JPH09250110A - Construction method of arch concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote economic efficiency construction accuracy of arch concrete form construction. SOLUTION: The lower ends of semi-arch-shaped trusses 3a and 3b having height dividing a span of an arch concrete C into approximately two parts are connected to leg structures 1 and 1, the top of one semi-arch-shaped truss 3a connected to one side 13 of the upper end of a post 5 having a height adjusting device 10, and a form timbering A mounting the top of the other semi-arch-shaped truss 3b on the other side of the upper end of the same post 5 thereon in a slidable manner is used to construct the arch concrete C. When the post 5 is settled in case of placing concrete, the height of the post 5 is restored to an original state, the occurrence of excessive stress in the concrete casted to solidify is prevented and, at the same time, construction accuracy of the arch concrete C is matained in a good state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing arch concrete using a form supporting method using a combination of arch trusses and columns.

[0002]

2. Description of the Related Art For formwork support applied to the construction of arch concrete in arch bridges, for example, an arch truss is to be installed between abutments (piers) as described in Japanese Patent Publication No. 3-64001. Construction work has come to be carried out, and workability and economic efficiency have been significantly improved.

However, even if the above-mentioned form supporting work is applied to a long span as it is, it will become a large-scale structure and its advantages will be lost. Therefore, for example, Japanese Patent Laid-Open No. 4-194169 and Japanese Patent Laid-Open No. 5-194169
Form support by combining divided trusses and struts as described in Japanese Patent No. 17913 has been developed and applied to the construction of long spans and flat arch concrete.

[0004]

By the way, in the above-mentioned form supporting work, when the concrete is placed, the props may sink a little, and in that case, an excessive load is applied to the truss. It has a structure that can cope with the sinking of columns.

However, since the ground is inherently uncertain, the columns may sink more than expected. In such a case, in the above-mentioned form supporting work, a structurally difficult problem arises in order to cope with a large sinking of the column.

On the other hand, the construction of arch concrete is carried out by placing concrete on the formwork installed on the formwork support, but this concrete cannot physically place the span length at the same time. Therefore, we set the section of the range where concrete can be poured at one time and divide it. Considering the workability, it is a good idea to carry out this divided driving in order, starting from both lower ends of the formwork upwards.

In such a case, the load of the vertical load on the support column will gradually increase as the concrete pouring progresses upward. At that time, if the pillars may sink, the form support will be deformed and settled as a whole, causing mold separation from the hardened concrete in the section that was placed earlier, Excessive stress will be applied to the concrete, and there will be inconvenience such as a step between the concrete and the next concrete to be placed.

In order to prevent this, for example, Japanese Patent Application Laid-Open No. Hei 5
-280013, it is necessary to take special measures for strengthening the connection between the concrete cast in the lower end section and the leg structure or the concrete in each section, and the construction by this This will increase the trouble and expense. Further, if the amount of deformation and settling of the formwork support work is large, there is a problem that the arch concrete itself cannot obtain the shape and strength as designed.

Further, in the form supporting work disclosed in the above-mentioned Japanese Patent Laid-Open No. 5-179913, a pair of a semi-arched truss and a composite body of columns is completely separated, and a pair of columns at the center of the arch. Is independent of each other, and is characterized by no horizontal connections or braces between them. Therefore, while the pair of columns are in close proximity, they cannot jointly resist the load generated by concrete pouring, and each column must stand against the load independently, so that the columns with large cross section Material is required, and the cost increases accordingly. It is natural that a technology for constructing the pair of pillars in the close position as an integral pillar to be inexpensive is required.

The present invention has been made in order to solve various problems in the above-mentioned form supporting work, and the tops of the arch-shaped trusses divided into two are supported by a single strut, and In order to increase the reliability of the results of structural analysis, a formwork supporting structure that allows both arch-shaped trusses to slide relative to each other in the span direction was used. Adjusting the height of the columns to restore the height of the support points of the truss to the original state, suppressing the settling and deformation of the formwork support work, and the formwork of the formwork and the cast concrete. It aims to prevent separation and to prevent excessive stress from occurring in the concrete, to improve the construction accuracy of arch concrete, and to facilitate and improve the efficiency of concrete placing work.

