JP5385250B2 - Seismic improvement method for existing pin bearings - Google Patents

Description

  The present invention relates to a method for making an existing pin bearing earthquake resistant, and more particularly to a technique for improving the earthquake resistance of an existing pin bearing installed between upper and lower structures in a bridge.

  A pin bearing is known as a bearing that is installed between the upper and lower structures of a bridge and vertically supports the upper structure in a rotatable manner. As a form of this pin support, there is one in which a pin is fitted to a semi-cylindrical boss portion provided on each of the upper and lower ridges (for example, see Non-Patent Document 1).

  This type of pin bearing is referred to as a bearing type, and the horizontal force in the direction perpendicular to the bridge axis is transmitted between the upper and lower structures via the pins. Specifically, a semi-annular convex portion is provided on the inner periphery of the axially intermediate portion of each semicylindrical boss portion of the upper collar and the lower collar, and by forming a reduced diameter portion in the axially intermediate portion of the other pin, An annular groove into which these semi-annular protrusions fit is provided. Further, an axial gap is formed between the end surface of the semi-annular convex portion and the wall surface of the annular groove so as not to inhibit the rotation of the upper structure. With such a structure, when a horizontal force in a direction perpendicular to the bridge axis acts on the upper structure, the load is transmitted to the pin while the semi-annular convex portion comes into contact with the wall surface of the annular groove and further transmitted to the lower structure.

  However, the horizontal force in the direction perpendicular to the bridge axis in the pin bearing is transmitted only by contact between the semi-annular convex portion and the wall surface of the annular groove. For this reason, for example, if a large level of ground motion such as Level 2 ground motion (the ground motion shown in the “Road Bridge Specification (V Seismic Design) / Description” (Japan Road Association)) occurs, There is a concern that an excessive stress is applied to the reduced diameter portion of the pin to be formed and the pin structure is damaged, leading to the fall of the superstructure.

  Replacing the existing pin bearing with a new one that takes earthquake resistance into account can solve the above problems, but replacing the entire bearing not only incurs significant construction costs but also gives it to vehicle traffic The impact is also great. For this reason, there is a demand for a measure for improving the earthquake resistance while using the existing pin support as it is.

“A Illustrated Bridge Terminology” by Shoichi Saeki, Sankai-do Co., Ltd., May 20, 1993 (6th edition), p. 256-257

The present invention has been made based on the technical background as described above, and achieves the following object.
An object of the present invention is to provide a method capable of improving the seismic resistance in a state where it is used without exchanging the entire existing pin support and suppressing the construction cost extremely low.

  As a result of intensive studies in order to solve the above-mentioned problems, the present inventors have focused on caps that are screwed to both end shaft portions of the pins so as to cover the semicylindrical boss portions of the upper and lower collars. did. When the horizontal force acts on the superstructure, not only the semi-annular protrusion and the wall surface of the annular groove abut, but at the same time, if the end surface of the semi-cylindrical boss part also abuts on the cap, The force is transmitted to both end shaft portions of the pin through the screwed portion between the cap and the pin, and the horizontal force is shared by three portions of the both end shaft portions in addition to the reduced diameter portion of the pin axially intermediate portion. So it was found that pin damage is prevented.

The present invention is based on the above knowledge and employs the following means.
That is, the first of the present invention is an upper collar fixed to the upper structure, having a semi-cylindrical boss portion at the lower portion, and forming a semi-annular convex portion along the circumferential direction on the inner periphery of the axial intermediate portion. With the upper arm
A lower arm fixed to the lower structure, having a semi-cylindrical boss portion on the upper portion, and a semi-annular convex portion formed on an inner periphery in the axial direction thereof;
A pin in which the semicylindrical bosses of the upper and lower collars are respectively fitted, and an annular groove in which the semicircular projections of the upper and lower collars are fitted in the axial intermediate portion thereof is defined. A pin having a reduced diameter portion and having an axial gap formed between the axial end surface of each semi-annular convex portion and the wall surface of the annular groove;
A cap screwed to shaft portions formed at both ends of the pin, the cap portion having a mounting hole into which the shaft portion is inserted at the center, and an outer periphery of the lid portion, the cap And an existing pin support comprising a cap having a cylindrical portion covering the end of each semi-cylindrical boss portion of the lower arm,
The cap includes a dimension of an axial gap (a) between an axial end surface of the semi-annular convex portion and a wall surface of the annular groove, an axial end surface of the semi-cylindrical boss portion, and a lid portion of the cap. The present invention is an earthquake resistance improvement method for an existing pin support, characterized in that the cap is replaced with a replacement cap formed so that the dimension of the axial gap (b) between the inner surface and the inner surface becomes equal.

