JP2011069191A - Construction method for moving support part in bridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a support part movable without replacing an existing support to a new support, so as to prevent the support from destruction in a large earthquake and to reduce a burden in the lower structure. <P>SOLUTION: In a construction method for moving the support part, the existing support 1 is arranged between an upper structure 2 and a lower structure 4, and a sliding plate 19 which generates sliding between the upper structure 2 and thereof, is arranged on the upper face of the existing support 1. Practically, an upper-structure-side sliding plate 17 is arranged on the lower face of the upper structure after jacking up the upper structure 2 and cutting/moving a sole plate and a boss, and the support-side sliding plate 19 is arranged on the upper face of the existing support to jack down the upper structure 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for mobilizing a support portion in a bridge, and more particularly to a technique for moving a support portion without removing or remodeling an existing support to prevent destruction of bridge components during an earthquake.

  Existing bearings installed under the old seismic design standards are designed to be fixed until the Level 1 earthquake with respect to their fixing direction (for example, omnidirectional for fixed bearings and perpendicular to the bridge axis for movable bearings) Destroyed during a Level 2 earthquake. However, its fracture strength is not clear, and the form of damage such as hindering the vertical load support function of the bearing is unclear. Level 1 and 2 ground motions are ground motions stipulated in “Road Bridge Specification / Explanation V Seismic Design Bias” (Japan Road Association).

  In addition, with regard to the movable direction of the existing bearing (for example, the direction of the bridge axis in the case of the movable bearing), a movement limiting device designed with a level 1 proof strength to limit excessive movement is incorporated in the bearing body. It will be destroyed during an earthquake. However, in this case as well, the fracture resistance is not clear, and the form of damage such as breakage of not only the movement limiting device but also the upper eyelid is unclear.

  In this way, the existing bearings are not clearly destructive, so the impact on the lower structure becomes unclear during a level 2 earthquake, and an unexpected earthquake inertia force acts on the lower structure. Further, when the bearing body is reinforced so as not to break during a level 2 earthquake and the proof stress is increased, the burden of the inertial force during the earthquake of the lower structure increases.

  Based on the background described above, in order to cope with Level 2 ground motion, a method of replacing existing bearings with new seismic isolation bearings has been adopted. However, the new bearing is expensive and therefore has a disadvantage that it is inferior in economic efficiency. In addition, replacement of existing bearings is problematic in terms of workability and construction cost. In other words, when replacing existing bearings, the conventional technology requires turning the lower structural concrete on the lower surface of the bearing, removing the existing bearings, installing pedestal concrete, installing anchor bolts, and installing new bearings. In addition, the construction cost is increased due to poor workability.

  In addition, the bearing height of the existing bearing is as low as about 30 cm, and the work in a very narrow place is inferior in workability for grinding the concrete of the lower structure. When installing the anchor bolt, it is necessary to install the anchor bolt at a position where there is no existing reinforcing bar after exploring with electromagnetic wave radar etc. in advance so as not to cut the existing reinforcing bar embedded in the lower structure concrete . In addition, the pin bearing may have a very large reaction force and may not be replaced.

  Patent Document 1 states that, without removing an existing bearing, the existing bearing is modified to be a sliding bearing, and a seismic isolation device is disposed between the lower surface of the existing bridge girder and the upper surface of the existing pier or the side surface of the existing pier. Claim 1) A seismic isolation method for a bridge is disclosed. However, in this prior art, referring to the detailed description of the invention, although the anchor bar is left without being removed, the upper and lower rods are newly installed (paragraphs 0014, 0015 and FIG. 2). a)), it must be said that it has been substantially replaced with a new bearing. Moreover, this new bearing is a sliding bearing in which the bearing itself has a sliding function.

JP-A-9-41321

The present invention has been made based on the technical background as described above, and achieves the following object.
The object of the present invention is to make the support part movable without replacing the existing support with a new support, thereby preventing damage to the support in the event of a large earthquake, reducing the burden on the substructure, and construction. It is an object of the present invention to provide a method for mobilizing a support portion in a bridge that is extremely simple and can be kept at a low construction cost.

