Bridge bearing replacement method and bridge bearing structure

Abstract

To provide a bridge bearing replacement method that can be implemented regardless of the material of existing bearing members such as shoes, and that can be implemented easily. [Solution] The method for replacing the bridge bearings 1 includes: a second step ST2 in which at least one of the existing lower bearing members 17 fixed to the substructure 2 and the existing upper bearing members 18 fixed to the superstructure 3 is left in place and the one that is not left in place is removed; a third step ST3 in which a box-shaped member 29 is prepared, which comprises a bottom plate 31, side plates 32 provided on the outer circumference of the bottom plate 31, and a plurality of rib plates 33 welded to the side plates 32 and the bottom plate 31; a fourth step ST4 in which the box-shaped member 29 is positioned to cover the existing bearing members that are left in place; a fifth step ST5 in which a filler material 30 is filled inside the box-shaped member 29; and a sixth step ST6 in which rubber shoes 7 are positioned and fixed.

Description

Technical Field

[0001] The present invention relates to a method for replacing bridge bearings and a bridge bearing structure.

Background Art

[0002] After the Great Hanshin Earthquake, in order to avoid brittle failure behavior of bearings, the replacement from steel bearings to rubber pads has been carried out. In concrete bridges (including PC bridges), among the members of existing bearings, it is difficult to remove the upper pad fixed to the main girder or the anchor bar for fixing the upper pad to the superstructure, so in many cases, new bearings are installed while leaving these in place (for example, refer to the "Background Art" of Patent Document 1).

[0003] In this case, in order to effectively utilize the existing upper pad and anchor bar installed on the main girder, the existing upper pad member and the new bearing are connected and devised so as to be able to resist horizontal forces and uplift forces during an earthquake. For example, as described in Patent Document 1, a reinforcing rib may be welded to the upper pad of the remaining existing bearing, and a sole plate for a new rubber pad may be fixed to the existing upper pad through this reinforcing rib.

[0004] In Patent Document 1, a method is proposed in which not only the lower pad but also the upper pad of the existing bearing are removed and replaced with a bearing that is almost the same as when newly installed. In this method, the lower surface of the superstructure is chiseled by a predetermined thickness, the anchor bar of the upper pad of the existing bearing is partially exposed and the anchor bar is cut, and the remaining part after cutting is left so as to protrude from the chiseled part and the upper pad is removed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, with conventional methods that utilize existing upper bearings, if the existing upper bearing is made of cast iron, it is difficult to weld the reinforcing ribs to the existing upper bearing, and depending on the material of the existing upper bearing, this method may not be feasible. Furthermore, even when welding is possible, if the dimensions of the existing bearing are small and the construction space is narrow, skilled workers are required for the welding work, and quality control becomes difficult. In addition, if the positions of the existing bearing and the new bearing are significantly misaligned, the conventional method may not be applicable.

[0007] The bearing replacement method described in Patent Document 1 can solve some of these problems. However, the bearing replacement method in Patent Document 1 requires chipping away at the underside of the superstructure to which the upper shoe is fixed, and the removal of the upper shoe member is time-consuming and labor-intensive. Furthermore, in the bearing replacement method in Patent Document 1, the upper surface of the substructure is similarly chipped away in order to remove the lower shoe and the base plate that supports it. Although the removal of the lower shoe is easier than the removal of the upper shoe, the work still requires a great deal of time and labor.

[0008] In view of the above background, the present invention aims to provide a bridge bearing replacement method and a bridge bearing structure that can be implemented regardless of the material of existing bearing members such as shoes, and that can be implemented easily. [Means for solving the problem]

[0009] To solve the above problems, one aspect of the present invention is a method for replacing the bearings of a bridge (1), comprising: a first step (ST1) of supporting the superstructure of the bridge with jacks supported on the substructure (2) of the bridge; a second step (ST2) of leaving at least one of the existing bearing members (18, 65) among the existing lower bearing members (17, 65) fixed to the substructure and the existing upper bearing member (18) fixed to the superstructure and supported by the existing lower bearing member, and removing the existing bearing member (17) if there is an existing bearing member that is not left; and a box-shaped member (29) comprising a bottom plate (31), a side plate (32) provided on the outer circumference of the bottom plate, and a plurality of rib plates (33) welded to the side plate and the bottom plate. The process includes a third step (TS3), a fourth step (ST4) in which the box-shaped member is positioned to cover the existing support member to be left in place, and if there is an existing support member that is not left in place, a new plate-shaped member (26) to replace the removed existing support member is fixed to the corresponding lower structure or upper structure, a fifth step (ST5) in which a filler material (30) is filled inside the box-shaped member to enable the transmission of horizontal force and the box-shaped member is fixed to the corresponding lower structure or upper structure, a sixth step (ST6) in which a rubber shoe (7) is positioned between the two box-shaped members, or between the box-shaped member and the plate-shaped member, and the rubber shoe is fixed to the upper and lower box-shaped members or plate-shaped member, and a seventh step (ST7) in which the jack is retracted and the rubber shoe supports the upper structure.

[0010] In this embodiment, the rib plate is welded to the bottom plate and side plate, eliminating the need to weld the rib plate to the existing bearing member. Therefore, this method can be implemented regardless of the material of the existing bearing member, such as the shoe. Furthermore, since at least one of the existing bearing members is left in place, the removal of the existing bearing member is easy, and the bearing replacement method is simplified.

[0011] In the above embodiment, the third step may be performed at a location other than the installation location of the box-shaped member.

[0012] According to this embodiment, since it is not necessary to weld multiple rib plates to the side plate and bottom plate in a confined space, variations in quality can be suppressed.