A second aspect of the present invention is an upper collar fixed to the upper structure, having a semi-cylindrical boss portion supported by a plurality of ribs at the lower portion, and along the inner periphery of the axial direction along the circumferential direction. An upper collar formed with a semi-annular convex part,
A lower arm fixed to the lower structure, having a semi-cylindrical boss portion supported by a plurality of ribs on the upper portion, and a semi-annular convex portion formed on the inner periphery in the axial direction,
A pin in which the semicylindrical bosses of the upper and lower collars are respectively fitted, and an annular groove in which the semicircular projections of the upper and lower collars are fitted in the axial intermediate portion thereof is defined. A pin having a reduced diameter portion and having an axial gap formed between the axial end surface of each semi-annular convex portion and the wall surface of the annular groove;
A cap screwed into shaft portions formed at both ends of the pin, the lid portion having a mounting hole into which the shaft portion is inserted in the center, and an outer periphery of the lid portion. And a cap having a cylindrical portion covering the end of each semi-cylindrical boss portion of the lower arm, and a replacement cap for an existing pin bearing,
The cap has a dimension of an axial gap (a) between the axial end surface of the semi-annular protrusion and the wall surface of the annular groove, and an axial direction between the rib and the end surface of the cylindrical portion of the cap. In the method of making an existing pin bearing earthquake resistant, the replacement cap is formed with a cylindrical portion so that the dimension of the gap (c) becomes equal.

Further, the third aspect of the present invention is an upper collar fixed to the upper structure, having a semi-cylindrical boss portion supported by a plurality of ribs at the lower portion, and extending along the circumferential direction on the inner periphery of the axial intermediate portion thereof An upper collar formed with a semi-annular protrusion,
A lower arm fixed to the lower structure, having a semi-cylindrical boss portion supported by a plurality of ribs on the upper portion, and a semi-annular convex portion formed on the inner periphery in the axial direction,
A pin in which the semicylindrical bosses of the upper and lower collars are respectively fitted, and an annular groove in which the semicircular projections of the upper and lower collars are fitted in the axial intermediate portion thereof is defined. A pin having a reduced diameter portion and having an axial gap formed between the axial end surface of each semi-annular convex portion and the wall surface of the annular groove;
A cap screwed into shaft portions formed at both ends of the pin, the lid portion having a mounting hole into which the shaft portion is inserted in the center, and an outer periphery of the lid portion. And an existing pin support comprising a cap having a cylindrical portion covering the end of each semi-cylindrical boss portion of the lower arm,
The cap includes a dimension of an axial gap (a) between an axial end surface of the semi-annular convex portion and a wall surface of the annular groove, an axial end surface of the semi-cylindrical boss portion, and a lid portion of the cap. The lid portion is formed so that the dimension of the axial clearance (b) between the inner surface and the inner surface is equal, and the axial clearance (a ) And an exchange cap formed with a cylindrical part so that the dimension of the axial gap (c) between the rib and the end face of the cylindrical part of the cap becomes equal. It is in the method of earthquake resistance of pin bearings.

  According to the first aspect of the present invention, when a horizontal force in the direction perpendicular to the bridge axis acts on the superstructure, the axial end surface of the semi-annular convex portion and the wall surface of the annular groove come into contact with each other, and at the same time, the shaft of the semi-cylindrical boss portion. The direction end surface and the inner surface of the lid portion of the replacement cap come into contact with each other, and the horizontal force is transmitted to the shafts on both ends of the pin through the screwed portion between the cap and the pin. Accordingly, since the horizontal force is shared by the total of three locations of the shaft portions at both ends in addition to the reduced diameter portion at the axially intermediate portion of the pin, damage to the pin is prevented. Thereby, it is possible to improve the earthquake resistance of the existing pin support only by exchanging the cap, and the construction cost can be suppressed at a very low cost.

  According to the second aspect of the present invention, when a horizontal force perpendicular to the bridge axis acts on the superstructure, the axial end surface of the semi-annular convex portion and the wall surface of the annular groove come into contact with each other, and at the same time, exchange with the axial end surface of the rib. The end surface of the cylindrical portion of the cap abuts, and the horizontal force is transmitted to both end shaft portions of the pin through the screwed portion between the cap and the pin. Accordingly, since the horizontal force is shared by a total of three locations of the shaft portions at both ends in addition to the reduced diameter portion at the axial middle portion of the pin, damage to the pin is prevented, and the same effect as in the first aspect of the present invention is achieved. can get.

