JPH05280013A - Process for forming arch concrete with use of arch-like form timberwork - Google Patents

Abstract

PURPOSE:To enhance the earthquake resistance during placing of concrete for forming arch concrete using an arch-like form timberwork in combination of a truss and a support column. CONSTITUTION:A plurality of trusses 3 are joined together in an arch-like shape, and timberwork A which supports the joint parts of the trusses 3, 3 by means of support columns, is laid between lef part structures 1, 1. Before concrete is placed over the trusses, earthquake structures D are projected from the leg part structures 1. Then, concrete is placed, in sections of arch concrete, at first, being joined to the front end parts of the earthquake structures D, and is then placed successively in desired sections of the arch concrete. Then, concrete is placed between the concrete which has been at first placed in a section b1 and the leg part concrete structures 1 so as to form the entire arch concrete C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction method for performing arch concrete construction on arch bridges and the like by using arch form supports.

[0002]

2. Description of the Related Art Conventionally, there are various methods for constructing arch concrete (arch ribs) for arch bridges, etc., such as cantilever projecting method, center form supporting method, and strut type supporting method. Construction by arch-shaped frame support work developed by the workers has become popular. In particular, for the construction of long spans and flat arch concrete, Japanese Patent Application Laid-Open No. 2-2
The effect by the support work described in No. 40310 and No. 240311 is more effective.

As shown in FIGS. 1 and 2, this support work is
As shown in FIG. 3, the depth of the arch concrete C to be constructed is as shown in FIG. Parallel to each other, and are connected to each other by connecting members 8 and 8 and diagonal members 9 and 9.
In this structure, the connecting portions of the divided trusses 3 and 3 are supported by the pillars 6 standing on the ground B as well as being coupled to the first and the fifth.

Therefore, the construction of arch concrete C is
This is done by placing concrete on the formwork 7 installed on the support A. However, since it is physically impossible to place the entire span of this concrete at the same time, as shown in FIG. , It is necessary to set the sections C _{1 to} C ₅ within the range where concrete can be poured at one time and to place them in a divided manner. The first problem is how to order these divided sections. ..

If the construction order of the arched concrete is determined only by considering the workability, it is decided that the arching concrete should be sequentially driven upward from both lower portions. That is, in FIG. 1, first, C ₅ , C _{5 and} then C ₁ , C ₁ and C ₂ ,
The C _2, C _3, C ₃ last C ₄ is the order of pouring.

However, the deformation of the support work due to the concrete pouring of the other section after the hardening of the C ₅ and C ₅ concrete at the first time of placement causes the moments to the already hardened bottom concretes C ₅ and C ₅ one after another. And when all the concrete has been cast, a very large moment may occur and the concrete may be destroyed. Therefore, in general, the bottom concrete must be the final casting. In other words, the pouring of the first is not to be started out by skipping the C _5, C _5. After that, it may not always be possible to drive upward until the end, and a moment exceeding the allowable value may occur in the hardened concrete near the upper part of the column.

Therefore, the area near the upper part of the column may also be the last section to be hit. The pouring order when is Da設and _{C 1, C 1, C 2} , C 2, C 3, C 3 as shown in FIG. 2, then jump strained the C _4, finally stuffed C ₄ It ends by hitting C ₅ and C ₅ .

[0008]

As described above, in pouring arch concrete, not only the concrete pouring for each section is repeated, but also the pouring is done in a scattered manner. Therefore, the partition formwork must be installed and removed each time. From what you need to do
The concrete pouring period will be long. In such a case, in Japan, where there are many earthquakes, it is expected that the supports will be significantly deformed or destroyed during the construction.

It is known that the seismic load at which the arch support A is dangerous is a horizontal load in the width direction of the support A (direction perpendicular to the bridge axis), and other loads are not a problem.
The horizontal load due to an earthquake depends on the seismic coefficient (0, 1
It is a value obtained by multiplying 0, 2), but if concrete that is in a struck state is placed on support work A, all horizontal loads due to the earthquake of that concrete must be supported by support work. .

