JP3861100B1 - Bridge girder dismantling method - Google Patents

Abstract

[PROBLEMS] When a girder bridge cannot be used, especially when it is impossible to use the space under the girder, the construction method is limited, the construction cost is high, and the construction period is generally long. Furthermore, in the case of river bridges, there was a problem that construction was not possible throughout the year due to restrictions such as the construction conditions for drought periods.
[MEANS FOR SOLVING PROBLEMS] A portal tower is built near the abutments or piers at both ends of a bridge girder, a section for cutting and dividing the bridge girder body is determined, and the head of the portal tower and the vicinity of the position where the bridge girder body is divided are divided into several sections. Fixed with a cable, suspended in advance with a truck crane installed on the back of the bridge girder that disassembles the central part of the section to be cut and divided, cut the central part in that state, and cut the central part A bridge girder dismantling method is provided, in which the bridge girder is removed by a truck crane, and then the remaining part of the bridge girder is repeatedly subjected to temporary suspension, cutting, and removal operations for each section to be cut and divided into the ends.
[Selection] Figure 1

Description

  The present invention relates to the removal of a bridge girder.

The removal method of the conventional girder bridge differs greatly depending on whether the space under the girder can be used due to the location conditions. In general, (1) a method of assembling and dismantling a support work in the space under the girder, and (2) a removal method using a large truck crane are adopted. There are no restrictions on urban viaducts, maritime bridges or under-girder space use, but for girder bridges with heights above 20m above ground, the dismantling methods (1) and (2) are based on safety, construction period, and cost. Hiring is often difficult.
As a conventional method of dismantling without using the under-girder space, (3) removal method using a large truck crane placed on the girder between adjacent diameters and on the attachment road, (4) removal method using a large crane ship at the offshore bridge, ▲ 5 ▼ There is a removal method with a truck crane using a jetty created in parallel with the existing bridge girder. (For example, refer nonpatent literature 1, patent literature 1)

Hereinafter, the conventional removal method will be described with reference to FIGS. 3, 4, 5, 6, 7, and 8. 3 is a method of (1), FIG. 4 is a method of (2), FIG. 5 is a method of (3), FIG. 6 is a method of (4), and FIG. It is.
“Bridge Removal Technology Manual” Hokuriku Bridge Removal Technology Association 2000 p. 46 JP H10-280328 Japanese Patent Application No. 2003-357029

The conventional girder bridge removal method (1) requires a large amount of temporary materials necessary for assembling for supporting works, many craftsmen necessary for assembling, and a period for disassembling the supporting works. Safe equipment is necessary. Therefore, the construction cost is high and the construction period is generally long. Especially, river bridges have construction conditions only for the drought period, and it is difficult to construct them throughout the year.
The removal method {circle around (2)} is a method used for removing bridges between relatively short meridians in a short period of time. However, it is a condition that an access path for a large crane is secured as close as possible to the bridge girder to be removed.
The removal method (3) is limited to relatively small span girder bridges due to problems such as the strength of the girder bridge carrying the crane. The removal method (4) is mainly used for large-scale offshore bridges, but requires a water depth that can be transported by a large crane ship.
In the case of removal method (5), this method is used for river bridges and offshore bridges where the water depth is not secured, but it is a method to create a temporary pier that can withstand heavy machinery work such as truck cranes and remove the bridge girder. . River bridges have the disadvantage that the pier installation period is limited to the dry season.
As described above, the disadvantage of the conventional construction method is that it largely depends on the conditions at the site, so that the variation in construction days, construction costs, construction time, etc. is large.

  The present invention is intended to solve the problems of the conventional construction method, and aims to carry out the girder bridge removal operation safely in a short period of time at a low construction cost.