  According to the third aspect of the present invention, when a horizontal force perpendicular to the bridge axis acts on the superstructure, the axial end surface of the semi-annular convex portion and the wall surface of the annular groove come into contact with each other, and at the same time, the shaft of the semi-cylindrical boss portion. The end surface in the direction and the inner surface of the lid portion of the replacement cap abut, the end surface in the axial direction of the rib contacts the end surface of the cylindrical portion of the replacement cap, and the horizontal force is applied to the pin via the screwed portion between the cap and the pin. It is transmitted to both end shafts. Accordingly, since the horizontal force is shared by a total of three locations of the shaft portions at both ends in addition to the reduced diameter portion at the axial middle portion of the pin, damage to the pin is prevented, and the same effect as in the first aspect of the present invention is achieved. can get.

It is a vertical direction half sectional view of an existing pin bearing. It is a disassembled perspective view of the existing pin support. It is sectional drawing which shows the state which attached the cap for replacement | exchange by this invention. It is sectional drawing which exaggerates and shows a cover part inner surface.

  Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an existing pin support which is an object of earthquake resistance according to the present invention. The pin support includes an upper rod 1 fixed to the upper structure 50 and a lower rod 2 fixed to the lower structure 51. The upper collar 1 has a base 4 provided with a shear key 3 fitted into the upper structure 50. A plurality of ribs 5 are provided in the lower portion of the base 4, and semi-cylindrical boss portions 6 are provided on these ribs 5.

  The lower collar 2 has substantially the same configuration as the upper collar 1 and has a base 8 provided with a fixing portion 7 embedded in the lower structure 51. The base 8 is fixed to the lower structure 51 via anchor bolts 9. A plurality of ribs 10 are provided on the upper portion of the base 8, and semi-cylindrical boss portions 11 are provided on these ribs 10. The ribs 5 and 10 are support members that support the semi-cylindrical boss portions 6 and 11, respectively.

  The semi-cylindrical bosses 6 and 11 of the upper and lower collars 1 and 2 are arranged so that their end faces extending along the axial direction face each other, and become cylindrical as a whole, and a pin hole is formed inside. . Semi-annular convex portions 12 and 13 are provided on the inner periphery of the axially intermediate portion of these semi-cylindrical boss portions 6 and 11. These semi-annular protrusions 12 and 13 are also annular as a whole in a state where the semi-cylindrical bosses 6 and 11 are opposed to each other.

  A pin 14 is fitted on the inner periphery of the semi-cylindrical boss portions 6 and 11. An annular groove 15 is formed in the pin 14 by providing a reduced diameter portion 14 a at an intermediate portion in the axial direction, and the semi-annular convex portions 12 and 13 are fitted into the annular groove 15. The semi-cylindrical bosses 6 and 11 have a pin 14 fitted therein, and a gap 16 having a predetermined size is formed between the opposed end surfaces along the axial direction. Can be rotated. Further, when a horizontal force perpendicular to the bridge axis acts on the upper structure 50, the axial end surfaces of the semi-annular protrusions 12 and 13 abut against the wall surface of the annular groove 15, and the horizontal force is applied from the upper rod 1 via the pin 14. It is transmitted to the lower arm 2, that is, from the upper structure 50 to the lower structure 51.

  The pin 14 has a shaft portion 17 at both ends, and a cap 18 is attached to the shaft portion 17. As shown in FIG. 2, the cap 18 includes a lid portion 19 and a cylindrical portion 20 formed on the outer periphery thereof. The lid portion 19 has a mounting hole 21 for the shaft portion 17 formed in the center. The cap 18 is fixed to the shaft portion 17 by inserting the shaft portion 17 into the mounting hole 21 and screwing a nut 22 into a male screw formed in the shaft portion 17. With the cap 18 attached, the axial ends of the semicylindrical boss portions 6 and 11 are covered with the cylindrical portion 20 of the cap 18.

  In the present invention, the cap 18 is replaced with a new replacement cap in order to make the existing pin bearing earthquake resistant. As shown in FIG. 3, the basic structure of the replacement cap 30 is the same as that of the existing cap 18. That is, the replacement cap 30 is formed in a lid portion 32 having a mounting hole 31 for the shaft portion 17 of the pin 14 and a cylindrical shape formed on the outer periphery of the lid portion 32 and covering the axial ends of the semicylindrical boss portions 6 and 11. It consists of part 33.

