JP3830362B2 - Overhang construction method of PC box girder bridge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for projecting a corrugated steel sheet web PC box girder bridge, particularly in a form in which a girder is constructed for each block using a mobile work vehicle.
[0002]
[Prior art]
The overhang construction of PC box girder bridge is also called a cantilever type construction method. The bridge body is divided into blocks of several meters in the direction of the bridge axis without using support work, and the construction machine such as a mobile work vehicle from the part near the pier. The girder is built over both sides using
The PC box girder bridge overhang construction is often used because it is a safe and economical construction method because the construction equipment is relatively small relative to the construction scale, regardless of the topography of the construction site.
Conventionally, the corrugated steel web PC box girder bridge constructed by projecting the girders for each block is constructed by using a mobile work vehicle a as shown in FIG. A lower floor plate c and an upper floor plate d were constructed.
This movable work vehicle a is composed of a frame, a work table, and the like, and moves forward on a rail laid on the upper surface of a girder to place concrete on a block-by-block basis. After the construction, proceed with construction in the order of cross beam and upper floor slab d.
That is, the mobile work vehicle a is moved forward and installed so as to correspond to one block e, the corrugated steel sheet web b is installed in the block e, and the formwork of the lower floor slab c is constructed (FIG. 3 ( a)).
Next, the upper floor slab d of this block e and the formwork of a cross beam are constructed | assembled (FIG.3 (b)).
Next, concrete is sequentially cast on the form of the lower floor slab c, the upper floor slab d, and the cross girder form of the block e (FIG. 3C). In addition, a cross beam may be a corrugated steel plate or a flat steel plate.
The mobile work vehicle a is again advanced and installed, and the bridge is constructed by projecting the corrugated steel sheet web b, the lower floor slab c, and the upper floor slab d for each block while repeating the same procedure.
[0003]
[Problems to be solved by the invention]
However, the above-described conventional PC box girder overhang construction method has the following problems.
<I> It is a construction method for each block in one cycle. After curing the concrete of the lower floor slab c for each block, placing the concrete of the cross beam and further curing the concrete of the cross beam Since the concrete of the upper floor slab d is placed, the waiting time for each operation is long and the construction period is long. In addition, when all the lower floor slabs, cross girders, and upper floor slabs are cast in a single concrete placement, the structure of the frame support work for the cross girders and upper floor slabs is particularly complicated. Time and effort is increased.
<B> If the work of the upper floor slab d is started before the work for constructing the form of the lower floor slab c is completely finished, it is dangerous because it is an up / down work.
[0004]
[Object of the present invention]
The present invention has been conceived in view of the above-described conventional problems, and provides a method for extending a PC box girder bridge that is efficient by reducing waiting time and shortening the construction period. Objective.
It is another object of the present invention to provide a PC box girder bridge overhanging method that enables safe work.
The present invention is intended to achieve at least one of the above objects.
[0005]
[Means for Solving the Problems]
In order to achieve the above-described object, the PC box girder bridge overhang construction method of the present invention is a PC box girder bridge overhang construction method constructed by overhanging each block using a mobile work vehicle. The movable work vehicle is moved to the front block, the corrugated steel sheet web of the front block is installed and the form of the lower floor slab is constructed, and simultaneously the form of the upper floor slab of the rear block is constructed, and the front The concrete is characterized in that concrete is placed in the lower floor formwork of the block and concrete is placed in the upper floor formwork of the rear block, and two blocks are constructed simultaneously.
Further, the present invention is a method applicable not only to a corrugated steel web but also to a concrete web.
[0006]
[Embodiments of the Invention]
Embodiments according to the present invention will be described below with reference to the drawings.
[0007]
<A> PC box girder bridge PC box girder bridge 1 is divided into blocks 2 of several meters in the direction of the bridge axis, and this block 2 is projected to both sides using a mobile work vehicle 7 from a portion close to the pier. It is to be constructed.
One block 2 includes a lower floor slab 3 and an upper floor slab 4, a corrugated steel sheet web 5 connecting them, and a cross beam 6. The web may be a concrete web. Further, the cross beam 6 may be a corrugated steel plate or a flat steel plate in the case of concrete.
FIG. 1 is an explanatory view showing a state in which a PC box girder bridge 1 is constructed by a mobile work vehicle 7, in which concrete is placed on a form of a lower floor plate 3 of a front block 2a, and an upper floor plate 4 of a rear block 2b. The state where concrete is placed in the formwork of is shown.
In the present invention, two blocks, the front block 2a and the rear block 2b, are constructed simultaneously.
[0008]
<B> Mobile Work Vehicle The mobile work vehicle 7 includes a support 71 arranged on both sides so as to straddle the PC box girder 1 and a work table 72 having a truss structure connected to the support 71 with a lower support. .
A roller 73 is incorporated in the upper part of the support 71, and this roller 73 rolls on a rail 78 laid on the upper part of the PC box girder bridge 1 so that the entire mobile work vehicle 7 moves forward.
The forward movement can be performed by abutting the rear roller 77 against the lower surface of the PC box girder bridge 1 (lower floor slab 3) and extending a known jack or the like using this as a reaction force.
After the forward movement, the work platform 72 is jacked up by the lifting jack 74 at that position, and the mobile work vehicle 7 is fixed.
A formwork holder 75 is placed on the front portion of the work table 72 so as to be adjustable by an adjustment jack 76, and the formwork of the lower floor slab 3 is constructed by the formwork holder 75.