Even if a small horizontal load is supported by the supporting work, it does not cost much, but at the maximum load, the supporting work requires a very expensive cost to reinforce the supporting work. The maximum horizontal force is when all of the concrete except for the bottom ends C ₅ and C ₅ of both arches, which is the final placement, is finished. At this time, it is assumed that a horizontal load for most of the total weight of arch concrete will be applied in the width direction of the support work, and it will be very expensive to reinforce the support work to withstand this load. End up. Also, when the upper part of the support post is post-cast, similarly expensive reinforcement is required.

For this reason, in order to suppress the generation of moments, it has been required to provide an inexpensive earthquake countermeasure for arch support work in the case of jumping.

The present invention has been made in view of the above circumstances, and has a problem based on the idea that the horizontal load in the width direction due to the earthquake of concrete is not received by the support work but is received by the hardened concrete itself. It is intended to solve the problem.

[0013]

According to the present invention, arch concrete is continuously cast upward from both lowermost end portions C ₅ and C ₅ , and when they are hardened, the arch concrete becomes a leg structure 1. Since it constitutes a strong cantilever beam that is completely connected to 1, the horizontal load in the width direction due to the earthquake of hardened concrete can be sufficiently endured by this cantilever beam. In the present invention, when the lowermost end is skipped and concrete is launched from C ₁ and C ₁ above it, the lowermost end C ₅ and C ₅
A structure with the required bearing strength against earthquakes is arranged in a section as a part of the concrete cantilever beam substitute member, and the discontinuous part that is the final placement is filled to form a continuous cantilever beam. This cantilever is used to support the load, and the load applied to the support work is to be significantly reduced. Further, the same means is used to solve the last section of the upper part of the column.

That is, in the construction method of claim 1, an arch-shaped structure a is formed by connecting divided trusses having lengths obtained by appropriately dividing the span of the arch concrete C to 3, 3 to each other 4 and 4.
Are connected in parallel to each other, the lower ends of the arch-shaped structures a are connected to the leg structures 1, 1 and 5, and the connecting portions 4 and 4 of the divided trusses 3 and 3 are erected on the ground B. Stanchions 6,
The arch-shaped frame support A is erected by being supported by 6, and the leg structure 1 is provided with a seismic structure D that opposes the horizontal external force of the arch concrete C in the width direction. Protruding on both lower ends of the arch concrete C
The initial placement of the above is performed in the required length sections C ₁ and C ₁ on the divided truss 3 at the end of the support A by connecting it with the tip of the seismic resistant structure D, and then sequentially upward. To pour concrete, and at the end, pour concrete into C ₅ between the concrete in the originally placed section C ₁ and the leg structure 1, and bury the earthquake-resistant structure D in the concrete. It is characterized by.

Further, in the construction method of claim 2, the arched structure a is formed by connecting the divided trusses 3 and 3 of the length obtained by appropriately dividing the span of the arch concrete C to each other by connecting them 4 and 4.
Are connected in parallel to each other, the lower ends of the arch-shaped structures a are connected to the leg structures 1, 1 and 5, and the connecting portions 4 and 4 of the divided trusses 3 and 3 are erected on the ground B. Stanchions 6,
The arch-shaped frame support A is erected by being supported by 6, and the leg structure 1 is provided with a seismic structure D that opposes the horizontal external force of the arch concrete C in the width direction. Protruding on both lower ends of the arch concrete C
The initial pouring of the concrete is carried out at the required length sections C ₁ and C ₁ on the divided truss 3 at the end of the support work A by connecting it to the tip of the seismic resistant structure D, and At the tip of C _{1 of the}
Projected over the pillar 6 close to C ₁ , and then in the required length section C ₂ on the split truss 3 connected to the split truss 3,
Concrete C ₃ is placed in connection with the tip of the seismic resistant structure D, and then concrete is successively spliced upward, and at the end, concrete and leg structure 1 in the originally placed section C ₁ are placed. The concrete is characterized in that concrete is poured between C ₅ and C ₅ and between the section concretes that are subsequently placed C ₄ and the seismic structure D is embedded in the concrete.

