JP4466401B2 - Laminated rubber support - Google Patents

Description

  The present invention relates to a structure in which a tensile force can act in the axial direction and a laminated rubber bearing used in a specific part in the structure.

Laminated rubber, which is most commonly used as a seismic isolation device for buildings and bridges, exhibits high strength against axial compressive force, but has extremely low strength against tensile force, so it is integrated with laminated rubber. The laminated rubber bearing including the flange is designed so as not to generate a tensile force on the laminated rubber, that is, the variable axial force due to an earthquake or the like does not exceed the normal long-term vertical axial force.

However, because of the large tower ratio (the ratio of the height to the width of the building) or due to the planar shape of the building itself, the building will generate a large tensile force in the vertical direction due to the horizontal vibration of the building. In addition to the laminated rubber used, laminated rubber installed immediately below the multi-layer earthquake resistant wall inevitably generates an excessive tensile force in the axial direction, which may damage the laminated rubber, such as breaking.

In such a case, by providing a gap of about several tens of millimeters between the head of the bolt that joins the upper flange of the laminated rubber bearing to the upper base plate fixed to the lower surface of the upper structure and the lower surface of the upper flange. There is a method that allows the upper structure to lift up the gap and does not apply a tensile force to the laminated rubber (see Non-Patent Document 1). In this case, a groove is formed on the lower surface of the upper base plate so that the upper flange and the upper base plate are horizontally locked even when the gap is lifted, and shear force is transmitted between the two. The upper flange is inserted.

In addition, the laminated rubber constituting the seismic isolation device is separated into upper and lower parts, steel plates are joined to the end faces of both separated laminated rubbers, and a shear key is horizontally interposed between the two steel plates. A method in which a horizontal force is transmitted between separated laminated rubbers by not joining them, and a displacement in a direction in which the separated laminated rubbers are separated from each other is allowed, and a tensile force is not applied to the laminated rubber (see Patent Document 1), flange A method in which the thickness of the portion other than the portion overlapping the laminated rubber is made smaller than the thickness of the portion overlapping the laminated rubber, and the deformation is concentrated on the portion other than the portion overlapping the laminated rubber so that the tensile force is not applied to the laminated rubber. (See Patent Document 2).
"MENSHIN NO. 38 2002/11", Japan Seismic Isolation Structure Association, November 2002, No. 38, p. 12-13 Japanese Patent Laid-Open No. 10-317715 JP 2002-195327 A

The method of Non-Patent Document 1 only allows the lifting of the upper structure of about several tens of millimeters. If the lifting exceeds the allowable amount, the upper flange comes into contact with the upper base plate, and then the laminated rubber is used instead. Therefore, since there is no element that can resist the tensile force, an axial tensile force is applied to the laminated rubber, and the laminated rubber is damaged.

Increasing the lift allowance increases the thickness of the upper base plate and upper flange and requires longer bolts, but also increases the height of the space between the lower structure and the upper structure. If there is not enough room, the seismic isolation device cannot be installed, and the amount of protrusion of the bolt from the lower surface of the upper flange also increases, so there is a high possibility that the laminated rubber will collide with the bolt during shear deformation of the laminated rubber. Become.

The method of Patent Document 1 allows the lifting of the upper structure within a range in which the state in which the steel plate and the shear key are locked can be maintained.
The shear key is detached from the steel plate and the laminated rubber cannot function.

In addition, since steel plates and shear keys cannot resist the tensile force at the time of lifting, in order to cause shear deformation in laminated rubber separated vertically when an axial tensile force acts on the seismic isolation device, It is necessary to maintain the state where the shear key is always locked, and if it is intended to increase the allowable floating amount, it is necessary to increase the height of the shear key as in Non-Patent Document 1, so the lower structure and the upper structure If the space between them is not high enough, it cannot be installed.

In the method of Patent Document 2, since the flange consisting of a portion other than the portion overlapping the laminated rubber and the portion overlapping the laminated rubber is a continuous plate, when bending deformation occurs in the thin portion as the upper structure is lifted In addition, there is a possibility that the portion overlapping the laminated rubber may also be deformed. In addition, since the horizontal force generated in the laminated rubber body must be transmitted safely, there is a limit to making the flange thin, and with this limit, a significant improvement in tensile deformation capacity cannot be expected.

