housing 8 so as to surround the steel bar 2.

  The male thread portion 2a of the steel bar 2 of the anchor member 1 for steel column connection is fastened with a nut 7 to the base plate 6 of the steel column 5 built from above. A grout material G is filled between the base plate 6 and the RC steel structure upper surface 8a as necessary.

  When an external force is applied to the steel column 5, the steel column joining anchor member 1 stably transmits the shearing force applied to the steel bar 2 to the RC steel structure 8 by the shear plate material 3, as shown in FIG. 4. It is possible to sufficiently resist the shearing force Q acting between the steel column 5 and the RC structure 8 as shown. 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.

  In addition, since the RC plate upper 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, local portions 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 junction structure.

  In addition, since the arrangement of the shear plate material 3 is a radial arrangement centered on the steel bar 2, the concrete of the RC structure 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 explained above, in the anchor member 1 for steel column connection according to the first embodiment, the exposed steel column connection structure for the RC structure 8 such as the RC foundation or RC column is bent. It is possible to suppress the occurrence of deformation, to prevent local crushing of the concrete or the like of the RC structure 8 and to prevent the RC cross section 8 from being damaged, and to provide sufficient tensile strength. Can be secured.

  Further, in the first 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 structure 8 and the steel bar 2 and the shear plate material are used. 3 can be enhanced, and the tensile performance can be improved.

  FIG. 5 shows a modification of the first embodiment. In this modification, the plate fixing unit is omitted.

  FIG. 6 shows another modification. In this modified example, in order to improve the filling property of the concrete for constructing the RC structure 8 in the shear plate material 3 of the anchor member 1 for steel column connection shown in FIG. A hole 16 is formed.

  Since concrete circulates around the shear plate material 3 through the through-hole 16, the fixing performance of the anchor member 1 for steel column connection 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 first embodiment. Even in these modified examples, it is needless to say that the same effects as those of the first embodiment can be obtained.

  FIG. 7 shows a steel column joining anchor member 1 according to the second embodiment. In the second embodiment, the fixing portion formed at the lower end portion of the steel bar 2 is omitted. In order to expand the plate surface of the shear plate material 3 of the first embodiment, each shear plate material 3 of the second embodiment extends outwardly of the shaft body portion 2b in the axial length direction of the shaft body portion 2b. It has the extension part 3d. And these extension parts 3d are mutually joined and the shear plate material 3 is integrated.

  Specifically, in the shear plate material 3 used in the second embodiment, the side edge facing the shaft body portion 2b is formed longer than the shaft body portion 2b, and the shaft body portion 2b is formed above the side edge. A notch 3e is formed to be fitted into the. 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 the second embodiment, the plate area of the shear plate material 3 fixed to the RC structure 8 can be expanded, and the bending deformation suppressing action and the cited yield strength can be increased.

  FIG. 8 shows a modification of the anchor member 1 for steel column connection according to the second embodiment. 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. Similar to the second embodiment, 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 abutted and joined to the expanded shear plate material 3x. In this modification, the number of parts and the number of joints can be reduced. Even in such a modification, it is needless to say that the same effects as those of the second embodiment can be obtained.

  FIG. 9 shows a steel column joining anchor member 1 according to the third embodiment. The third embodiment is a case where a deformed 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 third embodiment, it is a matter of course that the same operational effects as 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, generally, two anchor members 1 for joining steel columns are provided across a web and fastened to a 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 Steel column joining 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 3d Extension part 4 Restraint plate material 5 Steel column 8 Reinforced concrete frame 10 Nut with fixing plate 11 Stud bolt 16 Through hole 18 Pipe material

Claims (6)

A male screw part fastened to the lower end part of the steel column is formed at the upper end part, and the shaft body part below the male screw part is embedded in the reinforced concrete frame, and the shaft body part of the steel bar is at least from the side. A quadrangular shear plate material in which two side edges are joined face to face with each other with the shaft body part interposed therebetween, and the steel plate is inserted into and surrounds the steel bar, and these shear plate materials An anchor member for joining steel columns, comprising: a restraint plate material joined to the upper edge of the male screw portion side and connecting the shear plate materials to each other.   The steel bar joint anchor member according to claim 1, wherein a fixing portion for fixing the shaft body portion to the reinforced concrete frame is formed at a lower end portion of the steel bar.   The shear plate material has an extending portion that extends outward in the axial direction of the shaft body portion, and the extending portions are joined to each other. The anchor member for steel column joining as described in 2.   As the steel bar, a deformed reinforcing bar is used, and a pipe material inserted through the deformed reinforcing bar and integrally joined thereto is used. Instead of joining the shear plate to the shaft body portion, the steel plate is joined to the pipe material. The steel column joining anchor member according to any one of claims 1 to 3, wherein:   The steel plate column anchoring member according to any one of claims 1 to 4, wherein a plate fixing portion for fixing the shear plate material to the reinforced concrete frame is formed on the shear plate material.   The steel plate joint anchor member according to any one of claims 1 to 5, wherein the shear plate material is formed with a through-hole through which the concrete constituting the reinforced concrete frame flows.

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