JP6996536B2 - Steel plate shear wall - Google Patents

Description

The present invention relates to a wall structure that enhances the earthquake resistance of a building, and more particularly to a steel plate earthquake-resistant wall made of a steel material.

In the conventional general steel plate shear wall 11, as shown in FIG. 8, a rectangular steel plate 13 is arranged in a frame 19 (frame) composed of pillars 15 (studs) and beams 17 of a building, and steel plates are used. The peripheral edges of the four sides of 13 are attached to the columns 15 and beams 17 by welding or bolting with high-strength bolts 23 via the joining members 21 having a T-shaped cross section.

When horizontal external forces such as earthquakes and typhoons are input to the steel plate shear wall 11 from the pillars 15 (studs) and beams 17 of the building, deformation (buckling) occurs so that the wall surface protrudes in the out-of-plane direction, and the bearing capacity. Is significantly reduced. In order to prevent this buckling phenomenon and maintain a stable yield strength against an external force in the horizontal direction, the steel plate 13 is buckled and stiffened.

As a method of buckling stiffening, stiffening with a stiffener is generally performed, and as shown in FIGS. 8 and 9, a method of arranging the stiffener 25 so as to intersect the front and back of the steel plate 13 or As shown in FIG. 10, a method is adopted in which a plurality of stiffeners 25 are arranged at predetermined intervals in the vertical direction.

Further, as another method of buckling stiffening, as disclosed in Patent Document 1, a corrugated steel sheet bent so as to form irregularities on the surface of the steel sheet 13 is used, and the unevenness formed on the steel sheet 13 is used. There is also a method of improving the out-of-plane rigidity to buckle and stiffen.

Japanese Unexamined Patent Publication No. 2013-2032

In the case of buckling stiffening by the stiffener 25, since the stiffener 25 is joined to the steel plate 13 by welding, the steel plate 13 is distorted by the heat during welding. Since this strain significantly reduces the buckling strength of the steel sheet 13, it is necessary to correct the strain precisely, but there is a problem that it takes a lot of time and effort to inspect and correct the strain. Even if the steel plate shear wall 11 is precisely straightened in appearance, residual stress is generated inside the steel plate 13, and this residual stress may cause a decrease in buckling strength.

Further, in the buckling stiffening by the stiffener 25, when the stiffener 25 intersects on the front and back as shown in FIG. 9, in addition to the above problem, it is necessary to invert the steel plate 13 at the time of welding. It takes a lot of trouble.

In the method using the corrugated steel sheet that has been bent, there are concerns about the influence of residual stress due to processing and the decrease in strength of the processed part.
In addition, in the method using a corrugated steel plate, the width of the unevenness becomes large in some cases, which may hinder transportation.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a steel sheet shear wall having excellent buckling performance without being affected by processing labor, heat and residual stress associated with processing.

(1) The steel plate shear wall according to the present invention is a steel plate shear wall constructed by installing steel plates in a frame surrounded by columns and beams.
The steel sheet is a plate thickness changing steel plate in which thick and thin portions are alternately formed in the height direction to form horizontal stripes, or alternately formed in the width direction to form vertical stripes. It is characterized in that the surface of the steel plate is not welded or bent.

(2) Further, in the above-mentioned (1), the change in the plate thickness from the portion having the thickest plate thickness to the portion having the thinnest plate thickness, and from the portion having the thinnest plate thickness to the portion having the thickest plate thickness. It is characterized in that the change in the plate thickness of is gradually changed at a constant rate of change.

In the present invention, by using a steel plate with a variable thickness for a steel sheet seismic wall, for example, a problem caused by distortion due to welding heat and its correction, which is a problem in the conventional example of welding a stiffener, or a bent corrugated steel plate. Since the influence of residual stress due to machining and the problem of decrease in the strength of the machined part, which are problems in the conventional example using, can be completely eliminated and the buckling resistance of the steel plate with changing plate thickness can be expected as it is, a highly reliable steel plate seismic wall can be used. Obtainable.

