JP2017043911A - Aseismatic reinforcement structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aseismatic reinforcement structure capable of effective aseismatic reinforcement, even of a structure using a skeletal member having a low stickiness characteristic.SOLUTION: An aseismatic reinforcement structure has a metallic diagonal member fitted on a steel skeletal member for aseismatic reinforcement. The aseismatic reinforcement structure includes a metallic enclosing plate that surrounds a range of the skeletal member from four sides and has the diagonal member connected thereon directly or through an interposing member. The enclosing plate is of a bent plate form, and has a plate surface placed opposite and close to an outer periphery of the skeletal member at a plurality of locations. Furthermore, the enclosing plate surrounds the skeletal member without being rigidly connected to the skeletal member.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a seismic reinforcement structure for reinforcing a building by attaching a diagonal member to a frame member.

In the past, it has been generally practiced to retrofit existing structures by attaching diagonal members to the frame members. For example, the strength of a building against horizontal force is improved by attaching diagonal materials between columns and beams.
Conventionally, some proposals have been made to attach an oblique material to a column or the like without performing welding and perform seismic reinforcement (see Patent Documents 1 to 4). According to Patent Documents 1 to 4, in order to perform welding at a site where a building is installed, a large-scale curing is required and the cost is increased, or the quality of welding is lowered depending on the environment of the site. The problem is pointed out.

JP 2013-032688 A JP 2013-083040 A JP 2013-177797 A JP 2014-101655 A

  Railway facilities include buildings that use old rails as frame members. For example, the bottom surfaces of two old rails are joined together and used as one frame member. The old rail has a large amount of carbon, and has a characteristic that it becomes less viscous when welded. For this reason, when a bending moment is applied to the frame member using the old rail to which welding has been applied, the vicinity of the welded portion may be damaged before the frame member yields and plasticizes.

From such characteristics, it is desirable not to use welding in the method of attaching the diagonal member to the frame member. In addition, it is considered that it is desirable to use a material having a high viscosity at the joint between the diagonal member or the frame member and the diagonal member, and to make one of them plastic before the frame member using the old rail having a low viscosity.
The present invention provides effective seismic reinforcement not only for buildings using general frame members but also for buildings using frame members with less stickiness like old rails. It aims to provide a seismic reinforcement structure that can be used.

In order to achieve the above object, the present invention is a seismic reinforcement structure in which a metal diagonal member is attached to a steel frame member and reinforced,
A metal enclosure that encloses a range of the framework member from four sides and to which the diagonal member is joined directly or via an intervening member;
The enclosure plate has a shape obtained by bending a plate, and the plate surfaces are opposed and close to a plurality of locations on the outer periphery of the framework member, and the framework member is enclosed without being rigidly joined to the framework member. It is said.

  According to this configuration, the surrounding plate surrounds the frame member without being rigidly joined to the frame member. Therefore, when a horizontal force is applied to the frame member and the diagonal member, and a relatively large force is generated at the joint portion between the frame member and the diagonal member, the frame member is first moved while the enclosure plate is displaced or elastically deformed. Support a part of. Thereby, the rigidity of the frame member can be improved without excessively concentrating bending stress on the joint portion of the frame member with the diagonal member. Therefore, even if it is a framework member with little stickiness, it can prevent the situation where stress concentrates and damages to a joint part, and an effective seismic reinforcement of a building can be performed by using diagonal members and a shroud. .

Preferably, the surrounding plate may surround the frame member by opening a space inside a bent portion of the plate.
According to this configuration, it is possible to more reliably avoid the bending stress from being excessively concentrated on the joint portion of the frame member with the diagonal member due to the deformation of the bent portion of the plate.
Preferably, the yield strength of the shroud is configured to be smaller than the yield bending strength of the frame member.
According to this structure, before the frame member yields and bends, the diagonal member and the shroud yield and absorb force. Therefore, it is possible to effectively reinforce the building even against a very large vibration in which a part of the building yields.

