JP7171389B2 - Inspection method for laminated rubber bearings - Google Patents

Description

The present invention relates to an in-situ inspection method for laminated rubber bearings used in bridges, buildings and the like.

Laminated rubber bearings are installed between the lower and upper structures of bridges and buildings to support the upper structure. Laminated rubber bearings containing lead plugs are known which are arranged through columnar lead plugs.

Laminated rubber bearings support the superstructures of bridges and buildings by means of laminates, and when an earthquake occurs, they deform horizontally to move the superstructures, and restore the displaced superstructures to their original positions. It has the function of lengthening the period and reducing the seismic force acting on the superstructure. In addition to the function of the laminated rubber bearing, the laminated rubber bearing containing lead plugs has a damper function of absorbing vibration energy and attenuating the shaking of the upper structure due to the lead plug.

The above laminated rubber bearings and laminated rubber bearings containing lead plugs undergo various deterioration and damage over time after they are installed in bridges and buildings. Deterioration of the laminated rubber bearing over time includes peeling of the rubber and the steel plate of the laminated body, peeling of the coating rubber covering the side surface of the laminated body, ozone deterioration, and the like. Such deterioration over time leads to a decrease in restoring force during an earthquake and a decrease in the effect of reducing seismic force. Further, aging deterioration of the laminated rubber bearing containing a lead plug includes damage to the lead plug in addition to deterioration occurring in the laminated rubber bearing. Damage to the lead plugs causes deterioration of the damper function, which greatly affects the performance of the lead plug-containing laminated rubber bearing.

It is known that the forms of damage that occur in lead plugs over time are cracks, fractures, and flow projections, in descending order of damage. Flow protrusion is a phenomenon that occurs when the lead that forms the lead plug flows between the rubber and the steel plate of the laminate and is pushed out from the side surface. is thought to be caused by The damper function of lead plugs in laminated rubber bearings with lead plugs that have cracked, broken, or flowed out has significantly deteriorated and must be replaced immediately.

Before flow protrusion occurs in the laminated rubber bearing with lead plugs, deformation of the lead plugs such as lead flow, cracking, and breakage occurs inside the laminate, and the damper function of the lead plugs has already deteriorated. Progressively, the deterioration of the performance of laminated rubber bearings containing lead plugs has occurred. However, since the deformation of the lead plug that occurs inside the laminate cannot be detected from the appearance, it is not possible to detect the deterioration of the performance of the lead plug-containing laminated rubber bearing until the flow protrusion occurs. Therefore, in order to detect deterioration of the performance of laminated rubber bearings containing lead plugs at an early stage, there is a need for a non-destructive inspection method for deformation of lead plugs in laminated bodies.

Conventionally, as a method for non-destructively inspecting a lead plug installed inside a laminate, an inspection method for confirming the soundness of the lead plug using an X-ray CT apparatus has been proposed (see Patent Document 1). In this inspection method, in the manufacturing process of laminated rubber bearings containing lead plugs, tomography is performed in a non-destructive state using an X-ray CT device while the laminate is horizontally displaced while a vertical load is applied. . From the tomographic image of the laminate thus obtained, the state of the interface between the lead plug and the laminated rubber is confirmed, and the soundness of the lead plug is confirmed.

Japanese Patent Application Laid-Open No. 2001-033402

However, the above-described conventional lead plug inspection method is performed in the manufacturing process of laminated rubber bearings containing lead plugs, and uses a large-scale X-ray CT device. It cannot be applied to laminated rubber bearings with plugs. In addition, in the above-described conventional lead plug inspection method, it is necessary to take an image while displacing the laminate in the horizontal direction. Therefore, it is difficult to apply the above conventional method.

In addition, the above-described conventional lead plug inspection method is for checking the state of the interface between the lead plug and the laminated rubber, and cannot be applied to a laminated rubber bearing that does not have a lead plug in the laminated body of rubber and steel plate.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for inspecting laminated rubber bearings installed on bridges, buildings, etc., which can be inspected in situ regardless of the presence or absence of metal plugs. .

In order to solve the above-mentioned problems, a method for inspecting a laminated rubber bearing according to the present invention comprises: a laminate obtained by alternately laminating a plurality of plate-like rubbers and steel plates; A method for inspecting a laminated rubber bearing comprising a connection body connected to a structure through
In the original position where the laminated rubber bearing is installed, the laminate is irradiated with X-rays to obtain an X-ray image, and based on the gaps appearing in the laminate in the X-ray image, the laminate It is characterized by determining the degree of damage to the rubber bearing.

According to the above configuration, when the laminated rubber bearing is installed, for example, between the lower structure and the upper structure of a bridge, the connecting body on one side of the laminated body and the connecting body on the other side are connected to the lower structure and the superstructure. , respectively. Therefore, the inside of the laminate cannot be visually inspected at the original position where the laminated rubber bearing is installed. Here, in the method for inspecting a laminated rubber bearing of the present invention, an X-ray image is acquired by irradiating the laminate with X-rays at the original position where the laminated rubber bearing is installed. There is no need to remove the laminated rubber bearing and transport it to the X-ray CT apparatus as in the inspection method used. In addition, unlike the conventional inspection method using an X-ray CT device, there is no need to deform the laminated rubber bearing. Applicable. By using the X-ray image obtained in situ in this way, it is possible to inspect the inside of the laminate, which was not possible depending on the appearance of the laminate.

Further, according to the above configuration, the degree of damage to the bearing is determined based on the voids appearing in the laminate in the radiographic image. The voids that appear in the laminated body of the laminated rubber bearing are caused by the breakage of the adhesion between the plate-shaped rubber and the steel plate caused by the displacement of the laminated body, the breakage of the plate-shaped rubber, and the like. Further, when metal plugs are provided in the laminate, voids are generated in the laminate due to deformation of the metal plugs as well as breakage of adhesion between the rubber plate and the steel plate, breakage of the rubber plate. Therefore, the degree of damage to the laminated rubber bearing can be easily and effectively determined based on the voids appearing in the laminated body in the radiographic image. Here, the present invention can also be applied to a laminated rubber bearing in which a metal plug is provided inside the laminate.

The laminated rubber bearings include those installed in civil engineering structures such as bridges, those installed in architectural structures such as buildings, and those installed in plant equipment in various factories.

In one embodiment of the method for inspecting a laminated rubber bearing, the voids appearing in the laminate in the X-ray image reflect the voids existing between the plate-like rubber and the steel plate.

According to the above embodiment, deformation of the laminated rubber bearing breaks the adhesion between the plate-like rubber and the steel plate of the laminate, forming a gap between the plate-like rubber and the steel plate. There is Therefore, by searching for voids in the laminate in the X-ray photographed image, it is possible to discover failure of the adhesion between the plate-like rubber of the laminate and the steel plate, and easily determine the degree of damage to the laminated rubber bearing.

In one embodiment of the method for inspecting a laminated rubber bearing, the voids appearing in the laminate in the radiographic image are mirrored voids existing in the plate-like rubber.

According to the above-described embodiment, deformation of the laminated rubber bearing may damage the plate-like rubber of the laminate, forming a gap in the plate-like rubber. Therefore, by searching for voids in the laminate in the radiographic image, it is possible to discover damage to the plate-like rubber of the laminate and easily determine the degree of damage to the laminated rubber bearing.

In the method for inspecting a laminated rubber bearing of one embodiment, when there is no void in the laminated body in the radiographic image, the damage degree of the laminated rubber bearing is determined to be zero, and If there is a gap in the laminate, the degree of damage to the laminate rubber bearing is determined to be large.

According to the above embodiment, voids appearing in the laminate are caused by failure of adhesion between the rubber plate and the steel plate, failure of the rubber plate, etc. have a significant negative impact on the performance of Therefore, if there are no gaps in the laminate in the X-ray image, the degree of damage to the laminated rubber bearing is determined to be zero, and if there are gaps in the laminate in the X-ray image, the degree of damage to the laminated rubber bearing is is determined to be large, the soundness of the laminated rubber bearing can be appropriately evaluated.