[0013] In the above embodiment, the fourth and fifth steps may be performed by fixing the box-shaped member, which is positioned to cover the remaining existing support member, with a plurality of newly installed anchors (28, 24) provided on the corresponding lower structure or upper structure and the filling material.

[0014] According to this embodiment, the box-shaped member can be fixed to the substructure or superstructure via a newly installed anchor so that it can transmit upward force.

[0015] In the above embodiment, the fourth step may involve providing the multiple newly installed anchors in the corresponding substructure or superstructure, and then forming fixing through holes (31b) in the bottom plate according to the positions of the newly installed anchors.

[0016] According to this embodiment, a new anchor can be installed in the substructure or superstructure without damaging the reinforcing bars embedded in the substructure or superstructure.

[0017] In the above embodiment, the fourth step may involve fixing the plate-shaped member to the corresponding substructure using the multiple existing anchors (19) that were used to fix the removed existing support member.

[0018] According to this embodiment, the plate-shaped member can be fixed to the substructure in a way that allows the lifting force to be transmitted using existing anchors.

[0019] In the above embodiment, the fourth step may involve fixing the plate-shaped member with a plurality of newly installed anchors (24) provided on the corresponding substructure or superstructure.

[0020] According to this embodiment, the new anchor can bear the horizontal and upward forces that are insufficient for the existing anchor, and the plate-shaped member can be fixed to the substructure or superstructure with high bonding strength.

[0021] In the above aspect, in the fourth step, after providing the plurality of new anchors to the corresponding substructure or superstructure, it is preferable to form a through-hole for fixing (31b) in the plate-like member according to the position of the new anchor.

[0022] According to this aspect, the new anchor can be provided to the substructure or superstructure without damaging the reinforcing bars embedded in the substructure or superstructure.

[0023] Further, in order to solve the above problems, another aspect of the present invention is a support structure (4, 54) of a bridge (1), including a lower support structure (5, 55) fixed to a substructure (2) of the bridge, an upper support structure (6) fixed to a superstructure (3) of the bridge and supported by the lower support structure, and a rubber pad (7) interposed between the lower support structure and the upper support structure and fixed to the lower support structure and the upper support structure. At least one of the lower support structure and the upper support structure includes an existing support member (18) fixed to the corresponding substructure or superstructure by a plurality of existing anchors (20), a bottom plate (31) disposed opposite to the existing support member, a side plate (32) provided at an outer peripheral portion of the bottom plate, and a plurality of rib plates (33) welded to the side plate and the bottom plate, a box-shaped member (29) disposed to cover the existing support member, and a filler (30) filled inside the box-shaped member.

[0024] According to this aspect, the rib plate is welded to the bottom plate and the side plate and is not welded to the existing support member. Therefore, regardless of the material of the existing support member such as the pad, the support structure can be provided to the substructure or superstructure so as to be able to transmit a predetermined horizontal force. Further, since at least one existing support member such as the pad is left, the removal work of the existing support member at the time of support replacement is easy.

[0025] In the above aspect, at least one of the lower support structure and the upper support structure may further include a plurality of newly installed anchors (28, 24) for fixing the box-shaped member to the corresponding lower structure or upper structure.

[0026] According to this aspect, the box-shaped member can be fixed to the lower structure or the upper structure through the newly installed anchors so as to be capable of transmitting the uplifting force.

[0027] In the above aspect, it is preferable that the plurality of newly installed anchors are arranged on the outer peripheral portion of the bottom plate corresponding to the rib plate.

[0028] According to this aspect, the transmission performance of the horizontal force of the box-shaped member, particularly the transmission performance of the rotational force in the horizontal direction, is improved.

[0029] In the above aspect, it is preferable that the lower support structure or the upper support structure is fixed to the corresponding lower structure or upper structure by a plurality of existing anchors (19) and includes a plate-shaped member (26) to which the rubber sole is fixed.

[0030] According to this aspect, the plate-shaped member can be fixed to the lower structure or the upper structure while maintaining the transmission characteristics of the horizontal force and the uplifting force by the existing anchors.

Effect of the Invention

[0031] According to the above aspects, it is possible to provide a method for replacing a bridge support and a bridge support structure that can be constructed regardless of the material of an existing support member such as a sole and can be easily constructed.

Brief Description of the Drawings

[0032] [Figure 1] Front view of the bridge support structure according to the first embodiment [Figure 2] Front view of the existing support structure before replacing the bridge support according to the first embodiment [Figure 3] Plan view of the plate-shaped member [Figure 4] Plan view of the box-shaped member [Figure 5] A flowchart showing the procedure for bearing replacement work. [Figure 6] Front view of the bearing structure during bearing replacement. [Figure 7] Front view of the bearing structure during bearing replacement. [Figure 8] Front view of the bearing structure during bearing replacement. [Figure 9] Front view of the bearing structure during bearing replacement. [Figure 10] Front view of the bearing structure during bearing replacement. [Figure 11] Front view of the bridge bearing structure according to the second embodiment [Figure 12] Side view of the existing bridge bearing structure before bearing replacement according to the second embodiment. [Modes for carrying out the invention]

[0033] Embodiments of the present invention will be described in detail below with reference to the drawings. ≪First Embodiment≫

[0034] First, a first embodiment of the present invention will be described with reference to Figures 1 to 10. Figure 1 is a front view of the support structure 4 of a bridge 1 according to the first embodiment. As shown in Figure 1, the bridge 1 has a substructure 2, a superstructure 3, and a support structure 4 for supporting the superstructure 3 on the substructure 2. The support structure 4 is newer than the substructure 2 and superstructure 3, and is a refurbished structure whose supports have been replaced by a support replacement method described later. Although only one support structure 4 is shown in Figure 1, the superstructure 3 is supported by multiple support structures 4.