[0016]

The construction method of the present invention is configured as described above, and the concrete in the cast section is integrally connected to the earthquake-resistant structure, whereby the cast and hardened concrete portion is Even during construction, the leg structure and the structure that is strongly connected in the width direction of the arch will always be maintained, so even when a large horizontal force due to an earthquake is applied during the construction of arch concrete, Since the hardened arch concrete and the earthquake-resistant structure are integrated and resist the horizontal force, it contributes to the deformation and destruction prevention of the arch concrete and the supporting work.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. Fig. 1 shows a state in which arch concrete is installed by using arch-shaped frame supports. The arch-shaped form is mounted on the leg structures 1, 1 facing each other such as abutments and mounting bases 2, 2. The lower end of a supporting work (hereinafter referred to as a supporting work) A is framed by connecting pins 5 and 5, and a frame 7 is installed on the upper surface of the supporting work A, on which an arch concrete C is formed.

The supporting work A has a required number (4 pieces) of divided trusses 3 and 3 having a length obtained by appropriately dividing the span of the arch concrete C (4 divisions in the embodiment of FIG. 1) at each end with pins. As shown in FIG. 3, a plurality of arch-shaped structures formed by combining 4 are arranged side by side and connected by connecting members 8 and 8 and diagonal members 9 and 9. Then, the lower end of each arch-shaped structure a is pin-connected to the mounting bases 2 and 2, and the connecting portions formed by the pin-connections 4 and 4 of the divided trusses 3 and 3 are supported by the columns 6 and 6 standing on the ground B. It has a structure.

Further, each leg structure 1 is provided with a seismic structure D as shown in FIGS. 4 and 5. In this seismic structure D, load bearing rods 14, 14 such as H-shaped steel are arranged side by side in the width direction of arch concrete C at intervals, and the ends thereof are joined by connecting rods 15 and by braces 16, 16. Then, the base end of each load bearing rod 14 is embedded in the concrete when the leg structure 1 is constructed, and the seismic resistant structure D is provided so as to project above the lower end of the support A. The connecting rod 15 is provided with a large number of anchor bolts 17, 17 embedded in the concrete of the arch concrete C that is initially placed so as to be integrally connected.

After the frame of the supporting work A, the form 7
After the required reinforcements such as reinforcing bars 18 and 18 have been applied to the top, arch concrete C is concreted. In the concrete pouring, the range of one pouring of concrete is set as a section, and the sections are successively spliced. However, in the embodiment of FIG. 1 and the embodiment of FIG. The order is different.

First, the embodiment of FIG. 1 will be described.
As shown in the figure, concrete placing section is C ₁ ,
It is divided into C ₂ , …… C ₅ , and first, the leg structure 1 and the required distance C ₅ are placed, that is, the lower part of the support work is placed from the connecting rod 15 of the seismic structure D ahead. Concrete is placed in sections C ₁ and C ₁ . Thereby, the anchor bolts 17, 17
Is embedded in the concrete, and the concrete in the section C ₁ and the seismic resistant structure D are fixedly connected in the width direction of the arch concrete C. In this case, although not shown in the drawing, the separator form, the side form, and the outer form required for placing concrete are properly installed. After that, the sections C ₁ , C ₁ are followed by sections C ₂ , C ₃ , C ₄ and the concrete is successively struck upward, and finally the reinforcing bar 18 is replaced with the axial reinforcing bar 19 of the leg structure 1. After joining, concrete is placed in the sections C ₅ and C ₅ between the initial sections C ₁ and C ₁ and the leg structure 1, and the seismic resistant structure D is embedded in the concrete. Thereby, the entire arch concrete C can be formed.

Next, the embodiment shown in FIG. 2 will be described. Also in the case of this embodiment, the section for placing concrete is set in accordance with the case of the above example, and the sections are spliced.
Between the _first placement section C ₁ and C ₁ and the next placement section C ₂ and C ₂ ,
New section C ₁ , a section over the columns 6 and 6 near C ₁
Setting the C _4, C _4. Then, at the time of placing concrete in the initial sections C ₁ and C ₁ , a seismic resistant structure D similar to the above is embedded in the base end portion at the tip portion thereof to project, and is connected to the tip end portion of the next C ₂ it is to concrete is a C ₂ sections. After that, as in the case of the embodiment of FIG. 1, the top section C ₃
After piling concrete, section C ₄ , between C ₁ and C ₂ ,
And Da設to C ₄ embedding the seismic structure D in its concrete. Finally, similarly to the embodiment of FIG. 1, concrete is buried in the sections C ₅ and C ₅ between the concrete in the section C ₁ and the leg structure 1, and the seismic resistant structure D is placed in the concrete.
Is buried.

