JP5483525B2 - Seismic wall - Google Patents

Description

  The present invention mainly reduces the pull-out force acting on a frame such as a foundation beam to which a lower end portion of a seismic wall is fixed or a fixture such as an anchor bolt fixed to the frame for fixing as much as possible. This is related to a seismic wall.

  Pin brace structure and ramen structure are the main types of steel structure. The pin brace structure is a structure that counteracts the horizontal external force that acts in the event of an earthquake, etc. by connecting pins and beams with a relatively small cross section and pinning, placing a seismic wall or brace at the required location of the frame, It is a relatively rigid housing. In addition, the rigid frame structure is a structure in which main columns and beams are rigidly connected, and the horizontal external force acting in the event of an earthquake, etc. is resisted by the bending strength of the beam-column joints. This ramen structure has a merit that a large space can be easily formed because the cross section of a column or beam is larger than that of a pin brace structure, but a seismic wall or brace is unnecessary.

  The three-story and four-story medium-rise steel frame structure has excellent deformation performance and retained horizontal strength against large earthquakes, but tends to increase the interlayer deformation angle in the lower part during a middle earthquake. Furthermore, in recent years, there has been a tendency that higher earthquake resistance performance is desired for buildings, and in order to obtain a higher earthquake resistance grade in the quality assurance method, it is necessary to suppress the interlayer deformation angle against larger earthquake forces.

  In the process of structural calculation of the target building, if the interlayer deformation angle generated in the building is larger than the allowable interlayer deformation angle, it is necessary to increase the rigidity of the lower part of the building mainly to make the interlayer deformation angle below the allowable value. There is.

  As a method for increasing the rigidity of such a middle-layer steel frame structure, there are a method for improving the cross-sectional performance of the columns and a method for increasing the number of columns to be arranged. For industrialized houses with standardized members, the latter method, which can be handled with pillar members that have already been established, is often selected. However, when the number of columns is increased in a ramen structure, the foundation beam is accompanied accordingly. The use amount of structural members such as steel beams and steel beams increases, resulting in an increase in cost.

  Therefore, as a method to suppress the deformation of the building during an earthquake without increasing the number of columns that make up the ramen structure, a seismic wall constructed by incorporating diagonal materials between a pair of columns is added to the ramen structure. (For example, Patent Document 1). Such a seismic wall is relatively easy to deal with when an existing building is subjected to seismic reinforcement.

  In the above-mentioned seismic wall, when a horizontal reciprocating force such as an earthquake acts to cause a relative displacement between the upper beam and the foundation beam, one of a pair of studs fixed to the upper beam and the foundation beam. Compressive force acts alternately on the other side, and tensile force acts alternately on the other. The foundation beam is bent downward at the lower end of the compression-side stud, and a pulling force acts on the anchor bolt at the lower end of the tension-side stud, and the foundation beam is bent upward by the pulling force. Furthermore, when a high-strength earthquake-resistant wall is added to the relatively flexible ramen structure, the stress borne by the earthquake-resistant wall is increased, and the pulling force acting on the anchor bolt is further increased.

  In order for this seismic wall to function sufficiently, it is essential to design the foundation beam so that it can withstand these forces, and the adhesion strength of the anchor bolt exceeds the pull-out force. However, when adding a seismic wall for seismic reinforcement of an existing building, the strength of the existing foundation beam may be insufficient, or anchor bolts may be post-installed and sufficient adhesion strength may not be obtained. . In addition, in a newly built building, such correspondence is relatively easy, but it leads to an increase in cost.

  Patent Document 2 proposes an energy absorbing member that bears a horizontal force but slides in the material axis direction and does not act. This energy absorbing member is disposed between the upper structure and the lower structure and resists loads other than the material axis direction. The energy absorbing member can absorb energy by fitting a fitting member and a member to be fitted in contact with each other inside and outside, and when a horizontal force is applied, a portion having low rigidity other than the contact surface yields. It is configured as follows. For this reason, it can be made free with respect to the load of a material axial direction, and energy other than a material axial direction can be absorbed effectively. Therefore, even when an applied load other than the material axis direction is applied during an earthquake, no force is applied in the material axis direction.

