JP6416539B2 - Bridge girder replacement method - Google Patents

Description

  The present invention relates to a bridge girder replacement method.

As repair work for an aging bridge, the bridge girder may be replaced while the existing pier remains.
In conventional bridge girder replacement work, it is common to install a new bridge girder after removing the existing girder using a large crane.

  However, in the conventional replacement method, it is necessary to secure a space for installing a large crane, a temporary storage space for the bridge girder, etc. around the bridge (under the girder). When sufficient space around the bridge could not be secured, it was necessary to divide the bridge girder and replace it with a small crane.

  As a bridge girder replacement method when the installation space for a large crane cannot be secured in the ground area around the bridge, for example, in Patent Document 1, an erection gutter is installed above the existing bridge girder along the bridge axis direction, The construction method which removes an existing bridge girder with the suspension device which moves this erection gutter, and constructs a new bridge girder with the said suspension device is disclosed.

  Further, in Patent Document 2, a new bridge girder is arranged over another bridge girder adjacent to the existing bridge girder before and after the existing bridge girder, and the existing bridge girder is installed using a suspension device installed on the new bridge girder. A method is disclosed in which a new bridge girder is lowered and horizontally mounted on the pier after being lowered and removed from the pier.

JP 2003-253623 A JP 2009-052306 A

  The bridge girder replacement method described in Patent Literature 1 and Patent Literature 2 has a limitation in shortening the construction period because the new bridge girder is constructed after removing the existing bridge girder. If the construction period of the bridge girder replacement work becomes longer, the period of closed roads will be prolonged, so the impact on the neighborhood will be great.

  From such a viewpoint, an object of the present invention is to provide a bridge girder replacement method that enables early replacement work of a bridge girder.

In order to solve the above problems, the bridge girder replacement method of the present invention includes a jack disposing step of disposing a jack below an existing bridge girder, supporting the existing bridge girder by the jack, and a fulcrum portion of the existing bridge girder. A supporting step of cutting, a bridge girder arranging step of arranging a new bridge girder on the existing bridge girder, and a construction step of lowering the existing bridge girder and the new bridge girder by the jack and erection of the new bridge girder on a pier. Is. In the bridge girder arranging step, a plurality of the newly installed bridge girders are connected to form a bridge body constructed over the plurality of the bridge piers.

According to such a bridge girder replacement method, the removal work of the existing bridge girder and the construction work of the new bridge girder are simultaneously performed, so that the construction period can be shortened.
Therefore, it is possible to shorten the period for which the bridge is closed, and to minimize the influence on transportation.

Further, in the bridge deck disposed step, by connecting a plurality of the new bridge deck, it is possible to replace bridged order to form a bridge member which is bridged over a plurality of the pier, a multi-span at the same time Ri, it is possible to further construction period shortened.

  Moreover, if a transport vehicle is arranged below the existing bridge girder, and the existing bridge girder is placed on the transport vehicle in the erection process, the time required for securing a temporary storage space for the existing bridge girder, transshipment, etc. Can be omitted.

  According to the bridge girder replacement method of the present invention, the bridge girder replacement work can be performed at an early stage.

(A)-(d) is a front view which shows the operation | work condition of the bridge girder replacement construction method of this embodiment. (A) is the cross-sectional view of (b) of FIG. 1, (b) is the cross-sectional view of (d) of FIG.

In the present embodiment, as shown in FIG. 1, a bridge girder replacement method for replacing the existing bridge girder 4 of the existing bridge 3 with the bridge body 1 will be described.
The bridge body 1 is formed by connecting a plurality of new bridge girders 2, 2, and 2. The bridge body 1 before the replacement is formed in a warped state so that both end portions are located on the upper side of the central portion in the bridge axis direction.

In this embodiment, the existing bridge girder 4 for three spans supported by the four piers 5, 5,.
In addition, the length (number of spans) of the existing bridge girder 4 to be replaced is not limited.

  The existing bridge girder 4 is formed of so-called ordinary concrete. In addition, the material of the existing bridge girder 4 is not limited.

  The bridge girder replacement method includes a jack installation process, a support process, a bridge girder installation process, and an installation process.

  The jack disposing step is a step of disposing a plurality of first jacks 6, 6,... Below the existing bridge girder 4 as shown in FIG.