The present invention employs the following means in order to achieve the above object.
That is, the present invention is a mobilization method of a support part in which an existing support is installed between the upper structure and the lower structure,
The method of mobilizing a support portion in a bridge is characterized in that a slip plate is provided on the upper surface of the existing support to generate a slip between the upper structure.

More specifically, according to the present invention, a boss provided on an upper surface of an existing support is fitted in a boss hole provided on the sole plate between an upper structure and a lower structure provided with a sole plate on a lower surface. It is a mobilization method of the support part installed in the combined state,
After jacking up the upper structure and cutting and removing the sole plate and the boss,
An upper structure side sliding plate is installed on the lower surface of the upper structure, and a bearing side sliding plate that causes a slip between the upper structure side sliding plate is installed on the upper surface of the existing bearing,
The upper structure is jacked down.

Further, according to the present invention, the boss provided on the upper surface of the existing support is fitted in the boss hole provided on the sole plate between the upper structure and the lower structure provided with the sole plate on the lower surface. It is a mobilization method of the installed bearing part,
After crushing the lower structural concrete around the existing bearing, jacking down the existing bearing, cutting and removing the sole plate and the boss,
An upper structure side sliding plate is installed on the lower surface of the upper structure, and a bearing side sliding plate that causes a slip between the upper structure side sliding plate is installed on the upper surface of the existing bearing,
The existing support is jacked up, and a mortar is filled in the turned portion of the lower structural concrete.

  When the boss is cut and removed, a part of the boss may be left, and the remaining boss may be fitted into a hole provided in the bearing-side slide plate. Further, a knock-off type set bolt that penetrates the upper structure side sliding plate and the bearing side sliding plate between both the upper structure and the existing bearing and has a cut fracture surface on both sliding surfaces may be provided. Good. You may make it install these slide plates by adjusting the friction coefficient between the said upper structure side slide plate and the said support side slide plate.

  According to this construction method, the upper structure is not moved by the moving function of the support body, but the upper structure is moved with respect to the existing support. Therefore, the existing support is not required to be replaced with an expensive new support. It is possible to prevent damage to the bearing during an earthquake and to reduce the burden on the substructure. In addition, it is possible to minimize or minimize the work of turning the substructure concrete, and it is also unnecessary to install anchor bolts, so that the construction is extremely simple and the construction cost can be kept low.

It is a construction procedure figure which shows embodiment of this invention. It is a figure which shows the construction procedure following FIG. It is a figure which shows the construction procedure following FIG. It is sectional drawing which shows the attachment state of a knock-off type | mold bolt. It is a construction procedure figure which shows another embodiment. It is a construction procedure figure following FIG. FIG. 7 is a construction procedure diagram subsequent to FIG. 6. FIG. 8 is a construction procedure diagram subsequent to FIG. 7.

  Embodiments of the present invention will be described below with reference to the drawings. The embodiment shown in FIG. 1 to FIG. 3 is an example in which a bearing portion in which a pin bearing, which is one of fixed bearings, is installed as an existing bearing is moved. The serial numbers (1) to (6) attached to each figure show the construction procedure, and (a) and (b) in each construction procedure figure are the cross-sectional view in the direction of the bridge axis and the arrow in the direction perpendicular to the bridge axis, respectively. Is shown.

  First, the outline of the pin support will be described with reference to FIG. 1 (1) showing the installation state of the existing pin support. The pin support 1 includes an upper rod 3 fixed to the lower surface of the upper structure 2 that is a bridge girder, and a lower rod 5 fixed to the upper surface of the lower structure 4 that is a bridge pier or an abutment. Semi-cylindrical boss portions 6 and 7 are formed on the lower surface of the upper collar 3 and the upper surface of the lower collar 5. These boss portions 6 and 7 face each other to form a substantially cylindrical boss portion, and a pin 8 is fitted into the boss portion. As a result, the upper rod 3 can rotate in the vertical direction with respect to the lower rod 5.

  Semi-annular protrusions 9 and 10 are provided at the inner peripheral centers of the semi-cylindrical boss portions 6 and 7, respectively. On the other hand, the pin 8 is provided with an annular groove portion into which the semi-annular protrusions 9 and 10 are fitted. As a result, the upper rod 3 cannot move in the direction perpendicular to the bridge axis with respect to the lower rod 5.