  In order to solve the above-mentioned problems, the applicant of the present invention has proposed a laminated rubber bearing that suppresses the action of the tensile force on the laminated rubber that accompanies the lifting while ensuring a sufficient lifting allowance of the superstructure and a resistance to the lifting. (Japanese Patent Application No. 2003-295011).

  FIG. 8 shows an example of a laminated rubber support of the winged steel plate type (wing plate) in the above invention. The laminated rubber support 1 is integrally formed with the laminated rubber 2 and above and below the laminated rubber 2. The upper and lower flanges 3 and 4 are provided, and a plurality of flat-type winged steel plates 5 are arranged around the lower flange 4 at intervals in the circumferential direction. The upper flange 3 is directly fixed to the upper structure 6, while the lower flange 4 is fixed to the lower structure 7 via a plurality of winged steel plates 5, so that a laminated rubber body when a tensile force is generated in the laminated rubber 2 in the event of a large earthquake. This prevents damage.

  That is, as shown in FIG. 8A, the normal compression axial force is transmitted from the lower flange 4 of the laminated rubber 2 to the lower structure 7. On the other hand, as shown in FIG. 8B, when a large tensile deformation occurs during a large earthquake, most of the tensile deformation is absorbed by the elastic deformation or elasto-plastic out-of-plane bending deformation of the winged steel sheet 5, and the laminated rubber main body is absorbed. Is intended to prevent excessive tensile deformation and tensile stress. The winged steel plate is bolted to the lower flange 4 and the lower structure 7 so that they can be easily replaced.

  However, when a large vertical lift occurs, the winged steel plate 5 undergoes a geometric elongation deformation ΔL as shown in FIG. 8C, and thus a large axial force is generated. Since this in-plane axial force is inclined because the winged steel plate 5 is lifted, a part of the axial force acts on the laminated rubber 2 as a tensile force, and the tensile axial force acting on the laminated rubber which is the object of the present invention is reduced. Is not preferred.

  The present invention has been made to solve the above-mentioned problems, and while ensuring a sufficient allowance for lifting of the superstructure in the laminated rubber bearing and resistance to lifting, the action of tensile force on the laminated rubber accompanying lifting Proposed laminated rubber bearing that can reduce the tensile force acting on laminated rubber and obtain higher performance laminated steel bearing of winged steel sheet type. It is.

The invention according to claim 1 of the present invention is a laminated rubber bearing comprising a laminated rubber and flanges integrally provided on the upper and lower sides thereof and respectively joined to the upper structure and the lower structure. Around one of the flanges, there is provided a fixing plate for fixing the flange to either the upper structure or the lower structure so that the upper structure can be lifted with respect to the lower structure. Is provided with a deformable portion that can be extended and deformed by an in-plane axial force acting on the fixing plate when the substructure is lifted with respect to the lower structure (for example, when a large vertical lift is generated in the laminated rubber bearing). It is a featured laminated rubber bearing. The deformable portion may be any shape that can be extended and deformed by the in-plane axial force of the fixed plate, and various shapes and structures can be used.

  The invention according to claim 2 of the present invention is the laminated rubber bearing according to claim 1, wherein the deformed portion is formed by raising the joint end portions of the flange-side portion and the non-flange-side portion of the divided fixing plate. It is a laminated rubber bearing characterized by being a connecting portion formed by joining with bolts. For example, as shown in FIG. 1 (a), the fixing plate is a folded and connected blade-type steel plate, and the steel plate is divided into a flange side portion and an anti-flange side portion, and the flange side portion and the anti-flange side portion. It is preferable to form a rising portion by bending each of the joining end portions at right angles, overlapping the rising portions, sandwiching them from both sides with a pressing plate, and joining them with bolts. In this deformation part, it bends and deforms so that a pair of rising parts open with respect to the in-plane axial force of the fixed plate.

  The invention according to claim 3 of the present invention is the laminated rubber bearing according to claim 1, wherein the deformed portion is a bent portion formed into a corrugated shape protruding out of the plane of the fixed plate. Laminated rubber bearing. For example, as shown in FIG. 1 (b), the fixed plate is an integral folding type winged steel plate, and the steel plate is bent out of plane into a corrugated shape to form an integrated bent portion. An integrated type in which the curved portion is a deformable portion may be used. Also in this case, it bends and deforms so that the pair of rising portions open.