In the present embodiment, a total of four first jacks 6, 6,... Are arranged between the piers 5 adjacent in the bridge axis direction. Specifically, two rows (see FIG. 2A) of two rows of jacks composed of two first jacks 6 and 6 arranged at an interval in the bridge axis direction are arranged along the bridge crossing direction.
Therefore, in this embodiment, 12 first jacks are arranged for the existing bridge girder 4 (3 diameters) to be replaced.

The first jack 6 is disposed close to the pier 5. That is, the first jacks 6, 6,... Arranged between the pair of bridge piers 5, 5 are arranged at intervals in the bridge axis direction.
The arrangement and number of the first jacks 6 are not limited.

  In the present embodiment, a large hydraulic jack (stage jack) is used as the first jack 6. The configuration of the first jack 6 is not limited.

  In the supporting step, as shown in FIGS. 1A and 1B, the existing bridge girder 4 is supported by the first jack 6, and the fulcrum portion (joint portion with the pier 5) 7 of the existing bridge girder 4 is cut. It is a process.

The existing bridge girder 4 is supported from below by a first jack 6 disposed below (Fig. 1 (a)). When the first jack 6 is extended to support the existing bridge girder 4, the fulcrum portion 7 of the existing bridge girder 4 is cut and removed ((b) of FIG. 1).
By removing the fulcrum part 7, the existing bridge girder 4 is divided into a plurality of divided bridge girders 4a, 4a, 4a shorter than the interval between the piers 5.

The bridge girder arranging step is a step of arranging the new bridge girder 2, 2 and 2 on the existing bridge girder 4 as shown in FIG.
In this embodiment, the second jacks 8, 8,... Are arranged on the existing bridge girder 4, and the new bridge girders 2, 2, 2 are arranged on the second jacks 8, 8,.

For the new bridge girder 2, a box girder (a precast member in which a floor slab and a U girder are combined) formed of ultra high strength fiber reinforced concrete is used. Therefore, the new bridge girder 2 is lighter than the existing bridge girder 4 and existing floor slab (not shown) made of ordinary concrete.
In addition, the material which comprises the new bridge girder 2 is not limited.

Each new bridge girder 2 is supported by four second jacks 8, 8,... As shown in FIG. 1 (b) and FIG.
The number of the second jacks 8 that support the new bridge girder 2 is not limited.

  When the new bridge girders 2, 2, 2 are arranged on the existing bridge girder 4, the new bridge girders 2, 2, 2 are connected to form the bridge body 1. In the present embodiment, the three new bridge girders 2, 2, and 2 are connected to form the bridge body 1, but the number of the new bridge girders 2 that form the bridge body 1 is not limited.

  The bridge body 1 is formed so that both end portions are positioned above the center portion in the bridge axis direction. That is, while the new bridge girder 2 at the center is horizontally supported, the new bridge girders 2 and 2 arranged on both sides (left and right in FIG. 1B) have the extension height of the second jacks 8 and 8. By adjusting, it is inclined so as to become lower toward the center side, and is formed to be convex downward as a whole.

The newly installed bridge girders 2 are connected to each other in a state where a filling material (not shown) is interposed at the joint (butting portion).
When the new bridge girders 2 are connected to each other, a tension force is introduced into a tension member (not shown) inserted through the bridge body 1 (straddling the three new bridge girders 2, 2, 2).

By introducing a tension force to the tension material, the end faces of the newly installed bridge girders 2 and 2 are pressure-bonded (total compression structure).
In addition, the material which comprises a tension | tensile_strength is not limited, For example, what is necessary is just to use PC steel wire, PC strand, a PC steel rod, etc.

  Since the tension members are arranged in the lower part of the bridge body 1, when a tension force is introduced into the tension members, downward force acts on both ends of the bridge body 1 in the bridge axis direction. Since it is supported by the two jacks 8, 8, the bridge body 1 is maintained in a warped state.

  The erection process is a process of removing the existing bridge girder 4 and placing the bridge body 1 on the plurality of piers 5, 5,.

In the erection step, the bridge body 1 is lowered together with the existing bridge girder 4 by contracting the first jacks 6, 6,... As shown in FIG.
At this time, the twelve first jacks 6, 6,... Are controlled so as to descend simultaneously through a control system (not shown).

  The control system collects jack stroke and jack reaction force data of each first jack 6 and performs management based on this data. If an error occurs during descending, all the first jacks 6, 6,... Are stopped and corrected.