A method for inspecting a laminated rubber bearing according to another aspect of the present invention includes a laminated body in which a plurality of plate-shaped rubbers and steel plates are alternately laminated, and a structure arranged on one side and the other side of the laminated body. A method for inspecting a laminated rubber bearing comprising: a connecting body connected to a connecting body; and a metal plug having a damper function and extending in a lamination direction of the plate-like rubber and the steel plate through the laminated body and the connecting body. ,
At the original position where the laminated rubber bearing is installed, the laminate is irradiated with X-rays to obtain an X-ray image, and the amount of deformation of the deformed portion of the metal plug in the X-ray image and the amount of deformation of the metal plug in the X-ray image. The degree of damage to the bearing is determined based on the distance between the tip of the deformed portion of the plug and the side surface of the laminate.

According to the above configuration, when the laminated rubber bearing is installed, for example, between the lower structure and the upper structure of a bridge, the connecting body on one side of the laminated body and the connecting body on the other side are connected to the lower structure and the superstructure. , respectively. Therefore, the inside of the laminate cannot be visually inspected at the original position where the laminated rubber bearing is installed. Here, in the method for inspecting a laminated rubber bearing of the present invention, an X-ray image is acquired by irradiating the laminate with X-rays at the original position where the laminated rubber bearing is installed. There is no need to remove the laminated rubber bearing and transport it to the X-ray CT apparatus as in the inspection method used. In addition, unlike the conventional inspection method using an X-ray CT device, there is no need to deform the laminated rubber bearing. Applicable. By using the X-ray image obtained in situ in this way, it is possible to inspect the inside of the laminate, which was not possible depending on the appearance of the laminate.

Further, in the laminated rubber bearing, a laminated body having a metal plug provided inside deforms the metal plug as the laminated body is deformed. Therefore, since the damage to the laminate often occurs from the metal plug and progresses, the distance between the tip of the deformed portion with respect to the metal plug and the side surface of the laminate is related to the degree of damage to the laminate. have a nature. Therefore, based on the deformation amount of the deformed portion related to the metal plug in the radiographic image and the distance between the tip of the deformed portion related to the metal plug and the side surface of the laminate, the damage degree of the laminated rubber bearing can be determined easily and appropriately. Here, the deformed portion of the metal plug refers to the deformed portion of the metal plug when only the metal plug is deformed. On the other hand, when the portion of the laminate in contact with the metal plug is deformed together with the metal plug, the deformed portion is the combined portion of the deformed portion of the metal plug and the deformed portion of the portion of the laminate in contact with the metal plug.

Here, examples of the metal plug having a damper function include those made of lead, tin, etc., but other metals may be used as long as they have a damper function.

In one embodiment of the method for inspecting a laminated rubber bearing, the amount of deformation of the deformed portion of the metal plug is 0.25 _Dp or more, where _Dp is the initial diameter of the metal plug in the radiographic image, and , the distance between the tip of the deformed portion of the metal plug and the side surface of the laminate is less than _0.25Dp , and the amount of deformation of the deformed portion of the metal plug is _0.50Dp or more, and The distance between the tip of the deformed portion of the metal plug and the side surface of the laminate is _0.25Dp or more and less than _0.50Dp , and the deformation amount of the deformed portion of the metal plug is _0.75Dp or more. and the distance between the tip of the deformed portion of the metal plug and the side surface of the laminate is _0.50Dp or more and less than _0.75Dp , the degree of damage to the laminated rubber bearing is determined to be large. .

In a laminated rubber bearing in which a metal plug is provided in a laminate, as damage to the laminate progresses, the metal plug deforms laterally, and the deformation of the metal plug destroys the plate-like rubber of the laminate. do. As the damage to the laminate progresses further, the portion of the metal plug that breaks the plate-like rubber and is displaced laterally protrudes from the side surface of the laminate, thereby reducing the volume of the metal plug body and deteriorating the damping function. As a result, the performance of the laminate is greatly impaired. Therefore, according to the above embodiment, the relationship between the amount of deformation of the deformed portion of the metal plug and the distance between the tip of the deformed portion of the metal plug and the side surface of the laminate is defined by the initial diameter _Dp of the metal plug. and determining that the degree of damage to the laminated rubber bearing is large when these satisfy a predetermined relationship, the degree of damage to the laminated rubber bearing can be easily and appropriately evaluated.

In one embodiment of the method for inspecting a laminated rubber bearing, the deformed portion related to the metal plug includes a deformed portion of the metal plug and a deformed portion of the laminate connected to the deformed portion of the metal plug.

According to the above embodiment, as the damage to the laminate progresses, the metal plug is deformed, and the laminate connected to the deformed portion of the metal plug is also deformed. Therefore, by including the deformed portion of the metal plug and the deformed portion of the laminate connected to the deformed portion of the metal plug as the deformed portion related to the metal plug, it is possible to accurately evaluate the degree of damage to the laminated rubber bearing. .

An inspection method for a laminated rubber bearing according to one embodiment corrects the X-ray image according to the incident position and/or incident angle of X-rays on the laminated body.

According to the above embodiment, the X-ray image is corrected according to the incident position and/or the incident angle of the X-rays with respect to the laminate. Even if X-rays cannot be irradiated from the front of the laminate, the inside of the laminate can be accurately grasped and the laminate can be inspected accurately. Moreover, when the laminated rubber bearing has a metal plug in the laminate, the state of the metal plug in the laminate can be accurately grasped. Here, when a plurality of metal plugs are present in the laminate, by adjusting the incident position and/or the incident angle of the X-rays, the images of each metal plug can be photographed without overlapping. In this case, each metal plug can be accurately inspected by correcting the X-ray image according to the incident position and/or incident angle of the X-ray.

A method for inspecting a laminated rubber bearing according to one embodiment is to determine the position of a mark previously placed on the laminated body and the position of the image of the mark in the radiographic image. This is to specify the photographing position of the line photographed image.

According to the above embodiment, based on the actual position of the mark previously set on the laminate and the position of the image of the mark in the X-ray image, the photographing position of this X-ray image on the laminated rubber bearing is determined. can be specified. Therefore, the laminate can be inspected accurately. Here, the mark is preferably made of a material having a lower X-ray transmittance than the laminate. Further, when the same mark image is included in a plurality of radiographic images, the plurality of radiographic images are aligned based on the image of the mark, and the plurality of radiographic images are combined. It can be performed.

An inspection method for a laminated rubber bearing according to one embodiment is to create a plurality of X-ray images by setting different incident positions and/or incident angles of X-rays with respect to the laminated body, An X-ray photographed image for inspection is created by synthesizing the X-ray photographed images.

According to the above embodiment, a plurality of X-ray images are created by setting different incident positions and/or incident angles of X-rays with respect to the laminate. The incident position and incident angle of the X-ray are set to a position and angle that allow the inside of the laminate to be clearly photographed in each X-ray photographed image. By synthesizing these multiple X-ray images to create an X-ray image for inspection, the state inside the laminate can be accurately imaged, and the laminated rubber bearing can be accurately inspected. be able to.

An inspection method for a laminated rubber bearing according to one embodiment binarizes the X-ray image.