[0035] Substructure 2 is a bridge pier or abutment and is made of reinforced concrete (RC). RC typically refers to a reinforced concrete structure. However, in this specification, RC may also refer to a concrete structure reinforced with reinforcing bars other than steel bars, or a concrete structure reinforced with steel frames, fiber reinforcement, tensioning members, etc.

[0036] The superstructure 3 is a so-called bridge girder, and has a girder section and a deck section (not shown). In this embodiment, both the girder section and the deck section are made of reinforced concrete (RC). In other embodiments, the girder section may be made of steel (S).

[0037] The support structure 4 includes a lower support structure 5 fixed to the lower structure 2, an upper support structure 6 fixed to the upper structure 3, and a rubber shoe 7 interposed between the lower support structure 5 and the upper support structure 6. The rubber shoe 7 comprises a rubber support 8, a lower shoe 9 attached to the lower surface of the rubber support 8, and an upper shoe 10 attached to the upper surface of the rubber support 8. The rubber support 8 has a laminated structure of steel plate and rubber, and supports vertical loads while allowing horizontal displacement due to deformation. The rubber support 8 may also be equipped with damping members such as lead plugs. The lower shoe 9 and upper shoe 10 are made of steel plates and are configured to be fixable by fixing bolts 11. The rubber support 8 is fixed to the lower support structure 5 and the upper support structure 6 via the lower shoe 9 and the upper shoe 10. In this way, the upper support structure 6 is supported by the lower support structure 5 so as to be movable in the horizontal direction via the rubber shoe 7.

[0038] In this embodiment, the lower support structure 5 incorporates a portion of the existing support structure 14 before its replacement as a structural element. Similarly, the upper support structure 6 also incorporates a portion of the existing support structure 14 before its replacement as a structural element. Therefore, before describing the details of the support structure 4 in this embodiment, we will first describe the existing support structure 14 before its replacement.

[0039] Figure 2 is a front view of the existing bearing structure 14 of the bridge 1 according to the first embodiment before bearing replacement. As shown in Figure 2, the existing bearing structure 14 in this embodiment is a pin bearing structure made of steel. The existing bearing structure 14 does not have to be a pin bearing structure; it may be a steel bearing structure such as a pin roller bearing structure, a line bearing structure, a bearing plate bearing structure, or a pivot bearing structure. Since the existing bearing structure 14 is a steel bearing structure, it has brittle fracture characteristics and is structurally converted to a rubber bearing 8 equipped with a rubber shoe 7 as shown in Figure 1.

[0040] The existing support structure 14 comprises an existing height adjustment section 15 constructed on the substructure 2, and an existing pin support 16 fixed to the existing height adjustment section 15 and the superstructure 3. The existing height adjustment section 15 may be made of, for example, non-shrink mortar. The existing pin support 16 comprises an existing lower support member 17 and an existing upper support member 18. The existing lower support member 17 is fixed to the substructure 2 and the existing height adjustment section 15 by a plurality of existing anchor bolts 19 embedded in them. The existing upper support member 18 is fixed to the superstructure 3 by a plurality of existing anchor bars 20 embedded in the superstructure 3.

[0041] A pin (not shown) is interposed between the existing lower support member 17 and the existing upper support member 18, and the existing upper support member 18 is rotatable around the pin axis relative to the existing lower support member 17. The existing lower support member 17 and the existing upper support member 18 are connected to each other by a pair of caps 21 provided at both ends of the pin, thereby enabling the transmission of upward force.

[0042] Returning to Figure 1, we continue the explanation of the bearing structure 4 after the bearing replacement. The lower bearing structure 5 comprises several existing anchor bolts 19 from the existing bearing structure 14, several newly installed lower anchor bolts 24, a height adjustment section 25, and a plate-shaped member 26. The existing anchor bolts 19 have their upper ends at a lower position compared to the state before the bearing replacement shown in Figure 2.

[0043] Multiple newly installed lower anchor bolts 24 are embedded in the substructure 2 and the height adjustment section 25, and protrude upward from the upper surface of the height adjustment section 25. Male threads are formed on the protruding upper ends of the lower anchor bolts 24. The multiple lower anchor bolts 24 are arranged on the outer circumference of the rubber shoe 7, and nuts 27 are screwed onto them to fix the plate-shaped member 26 to the substructure 2 and the height adjustment section 25, enabling the transmission of upward and horizontal forces.

[0044] The height adjustment section 25 is newly constructed on the upper surface of the substructure 2 to adjust the height of the plate-shaped member 26. The height adjustment section 25 may be made of, for example, non-shrink mortar. The plate-shaped member 26 is a steel base plate that supports the rubber shoe 7.

[0045] Figure 3 is a plan view of the plate-shaped member 26. As shown in Figure 3, the plate-shaped member 26 has multiple fixing holes 26a for lower shoes, multiple fixing holes 26b for lower anchors, and multiple fixing holes 26c for existing anchors.

[0046] The lower shoe fixing holes 26a are holes for fixing the lower shoe 9 of the rubber shoe 7, and in this embodiment, they are made up of screw holes into which the fixing bolt 11 (see Figure 1) is screwed. The lower shoe fixing holes 26a are evenly distributed along the outer circumference of the lower shoe 9.