Also preferably, the shroud is
A first portion surrounding one side of the framework member and having a pair of flange portions at one end and the other end;
A second portion surrounding the other side of the framework member and having a pair of flange portions at one end and the other end;
The pair of flange portions of the first portion and the pair of flange portions of the second portion are joined to each other, and the surrounding plate surrounds the frame member,
A part of the interposed member is joined to the flange portion of the first portion and the flange portion of the second portion,
It is good to comprise so that the said diagonal material may be joined to the other site | part of the said interposed member.
According to such a structure, when providing a surrounding board and diagonal material in the existing building, construction can be performed easily.

Preferably, the frame member is configured by joining two railroad rails to each other at the bottoms,
The surrounding plate has a hexagonal inner periphery in a cross section perpendicular to the longitudinal direction of the frame member, and two surfaces corresponding to two sides sandwiching the first vertex of the hexagonal shape are one of the two rails. The two surfaces corresponding to the two sides that are adjacent to and opposite to both edge portions of the top of the rail of the rail and sandwich the second vertex on the opposite side of the first vertex of the hexagonal shape are the two rails. It is good that it is close to and opposite to both edge portions of the top of the other rail.
When two rails are joined to the bottom surface of the rail to form a frame member, the cross-sectional dimension of the frame member is the vertical dimension (the dimension from the top of one rail to the top of the other rail). It is about twice as long as the horizontal dimension (the horizontal dimension of the rail). Therefore, depending on how the frame members are enclosed, the enclosure plate may not be stably fixed, or the enclosure plate may be difficult to be bent. However, according to the said structure, a surrounding board can be stably fixed to a frame member, and the bending shaping | molding of a surrounding board can also be performed easily.

  According to the seismic reinforcement structure of the present invention, it is effective not only for the seismic reinforcement of a building using a general frame member but also for a building using a frame member having a less sticky characteristic like an old rail. The effect that it is possible to perform the seismic reinforcement is obtained.

It is a perspective view which shows the earthquake-proof reinforcement structure which concerns on embodiment of this invention. It is a front view which shows the earthquake-proof reinforcement structure which concerns on embodiment of this invention. The cross section of the junction part of the pillar and diagonal of an embodiment is shown, (a) is an AA line sectional view of Drawing 2, (b) is a sectional view of the 1st modification, and (c). It is sectional drawing of a 2nd modification. It is a graph explaining the yield strength of a shroud. It is the graph which compared the case where a pillar and a diagonal are joined using a surrounding board, and the case where it joins rigidly. It is a graph which shows an example of the result of the earthquake-proof experiment of the earthquake-proof reinforcement structure which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing a seismic reinforcement structure according to an embodiment of the present invention. FIG. 2 is a front view showing the seismic reinforcement structure according to the embodiment of the present invention. 3 shows a cross section of the joint between the column and the diagonal member of the embodiment, (a) is a cross-sectional view taken along the line AA in FIG. 2, (b) is a cross-sectional view of the first modification, (C) is sectional drawing of a 2nd modification.
The seismic reinforcement structure according to the embodiment of the present invention is a structure in which the diagonal member 30 is provided between the column 100 and the beam 200 as a frame member to improve the earthquake resistance of the building. This seismic reinforcement structure can be added later to existing buildings.

The building having the seismic reinforcement structure of the present embodiment includes a column 100, a beam 200, a surrounding plate 10, a diagonal member 30, and joining plates 21 and 22. The pair of joining plates 21 and 21 correspond to an example of an interposed member according to the present invention.
The pillar 100 has a configuration using an old rail of the railway, and is configured by joining the bottom portions b of the two rails 101 and 101 of the railway. The tops h, h of the two rails 101, 101 are arranged in opposite directions. The bottom part b and the top part h of the rail 101 mean the bottom part and the top part when the rail is laid on the railway line.