In order to achieve the above object, the present invention is provided as a construction method suitable for any conditions at the bridge point, particularly as an effective construction method for removing a continuous urban viaduct that is about to be renewed.
In this construction method, the bridge piers to be dismantled and the gate towers are installed on the abutments, and the anchors fixed to the bridge piers between adjacent diameters and the heads of the portal towers are fixed with a lanyard, and the bridge girder is near the position where it is cut and divided Fix the head of the tower tower with a diagonal cable and finish the setup. In this state, a method is provided in which the bridge girder is cut at a predetermined position and lifted and removed by a crane while the section to be cut by the truck crane arranged on the bridge girder between adjacent diameters is temporarily suspended.
The cutting points are allocated so that the weight can be lifted by a self-propelled truck crane, and the member cutting / removing work starts from the center of the bridge, proceeding to the end side sequentially, and the bridge girder cutting member is placed on the waiting truck. Direct loading and unloading.

  If the strength of the bridge girder on which the truck crane is loaded is insufficient, a PC cable is placed in the girder between the spans to reinforce the stress.

  As described above, the bridge girder removal method of the present invention is less affected by the bridge girder bridge conditions than the conventional method.

  The temporary material to be carried in is small and relatively light, and it is characterized by extremely short work and extremely little work at high places. Therefore, safety is high and construction costs can be significantly reduced compared to conventional methods. .

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

The tower-type tower equipment 3 is assembled, and the rear cable 4 is stretched from the head of 3 and fixed to an anchor 6 provided on a bridge pier between adjacent diameters or an attachment road.

The bridge girder body 1 is fixed with a plurality of slanting members 5 from the head of the portal tower 3 to the cut portion 7 to prepare for the division and removal of one.

Next, in a state where the portion of the bridge girder 1 to be removed by the self-propelled crane 8 is temporarily suspended, 7 portions are cut and lifted and removed at 8. The capacity of 8 is determined by the working radius based on the weight of 1 division.

The divided and removed girders 1 are subjected to secondary cutting on the back surface or sequentially loaded and unloaded on the transport truck 9 to complete the removal operation 1.

Hereinafter, for the remaining part of the bridge girder, the operation of temporarily suspending, cutting, and removing is repeated for each section that is sequentially cut and divided toward the end side.

When the strength of the bridge girder between the spans on which the crane is loaded is insufficient, the span is reinforced with a PC cable.

Setup explanatory drawing of bridge girder removal showing an embodiment of the present invention Explanatory drawing of the bridge girder bridge removal situation showing the embodiment of the present invention Explanatory drawing of split removal work on support with conventional removal method (1) General method of removing bridge girder with truck crane using conventional removal method (2) Method of removing the bridge girder by placing the truck crane between adjacent diameters with the conventional removal method (3) How to remove bridge girder with crane ship by conventional removal method (4) A method of removing a bridge girder with a truck crane by installing a temporary pier in the conventional removal method (5) Conceptual diagram of reinforcement using PC cables for bridge girders

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bridge girder body 2 Pier, abutment 3 Gate type steel tower equipment 4 Rear cable 5 Slant hanging material 6 Anchor for anchoring rear cable 7 Cutting position 8 Self-propelled truck crane 9 Transport truck 10 Supporting work 11 Temporary pier 12 Crane ship 13 Reinforcement PC cable

Claims (1)

Each built portal tower in abutment or near abutment at both ends of the girder to be dismantled in urban continuous viaduct, anchor and each portal tower provided respectively on the other pier or installing road span on both sides of the bridge girder axial tension to Hikaesaku respectively between the head, the fixed by the end cable and the number Article respective near segment for cutting division of the head and the bridge girder of the gantry tower, bridge girder to the dismantling PC cable is placed on the bridge girder between the front side of the direction, and the central part of the section to be cut and divided is temporarily suspended by a self-propelled truck crane arranged on the front side girder of the axial direction. The central part is cut in the state, the cut central part is removed by the self-propelled truck crane, and then the remaining part of the bridge girder is temporarily suspended for each of the sections to be cut and divided sequentially. Cut off , The task of repeating the operations of removal and set, after the work end of the set, is moved on the bridge deck adjacent the self-propelled truck crane, by sequentially repeating the operations of the set, urban continuous viaduct Bridge girder dismantling method, characterized by dismantling the bridge girder in

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