[0047] The lower anchor fixing holes 26b are holes for fixing the lower anchor bolts 24, and in this embodiment, they are through holes through which the lower anchor bolts 24 can be inserted. In this embodiment, the lower anchor fixing holes 26b are formed in a total of four locations, two at the front and two at the back on both the left and right sides of the rubber shoe 7. These lower anchor fixing holes 26b are formed in the plate-shaped member 26 according to the actual positions of the lower anchor bolts 24 after the four lower anchor bolts 24 (Figure 1) have been attached to the substructure 2.

[0048] The existing anchor fixing holes 26c are holes for fixing existing anchor bolts 19, and in this embodiment, they consist of a through hole with a larger diameter than the existing anchor bolt 19 and a groove for welding formed in a mortar shape at the top of the through hole (see Figure 9). In this embodiment, the existing anchor bolts 19 (Figure 1) are provided in a total of six locations: three in the left-right direction and two in the front-back direction. Six existing anchor fixing holes 26c are formed in corresponding positions on the plate-shaped member 26 according to the positions of these existing anchor bolts 19.

[0049] As shown in Figure 1, the upper support structure 6 includes multiple existing anchor bars 20 and existing upper support members 18 of the existing support structure 14. The upper support structure 6 also includes multiple newly installed upper anchor bolts 28, a box-shaped member 29 positioned to cover the existing support members, and a filling material 30 filled inside the box-shaped member 29. In other words, these existing anchor bars 20 and existing upper support members 18 of the existing support structure 14 are left in place without being removed. The existing upper support members 18 are existing support members fixed to the superstructure 3 by multiple existing anchor bars 20.

[0050] The box-shaped member 29 comprises a bottom plate 31 (sole plate) positioned opposite the existing upper support member 18, side plates 32 provided on the outer circumference of the bottom plate 31, and a plurality of rib plates 33 welded to the side plates 32 and the bottom plate 31. The bottom plate 31 is a steel plate with a lower surface supported by a rubber shoe 7. The side plates 32 are provided around the entire circumference of the bottom plate 31. The side plates 32 are used as formwork for the filler material 30. The plurality of rib plates 33 increase the support rigidity of the side plates 32 relative to the bottom plate 31, thereby improving the rigidity of the box-shaped member 29.

[0051] The newly installed upper anchor bolts 28 are embedded in the superstructure 3 and the filler material 30, and protrude downward from the lower surface of the bottom plate 31. Male threads are formed on the protruding lower ends of the upper anchor bolts 28. The multiple upper anchor bolts 28 are arranged on the outer circumference of the rubber shoe 7, and nuts 27 are screwed onto them to fix the bottom plate 31 of the box-shaped member 29 to the superstructure 3, enabling the transmission of upward force.

[0052] Figure 4 is a plan view of the box-shaped member 29. As shown in Figure 4, the bottom plate 31 of the box-shaped member 29 has a plurality of upper shoe fixing holes 31a and a plurality of upper anchor fixing holes 31b for newly installed anchors.

[0053] The upper shoe fixing holes 31a are holes for fixing the upper shoe 10 of the rubber shoe 7, and in this embodiment, they are threaded holes into which fixing bolts 11 (see Figure 1) are screwed. The upper shoe fixing holes 31a are evenly distributed along the outer circumference of the upper shoe 10.

[0054] The upper anchor fixing holes 31b are holes for fixing newly installed upper anchor bolts 28, and in this embodiment, they are through holes through which the upper anchor bolts 28 can be inserted. In this embodiment, the upper anchor fixing holes 31b are formed in a total of six locations, three in different positions in the front-to-back direction on both the left and right sides of the rubber shoe 7. These upper anchor fixing holes 31b are formed in the bottom plate 31 according to the actual positions of the upper anchor bolts 28 after the four upper anchor bolts 28 have been attached to the superstructure 3.

[0055] The filler material 30 (Figure 1) is filled between the bottom plate 31 and the superstructure 3 in order to fix the box-shaped member 29 to the superstructure 3 while adjusting the height of the box-shaped member 29. The filler material 30 may be, for example, non-shrink mortar. The upper edge of the box-shaped member 29 is positioned slightly below the lower surface of the superstructure 3, and a formwork (not shown) is placed to close the gap between the upper edge of the box-shaped member 29 and the lower surface of the superstructure 3 when the filler material 30 is filled. As the filler material 30 is filled inside the box-shaped member 29, the box-shaped member 29 is connected to the existing upper support member 18 so that it can transmit horizontal forces. In this way, the box-shaped member 29 is fixed to the superstructure 3 via the existing upper support member 18.

[0056] Next, with reference to Figures 5 to 10, the procedure for the bridge bearing replacement method according to the embodiment will be described.

[0057] Figure 5 is a flowchart showing the procedure for the bearing replacement method. As shown in Figure 5, the bearing replacement method comprises a first step ST1 in which the superstructure 3 of the bridge 1 is jacked up, and a second step ST2 in which a part of the existing bearing structure 14 is removed. The bearing replacement method also comprises a third step ST3 in which a box-shaped member 29 and a plate-shaped member 26 are prepared, and a fourth step ST4 in which the box-shaped member 29 is positioned and the plate-shaped member 26 is fixed. The bearing replacement method also comprises a fifth step ST5 in which a filler material 30 is filled inside the box-shaped member 29, and a sixth step ST6 in which the rubber bearing 8 is fixed. Furthermore, the bearing replacement method comprises a seventh step ST7 in which the superstructure 3 is jacked down.

[0058] The following describes each process in detail with reference to Figures 6 to 10. Figures 6 to 10 are front views of the bearing structure 4 during bearing replacement. Each process is performed by a worker.