The enclosure plate 10 is a member that connects the column 100 and the diagonal member 30 and is configured by bending a steel plate. The surrounding board 10 makes a board | plate surface oppose and adjoin to the several location of the outer periphery of the pillar 100, and encloses the range of the height direction of the pillar 100 from four directions, without being rigidly joined with the pillar 100. FIG.
Further, the enclosure plate 10 is not particularly limited, but a space may be provided inside the bent portion of the plate so as to enclose a range of the pillar 100.
Here, the rigid joint means a joint in which an external force is applied to the framework and the joint is not deformed even when the framework is deformed, and includes a rigid joint using welding or a bolt, a joint using a metal band that is firmly tightened, and the like.

Hereinafter, a specific example of the surrounding board 10 suitable for the pillar 100 of this Embodiment is demonstrated. As shown in FIG. 3A, the inner peripheral shape of the cross section of the enclosure 10 of the present embodiment is a hexagon, and the two surfaces S1 and S2 sandwiching the first vertex P1 of the hexagon are one rail. 101 are arranged so as to be close to and opposite to both edge portions E1 and E2 of the head top portion h. Further, the two surfaces S4 and S5 sandwiching the second vertex P4 opposite to the first vertex P1 are arranged so as to be close to and opposed to both edge portions E3 and E4 of the top portion h of the other rail 101, respectively. Further, the six hexagonal vertices P1 to P6 of the inner periphery of the cross section are separated from the outer peripheral surface of the column 100, and a space is provided inside the vertices P1 to P6. Further, the remaining two surfaces S3 and S6 (which may include the end surface of the joining plate 21) are opposed and close to the both end portions E5 and E6 of the bottom surface portions b and b of the two rails 101. The enclosure plate 10 is not joined to the column 100 by welding or the like, but is fixed by joining the diagonal member 30 and contacting the column 100.
The proximity between the two rails 101 and the inner peripheral surfaces S1 to S6 of the surrounding plate 10 may be a proximity in which a slight gap is provided, or may be a close proximity without a gap.

In addition, the cross-sectional shape of the surrounding board 10 can be changed variously. For example, as shown in FIG. 3B, the cross-sectional shape of the surrounding plate 10 may be a one-side trapezoidal shape. 3B, two surfaces S11 and S12 corresponding to two oblique sides of one trapezoid are close to and opposite to both edge portions E1 and E2 of the top portion h of one rail 101, respectively. . Similarly, the two surfaces S13 and S14 corresponding to the two hypotenuses of the other trapezoid are adjacent to and opposed to both edge portions E3 and E4 of the top portion h of the other rail 101, respectively. Even in such a shape, a space is provided inside the bent portions P <b> 11 to P <b> 14 of the enclosure plate 10 while the enclosure plate 10 holds the pillar 100.
Moreover, as shown in FIG.3 (c), it is good also as a structure which bent the bent part of the surrounding board 10 not in bending but in the curved shape. In the surrounding board 10 of FIG. 3C, one curved surface S21 is close to and opposed to both edge portions E1 and E2 of the top portion h of one rail 101. Similarly, the other curved surface S22 is close to and faces both edge portions E3 and E4 of the top portion h of the other rail 101, respectively. Even in such a shape, a space is provided inside the bent portions P21 and P22 of the enclosure plate 10 while the enclosure plate 10 holds the pillar 100.

  The enclosure plate 10 is configured by joining a first part 11 and a second part 12 that can be separated into two parts by bolts or the like. The first portion 11 surrounds one side of the pillar 100 and has a pair of flanges 13 and 14 at one end and the other end in the circumferential direction of the pillar 100. The second portion 12 surrounds the other side of the column 100 and has a pair of flanges 15 and 16 at one end and the other end in the circumferential direction of the column 100. One flange 13 of the first portion 11 and one flange 15 of the second portion 12 are joined by a bolt or the like with one joining plate 21 interposed therebetween. Similarly, the other flange 14 of the first portion 11 and the other flange 16 of the second portion 12 are joined together by a bolt or the like with one joining plate 21 interposed therebetween.

  The joining plate 21 is a plate-like member for joining the enclosure plate 10 and the diagonal member 30. A part of each of the two joining plates 21 is rigidly joined to the surrounding plate 10, and is arranged symmetrically with respect to the vertical center line of the column 100. The end portions of the two diagonal members 30, 30 are joined to the two joining plates 21 by bolts or the like.