According to the above embodiment, the image of the laminate in the X-ray photographed image can be made clear by binarizing the X-ray photographed image. Therefore, it is possible to accurately grasp the state of the voids in the laminate and the metal plugs in the laminate. Here, regarding the amount of X-ray transmission through the members constituting the laminated rubber bearing, for example, the plate-like rubber of the laminate is relatively large, while the steel plate and metal plug are relatively small. Therefore, by binarizing the X-ray image, the shape of each component can be clearly defined so that, for example, a rubber plate, a steel plate, and a metal plug can be clearly distinguished by the difference in image color. can be expressed as

1 is a plan view showing a lead plug-containing laminated rubber bearing to which an inspection method according to an embodiment of the present invention is applied; FIG. 1 is a cross-sectional view of a laminated rubber bearing containing a lead plug; FIG. It is a figure which shows a mode that an X-ray is irradiated to the laminated rubber bearing containing a lead plug. FIG. 4 is a schematic diagram showing the relationship between an image of a lead plug in an X-ray image and the lead plug of the lead plug-containing laminated rubber bearing. It is a figure which shows the radiography image before correction|amendment. FIG. 10 is a diagram showing an X-ray image after correction; 1 is a radiographic image with the central axis of the X-ray positioned at the top of a laminated rubber bearing with lead plugs. FIG. 6B is an X-ray radiographic image with the central axis located below FIG. 6A. FIG. 6B is an X-ray radiographic image with the central axis located below FIG. 6B. FIG. 6C is an X-ray radiographic image with the central axis located below FIG. 6C. FIG. 6D is an X-ray radiographic image with the central axis located below FIG. 6D. FIG. 6E is a radiographic image obtained by combining portions of each of the radiographic images of FIGS. 6A-6E; FIG. FIG. 6E is a cross-sectional view of the lead-plugged laminated rubber bearing from which the radiographic images of FIGS. 6A-6E were obtained; 1 is an X-ray photographed image of a laminate of laminated rubber bearings. 7B is an image superimposing the contours of the components of the laminated rubber bearing included in the radiographic image of FIG. 7A. 1 is an X-ray photographed image of a laminate of laminated rubber bearings. 8B is an image superimposing the contours of the components of the laminated rubber bearing included in the radiographic image of FIG. 8A. It is an X-ray photography image which image|photographed the laminated body of another laminated rubber bearing. 9B is an image superimposing the contours of the components of the laminated rubber bearing included in the radiographic image of FIG. 9A. It is the figure which showed typically the cross section of the plane direction of a laminated rubber bearing. It is a graph used for determining the degree of damage of a laminated rubber bearing.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a plan view showing a laminated rubber bearing containing lead plugs as a laminated rubber bearing to which the inspection method of the embodiment is applied, and FIG. 2 is a sectional view of the laminated rubber bearing containing lead plugs. This lead plug-containing laminated rubber bearing 1 is installed in a road bridge as a structure.

This laminated rubber bearing 1 containing a lead plug includes a laminate 2 formed by alternately laminating a plurality of plate-like rubbers 7 and steel plates 8 . This laminate 2 has a rectangular parallelepiped shape with a square plane. The plate-like rubber 7 of the laminate 2 is made of natural rubber and adhered to the steel plate 8 by adhesive or vulcanization. The plate-shaped rubber 7 may be made of high damping rubber obtained by adding various resins and fillers to natural rubber and/or synthetic rubber.

One surface of the laminate 2, which is the upper surface in FIG. A body 3 is placed. On the other surface of the laminate 2, which is located on the lower side in FIG. 2, a lower connecting member 3 connected to the lower structure of the structure is arranged. A plurality of fixing holes 10 into which bolts, dowel pins, and the like for connection to the structure are screwed are provided at the edges of the upper and lower connecting bodies 3 .

The side surface of the laminate 2 and the side surfaces of the upper and lower connecting members 3 are covered with covering rubber 5 for preventing internal deterioration. The upper end of the covering rubber 5 is bent toward the plane side of the connector 3 so as to surround the edge of the upper connector 3 . The covering rubber 5 can be made of high damping rubber or natural rubber. High-damping rubbers include ethylene-propylene rubber, nitrile rubber, butyl rubber, halogenated butyl rubber, chloroprene rubber, isoprene rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene rubber, butadiene rubber, silicone rubber, mixtures thereof, and natural rubber. mixtures can be used.

The lead plug-containing laminated rubber bearing 1 is formed with four through holes penetrating through the upper and lower connecting bodies 3 and the laminated body 2 in the thickness direction. of lead plugs 4 are housed respectively. The lead plug 4 is made of lead with a purity of 99.9% or higher, and has a cylindrical shape with a central axis extending in the lamination direction of the plate-shaped rubber 7 and the steel plate 8 of the laminate 2 . The lead plugs 4 are arranged at positions forming vertices of a square on diagonal lines in a plan view of the lead plug-containing laminated rubber bearing 1 . After the upper and lower connectors 3 are fixed to the laminate 2, the lead plugs 4 are press-fitted into four through holes formed in the laminate direction of the laminate 2 and the connector 3. It is

This laminated rubber bearing 1 containing lead plugs is installed in a road bridge, and is arranged between a bridge pier, which is a lower structure, and a bridge girder, which is an upper structure. A connecting body 3 on the lower side of the lead plug-containing laminated rubber bearing 1 is connected to an anchor bolt installed on the upper end surface of a steel or concrete bridge pier. Also, the upper connecting body 3 is connected to a bolt screwed to the lower flange of the steel or concrete bridge girder.

Laminated rubber bearings 1 containing lead plugs that are installed on bridge piers and support bridge girders in this way are subjected to dead loads of superstructures, live loads that fluctuate due to the passing of vehicles, wind loads, seismic loads, and the like. do. In addition, vibrations caused by passing vehicles, wind, and earthquakes are transmitted to the laminated rubber bearing 1 with lead plugs. Furthermore, due to the expansion or contraction of the bridge member due to the temperature change, displacement occurs between the upper connecting body 3 and the lower connecting body 3 of the lead plug-containing laminated rubber bearing 1 . These loads, vibrations, and displacements may cause deformation of the lead plugs 4 in the laminated rubber bearing 1 containing lead plugs. Deformation of the lead plug 4 includes fracture where a cut surface is formed in the transverse direction at any position in the axial direction, and lead plug 4 between the plate rubber 7 and the steel plate 8 of the laminate 2 from the side surface of the lead plug 4. There is a flow that flows out. These deformations of the lead plugs 4 cannot be detected from the appearance of the laminate 2, but cause deterioration of the performance of the laminated rubber bearing 1 containing lead plugs. Therefore, according to the method for inspecting a laminated rubber bearing containing a metal plug according to the present embodiment, the laminated rubber bearing containing a lead plug 1 is inspected non-destructively without destruction, and deformation of the lead plug 4 is detected.

FIG. 3 is a schematic diagram showing how the laminated rubber bearing 1 containing a lead plug is inspected by the method for inspecting a laminated rubber bearing containing a metal plug according to the present embodiment. The inspection method of this embodiment includes an X-ray source 12 that generates and emits X-rays, and an imaging plate 13 as an X-ray detector that detects the X-rays emitted from the X-ray source 12 and transmitted through an object to be inspected. Use

The X-ray source 12 has an electron source, an X-ray target irradiated with an electron beam generated from the electron source, and an X-ray tube for generating X-rays. The imaging plate 13 utilizes the phenomenon of ^stimulable fluorescence, which is a phenomenon in which radiation energy is accumulated and then excited by heat, light, or the like to emit fluorescence. It has a film coated with microcrystals of A reader (not shown) reads the imaging plate 13 that has detected X-rays transmitted through the object to be inspected, thereby obtaining an X-ray image of the object to be inspected. The reader irradiates the surface of the film of the imaging plate 13 with laser light and reads the amount of light emitted from the film according to the amount of X-ray exposure with an optical scanner, thereby generating an X-ray image of the inspection object. . The X-ray source 12 and the imaging plate 13 operate in a stationary state with respect to the laminated rubber bearing 1 containing lead plugs. An X-ray image generated by the reader is input to a computer, and the function obtained by executing image processing software on this computer performs distortion correction processing and synthesis processing as follows. Note that the distortion corrected by the distortion correction processing refers to a shape that appears in the X-ray image so as to differ from the original shape of the member.

