JP5687162B2 - Overhang head rail structure in concrete dam and overhang head rail construction method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an overhang structure for a concrete dam and a construction method for an overhang section, and more particularly to a structure in which the overhang and an overhang at the top end of a concrete dam are precast concrete and a construction method therefor.

  An overhead rail is provided on the top of the concrete dam in order to prevent a passerby (car) or the like from falling. Moreover, the dam dam body top part which is a part in which this handrail part is installed is provided with the overhang | projection part in the upstream / downstream part.

  Conventionally, the construction of this overhang has been done after the construction of the dam body has been completed and the formwork for the dam has been removed, then the scaffolding bracket is installed, the scaffolding is assembled on the bracket, and the formwork for the overhanging part After assembling the supporting work, assembling the reinforcing bars in the formwork (rebaring), and then placing the concrete.

  In addition, the construction of the balustrade installed on the upper part of the overhanging portion is performed after placing the concrete of the overhanging portion, installing the formwork of the balustrade, assembling the reinforcing bars, and then placing the concrete. The construction method of pre-cast concrete made in advance as in the technique described in Patent Document 1, and installed and fixed to the upper surface of the overhanging portion by a cable crane The method is taken.

  Regardless of the construction method when placing the balustrade in concrete or when installing and fixing the precast balustrade, after the dam dam body construction is completed and the dam formwork is removed as described above Bracket mounting, scaffold assembly, formwork support assembly, rebar assembly, concrete placement, railing installation (concrete placement or precast railing installation and fixing), formwork support dismantling / removal, scaffolding Since each work of dismantling / removal and removal of the bracket for scaffolding is essential, it is necessary to secure and arrange the work period, labor, and specialized technicians for each work. It was found that it was not easy to achieve each item such as labor saving, labor saving, shortening of process and construction period, ensuring quality, ensuring safety, etc.

Japanese Patent No. 3663594

  Therefore, the object of the present invention is to achieve each item such as labor-saving, labor-saving, shortening the process and construction period, ensuring quality, ensuring safety, etc. when installing the overhang and railing in dam construction It is providing the overhang part railing structure in a concrete dam, and the overhang part railing construction method.

  The present invention for solving the above problems has the following configuration.

1. In the structure of the overhanging part and the balustrade part in the upstream and downstream part of the concrete dam crest,
The overhang portion and the balustrade portion disposed on the upper portion of the overhang portion are composed of an overhang balustrade member formed of precast concrete having an integrated structure ,
An overhang portion of the overhang rail member disposed on the upstream side and an overhang portion of the overhang rail member disposed on the downstream side are disposed in a stretched state between the two overhang portions. Being connected by the second reinforcing steel material,
Overhanging portion railing section structure in the concrete dam, wherein.

2. 2. The overhanging column in the concrete dam according to the above 1, wherein the overhanging column member is fixed by a fixing configuration that is fixed to a lift immediately below a bank body in which the member is disposed. Part structure.

3. The anchoring configuration is
The first reinforcing steel material is provided on the lift directly below the bank body on which the overhang bar member is disposed so that the upper half projects from the upper surface of the lift and on the inner side of the position where the overhang bar member is disposed. Buried,
The projecting portion of the projecting rail member disposed on the upper surface of the lift is configured to be fixed by being connected to the upper half of the first reinforcing steel material by connection means such as welding,
The overhanging railing structure in the concrete dam as described in 2 above.

4 . 4. The overhanging column structure in a concrete dam as described in 3 above, wherein the first reinforcing steel material and the second reinforcing steel material are connected by connection means such as welding.

5 . In the construction method of the overhanging part and the railing part in the upstream and downstream part of the concrete dam crest part,
The overhang portion and the balustrade portion disposed on the upper portion of the overhang portion are previously formed by precast concrete made of an integrated structure,
The overhang rail member which is the overhang height rail made of precast concrete of this integrated structure is installed and fixed on the upper surface of the lift directly below the overhang rail member ,
The second overhang rail member arranged on the upstream side and the overhang rail member arranged on the downstream side are arranged in a stretched state between the respective overhang portions of the two overhang column members. After connecting with a reinforcing steel material, placing concrete up to the lower position of the balustrade on the upper surface of the lift,
The overhang part railing construction method characterized by this.

