Mounting structure and installation method for mounting components

Abstract

The present invention aims to provide a mounting structure and a method for installing mounting members that can withstand large horizontal forces and shorten the construction period. [Solution] The mounting structure L according to the present invention is a mounting structure L for attaching a support member that supports the superstructure to the substructure of a bridge to a main girder 21, comprising: a main girder 21 having grooves 21s extending in the vertical direction formed on both sides of the lower side at predetermined intervals in the left-right direction; a mounting member 50 positioned at a distance from and opposite to both sides and the bottom surface of the main girder 21 where the grooves 21s are formed; and a filler material F cast between the main girder 21 and the mounting member 50, wherein the mounting member 50 has a through hole 52h formed at a location opposite to the grooves 21s, a bolt V is inserted into the through hole 52h, and the tip of the bolt V is positioned to be embedded in the filler material F in the grooves 21s.

Description

Technical Field

[0001] The present invention relates to an attachment structure for attaching a bearing to the main girder of a bridge and a construction method of an attachment member.

Background Art

[0002] A bearing of a bridge is installed between an upper structure such as a main girder and a lower structure such as a bridge abutment or pier. The bearing is an important member that exhibits functions such as absorbing displacement (expansion / contraction, rotation, etc.) of the upper structure with respect to the lower structure and transmitting a load to the lower structure. Due to aging caused by long-term use, various functions of this bearing may deteriorate or disappear. In addition, due to the strengthening of seismic standards, there are cases where replacement with a seismic-resistant bearing is required. In such cases, replacement of the bearing is necessary, and various techniques have been proposed so far regarding the technique for replacing the bearing.

[0003] For example, Patent Document 1 proposes a replacement method for a bearing device of a bridge girder shown below. Hole-drilling is performed horizontally on the pier under the bearing device, a temporary support jack for the hole is installed in the drilled hole, the bridge girder is temporarily supported using the temporary support jack, then the temporary support jack for the hole installed in the drilled hole is removed, and the concrete body above the drilled hole and the old bearing device are removed. Then, a new bearing device is installed in the removed concrete body part, filled with a curing material to fix the bearing device and the upper part of the pier, and then the temporary support jack is removed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the construction of conventional bearing replacement methods (bearing replacement methods), including those described in Patent Document 1, the applicant of this application has proposed the use of mounting members (so-called "bearing mounting members") for attaching bearings to the main girders. Specifically, after removing the existing supports, parts of the lower sides of the main girder are chipped away, and numerous bolt holes (non-penetrating recesses) are formed. Then, mounting members are positioned to surround the main girder from below, where the bolt holes have been formed. The mounting members are then fixed with bolts so that the through holes in the mounting members connect to the aforementioned bolt holes, and the gap between the main girder and the mounting members is filled with a filler material, thereby integrating the main girder and the mounting members. New supports can be installed as appropriate between the mounting members and the substructure. Furthermore, this mounting component can be used not only when installing the support, but also when attaching the bridge fall prevention mechanism, which supports the superstructure to the substructure, to the main girder.

[0006] By using mounting components, the labor required for replacing bearings, bridge collapse prevention mechanisms, and other components (hereinafter referred to as "support members") can be reduced, and the amount of chipping required can be minimized, thus reducing the impact on the main girders. However, stress tends to concentrate in the bolt holes and bolts formed in the main girders, and there is room for improvement in terms of being able to withstand large horizontal forces. In addition, it is necessary to form numerous bolt holes on both sides of the main girders, and since this work is time-consuming, it is necessary to consider shortening the construction period.

[0007] From this perspective, the present invention aims to provide a mounting structure and a method for installing mounting members that can withstand large horizontal forces and shorten the construction period. [Means for solving the problem]

