JP2011241582A - Method for removing temporary support concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for removing temporary support concretes which can reduce noise and oscillation when removing the concrete to restrict the influence to the surrounding environment.SOLUTION: Vinyl sheets 15a are laid on a top end 3 of a bridge pier 1, and temporary support concretes 5 comprising a plurality of blocks 5a and blocks 5b are placed thereon. Vinyl sheets 15b are laid on top faces 25 of the temporary support concretes 5. Joint materials 17 are placed between the adjacent blocks 5a and the blocks 5b. Then, a girder 7 is overhang-erected while being supported by the temporary support concretes 5. After the completion of the girder 7, the blocks 5a placed in the positions where temporary receiving jacks 21 are to be placed are separated by a core drill and so on and removed. The temporary receiving jacks 21 are placed in spaces 19 where the blocks 5a are removed and an upper load is replaced to the temporary receiving jacks 21. The remaining blocks 5b are separated and removed as the blocks 5a.

Description

  The present invention relates to a method for removing temporary bearing concrete.

  Conventionally, when a bridge girder is extended and installed, temporary support concrete is installed at the top of the lower structure to receive the load of the girder temporarily. Then, after the overhanging of the girder is completed, the temporary support concrete is demolished, and the overload received by the temporary support concrete is received by the main support. Temporary bearing concrete is crushed and broken by a breaker by human power. In addition, after fixing the two members whose boundary surfaces are tapered portions with a fixture and using them as temporary bearings, the temporary bearings are disassembled and removed without breaking by releasing the fixation of the two members. A method (for example, see Patent Document 1) or a method in which a plurality of holes are provided inside the temporary bearing and a force is applied to the holes after use to destroy the temporary bearing (for example, see Patent Document 2). ing.

JP-A-49-65629 JP 59-170307 A

  However, if the temporary support concrete is demolished with a breaker, excessive noise and vibration are generated during removal. When demolishing with a core drill or wire saw with low noise, the temporary bearing concrete is crushed, and when the superstructure load is transferred to the main bearing, the bearing elastically deforms and sinks, causing the core drill to get stuck between the concrete and not move. There is.

  The present invention has been made in view of the above-described problems, and its object is to provide a method for removing temporary support concrete that can reduce noise and vibration during removal and suppress the influence on the surrounding environment. That is.

  In order to achieve the above-described object, the present invention includes a step (a) of installing temporary support concrete composed of a plurality of blocks at the top end of a bridge lower structure, and an overhanging construction while supporting a girder with the temporary support concrete. A step (b), a step (c) of installing a temporary receiving jack at the top end of the lower structure and receiving an overload, and a step (d) of removing the plurality of blocks. This is a method for removing the temporary support concrete.

  Between the step (b) and the step (c), if necessary, a step (e) of removing a block installed at a planned installation position of the temporary receiving jack among the plurality of blocks after the completion of the girders. Provided. In this case, in step (c), a temporary receiving jack is installed at the location where the block has been removed in step (e), and the remaining blocks of the plurality of blocks are removed in step (d).

  In the case of providing the step (e), the number and size of the blocks installed in the step (a) are mounted on the remaining blocks after removing the blocks installed at the installation positions of the temporary receiving jacks in the step (e). It is possible to receive a load, and in step (c), it is determined so that the temporary receiving jack can be installed at the place where the block is removed in step (e).

  In the step (a), edge-cutting members are installed on the upper and lower surfaces of the temporary support concrete as necessary. In the step (a), it is desirable to provide a joint material between adjacent blocks.

  In step (d) and step (e), the block to be removed is divided into sizes that can be carried out using a core drill or the like. The temporary receiving jack installed in the step (c) is, for example, a hydraulic jack with a lock function, and locks after receiving the mounted load in the step (c).

  In the present invention, the temporary support concrete is composed of a plurality of blocks. And after extending and installing a girder, the predetermined block which comprises temporary support concrete is removed, a temporary receiving jack is installed, an overload is received, and the remaining blocks are removed. Thereby, temporary support concrete can be divided | segmented by low noise construction methods, such as a core drill, without using a breaker, and can be carried out easily.