  A boss 11 is provided on the upper surface of the upper collar 3. In the figure, a steel girder is shown as the upper structure 2, and a sole plate 13 is fixed to the lower surface of the flange 12 by welding. A boss hole 14 is provided in the sole plate 13. The upper collar 3 is fixed to the upper structure 2 by a set bolt 15 attached to the flange 12 with the boss 11 fitted in the boss hole 14.

  A base plate 16 is fixed to the lower structure 4 by anchor bolts (not shown), and a lower collar 5 is fixed to the upper surface of the base plate 16. As the lower structure 4, an abutment is shown in the illustrated example.

  In order to move the support portion on which the pin support 1 is installed as described above, first, as shown in FIG. 1 (2), the set bolt 15 is removed and the upper structure 2 is jacked up. The jack-up amount is a slight amount (about 20 mm) that can be cut by a wire saw, which will be described later, and has little influence on other equipment of the bridge, for example, the drainage device of the existing extension device.

  Next, as shown in FIG. 2 (3), the boss 11 is removed by cutting with a cutting machine such as a wire saw. At this time, a part of the boss 11 is left. Further, the sole plate 13 is also removed by cutting the welded portion by a cutting machine such as a grinder cutting machine or gas gowning. A portion indicated by a chain line in the figure is a cut and removal portion.

  Next, as shown in FIG. 2 (4), the upper structure side slide plate 17 is attached to the lower surface of the flange 12 of the upper structure 2. As the upper structure side slide plate 17, for example, a stainless steel (SUS) plate is used. The upper structure side slide plate 17 is attached by mounting bolts 18 having holes formed in the flange 12 and inserted therein. The flange 12 of the upper structure 2 is inclined along the bridge axis direction on the abutment so that the mounting surface of the upper structure side slide plate 17 attached to the flange 12 is also inclined along the same direction. Is taper processed.

  Next, as shown in FIG. 3 (5), the bearing side slide plate 19 is installed on the upper surface of the upper collar 3. The bearing side sliding plate 19 is formed by forming a recess on the surface of a main body plate made of steel, and fitting the sliding member 22 (see FIG. 4) into the recess. As the sliding material 22, for example, a tetrafluoroethylene (PTFE) plate is used. The bearing-side slide plate 19 has an outer dimension that is substantially the same as the outer dimension of the upper surface of the upper collar 3, and is provided with a hole 20 in the center where the remaining portion 11a of the boss 11 is fitted. The bearing side slide plate 19 is simply placed on the upper surface of the upper collar 3 with the remaining portion 11 a fitted in the hole 20. Thus, by leaving a part of the boss 11 as the remaining portion 11a, the bearing-side slide plate 19 can be positioned using the remaining portion 11a, and the installation thereof becomes easy.

  Next, as shown in FIG. 3 (6), the upper structure 2 is jacked down. In this state, the upper structure 2 slips with respect to the existing support 1, specifically, with respect to the upper collar 3 in all horizontal directions. That is, the support part is always movable during both the level 1 earthquake and the level 2 earthquake.

  This invention construction method is applicable not only to the bearing part in which the above-mentioned pin bearing is installed, but also to various bearing parts in which the fixing direction is set by the existing bearing. Specifically, steel bearings such as bearings with rubber bearings installed as existing bearings, line contact bearings as existing bearings, pin bearings described above, pin roller bearings, bearing plate bearings, spherical bearings, cylindrical surface bearings, point contact bearings, etc. It can be applied to a bearing part in which a manufactured bearing is installed.

  The support part mobilized by the method of the present invention is not moved by the moving function of the support body, but the upper structure moves relative to the existing support, so it does not depend on the movement limit distance of the existing support and moves. You can set the amount. Furthermore, it is possible to cope with a large amount of movement. In the above embodiment, the upper structure side sliding plate 17 is provided on the flange 12 of the upper structure 2. However, the flange 12 and the bearing side sliding plate 19 are removed by cutting and removing the sole plate 13 without installing the upper structure side sliding plate 17. It is also possible to cause a slip between the two.