Japanese Patent Laid-Open No. 02-197637 JP 2001-107601 A

  However, when a horizontal force is applied to the structure including the energy absorbing member, the fitting member and the fitted member have contact surfaces, and thus the force in the material axis direction is not transmitted between them. The moment of things is transmitted. Therefore, for example, when the input horizontal force is P and the height of the energy absorbing member is h1, a moment (P · h1) acts on the fitted member fixed to the lower structure. Then, at the bolt position on the side where the member to be fitted of the lower structure is about to rise, when the distance from the bolt to the end of the base plate opposite to the bolt is w1, the pulling force (P · h1) / W1) acts, and at the position of the end of the base plate, a pushing force having the same magnitude as this pulling force acts. For this reason, adhesion strength that can withstand this pull-out force is required at the embedded portion of the bolt, and the lower structure must be strong enough to withstand these forces. In such cases, strength problems may occur.

  An object of the present invention is to reduce the force acting on a frame such as a beam to which the lower end portion of the earthquake-resistant wall is fixed or the force acting on a fixture such as an anchor bolt fixed to the frame for fixing as much as possible. This is to provide a seismic wall that can improve the seismic performance without increasing the strength of surrounding members such as beams in newly built buildings, and can easily perform seismic reinforcement of existing buildings. .

In order to solve the above-mentioned problem, a seismic wall according to the present invention comprises two pillars erected with a predetermined interval, and an upper beam and a lower beam connected to the two pillars. A seismic wall installed in the structural surface of the frame, comprising two vertical members arranged between the upper beam and the lower beam, and a damping material fixed between the two vertical members, The two vertical members are joined to the upper beam at the upper end, and only the horizontal force is transmitted to the lower beam at the lower end so that the vertical force and moment are Are joined so as to be supported by a vertical roller that is not transmitted, and the joint between the lower end of the vertical member and the lower beam is a plate-like base portion and a plate-like stand-up having a bolt hole that stands from the base portion. A constraining member placed and fixed on the upper surface of the lower beam, and a bolt hole in the vicinity of the lower end formed in a plate shape Is constructed by connecting the Kitatezai and a bolt, of the lower end of the longitudinal member and the upright portion, a two other is in the one either, the one to sandwich said other The upright portion and the lower end portion of the vertical member extend in the direction of the surface of the casing, and either one of the bolt hole of the upright portion and the bolt hole near the lower end portion of the vertical member is A long hole in the vertical direction, the other is a round hole, and the bolt is inserted in a state where the round hole is located in the center of the long hole, and when a horizontal force is applied, the bolt is inserted into the long hole. In contrast, it is configured to be allowed to move in the vertical direction.

  Here, the damping material refers to the general structure that can absorb the seismic energy by being deformed at the time of the earthquake, and is composed of, for example, ordinary steel material or extremely low yield point steel, and more than other components. Some have steel dampers with low rigidity to facilitate plastic deformation

  In the earthquake-resistant wall, the upper beam can be a floor beam on the second floor, and the lower beam can be a foundation beam made of reinforced concrete.

  The seismic wall according to the present invention is a vertical roller support in which only horizontal force is transmitted and vertical force and moment are not transmitted to the lower ends of the two vertical members constituting the damping means having the damping material. Thus, when the earthquake resistant wall receives a horizontal force, only the horizontal force is distributed to the two vertical members and transmitted to the respective restraining members. Therefore, the horizontal force acting on one restraining member is almost half of the horizontal force borne by the seismic wall. Moreover, since this horizontal force acts at the lower end of the longitudinal member, that is, a position close to the lower beam, even if a moment acts on the lower beam due to the horizontal force transmitted from the longitudinal member, it becomes a very small value. Therefore, an increase in the load on the lower beam due to the provision of the earthquake-resistant wall can be suppressed, and an economical design can be performed. Particularly, it can be suitably used when performing earthquake-proof reinforcement on existing buildings. .

  The vertical roller support is composed of a plate-like base portion and a plate-like standing portion standing from the base portion and having a bolt hole, and is formed in a plate shape with a restraining member placed and fixed on the upper surface of the lower beam. A vertical member having a bolt hole in the vicinity of the lower end portion is connected by a bolt, and one of the bolt hole in the standing portion and the bolt hole in the vicinity of the lower end portion of the vertical member is long in the vertical direction. It can be realized very simply by inserting a bolt with the long hole and the other as a round hole, with the round hole positioned at the center of the long hole.