It is explanatory drawing of the structure of the steel plate shear wall which concerns on one Embodiment of this invention, (a) is a front view, and (b) is a sectional view taken along the line AA. It is explanatory drawing of the plate thickness change steel plate shown in FIG. 1, (a) is a front view, (b) is a side view. It is explanatory drawing of another aspect of the plate thickness change steel plate shown in FIG. 1, (a) is a front view, (b) is a side view. It is explanatory drawing of the mounting method of the plate thickness change steel plate. It is explanatory drawing of the mounting method of the plate thickness change steel plate, (a) is a front view, (b) is a side view. It is explanatory drawing of another aspect of the plate thickness change steel plate shown in FIG. 1, (a) is a front view, (b) is a side view. It is explanatory drawing of another aspect of the plate thickness change steel plate shown in FIG. 1, (a) is a front view, (b) is a plan view. It is explanatory drawing of the structure of the conventional steel plate shear wall, (a) is a front view, (b) is a cross-sectional view of arrow BB. It is explanatory drawing of the stiffening structure of the steel plate shear wall shown in FIG. 8, (a) is a front view, (b) is a side view. It is explanatory drawing of the other stiffening structure of the steel plate shear wall shown in FIG. 8, (a) is a front view, (b) is a side view. It is explanatory drawing of the steel earthquake-resistant wall exemplified in the Example. It is a graph which shows the result of the finite element analysis performed for confirming the effect of this invention.

The steel plate shear wall of the present embodiment will be described with reference to FIGS. 1 and 2.
The steel plate shear wall 1 of the present embodiment is a steel plate shear wall 1 configured by installing steel plates on a frame 19 surrounded by columns 15 and beams 17.
Further, the steel plate is a plate thickness changing steel plate 3 in which thick and thin portions are alternately formed in the height direction to form a horizontal stripe, and the steel plate surface is not welded or bent. It is characterized by being a thing. Here, the steel plate surface refers to a surface corresponding to a wall surface when the plate thickness changing steel plate 3 is installed on the frame 19 to form a steel plate shear wall 1.

As shown in FIG. 2, the plate thickness changing steel plate 3 of the present embodiment is the thickest portion in which the plate thickness gradually increases from the thinnest portion 3a, which is the thinnest, toward the lower end. The plate thickness gradually decreases from the portion 3b, reaches the thinnest portion 3a, which is the thinnest portion, and then gradually increases, and the plate thickness is the highest at the lower end. It is the thinnest part 3a.

In the present embodiment, excluding the upper and lower ends, the thickest portion 3b having the thickest plate thickness has three places in the vertical direction, and the thinnest portion 3a having the thinnest plate thickness has two places. The present invention is not limited to this, and the thickest portion 3b may be at two or more locations.
Since the buckling load increases as the number of changes in the plate thickness increases, for example, as shown in FIG. 3, even if the thickest portion 3b of the plate thickness is 6 places in the height direction. good.

By using the plate thickness changing steel plate 3 in which the plate thickness gradually changes at a constant rate of change in the vertical direction to form a horizontal stripe shape in the present embodiment, the plate thickness is uniformly equal to that of the thinnest portion. Equivalent to or equal to the steel plate shear wall 11 (hereinafter referred to as "equal thickness steel plate shear wall 11") (see FIGS. 9 and 10) in which the steel plate 13 (hereinafter referred to as "equal thickness steel plate 13") is stiffened with a stiffener 25. Further buckling resistance can be expected. This point will be described in more detail as follows.

In the equal-thickness steel plate shear wall, when a horizontal force is applied, the equal-thickness steel plate 13 yields uniformly in the plane and the rigidity is lowered on the entire surface. In order to prevent out-of-plane buckling due to this decrease in rigidity, the stiffener 25 is arranged over the entire wall surface to buckle and stiffen.
On the other hand, in the steel plate shear wall 1 using the plate thickness changing steel plate 3, when a horizontal force is applied, the thinnest part in the plane yields first, and then the thickened part gradually yields, so that the rigidity is increased. The drop is not uniform across the wall. That is, the steel plate shear wall 1 using the plate thickness changing steel plate 3 has a mechanism of delaying the occurrence of buckling and buckling stiffening by distributing the decrease in rigidity in the wall surface. You can expect buckling.
Moreover, in the present embodiment, it is not necessary to weld the stiffener or bend the steel plate, so that the problems associated with the welding and bending as described above do not occur and the steel plate thickness changes. The original buckling resistance of 3 can be expected, and a highly reliable steel plate earthquake-resistant wall 1 can be constructed.