[0059] As shown in Figure 6, in the first step ST1, the worker supports the upper structure 3 (jacking up) by supporting a jack (not shown) on the lower structure 2 and extending the jack. The jack may be placed directly on the upper surface of the lower structure 2, on a stand placed on the upper surface of the lower structure 2, or on a bracket attached to the lower structure 2.

[0060] In the second step, ST2, the worker removes the existing height adjustment section 15, the existing lower support member 17, the cap 21 and the pin, which are fixed to the substructure 2, and leaves the existing upper support member 18 fixed to the superstructure 3 in place. The existing anchor bolts 19 fixed to the substructure 2 are also left in place.

[0061] In the third step, ST3, the worker prepares the plate-shaped member 26 shown in Figure 3 and the box-shaped member 29 shown in Figure 4. The plate-shaped member 26 and the box-shaped member 29 are manufactured in the factory.

[0062] As an initial step of the fourth process ST4, which involves fixing the box-shaped member 29 and the plate-shaped member 26, the worker fixes a plurality of lower anchor bolts 24 to the substructure 2 and a plurality of upper anchor bolts 28 to the superstructure 3, as shown in Figure 7. Specifically, the worker uses a drilling machine such as a hammer drill or core drill to form a plurality of anchor insertion holes in the upper surface of the substructure 2 and the lower surface of the superstructure 3. The worker inserts either the lower anchor bolts 24 or the upper anchor bolts 28 into each anchor insertion hole and allows the adhesive or grout filled in the anchor insertion hole to harden. This fixes the lower anchor bolts 24 to the substructure 2 and the upper anchor bolts 28 to the superstructure 3.

[0063] Subsequently, the worker constructs a height adjustment section 25 on the upper surface of the substructure 2, as shown in Figure 8. The height adjustment section 25 is a support base for the plate-shaped member 26 (Figure 1). Each lower anchor bolt 24 has a length that protrudes upward from the upper surface of the height adjustment section 25 with a dimension greater than the thickness of the plate-shaped member 26. Meanwhile, the worker cuts each existing anchor bolt 19 to a predetermined height. The cutting position of the existing anchor bolt 19 is at a position above the upper surface of the height adjustment section 25 by the thickness of the plate-shaped member 26, or slightly below that position.

[0064] After the lower anchor bolt 24 is fixed to the substructure 2, the worker accurately measures the position of the lower anchor bolt 24 and the position of the existing anchor bolt 19, and forms the lower anchor fixing hole 26b and the existing anchor fixing hole 26c in the plate-shaped member 26 at the corresponding positions. Similarly, after the upper anchor bolt 28 is fixed to the superstructure 3, the worker accurately measures the position of the upper anchor bolt 28, and forms the upper anchor fixing hole 31b in the bottom plate 31 at the corresponding position. The lower anchor fixing hole 26b, the existing anchor fixing hole 26c, and the upper anchor fixing hole 31b may be processed at the factory where the plate-shaped member 26 and the box-shaped member 29 were manufactured, or they may be processed at the yard after they have been delivered to the material yard on site.

[0065] Subsequently, as the main task of the fourth step ST4, the worker positions the plate-shaped member 26 at a predetermined position above the height adjustment section 25, as shown in Figure 9. At this time, the lower anchor bolt 24 is inserted into the lower anchor fixing hole 26b, and the existing anchor bolt 19 is inserted into the existing anchor fixing hole 26c. The worker fixes the lower anchor bolt 24 to the plate-shaped member 26 by screwing the nut 27 onto the lower anchor bolt 24, and fixes the existing anchor fixing hole 26c to the plate-shaped member 26 by welding at the groove of the existing anchor fixing hole 26c. In this way, the plate-shaped member 26 is fixed to the substructure 2.

[0066] Furthermore, the worker positions the box-shaped member 29 at a predetermined location below the superstructure 3 so as to cover the existing upper support member 18. At this time, the upper anchor bolt 28 is inserted into the upper anchor fixing hole 31b. The worker adjusts the height position of the box-shaped member 29 by screwing the nut 27 onto the upper anchor bolt 28, and then supports the box-shaped member 29 on the upper anchor bolt 28.

[0067] Subsequently, in the fifth step ST5, the worker seals the gap between the upper edge of the box-shaped member 29 and the lower surface of the superstructure 3 with a formwork and fills the inside of the box-shaped member 29 with filler material 30. The filler material 30 is injected into the box-shaped member 29 until it reaches the lower surface of the superstructure 3. As the filler material 30 hardens, the box-shaped member 29 is fixed to the lower surface of the superstructure 3.

[0068] Subsequently, in the sixth step ST6, the worker places the rubber shoe 7 in a predetermined position between the box-shaped member 29 and the plate-shaped member 26, as shown in Figure 10. Note that although Figure 10 shows the rubber shoe 7 sliding perpendicular to the bridge axis and being inserted between the box-shaped member 29 and the plate-shaped member 26, in reality it slides in the direction of the bridge axis and is inserted between the box-shaped member 29 and the plate-shaped member 26. After placing the rubber shoe 7, the worker tightens the fixing bolts 11 (see Figure 1) to fix the lower shoe 9 and upper shoe 10 to the bottom plate 31 of the plate-shaped member 26 and the box-shaped member 29.

[0069] Furthermore, in the seventh step ST7, the worker shortens the jack (not shown) that was supporting the superstructure 3, thereby lowering the superstructure 3 (jacking down). In parallel with the lowering of the superstructure 3, the worker further tightens the fixing bolts 11 that were tightened in the sixth step ST6. With this, the bearing replacement method is completed, and the bearing structure 4 shown in Figure 1 is constructed.