  In particular, when the upper beam is a floor beam on the second floor and the lower beam is a foundation beam made of reinforced concrete, that is, when the above-mentioned seismic wall is installed on the first floor part of the building, it is necessary to fix the vertical member to the foundation beam Since a large pulling force does not act on such an anchor bolt, it can be handled with a relatively simple one such as a chemical anchor, which is economical.

  Hereinafter, the best mode of a seismic wall according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram for explaining the structure of a seismic wall. FIG. 2 is a diagram illustrating the configuration of the vibration damping means. FIG. 3 is a view for explaining the structure of the leg portions of the vertical members constituting the vibration damping means. FIG. 4 is a diagram for explaining the behavior of the shear wall during a medium earthquake. FIG. 5 is a diagram for explaining the behavior of the earthquake-resistant wall during a large earthquake.

(First embodiment)
The seismic wall shown in FIG. 1 includes an upper beam 1 and a lower beam 2 made of H-shaped steel and an upper beam 1 in a frame 4 of a rigid frame structure made up of two columns 3 and 3 made of square steel pipes. A vibration damping means A having two longitudinal members 10 and two damping members B fixed between the two longitudinal members 10 is arranged between The upper end of the vertical member 10 is joined to the upper beam 1 and the lower end is joined to the lower beam 2 so that only horizontal force is transmitted and vertical force and moment are not transmitted. Yes.

  As shown in FIG. 2, the two vertical members 10 constituting the vibration damping means A have a column head 10 a formed at the upper end, and the column head 10 a is a bolt (not shown) with respect to the lower flange 1 a of the upper beam 1. It is joined using. Therefore, the upper end of the vertical member 10 moves in the same direction as the upper beam 1 moves in the horizontal direction.

  As shown in FIG. 3, columnar portions 12 each having a T-shape in a side view including a mounting piece 12a and two plates 12b are formed at the lower ends of the two vertical members 10, respectively. A round bolt hole 12c is formed at the position.

  Further, on the upper surface of the upper flange 2a of the lower beam 2 and at positions corresponding to the two vertical members 10 of the vibration damping means A, a plate 13 serving as a plate-like base portion and a plate serving as a plate-like standing portion A restraining member 13 having a T-shape in a side view composed of 13b is attached by aligning the four holes formed in the attachment piece 13a with the four holes on the upper surface of the upper flange 2a and inserting bolts, An elongated bolt hole 13c is formed at a predetermined position of 13b to allow for a slight clearance with a bolt that is long in the vertical direction and inserted in the horizontal direction.

  And the restraint member 13 is previously fixed to the upper flange 2a of the lower beam 2 with a bolt (not shown), and the plate 13b of the restraint member 13 is attached by the two plates 12b of the column base 12 formed at the lower end of the longitudinal member 10. By inserting the bolt 14a into the bolt holes 12c and 13c and screwing the nut 14b so as to be sandwiched, only the horizontal force is transmitted to the lower beam 2 at the lower ends of the two vertical members 10, and the vertical members 10 are vertically The direction force and moment are joined without being transmitted.

  In order to support the vertical roller in which only the horizontal force is transmitted to the lower beam 2 at the lower ends of the two vertical members 10 and the vertical force and moment are not transmitted, (1) the bolt 14a is a half bolt As described above, the loose state is maintained even if the nut 14b is screwed. (2) A film made of fluororesin or molybdenum disulfide is formed on the surface of the plate 12b of the column base 12 and the plate 13b of the restraining member 13 to reduce the frictional force acting on the contact surface between them and slide with a slight force. To be configured. (3) There are methods such as interposing both contact surface bearings.

  Normally, the position of the bolt 14a with respect to the bolt hole 13c is set at a substantially central position. Therefore, even if a long-term load is applied above the longitudinal member 10, the lower end of the longitudinal member 10 moves downward, so that the load is not transmitted to the lower beam 2 at the position of the restraint metal 13. Moreover, although the bolt 14a moves up and down according to the magnitude of the horizontal force at the time of an earthquake, the length of the bolt hole 13c in the up and down direction is such that the bolt 14a does not move even when the assumed maximum horizontal force is applied. The upper and lower end portions of the bolt hole 13c are set so as not to contact the plate 13b, and vertical movement is always allowed.