  Although not described in the description with reference to FIGS. 1 and 2 for convenience of drawing, the axial end surfaces of the semi-annular convex portions 12 and 13 formed on the semi-cylindrical boss portions 6 and 11 and the pin 14 A gap a is formed between the wall surface of the formed annular groove 15. Further, the pin 14 slightly protrudes outward from the axial end surfaces of the semicylindrical boss portions 6, 11. Therefore, the axial end surfaces of the semicylindrical boss portions 6, 11 and the lid portion 32 of the replacement cap 30 A gap b is also formed between the inner surface. Further, a gap c is also formed between the end surface of the cylindrical portion 33 of the replacement cap 30 and the rib 5.

  These gaps a, b, and c are also formed in the existing pin support so as not to hinder the rotation of the upper collar 1, but the dimension of the gap a is the smallest in the existing pin support. For this reason, the horizontal force in the direction perpendicular to the bridge axis acting on the upper structure 50 is transmitted only when the axial end surfaces of the semi-annular convex portions 12 and 13 and the wall surface of the annular groove 15 abut, as described above. In the event of an earthquake, excessive stress is applied to the reduced diameter portion 14 a of the pin 14 that defines the annular groove 15.

  The replacement cap 30 has a lid portion 32 formed so that the dimension of the gap a is equal to the dimension of the gap b. Specifically, as shown exaggeratedly in FIG. 4, an annular step 34 is provided on the inner surface of the lid portion 32. The step 34 is a step where the inner surface portion 35 on the inner circumferential side, that is, the inner surface portion 35 that contacts the end surface of the pin 14 becomes an annular concave portion. Thereby, the dimension of the clearance gap b between the end surfaces of the semi-cylindrical boss portions 6 and 11 and the inner surface portion 36 on the outer peripheral side with respect to the step 34 opposed thereto can be made equal to the dimension of the clearance a. The dimension of the clearance a can be easily known from the design book of the existing pin support, and the inner surface of the lid portion 32 of the replacement cap 30 can be processed based on this dimension. Needless to say, the replacement cap 30 is not attached only to one end of the pin 14 but is attached to both ends.

  As shown in FIG. 3, in this embodiment, a female screw is formed in the mounting hole 31 of the replacement cap 30. The replacement cap 30 is directly fixed to the pin 14 by screwing the male screw 17a formed on the shaft portion 17 of the pin 14 to the female screw. However, like the cap 18 attached to the existing pin bearing, It may be fixed.

  According to the replacement cap 30 as described above, when a horizontal force perpendicular to the bridge axis acts on the upper structure 50, the axial end surfaces of the semi-annular protrusions 12 and 13 and the wall surface of the annular groove 15 come into contact with each other. The axial end surfaces of the semicylindrical boss portions 6 and 11 abut against the inner surface of the lid portion 32 of the replacement cap 30. As a result, the horizontal force is transmitted not only to the reduced diameter portion 14 a of the pin 14 but also to both end shaft portions 17 of the pin 14 through the screwed portion 17 a between the cap 30 and the pin 14. Therefore, since the horizontal force is shared by the total of three locations of the shaft portions 17 in addition to the reduced diameter portion 14a of the intermediate portion in the axial direction of the pin 14, damage to the pin is prevented.

  The same effect as described above can also be obtained by making the size of the gap a equal to the size of the gap c. That is, when a horizontal force perpendicular to the bridge axis acts on the upper structure 50, the axial end surfaces of the semi-annular protrusions 12 and 13 and the wall surface of the annular groove 15 come into contact with each other, and at the same time, the axial end surface of the rib 5 and the replacement cap. 30 end portions of the cylindrical portion 33 come into contact with each other. In order to achieve such a dimensional relationship, the height of the cylindrical portion 33 may be adjusted when the replacement cap 30 is processed and formed. In this case, the size of the gap b may be equal to the size of the gap a. That is, all the dimensions of the gap a, the gap b, and the gap c may be made equal.