[0070] Thus, in this embodiment, the method for replacing the bridge bearings 1 includes the first step ST1 to the seventh step ST7 described above. In the fourth step ST4, as shown in Figure 9, a box-shaped member 29 is positioned to cover the remaining existing upper bearing member 18, and a filler material 30 is filled inside the box-shaped member 29, thereby fixing the box-shaped member 29 to the superstructure 3 so that horizontal forces can be transmitted. The rib plates 33 of the box-shaped member 29 are welded to the bottom plate 31 and the side plates 32, but not to the existing upper bearing member 18. Therefore, this method can be implemented regardless of the material of the existing upper bearing member 18. In addition, since the existing upper bearing member 18, existing anchor bars 20, and existing anchor bolts 19 are left in place, the removal of these existing bearing members is easy, and the replacement of the bearings is easy.

[0071] The third step ST3, which involves preparing the box-shaped member 29, is performed in a location other than the factory, i.e., the installation location of the box-shaped member 29. Therefore, since there is no need to weld multiple rib plates 33 to the side plates 32 and bottom plate 31 in a confined space, variations in quality are suppressed.

[0072] In the fourth step ST4 and fifth step ST5 shown in Figure 9, a box-shaped member 29, positioned to cover the remaining existing upper support member 18, is fixed to the superstructure 3 by a plurality of newly installed upper anchor bolts 28 and filler material 30. As a result, the box-shaped member 29 is fixed to the superstructure 3 so that it can transmit upward lifting force via the upper anchor bolts 28.

[0073] In the fourth step, ST4, as shown in Figure 8, multiple new upper anchor bolts 28 are installed in the superstructure 3, and then upper anchor fixing holes 31b (Figure 4) are formed in the bottom plate 31 shown in Figure 9 according to the positions of the upper anchor bolts 28. Therefore, the new upper anchor bolts 28 can be installed in the superstructure 3 without damaging the reinforcing bars embedded in the superstructure 3.

[0074] As shown in Figures 8 and 9, in the fourth step ST4, the plate-shaped member 26 is fixed to the substructure 2 using multiple existing anchor bolts 19 that were used to fix the removed existing lower support member 17. Therefore, the plate-shaped member 26 is fixed to the substructure 2 in a way that allows the upward force to be transmitted using the existing anchor bolts 19. This makes it possible to reduce the number, anchoring length, and thickness of the newly installed lower anchor bolts 24.

[0075] In the fourth step, ST4, the plate-shaped member 26 is fixed to the substructure 2 by a plurality of newly installed lower anchor bolts 24. As a result, the newly installed lower anchor bolts 24 bear the horizontal and upward forces that are insufficient for the existing anchor bar 20, and the plate-shaped member 26 is fixed to the substructure 2 with high bonding strength.

[0076] In the fourth step ST4, after installing multiple newly installed lower anchor bolts 24 in the substructure 2, upper anchor fixing holes 31b are formed in the plate-shaped member 26 according to the positions of the newly installed lower anchor bolts 24. Therefore, the newly installed lower anchor bolts 24 can be installed in the substructure 2 without damaging the reinforcing bars embedded in the substructure 2.

[0077] Furthermore, the bearing structure 4 of this embodiment, in which the bearing has been replaced in this manner, provides the following effects. Specifically, as shown in Figure 1, the upper bearing structure 6 comprises an existing upper bearing member 18 fixed to the superstructure 3, a box-shaped member 29 arranged to cover the existing upper bearing member 18, and a filling material 30 filled inside the box-shaped member 29. With this configuration, the upper bearing structure 6 is fixed to the superstructure 3 so as to be able to transmit horizontal force and upward force. The box-shaped member 29 comprises a bottom plate 31 positioned opposite the existing upper bearing member 18, side plates 32 provided on the outer circumference of the bottom plate 31, and a plurality of rib plates 33 welded to the side plates 32 and the bottom plate 31. In other words, the rib plates 33 are welded only to the bottom plate 31 and the side plates 32, and not to the existing upper bearing member 18. Therefore, regardless of the material of the existing upper bearing member 18, the bearing structure 4 can be installed on the superstructure 3 so as to be able to transmit a predetermined horizontal force. Furthermore, since the existing upper support member 18 is left in place, the removal of the existing support member when replacing the support is easy.

[0078] Furthermore, the upper support structure 6 of this embodiment is further equipped with a plurality of newly installed upper anchor bolts 28 for fixing the box-shaped member 29 to the superstructure 3. Therefore, the box-shaped member 29 is fixed to the superstructure 3 via the newly installed upper anchor bolts 28 so that it can transmit upward lifting force.

[0079] As shown in Figure 4, the multiple newly installed upper anchor bolts 28 are positioned on the outer circumference of the bottom plate 31, which corresponds to the rib plate 33. This improves the horizontal force transmission performance of the box-shaped member 29, particularly the horizontal rotational force transmission performance.

[0080] As shown in Figure 1, the lower support structure 5 is fixed to the substructure 2 by a plurality of existing anchor bolts 19 and includes a plate-shaped member 26 to which the rubber shoe 7 is fixed. Therefore, the plate-shaped member 26 is fixed to the substructure 2 while maintaining the transmission characteristics of horizontal force and upward force by the existing anchor bolts 19. This makes it possible to reduce the number, anchoring length, and thickness of the newly installed lower anchor bolts 24. ≪Second Embodiment≫

[0081] Next, a second embodiment of the present invention will be described with reference to Figures 11 and 12. Hereinafter, the same or similar components as in the first embodiment will be denoted by the same reference numerals, and redundant descriptions will be omitted.