[0008] The aforementioned problem can be solved by the following means. The mounting structure according to the present invention is a mounting structure for attaching a support member that supports the superstructure to the substructure of a bridge to a main girder, comprising: a main girder having grooves extending in the vertical direction formed on both lower sides at predetermined intervals in the left-right direction; a mounting member positioned at a distance from and opposite to both sides and the bottom surface of the main girder where the grooves are formed; and a filler material cast between the main girder and the mounting member, wherein the mounting member has a through hole formed in a location opposite to the groove, a bolt is inserted into the through hole, and the tip of the bolt is positioned to be embedded in the filler material in the groove. According to the mounting structure of the present invention, grooves extending vertically are formed on both sides of the main girder, and the tips of the bolts inserted through the through holes of the mounting member are positioned to be embedded in the filler material within the grooves. As a result, the main girder and the mounting member are properly fixed via the filler material within the grooves. Furthermore, unlike conventional configurations that fix the two members (main girder and mounting member) via numerous bolts, the two members are fixed via the filler material (bolt-reinforced filler material) within the vertically extending grooves, thus avoiding situations where stress concentrates and enabling resistance to large horizontal forces. In addition, with the mounting structure of the present invention, it is only necessary to form grooves on both sides of the main girder, eliminating the need to form numerous bolt holes in the main girder as in conventional methods, thus shortening the construction period. Furthermore, the mounting structure according to the present invention preferably comprises a base plate facing the lower bottom surface of the main girder, two face plates facing both lower sides of the main girder, and two connecting members connecting the base plate and the two face plates, respectively. According to the mounting structure of the present invention, since the face plate and base plate, which are mounting members, are securely connected by a connecting member, it can withstand large upward forces. Furthermore, in the mounting structure according to the present invention, it is preferable that the through-holes are formed at different positions in the vertical direction at locations facing the grooves. According to the mounting structure of the present invention, the formation of multiple through holes allows multiple bolts inserted into the multiple through holes to more firmly reinforce the filler material in the groove. The method for constructing an attachment member according to the present invention is a method for constructing an attachment member for attaching a support member that supports the superstructure to the main girder of a bridge to the substructure, and includes a groove forming step of forming grooves extending vertically on both sides of the lower side of the main girder at predetermined intervals in the left-right direction, an attachment member installation step of installing the attachment member at positions separated from and facing both sides and the bottom surface of the main girder where the grooves are formed, a bolt insertion step of inserting bolts into through holes formed in the attachment member, and a casting step of filling and hardening a filler while the main girder and the attachment member are separated, wherein the through holes of the attachment member are formed at locations facing the grooves when the attachment member is installed on the main girder, and in the bolt insertion step, the tip of the bolt inserted into the through hole is positioned within the groove. According to the installation method for the mounting member of the present invention, grooves extending vertically are formed on both sides of the main girder, and the tips of bolts inserted through the through-holes of the mounting member are positioned within the grooves. As a result, the main girder and the mounting member are properly fixed together via the filler material in the grooves. Furthermore, unlike conventional configurations where the two members (main girder and mounting member) are fixed together via the filler material (bolt-reinforced filler material) in the vertically extending grooves, the two members (main girder and mounting member) are fixed together via the filler material (bolt-reinforced filler material) in the grooves. This avoids situations where stress concentrates and allows the system to withstand large horizontal forces. In addition, according to the installation method for the mounting member of the present invention, it is only necessary to form grooves on both sides of the main girder. Therefore, it is not necessary to form a large number of bolt holes in the main girder as in conventional systems, thus shortening the construction period. [Effects of the Invention]

[0009] According to the mounting structure and mounting member installation method of the present invention, it is possible to withstand large horizontal forces and shorten the construction period. [Brief explanation of the drawing]

[0010] [Figure 1] It is an overall schematic diagram of the structure of the bridge. [Figure 2A] It is a sectional view taken along the A-A arrow in FIG. 1. [Figure 2B] It is a sectional view taken along the B-B arrow in FIG. 1. [Figure 3A] It is an enlarged sectional view of part a in FIG. 2A as seen from the bridge axis direction. [Figure 3B] It is an enlarged sectional view of part b in FIG. 2B as seen from the bridge axis direction. [Figure 4A] It is an enlarged sectional view of part a in FIG. 2A as seen from the direction perpendicular to the bridge axis. [Figure 4B] It is an enlarged sectional view of part b in FIG. 2B as seen from the direction perpendicular to the bridge axis. [Figure 5] It is an exploded perspective view of the mounting structure. [Figure 6] It is a perspective view of the main girder with concave grooves formed on both lower side surfaces. [Figure 7] It is a perspective view of the mounting member. [Figure 8] It is a perspective view of the mounting structure with the mounting member installed on the main girder. [Figure 9] It is a sectional view of the mounting structure with the mounting member installed on the main girder and a filling material placed between the two members. [Figure 10] It is a flowchart of the construction method of the mounting member.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments for carrying out the mounting structure and the construction method of the mounting member according to the present invention will be described with reference to the drawings.