The seismic resistant structure D is not limited to that of the embodiment shown in FIGS. The point is to have a structure with high strength and rigidity that can withstand the large horizontal force of the arch concrete C in the width direction. Therefore, various structures other than the structure shown in FIG. 4 are possible. For example, instead of the braces 16, 16, tension wire can be stretched diagonally, and the load-bearing rod 1
It can also be constructed by diagonally combining with 4 and 14. Further, as the means for connecting the seismic resistant structure D and the concrete C, various means other than the above structure can be used. Then, as shown in FIG. 6, a plurality of seismic resistant structures D can be arranged in the thickness direction of concrete. Further, as shown in FIG. 7, steel plates may be combined and welded to form a hollow box 20, and the hollow box 20 may be combined with the leg rods 21 and 21 embedded in the leg structure 1.

[0024]

As described above, according to the construction method of the present invention, a plurality of divided trusses are connected to each other, and each supporting portion is supported by the upright pillars on the ground. Since an earthquake-resistant structure was projected on the structure and the concrete in the initial placement section was joined to the tip of the structure, the concrete in each placement section was successively spliced, so an earthquake occurred during the concrete placement. Even if a large horizontal force acts in the direction orthogonal to the bridge axis, the cast and hardened concrete is integrated with the leg structure through the earthquake-resistant structure, which is excellent in earthquake resistance and also supports It is possible to suppress the application of an excessive horizontal force to, and to prevent deformation and destruction due to an earthquake, which is an excellent effect in improving stability during construction.

[Brief description of drawings]

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

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

FIG. 3 is a schematic plan view of the support work of the present invention.

FIG. 4 is a plan view showing an embodiment of the earthquake-resistant structure according to the present invention.

FIG. 5 is a front view of the same.

FIG. 6 is a front view showing another embodiment.

FIG. 7 is a plan view showing another embodiment of the present invention.

[Explanation of symbols]

A Arch-shaped frame support work B Ground C Arch concrete D Seismic structure a Arch-shaped structure C _{1 to} C ₅ Concrete placing section 1 Leg structure 3 Split truss 4, 5 pin connection 6 Strut 7 Form frame 14 Bearing rod Material 15 Connecting rod 16 Streak 17 Anchor bolt 18, 19 Reinforcing bar

Claims (2)

[Claims] 1. A plurality of arch-shaped structures formed by mutually connecting split trusses each having a length obtained by appropriately dividing the span of arch concrete, are connected in parallel, and the lower end of each arch-shaped structure is connected to a leg structure. In addition to connecting to the trusses, the joints of the divided trusses are supported by the pillars standing upright on the ground, and the arch-shaped frame support work is erected. Anti-seismic structures are provided projecting on both lower ends of the arched formwork support, and the initial placement of arch concrete is done at the required length section on the split truss at the end of the support. Performed by connecting with the tip of the earthquake-resistant structure, then successively piling the concrete upwards, and finally, placing concrete between the concrete of the originally placed section and the leg structure, Seismic structure in the concrete A method of constructing arch concrete by arch-shaped frame support, which is characterized by burying. 2. A plurality of arch-shaped structures formed by mutually connecting split trusses each having a length obtained by appropriately dividing the span of arch concrete, are connected in parallel, and the lower end of each arch-shaped structure is connected to a leg structure. In addition to connecting to the trusses, the joints of the divided trusses are supported by the pillars standing upright on the ground, and the arch-shaped frame support work is erected, and the leg structure has a horizontal external force in the width direction of the arch concrete. Anti-seismic structures are provided projecting on both lower ends of the arched formwork support, and the initial placement of arch concrete is done at the required length section on the split truss at the end of the support. This is done by combining with the tip of the seismic resistant structure, and at the tip of the cast concrete, a seismic resistant structure similar to the above is projected over a pillar close to the cast concrete, and then the split truss. On the adjacent split truss connected to In the required length section, concrete is placed in combination with the tip of the seismic resistant structure, and then concrete is successively sewn upward, and at the end, the concrete and leg structure of the section originally placed A method for constructing arch concrete by arch-shaped frame support construction, characterized in that concrete is cast between the concrete and the section concrete that is placed thereafter, and the seismic structure is embedded in the concrete. ..