  Moreover, on the existing bridge girder 4, the 2nd jacks 8, 8, ... are contracted, and the bridge body 1 is lowered. The second jacks 8, 8,... May be contracted after the descent of the existing bridge girder 4 by the first jacks 6, 6,. May be.

  When the bridge body 1 is lowered, the contraction amount of the second jack 8 disposed on the end side in the bridge axis direction of the bridge body 1 is larger than the contraction amount of the second jack 8 disposed on the center side. Adjust while adjusting. If it carries out like this, as shown to (d) of FIG. 1 and (b) of FIG. 2, when the bridge body 1 is constructed on the piers 5, 5, ..., the upper surface of the bridge body 1 will be in a flat state.

  When the bridge body 1 is installed on the piers 5, 5,..., The control is performed while simultaneously controlling the twelve second jacks 8 using a control system (not shown).

  The control system collects jack stroke and jack reaction force data of each second jack 8 and performs management based on this data. If an error occurs during lowering of the second jack, all the second jacks 8, 8,... Are stopped and corrected.

  The divided bridge girders 4a, 4a, 4a lowered along with the piers 5, 5,... Of the bridge body 1 are placed on the transporting vehicles 9, 9, 9 previously disposed below and carried out.

In the present embodiment, the transport vehicle 9 is disposed between the first jacks 6, and the split bridge girder 4 a is moved from the first jacks 6, 6,. Shall be transshipped.
In addition, the transshipment method to the conveyance vehicle 9 of the divided bridge girder 4a is not limited.

  According to the bridge girder replacement method of the present embodiment, the removal of the existing bridge girder 4 and the erection of the bridge body 1 (new bridge girder 2, 2, 2) are performed at the same time, so the construction period can be shortened. Therefore, the construction period of the bridge girder replacement work can be shortened, and consequently the period of closed roads can be shortened.

Moreover, the construction period can be further shortened by simultaneously switching between the multiple diameters.
In addition, since a transport vehicle for carrying out the existing bridge girder 4 is disposed below the existing bridge girder 4, the existing bridge girder 4 removed from the pier and lowered is placed on the transport vehicle as it is, and then carried out. can do. For this reason, the labor of the work can be greatly reduced.

  Further, since the bridge body 1 is installed so that the upper surface is flat, the fulcrum reaction force acting on the plurality of piers 5, 5,. Therefore, it is possible to omit or reduce the labor for reinforcing the pier 5 and the like, and it is possible to shorten the construction period and reduce the construction cost.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and the above-described components can be appropriately changed without departing from the spirit of the present invention.

For example, the form of the pier of the existing bridge is not limited to the T-shaped pier, and may be a wall-type pier, for example.
The form of the bridge girder (existing bridge girder and new bridge girder) is not limited, and a box girder, I-shaped girder, plate girder, etc. may be appropriately selected and adopted.

  In the embodiment, the fulcrum part of the existing bridge girder is cut in the support process before the bridge body forming process, but the cutting timing of the fulcrum part of the existing bridge girder is not limited as long as it is before the installation process.

  The bridge body does not necessarily have to be formed in a warped state so that both end portions are located above the center portion.

  In the above embodiment, the case where the first jack is arranged on the ground has been described. However, by installing the first jack on the transporting vehicle (transporting machine), the work of transshipping the removed existing bridge girder to the transporting vehicle is performed. It may be omitted.

1 Bridge 2 New bridge girder 3 Existing bridge 4 Existing bridge girder 5 Bridge pier (existing pier)
6 First jack (jack)
7 fulcrum part 8 second jack 9 transport vehicle

Claims (2)

A jack placement step of placing a jack below the existing bridge girder;
While supporting the existing bridge girder with the jack, a supporting step of cutting the fulcrum part of the existing bridge girder,
A bridge girder arranging step of arranging a new bridge girder on the existing bridge girder;
A bridge girder replacement method comprising lowering the existing bridge girder and the new bridge girder by the jack, and a erection process for erection of the new bridge girder on a pier ,
In the bridge girder arrangement step, a bridge girder replacement method is formed by connecting a plurality of the newly installed bridge girders to form a bridge body constructed across the plurality of the bridge piers. Place a transport vehicle below the existing bridge girder,
The bridge girder replacement method according to claim 1, wherein, in the erection step, the existing bridge girder is placed on the transport vehicle.

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