JP2003034911A - Replacing method for bridge girder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a replacing method for a bridge girder by which replacing work of the bridge girder can be quickly executed without using a large crane. SOLUTION: In a state that an existing bridge girder 1 erected on adjacent piers in the bridge axis direction is supported from the lower direction by jacks 4a laid on trucks 4b, the both ends of the existing bridge girder 1 is cut off so as to become shorter than the span L of the bridge piers 3, and at the same time, the replacing work of the bridge girder is executed by a replacing preparing process to construct a new bridge girder 2 to be erected on the bridge piers 3 on the existing girder 1, a bridge girder lowering process to lower the existing bridge girder 1 by the jacks 4a in a state that the new bridge girder 2 is laid on the existing bridge girder 1, a new bridge girder erecting process to erect the new bridge girder 2 on the bridge piers 3, and an existing bridge girder carrying-out process to carry out the existing bridge girder 1 supported by the jacks 4a.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a bridge girder replacement method.

[0002]

2. Description of the Related Art Conventionally, when replacing an existing bridge girder installed on bridge piers adjacent to each other in the bridge axis direction, the following procedure has been performed (see FIGS. 1, 5 and 6). FIG. 1 illustrates the procedure of the bridge girder replacement method according to the present invention. However, the procedure shown in FIG. 1 is common to the conventional bridge girder replacement method, so here, the conventional bridge girder replacement method is used. Reference as an explanation of the procedure of the replacement method). The existing bridge girder 1 erected on the piers 3 and 3 is used as a carriage 4b.
It is supported from below by the jack 4a installed above (FIG. 1 (b)). Both ends of the existing bridge girder 1 are cut off so that the existing bridge girder 1 is shorter than the span L (distance between the front faces of the piers) of the piers 3 and 3 (Fig. 1 (c)). The jack 4a is operated to lower the existing bridge girder 1 (Fig. 5 (a)). With the existing bridge girder 1 supported by the jack 4a, the existing bridge girder 1 is carried out by the carriage 4b (FIG. 5 (b)). A new bridge girder 2 (Fig. 5 (b)) constructed on the bridge girder adjacent to the bridge girder replacement position is collectively lifted by the large crane 12 and erected on the piers 3, 3 (Fig. 5 (c), Fig. 6).

[0003]

However, in the above-mentioned method, the new bridge girder 2 can be erected on the piers 3 and 3 only after the existing bridge girder 1 has been removed, so that it takes time to perform the replacement work. Takes. Also, a large crane 1
In the state in which the heavy and long new bridge girder 2 is hung in a lump at the same time, the work of turning, moving and erection to a predetermined position is
Very difficult. Furthermore, in urban areas, there are many cases where buildings are close to the work area and roads are installed under the bridge girders. Therefore, the construction work of the new bridge girder 2 by the large crane 12 becomes more difficult. . Further, when a road is installed under the bridge girder, a large-scale traffic regulation is often performed to secure a work area for the large-sized crane 12, which may cause a traffic congestion.

In view of the above problems, the present invention provides a bridge girder replacement method that can quickly perform bridge girder replacement work, and can also perform bridge girder replacement work without using a large crane. The task is to do.

[0005]

In order to solve such a problem, the bridge girder replacement method according to claim 1 is to mount an existing bridge girder installed on bridge piers adjacent to each other in the bridge axis direction on a carriage. With the jacks supported from below, both ends of the existing bridge girder are cut off so as to be shorter than the span of the bridge pier, and a new bridge girder to be built on the bridge pier is constructed on the existing bridge girder. A replacement preparation step, a bridge girder lowering step of lowering the existing bridge girder by the jack while the new bridge girder is placed on the existing bridge girder, and a new bridge girder erection step of erection of the new bridge girder on the pier And an existing bridge girder unloading step of unloading the existing bridge girder supported by the jack.

[0006] Such a bridge girder replacement method is a work in which an existing bridge girder and a new bridge girder constructed on the bridge girder are collectively lowered by a jack, the existing bridge girder is removed from the pier and the new bridge girder is erected on the pier. And are done in parallel. Therefore, the time required for the replacement work can be significantly reduced. In addition, since a new bridge pier is constructed on the existing bridge girder and the jack supporting the existing bridge girder from below lowers the existing bridge girder and the new bridge girder, a large crane for suspending the new bridge girder is not required.

According to a second aspect of the present invention, there is provided a bridge girder replacement method in which an existing bridge girder installed on bridge piers adjacent to each other in the axial direction of the bridge is supported from below by a jack mounted on a trolley. Both ends of the existing bridge girder are cut off so as to be shorter than the existing bridge girder, and a new bridge girder to be erected on the pier is constructed on a sending platform installed adjacent to the existing bridge girder, and the new bridge girder is installed to the existing bridge girder. A preparatory step of sending out onto the bridge girder, a bridge girder descending step of lowering the existing bridge girder by the jack while the new bridge girder is placed on the existing bridge girder, and erection of the new bridge girder on the pier A new bridge girder erection step and an existing bridge girder unloading step of unloading the existing bridge girder supported by the jack.