  In order to transmit a horizontal force to the restraining member 13 at the lower ends of the two vertical members 10, the vertical dimension of the bolt hole 13 c provided in the restraining member 13 is set in the horizontal direction. When a force is applied, the bolt 14a immediately contacts the plate 13b at the left and right end portions of the bolt hole 13c.

  In this embodiment, the column base 12 includes the two plates 12a facing each other, but one plate 12a may be provided. Alternatively, one plate 12a of the column base 12 may be provided and two plates 13b of the restraining member 13 may be arranged to face each other. Alternatively, the bolt hole 12c of the plate 12a of the column base 12 may be a long hole, and the bolt hole 13c of the plate 13b of the restraining member 13 may be a round hole.

  The damping means A is composed of two longitudinal members 10 and two damping members B arranged in the vertical direction between them.

  The damping material B includes a steel damper 20 and two frame bodies 21. The steel damper 20 is made of an extremely low yield point steel and is formed in a substantially butterfly shape, and is configured so that a central constricted portion can be deformed and absorb seismic energy according to the acting shear force. Yes. The frame body 21 is formed in a substantially isosceles triangular shape by connecting a long side member 21a serving as a base and oblique side members 21b and 21c serving as oblique sides by a connecting member 21d, and a horizontal member 21e is further formed into a long side member 21a. It is arranged from the intermediate position to the connecting member 21d and has high rigidity. The steel damper 20 is bolted to the connecting member 21e of the frame 21, and is configured to be replaceable when deteriorated.

  The damping material B is fixed in such a manner that the connecting members 21e are opposed to each other by bolting the two frames 21 with the long side member 21a on the inner surface of the vertical member 10 respectively. The slanted side members 21b and 21c are attached to the side member 21a, and the steel damper 20 is fixed to the connecting member 21e by bolt joining between the tops of the slanted side members 21b and 21c.

  In the damping material B, when a relative displacement occurs in the horizontal direction between the upper beam 1 and the lower beam 2 in accordance with the horizontal force acting at the time of the earthquake, the opposing frame body 21 is moved along with this displacement. A relative displacement in the vertical direction occurs. The displacement at this time acts as a shearing force on the steel material damper 20, and acts on the hypotenuse members 21b and 21c as a tensile force and a compressive force. And the steel damper 20 absorbs the acting shear force.

  In the vibration damping means A configured as described above, the upper ends of the two vertical members 10 are joined to the lower flange 1a of the upper beam 1, and the lower ends thereof are previously connected to the upper flange 2a of the lower beam 2 via the column bases 12. The bolts 14a and nuts 14b are joined to the restraining member 13 that is fixed. And by arranging the damping means A between the upper beam 1 and the lower beam 2 in this way, a seismic wall is formed.

  In the seismic wall configured as described above, all or most of the vertical load acting on the upper beam 1 is normally borne by the two columns 3 and the column base portion is formed at the lower ends of the two vertical members 10. 12 or the restraint member 13 is hardly or not transmitted to the lower beam 2. Accordingly, the installation of the seismic wall causes little or no increase in the load acting on the lower beam 2.

  When the horizontal force acting during the earthquake causes a horizontal relative displacement (horizontal displacement) between the upper beam 1 and the lower beam 2, the two vertical members 10 have the upper ends together with the upper beam 1. It moves in the same direction, the lower end is restrained by the restraining member 13 attached to the lower beam 2, stays at the initial position, and the entire seismic wall is deformed to form a parallelogram.

  Accordingly, the two vertical members 10 are inclined with the horizontal displacement of the upper beam 1 and the lower beam 2. When the two vertical members 10 are inclined, the lower ends of the respective vertical members 10 are restrained from moving in the horizontal direction, so that the bolts 14a of the column base portions 12 of the vertical members 10 and the restraining members 13 are The reaction force acts by abutting at the left and right end portions of the bolt hole 13c, and this reaction force acts as a resistance.

  The inclination of the two vertical members 10 changes according to the amount of displacement of the upper beam 1 and the lower beam 2, and the magnitude of the reaction force also changes according to the amount of displacement.