DESCRIPTION OF SYMBOLS 1 Upper collar 2 Lower collar 4 Base 5 Rib 6 Semi-cylindrical boss part 8 Base 10 Rib 11 Semi-cylindrical boss part 12, 13 Semi-annular convex part 14 Pin 14a Reduced diameter part 15 Annular groove 17 Shaft part 18 Existing cap 30 Exchange Cap 31 Mounting hole 32 Lid 33 Cylindrical part 50 Upper structure 51 Lower structure

Claims (3)

An upper arm fixed to the upper structure, having a semi-cylindrical boss portion at the lower portion, and an axially intermediate portion inner periphery formed with a semi-annular convex portion along the circumferential direction,
A lower arm fixed to the lower structure, having a semi-cylindrical boss portion on the upper portion, and a semi-annular convex portion formed on an inner periphery in the axial direction thereof;
A pin in which the semicylindrical bosses of the upper and lower collars are respectively fitted, and an annular groove in which the semicircular projections of the upper and lower collars are fitted in the axial intermediate portion thereof is defined. A pin having a reduced diameter portion and having an axial gap formed between the axial end surface of each semi-annular convex portion and the wall surface of the annular groove;
A cap screwed to shaft portions formed at both ends of the pin, the cap portion having a mounting hole into which the shaft portion is inserted at the center, and an outer periphery of the lid portion, the cap And an existing pin support comprising a cap having a cylindrical portion covering the end of each semi-cylindrical boss portion of the lower arm,
The cap includes a dimension of an axial gap (a) between an axial end surface of the semi-annular convex portion and a wall surface of the annular groove, an axial end surface of the semi-cylindrical boss portion, and a lid portion of the cap. A method for making an existing pin bearing earthquake resistant, wherein the cap is replaced with a replacement cap formed so that the dimension of the axial clearance (b) between the inner surface and the inner surface becomes equal. An upper collar fixed to the upper structure, having a semi-cylindrical boss portion supported by a plurality of ribs at the lower portion, and a semi-annular convex portion along the circumferential direction formed on the inner periphery in the axial direction thereof With the upper arm,
A lower arm fixed to the lower structure, having a semi-cylindrical boss portion supported by a plurality of ribs on the upper portion, and a semi-annular convex portion formed on the inner periphery in the axial direction,
A pin in which the semicylindrical bosses of the upper and lower collars are respectively fitted, and an annular groove in which the semicircular projections of the upper and lower collars are fitted in the axial intermediate portion thereof is defined. A pin having a reduced diameter portion and having an axial gap formed between the axial end surface of each semi-annular convex portion and the wall surface of the annular groove;
A cap screwed into shaft portions formed at both ends of the pin, the lid portion having a mounting hole into which the shaft portion is inserted in the center, and an outer periphery of the lid portion. And an existing pin support comprising a cap having a cylindrical portion covering the end of each semi-cylindrical boss portion of the lower arm,
The cap has a dimension of an axial gap (a) between the axial end surface of the semi-annular protrusion and the wall surface of the annular groove, and an axial direction between the rib and the end surface of the cylindrical portion of the cap. A method of making an existing pin bearing seismic resistant, characterized in that it is replaced with a replacement cap formed with a cylindrical portion so that the size of the gap (c) is equal. An upper collar fixed to the upper structure, having a semi-cylindrical boss portion supported by a plurality of ribs at the lower portion, and a semi-annular convex portion along the circumferential direction formed on the inner periphery in the axial direction thereof With the upper arm,
A lower arm fixed to the lower structure, having a semi-cylindrical boss portion supported by a plurality of ribs on the upper portion, and a semi-annular convex portion formed on the inner periphery in the axial direction,
A pin in which the semicylindrical bosses of the upper and lower collars are respectively fitted, and an annular groove in which the semicircular projections of the upper and lower collars are fitted in the axial intermediate portion thereof is defined. A pin having a reduced diameter portion and having an axial gap formed between the axial end surface of each semi-annular convex portion and the wall surface of the annular groove;
A cap screwed into shaft portions formed at both ends of the pin, the lid portion having a mounting hole into which the shaft portion is inserted in the center, and an outer periphery of the lid portion. And an existing pin support comprising a cap having a cylindrical portion covering the end of each semi-cylindrical boss portion of the lower arm,
The cap includes a dimension of an axial gap (a) between an axial end surface of the semi-annular convex portion and a wall surface of the annular groove, an axial end surface of the semi-cylindrical boss portion, and a lid portion of the cap. The lid portion is formed so that the dimension of the axial clearance (b) between the inner surface and the inner surface is equal, and the axial clearance (a ) And an exchange cap formed with a cylindrical part so that the dimension of the axial gap (c) between the rib and the end face of the cylindrical part of the cap becomes equal. How to make pin bearings earthquake resistant.

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