Conventionally, inspections using X-rays emitted from a stationary X-ray source on an object to be inspected have been targeted at objects with a small thickness, such as plate-shaped bodies and tubular bodies, such as laminated rubber bearings containing lead plugs. Conventionally, a large dimension in the transmission direction has not been targeted. The reason for this is that if the dimension in the transmission direction is large, the attenuation of X-rays is large, making it difficult to obtain a clear transmitted image. It's about to get bigger.

Moreover, in the laminated rubber bearing 1 containing lead plugs shown in FIG. Therefore, when X-rays are irradiated in a direction perpendicular to the side surface of the laminated rubber bearing 1 containing lead plugs, the X-rays that pass through the two lead plugs 4 are detected, so that one of the lead plugs 4 is damaged. There is a problem that it is not possible to identify In addition, since the laminated rubber bearing 1 with lead plugs is arranged between the upper end surface of the bridge pier and the lower flange of the bridge girder, the work area for inspection is narrow, and other structures are arranged close to each other. It is often done. Therefore, there is little space around the lead plug-containing laminated rubber bearing 1 for arranging the X-ray source 12 and the imaging plate 13, and the degree of freedom in the arrangement of the X-ray source 12 and the imaging plate 13 is low.

Therefore, in the method for inspecting a laminated rubber bearing containing a metal plug according to the present embodiment, as shown in FIG. X-rays are irradiated in an inclined direction with respect to the side surface of the X-ray, and are detected by an imaging plate 13 arranged on the side surface perpendicularly adjacent to the side surface on which the X-rays are incident. That is, the X-rays are detected by the imaging plate 13 arranged to be inclined with respect to the central axis Xa of the X-rays emitted from the X-ray source 12 . Since the X-ray image obtained in this manner contains distortion due to the characteristics of the X-ray, the distortion is corrected by image processing of a computer.

FIG. 4 is an X-ray image of the lead plug 4 detected by X-rays in which the central axis Xa is inclined by an angle (π/2-θ ₄ ) with respect to the normal to the side surface of the laminated rubber bearing 1 containing lead plugs. and damage occurring in the actual lead plug 4. FIG. In FIG. 4, reference numeral 18 denotes an X-ray image obtained by the imaging plate 13, aligned with the installation position of the imaging plate 13 in the width direction in the plan view of the laminated rubber bearing 1 containing lead plugs. The plan view of the lead plug-containing laminated rubber bearing 1 corresponds to the radiographic image 18 acquired by the imaging plate 13 and shows the damage caused to the lead plug 4 . In the radiographic image 18, 44 is the image of the lead plug 4, 45 is the image of the flow damage 15 on one side of the lead plug 4, and 46 is the flow damage on the other side of the lead plug 4. 16 is an image of lesion 16; The images 45 and 46 of the flow damage 15 and 16 of the lead plug 4 are hereinafter simply referred to as deformed portions. Although the flow damage 15 and 16 caused to the lead plug 4 does not reach the flow protrusion where the lead protrudes from the side surface of the laminate 2, the lead plug 4 is deformed, so the performance of the lead plug 4 is deteriorated. is doing. In order to accurately identify the deformed form of the lead plug 4, the distortion correction processing of the X-ray image 18 is performed as follows.

ここで、Ａは、Ｘ線源１２の焦点である。Ｂは、Ｘ線源１２の焦点から、鉛プラグ入り積層ゴム支承１のＸ線が入射する側面と平行に延ばした線と、検査対象の鉛プラグ４の中心Ｏから上記Ｘ線が入射する側面の法線方向に延ばした線との交点である。また、Ｃは、Ｘ線源１２の焦点から、鉛プラグ入り積層ゴム支承１のＸ線が入射する側面と平行に延ばした線と、イメージングプレート１３が設置された鉛プラグ入り積層ゴム支承１の側面であってＸ線が出射する側面を平行に延ばした線との交点である。また、Ｄは、Ｘ線源１２の焦点Ａから、鉛プラグ入り積層ゴム支承１のＸ線が入射する側面へ法線方向に延ばした線の交点である。また、Ｅは、鉛プラグ入り積層ゴム支承１のＸ線が入射する側面と、イメージングプレート１３が設置された鉛プラグ入り積層ゴム支承１の側面との交点である。また、Ｆは、イメージングプレート１３が設置された鉛プラグ入り積層ゴム支承１の側面において、イメージングプレート１３の一端に相当する点である。また、Ｇは、イメージングプレート１３の検出面の幅方向において、イメージングプレート１３に投射される鉛プラグ４の一方の流動損傷１５の端を示す点である。また、Ｈは、イメージングプレート１３の検出面の幅方向において、鉛プラグ４の一方の側の境界を示す点である。また、Ｉは、イメージングプレート１３の検出面の幅方向において、鉛プラグ４の他方の側の境界を示す点である。また、Ｊは、イメージングプレート１３の検出面の幅方向において、イメージングプレート１３に照射される鉛プラグ４の他方の流動損傷１６の端を示す点である。また、Ｋは、鉛プラグ入り積層ゴム支承１のＸ線が入射する側面が平面視において現れる線と、検査対象の鉛プラグ４の中心Ｏから上記Ｘ線が入射する側面の法線方向に延ばした線との交点である。また、Ｒは、イメージングプレート１３に投射される鉛プラグ４の一方の流動損傷１５の端を通るＸ線と、鉛プラグ４の中心Ｏを通ってイメージングプレート１３の検出面と平行な線との交点である。また、Ｓは、イメージングプレート１３に投射される鉛プラグ４の一方の側の境界を通るＸ線と、鉛プラグ４の中心Ｏを通ってイメージングプレート１３の検出面と平行な線との交点である。また、Ｔは、一方の流動損傷１５が生じた鉛プラグ４の側面と、鉛プラグ４の中心Ｏを通ってイメージングプレート１３の検出面と平行な線との交点である。また、Ｕは、他方の流動損傷１６が生じた鉛プラグ４の側面と、鉛プラグ４の中心Ｏを通ってイメージングプレート１３の検出面と平行な線との交点である。また、Ｖは、イメージングプレート１３に投射される鉛プラグ４の他方の側の境界を通るＸ線と、鉛プラグ４の中心Ｏを通ってイメージングプレート１３の検出面と平行な線との交点である。また、Ｗは、イメージングプレート１３に投射される鉛プラグ４の他方の流動損傷１６の端を通るＸ線と、鉛プラグ４の中心Ｏを通ってイメージングプレート１３の検出面と平行な線との交点である。また、Ｏは、鉛プラグ４の中心である。また、Ｐは、イメージングプレート１３に投射される鉛プラグ４の他方の側の境界を通るＸ線と、鉛プラグ４の側面との接点である。また、Ｑは、イメージングプレート１３に投射される鉛プラグ４の一方の側の境界を通るＸ線と、鉛プラグ４の側面との接点である。また、ｒは鉛プラグ４の半径である。 First, the distance between the symbols of each point shown in the plan view of FIG. 4 is set as follows.