  ADVANTAGE OF THE INVENTION According to this invention, the removal method of the temporary support concrete which can reduce the noise and vibration at the time of removal, and can suppress the influence on surrounding environment can be provided.

Side view near the junction of pier 1 and girder 7 Horizontal sectional view of main bearing 13 and temporary bearing concrete 5 Vertical cross section near the joint between pier 1 and girder 7 The figure which shows the process of removing the block 5a of the temporary support concrete 5 The figure which shows the process of installing the temporary receiving jack 21 The figure which shows the process of removing the block 5b of the temporary support concrete 5 The figure which shows the process of removing the temporary receiving jack 21

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view of the vicinity of the joint between the bridge pier 1 and the girder 7, and FIG. 2 is a horizontal sectional view of the main bearing 13 and the temporary bearing concrete 5. 2 is a cross-sectional view taken along arrow AA shown in FIG. FIG. 3 is a vertical cross-sectional view of the vicinity of the joint between the pier 1 and the girder 7. 3 is a cross-sectional view taken along arrows BB shown in FIG.

  As shown in FIGS. 1 to 3, the bridge 2 includes a pier 1, a main support 13, a girder 7, and the like. The girder 7 is supported by a main support 13 provided at the top 3 of the pier 1 which is a lower structure. When building the bridge 2, temporary support concrete 5 is installed at the top 3 of the pier 1. Further, a PC steel bar 9 penetrating the pier 1, the temporary support concrete 5 and the girder 7 is installed.

  As shown in FIGS. 2 and 3, the temporary support concrete 5 is installed on both sides of the main support 13, for example. The temporary support concrete 5 includes a block 5a, a block 5b, a vinyl sheet 15a, a vinyl sheet 15b, a joint material 17 and the like.

  The blocks 5a and 5b are cuboid concrete blocks. A joint material 17 is installed between the adjacent blocks 5 and 5b. A vertical sheath 10 is provided in the block 5a. A PC steel rod 9 is inserted through the sheath 10.

  The vinyl sheet 15a and the vinyl sheet 15b are edge cutting members. The vinyl sheet 15 a is disposed between the lower surface 27 of the temporary support concrete 5 and the top end 3 of the pier 1. The vinyl sheet 15 b is disposed between the upper surface 25 of the temporary support concrete 5 and the lower surface 11 of the beam 7. The vinyl sheet 15 a and the vinyl sheet 15 b are laid on the entire lower surface 27 and upper surface 25 of the temporary support concrete 5.

  In order to construct the bridge 2, first, the pier 1 is formed, and the main support 13 is installed at the top 3 of the pier 1. A PC steel bar 9 is installed on the pier 1. Further, before and after the installation of the main support 13, a vinyl sheet 15a is laid on the top 3 of the pier 1 and the temporary support concrete 5 is installed above the vinyl sheet 15a.

  The temporary support concrete 5 is formed by dividing and placing concrete into a plurality of blocks 5a and 5b. When placing the concrete of the block 5a, it is desirable to insert the PC steel rod 9 through the sheath 10 in advance. A joint material 17 is disposed between the adjacent blocks 5a and 5b. After the temporary support concrete 5 is formed, a vinyl sheet 15 b is laid on the upper surface 25 of the temporary support concrete 5.

  Next, a part of the girder 7 is installed on the temporary support concrete 5, and the bridge pier 1 and the girder 7 are temporarily fixed using the PC steel rod 9 for temporary fixing. Then, the girder 7 is extended and installed. At this time, the vertical load by the girder 7 is supported by the temporary support concrete 5. Further, the load in the horizontal direction is supported by the H steel 12 embedded so as to straddle the beam 7 and the pier 1. The temporary support concrete 5 shall not be crushed even if the maximum weight of the beam 7 is placed. After the overhang construction of the girder 7 is finished, the temporary fixing between the pier 1 and the girder 7 by the PC steel bar 9 is released, and the PC steel bar 9 is removed.