  The present invention does not directly fix the flange of the laminated rubber to the upper structure or the lower structure, but fixes it through a fixing plate such as a winged steel plate protruding from the outer periphery of the flange. In the winged steel plate type laminated rubber bearing that prevents the damage of the laminated rubber body due to the tensile force by suppressing the action of the tensile force on the laminated rubber due to lifting while securing the resistance to To a deformed type (e.g., a bending connection type, an integrated folding type) having an extended deformation portion.

  When a large vertical lift occurs in the laminated rubber bearing, the winged steel plate undergoes geometrical elongation and deformation, and in the case of the flat plate type, the large axial force in the plane is inclined because the winged steel plate is lifted. The part acts as a tensile force on the laminated rubber. On the other hand, in the present invention, a deformed portion that stretches and deforms is formed on a fixed plate such as a winged steel plate, and this deformed portion causes stretch deformation. Therefore, the rigidity against the in-plane axial force is low compared to the flat plate type, and the same With respect to elongation deformation, only a small in-plane axial force is generated in the deformation type fixing plate, and the tensile force generated in the laminated rubber is smaller than that in the flat plate type, and a higher performance laminated rubber bearing can be obtained.

  A plurality of fixing plates are arranged around the flange at equal intervals in the circumferential direction. The deformed portion is preferably provided at the center position because a large out-of-plane bending moment is generated at the end portion of the fixing plate, and the stress state becomes complicated and damage may be concentrated.

  Further, it is preferable that the flange-side end portion and the non-flange-side end portion of the fixing plate are separably joined to the outer peripheral portion of the flange, the lower structure or the upper structure with a bolt or the like so that they can be easily exchanged.

  In the present invention, since a fixed portion such as a winged steel plate disposed around the flange of the winged steel plate type laminated rubber support is provided with a deformable portion that can be extended and deformed by an in-plane axial force, the fixed plate such as the winged steel plate is used. It is possible to prevent the damage of the laminated rubber body due to the tensile force by suppressing the action of the tensile force on the laminated rubber due to the lifting while ensuring the sufficient lifting allowance of the superstructure and the resistance to lifting. In addition, by adopting a deformation type having a deformable portion that stretches and deforms, the deformed portion causes stretch deformation. Therefore, the rigidity with respect to the in-plane axial force is lower than that of the flat plate type. Deformation type with deformed part produces only a small in-plane axial force, and the tensile force generated in laminated rubber is smaller than that of flat plate type. Rukoto can.

  Further, in the flat plate type, in order to alleviate the influence of the geometric elongation deformation with respect to the same amount of vertical tensile deformation, the length L (see FIG. 5) of the fixed plate such as the winged steel plate is increased to increase the geometrical length. It is possible to reduce the tensile strain generated in the laminated rubber bearing by reducing the elastic elongation strain, but the width B and the thickness t (see FIG. 5) are also increased by ensuring the in-plane rigidity and proof stress as the length increases. I have to be. This is not limited to the cost increase of the fixing plate, but the installation space is not compact. However, the deformation type having the deformation portion of the present invention can be installed in a compact manner and has the effect of reducing the cost.

  This embodiment is an example of a laminated rubber bearing using a winged steel plate (wing plate) as a fixed plate. FIG. 1 is an example of a laminated rubber support according to the present invention, and is an elevational sectional view showing a case of a deformed type winged steel plate such as a bent connection type. FIG. 2 is a plan view showing a planar arrangement example of the winged steel plate of the laminated rubber support of FIG. FIG. 3 and FIG. 4 show an example of a bent connection type winged steel sheet and a method for manufacturing the same.

  In the embodiment of FIG. 1, the laminated rubber support 1 includes a laminated rubber 2, upper and lower flanges 3, 4 integrally provided above and below the laminated rubber 2, and a circumferential interval around the lower flange 4. It is comprised from the winged steel plate 10 of deformation | transformation types, such as a bending connection type etc. arrange | positioned in multiple numbers. Similar to the flat plate type, the upper flange 3 is directly fixed to the upper structure 6 with bolts 8, and the lower flange 4 is fixed to the lower structure 7 via a plurality of winged steel plates 10. This prevents the laminated rubber body from being damaged.