[0008] Such a bridge girder replacement method involves simultaneously dropping the existing bridge girder and the new bridge girder with a jack, removing the existing bridge girder from the pier, and erection of the new bridge girder on the pier. It is something to do. Further, since the construction work of the new bridge girder is carried out on the sending base installed in the position adjacent to the existing bridge girder to be removed, it can be carried out in parallel with the work of cutting off the end portion of the existing bridge girder. Therefore, the time required for the replacement work can be shortened.
Moreover, since the existing bridge girder and the new bridge girder are lowered by the jack to switch the bridge girder, a large crane for suspending the new bridge girder is unnecessary.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a bridge girder replacement method according to the present invention will be described below in detail with reference to the accompanying drawings. Note that the following embodiments assume a case where bridge girders are continuously erected like a viaduct that is often found on expressways in urban areas (see FIG. 1A), but the present invention is not limited to this. However, the bridge girder replacement method according to the present invention can be applied to the case of replacing a bridge or an overpass.

1 and 2 are side views for explaining each step of the bridge girder replacement method according to the present invention. Hereinafter, each step will be described in detail.

(Rebuilding Preparation Step) The rebuilding preparation step is shown in FIG.
As shown in (a), (b), (c), and FIG. 2 (a), the existing bridge girder 1 erected on the bridge piers 3 adjacent in the bridge axis direction is mounted on the carriage 4b.
The existing bridge girder 1 should be shorter than the span L of the pier 3 while being supported from below by the jack 4a placed on top.
Both ends of the bridge are cut off and a new bridge girder 2 to be erected on the bridge pier 3 is constructed on the existing bridge girder 1.

As shown in FIG. 1 (b), while removing the balustrade and the ground cover on the bridge girder, the existing bridge girder 1 erected on the bridge piers 3, 3 adjacent in the bridge axial direction is supported from below by the jack 4a. To do. The jack 4a is installed on the carriage 4b. In this state, as shown in FIG. 1 (c), both ends of the existing bridge girder 1 are cut with a wire saw so that the existing bridge girder 1 is shorter than the span L (distance between the front faces of the piers) of the piers 3 and 3. The device is cut, and the cut site is removed using the crane 10 or the like.

As shown in FIG. 2A, a new bridge girder 2 is constructed on the existing bridge girder 1 in parallel with or after the above-mentioned respective works. Since the new bridge girder 2 is erected on the piers 3 and 3, it has a girder length adapted to this. Also, a bearing 3b for the new bridge girder 2 formed on the pier 3 (see FIG. 4)
The new bridge girder 2 so that the end of the new bridge girder 2 is located directly above
To build. The new bridge girder 2 may be constructed by assembling a plurality of precast members 2a made of steel or concrete, or may be constructed by cast-in-place concrete. Further, in this embodiment, prior to the rebuilding preparation process,
As shown in FIG. 4, the support 3b of the new bridge girder 2 is constructed at a position adjacent to the support 3a of the existing bridge girder 1.

(Bridge girder descending process) The bridge girder descending process is shown in FIG.
As shown in (b), the existing bridge girder 2 is lowered by the jack 4a while the new bridge girder 2 is placed on the existing bridge girder 1.

When the construction of the new bridge girder 2 is completed, with the new bridge girder 2 placed on the existing bridge girder 1, the jack 4a is operated to lower the existing bridge girder 1. Since both ends of the existing bridge girder 1 have been cut off so as to be shorter than the span L of the bridge piers 3 and 3, lower the existing bridge girder 1 between the piers 3 and 3 as shown in Fig. 2 (b). You can Moreover, since the end of the new bridge girder 2 is constructed to be placed on the bearing 3b formed on the upper surface of the piers 3 and 3, if the existing bridge girder 1 is lowered, the new bridge girder 2 will be inevitably moved. It will be positioned,
If necessary, the existing bridge girder 1 and the new bridge girder 2 are lowered while making fine adjustments in the bridge axis direction or in the direction perpendicular to the bridge axis. Further, when a plurality of jacks are installed as in the illustrated embodiment, all the jacks have the same descent speed, and the existing pier 1 and the new bridge girder 2 mounted thereon are kept horizontal. To lower.

(New bridge girder erection process) In the new bridge girder erection process, as shown in FIG. 2 (b), the new bridge girder 2 is erected on the bridge pier 3. The new bridge girder 2 lowered to a predetermined height in the above-mentioned bridge girder lowering step is supported by the support 3b of the pier 3 (Fig. 4).
(See (b) and (c)), and fix the new bridge girder 2 to the pier 3,
Install in 3.