[0012] [Structure of the Bridge (Overview)] First, the structure of the bridge to which the mounting structure according to the present embodiment is applied will be described with reference to FIG. 1. As shown in Figure 1, the bridge 100 comprises a superstructure 20 such as a main girder 21, a substructure 30 such as abutments 31 and piers 32, bearings 41 installed between the superstructure 20 and the substructure 30, and a bridge collapse prevention mechanism 42 that supports the main girder 21 relative to the substructure 30. The bridge 100 also includes mounting members 50 for attaching support members 40 such as the bearings 41 and the bridge collapse prevention mechanism 42 to the main girder 20. As shown in Figures 2A and 2B, the main girders 21 are so-called T-girders, and three of them are installed in a row perpendicular to the bridge axis. Also, as shown in Figures 3A and 4A, mounting members 50 are attached to the underside of the main girders 21 via filler material F and bolts V, and these mounting members 50 fix the main girders 21 to the support members 41. Similarly, as shown in Figures 3B and 4B, mounting members 50 are attached to the underside of the main girders 21 via filler material F and bolts V, and these mounting members 50 fix the main girders 21 to the fall prevention mechanism 42 (support members 40). Although the general structure of the bridge 100 has been described, it is not particularly limited as long as it is a known bridge structure, and for example, the number and shape of each member may be changed as appropriate. Also, the method of fixing the mounting member 50, the support member 40 (bearing 41, fall prevention mechanism 42), and the substructure 30 is not particularly limited, and for example, the contact surfaces between each member may be fixed with bolts or the like. Furthermore, the bearing 41 and fall prevention mechanism 42 are not particularly limited as long as they are known devices. The mounting structure according to this embodiment will be described in detail below.

[0013] [Mounting structure] The mounting structure L according to this embodiment is a structure (framework) for attaching support members 40, such as bearings 41 and bridge fall prevention mechanisms 42, to the main girder 21. As shown in Figure 5, the mounting structure L comprises a main girder 21, a mounting member 50, and a filler material F cast between the main girder 21 and the mounting member 50.

[0014] (main digit) The main girder 21 is a girder that supports the load of the entire superstructure, and is a type of superstructure 20. As shown in Figure 6, the main girder 21 has grooves 21s extending in the vertical direction formed on both lower sides at predetermined intervals in the horizontal direction. As shown in Figure 8, the groove 21s is formed from the bottom surface of the main girder 21 up to the height of the face plate 52, but it is not particularly limited as long as it is greater than or equal to the height of the bolt hole 52h formed in the face plate 52. Furthermore, as shown in Figure 9, the grooves 21s are formed opposite the through holes 52h of the face plate 52, and the same number of grooves as the through holes 52f in the left-right direction, i.e., six grooves are formed on each side. Note that the width (length in the left-right direction) of the grooves 21s should be greater than the width of the bolt V.

[0015] (Mounting components) The mounting member 50 is a member used to attach support members 40, such as the bearing 41 and the bridge fall prevention mechanism 42, to the main girder 21. As shown in Figure 7, the mounting member 50 comprises one base plate 51, two face plates 52, and two connecting members 53. Then, as shown in Figure 8, the mounting member 50 is positioned at a distance from and opposite to both sides and the bottom surface of the main girder 21 in which the groove 21s are formed.

[0016] As shown in Figure 5, the base plate 51 has a roughly square plate shape. The base plate 51 has four recesses 51r formed at both the front and rear ends of its upper surface. The faceplate 52 comprises a main plate that is rectangular in shape, and two sub-plates that extend vertically from both ends (the left end and the right end) in the longitudinal direction of the main plate. The faceplate 52 has four protrusions 52c formed on its lower end. By inserting the protrusion 52c of the faceplate 52 into the recess 51r of the base plate 51, the faceplate 52 is fixed perpendicularly to the upper surface of the base plate 51.

[0017] As shown in Figure 7, the connecting member 53 is a so-called L-shaped bracket. With the base plate 51 and the face plate 52 fixed vertically, the two members are connected at the corner (inner corner) with the connecting member 53. Furthermore, by connecting the two members with this connecting member 53, welding or other joining methods become unnecessary, making it possible to withstand large upward forces.

[0018] (filling material) The filler material F is a material that is filled into the gap between the main girder 21 and the mounting member 50. As shown in Figure 5, the filler material F is formed when the filler material is filled and hardened in the space between the bottom surface of the main girder 21 and the base plate 51, and between both sides of the main girder 21 and the two face plates 52. On the inside of the filler material F, a linear protrusion Fc extending in the vertical direction is formed by the filler material filled in the groove 21s of the main girder 21. The filler F can be any conventionally known concrete composition or mortar composition, such as J-THIFCOM (registered trademark).