The plate thickness changing steel plate 3 can be manufactured by rolling, and since buckling stiffening does not require welding such as stiffeners or bending, the labor of manufacturing a shear wall can be reduced.

Regarding the installation of the plate thickness changing steel plate 3 on the frame 19, as shown in FIG. 1, the upper and lower beams 17 are bolted to each other via a joining member 5 having a T-shaped cross section. That is, the horizontal piece 5a is welded to the upper side of the plate thickness changing steel plate 3 in an inverted state, and the T-shaped horizontal piece 5a is welded to the lower side of the plate thickness changing steel plate 3. do. Then, the vertical piece 5b of the joining member 5 is bolted to the splicing plate 8 on the beam 17 side with a high-strength bolt 23.

As a method of joining the left and right columns 15 (studs), as shown in FIG. 4, the plate thickness changing steel plate 3 is sandwiched between the splice plates 7 having the same plate thickness changing steel plate 3 and bolted. Then, the splice plate 7 may be joined to the pillar 15 (stud).
Further, as shown in FIG. 5, a splicing plate 9 made of a flat plate having the same thickness as the thinnest portion 3a of the plate thickness changing steel plate 3 is welded to both sides of the plate thickness changing steel plate 3. The splicing plate 9 may be joined to the pillar 15 (stud).

In the steel plate seismic wall 1 configured as described above, since the steel plate thickness changing steel plate 3 is used as the steel plate, for example, a problem caused by distortion due to welding heat and its correction, which is a problem in the conventional example of welding the stiffener 25. Or, the influence of residual stress due to machining, which is a problem in the conventional example using a bent corrugated steel sheet, and the problem of a decrease in the strength of the machined portion are completely eliminated, and the buckling resistance of the sheet thickness changing steel sheet 3 can be expected. A highly reliable steel plate seismic wall 1 can be obtained.

Further, by using the plate thickness changing steel plate 3, when manufacturing the steel plate shear wall 1, there is no welding work, thermal strain correction work, etc. as compared with the method of welding the stiffener 25, and a corrugated steel plate is used. Compared to the case, there is no bending process or inspection work of the influence of residual stress, and there is no trouble in manufacturing the earthquake-resistant wall, and the effect of excellent workability can be obtained.

In the above embodiment, the plate thickness changing steel plate 3 having uneven surfaces formed on both the front and back surfaces is exemplified, but as shown in FIG. 6, one surface is a flat surface and only the other surface is formed. May be an uneven surface.
Further, in the above embodiment, the plate thickness changes regularly in the height direction to form horizontal stripes, but as shown in FIG. 7, the plate thickness is such that vertical stripes are formed. May change in the horizontal direction.

Further, in the above embodiment, the plate thickness gradually changes from the thinnest portion 3a to the thickest portion 3b, but the thickest portion 3b having the thickest plate thickness has a cross section orthogonal to the plate thickness direction. The plate thickness of the thickest portion 3b is constant, the plate thickness of the thinnest portion 3a having the thinnest plate thickness is also constant, and the thickest portion 3b and the thinnest portion 3a are constant so that the shape becomes a rectangular convex portion. May appear alternately.
In this case, the portion connecting the thinnest portion 3a and the thickest portion 3b having a constant plate thickness may be a vertical surface in which the plate thickness changes abruptly, or an inclined surface in which the plate thickness gradually changes. ..

However, by using an inclined surface that gradually changes at a constant rate of change, improvement in plastic deformation performance can be expected, as shown in Examples described later.
In particular, in order to delay the occurrence of buckling and to stiffen the buckling, it is preferable that the plate thickness ratio between the thickest part and the thinnest part is 1.5 or more. On the other hand, when the plate thickness ratio is 2.0 or more, the plastic deformation performance tends to reach a plateau. Therefore, considering economic efficiency, it can be said that a plate thickness ratio of 1.5 to 2.0 is a preferable range.

A finite element analysis was performed to verify the effect of the present invention. The analysis target is a steel plate with a height H = 3240 mm and a width D = 1620 mm. The analysis case is shown in FIG. 11 (a) and 11 (b) are tapered steel sheets to which the present invention is applied, and FIG. 11 (c) is a stiffener-stiffened steel sheet of the prior art carried out as a comparative example.