  The joining plate 22 on the beam 200 side is a plate-like member for joining the beam 200 and the diagonal member 30. The two diagonal members 30, 30 are rigidly joined to the two joining plates 22 by bolts or the like. The method for joining the beam 200 and the diagonal member 30 is not particularly limited. For example, if the beam 200 is configured using an old rail, the same method as the method for joining the column 100 and the diagonal member 30 using the shroud 10 is used. A joining method may be applied. Alternatively, when the beam 200 has sufficient resistance, the beam 200 and the joining plate 22 may be rigidly joined.

<Strength of shroud>
Next, the proof stress of the enclosure board 10 is demonstrated.
FIG. 4 is a graph for explaining the yield strength of the enclosure plate 10. The graph of FIG. 4 schematically shows the relationship between the angle change amount θ of the column 100 and the bending moment M generated in the enclosure plate 10 when a horizontal force is applied to the seismic reinforcement structure. As shown in FIG. 2, when the beam 200 is fixed and a horizontal force is applied to a part of the column 100, the angle change amount θ is determined from the initial position of the column 100 centering on the junction O with the beam 200. The amount of change in angle is shown.
In the graph of FIG. 4, Mu represents a bending moment generated in the shroud 10 when the minimum horizontal force necessary for earthquake resistance is applied to the building. cMy indicates the bending moment of the column 100 when the column 100 yields. Hereinafter, these are referred to as a necessary minimum bending moment Mu and a yield bending moment cMy.

The required minimum bending moment Mu is the structural characteristic coefficient Ds and shape characteristic coefficient Fes of the building, the seismic layer shearing force Qi when the layer shearing force coefficient Co = 1.0, the coefficient α that increases the seismic performance, the column From the length h1 from the lower end of 100 to the joint portion of the diagonal member 30, for example, it can be obtained as shown in the following equation (1).
Mu = Ds × Fes × Qi × α × h1 / 2 (1)
The yield bending moment cMy can be obtained from the yield stress degree σy of the column 100 and the section modulus Z of the column 100, for example, as shown in the following equation (2).
cMy = σy × Z (2)

In the graph of FIG. 4, jM _1/50 indicates a bending moment generated in the enclosure plate 10 when the angle change amount of the column 100 is 1/50, and is hereinafter referred to as enclosure plate bending strength at θ 1/50. The angle change amount “1/50” indicates a value that is a criterion for determining whether to stop using the building because there is a risk of collapse of the building framework. For this reason, the enclosure bending strength jM _1/50 at θ1 / 50 is represented by the intersection of the characteristic line of the bending moment and the line of the angle change amount θ of _1/50 rad.
The shroud 10 is proof set so that it yields and deforms when a bending moment smaller than the bending moment at which the column 100 yields is generated in the column 100. In addition, the proof strength of the shroud 10 is preferably set so that it does not yield and deform even when the minimum horizontal force required for earthquake resistance is applied to the building. Such a condition can be expressed by a relational expression with each bending moment as shown in the following expression (3).
Mu <jM _1/50 <cMy (3)

When such a condition is satisfied, as shown in the graph of FIG. 4, the characteristic line of the bending moment crosses the target performance line L1. The target performance line L1 indicates a range in which the angle change amount θ is 1/50 rad and the bending moment is from the necessary minimum bending moment Mu to the yield bending moment cMy.
The yield strength of the surrounding plate 10 varies depending on the height, thickness, gap between the column 100, material, cross-sectional area of the diagonal member 30, and the like. Therefore, by appropriately selecting the values of these parameters, the enclosure plate 10 can be configured so that the enclosure bending resistance jM _1/50 at θ _1/50 satisfies the condition of Expression (3).