(Existing Bridge Girder Unloading Step) In the existing bridge girder unloading step, as shown in FIG. 2C, the existing bridge girder 1 is unloaded. After constructing the new bridge girder 2 on the piers 3 and 3, the existing bridge girder 1 is lowered to a predetermined height by the jack 4a, and the existing bridge girder 1 is placed on the jack 4a, and is carried out to a predetermined unloading place by the trolley 4b. To do. This completes the work of replacing the existing bridge girder 1.

As described above, in the bridge girder replacement method according to the present embodiment, the existing bridge girder 1 and the new bridge girder 2 constructed on the existing bridge girder 1 are collectively lowered by the jack 4a, and the existing bridge girder 1 is
The work of removing the pier from the piers 3 and 3 and the work of constructing the new bridge girder 2 on the piers 3 and 3 are performed in parallel.
That is, the work for removing the existing bridge girder 1 and the work for constructing the new bridge girder 2 can be performed at the same time, so that the time required for the replacement work can be significantly reduced.

Since the new bridge pier 2 is constructed on the existing bridge girder 1 and the jack 4a supporting the existing bridge girder 1 from below lowers the existing bridge girder 1 and the new bridge girder 2 together,
There is no need for a large crane to suspend the new bridge girder 2. Therefore, for example, when a road is provided below the viaduct, it is possible to minimize traffic restrictions on vehicles passing through this road.

In the above-mentioned embodiment, the example of constructing the new bridge girder 2 on the existing bridge girder 1 to be removed is shown. However, as shown in FIGS. 3 (a) and 3 (b), it is adjacent to the existing bridge girder 1. After constructing the new bridge girder 2 on the sent-out gantry 2b installed as above, the new bridge girder 2 may be sent out onto the existing bridge girder 1 by the sending-out device 2c. In this case, since the new bridge girder 2 can be constructed in parallel with the work of cutting off both ends of the existing bridge girder 1, it is possible to shorten the time required for the replacement work.

Further, the work of removing the balustrade or the like and the work of installing the support 3b for the new bridge girder 2 may be appropriately performed in consideration of the situation of the construction site and the structural type of the bridge girder.

[0022]

According to the bridge girder replacement method of the present invention,
Since the work for removing the existing bridge girder and the work for constructing the new bridge girder can be performed at the same time, the time required for the replacement work can be significantly reduced.

Since the existing bridge girder and the new bridge girder are collectively lowered by the jack that supports the existing bridge girder from below,
No large crane is required to suspend the new bridge girder.
Therefore, especially in an urban area, for example, when a road is provided below the viaduct, traffic restrictions on vehicles passing through this road can be minimized.

[Brief description of drawings]

FIG. 1 is a side view illustrating a procedure of a rebuilding preparation step in a bridge girder replacement method according to the present invention.

FIG. 2 (a) is a side view illustrating a procedure of a replacement preparation process subsequent to FIG. 1, (b) is a side view illustrating a descent process and a new bridge girder erection process, and (c) is an existing bridge girder unloading process. It is a side view explaining.

FIG. 3 is a side view illustrating another procedure of the reassembling preparation step.

FIG. 4 is a sectional view showing a support portion.

FIG. 5 is a side view illustrating a procedure of a conventional bridge girder replacement method.

FIG. 6 is a side view illustrating the procedure following FIG.

[Explanation of symbols]

1 Existing bridge girder 2 New bridge girder 2a Precast member 2b Sending stand 2c sending device 3 piers 4a jack 4b trolley

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroyasu Inamori             1-25-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Taisei             Construction Co., Ltd. F-term (reference) 2D059 BB39 CC03 CC04 CC08 GG41

Claims (2)

[Claims] 1. In a state in which an existing bridge girder installed on bridge piers adjacent to each other in the axial direction of the bridge is supported from below by a jack placed on a truck, the bridge girder of the existing bridge girder is made shorter than the span of the bridge pier. While excising both ends, a preparatory step of constructing a new bridge girder to be erected on the bridge pier on the existing bridge girder, with the new bridge girder placed on the existing bridge girder,
A bridge girder descending step of lowering the existing bridge girder by the jack, a new bridge girder erection step of erection of the new bridge girder on the pier, and an existing bridge girder unloading step of unloading the existing bridge girder supported by the jack. Bridge girder replacement method characterized by. 2. An existing bridge girder that is erected on bridge piers that are adjacent to each other in the bridge axis direction is supported from below by a jack placed on a trolley so that the bridge pier of the existing bridge girder is shorter than the span of the bridge pier. A reconstructing preparatory step of cutting off both ends and constructing a new bridge girder to be erected on the bridge pier on a sending platform installed adjacent to the existing bridge girder, and sending the new bridge girder onto the existing bridge girder. , With the new bridge girder placed on the existing bridge girder,
A bridge girder descending step of lowering the existing bridge girder by the jack, a new bridge girder erection step of erection of the new bridge girder on the pier, and an existing bridge girder unloading step of unloading the existing bridge girder supported by the jack. Bridge girder replacement method characterized by.