[0019] (Positional relationship between grooves and bolts, etc.) As shown in Figure 9, through holes 52h are formed in the two face plates 52 at positions opposite to the grooves 21s formed on both sides of the main girder 21. Bolts V are inserted into these through holes 52h from the left and right outer sides, and a filler material F is poured between the two face plates 52 and the main girder 21. The tip of the bolt V is located inside the groove 21s. In other words, the length Lv of the shaft portion of the bolt V inserted into the faceplate 52 is shorter than the length L1 from the outer surface of the faceplate 52 to the bottom surface of the groove 21s of the main girder 21, and longer than the length L2 from the outer surface of the faceplate 52 to the side surface of the main girder 21. As the groove 21s and bolts V are in the positional relationship described above, the filler material F cast inside the groove 21s is reinforced by the bolts V. As a result, as shown in Figure 5, the linear protrusions Fc that extend in the vertical direction and are formed inside the filler material F are very firmly connected to the groove 21s of the main girder 21, and can withstand large horizontal forces. Furthermore, as shown in Figure 8, the formation of two through-holes 52h at different positions in the vertical direction of the faceplate 52 allows bolts V inserted into these through-holes 52 to more firmly reinforce the filler material F.

[0020] As described above, in the mounting structure L according to this embodiment, grooves 21s extending vertically are formed on both sides of the main girder 21, and the tips of the bolts V inserted through the through holes 52h of the mounting member 50 are positioned to be embedded in the filler material F in the grooves 21s. Thus, the main girder 21 and the mounting member 50 are properly fixed via the filler material F in the grooves 21s. Furthermore, unlike conventional configurations (configurations that fix via a large number of bolts), since both members (main girder 21 and mounting member 50) are fixed via the filler material F (filler material F reinforced by bolts V) in the grooves 21s extending vertically, situations in which stress concentrates can be avoided, and the structure can withstand large horizontal forces. In addition, the mounting structure L according to this embodiment only requires the formation of grooves 21s on both sides of the main girder 21, which can shorten the construction period compared to conventional structures (structures that form a large number of bolt holes in the main girder).

[0021] [Installation method for mounting components] The installation method for the mounting member according to this embodiment includes a groove formation step S1, a mounting member installation step S2, a bolt insertion step S3, and a casting step S4, as shown in Figure 10. Furthermore, when replacing support members such as bearings or bridge collapse prevention mechanisms, the process includes a removal step of removing the existing support members and a new installation step of installing the new support members. The following describes each step in detail, referring to diagrams as appropriate.

[0022] (Removal process) In the removal process, existing support members that need to be replaced are removed. The method for removing support members during the removal process can be carried out using conventionally known methods. For example, the superstructure can be jacked up, the existing support members can be released from their connections to other members, and then the support members can be removed.

[0023] (Groove formation process) In the groove formation process S1, as shown in Figure 6, grooves 21s extending in the vertical direction are formed on both lower sides of the main girder 21 at predetermined intervals in the left-right direction. Then, in the groove formation process S1, the desired groove 21a should be formed considering the configuration of the mounting member 50 prepared in advance (such as the position of the through hole 52h). In addition, during the groove formation process S1, chipping can be performed on both sides of the main girder 21 as appropriate so that the mounting member 50 can be properly installed on the main girder 21.

[0024] (Installation process for mounting components) In the mounting member installation process S2, after the groove formation process S1, the mounting member 50 is installed at positions that are spaced apart from and opposite to both sides and the bottom surface of the main girder 21 in which the groove 21a has been formed. Then, in the mounting member installation step S2, as shown in Figure 8, the mounting member 50 is installed so that the groove 21a formed in the groove forming step S1 and the through hole 52h of the mounting member 50 face each other. In the mounting member installation process S2, the base plate 51 and the two face plates 52 may be installed on the main girder 21 in a connected state as shown in Figure 7. Alternatively, the base plate 51 may be installed on the main girder 21 first, and then the two face plates 52 may be connected to the base plate 51. Alternatively, the base plate 51 with one face plate 52 attached may be installed on the main girder 21 first, and then the remaining face plate 52 may be connected to the base plate 51.

[0025] (Bolt insertion process) In the bolt insertion process S3, after the mounting member installation process S2, the bolt V is inserted into the through hole 52h formed in the mounting member 50. Then, in the bolt insertion process S3, as shown in Figure 9, the bolt V is inserted so that its tip is located inside the groove 21s of the main girder 21.

[0026] (Concrete pouring process) In the concrete casting process S4, after the bolt insertion process S3, the filler material F is filled and hardened while the main girder 21 and the mounting member 50 are separated. The concrete placement method in the concrete placement process S4 can be carried out using conventionally known methods, and in order to properly harden the filler material F used, watering of the filling area and setting of curing conditions should be performed as appropriate. As shown in Figure 8, when filling with the filler material F in the concrete placement process S4, it is preferable to install formwork (not shown) on the left and right sides to fill the gaps between the main girder 21 and the mounting member 50 so that the filler material F does not flow out of the gaps. Furthermore, it is preferable to use ultra-high-strength concrete such as J-Tifcom (registered trademark) as the filler material used in the concrete placement process S4.