6 . When the lift is placed directly below the bank body on which the overhang bar member is disposed, the first reinforcement is provided so that the upper half of the upper surface of the lift protrudes inward from the position where the overhang bar member is disposed. Buried steel,
When the overhang rail member is arranged on the upper surface of the lift, the overhang portion of the overhang rail member and the upper half of the first reinforcing steel material are connected by connection means such as welding,
6. The overhanging railing construction method according to 5 above.

7 . 7. The overhang railing construction method according to claim 6 , wherein the first reinforcing steel material and the second reinforcing steel material are connected by connection means such as welding.

8 . The overhang height column according to any one of 5 to 7 above, wherein a dam formwork used in a lift immediately below the bank is used as a scaffold for the installation and fixing work of the overhang height member. Construction method.

According to the invention shown in claim 1 or 5 , each of the labor saving, manpower saving, process and construction period shortening, quality ensuring, safety ensuring, etc. in the installation of the overhang part and the railing part in the dam construction The overhang part railing structure and the overhang part railing construction method in a concrete dam capable of achieving the items can be provided.
In particular, it is possible to increase the bonding strength between the overhang rail member disposed on the upstream side and the overhang rail member disposed on the downstream side, and with the concrete placed between the upstream and downstream overhang portions. Strength can be improved by contributing to integration (adhesion).

In particular, by making the overhang part and the balustrade part not only precast but also having an integrated structure, the overhang part can be used as an in-situ formwork and the next balustrade process can be omitted. Formwork and rebar work are not required for the construction of the projecting part and railing part. Therefore,
(1) A long-term concrete placement stop can be avoided to shorten the process and the construction period.
(2) Special work such as formwork and rebar work is not required, and it is possible to work with a small number of people, saving labor and labor.
(3) By avoiding long-term neglect, the generation of internal temperature stress in discontinuous dam body can be prevented, and the quality of dam concrete can be secured.
(4) The safety of construction is significantly improved by preventing accidents such as falling and falling objects during formwork.
(5) Excellent environmental suitability due to the reduction of waste materials such as formwork and temporary materials.
There is a remarkable effect.
As an example, in the case of the site of the overhang section railing structure where the construction period is 50 days in the conventional structure, according to the present invention, the construction period is 20 days, and the construction period can be reduced to half or less.

  According to the invention shown in claim 2, it is possible to reinforce the shear resistance of the overhang rail member.

According to the invention described in claim 3 or 6 , since the joining strength between the overhang rail member and the lift directly below can be increased, the shear resistance of the overhang rail member can be further reinforced.

According to the invention shown in claim 4 or 7 , it is possible to further increase the bonding strength of the three members of the lift immediately below, the upstream protruding column member, and the downstream protruding column member.

According to the invention shown in claim 8 , the bracket, the scaffold and the supporting work, which are necessary in the conventional overhang construction and railing construction, can be omitted, and the dam mold used up to the construction of the direct lift By using a frame,
(A) Remove the dam formwork after the construction of the dam body
(B) installation of scaffolding brackets;
(C) scaffold assembly,
(D) Form support assembly
Therefore, it is possible to shorten the process and the construction period.
In addition, after the installation of the overhang rail section is completed,
(E) Formwork support work dismantling and removal,
(F) Scaffold dismantling / removal,
(G) Removal of bracket for scaffolding,
Since each of these operations is naturally unnecessary, the process and construction period can be further shortened.