where A is the focal point of the x-ray source 12 . B is a line extending from the focal point of the X-ray source 12 in parallel with the side surface of the lead plug-containing laminated rubber bearing 1 on which X-rays are incident, and a side surface of the lead plug 4 to be inspected from which the X-rays are incident from the center O. is the point of intersection with a line extending in the normal direction of . In addition, C is a line extending from the focal point of the X-ray source 12 in parallel with the side surface of the lead plug-containing laminated rubber bearing 1 on which X-rays are incident, and the lead plug-containing laminated rubber bearing 1 on which the imaging plate 13 is installed. It is the intersection with a line extending parallel to the side surface from which X-rays are emitted. D is the intersection of lines extending from the focal point A of the X-ray source 12 in the normal direction to the side surface of the lead plug-containing laminated rubber bearing 1 on which X-rays are incident. Further, E is an intersection point between the side surface of the laminated rubber bearing 1 containing lead plugs on which X-rays are incident and the side surface of the laminated rubber bearing 1 containing lead plugs on which the imaging plate 13 is installed. Further, F is a point corresponding to one end of the imaging plate 13 on the side surface of the lead plug-containing laminated rubber bearing 1 on which the imaging plate 13 is installed. G is a point indicating one end of the flow damage 15 of the lead plug 4 projected onto the imaging plate 13 in the width direction of the detection surface of the imaging plate 13 . H is a point indicating the boundary on one side of the lead plug 4 in the width direction of the detection surface of the imaging plate 13 . Also, I is a point indicating the boundary on the other side of the lead plug 4 in the width direction of the detection surface of the imaging plate 13 . J is a point indicating the other end of the flow damage 16 of the lead plug 4 irradiated to the imaging plate 13 in the width direction of the detection surface of the imaging plate 13 . In addition, K is a line in which the side surface of the lead plug containing laminated rubber bearing 1 on which the X-ray is incident appears in a plan view, and a line extending from the center O of the lead plug 4 to be inspected in the normal direction of the side surface on which the X-ray is incident. is the point of intersection with the line Also, R is the line between the X-ray passing through one end of the flow damage 15 of the lead plug 4 projected onto the imaging plate 13 and the line parallel to the detection surface of the imaging plate 13 passing through the center O of the lead plug 4. intersection. S is the intersection of the X-ray projected onto the imaging plate 13 and passing through one side boundary of the lead plug 4 and the line passing through the center O of the lead plug 4 and parallel to the detection surface of the imaging plate 13. be. T is the intersection of the side surface of the lead plug 4 where one of the flow damages 15 has occurred and a line passing through the center O of the lead plug 4 and parallel to the detection surface of the imaging plate 13 . U is the intersection of the side surface of the lead plug 4 where the other flow damage 16 has occurred and a line passing through the center O of the lead plug 4 and parallel to the detection surface of the imaging plate 13 . V is the intersection point of an X-ray projected onto the imaging plate 13 and passing through the boundary on the other side of the lead plug 4 and a line passing through the center O of the lead plug 4 and parallel to the detection surface of the imaging plate 13. be. Also, W is the line between the X-ray passing through the other end of the flow damage 16 of the lead plug 4 projected onto the imaging plate 13 and the line parallel to the detection surface of the imaging plate 13 passing through the center O of the lead plug 4. intersection. Also, O is the center of the lead plug 4 . P is the point of contact between the side surface of the lead plug 4 and the X-ray projected onto the imaging plate 13 and passing through the boundary on the other side of the lead plug 4 . Q is the point of contact between the X-ray passing through the boundary on one side of the lead plug 4 projected onto the imaging plate 13 and the side surface of the lead plug 4 . Also, r is the radius of the lead plug 4 .

ここで、

である。また、

である。また、

である。また、

である。 The length L11 of the deformed portion 45 corresponding to one flow damage ₁₅ and the length L12 of the deformed portion 46 corresponding to the other flow damage 16 in the radiographic image 18 detected by the imaging plate ₁₃ are Based on the geometric relationships shown in FIG. 4, it is expressed as follows.

here,

is. again,

is. again,

is. again,

is.

また、他方の流動損傷１６が鉛プラグ４の側面から流動した流動長について、Ｘ線撮影画像１８に投影された流動長から算出した第２流動長Ｌ_１４を、次の式により算出する。

さらに、これらの第１流動長Ｌ_１３及び第２流動長Ｌ_１４は、傾斜方向からの投影により、流動長が過少に評価される傾向にある。そこで、下記のように、流動損傷１５，１６を含めた全幅から鉛プラグ４の幅を差し引くことにより、上記第１及び第２流動長Ｌ_１３，Ｌ_１４よりも高い精度の合計流動長Ｌ_１５を求めることができる。

From these, the first flow length L ₁₃ calculated from the flow length projected on the X-ray image 18 is calculated by the following formula for the flow length of the one flow damage 15 flowing from the side surface of the lead plug 4 .

As for the flow length of the other flow damage 16 flowing from the side surface of the lead plug ₄ , the second flow length L14 calculated from the flow length projected on the radiographic image 18 is calculated by the following equation.

Furthermore, the first flow length _L13 and the second flow length _L14 tend to be underestimated due to projection from the oblique direction. Therefore, by subtracting the width of the lead plug 4 from the total width including the flow damages 15 and 16 as described below, the total flow length L ₁₅ with higher precision than the first and second flow lengths L ₁₃ and L ₁₄ is obtained. can be asked for.

By such strain correction processing, the inclination angle θ4 with respect to the lead plug-containing laminated rubber bearing ₁ , the distance between the X-ray source 12 and the imaging plate 13, the lead plug-containing laminated rubber bearing 1 and the X-ray source 12 Based on the distance between and the like, it is possible to correct the dimensional distortion of the lead plug 4 in the radiographic image and obtain the total flow length _L15 , which is substantially the actual size flow length of the lead plug 4 . Note that the first and second flow lengths L ₁₃ and L ₁₄ may be employed as flow lengths.

By performing the above-described distortion correction processing on a plurality of cross sections in the height direction of the laminated rubber bearing 1 containing lead plugs, the X-ray radiographic image 18 acquired by the imaging plate 13 can be corrected.

Further, in the distortion correction process, as described above, correction is performed based on the X-ray irradiation angle of the X-ray source 12, the geometric relationship between the irradiation path of the X-rays and the constituent parts of the laminated rubber bearing 1 containing lead plugs. In addition, based on the original shape of the constituent parts of the lead plug-containing laminated rubber bearing 1, the radiographic image is corrected. FIG. 5A is a radiographic image showing the side of the lead plug 4 before distortion correction processing as correction is performed, and FIG. 5B is the side of the lead plug 4 after distortion correction processing as correction is performed. 1 is an X-ray image showing . As shown in FIG. 5A , in the X-ray image before correction, the edges of the image of the steel plate 41 of the laminate 2 appear tapered toward the tip due to diffusion with increasing distance from the X-ray source. . Since the steel plate 41 of the laminate 2 is originally formed to have a uniform thickness, the distortion of the X-ray image is corrected so that the steel plate 41 has the original shape. Specifically, a predetermined region including the tapered portion of the image of the steel plate 41 in FIG. 5A is deformed so that the tapered portion becomes parallel. Thus, by correcting the X-ray image so that the shape of the image of the member in the X-ray image becomes the original shape, the distortion of the X-ray image can be effectively corrected. . The lead plug 4 can be inspected using the X-ray image corrected by the distortion correction. For example, according to FIG. 5B, it can be seen that the uneven portion 19 is formed on the side surface of the lead plug 44 and the lead flow causes damage.

It is preferable that the X-ray image is subjected to distortion correction processing and then synthesis processing. In the lead plug-containing laminated rubber bearing 1, a plurality of steel plates 8 extend parallel to each other in the plane direction within the laminated body 2. Therefore, when an X-ray is incident on the side surface of the laminated body 2, the central axis Xa of the X-ray In the X-ray image acquired by the imaging plate 13, the steel plate 8 positioned away from the laminate 2 in the height direction appears as an image projected obliquely in the height direction. Therefore, in the method for inspecting a laminated rubber bearing with a metal plug according to the present embodiment, the X-ray irradiation positions of the X-ray source 12 are set at five different positions in the height direction to obtain X-ray images. From each of the five acquired X-ray radiographed images, portions near the height corresponding to the central axis Xa of X-rays are taken out, and the taken out portions are combined to create one X-ray radiographed image.