[0082] Figure 11 is a front view of the support structure 54 of the bridge 1 according to the second embodiment. As shown in Figure 11, the support structure 54 of this embodiment differs from the first embodiment in the configuration of the lower support structure 55. Specifically, the lower support structure 55 has a box-shaped member 29 instead of a plate-shaped member 26. In addition, the lower support structure 55, as part of the existing support structure 14 before the support replacement which is included as a structural element, has a plurality of existing anchor bolts 19 as in the first embodiment, as well as an existing bottom plate 65. Before describing the details of the support structure 54 of this embodiment, the existing support structure 64 before the support replacement will be described.

[0083] Figure 12 is a side view of the existing bearing structure 64 of bridge 1 before bearing replacement according to the second embodiment. As shown in Figure 12, the existing bearing structure 64 in this embodiment is a pin roller bearing structure made of steel. Because the existing bearing structure 64 is a steel bearing structure, it has brittle fracture characteristics and will be structurally converted to a rubber bearing 8 equipped with a rubber shoe 7 as shown in Figure 11.

[0084] The existing support structure 64 comprises an existing steel base plate 65 fixed to the substructure 2, and an existing pin support 16 supported on the existing base plate 65 via a plurality of rollers 66 so as to be movable in the bridge axis direction, and fixed to the superstructure 3. The existing base plate 65 is fixed to the substructure 2 by existing anchor bolts 19. The existing pin support 16 comprises an existing lower support member 17 and an existing upper support member 18. The existing lower support member 17 is supported on the existing base plate 65 via a plurality of rollers 66.

[0085] A pin 22 is interposed between the existing lower support member 17 and the existing upper support member 18, and the existing upper support member 18 is rotatable around the pin axis relative to the existing lower support member 17. The existing lower support member 17 and the existing upper support member 18 are connected to each other by a pair of caps 21 provided at both ends of the pin.

[0086] Returning to Figure 11, we continue the explanation of the bearing structure 54 after the bearing replacement. The lower bearing structure 55 comprises multiple existing anchor bolts 19 and an existing bottom plate 65 from the existing bearing structure 14. The lower bearing structure 55 also comprises multiple newly installed lower anchor bolts 24, a box-shaped member 29 positioned to cover the existing bottom plate 65 which is an existing bearing member, and a filling material 30 filled inside the box-shaped member 29. In other words, of the existing bearing structure 64, in addition to the existing anchor bar 20 and existing upper bearing member 18 fixed to the upper structure 3, and the existing anchor bolts 19 fixed to the lower structure 2, the existing bottom plate 65 is also left in place without being removed. The existing bottom plate 65 is an existing bearing member fixed to the lower structure 2 by multiple existing anchor bolts 19.

[0087] The box-shaped member 29 of the lower support structure 5, which is positioned to cover the existing bottom plate 65, has the same configuration as the box-shaped member 29 of the upper support structure 6, which is positioned to cover the existing upper support member 18, and is positioned in a direction that is vertically symmetrical to the box-shaped member 29 of the upper support structure 6.

[0088] The construction procedure for the lower support structure 5 is the same as the construction procedure for the upper support structure 6 described in the first embodiment. That is, referring to Figure 5, the fourth step ST4, in which a box-shaped member 29 is placed and a plate-shaped member 26 is fixed, becomes a step in which two box-shaped members 29 are placed, since no plate-shaped member 26 is used. In the fifth step ST5, the inside of the two box-shaped members 29 is filled with filler material 30.

[0089] Thus, in the fourth step ST4, as shown in Figure 11, a box-shaped member 29 is positioned to cover the remaining existing bottom plate 65, and a filler material 30 is filled inside the box-shaped member 29, thereby fixing the box-shaped member 29 to the substructure 2 so that horizontal forces can be transmitted. The rib plates 33 of the box-shaped member 29 are welded to the bottom plate 31 and the side plates 32, but not to the existing upper support member 18. Therefore, this construction method can be implemented regardless of the material of the existing bottom plate 65. In addition, since the existing upper support member 18, existing anchor bars 20, and existing anchor bolts 19 are left in place, the removal of these existing support members is easy, and the replacement of the support is also easy.

[0090] Furthermore, in the second step ST2 shown in Figure 5, in which a portion of the existing support structure 14 is removed, the worker removes the existing lower support member 17, which includes the multiple rollers 66 supported by the existing bottom plate 65 and the caps 21 and pins 22, from the existing support structure 14 shown in Figure 12. On the other hand, the worker leaves in place the existing bottom plate 65 fixed to the lower structure 2 and the existing upper support member 18 fixed to the upper structure 3.

[0091] The bearing structure 54 of this embodiment, in which bearing replacement is performed in this manner, has the following effects. Specifically, as shown in Figure 11, the lower bearing structure 5 comprises an existing upper bearing member 18 fixed to the lower structure 2, a box-shaped member 29 positioned to cover the existing upper bearing member 18, and a filling material 30 filled inside the box-shaped member 29. With this configuration, the lower bearing structure 55 is fixed to the lower structure 2 so as to be able to transmit horizontal force and upward force. Furthermore, the rib plate 33 of the box-shaped member 29 is welded only to the bottom plate 31 and the side plate 32, and is not welded to the existing bottom plate 65. Therefore, the bearing structure 54 can be installed on the lower structure 2 so as to be able to transmit a predetermined horizontal force regardless of the material of the existing bottom plate 65. In addition, since the existing bottom plate 65 is left in place, the removal of the existing bearing member when replacing the bearing is easy.

[0092] This concludes the description of specific embodiments, but the present invention is not limited to the above embodiments or modifications and can be broadly modified and implemented.

