JP2007191912A - Shear panel form seismic response control blade latch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shear panel form seismic response control blade latch which reduces the distortion of a welded part of a flange and a base plate and improves a low-cycle fatigue durability. <P>SOLUTION: The shear panel form seismic response control blade latch is provided with the base plate 4, a pair of the longitudinal flanges 5, 5 with lower ends welded to the base plate 4, and a web 6 having a shear panel 8 which is formed in a longitudinal direction between these flanges 5, 5 and is formed of low yield point steel, and the shear panel form seismic response control blade latch 1 is set between an upper structure 2 and a lower structure 3 to restrain the displacement of the upper structure 2. The web 6 has a lower restraint panel 9 which is continuously formed at the lower side of the shear panel 8 and has a larger yield shear strength than that of the shear panel 8. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a shear panel type vibration control stopper, and more particularly, for example, installed between an upper structure and a lower structure in a bridge or the like, and the displacement of the upper structure is always applied to an earthquake up to a predetermined level. The present invention relates to an anti-seismic stopper that functions as a stopper for restraining and functions as a damper by shear plastic deformation for earthquakes of a predetermined level or higher.

  In recent years, in the field of bridge technology, reaction force dispersion structures and seismic isolation structures are generally used for the purpose of improving the seismic performance of new bridges or for the purpose of seismic reinforcement of existing bridges. The seismic methods based on these structures use an elastic support structure for the bearings, disperse the horizontal reaction force of the lower structure, and lengthen the natural period of the upper structure to avoid resonance with the ground motion, thereby reducing the load on the lower structure. It is a method to reduce the.

  However, these methods (1) reduce the load on the pier but increase the amount of superstructure movement, making it difficult to secure the gap between girders, (2) difficult to apply to soft ground bridges. 3) There are cases where vibration due to live loads at times is a problem, and (4) it is particularly difficult to deal with existing bridges.

  Against this background, the present applicant, in Japanese Patent Application No. 2005-5090, is a shear panel type damping stopper using a movable bearing made of laminated rubber and a low yield point steel (in the specification of the application, a shear panel type damper and Proposal of a bearing structure that combines According to such a bearing structure, the shear panel type damping stopper functions as a stopper that restrains the upper structure at all times or until a low level of earthquake motion (the movable bearing functions as a fixed bearing). After reaching the yield point during high earthquake motions, it functions as a damper (at this time, the movable bearing functions as the original movable bearing). As a result, it is possible to solve the various problems of the reaction force dispersion structure and the seismic isolation structure.

  By the way, the shear panel type vibration control stopper applied to the above-described bearing structure includes a base plate fixed to the lower structure, a pair of vertical flanges whose lower ends are welded to the base plate, and these flanges. And a shear panel (web) made of a low yield point steel provided vertically between them. The inventors of this application conducted repeated loading tests on such shear panel type vibration control stoppers, and found that the distortion of the welded portion between the flange and the base plate was large, and there was a problem with low cycle fatigue durability. I found.

  Further, the shear panel type vibration control stopper is provided with a stiffener at a position to be a loading point of the shear load. Since this stiffener is also fixed between the flanges by welding, it has been found that a relatively large strain occurs due to repeated loading in the welded part, although not as much as the welded part between the flange and the base plate.

The prior art information related to the invention of this application is an application example between the upper and lower structures, and is not related to the shear panel type vibration damping stopper itself, but includes the following.
Japanese Patent Laid-Open No. 10-77750

The present invention has been made based on the technical background as described above, and achieves the following object.
An object of the present invention is to provide a shear panel type vibration control stopper capable of reducing distortion at a welded portion between a flange and a base plate and improving low cycle fatigue durability.

  Another object of the present invention is to reduce the strain of the welded portion between the flange and the base plate, reduce the strain of the welded portion between the stiffener and the flange, and improve the low cycle fatigue durability. It is to provide a panel-type vibration control stopper.