6A-6E are radiographic images used to perform the compositing process. 6A is an X-ray radiographic image in which the X-ray central axis Xa is located above the laminate 2, and FIG. 6B is an X-ray image in which the X-ray central axis Xa is located below the laminate 2 in FIG. FIG. 6C is a radiographic image in which the central axis Xa of the X-ray is positioned lower than the laminated body 2 in FIG. 6B, and FIG. 6C, and FIG. 6E is an X-ray radiographic image in which the central axis Xa of the X-ray is located below the laminate 2 in FIG. 6D. From each of these X-ray imaging images, a height portion corresponding to the central axis Xa of X-rays is extracted over a predetermined height, and the extracted portions are arranged sequentially in the height direction, resulting in FIG. 6F. Such radiographic images are obtained. 6A to 6E, portions with little distortion in the height direction are extracted and combined in the height direction to create the X-ray image of FIG. 6F. FIG. 6G is a cross-sectional view showing a state in which the laminated rubber bearing 1 containing a lead plug, which has been irradiated with X-rays and acquired an X-ray image, is cut. As is clear from a comparison of FIGS. 6F and 6G, an accurate radiographic image showing the inside of the laminate 2 of the lead plug-containing laminated rubber bearing 1 can be obtained by performing the synthesizing process. For example, flow portion 20 of lead plug 4 in FIG. 6G clearly appears as flow portion 46 of lead plug 44 in FIG. 6F. In this way, the synthesizing process synthesizes X-ray images acquired by irradiating X-rays from different heights, thereby obtaining a clear X-ray image of the laminate 2 with little distortion. Therefore, it is possible to accurately grasp the shape of the lead plug 4 and perform an accurate inspection. The radiographic images to be synthesized may be obtained by irradiating the laminated body 2 with X-rays from different positions in the height direction, or may be obtained by irradiating X-rays with different incident angles.

Next, the degree of damage to the laminated rubber bearing is determined based on the X-ray image obtained by performing the distortion correction processing and synthesis processing as described above. FIG. 7A is a part of an X-ray image obtained by photographing the laminated body of the laminated rubber bearing to be judged, and FIG. 7B is a configuration of the laminated rubber bearing included in the X-ray image of FIG. 7A. It is the image which showed the outline of a part superimposed.

The laminate of the radiographic image in FIG. 7A is formed by alternately laminating plate-like rubber 57 and steel plate 58 between one connector 53 and the other connector (not shown). Used in laminated rubber bearings without metal plugs. As shown in FIG. 7B, an X-ray image of this laminate shows a gap 60 between the rubber plate 57 and the steel plate 58 and a gap 61 in the rubber plate 57 . It is assumed that the gap 60 between the plate-like rubber 57 and the steel plate 58 is caused by the shearing force applied to the laminate, which destroys the adhesion between the plate-like rubber 57 and the steel plate 58 and separates them. In addition, the gap 61 in the plate-like rubber 57 is such that the shearing force received by the laminated body is applied to the plate-like rubber 57 , the steel plate 58 adhered to one surface of the plate-like rubber 57 and the other side of the plate-like rubber 57 . It is presumed that this plate-like rubber 57 was destroyed by the action of the connection body 53 adhered to the surface of , and a gap was formed. When the adhesion between the plate-shaped rubber 57 and the steel plate 58 or the connection body 53 is broken in this way, and when the plate-shaped rubber 57 is broken, the easiness of deformation of the laminate in the shear direction increases. , the shear deformation performance of the laminated rubber bearing deteriorates. Therefore, when gaps 60 and 61 exist in the laminated body of the radiographic image as shown in FIG. 7A, the degree of damage to the laminated rubber bearing is determined to be large. For laminated rubber bearings judged to have a large degree of damage, take mechanical countermeasures, such as adding a member that shares the horizontal force acting on the laminated rubber bearing, or replace the laminated rubber bearing. On the other hand, if there is no gap in the laminate in the radiographic image, it is determined that there is no change in the easiness of deformation of the laminate in the shear direction, and the degree of damage is zero.

Thus, by using an X-ray photographed image of the laminated rubber bearing, it is determined that the degree of damage to the laminated rubber bearing is large when the gaps 60 and 61 appear in the laminate of the laminated rubber bearing. , the degree of damage can be appropriately determined even for laminated rubber bearings whose soundness is unknown from the outside. Therefore, it is possible to prevent problems such as the laminated rubber bearing not exerting its damping function during an earthquake.

In the above embodiment, when the gaps 60 and 61 appear in the laminate in the X-ray image of the laminated rubber bearing, it is determined that the damage to the laminated rubber bearing is large. The degree of damage may be determined based on the position and size.

In the above-described embodiment, the degree of damage was determined for the laminated body of the laminated rubber bearing having no metal plug in the laminated body formed by alternately laminating the plate-shaped rubber 57 and the steel plate 58. Laminates of bearings can also be assessed for damage based on voids.

Next, a case of determining the degree of damage of a laminated rubber bearing having a metal plug in the laminated body based on an X-ray image will be described. FIG. 8A is a part of an X-ray image obtained by photographing the laminated body of the laminated rubber bearing to be judged, and FIG. 8B is a configuration of the laminated rubber bearing included in the X-ray photographed image of FIG. 8A. It is the image which showed the outline of a part superimposed.

In the laminated rubber bearing to be judged, a lead plug as a metal plug is arranged in the laminated body. FIG. 8A is an X-ray image of the laminated rubber bearing, showing the damaged portion of the lead plug and its surroundings. As shown in FIG. 8B, the main steel plates 78 of the laminate, the sub-steel plates 79 arranged between the main steel plates 78, the lead plugs 74, and the plate-like rubber 77 appear in the radiographic image. The main steel plate 78 is arranged so as to occupy substantially the entire cross section of the laminate, while the sub steel plate 79 is arranged in a part of the cross section of the laminate and surrounding the lead plug 74 . . The lead plug 74 had a columnar shape inserted into a through hole penetrating the main steel plate 78 , the sub steel plate 79 and the plate-shaped rubber 77 at the time of manufacture. In this laminate, as shown in FIG. 8A, the lead plug 74 is laterally deformed along the lower surface of the sub-steel plate 79, and in the plate-like rubber 77 at the tip of the deformed portion 80 of the lead plug 74, A void 81 appears. It is assumed that the laminate of this laminated rubber bearing was damaged through the following process. That is, the laminated body of the laminated rubber bearing undergoes shear deformation due to an earthquake or temperature, and as a result, a gap is generated between the lead plug 74 and the plate-like rubber 77 . The lead of the lead plug 74 flows into the gap between the lead plug 74 and the plate-shaped rubber 77 to form a deformed portion 80 projecting from the original columnar shape.

FIG. 9A is a part of an X-ray image obtained by photographing another laminate of laminated rubber bearings as a determination target, and FIG. Figure 2 is an image showing superimposed outlines of the components of the bearing;

In this laminated rubber bearing, lead plugs are arranged as metal plugs in the laminated body, and FIG. 9A is an X-ray image obtained by photographing this laminated rubber bearing, showing a damaged portion of the lead plug and its peripheral portion. It is a thing. As shown in FIG. 9B, the main steel plates 88 of the laminate, the sub steel plates 89 arranged between the main steel plates 88, the lead plugs 84, and the plate-like rubber 87 appear in the radiographic image. The lead plug 84 had a columnar shape inserted into a through hole penetrating the main steel plate 88 , the sub steel plate 89 , and the plate-shaped rubber 87 at the time of manufacture. In this laminate, as shown in FIG. 9A, the sub-steel plate 89 that was parallel to the main steel plate 88 at the time of manufacture is inclined, and the lead plug 84 is laterally deformed along the lower surface of this sub-steel plate 89. . A gap 91 appears in the plate-like rubber 87 from the bottom to the tip of the deformed portion 90 of the lead plug 84 . It is assumed that the laminate of this laminated rubber bearing was damaged through the following process. That is, the laminated body of the laminated rubber bearing undergoes shear deformation due to an earthquake or temperature, thereby forming gaps between the lead plug 84 and the plate-like rubber 87 and between the sub-steel plate 89 and the plate-like rubber 87 . The lead of the lead plug 84 flows into these gaps to form a deformed portion 90 projecting from the original columnar shape.