[0093] For example, in the first embodiment, the lower support structure 5 of the support structure 4 includes a plate-shaped member 26 that transmits horizontal force via existing anchor bolts 19 and newly installed lower anchor bolts 24. On the other hand, the upper support structure 6 includes a box-shaped member 29 that transmits horizontal force via existing support members (existing upper support members 18). In other embodiments, the upper support structure 6 may also include a plate-shaped member 26 that transmits horizontal force via existing anchor bars 20 and newly installed upper anchor bolts 28. In this case, the lower support structure 5 includes a box-shaped member 29 that transmits horizontal force via existing support members (existing lower support members 17 or existing bottom plate 65).

[0094] In addition, the specific configuration, arrangement, quantity, and materials of each component and part, as well as the specific operations and sequence of each operation, can be modified as appropriate, as long as they do not depart from the spirit of the present invention. Furthermore, not all of the components shown in the above embodiments are necessarily essential, and can be selected as appropriate. [Explanation of Symbols]

[0095] 1: Bridge 2: Substructure 3:Superstructure 4:Support structure 5: Lower support structure 6: Upper support structure 7: Rubber shoes 8: Rubber bearing 9: Lower shoe 10: Kamikutsu 14: Existing support structure 16: Existing pin bearing 17: Existing lower support member (existing support member) 18: Existing upper support member (existing support member) 19: Existing anchor bolts (existing anchors) 20: Existing anchor bar (existing anchor) 24: Lower anchor bolt (newly installed anchor) 25: Height adjustment section 26: Plate-shaped member 28: Upper anchor bolt (newly installed anchor) 29: Box-shaped member 30: Filling material 31: Bottom plate 31b: Fixing hole for upper anchor 32: Side plate 33: Rib Plate 54:Support structure 55: Lower support structure 64: Existing bearing structure 65: Existing base plate ST1: 1st process ST2: 2nd process ST3: 3rd process ST4: 4th process ST5: 5th process ST6: 6th process ST7: 7th process

Claims

1. A bridge bearing replacement method, The first step involves supporting the superstructure of the bridge with jacks supported by the substructure of the bridge, A second step is to leave at least one of the existing support members, which is fixed to the substructure and the existing upper support member, which is fixed to the superstructure and supported by the existing lower support member, and to remove any existing support members that are not left in place. A third step is to prepare a box-shaped member comprising a bottom plate, side plates provided on the outer circumference of the bottom plate, and a plurality of rib plates welded to the side plates and the bottom plate, A fourth step involves arranging the box-shaped member so as to cover the existing support member that is to be left in place, and if there is an existing support member that is not to be left in place, fixing a new plate-shaped member to replace the removed existing support member to the corresponding lower structure or upper structure. A fifth step involves filling the inside of the box-shaped member with a filler material to enable the transmission of horizontal force, and fixing the box-shaped member to the corresponding lower structure or upper structure. A sixth step involves placing a rubber shoe between the two box-shaped members, or between the box-shaped member and the plate-shaped member, and fixing the rubber shoe to the upper and lower box-shaped members or the plate-shaped member. A bridge bearing replacement method comprising a seventh step of retracting the jack and supporting the superstructure on the rubber shoe.

2. The bridge bearing replacement method according to claim 1, wherein the third step is performed at a location other than the installation location of the box-shaped member.

3. The bridge bearing replacement method according to claim 1 or 2, wherein the fourth and fifth steps involve fixing the box-shaped member, which is positioned to cover the remaining existing bearing member, with a plurality of newly installed anchors provided on the corresponding substructure or superstructure and the filling material.

4. The bridge bearing replacement method according to claim 3, wherein the fourth step is to provide a plurality of the newly installed anchors to the corresponding substructure or superstructure, and then to form fixing through holes in the bottom plate according to the positions of the newly installed anchors.

5. The bridge bearing replacement method according to claim 1 or 2, wherein the fourth step involves fixing the plate-shaped member to the corresponding substructure using a plurality of existing anchors that had fixed the removed existing bearing member.

6. The fourth step is to fix the plate-shaped member with a plurality of newly installed anchors provided on the corresponding substructure or superstructure, the bridge bearing replacement method according to claim 5.

7. The bridge bearing replacement method according to claim 6, wherein the fourth step is to provide a plurality of the newly installed anchors to the corresponding substructure or superstructure, and then to form fixing through holes in the plate-shaped member according to the position of the newly installed anchors.

8. A bridge bearing structure, A lower support structure fixed to the bridge's substructure, An upper support structure fixed to the superstructure of the bridge and supported by the lower support structure, The system comprises a rubber shoe interposed between the lower support structure and the upper support structure and fixed to the lower support structure and the upper support structure, At least one of the lower support structure and the upper support structure is An existing support member fixed to the corresponding substructure or upper structure by a plurality of existing anchors, A box-shaped member comprising a bottom plate positioned opposite the existing support member, side plates provided on the outer circumference of the bottom plate, and a plurality of rib plates welded to the side plate and the bottom plate, and positioned to cover the existing support member, A bridge bearing structure comprising a filling material filled inside the box-shaped member.

9. The bridge bearing structure according to claim 8, wherein at least one of the lower bearing structure and the upper bearing structure further comprises a plurality of newly installed anchors for fixing the box-shaped member to the corresponding substructure or superstructure.

10. The bridge bearing structure according to claim 9, wherein a plurality of the newly installed anchors are arranged on the outer periphery of the bottom plate corresponding to the rib plate.

11. The lower support structure or the upper support structure is, A bridge bearing structure according to any one of claims 8 to 10, comprising a plate-shaped member to which the rubber shoe is fixed, which is fixed to the corresponding substructure or superstructure by a plurality of existing anchors.

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