The friction coefficient between the two can be adjusted by appropriately selecting the combination of materials of the upper structure side sliding plate 17 and the bearing side sliding plate 19 as follows.
(1) When high friction (coefficient of friction: 0.2 to 0.5) is expected to reduce friction during an earthquake ・ Combination of sintered metal-based sliding material and stainless steel ・ Combination of steel and steel ・ Combination of iron and galvanization
(2) When friction reduction during an earthquake is expected with medium friction (friction coefficient: 0.1 to 0.15) ・ Combination of PTFE and stainless steel ・ Combination of PTFE and steel
(3) When using low friction (friction coefficient: 0.02 to 0.08) to cut off the seismic force without expecting frictional damping during an earthquake ・ Combination of fiber reinforced thermosetting resin and stainless steel ・ Combination of polyamide and stainless steel

  The movable support portion can take various forms by being combined with other members. For example, in the case of the above-described bearing portion having the existing pin bearing 1, as shown in FIG. 3 (6), the upper structure 2 and the existing bearing 1 are fixed by using a knock-off type set bolt 21. Can be fixed up to level 1 ground motion and movable during level 2 earthquakes.

  As shown in FIG. 4, the knock-off type set bolt 21 is a bolt that is provided with a constricted portion 25 having a reduced outer diameter on its shaft portion 21 a so as to be sheared by a horizontal load. Shows the surface. The surface in contact with the upper structure side sliding plate 17 and the bearing side sliding plate 19, specifically the sliding material 22, is a sliding surface 23 during an earthquake, and the knock-off type set bolt 21 has a shear fracture surface 24 with a sliding surface 23 during an earthquake. It is attached so that it is located nearby.

  In the bearing portion using the knock-off type bolt 21 as described above, since the upper structure 2 and the existing support 1 are fixed by the knock-off type bolt 21 until the level 1 earthquake, the upper structure 2 is fixed to the existing support 1. The upper structure 2 does not move horizontally with respect to the lower structure 4. However, when a level 2 earthquake motion occurs, the knock-off bolt 21 breaks along the shear fracture surface 24 and the superstructure 2 slips against the existing support 1. As a result, the existing bearing 1 will not be destroyed even during a level 2 earthquake, and an excessive load will not be applied to the lower structure 4.

  In addition, as another form of bearing part, vertical load uses existing bearings, and horizontal load is shared by seismic control device, seismic isolation device, reaction force dispersion device, etc. Type B (“Road Bridge Specification / Description” It is possible to adopt a function-separated bearing structure of “V seismic design bias” (Japan Road Association).

  5 to 8 show another embodiment. This embodiment is also an example in which a bearing portion in which a pin bearing which is one of fixed bearings is installed as an existing bearing is movable. As in the above embodiment, the serial numbers (1) to (8) attached to each figure indicate the construction procedure, and (a) and (b) in each construction procedure diagram are respectively a cross-sectional view in the direction of the bridge axis and The bridge axis perpendicular direction view is shown.

  FIG. 5 (1) is a view showing an installed state of the existing pin support 1, and the structure of the pin support is the same as that described in the above embodiment. In this embodiment, the upper structure 2 jacks down the existing pin support 1 without jacking up. Therefore, as shown in FIG. 5 (2), the lower structural concrete around the existing pin support 1 is beaten to form the turned portion 30. At this time, the anchor bolt 31 that fixes the lower rod 5 to the lower structure 4 is not removed and is left as it is.

  Next, as shown in FIG. 6 (3), the existing pin support 1 is supported by a jack via a jig (not shown), and the existing pin support 1 is jacked down using the anchor bolt 31 as a guide. As a result, the boss 11 of the upper collar 3 comes out of the boss hole 14, so that the upper collar 3 is removed from the lower collar 5 as shown in FIG. The removed upper iron 3 is carried to a place other than the construction site, and the boss 11 is cut and removed by the same means as in the above embodiment.