[0027] (New installation process) In the new construction process, a new support member 40 is installed. The method for installing the new support member 40 in the new construction process can be carried out using a conventionally known method. For example, after placing the support member 40 between the substructure 30 and the mounting member 50, the contact surfaces between the support member 40 and the substructure 30, and the contact surfaces between the support member 40 and the mounting member 50 can be fixed with bolts or the like. This new installation process may be carried out before or after the mounting member installation process S2, or simultaneously with the mounting member installation process S2.

[0028] As described above, the installation method for the mounting member 50 according to this embodiment involves forming grooves 21s extending vertically on both sides of the main girder 21, and the tips of the bolts V inserted through the through holes 52h of the mounting member 50 are located within the grooves 21s. As a result, the main girder 21 and the mounting member 50 are properly fixed via the filler material F within the grooves 21s. Unlike conventional configurations (which use multiple bolts for fixing), both members (main girder 21 and mounting member 50) are fixed via the filler material F (reinforced by the bolts V) within the vertically extending grooves 21s. This avoids situations where stress concentrates and allows the system to withstand large horizontal forces. In addition, the installation method for the mounting member 50 according to the present invention only requires forming grooves 21s on both sides of the main girder 21, which can shorten the construction period compared to the conventional structure (a structure in which a large number of bolt holes are formed in the main girder).

[0029] [Differentiation] Next, we will explain some modified examples, referring to the diagrams as appropriate. In Figure 5, six grooves 21s are formed on each side of the main girder 21, but the number is not particularly limited and can be more or fewer. However, from the perspective of responding to greater horizontal forces, it is preferable to have a larger number of grooves 21s, such as 6 to 10 per side of the main girder. In Figure 5, the through holes 52h of the faceplate 52 are formed in pairs vertically at each position opposite the groove 21s, but the number is not particularly limited and may be more or less. However, from the viewpoint of further reinforcing the linear protrusions Fc of the filler material F with bolts V inserted into the through holes 52h, it is preferable to have a larger number of through holes 52h in the vertical direction. [Explanation of Symbols]

[0030] 100 Bridges 20 Superstructure 21 Main girder (superstructure) 21s concave groove 30 Undercarriage 31. Abutment (substructure) 32 Bridge piers (substructure) 40 Support member 41. Support (support member) 42 Bridge collapse prevention mechanism (support member) 50 Mounting components 51 Base Plate 51r recess 52 Faceplates 52h through hole 52c protrusion 53 Connecting member L Mounting structure V-bolt F Filling material Fc linear protrusion S1 Groove formation process S2 Installation process for mounting components S3 Bolt insertion process S4 Casting Process

Claims

1. A mounting structure for attaching support members that support the superstructure to the main girder of a bridge, A main girder having grooves extending vertically formed on both sides of its lower surface at predetermined intervals in the left-right direction, Mounting members are positioned at a distance from and opposite to both sides and the bottom surface of the main girder in which the groove is formed, The system comprises a filler material cast between the main girder and the mounting member, The mounting member has a through hole formed in a location opposite to the groove, A mounting structure characterized in that a bolt is inserted into the through hole, and the tip of the bolt is positioned so as to be embedded in the filler material in the groove.

2. The mounting structure according to claim 1, characterized in that the mounting member comprises a base plate facing the lower bottom surface of the main girder, two face plates facing each of the two lower sides of the main girder, and two connecting members connecting the base plate and the two face plates, respectively.

3. The mounting structure according to claim 1 or 2, characterized in that the through holes are formed in multiple locations at different positions in the vertical direction opposite to the groove.

4. A method for installing mounting members for attaching support members that support the superstructure to the main girder of a bridge, wherein A groove forming step is performed on both sides of the lower side of the main girder, in which grooves extending vertically are formed at predetermined intervals in the left-right direction, A mounting member installation step involves installing mounting members at positions that are spaced apart and facing each other on both sides and the bottom surface of the main girder in which the grooves are formed, A bolt insertion step involves inserting a bolt into a through hole formed in the mounting member, The process includes a casting step of filling and hardening a filler material while the main girder and the mounting member are separated, The through-hole of the mounting member is formed in a location that faces the groove when the mounting member is installed on the main girder. A method for installing a mounting member, characterized in that, in the bolt insertion step, the tip of the bolt inserted into the through hole is located within the groove.

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