The principal part schematic sectional drawing which shows one Example of the overhang part railing part structure in the concrete dam which concerns on this invention The schematic front view and schematic side view which show one Example of the overhang rail member preferably used for this invention Main part schematic sectional drawing which shows 1 process of one Example of the overhang part railing construction method which concerns on this invention FIG. 3 is a schematic cross-sectional view of the main part showing the next step of FIG. FIG. 4 is a schematic cross-sectional view of the main part showing the next step of FIG. FIG. 5 is a schematic cross-sectional view of the main part showing the next step of FIG. The principal part schematic sectional drawing which shows the other Example of the adhering structure of the overhang rail member and the lift directly under a bank body The principal part schematic sectional drawing which shows the other Example of the adhering structure of the overhang rail member and the lift directly under a bank body

  Hereinafter, the overhang part railing structure and the overhang part railing construction method in the concrete dam according to the present invention will be described in detail with reference to the accompanying drawings.

  The present invention relates to a projecting portion that is a structure for projecting a non-overflow portion of a concrete dam ridge top portion to both the upstream and downstream sides, and laying on the ridge top portion by being disposed on each of the overhang portions. This is a technology that secures the road portion to be used and makes the balustrade portion that functions as a safety fence into precast concrete and has an integrated structure.

That is, as shown in FIG.1 and FIG.2, this invention is in the structure of the overhang | projection part and balustrade part in the upstream and downstream part of a concrete dam crest part,
The overhanging portion 11 and the balustrade portion 12 provided on the upper portion of the overhanging portion 11 are composed of an overhanging balustrade member 1 formed of precast concrete having an integrated structure.

  The overhang rail member 1 is precast concrete molded into a desired shape, size, and required strength in a factory in advance and then carried to the site. As a structural material made of this type of precast concrete, a publicly known configuration is used. It can be taken without any special restrictions.

  The size of the overhang column member 1 is appropriately set according to the design conditions of the concrete dam to be applied, but the thickness per unit is about 350 mm, the overhang amount is about 350 mm, and the height is about An example is about 2300 mm, a length of about 2500 mm, and a weight of about 5 tons. In addition, the desired size is appropriately set depending on the design conditions of the concrete dam to be applied to the overhang amount and height / thickness of the overhang portion 11 and the height / thickness of the balustrade portion 12.

The overhang rail member 1 is a structure fixed by an adhering structure that is fixed to a lift 2 directly below a bank body in which the overhang rail member 1 is disposed,
As a preferable fixing configuration,
The lift 2 immediately below the bank body on which the overhang bar member 1 is disposed is arranged so that the upper half projects from the upper surface of the lift 2 to the inner side of the position where the overhang bar member 1 is disposed. 1 Reinforced steel 3 is embedded,
The overhanging section 11 of the overhanging column member 1 disposed on the upper surface of the lift 2 is fixed by being connected to the upper half of the first reinforcing steel material 3 by connecting means 4 such as welding. .

  The first reinforcing steel material 3 is installed by burying the lower half part in the lift 8 in a state where the upper half part protrudes when the above-described lift 2 is placed. A publicly known steel material can be used as the reinforcing steel material for the concrete structure of the present invention without any particular limitation. For example, a plurality of H-shaped steels having a length of H-100 × 100 and a length of 650 mm (one overhang rail member 1) It is possible to adopt a configuration in which about 4 to 6 pieces are arranged side by side.

  As the connecting means 4 for connecting the overhang bar member 1 and the first reinforcing steel member 3, an anchor member is inserted and fixed to an insert 13 disposed on the inner surface of the overhang part 11 of the overhang bar member 1, A method of welding the anchor member to the first reinforcing steel material 3 can be exemplified.

  The bonding strength between the overhanging column member 1 and the directly below lift 2 is increased by fixing and connecting the overhanging portion 11 of the overhanging column member 1 to the first reinforcing member 3 embedded in the directly below lift 2. Therefore, the shear resistance of the overhang rail member 1 can be further reinforced.