  After removing the PC steel bar 9, the temporary support concrete 5 is removed. FIG. 4 is a diagram illustrating a process of removing the block 5 a of the temporary support concrete 5. In order to remove the temporary support concrete 5, first, the core 23 is removed from the block 5a using a core drill as shown in FIG. The block 5a is vertically divided into two parts by continuously removing the core 23 in the horizontal direction. Then, the divided block 5a is removed.

  The block 5a is edge-cut from the bridge pier 1 by a vinyl sheet 15a and edged from the beam 7 by a vinyl sheet 15b. Therefore, the block 5a has little friction between the pier 1 and the girder 7 and can be easily removed. The block 5a is crushed after being transported to a place where sufficient soundproofing measures have been taken.

  FIG. 5 is a diagram illustrating a process of installing the temporary receiving jack 21. After removing the block 5a, as shown in FIG. 5, the temporary jack 21 is installed in the space 19 where the block 5a is removed. Then, the loading load of the girder 7 is received by the temporary receiving jack 21. The temporary receiving jack 21 is, for example, a hydraulic jack with a lock function. The temporary receiving jack 21 is locked after the replacement of the mounted load is completed.

  FIG. 6 is a diagram illustrating a process of removing the block 5 b of the temporary support concrete 5. In the step shown in FIG. 6, the remaining block 5b of the temporary support concrete 5 is divided by removing the core with a core drill in the same manner as the block 5a shown in FIG.

  Similarly to the block 5a, the block 5b is cut off from the bridge pier 1 by the vinyl sheet 15a and is cut off from the girder 7 by the vinyl sheet 15b. Therefore, the block 5b has little friction between the pier 1 and the girder 7 and can be easily removed. Similarly to the block 5a, the block 5b is crushed after being transported to a place where sufficient soundproofing measures have been taken.

  FIG. 7 is a diagram illustrating a process of removing the temporary receiving jack 21. In the step shown in FIG. 7, the temporary receiving jack 21 is jacked down, the mounted load is received by the main support 13, and the temporary receiving jack 21 is removed. Further, the vinyl sheet 15a and the vinyl sheet 15b are removed.

  The number and size of the temporary support concrete 5 are such that the function of the PC steel rod 9 is not impaired during the overhanging of the girder 7 and the upper load of the girder 7 is received by the remaining block 5b when the block 5a is removed. After the block 5a is removed, the provisional jack 21 is installed so that a space 19 for receiving the load can be secured.

  Thus, in the present embodiment, the temporary support concrete 5 is composed of a plurality of blocks 5a and 5b, and after receiving the loading load of the girder 7 with the temporary receiving jack 21 that is installed by removing the block 5a, The remaining block 5b is removed. By dividing the block 5a and block 5b with a core drill or the like and removing them, the noise and vibration at the time of removal can be reduced compared with the case where large-scale temporary support concrete is destroyed using a breaker. The influence can be suppressed.

  In this embodiment, the block 5a and the block 5b are divided using a core drill, but may be divided using a low noise construction method such as a wire saw, a concrete burster, or a static crushing material. In the present embodiment, the block 5a and the block 5b are divided into upper and lower parts and removed, but the number of divisions and division positions are not limited thereto. The block 5a and the block 5b are divided into sizes that can be carried out and removed as necessary.

  In this embodiment, the horizontal load at the time of extending the girder 7 is received by the H steel 12, but depending on the magnitude of the horizontal force, it may be received by friction between the temporary support concrete 5 and the pier 1. In this case, the vinyl sheet 15a and the vinyl sheet 15b are not installed in order to secure a friction coefficient between the temporary support concrete 5 and the pier 1.

  When the girder 7 is overlaid, the vertical load may be received by the temporary support concrete 5 and the horizontal load may be received by the main support 13. In this case, the H steel 12 shown in FIG. 2 is not installed.