The present invention employs the following means in order to achieve the above object.
That is, the first means according to the present invention includes a base plate, a pair of longitudinal flanges whose lower end portions are welded to the base plate, and a shear formed of a low yield point steel provided longitudinally between the flanges. A shear panel type vibration control stopper that is installed so as to restrain displacement of the upper structure between the upper structure and the lower structure.
The web has a shear panel-type seismic damping stopper characterized in that it has a lower constraining panel connected to the lower side of the shear panel and having a higher yield shear strength than the shear panel.

  The vibration control stopper includes a pair of stiffeners welded between the pair of flanges so as to sandwich an upper portion of the web, and the web includes an upper side of the shear panel in addition to the lower restraint panel. An upper constraining panel having a higher yield shear strength than the shear panel, and the stiffener is welded to the flange above the boundary between the shear panel and the upper constraining panel. It is also possible to adopt the configuration.

According to a second means of the present invention, there is provided a base plate, a pair of longitudinal flanges whose lower ends are welded to the base plate, and a shear formed of a low yield point steel provided longitudinally between the flanges. A shear panel type vibration control stopper that is installed so as to restrain displacement of the upper structure between the upper structure and the lower structure.
A shear panel-type damping stopper is characterized in that a rib is provided on the outer surface of the lower end of each flange.

  Also in the case of this second means, the shear panel-type damping stopper includes a pair of stiffeners welded between the pair of flanges so as to sandwich an upper portion of the web, An upper constraining panel having a yield strength greater than that of the shear panel continuously provided on the upper side of the shear panel, and the stiffener is disposed on the flange above the boundary between the shear panel and the upper constraining panel. A welded configuration can also be employed.

In the above-mentioned shear panel type damping stopper, it is desirable that the panel strength ratio Sy ₂ / Sy ₁ is 1.5 to 2.0 when the yield shear strength of the shear panel and the restraint panel is Sy ₁ and Sy ₂ , respectively. It is an aspect. In this case, in order to obtain the panel yield strength ratio, the constraining panel is made of the same material as the shear panel and has a larger thickness than the shear panel. Alternatively, in order to obtain the panel yield strength ratio, the constraining panel is made of a material having the same thickness as the shear panel and a yield shear stress larger than that of the shear panel.

  According to the first means of the present invention, since the web structure has the lower restraint panel on the lower side of the shear panel, the bending stress of the flange generated at the welded portion between the flange and the base plate is measured between the shear panel and the lower restraint panel. As a result, it is possible to improve the low cycle fatigue durability, which can reduce the distortion of the welded portion.

  In addition to the lower restraint panel, the web structure having the upper restraint panel on the upper side of the shear panel can also reduce the distortion of the welded portion between the stiffener and the flange.

  Further, according to the second means of the present invention, since the rib is provided on the outer surface of the lower end of the flange, the bending stress of the flange generated in the welded portion between the flange and the base plate can be dispersed in the rib. As a result, it is possible to improve the low cycle fatigue durability, which can reduce the distortion of the weld.

  Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show an embodiment of the present invention, FIG. 1 is a front view, FIG. 2 is a plan view, and FIG. 3 is a sectional view taken along line AA in FIG. A shear panel type vibration damping stopper 1 (hereinafter simply referred to as a vibration damping stopper) according to the present invention is installed in combination with a movable bearing (not shown) between an upper structure 2 and a lower structure 3 in a bridge, for example.

  The damping stopper 1 includes a base plate 4 fixed to the lower structure 3, a pair of flanges 5, 5 provided vertically on the base plate 4, and a web 6 provided vertically between the flanges 5, 5. And. A pair of stiffeners 7 and 7 are provided between the pair of flanges 5 and 5 so as to sandwich the upper portion of the web 6. The stiffeners 7 are members provided at a height position where the shearing force S is loaded.