[0011]

The construction of the present invention for achieving the above object will be described with reference to the drawings corresponding to the embodiments. A pair of semi-arched trusses 3a and 3b, each of which has a length substantially divided into two, are connected to the leg structures 1 and 1 at their lower ends, and a single column is erected on the ground B so that the height of the truss can be adjusted. 5, the top end portion of one semi-arched truss 3a is connected and supported 13, and the other semi-arched truss 3b is connected.
Using the frame support A formed by supporting and mounting the top end of the frame 14 slidably in the span direction, arch concrete C
When the pillar 5 is submerged due to the pouring of concrete, etc., the height of the pillar 5 is adjusted to correct the subsidence.

Further, the construction method of claim 2 is such that a plurality of trusses 4a and 4b are connected to each other, and a pair of half arch trusses having a length obtained by substantially dividing the span of the arch concrete C into two are provided.
a, 3b are connected to the leg structures 1, 1 at their lower ends, respectively, and a single strut 5 is installed on the ground B so that the height of the semi-arched truss 3a can be adjusted. Combine 1
3, support, the top end of the other semi-arched truss 3b,
Formwork support A that supports and supports the platform 14 slidably in the span direction, and also supports the joints 17 of the respective trusses by the columns 6 that are erected on the ground B and whose height is adjustable. When constructing the arch concrete C using, the subsidence of the above-mentioned struts 5 and 6 due to the placing of concrete, etc. occurs, the height of the submerged struts 5 and 6 is adjusted to correct the subsidence. It is characterized by performing.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention, and FIG. 2 shows a second embodiment.

First, the first embodiment will be described. In FIG. 1, 1, 1 are leg structures such as abutments, piers, etc., which are constructed at a predetermined interval prior to placing the arch concrete C, and A is a form supporter used in the present invention (hereinafter referred to as "framework support"). An arch-shaped formwork 2 is installed on the upper surface of the supporting structure.

The support A is a pair of semi-arched trusses 3a and 3b each having a length obtained by dividing the span of the arch concrete C into about two, and the ground B at the center between the leg structures 1 and 1. It is composed of a pillar 5 standing upright.

As shown in FIGS. 1 to 3, the support column 5 includes a plurality of horizontal rods 8 and 8 and diagonal members 9, which are column members 7 and 7 arranged in parallel in the span direction of the arch concrete C at a required interval. 9
It is formed by connecting with. With this structure,
Posts with high strength and rigidity can be formed using inexpensive ready-made materials. The pillar 5 is not limited to such a structure,
For example, H-shaped steel or the like having a relatively high height (width in the span direction of arch concrete C) may be used as a single body or a composite body. A bracket 11 is provided on one side of the upper end of the column 5, and a pedestal 12 is provided on the other side of the column 5 so as to project upward.
A height adjusting device 10 such as a hydraulic jack is provided so that the height of the column 5 can be adjusted, and the support column 5 is erected on the ground B via the height adjusting device 10.

The pair of semi-arched trusses 3a and 3b
Is connected to the leg structure 1 by a pin or the like at the lower end.
The top of one of the semi-arched trusses 3a is connected to a bracket 11 projecting on the upper end of the pillar 5 by a pin or the like 13
Then, the top of the other semi-arched truss 3b is placed 14 on the pedestal 12 slidably in the span direction of the arch concrete C.

The supporting work A having the above structure is provided in a plurality of rows at a predetermined interval in the depth direction of the arch concrete C to be constructed, and is connected to each other by using connecting rods (not shown).
Further, the formwork 2 is attached via the support tools 16, 16 such as bolts and flaps that are attached to the beam structure of the above-mentioned support and support A installed. Then, concrete C is placed on the formwork 2.

The concrete is poured by setting a section in the span direction of the arch concrete C that can be poured once. In the present invention, first, the concrete in the lowermost section of the arch concrete C is connected to the leg structure 1 to be placed, and thereafter, the concrete is successively placed upward. At that time, the placing load of the concrete is the semi-arched truss 3
When the semi-arched trusses 3a and 3b are flexed as a result, the tops of the semi-arched trusses 3b are supported by the pillars 5a and 3b.
It is possible to prevent the generation of excessive stress by sliding in the span direction in accordance with the bending.

In addition, when the condition of the ground B is bad in the process of staking the arch concrete C, the pillar 5
Will sink. In such a case, the semi-arch trusses 3a and 3b are already hardened because the tops of the semi-arch trusses 3a and 3b are lowered and the half arch trusses 3a and 3b are inclined downward with the joint portion 15 as the center.
There will be mold release from the concrete in the lowest section that was initially cast or the concrete that is being spliced to it, and these concretes must be cantilevered to support their own weight. May occur and the concrete in that part may be destroyed.