  As shown in FIG. 4, the two vertical members 10 are inclined in accordance with the relative displacement of the upper beam 1 and the lower beam 2 according to the applied horizontal force, and a bolt 14 a and a bolt hole 13 c are generated during a small and medium earthquake. The reaction force is generated by the contact with the upper beam 1 and acts as a resistance against the upper beam 1 through one longitudinal member 10 (two longitudinal members 10 are alternately arranged). That is, the vibration damping means A itself becomes a resistance and can bear the horizontal force. For this reason, it becomes possible to suppress the deformation of the building without the plastic deformation of the steel damper 20.

  At this time, since the vertical force and moment are not transmitted between the column base 12 formed at the lower end of the vertical member 10 and the restraining member 13, the lower beam 2 is pulled up or pushed in by these forces. Force does not work.

  The horizontal force is transmitted between the column base 12 formed at the lower end of the vertical member 10 and the restraining member 13, and the horizontal force P acting on the earthquake-resistant wall causes the restraining member 13 to fall. Will be the power to try. In this case, a pulling force against the lower beam 2 acts on the bolt that fixes the side to which the mounting piece 13a is lifted, and the values thereof are the horizontal force P / 2 acting on the bolt 14a and the center of the bolt 14a from the upper surface of the upper flange 2a. Is expressed by a value (P / 2 · h2 / w1) obtained by dividing the product with the dimension h2 up to the dimension w2 from the end edge portion 13a1 of the mounting piece 13a serving as a fulcrum of the fall to the bolt. Further, a pushing force having the same magnitude as the pulling force acts on the end edge portion 13a1 of the mounting piece 13a. However, since h2 is extremely small compared to the distance between the upper beam 1 and the lower beam 2 (the floor height of the building), the pulling-out force and pushing-in force are extremely small values, and these two forces are close to each other at close positions. Since it acts in the direction of canceling out, a large force does not act on the attachment position of the restraining member 13 of the lower beam 2. This level is negligible when compared with the effect when the lower ends of the vertical members are joined by a general method.

  In the event of a large earthquake, as shown in FIG. 5, the inclination of the two vertical members 10 increases, and a compressive force is generated in the vertical member 10 due to the contact between the bolt 14a and the bolt hole 13c on one vertical member 10. Then, the further inclination of the longitudinal member 10 is transmitted to the damping material B, and a shearing force acts on the steel damper 20. And the steel damper 20 repeats plastic deformation according to the applied shearing force, absorbs energy, quickly attenuates shaking, and can prevent damage to the building.

  As described above, even when the steel damper 20 repeats plastic deformation and absorbs energy, the force acting on the lower beam 2 from the two vertical members 10 can be ignored and is peeled off to the fixed restraining member 13. Directional force does not act.

  In particular, in such a shear wall, the damping means A is arranged between the upper beam 1 and the lower beam 2 and the upper end is joined to the upper beam 1 and the lower end is joined to the lower beam 2 via the restraining member 13. Can be configured. In particular, in the case of a housing in which a plurality of bolt holes are formed in advance at a predetermined pitch based on a planar module on the flanges of the upper beam 1 and the lower beam 2 as in an industrialized house, it is installed without requiring large construction. It is possible. For this reason, it is advantageous to adopt this earthquake resistant wall when enhancing the earthquake resistance of existing buildings.

(Second embodiment)
Next, a second embodiment of the earthquake resistant wall according to the present invention will be described. The seismic wall of the present invention comprises an upper beam, a reinforced concrete foundation beam, and two vertical members arranged between the upper beam and the foundation beam in the first-floor structure of the two-column frame. A vibration damping means having a vibration damping material fixed between the two vertical members is arranged, the upper ends of the two vertical members constituting the vibration damping means are joined to the upper beam, and the lower end is the base beam. On the other hand, it is joined so as to be a vertical roller support in which only a horizontal force is transmitted and a vertical force and moment are not transmitted.

  That is, it is a building in which the above-mentioned seismic wall is configured in the first floor, and if the lower beam 2 in the above-mentioned seismic wall is replaced with the foundation beam 2, the configuration is exactly the same.