Furthermore, after placing concrete using the mobile work vehicle 7, prestress is applied, and the mobile work vehicle 7 is sequentially moved forward to project the PC box girder bridge 1 and install it.
In addition, although the mobile work vehicle 7 of an Example has shown the support type, the mobile work vehicle of the format shown in FIG. 3 may be used.
[0009]
Next, a method for extending a PC box girder bridge will be described with reference to FIG.
[0010]
<A> Advancement of mobile work vehicle (FIG. 2 (a))
By extending the jack or the like, the mobile work vehicle 7 is moved forward by one block.
The movable work vehicle 7 before moving forward is a position where the Nth block (front block 2a) and the N-1th block (rear block 2b) immediately before this can be constructed simultaneously. In this state, concrete is simultaneously placed on the lower floor slab 3 of the Nth block and the upper floor slab 4 of the (N-1) th block.
When the mobile work vehicle 7 moves forward by one block, the work table 72 arranged on the lower side of the PC box girder bridge 1 also moves forward by one block. The N + 1th block (new front block 2a) is ready for construction.
[0011]
<B> Installation of corrugated steel web (Fig. 2 (b))
On the work table 72, the corrugated steel web 5 is installed in the (N + 1) th block.
The corrugated steel web 5 is used to connect the lower floor slab 3 and the upper floor slab 4, and a corrugated steel having high strength is used.
In the case of a concrete web, the rebar assembly and formwork assembly steps are performed. In this case, the formwork and rebar assembly of the lower floor slab 3 are performed first.
[0012]
<C> Construction of lower floor formwork and upper floor formwork (Fig. 2 (b))
The formwork of the lower floor slab 3 is constructed on the formwork receiver 75 of the work table 72.
The formwork of the constructed lower floor slab 3 is installed below the corrugated steel web 5 installed in the N + 1th block.
In addition, after constructing the formwork of the lower floor slab 3, the <B> corrugated steel web 5 may be installed. This is the procedure for concrete webs.
Since the workbench 72 is also a position where the Nth block (new rear block 2b) can be constructed, the formwork of the upper floor slab 4 of the Nth block is constructed.
In addition, when it is designed to construct a cross beam 6 (in the case of concrete, a corrugated steel plate or a flat steel plate) in the Nth block, the form of the cross beam 6 prior to the form of the upper floor slab 4 Or assemble a steel plate of cross beams 6.
When it is designed to construct the cross beam 6, there is an advantage that the support work of the upper floor slab 4 can be reduced.
[0013]
<D> Placing concrete (Figure 2 (c))
Concrete is placed on the formwork of the lower floor slab 3 of the (N + 1) th block constructed in <C>, and concrete is placed on the formwork of the upper floor slab 4 of the Nth block at the same time.
In addition, when the concrete cross beam 6 is designed to be constructed in the Nth block, the form of the cross beam 6 is constructed as described in <c> above. It is placed at the same time as the concrete of the upper deck 4.
As a result, concrete is placed on the lower floor slab 3 of the (N + 1) th block, and concrete is placed on the upper floor slab 4 and the cross beam 6 of the Nth block.
That is, concrete is simultaneously placed in two blocks (the front block 2a and the rear block 2b).
In addition, the method of constructing the cross beam 6 simultaneously with the lower floor slab 3 and the corrugated steel web 5 in the front block 2a is also considered.
[0014]
<E> Move the mobile work vehicle forward again (Fig. 2 (c))
When the concrete curing of the upper floor slab 4 of the Nth block is finished and the tension of the PC steel material is finished, a rail 78 is laid on the upper floor slab 4 to prepare the mobile work vehicle 7 for movement.
The mobile work vehicle 7 is again moved forward by one block, and the state shown in FIG.
After the mobile work vehicle 7 is fixed, the work platform 72 performs the construction of the above-described formwork and the concrete placement work.
By repeating this sequentially, two blocks (the front block 2a and the rear block 2b) can be applied simultaneously.
[0015]
In the present invention, compared to the conventional overhang construction in which one block is constructed in one cycle, two blocks 2a and 2b are simultaneously constructed in one cycle, so the construction period is 30 to 40%. The degree can be shortened.
[0016]
[Effect of the present invention]
Since the extension construction method of the PC box girder bridge of the present invention is as described above, the following effects can be obtained.
<B> At the same time as installing the lower floor slab of the front block, construct the upper floor slab of the rear block, cast concrete on the lower floor slab of the front block, and cast concrete on the upper floor slab of the rear block. Since two blocks were constructed at the same time, the waiting time can be reduced and the construction period can be shortened.
<B> When two blocks, the rear block and the front block, are constructed at the same time, a lower floor slab is constructed on the front block and an upper floor slab is constructed on the rear block. Can work safely.
<C> Since not all two blocks are constructed at the same time, the force acting on the mobile work vehicle is reduced, and the weight of the steel material of the mobile work vehicle can be reduced.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a state in which a PC box girder bridge is constructed with a mobile work vehicle.
FIG. 2 is an explanatory view showing a construction procedure of a PC box girder bridge.
FIG. 3 is an explanatory view showing a construction procedure of a conventional PC box girder bridge.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... PC box girder bridge 2 ... Block 2a ... Front block 2b ... Back block 3 ... Lower floor slab 4 ... Upper floor slab 5 ... Corrugated steel web 6 ... Cross girder 7 ... Mobile work vehicle 72 ... Work bench

Claims (1)

In the extension construction method of PC box girder bridge constructed by overhanging the girder for each block using a mobile work vehicle,
Moving the mobile work vehicle to the front block;
Constructing the form of the corrugated steel sheet web of the front block and the form of the lower floor slab, and simultaneously constructing the form of the upper floor slab of the rear block,
Placing concrete in the lower floor formwork of the front block and placing concrete in the upper floor formwork of the rear block;
It is characterized by constructing two blocks at the same time.
Overhang construction method of PC box girder bridge.

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