Based on the X-ray image showing the deformation of the lead plugs 74, 84 and the gaps 81, 91 of the plate-like rubbers 77, 87, the degree of damage to the laminated rubber bearing is determined as follows.

FIG. 10 is a diagram schematically showing a cross-section in the plane direction of the laminated rubber bearing, and schematically showing locations corresponding to parameters used for determining the degree of damage of the laminated rubber bearing. As shown in FIG. 10, to determine the degree of damage to the laminated rubber bearing, the manufacturing diameter _Dp of the lead plug 102 and the length _Bp of the deformed portion 103 with respect to the lead plug 102 are specified. Also, the distance _Cr between the tip of the deformed portion 103 related to the lead plug 102 and the side surface of the laminate 100 on the tip side of the deformed portion 103 is specified. The deformed portion 103 of the lead plug 102 is a combined portion of the deformed portion of the lead plug 102 and the deformed portion of the rubber 101 . Further, the tip of the deformed portion 103 with respect to the lead plug 102 refers to the portion of the deformed portion 103 closest to the side surface of the laminate 100 . Further, the rubber 101 includes plate-like rubber laminated in the thickness direction of the laminate and covering rubbers provided on the side surfaces of the laminate.

The parameter values specified as shown in FIG. 10 are compared with the damage degree determination table shown in Table 1 below to determine the degree of damage to the laminated rubber bearing. In Table 1, the lead plug damage dimension _Bp is the length _Bp of the deformed portion of the lead plug 102 . The cover _Cr of the lead plug is the distance _Cr between the tip of the deformed portion of the lead plug 102 and the side surface of the laminate 100 on the tip side of the deformed portion. For the lead plug damage dimension _Bp and the lead plug cover _Cr , values defined by the diameter _Dp of the lead plug 102 at the time of manufacture are used.

FIG. 11 is a graph showing the damage degree determination table of Table 1 with the damage dimension _Bp of the lead plug on the horizontal axis and the cover _Cr of the lead plug on the vertical axis. As shown in the damage degree determination table of Table 1 and the damage _{degree determination graph} of FIG. If it is _p or more, it is determined that there is no damage to the laminated rubber bearing. On the other hand, the damage dimension _Bp of the lead plug 102 is less than _0.25Dp and the cover _Cr of the lead plug 102 is _0.25Dp or more and less than _0.75Dp , and the damage dimension of the lead plug 102 is When Bp is _0.25Dp or more and less than _0.50Dp , and the cover _Cr of the lead plug 102 is _{0.75Dp or} more, it is determined that the damage to the laminated rubber bearing is small. On the other hand, when the damage dimension _Bp of the lead plug 102 is _0.25Dp or more and less than _0.50Dp and the cover _Cr of the lead plug 102 is _0.25Dp or more and less than _0.75Dp ; When the damage dimension Bp of the plug 102 is 0.50 _Dp or more and less than _0.75Dp and the cover _Cr of the lead plug 102 is _0.50Dp or more, and when the damage dimension _Bp of the lead plug ₁₀₂ is _0.75Dp or more and less than _1.00Dp , and the cover _Cr of the lead plug 102 is _0.75Dp or more, and the damage dimension _Bp of the lead plug 102 is _1.00Dp or more, In addition, when the cover _Cr of the lead plug 102 is _0.75Dp or more, it is determined that the laminated rubber bearing is moderately damaged. On the other hand, the damage dimension _Bp of the lead plug 102 is _0.25Dp or more and less than _0.50Dp and the cover _Cr of the lead plug 102 is less than _0.25Dp , and the damage dimension of the lead plug 102 When _Bp is _0.50Dp or more and less than _0.75Dp and the cover Cr of the lead plug 102 is less than _0.50Dp , and when the damage dimension _Bp of the lead plug 102 is _{0.75Dp or} more _{1.00 Dp} or less and the cover _Cr of the lead plug 102 is less than _{0.75 Dp} ; If the fogging _Cr is less than _0.75Dp , the damage to the laminated rubber bearing is determined to be large.

The lead plug damage determination table and damage determination graph are based on the fact that the lead plug-containing laminated rubber bearing is damaged through the following process. That is, when the laminate 100 of the laminated rubber bearing is deformed due to an earthquake or temperature, the adhesion between the rubber plate and the lead plug 102 and the adhesion between the rubber plate and the steel plate are destroyed. As a result, gaps are formed between the plate-like rubber and the lead plug 102, between the plate-like rubber and the steel plate, and inside the plate-like rubber. As the deformation of the laminate 100 progresses, the lead of the lead plug 102 flows into the gap and forms a deformed portion protruding from the original columnar surface of the lead plug 102 . If the deformation of the laminate 100 progresses further, the damage to the plate-shaped rubber progresses further, thereby further increasing the flow of lead in the lead plug 102 . When the flow of lead increases, the coating rubber on the side surface of the laminate 100 is destroyed, and lead flows out from the side surface of the laminate 100 to the outside. This reduces the amount of lead in the main body of the lead plug 102 and significantly reduces the damping performance of the laminated rubber bearing. When lead flows out from the laminated body 100, the laminated rubber bearing reaches a state of destruction. In the course of such destruction of the laminated rubber bearing, if the protrusion of the lead plug 102 is less than 0.25 _Dp , the damping function of the laminated rubber bearing containing the lead plug does not deteriorate significantly. On the other hand, if the cover Cr of the lead plug 102 is less than _{0.50 Dp} , the possibility of lead flowing out due to the deformation of the lead plug 102 increases, increasing the risk of reducing the damping function of the lead plug-containing laminated rubber bearing. . With regard to the damage dimension _Bp of the lead plug 102 and the cover _Cr of the lead plug 102, the damage degree determination table of Table 1 can be created.

Based on the radiographic images of FIGS. 8B and 9B, the damage dimensions of the lead plugs 74 and 84 and the covering of the lead plugs 74 and 84 are specified, and by referring to the damage degree determination table of Table 1, the lead plugs Determine the degree of damage to the laminated rubber bearing. The damage dimensions and fogging of the lead plugs 74 and 84 are determined by the drawings at the time of manufacturing the laminated rubber bearing with lead plugs, the position of the light source when the X-ray image was taken, the position of the imaging plate 13, and the incidence of X-rays. Identify based on angle. In addition, as shown in FIG. 9B, based on the position in the image of the marker image 93 appearing in the X-ray image and the arrangement position of the marker in the lead plug-containing laminated rubber bearing, The dimensions of each part are calculated, and the damage dimensions and fogging of the lead plugs 74 and 84 are specified. Here, in the image of FIG. 8B, the damage dimension of the lead plug 74 is the distance between the surface of the lead plug 74 before deformation and the most tip position of the deformed portion 80 and the gap 81 . Also, in the image of FIG. 9B, the damage dimension of the lead plug 84 is the distance between the surface of the lead plug 84 before deformation and the most tip position of the deformed portion 90 and the gap 91 . By comparing the damage dimensions of the lead plugs 74 and 84 identified in this manner and the cover of the lead plugs 74 and 84 with the damage degree determination table of Table 1, the degree of damage of the laminated rubber bearing containing lead plugs is determined. can be done.

If it is determined that there is no damage to the laminated rubber bearing with lead plugs, no action is required. On the other hand, when the degree of damage is determined to be small, there is concern that the lead in the lead plug 102 may flow out of the laminate 100, so follow-up is performed. On the other hand, if the degree of damage is determined to be medium, there is a strong concern that the lead in the lead plug 102 will flow out of the laminate 100, so countermeasures will be considered. On the other hand, if the degree of damage is determined to be large, the lead in the lead plug 102 may flow out of the laminate 100, so mechanical countermeasures should be taken to reduce the shear force acting on the lead plug-containing laminated rubber bearing. and replace laminated rubber bearings with lead plugs.

