JPH0978531A - Work execution method for arch bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply form an arch rib during the arch bridge work execution process. SOLUTION: A scaffold 5 is assembled in the span of a lower structure 3 constituted of abutments and bridge piers 2, a balloon type formwork 6 is carried-in onto the scaffold 5, and compressed air is filled to inflate it into a semicircular shape. PC steel products 8, 8... are arranged perpendicularly to the bridge axis along the peripheral face of the balloon type formwork 6, and a welded wire mesh 9 is installed. Concrete 10 is placed on the peripheral face of the balloon type formwork 6. When the concrete 10 reaches the strength of about 300kgf/cm<2> , it stretches the PC steel products 8, 8... to introduce prestress. After the concrete 10 is hardened, waterproof coating is applied on its outer peripheral face, and an arch rib 4 is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arch bridge construction method, and more particularly to an arch bridge construction method that simplifies arch rib formation by using a balloon type mold.

[0002]

2. Description of the Related Art In a conventional arch bridge, an H-shaped steel semicircular support structure is assembled between piers, a steel formwork is arranged on the support structure to assemble steel bars, and then concrete is struck. Installed to form arch ribs. Then, a side wall is provided on the side edge of the arch rib to construct a bridge.

[0003]

Since the arch bridge can absorb the member displacement due to the temperature change and the like by the expansion and contraction of the arch rib, it is not necessary to provide an expansion joint in the middle of the bridge unlike the girder bridge. In addition, it has good running performance when used for passing vehicles, and is also excellent in scenery.

However, since it is necessary to accurately assemble the semicircular support work for forming the arch rib, the construction is more difficult and the construction cost is higher than that of the girder bridge. For long-axis arch bridges with a large number of spans, one support structure may be moved along the rail to form arch ribs for each span for efficiency, but the rail and the pier on which the rail is mounted It becomes necessary to attach a support, and the movement of the support work involves the risk of falling due to wind or the like.

Therefore, there arises a technical problem to be solved in order to efficiently form the arch bridge by making it possible to easily form the arch rib, and the present invention intends to solve the problem. To aim.

[0006]

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-mentioned problems, in which an airtight and flexible balloon mold is carried into a space on the lower structure. hand,
By filling the balloon mold with air to expand the arch rib inner wall surface shape and increasing the internal pressure to give the balloon mold a predetermined strength, the balloon mold is shaped along the peripheral surface thereof. An arch bridge construction method for placing concrete to form arch ribs.

Here, the internal pressure applied to the balloon mold during expansion of the balloon mold resists the weight of the welded wire mesh for arch ribs or concrete for arch ribs laid or cast on the balloon mold. It is set to the extent that it can be obtained.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
4 to 4 will be described in detail. Fig. 1 shows an intermediate stage of construction of an arch bridge with 5 spans. A substructure 3 is constructed by abutments 1, 1 and piers 2, 2 ...
The arch ribs 4 and 4 for the span have been completed, and the arch rib 4 at the center is now being formed. Thus, a scaffold 5 is assembled on the upper surface of the lower structure 3 in the center span, and a balloon mold 6 is mounted on the scaffold 5.

The balloon mold 6 is made of an airtight and flexible material such as rubber or resin, and is carried in a deflated state and then filled with air to form a semi-columnar shape. Expands to. At this time, as shown in FIG. 2, by arranging arch-shaped strips 7, 7 ... in parallel above the balloon type mold 6, the balloon type mold 6 forms an arch rib inner wall surface shape. In addition, the internal pressure is sufficiently increased to withstand the weight of welded wire netting and concrete described later.

As shown in FIG. 3, PC steel materials 8, 8 ... Are arranged along the peripheral surface of the balloon mold 6 so as to be orthogonal to the bridge axis, and a welding wire net 9 is laid. After that, the concrete 10 is wound on the peripheral surface of the balloon type mold 6 with a spraying concrete machine until the thickness becomes about 30 cm.
Spray in layers. Concrete 10 is about 300kg
When the strength of f / cm ² is reached, the PC steel materials 8, 8 ... Are pulled to introduce prestress. After the concrete 10 is hardened, a waterproof coating is applied to its outer peripheral surface. Thus, the arch rib 4 having the center span is completed.

Thereafter, the compressed air in the balloon mold 6 is extracted and contracted. Then, the scaffold 5 is detached from the center span and is constructed on the right adjacent span, and again in the same manner as described above using the balloon type mold 6, an arch rib is provided on the center right adjacent span. Form. By diverting one balloon mold 6 in this way, arch ribs 4, 4, ... Of the same shape are formed over the entire diameter.

After completion of the arch ribs 4, 4, ..., As shown in FIG. 4, side walls 11, 11 and wall rails 12, 12 are placed on both sides of the arch rib 4, and after filling the filling soil 13, the road surface The precast plate 14 is laid. Thus, the construction of the arch bridge is completed.

The present invention can be modified in various ways without departing from the spirit of the present invention, and it goes without saying that the present invention covers the modified products.

[0014]

As described above, the present invention is configured to use the balloon type mold as the arch rib mold. Therefore, it is only necessary to fill the balloon mold with compressed air, and it is not necessary to assemble the supporting structure into a semicircular shape as in the conventional case, so that the arch rib construction process is extremely simplified.
Further, when one balloon type frame is diverted to a plurality of diameters, it is sufficient to shrink the balloon type frame after forming one arch rib and convey it to the next radius. It is simple, quick, and safe, as compared with a means for moving it.

Further, if a plurality of balloon ribs are used to form a plurality of arch ribs at the same time, the arch bridge can be constructed much more easily and quickly than the conventional H-shaped steel support work.
Thus, the difficulty of arch bridge construction is solved, and the girder bridge can be sufficiently countered in terms of construction cost.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention at an intermediate stage of constructing an arch bridge having 5 spans.

FIG. 2 is a perspective view showing a state where the balloon mold is inflated.

FIG. 3 is a side view of an essential part showing a stage in which an arch rib having a center span is formed in FIG. 1;

FIG. 4 is an end view taken along the line AA of FIG. 1 when the arch bridge is completed.

[Explanation of symbols]

 1 Abutment 2 Bridge pier 3 Substructure 4 Arch rib 5 Scaffold 6 Balloon formwork 7 Band material 8 PC steel material 9 Welded wire mesh 10 Concrete 11 Sidewall 12 Wall balustrade 13 Filled soil 14 Precast version

Claims (1)

[Claims] 1. An airtight and flexible balloon mold is carried into a space on a lower structure, and the balloon mold is filled with air to expand into an arch rib inner wall surface shape. And, an arch bridge construction method characterized by forming an arch rib by placing concrete along the peripheral surface of the balloon mold after increasing the internal pressure to give a predetermined strength to the balloon mold. .