When the concrete is to be spliced in a state where the mold is separated, the concrete that has been placed,
Not only will the step portion of the splice be formed with the already hardened concrete, but the entire arch concrete C will also be flattened, and the shape and yield strength of the entire arch concrete will deviate from the design values. It will also be done.

In the present invention, as described above, when the pillar 5 sinks when pouring concrete, the height adjusting device 10 is extended in accordance with the sinking amount of the pillar 5, and the semi-arched truss 3a. , 5 b, which is combined with the tops of 3b and placed 13 and 14
The upper end position (height position) of is corrected to the original state before subsidence. Since the subsidence of the pillar 5 may occur each time due to the stepwise pouring of concrete, the subsidence correction of the pillar 5 may be performed in accordance with the required amount each time.

Next, a second embodiment will be described. This embodiment uses a supporting structure A formed so as to be suitable for construction of arch concrete having a long span. That is, the semi-arched trusses 3a and 3b that form the support A
Of the divided trusses 4a,
4b is connected 17 by a pin or the like to form a semi-arched shape.
Then, the connecting portion 17 is coupled and supported to the upper end portion of the pillar 6 provided with the height adjusting device 10 standing on the ground B, like the pillar 5 above. In addition, the lower end of the split truss 4a is connected to the leg structure 1, and the top of the split truss 4b is the pillar 5.
It is connected to the upper end of the and mounted 13 and 14.

Also in the case of this embodiment, when the columns 5, 6 sink due to the pouring of concrete, the columns 5, 5
It goes without saying that the height of each 6 is adjusted in accordance with the amount of subsidence and the subsidence is corrected.

The number of joints of the divided trusses 4a and 4b is not limited to two, but can be increased if necessary, and the number of columns supporting the connecting portions of the divided trusses can be increased accordingly. become.

[0026]

As described above, according to the present invention,
The arch-shaped frame supporting work to be installed between the leg structures is composed of a pair of half-arched trusses that are divided into two, and one of them is connected to the leg structure and the post whose height is adjustable. , Since the other is slidably placed and erected independently, each semi-arched truss can be calculated as a static beam, and therefore
The structural analysis is extremely reliable, and since the pair of semi-arched trusses are related to each other through a single strut, the formwork support is simplified and the structure is provided as an inexpensive structure. In particular, arch concrete with a large span can be economically constructed.

Further, when the pillar supporting the semi-arched truss is sunk by pouring concrete or the like, the height of the pillar is adjusted to restore the height of the top support point of the semi-arched truss to the original state. Since it is returned, it is possible to prevent the mold from separating from the concrete that was placed in advance, and to prevent excessive stress from occurring in the concrete, thus simplifying construction and improving efficiency, and at the same time designing the shape. Highly accurate and accurate arch concrete construction is possible.

[Brief description of drawings]

FIG. 1 is a schematic front view showing an embodiment of the present invention.

FIG. 2 is a schematic front view showing another embodiment.

FIG. 3 is an enlarged front view showing a main part of a column.

[Explanation of symbols]

 A formwork support B ground C arch concrete 1 leg structure 2 formwork 3a, 3b semi-arched truss 4a, 4b split truss 5,6 prop 10 height adjuster 11 bracket 12 cradle 13 joint 14 mounting Part 15 Joining part 16 Supporting part 17 Connecting part

Claims (2)

[Claims] 1. A pair of semi-arched trusses each having a length obtained by substantially dividing an arch concrete span into two, each lower end of which is connected to a leg structure, and which is vertically erected on the ground so that its height can be adjusted. Form support that is formed by connecting the top end of one semi-arched truss to one column and supporting it, and by mounting and supporting the top end of the other semi-arched truss slidably in the span direction. When the arch concrete is constructed by using, when the subsidence of the pillar due to the placing of concrete occurs, the height of the pillar is adjusted, and the subsidence is corrected, the arch. Concrete construction method. 2. A pair of semi-arch trusses each having a length obtained by joining a plurality of trusses to divide the span of arch concrete into two parts, each lower end portion of which is joined to a leg structure, and a height of the ground. The top end of one semi-arched truss is connected and supported by a single strut that is adjustable, and the top end of the other semi-arched truss is mounted and supported slidably in the span direction. In addition, when constructing arch concrete by using formwork supports formed by supporting the joints of each truss with the stanchions that are erected on the ground so that the height can be adjusted freely, when placing concrete, etc. A method for constructing arch concrete, characterized in that, when subsidence of the above-mentioned pillar occurs, the height of the submerged pillar is adjusted to correct the subsidence.