  The earthquake-resistant wall of this invention is demonstrated using FIG. This seismic wall is composed of two vertical beams arranged between the upper beam 1 and the foundation beam 2 in the first-floor structure 4 of the frame composed of the upper beam 1, the foundation beam 2, and the two columns 3. A damping means A having a material 10 and two damping materials B fixed between the longitudinal members 10 is arranged, and the upper ends of the two longitudinal members 10 constituting the damping means A are placed upward. It is joined to the beam 1 and its lower end is joined to the foundation beam 2 so as to be a vertical roller support in which only a horizontal force is transmitted and a vertical force and moment are not transmitted.

  That is, the restraint member 13 shown in FIG. 3 is fixed to the foundation beam 2 via an anchor bolt (not shown), and the column base member 12 is attached to the lower end portion of the longitudinal member 10. And while joining the upper end of the vertical member 10 to the lower flange 1a of the upper beam 1 using a bolt and joining the lower end of the column base member 12 and the restraining member 13 using a bolt 14a, the upper beam 1 And the foundation beam 2.

  In an earthquake-resistant building having a seismic wall configured in this way, the rigidity of the first floor portion can be made higher than the rigidity of the upper floor portion, and the interlayer deformation angle of the first floor portion can be reduced. In addition, as in the first embodiment, even if a seismic wall is added, a large force is not applied to the foundation beam 2 at the time of the earthquake. be able to.

  Further, since the pulling force by the anchor bolt fixing the restraining member 13 to the foundation beam 2 can be set to an extremely small value, the anchor bolt necessary for fixing the longitudinal member 10 to the foundation beam 2 is a chemical anchor. It is possible to cope with relatively simple things such as. For this reason, it is advantageous when it is adopted to increase the rigidity of the first floor portion of an existing building.

  The seismic wall according to the present invention is advantageously employed not only in a new building but also in an existing building when it is necessary to increase the rigidity of the frame.

It is a figure explaining the structure of a seismic wall. It is a figure explaining the structure of a damping means. It is a figure explaining the structure of the leg part of the vertical member which comprises a damping means. It is a figure explaining the behavior of a shear wall at the time of a medium and small earthquake. It is a figure explaining the behavior of a shear wall at the time of a big earthquake.

A Damping means B Damping material 1 Upper beam 1a Lower flange 2 Lower beam, foundation beam 2a Upper flange 3 Column 4 Frame construction 10 Vertical member 10a Column head 12 Column base 12a Mounting piece 12b Plate 12c Bolt hole 13 Restraint Member 13a Mounting piece 13b Plate 13c Bolt hole 14a Bolt 14b Nut 20 Steel damper 21 Frame 21a Long side material 21b, 21c Slope side material

Claims (2)

A seismic wall installed in a frame of a frame comprising two columns erected with a predetermined interval, and an upper beam and a lower beam connected to the two columns,
Comprising damping means having two longitudinal members arranged between the upper beam and the lower beam and a damping member fixed between the two longitudinal members,
The two vertical members are joined to the upper beam at the upper end, and the lower end is a vertical roller support that transmits only the horizontal force to the lower beam and does not transmit the vertical force and moment. Are joined to
The joint between the lower end of the vertical member and the lower beam is composed of a plate-like base portion and a plate-like standing portion that rises from the base portion and has bolt holes, and is placed and fixed on the upper surface of the lower beam. A constraining member and a longitudinal member having a bolt hole in the vicinity of a lower end formed in a plate shape, and are configured by connecting with a bolt,
Of the upright part and the lower end of the longitudinal member, either one is one and the other is two, and the other is sandwiched between the other,
The upright portion and the lower end portion of the longitudinal member extend in the direction of the surface of the casing,
Of the bolt holes in the upright portion and the bolt holes in the vicinity of the lower end of the vertical member, either one is a long hole that is long in the vertical direction, the other is a round hole, and the round hole is in the center of the long hole. The earthquake-resistant wall, wherein the bolt is inserted in a state where it is positioned and the bolt is allowed to move vertically with respect to the elongated hole when a horizontal force is applied. .   The earthquake-resistant wall according to claim 1, wherein the upper beam is a floor beam on the second floor, and the lower beam is a foundation beam made of reinforced concrete.

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