  The base plate 4, the flanges 5, 5 and the stiffeners 7, 7 are all made of ordinary steel, and the lower ends of the flanges 5, 5 are welded to the base plate 4. Further, both ends of the stiffeners 7 and 7 are welded to the flanges 5 and 5.

  The web 6 has a shear panel 8 made of a low yield point steel, and further has a lower restraint panel 9 connected to the lower side of the shear panel 8. The lower restraint panel 9 is a member having a higher yield shear strength than the shear panel 8. That is, the web 6 is a hybrid panel composed of a shear panel 8 and a lower restraint panel 9 having different yield shear strengths. The end portions of the shear panel 8 and the lower restraint panel 9 are welded to each other, and the lower end portion of the lower restraint panel 9 is welded to the base plate 4.

  FIG. 4 is a front view showing another embodiment of the present invention. As described above, the stiffeners 7 and 7 are also welded to the flanges 5 and 5. In this embodiment, the web 6 has an upper restraint panel 10 connected to the upper side of the shear panel 8 in addition to the lower restraint panel 9. The stiffeners 7 and 7 are welded to the flanges 5 and 5 above the boundary between the shear panel 8 and the upper restraint panel 10. Similarly to the lower restraint panel 9, the upper restraint panel 10 is also a member having a higher yield shear strength than the shear panel 8.

In order to make the yield shear strength of each of the restraint panels 9 and 10 greater than that of the shear panel 8, one of the following methods can be selected.
(1) The restraint panels 9 and 10 are made of the same material as the shear panel 8 (low yield point steel), and the thickness is made larger than that of the shear panel 8.
(2) The thickness of the restraining panels 9 and 10 is the same as that of the shear panel 8, and the material is one whose yield shear stress is larger than that of the shear panel 8 (normal steel).
(3) Use the methods (1) and (2) above.

  As shown in FIGS. 1 and 4, for example, in a bridge, engaging portions (or upper structure side stoppers) 2 a and 2 a are provided at the lower portion of the upper structure 2, and the vibration damping stopper 1 is connected to the engaging portions 2 a and 2 a. Is installed in the lower structure 3 in a state of being engaged with the upper ends of the flanges 5 and 5. For this reason, the upper structure 2 cannot be displaced at all times or until level 1 earthquake motion, and the vibration control stopper 1 functions as a stopper that restrains the displacement of the upper structure 2.

  On the other hand, when the ground motion exceeds level 1, a repeated shear load S exceeding the yield shear strength of the shear panel 8 acts on the damping stopper 1. As a result, the shear panel 8 undergoes shear plastic deformation. At this time, the shear panel 8 has a hysteresis damping property, and thus absorbs the energy of earthquake motion. That is, the damping stopper 1 functions as a damper that attenuates vibration. Level 1 seismic motion refers to the seismic motion shown in “Road Bridge Specification (V Seismic Design) / Description” (Japan Road Association).

  FIG. 5 is a diagram for explaining the behavior when the damping stopper 1 undergoes shear deformation in comparison with the conventional one. In this figure, (a) shows a conventional vibration control stopper 50, and (b) shows the vibration control stopper 1 of the present invention shown as an embodiment in FIG. Needless to say, in the conventional vibration control stopper 50, the web 6 is composed only of the shear panel 8.

When the shearing force S is loaded on both the conventional damping stopper 50 and the damping control 1 of the present invention, the shearing force acts on the web 6 and is transmitted to the base plate 4. Here, the yield shear strength of the shear panel 8 is Sy ₁ and the yield shear strength of the restraining panels 9 and 10 is Sy ₂ (where Sy = D × t × τy, D: panel width, t: panel thickness, τy) : Shear yield stress of the panel), assuming that a shear force S of Sy ₁ <S <Sy ₂ acts on the web 6, the shear yield of the web 6 is the same with the conventional damping stopper 50 and the damping stopper 1 of the present invention. The range to do is different.