  Next, as shown in FIG. 7 (5), the sole plate 13 is cut and removed by the same means as in the above embodiment. Then, as shown in FIG. 7 (6), the upper structure side slide plate 17 is attached to the lower surface of the flange 12 of the upper structure 2 with the mounting bolts 18. Further, as shown in FIG. 8 (7), the bearing side slide plate 19 is set on the removed upper collar 3, the upper collar 3 is attached to the lower collar 5 again, and the existing pin bearing 1 is restored.

  Next, as shown in FIG. 8 (8), the existing pin bearing 1 is jacked up until the upper structure side sliding plate 17 and the bearing side sliding plate 19 come into contact with each other. In this state, the mortar 32 is filled in the turned portion 30 and cured. Similarly to the embodiment described above, the upper structure 2 and the existing support 1 are fixed using the knock-off type set bolt 21.

  As described above, according to the method of the present invention, the upper structure is not moved by the moving function of the support body, but the upper structure is moved with respect to the existing bearing. Therefore, it is necessary to replace the existing bearing with an expensive new bearing. There is no. For this reason, the work of turning the lower structural concrete and the work of installing the anchor bolt can be omitted. Further, since the existing support can be used as a part of the type B function separation type support part structure, the displacement limiting structure can be omitted.

  According to the present invention, the inertial force at the time of the level 2 earthquake can be prevented from being applied or reduced by making the support portion movable in the fixing direction and further adding friction damping as necessary. As a result, it is possible to minimize the damage to the bridge piers and the entire bridges that have moved the support parts. In addition, even if a movement amount during an earthquake exceeding the movement limit distance of the existing bearing occurs in the event of a level 2 earthquake, the existing bearing is not damaged. Furthermore, by combining with various devices, the inertial force at the time of a level 2 earthquake can be reduced as a function-separated type bearing using an existing bearing.

1 Pin support (existing support)
2 Upper structure 3 Upper flange 4 Lower structure 5 Lower flange 8 Pin 11 Boss 11a Boss remainder 12 Flange 14 Boss hole 15 Set bolt 17 Upper structure side sliding plate 19 Lower structure side sliding plate 21 Knock-off type set bolt 22 Sliding material 23 Sliding surface 24 Shear fracture surface

Claims (6)

Between the superstructure and the substructure, it is a mobilization method of the support part where the existing support is installed,
A method for mobilizing a support portion in a bridge, wherein a slip plate is formed on the upper surface of the existing support to generate a slip with the superstructure. Between the upper structure and the lower structure provided with the sole plate on the lower surface, the existing support is installed in a state where the boss provided on the upper surface is fitted in the boss hole provided on the sole plate. The mobilization method of
After jacking up the upper structure and cutting and removing the sole plate and the boss,
An upper structure side sliding plate is installed on the lower surface of the upper structure, and a bearing side sliding plate that causes a slip between the upper structure side sliding plate is installed on the upper surface of the existing bearing,
A method for mobilizing a support portion in a bridge, wherein the upper structure is jacked down. Between the upper structure and the lower structure provided with the sole plate on the lower surface, the existing support is installed in a state where the boss provided on the upper surface is fitted in the boss hole provided on the sole plate. The mobilization method of
After crushing the lower structural concrete around the existing bearing, jacking down the existing bearing, cutting and removing the sole plate and the boss,
An upper structure side sliding plate is installed on the lower surface of the upper structure, and a bearing side sliding plate that causes a slip between the upper structure side sliding plate is installed on the upper surface of the existing bearing,
A method of mobilizing a support portion in a bridge, wherein the existing support is jacked up and mortar is filled in a ridge portion of the lower structural concrete.   4. The bridge portion of the bridge according to claim 2, wherein a part of the boss is left when the boss is cut and removed, and the remaining boss is fitted into a hole provided in the bearing side slide plate. Movable construction method.   A knock-off bolt having a cut fracture surface is provided between the upper structure and the existing support so as to pass through the upper structure-side slide plate and the support-side slide plate and have a fracture surface near both of the slide surfaces. The movable construction method of the support part in the bridge of any one of 2-4.   The friction part between the upper structure side sliding plate and the bearing side sliding plate is adjusted, and these sliding plates are installed, The bearing part of the bridge according to any one of claims 2 to 5, Movable construction method.

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