FIG. 5 is a graph comparing the case where the column and the diagonal member are joined using a surrounding plate and the case where they are joined rigidly.
As shown in the characteristic line of the rigid connection in FIG. 5, when the column 100 and the diagonal member 30 are rigidly connected, the relationship between the bending moment of the column 100 and the angle change amount θ greatly deviates from the target performance line L1. . For this reason, when the column 100 having a low-viscosity characteristic is used, the yield strength of the joint portion becomes very large as compared with the yield bending strength of the column 100. Therefore, when a very large horizontal force is generated in a building having such a structure, the pillar 100 yields before the joint yields. In the characteristic line of the rigid joint in FIG. 5, the characteristic line extends to the range of a large bending moment, but it is considered that the column 100 yields before such a large bending moment occurs.

On the other hand, as shown in the characteristic line of the enclosure plate bonding in FIG. 5, in the case of using the enclosure plate 10, an appropriate rigidity can be obtained at the joint portion between the column 100 and the diagonal member 30. The line L1 can be crossed.
FIG. 5 shows characteristic lines when the enclosure plate 10 and both edge portions E1 to E4 of the top part h of the column 100 are in contact with each other, and characteristic lines when there is a slight gap between these parts. ing. When there is a gap, the characteristic line shifts by the gap, but when the gap disappears due to the displacement of the column 100, it can be seen that the same characteristics as when the column 100 is contacted from the beginning can be obtained.

FIG. 6 is a graph showing an example of the result of the earthquake resistance test of the earthquake resistant reinforcement structure according to the embodiment of the present invention.
About the earthquake-proof reinforcement structure which concerns on this Embodiment, when the present inventors conducted an earthquake-proof experiment, it became clear that an earthquake-proof behavior as shown in FIG. 6 was shown. In this seismic test, a large horizontal force is repeatedly applied to the beam 200 or the column 100, and the relative displacement of the column 100 with respect to the beam 200 is observed.
As shown in FIG. 6, when the column 100 and the beam 200 are swung relatively large due to a large horizontal force, first, the out-of-plane bending of the shroud 10 and the bending of the diagonal member 30 on the compressed side develop ( (See sections T1 and T2 in FIG. 6). Thereby, force absorption is performed and yielding of the pillar 100 is avoided. Furthermore, when a large horizontal force is repeated, the diagonal member 30 buckles, and then the displacement of the column 100 increases to one side and reaches the limit point of the seismic experiment (see section T3 in FIG. 6). As described above, according to the seismic reinforcement structure of the present embodiment, the vibration force is absorbed by the yield deformation of the enclosure plate 10 and the diagonal member 30 before the column 100 yields, whereby the column 100 is absorbed. It is considered that problems such as yielding first and plasticizing can be avoided, or the vicinity of the surrounding plate 10 in the column 100 is damaged.

As described above, according to the seismic retrofit structure of the present embodiment, the surrounding plate 10 surrounds the column 100 without rigidly joining the surrounding plate 10 and the column 100. Therefore, when the building is shaken and a relative horizontal force is generated between the column 100 and the beam 200, first, the enclosure plate 10 is elastically deformed, and the column 100 and the diagonal member 30 are connected. Thereby, the rigidity of the column 100 and the beam 200 can be improved without excessively bending stress being concentrated at the joint portion between the column 100 and the diagonal member 30. Therefore, even if it is a building using the pillar 100 which has the characteristic with little stickiness, a seismic performance can be improved.
Furthermore, even if a very large shaking occurs that causes each element of the building to yield, the displacement or deformation of the shroud 10 and the yielding of the diagonal member 30 occur before the column 100 yields. Can absorb the force of shaking. Therefore, effective seismic reinforcement is realized even for such a large shaking.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, in the said embodiment, although the structure which performs earthquake-proof reinforcement to the building using a rail as a frame member is shown, the frame member may use the general cross-section H type steel material.
Moreover, in the said embodiment, some examples were shown about the inner peripheral shape of the cross section of a surrounding board, However, The inner peripheral shape of a surrounding board is not limited to these. For example, when the frame member is displaced relative to the enclosure plate in a direction other than the longitudinal direction of the frame member, the frame member contacts the enclosure plate and the force is transmitted from the frame member to the enclosure plate. The inner peripheral shape of the cross section of the enclosure plate may be any shape as long as the enclosure plate can be deformed out of plane by the space inside the plate.