  That is, in the conventional vibration damping stopper 50, the entire web 6 below the stiffener 7 is shear yielded. For this reason, local bending deformation of the flanges 5 and 5 occurs in the welded portion A between the flanges 5 and 5 and the base plate 4, and a large strain occurs in the welded portion A. As a result, when repeated shear deformation with a large amount of displacement is applied, there is a risk of fracture at the weld zone a. Similarly, even in the welded portion B between the stiffener 7 and the flanges 5 and 5, local bending deformation of the flanges 5 and 5 occurs and distortion occurs, although not as much as the welded portion A.

  On the other hand, in the damping stopper 1 of the present invention, only the shear panel 8 yields a shear yield, and the restraint panels 9 and 10 do not reach the shear yield. For this reason, the bending deformation parts of the flanges 5 and 5 shift from the weakly welded parts A and B to the boundary parts C and D of the shear panel 8 and the restraining panels 9 and 10 which are materially strong. As a result, the distortion of the welded portions A and B can be reduced, and the fatigue durability of the flanges 5 and 5 can be improved.

Yield shear strength of shear panel Sy ₁ and yield shear strength of constrained panel Sy ₂ and panel strength ratio Sy ₂ / Sy ₁ were changed in various ways, and FEM analysis was attempted. did it. In Table 1, Case No. 0 is a conventional vibration control stopper. Cases No. 1 to No. 3 have the same thickness for the shear panel and the restraint panel, and the restraint panel uses ordinary steel. Cases No. 4 to No. 6 have the same low yield point for the shear panel and the restraint panel. Steel is used and the thickness is changed.

  “Welding section strain” is the strain of the welded portion of the flange and the base plate (a in FIG. 5). . “Weld zone strain ratio” and “Boundary zone strain ratio” indicate the ratio when the weld zone strain generated in the conventional vibration control stopper (case No. 0) is 1.00.

According to the analysis results, if the panel strength ratio Sy ₂ / Sy ₁ is too small, the weld distortion is not reduced much (Case No. 1). Conversely, if the panel strength ratio Sy ₂ / Sy ₁ is too large, the weld strain will be greatly reduced, but the strain at the boundary will be too great and the burden on the border will be increased (cases No. 3 and No. 6). In either case, the weld strain and boundary strain cannot be balanced. On the other hand, when the panel strength ratio Sy ₂ / Sy _{1 is set} to 1.5 to 2.0, the weld strain is reduced (the weld strain ratio is 0.2 or less) and the increase in the boundary strain can be suppressed (in the boundary strain ratio). It was found that the balance between the two was achieved (Case No.2, No.4, No.5). Therefore, in order to improve the fatigue durability of the flanges 5 and 5, it is the most preferable aspect to select the panel yield strength ratio from the above numerical range.

  That is, when using low yield point steel of the same material for the shear panel and restraint panel, the thickness of the restraint panel is 1.5 to 2.0 times that of the shear panel. If the shear panel and the restraint panel have the same thickness, select a restraint panel steel material whose yield shear stress is 1.5 to 2.0 times that of the shear panel. The above analysis results relate to the welded portion between the flange and the base plate, but it is presumed that similar results can be obtained for the welded portion between the flange and the stiffener.

  The embodiment shown in FIGS. 1 to 4 is an example in which a restraint panel is provided as a means for reducing the distortion of the welded portion between the flange and the base plate. However, the distortion of the welded portion can be reduced by means other than this. Can be reduced. 6 and 7 show the embodiment, FIG. 6 is a front view, and FIG. 7 is a plan view.

  In this embodiment, the damping stopper 1 is provided with ribs 11 on the outer surfaces of the lower ends of the flanges 5 and 5. The rib 11 is formed with an arcuate fillet 12 and is provided in the same plane as the web 6, that is, the shear panel 8. The rib 11 is welded to the flanges 5 and 5 and the lower end is welded to the base plate 4. By providing such a rib 11, bending stress generated in the welded portion between the flanges 5, 5 and the base plate 4 is dispersed in the rib 11, and distortion of the welded portion can be reduced.