  As shown in FIG. 1 (a), the folded connection type winged steel plate 10 connects two steel plates 10a divided as will be described in detail later by connecting them at a rising connection portion 12 by bending, and this rising connection portion. 1 is a split connection type having an elongated deformed portion. As shown in FIG. 1 (b), the steel plate 10 is bent into a corrugated shape out of the plane to form an integrated bent portion 12 '. An integral bending type in which the curved portion 12 ′ is an elongated deformable portion may be used. In addition, various deformation | transformation parts in which expansion deformation is possible are considered. The following is a case of the winged steel plate 10 of the bent connection type of FIG.

  As shown in FIG. 2, the blade-shaped steel plate 10 has a substantially quadrangular planar shape, and a plurality of the blade-shaped steel plates 10 are arranged around the lower flange 4 at equal intervals in the circumferential direction. One end of the winged steel plate 10 is joined to the upper surface of the outer periphery of the lower flange 4 with a bolt 9, and the other end is joined to the upper surface of the lower structure 7 with a bolt 9, so that it can be easily replaced.

  As shown in FIG. 3, the winged steel plate 10 of the bent connection type uses two steel plates 10a divided into two parts, a flange side part and an anti-flange side part, and the joint end part is bent at a right angle to rise. By forming the portion 10 b, the rising portions 10 b are overlapped with each other and joined with the bolt 11, the rising connecting portion 12 is formed at the center position of the winged steel plate 10. Such a rising connecting portion 12 is configured such that the rising portion 10b is bent and deformed with respect to the in-plane axial force to reduce the rigidity against the in-plane axial force. The reason why the rising connecting portion 12 is provided at the center position is that a large out-of-plane bending moment is generated at the end portion, so that the stress state becomes complicated and concentration of damage may occur. Moreover, as shown in FIG. 2, it is preferable to provide the taper (r) 10c in the both sides of the steel plate 10a toward the bolt junction. This is because edge stress due to in-plane bending concentrates in addition to in-plane axial force and large out-of-plane bending plastic deformation.

  Further, it is preferable that the bolt joining portion of the rising portion 10 b is attached with a pressing plate 13, and the stacked rising portions 10 b are sandwiched from both sides by a pair of pressing plates 13 and firmly joined by a large number of bolts 11. Similarly, the pressing plate 14 is also used for the bolt joints at both ends of the winged steel plate 10. In addition, although the rising connection part 12 of the example of illustration is upward, when it interferes with the laminated rubber which the short-term compression axial force acted on, it can also be made downward.

  As a manufacturing method of the winged steel plate 10 of the bending connection type, a method of bending a steel plate by cold press, a method of joining steel plates by butt welding (see FIG. 4 (a)), a cold-formed square steel pipe There is a cutting method (see FIG. 4B).

  Next, FIG. 5 to FIG. 7 show examples in which a conventional flat plate type and the bent connection type of the present invention are compared. In FIG. 5, the steel plates are SS material, SM material, SN material, and others, and the mounting bolts are high strength bolts, medium bolts, and the like. In addition, the stipulations of the winged steel sheet are such that the length of the connecting portion L ≧ 300 mm, the width (holding plate portion) B ≧ 0.5 × L, the thickness t = 6 to 32 L, the height H ≦ L / 4, t ≦ the bending radius. R (internal method) ≦ 3.0 × t or the like. The taper radius Rp is about 10 to 30 mm.

  When such a winged steel plate is subjected to a tensile vertical load as shown in FIG. 5 (c), a geometric elongation deformation ΔL occurs, and the distribution of the in-plane axial force N and the out-of-plane bending moment M is shown in FIG. ) As shown. In the case of the bending connection type, the rising portion steel plate of the central connection portion is bent and deformed as shown in FIG. 5E, and the bending moment distribution (when elastic) with the in-plane axial force N is shown in FIG. It will be shown in When the geometrical elongation deformation progresses beyond the yield axial force, the central connecting portion is lowered as shown in FIG. 6 (b). Therefore, in consideration of the fall amount S, the bending moment associated with the in-plane axial force N is considered. The distribution (after plasticization) is as shown in FIG.