  In the present embodiment, the vinyl sheet 15a and the vinyl sheet 15b, which are edge cutting members, are laid on the entire lower surface 27 and upper surface 25 of the temporary support concrete 5, but the edge cutting member is not laid on the joint material 17 portion. May be. The edge cutting member may be laid so that the block 5a and the block 5b can be edge-cut with the bridge pier 1 or the girder 7. As the edge cutting member, a thin iron plate or joint material may be used in addition to the vinyl sheet.

  In the process shown in FIG. 5, when removing the block 5a, the vinyl sheet 15a on the lower surface 27 of the block 5a and the vinyl sheet 15b on the upper surface 25 are left, but the vinyl sheet 15a and the vinyl sheet 15b are removed simultaneously with the block 5a. Also good. In this case, the temporary receiving jack 21 is directly installed on the top 3 of the pier 1.

  In the present embodiment, the sheath 10 is provided in a part of the blocks 5a of the temporary support concrete 5 and the PC steel rod 9 is inserted. However, the cross-sectional area of the pier 1 is large, and temporary support concrete having a necessary area is arranged. However, if there is still space and the PC steel bar does not interfere inside the girder even if the PC steel bar is placed outside the temporary support concrete, install the temporary support concrete avoiding the PC steel bar. Also good.

  The number and shape of the blocks constituting the temporary support concrete are not limited to those described above. The number and shape of the blocks that make up the temporary support concrete do not impair the function of the PC steel bar during the overhanging of the girder, and when the block is partially removed, the remaining blocks can receive the overload of the girder. Any space that can secure a space for receiving a load with a temporary receiving jack after removing a part of the block may be used.

  In the present embodiment, the provisional jack 21 is installed in the space 19 from which some of the blocks 5a among the blocks constituting the temporary support concrete 5 are removed and the load is changed, and then the remaining blocks 5b are removed. If the cross-sectional area of the pier 1 is large and there is still space after placing the temporary support concrete in the required area, install the temporary jack without changing the block and change the load. You may remove the block.

  As mentioned above, although preferred embodiment of the removal method of the temporary support concrete concerning this invention was described referring an accompanying drawing, this invention is not limited to this example. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

1 ... …… Bridge pier 3 ……… Top 5 ……… Temporary bearing concrete 7 ………… Girder 11, 27 ……… Bottom surface 13 ……… This bearing 15a, 15b ……… Vinyl sheet 17 ……… Joint material 21 ……… Temporary jack 25 ……… Top

Claims (7)

A step (a) of installing temporary support concrete composed of a plurality of blocks at the top of the bridge substructure;
A step (b) of extending and supporting the beam with the temporary support concrete;
A step (c) of installing a temporary receiving jack on the top end of the lower structure and receiving an overload;
Removing the plurality of blocks (d);
A method for removing temporary bearing concrete, comprising: Between the step (b) and the step (c), the method further includes a step (e) of removing a block installed at a position where the temporary receiving jack is to be installed among the plurality of blocks after completion of the beam. ,
In the step (c), the temporary receiving jack is installed at the place where the block is removed in the step (e),
The method for removing temporary support concrete according to claim 1, wherein in the step (d), the remaining blocks of the plurality of blocks are removed. The number and size of blocks installed in the step (a) are as follows:
In the step (e), after removing the block installed at the planned installation position of the temporary receiving jack, it is possible to receive an overload with the remaining blocks,
The method for removing temporary support concrete according to claim 2, wherein in step (c), the temporary support concrete is determined so that the temporary support jack can be installed at a location where the block is removed in step (e).   The method for removing temporary support concrete according to any one of claims 1 to 3, wherein, in the step (a), members for edge cutting are installed on an upper surface and a lower surface of the temporary support concrete.   The method for removing temporary support concrete according to any one of claims 1 to 4, wherein a joint material is provided between the adjacent blocks in the step (a).   The method for removing temporary support concrete according to any one of claims 1 to 5, wherein, in the step (d) and the step (e), the block to be removed is divided into sizes that can be carried out.   The temporary support jack according to any one of claims 1 to 6, wherein the temporary support jack is a hydraulic jack with a lock function, and locks after receiving an overload in the step (c). How to remove concrete.

Images