  FIG. 8 is a front view showing still another embodiment. In this embodiment, the upper restraining panel 10 is continuously provided on the upper side of the shear panel 8 in the vibration damping stopper 1 provided with the ribs 11 as in the embodiment shown in FIG. Therefore, the stiffener 7 is welded to the flanges 5 and 5 above the boundary between the shear panel 8 and the upper restraint panel 10. As described above, the distortion of the welded portion between the stiffener 7 and the flange 5 can be reduced by installing the upper restraint panel 10.

  The damping stopper according to the present invention is not limited to being installed between the upper and lower structures of the bridge. For example, Patent Document 1 describes that a damper is installed in combination with an isolator between a building (upper structure) and a foundation (lower structure), but it can also be applied as such a damper. It is. In this case, as described in the same document, the installation mode is such that displacement of the upper structure within a predetermined range is allowed and the upper structure is restrained against further displacement. Moreover, the aspect which attaches to a superstructure instead of a lower structure can also be taken for a damping stopper.

It is a front view which shows embodiment of this invention. It is a top view of the embodiment. It is AA arrow sectional drawing of FIG. It is a front view which shows another embodiment. It is a figure which compares and demonstrates the behavior of the vibration control stopper of this invention and the conventional one. It is a front view which shows another embodiment. It is a top view of the embodiment. It is a front view which shows another embodiment.

Explanation of symbols

1 Shear panel type vibration control stopper
2 Upper structure 2a, 2a Engagement part 3 Lower structure 4 Base plate 5 Flange 6 Web 7 Stiffener 8 Shear panel 9 Lower restraint panel 10 Upper restraint panel 11 Rib 12 Fillet

Claims (7)

A superstructure comprising a base plate, a pair of longitudinal flanges welded to the base plate at the lower end, and a web having a shear panel made of low-yield point steel provided longitudinally between the flanges; A shear panel type damping stopper installed to restrain the displacement of the upper structure between the lower structure and
The shear panel type vibration control stopper, wherein the web has a lower constraining panel connected to the lower side of the shear panel and having a higher yield shear strength than the shear panel. A pair of stiffeners welded between the pair of flanges to sandwich the top of the web;
The web has an upper restraint panel connected to the upper side of the shear panel and having a higher yield shear strength than the shear panel;
The shear panel type vibration control stopper according to claim 1, wherein the stiffener is welded to the flange above a boundary portion between the shear panel and the upper restraint panel. A superstructure comprising a base plate, a pair of longitudinal flanges welded to the base plate at the lower end, and a web having a shear panel made of low-yield point steel provided longitudinally between the flanges; A shear panel type damping stopper installed to restrain the displacement of the upper structure between the lower structure and
A shear panel type vibration control stopper, characterized in that a rib is provided on the outer surface of the lower end of each flange. A pair of stiffeners welded between the pair of flanges to sandwich the top of the web;
The web has an upper restraint panel having a higher yield shear strength than the shear panel connected to the upper side of the shear panel;
4. The shear panel type vibration control stopper according to claim 3, wherein the stiffener is welded to the flange above the boundary between the shear panel and the upper restraint panel. 5. The panel yield strength ratio Sy ₂ / Sy ₁ is 1.5 to 2.0 when the yield shear strengths of the shear panel and the restraint panel are Sy ₁ and Sy ₂ , respectively. Shear panel type vibration control stopper.   6. The shear panel type vibration control stopper according to claim 5, wherein the constraining panel is made of the same material as the shear panel and has a thickness larger than that of the shear panel in order to obtain the panel yield strength ratio. .   6. The shear panel according to claim 5, wherein the constraining panel is made of a material having the same thickness as the shear panel and a yield shear stress larger than that of the shear panel in order to obtain the panel yield strength ratio. Type damping stopper.

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