  When the axial force N in the plane of the winged steel sheet is determined in consideration of the above, the relationship between the geometric elongation amount ΔL and the axial force N in the plane of the winged steel sheet is as shown in FIG. In the case of the bending connection type, the axial elastic stiffness with respect to the in-plane axial force is smaller than that of the flat plate type due to bending deformation, and the in-plane axial force N generated in the winged steel plate is smaller than that of the flat plate type.

  FIG. 7 is an example of calculation of tensile vertical characteristics by a simple evaluation method. In the case of a bending connection type, the in-plane axial force N becomes smaller than that of a flat plate type (FIG. 7 (d)). The rubber tensile surface pressure is smaller than that of the flat plate type (FIGS. 7A and 7B). The end surface out-of-plane bending moment is larger than that of the flat plate type (FIG. 7C).

  Note that the present invention is not limited to the above-described embodiment, and other various aspects can be adopted.

BRIEF DESCRIPTION OF THE DRAWINGS It is an example of the laminated rubber bearing of this invention, (a) is an elevational sectional view which shows the case of a bending connection type winged steel plate, (b) is an elevational section which shows the case where an elongation deformation part is an integral bending part. FIG. It is a top view which shows the example of plane arrangement | positioning of the winged steel plate of the laminated rubber support of FIG. It is an elevation view which shows the bending connection type winged steel plate of this invention. It is an elevation view of the manufacturing method of the bending connection type winged steel plate of the present invention. It compares the conventional flat plate type of a wing plate steel plate and the connection type of the present invention, (a) is a plan view of the wing plate steel plate, (b) is an elevation view of the wing plate steel plate, and (c) shows a deformation state. Elevation view, (d) is a graph showing the stress / bending moment distribution, and (e) is an elevation view showing the moment distribution of the connecting portion. It is a connection type of the present invention, (a) is an elevation showing the bending moment distribution at the time of elasticity, (b) is an elevation showing the deformation state, (c) is a elevation showing the bending moment distribution after plasticization. FIG. 4D is a graph comparing the relationship between ΔL and N for a flat plate type and a connection type. It is a graph which shows the relationship of the vertical tensile force with respect to a vertical tensile deformation, laminated rubber tension surface pressure, an end surface out-of-plane bending moment, and a wing-shaped steel plate in-plane axial force. It is an elevation which shows the laminated rubber bearing which has the conventional flat plate type winged steel plate, (a) is a normal state, (b) is the state which received the tensile deformation, (c) is the amount of tensile deformation of a winged steel plate. Show.

Explanation of symbols

1 …… Laminated rubber bearing 2 …… Laminated rubber 3 …… Upper flange 4 …… Lower flange 5 …… Foiled steel plate (flat plate type)
6 …… Superstructure 7 …… Substructure,
8 ... Bolt 9 ... Bolt 10 ... Boiled steel plate (fixing plate for connection type, etc.)
DESCRIPTION OF SYMBOLS 10a ... Steel plate 10b ... Rising part 10c ... Taper 11 ... Bolt 12 ... Rising connection part 12 '... Bending part 13 ... Holding plate 14 ... Holding plate

Claims (4)

In laminated rubber bearings consisting of laminated rubber and flanges that are integrally provided above and below and joined to the upper structure and the lower structure,
Around the flange of at least one of the upper and lower flanges, there is provided a fixing plate for fixing the flange to either the upper structure or the lower structure so that the upper structure can be lifted with respect to the lower structure . A laminated rubber bearing , wherein the fixed plate is provided with a deformable portion that can be extended and deformed by an in-plane axial force acting on the fixed plate when the upper structure is lifted relative to the lower structure . Deformations, according to claim 1, characterized in that the joint end portions of the divided flange portion and the anti-flange side portion of the fixed plate superimposed launching each a connecting portion formed by joining with bolts laminated rubber bearing of. The laminated rubber bearing according to claim 1, wherein the deformable portion is a bent portion formed in a corrugated shape protruding out of the surface of the fixed plate. The laminated rubber bearing according to any one of claims 1 to 3, wherein the deforming portion of the fixing plate can be plastically deformed after elongation deformation.

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