As described above, according to the laminated rubber bearing inspection method of the present embodiment, the damage dimensions and fogging of the lead plugs 74 and 84 are specified based on the X-ray image of the laminated rubber bearing containing lead plugs, and the degree of damage is determined. By referring to the table, it is possible to appropriately determine the degree of damage even for a laminated rubber bearing containing a lead plug, which is unknown from the outside. Therefore, it is possible to prevent problems such as the laminated rubber bearing containing lead plugs failing to exhibit a damping function during an earthquake.

As described above, according to the method for inspecting the laminated rubber bearing of each of the above embodiments, the laminated rubber bearing 1 is inspected in a non-destructive manner without destroying it at the original position where the laminated rubber bearing 1 is installed. , 100 and lead plugs 4, 44, 74, 84, 102 can be detected. In addition, the laminated rubber bearing 1 installed between the bridge pier and the bridge girder has a small space for inspection, and the X-ray irradiation direction of the X-ray source 12 is inclined with respect to the imaging plate 13. However, by performing distortion correction processing and synthesis processing on the X-ray photographed images, the laminates 2 and 100 and the lead plugs 4, 44, 74, 84 and 102 can be accurately inspected. Moreover, based on the voids 60 and 61 in the laminates 2 and 100 appearing in the X-ray radiographic images, the degree of damage that is unknown from the appearance of the laminates 2 and 100 can be determined non-destructively. Also, based on the damage size _Bp of the lead plugs 74, 84 in the laminate 2, 100 and the cover _Cr of the lead plugs 74, 84 appearing in the radiographic image, the appearance of the laminate 2, 100 can determine the unknown degree of damage non-destructively. As a result, appropriate measures can be taken for the laminated rubber bearing 1 .

In the above embodiment, an X-ray image with less distortion is formed by synthesizing a plurality of X-ray images. It is preferable to attach a mark that appears in the radiographic image. A plurality of X-ray images captured in this manner can be easily combined by using the image of the mark in the X-ray image as a reference.

Further, in the above-described embodiment, binarization of an X-ray image may be performed prior to distortion correction processing and synthesis processing. Since the laminated rubber bearing has a long distance through which X-rays pass, attenuation is likely to occur. In particular, in the lead plug-containing laminated rubber bearing 1, the distance through which the plate-shaped rubbers 7, 57, 77, 87 and the steel plates 8, 41, 58, 78, 79, 88, 89 constituting the laminated bodies 2, 100 are transmitted is Since it is longer than the distance that passes through the lead plugs 4, 44, 74, 84, 102, the lead plugs adjacent to the plate-like rubbers 7, 57, 77, 87 or the steel plates 8, 41, 58, 78, 79, 88, 89 4, 44, 74, 84, and 102 tend to be blurred. Here, by binarizing the X-ray image, the images of the lead plugs 4, 44, 74, 84, 102 can be made clearer. 102 accurate tests can be performed. In addition, while the plate-like rubbers 7, 57, 77, 87 of the laminates 2, 100 have relatively large amounts of X-ray transmission through the members constituting the laminated rubber bearing 1 with metal plugs, the steel plates 8, 41, 58, 78 , 79, 88, 89 and lead plugs 4, 44, 74, 84, 102 are relatively few. Therefore, by binarizing the X-ray image, the plate-like rubbers 7, 57, 77, 87 of the laminate 2, 100, the steel plates 8, 41, 58, 78, 79, 88, 89 and the lead The plugs 4, 44, 74, 84, 102 can be clearly distinguished. In this way, in order to clarify the X-ray photographed image of the laminated rubber bearing 1 with a metal plug, the binarization process is effective due to the difference in the X-ray transparency of the constituent members.

In the above embodiment, an example of inspecting the laminated rubber bearing 1 with lead plugs 4, 44, 74, 84, 102 as the laminated rubber bearing with metal plugs was described. It may be a laminated rubber bearing with a metal plug having a metal plug formed of the material. The inspection method of the present invention is applicable to laminated rubber bearings containing metal plugs having various metal plugs having a damper function.

In the above embodiment, the case where the present invention is applied to the lead plug-containing laminated rubber bearing 1 installed on a road bridge has been described, but it is not limited to road bridges, and can be applied to various types of bridges such as railway bridges, pedestrian bridges, pipeline bridges, and the like. The present invention can be applied to bridge bearings. Moreover, the present invention can be applied not only to bearings for bridges but also to bearings as vibration isolation devices installed on the foundations of buildings such as buildings. It can also be applied to a bearing as a vibration isolator installed in a plant structure.

Although the present invention has been described through the embodiments, various modifications are possible without departing from the gist of the present invention, and the technical scope of the present invention is not limited to the above embodiments.

1 Laminated rubber bearing with lead plug 2,100 Laminate 3 Connector 4,44,74,84,102 Lead plug 5 Covered rubber 7,57,77,87 Plate-shaped rubber 8,41,58,78,79,88 , 89 Steel plate 12 X-ray source 13 Imaging plate 15, 16 Flow damage 18 Radiographic image 19, 45, 46, 80, 90 Deformed part of lead plug 60, 61, 81, 91 Void

Claims (7)

A laminate obtained by alternately laminating a plurality of plate-like rubbers and steel plates, a connection body disposed on one side and the other side of the laminate and connected to a structure, and the laminate and the connection body A method for inspecting a laminated rubber bearing including a metal plug having a damper function and extending in the lamination direction of the plate-shaped rubber and steel plates penetrating therethrough, the method comprising:
At the original position where the laminated rubber bearing is installed, the laminate is irradiated with X-rays to obtain an X-ray image, and the amount of deformation of the deformed portion of the metal plug in the X-ray image and the amount of deformation of the metal plug in the X-ray image. A method for inspecting a laminated rubber bearing, characterized in that the degree of damage to the bearing is determined based on the distance between the tip of the deformed portion relating to the plug and the side surface of the laminated body. In the method for inspecting a laminated rubber bearing according to claim 1 ,
Assuming that the initial diameter of the metal plug in the radiographic image is _Dp , the amount of deformation of the deformed portion of the metal plug is 0.25 _Dp or more, and the tip of the deformed portion of the metal plug and the laminate is less than _0.25Dp , the amount of deformation of the deformed portion related to the metal plug is _0.50Dp or more, and the tip of the deformed portion related to the metal plug and the laminate The distance from the side surface is _0.25Dp or more and less than _0.50Dp , the amount of deformation of the deformed portion related to the metal plug is _0.75Dp or more, and the tip of the deformed portion related to the metal plug and the side surface of the laminate is _0.50Dp or more and less than _0.75Dp , the laminated rubber bearing is judged to have a large degree of damage. In the method for inspecting a laminated rubber bearing according to claim 1 ,
A method of inspecting a laminated rubber bearing, wherein the deformed portion of the metal plug includes a deformed portion of the metal plug and a deformed portion of the laminate connected to the deformed portion of the metal plug. In the method for inspecting a laminated rubber bearing according to claim 1 ,
A method for inspecting a laminated rubber bearing, wherein the X-ray photographed image is corrected according to the incident position and/or incident angle of X-rays with respect to the laminated body. In the method for inspecting a laminated rubber bearing according to claim 1 ,
The radiographic image capturing position of the laminated rubber bearing is specified based on the position of a mark pre-installed on the laminate and the position of the image of the mark in the radiographic image. A method for inspecting laminated rubber bearings. In the method for inspecting a laminated rubber bearing according to claim 1 ,
A plurality of the radiographic images are created by setting different incident positions and/or incident angles of X-rays with respect to the laminate, and these plurality of radiographic images are synthesized to obtain an X-ray for inspection. A method for inspecting a laminated rubber bearing, characterized by creating a radiographic image. In the method for inspecting a laminated rubber bearing according to claim 1 ,
A method for inspecting a laminated rubber bearing, characterized in that the X-ray photographed image is binarized.

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