JPH01290806A - Construction method for bridge - Google Patents

Abstract

PURPOSE:To enable construction to be executed safely and economically without adverse effect from ground side by casting a bridge pier in-place by making use of an inverse triangular supporting bracket wherein weight in the vertical direction is supported by the basement of the bridge pier, and horizontal displacement is restrained by the bridge pier. CONSTITUTION:The supporting bracket 1 of a truss structure made of steel members composed of a vertical column 2, a support section 3, an oblique column 4 and truss members 5, is rested on the footing 8 of a bridge pier 7. Then, the vertical column 2 is fixed onto the bridge pier 7 with connecting members 10 such as PC steel bars and the like. Following which, a frame 6 is assembled using the top of the support section 3 as a work stand. After the frame has been assembled, concrete is placed in the frame so that an in- place girder 11 is constructed integrally with block bodies 9b, 9c, 9d and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method of constructing bridges such as continuous girders, Gelper girders, or arch bridges.

<Conventional technology> When the girder is high or the water depth of the river is deep, the cantilever construction method is used, in which the supporting members are successively extended from the top of the pier in a cantilever manner.

Furthermore, for the purpose of shortening the construction period, it is known to use, in addition to the cantilever construction method, a construction method in which construction is performed by casting in place in an area that can be supported from the ground side.

By the way, when pouring in place, shoring has traditionally been used.

This shoring is assembled by arranging columns made of steel frames or the like in the vertical direction at appropriate intervals and connecting a large number of bracing members between these columns.

<Problems to be solved by the present invention> The conventional shoring technology described above has the following problems.

(b) Foundation work is required on the ground side where the shoring will be placed.

However, if the planned site for foundation work is steep, sloped, or weak, the countermeasure work will be large-scale and difficult.

(b) There remains a risk that the shoring will collapse due to uneven settlement;
There is a problem in terms of safety.

(c) The higher the height of the shoring, the worse the stability of the shoring becomes, and countermeasures are required.

(d) In order to restrain displacement in the horizontal direction, it is necessary to install wire robes, etc. on the shoring, and it takes time to attach and detach them.

OBJECTS OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide the following bridge construction method.

(a) A bridge construction method that can be constructed without being affected by the ground side.

(b) A method of constructing bridges that eliminates the risk of supporting supports collapsing.

(c) A bridge construction method that enables economical construction.

Means for Solving the Problems> The present invention is a method of constructing a TF4 bridge by casting in place, in which the footings of the piers are used, and the lower ends of the brackets assembled in the shape of an inverted triangular prism are attached to the footings. At the same time, the bracket is fixed to the circumferential surface of the pier using PC steel rods, etc., and the vertical load is supported by the footing.
The bridge is constructed by casting in place with horizontal displacement restrained by the piers.

Configuration of the Present Invention> Next, an embodiment of the present invention will be described with reference to the drawings.

(B) Support bracket (Figures 1 and 2) The support bracket 1 basically consists of a plurality of vertical supports 2 arranged in the vertical direction.
and a support part 3 extending in a right angle direction at the upper part of the verticality 2,
A diagonal strut 4 that diagonally connects between the lower part of the vertical strut 2 and the free end of the support part 3, and a truss member 5 that connects each vertical strut 2, each diagonal strut 4, and the compatible columns 2.4. It is a truss structure consisting of, for example, a steel material or the like.

The protruding length of the support portion 3 varies depending on the length of the bridge to be constructed, but is set to at least a length that can support the formwork 6 in a stable state.

The total length of the vertical support 2 is formed to be equal to the distance from the upper surface of the footing 8 of the pier 7 to the formwork 6.

The lower end of the diagonal support 4 is formed obliquely so as to be in surface contact with the upper surface of the footing 8.

Further, the support bracket 1 may be manufactured by welding each member, but if it is constructed by bolting, the support bracket 1
can be easily assembled and disassembled.

Next, we will explain the bridge construction method.