Further, in this embodiment, the overhanging portion 11 of the overhanging column member 1 disposed on the upstream side of the upper surface of the lift 2 and the overhanging portion 11 of the overhanging column member 1 disposed on the downstream side are By adopting a configuration in which the two reinforcing steel members 5 arranged between the two overhanging portions 11 and 11 are connected in a bridging state, the overhanging column member 1 arranged on the upstream side and the downstream side are arranged on the downstream side. The joint strength with the overhanging column member 1 can be increased, and the strength is improved by contributing to the integration (attachment) with the concrete 6 placed between the upstream and downstream overhanging portions 11 and 11. be able to.

  The second reinforcing steel member 5 is connected to the overhang rail member 1 by inserting and fixing an anchor member to an insert 14 disposed on the upper inner surface of the overhang portion 11 of the overhang rail member 1. The method of welding-connecting to the steel material 5 can be mentioned.

  Further, in this embodiment, the first reinforcing steel member 3 and the second reinforcing steel member 5 are connected by connecting means such as welding, so that the lift 2 directly below, the overhanging column member 1 on the upstream side and the downstream side are connected. The joint strength of the three members of the overhanging column member 1 on the side can be further increased.

  Next, an embodiment of a construction method for the overhanging rail section structure having the above-described configuration will be described with reference to FIGS.

  When the construction of the concrete dam body progresses and the construction of the lift 2 directly below (that is, the uppermost lift of the dam body), which is the part where the overhang rail member 1 of the present invention is installed and fixed, is shown in FIG. As shown in the drawing, when placing concrete on the lift 2 directly below, the first reinforcing steel material is such that the upper half of the upper surface of the lift 2 protrudes to the inner side from the position where the overhanging column member 1 is disposed. 3 is buried.

After the construction of the direct lift 2 is completed, as shown in FIG. 4, the overhang rail member 1 is suspended and carried to the site construction position by the cable crane 8 and installed on the upper surface of the direct lift 2. The installed overhang rail member 1 is connected and fixed to the first reinforcing steel member 3 by the connecting means 4. Furthermore, the overhang height column member 1 disposed on the upstream side of the upper surface of the lift 2 and the overhang height column portion 1 disposed on the downstream side are respectively connected to the overhang portions 11 of the two overhang height column members 1. -It connects by the 2nd reinforcement steel material 5 arrange | positioned between 11 in a bridging state. Furthermore, the 1st reinforcement steel materials 3 * 3 and the 2nd reinforcement steel materials 5 are connected. In addition, when performing the installation and fixing work of the overhang rail member 1, a safe working environment can be efficiently achieved by using the dam formwork 7, 7 used for the construction of the concrete dam body without dismantling. Can be secured well.

  Next, as shown in FIG. 5, the concrete is placed by the concrete placement machine 9 up to the upper surface of the lift 2 and below the height sections 12, 12 of the overhanging sections 1, 1.

  After confirming the curing of the cast concrete 6, the construction of the overhanging section of the concrete dam is completed by dismantling and removing the dam molds 7, 7 as shown in FIG.

  As mentioned above, although the overhang part balustrade structure and the overhang part balustrade construction method in the concrete dam concerning this invention were demonstrated based on the Example, this invention is not limited to the said Example, Other within the scope of the present invention. It is also possible to adopt the embodiment.

  For example, in the said Example, although the overhang rail member 1 is set as the structure which formed the overhang part 11 and the balustrade part 12 with the same thickness, this invention is not limited to this structure, but is higher than the overhang part 11. The portion 12 may be formed thick or thin.

  Further, as shown in FIG. 7, it is possible to provide a structure in which a recess 21 is provided in the lift 2 directly below, and a protrusion 15 that fits into the recess 21 is formed on the lower surface of the overhanging column member 1. In addition, according to this aspect, it becomes easy to install and fix the overhang rail member 1 to the upper surface of the lift 2 immediately below. Even in the case of this embodiment, it is preferable to use the first reinforcing steel material 3 and the second reinforcing steel material 5 of the above-described embodiment together.