Moreover, in the said embodiment, although the space example was shown between all the vertexes P1-P6 of the inner peripheral shape of the cross section of the surrounding board 10, and the outer peripheral surface of the pillar 100, one structure was shown. Only the apex of the part needs to have a space inside. Moreover, in the said embodiment, although demonstrated that the enclosure board was formed by the bending process, you may shape | mold in the shape bent beforehand. Further, the bent portion may have a curved shape.
Furthermore, in the above embodiment, the space is provided inside the bent portion of the surrounding plate 10. However, without providing such a space, the pillar 100 may be enclosed by the enclosure plate 10 without rigidly joining the enclosure plate 10 and the pillar 100. For example, in the case of a column having a rectangular cross section, the surrounding plate 10 may be configured to surround a range in the height direction of the column without separating the inner peripheral surface of the surrounding plate 10 and the outer surface of the column. . Even with such a configuration, the same operation as in the embodiment can be obtained.
Moreover, in the said embodiment, although the diagonal material and the surrounding board showed the structure joined via the joining board, the structure joined directly may be employ | adopted.
Moreover, in the said embodiment, the example which calculates the setting value of the yield strength of a shroud was shown by making the angle change amount of the pillar used as the judgment reference | standard of a use stop of a building into 1/50. However, this angle change amount 1/50 is an example, and when a value that is a criterion for determining the suspension of use of a building is determined separately, the setting value of the yield strength of the shroud is similarly calculated based on that value. Good.
In the above embodiment, the structure using the shroud for joining the column and the diagonal member is shown as an example. However, the present embodiment is used for joining the beam and the diagonal member, and joining other frame members and the diagonal member. The structure according to the invention can be applied.

DESCRIPTION OF SYMBOLS 10 Enclosure board 13-16 Flange 21, 22 Joining board 30 Diagonal material 100 Column 101 Rail 200 Beam P1-P6 Vertex h Head top part E1, E2, E3, E4 Both edge part of head part b Bottom part

Claims (5)

A seismic reinforcement structure in which a metal diagonal member is attached to a steel frame member and reinforced,
A metal enclosure that encloses a range of the framework member from four sides and to which the diagonal member is joined directly or via an intervening member;
The enclosure plate has a shape obtained by bending a plate, and the plate surfaces are opposed and close to a plurality of locations on the outer periphery of the framework member, and the framework member is enclosed without being rigidly joined to the framework member. Seismic reinforcement structure.   The seismic reinforcement structure according to claim 1, wherein the surrounding plate surrounds the frame member by opening a space inside a bent portion of the plate.   The seismic reinforcement structure according to claim 1 or 2, wherein the yield strength of the shroud is smaller than the yield bending strength of the frame member. The shroud is
A first portion surrounding one side of the framework member and having a pair of flange portions at one end and the other end;
A second portion surrounding the other side of the framework member and having a pair of flange portions at one end and the other end;
The pair of flange portions of the first portion and the pair of flange portions of the second portion are joined to each other, and the surrounding plate surrounds the frame member,
A part of the interposed member is joined to the flange portion of the first portion and the flange portion of the second portion,
The seismic reinforcement structure according to claim 1 or 2, wherein the diagonal member is joined to another part of the interposition member. The skeleton member is composed of two railroad rails joined to each other at the bottoms,
The surrounding plate has a hexagonal inner periphery in a cross section perpendicular to the longitudinal direction of the frame member, and two surfaces corresponding to two sides sandwiching the first vertex of the hexagonal shape are one of the two rails. The two surfaces corresponding to the two sides that are adjacent to and opposite to both edge portions of the top of the rail of the rail and sandwich the second vertex on the opposite side of the first vertex of the hexagonal shape are the two rails. The seismic reinforcement structure according to claim 1, wherein the structure is adjacent to and opposed to both edge portions of the top of the other rail.

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