In FIGS. 11 (a) and 11 (b), thick portions and thin portions are alternately formed in the height direction to form horizontal stripes, and the plate thickness of the thin portions is unified to t = 12 mm. However, the plate thickness of the thick part was set to two types (t = 19,22 mm). In addition, the height of the equal-thickness part is 250 mm, and the height of the sloped part is 497.5 mm.
As a result, the plate thickness ratio (thickest part / thinnest part) of what is shown in FIG. 11A is 1.58, and the plate thickness change rate is 14 mm / m. Further, as shown in FIG. 11B, the plate thickness ratio (thickest part / thinnest part) = 1.83, and the plate thickness change rate is 20 mm / m.

Further, in the comparative example of FIG. 11C, two stiffeners in the vertical direction and five stiffeners in the horizontal direction are arranged at equal intervals. The plate thickness ts of the stiffener was the same as the plate thickness t (= 12 mm) of the thin portion of the steel plate, and the stiffener height was hs = 70 mm.

The material properties are yield strength σy = 235N / mm ² , tensile strength σu = 400N / mm ² , initial rigidity E = 20,5000N / mm ² , secondary rigidity E / 60, and tertiary rigidity E / 1000. The trilinear type is used. In addition, the boundary condition was fixed support on four sides, and a uniform shear stress was applied to the wall surface. A buckling eigenvalue analysis was performed in advance, and the obtained primary mode was input as an initial irregularity so that the out-of-plane displacement was H / 1000, and a geometric nonlinear analysis was performed.

The analysis result is shown in FIG. The vertical axis of FIG. 12 shows the dimensionless shear stress degree (τ / τ _y ) in which the shear stress degree τ is made dimensionless by the yield stress degree τy, and the horizontal axis shows the deformation angle R made dimensionless by the yield deformation angle Ry. The dimensionless deformation angle (R / R _y ) is shown.
In FIG. 12, the result of the tapered steel plate is shown by a solid line, the result of the stiffened steel plate is shown by a broken line, and the maximum yield strength of each curve is shown by a ▽ mark.

In the tapered steel plate (t12-t19) (FIG. 11 (a) plate thickness ratio: 1.58, plate thickness change rate: 14 mm / m), the maximum yield strength exceeds the yield stress degree. Further, it can be seen that the deterioration gradient after the maximum proof stress is gentler than that of the conventional steel plate reinforced with stiffener, and the plastic deformation performance is excellent.
The tapered steel sheet (t12-t22) (Fig. 11 (b) plate thickness ratio: 1.83, plate thickness change rate: 20 mm / m) has a higher yield strength than the conventional stiffener-stiffened steel plate in terms of both yield strength and plastic deformation performance. The plastic deformation performance can be confirmed.

As described above, by applying the present invention, it is demonstrated that the plastic deformation performance is superior to the conventional example, and the thickness of the thick portion is appropriately adjusted according to the size of the wall surface and the thickness of the thin portion. It can be seen that by setting it, it is possible to suppress local buckling of the wall surface, secure the yield strength, and improve the plastic deformation performance.

1 Steel plate shear wall 3 Plate thickness change steel plate 3a Thinnest part 3b Thickest part 5 Joining member 5a Horizontal piece 5b Vertical piece 7 Splice plate 8 Splicing plate (beam side)
9 Splicing plate (plate thickness change steel plate)
<Conventional example>
11 Steel plate shear wall 13 Steel plate 15 Pillar 17 Beam 19 Frame 21 Joining member 23 High-strength bolt 25 Stifuna

Claims (2)

It is a steel plate shear wall constructed by installing steel plates on a frame surrounded by columns and beams.
The steel sheet is a plate thickness changing steel plate in which thick and thin portions are alternately formed in the height direction to form horizontal stripes, or alternately formed in the width direction to form vertical stripes. A steel plate shear wall characterized by the fact that the surface of the steel plate is not welded or bent. The part that connects the part with the thickest plate thickness and the part with the thinnest plate thickness is an inclined surface that gradually changes at a constant rate of change, and the part that connects the part with the thinnest plate thickness and the part with the thickest plate thickness. The steel plate shear wall according to claim 1, wherein is an inclined surface that gradually changes at a constant rate of change .

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