  Furthermore, as shown in FIG. 8, the reinforcing bar 22 is embedded at the position where the overhanging column member 1 is disposed so that the upper half protrudes from the upper surface of the lift 2 directly below, and from the bottom surface of the overhanging column member 1. It can also be set as the structure which formed the penetration hole 16 in which the said reinforcing bar 22 for insertion is penetrated inside. According to such a configuration, the overhang rail member 1 can be installed and fixed in a state where the joining rebar 22 is inserted from the bottom surface to the lift 2 directly below. Even in the case of this aspect, it is preferable to use together with the first reinforcing steel material 3 and the second reinforcing steel material 5 of the above-described embodiment.

DESCRIPTION OF SYMBOLS 1 Overhang rail member 11 Overhang part 12 High rail part 13 Insert 14 Insert 15 Protrusion part 16 Insertion hole 2 Lift just below 21 Recess part 22 Joining rebar 3 1st reinforcement steel material 4 Connection means 5 2nd reinforcement steel material 6 Casting concrete 7 Form for dam 8 Cable crane 9 Concrete placement machine

Claims (8)

In the structure of the overhanging part and the balustrade part in the upstream and downstream part of the concrete dam crest,
The overhang portion and the balustrade portion disposed on the upper portion of the overhang portion are composed of an overhang balustrade member formed of precast concrete having an integrated structure ,
An overhang portion of the overhang rail member disposed on the upstream side and an overhang portion of the overhang rail member disposed on the downstream side are disposed in a stretched state between the two overhang portions. Being connected by the second reinforcing steel material,
Overhanging portion railing section structure in the concrete dam, wherein. 2. The overhang portion in a concrete dam according to claim 1, wherein the overhang rail member is fixed by a fixing structure that is fixed to a lift directly below a bank body in which the member is disposed. The balustrade structure. The anchoring configuration is
The first reinforcing steel material is provided on the lift directly below the bank body on which the overhang bar member is disposed so that the upper half projects from the upper surface of the lift and on the inner side of the position where the overhang bar member is disposed. Buried,
The projecting portion of the projecting rail member disposed on the upper surface of the lift is configured to be fixed by being connected to the upper half of the first reinforcing steel material by connection means such as welding,
The overhanging railing structure in a concrete dam according to claim 2. 4. The overhanging column structure in a concrete dam according to claim 3 , wherein the first reinforcing steel material and the second reinforcing steel material are connected by connection means such as welding. In the construction method of the overhanging part and the railing part in the upstream and downstream part of the concrete dam crest part,
The overhang portion and the balustrade portion disposed on the upper portion of the overhang portion are previously formed by precast concrete made of an integrated structure,
The overhang rail member which is the overhang height rail made of precast concrete of this integrated structure is installed and fixed on the upper surface of the lift directly below the overhang rail member ,
The second overhang rail member arranged on the upstream side and the overhang rail member arranged on the downstream side are arranged in a stretched state between the respective overhang portions of the two overhang column members. After connecting with a reinforcing steel material, placing concrete up to the lower position of the balustrade on the upper surface of the lift,
The overhang part railing construction method characterized by this. When the lift is placed directly below the bank body on which the overhang bar member is disposed, the first reinforcement is provided so that the upper half of the upper surface of the lift protrudes inward from the position where the overhang bar member is disposed. Buried steel,
When the overhang rail member is arranged on the upper surface of the lift, the overhang portion of the overhang rail member and the upper half of the first reinforcing steel material are connected by connection means such as welding,
The overhang part railing construction method of Claim 5 characterized by these. 7. The overhang railing construction method according to claim 6 , wherein the first reinforcing steel material and the second reinforcing steel material are connected by connection means such as welding. The overhang height bar according to any one of claims 5 to 7 , wherein a formwork for a dam used in a lift immediately below the bank body is used as a scaffold for installation and fixing work of the overhang height column member. Part construction method.

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