(a) Bridge extension work (Figure 3) Bridge blocks 9b and 9c are placed on both sides of the head 9a of the pier 9.
, 9d... are connected in sequence and extended in the horizontal direction.

This overhanging work is performed using, for example, a known tab spatula.

(b) Casting in place work (Fig. 1.2) After extending the block bodies 9b, 9c, 9d, etc. to a predetermined length, the area from the end to the adjacent pier 7 (between the side diameters)
Then, pour concrete according to the following steps.

[Attachment of Support Bracket] The support bracket 1 is placed on the footing 8 of the pier 7.

In this case, the lower ends of the vertical strut 2 and diagonal strut 4 constituting the support bracket 1 are placed on the footing 8, and the side surface of the vertical strut 2 is brought into contact with the circumferential surface of the pier 7.

Then, using the connecting material 10 such as a PC steel rod, the vertical support 2
is fixed to the pier 7.

Note that in order to pass the connecting member 10 through the pier 7, it is necessary to make a hole in the pier 7 in advance.

In the present invention, the work of attaching the support bracket 1 can be started without waiting for the completion of the work of extending the block bodies 9b, 9c, 9d, . . . .

Also, if the top surface of the footing 8 is sloped, a dedicated stand with a horizontal top surface is added on top of the footing 8,
The support bracket 1 is placed on this dedicated stand.

[Assembling the formwork] Next, the formwork 6 is assembled using known temporary members using the support portion 3 of the support bracket 1 as a workbench.

[Placement of Concrete] After completing the assembly of the formwork 6, concrete is poured into the formwork 6 to construct the column and beam 11 integrated with the block bodies 9b, 9c, 9d, . . . .

[Curing, demolding] During the curing period, the weight of the column beams 11, formwork 6, etc. is supported by the footings 8 of the piers 7 by the support brackets 1.

In addition, the horizontal displacement acting on the support bracket 1 is
It is restrained by the connecting member 10 connected to.

After a predetermined period of time has elapsed, the formwork 6 is dismantled and the support bracket 1 is removed.

Other Examples> In the above example, a case was explained in which the support bracket 1 was attached to one side of the pier 7 and the column beam 11 was constructed.
It is also possible to construct cast-in-place columns and beams 11 on both sides of the pier 7 by reusing the support brackets 1.

<Effects of the Present Invention> Since the present invention is as described above, the following effects can be obtained.

(b) Only the top surface of the foundation of the pier can support the load of cast-in-place concrete.

Therefore, not only does the conventional foundation work on the ground side become unnecessary, but the bridge can be constructed without being influenced by the shape or geology of the area below it.

(b) Since the load of cast-in-place concrete is supported by the foundations of the piers, there is no need to worry about uneven settlement.

(c) Previously, shoring work was carried out after the bridge overhang work was completed.

On the other hand, the present invention is advantageous in terms of process since it is possible to assemble the formwork for site pouring in parallel with the bridge overhanging work.

2) Since the support bracket is placed on the pier and fixed integrally, displacement in the horizontal and vertical directions can be reliably restrained without installing sex robes as in the past.

Therefore, work safety is significantly improved.

(E) The amount of steel used to construct the support bracket can be significantly reduced compared to conventional shoring.

Furthermore, the time required for disassembling and assembling the support bracket can be reduced by about 40% compared to the conventional method.

(f) The support bracket can be easily repurposed.

[Brief explanation of the drawing]

Figure 1: An explanatory diagram of the bridge construction method according to the present invention, when the bridge is actually constructed using support brackets.

Claims (1)

[Claims] (1) In a bridge construction method in which a bridge is constructed by casting in place between the end of a bridge constructed by cantilevering a block body from the head of the pier and a separate pier, on the foundation of the pier. At the same time, the lower end of the support bracket of the truss structure assembled in the shape of an inverted triangular prism that becomes wider toward the top is placed, and the support bracket is integrally fixed to the circumferential surface of the pier using connecting materials, and the vertical load is A bridge construction method in which the bridge is cast in place with the bridge supported by the pier foundation and horizontal displacement restrained by the pier.