JPS62292B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a method for constructing an underwater structure, and in particular, the underwater structure is constructed by using a part of the structure previously constructed on land as a formwork and integrating it with concrete poured underwater. Suggestions on how to build.

Conventionally, the construction method for underwater concrete structures involves attaching a pair of steel formwork to the positioning steel pipe piles via brackets, pouring filling concrete between the formworks, and then filling the formworks in place. Instead, they removed it completely and built an underwater structure. however,
In the case of the conventional construction method described above, since panel-shaped steel formwork is mainly installed in rows, supporting and reinforcing the formwork is difficult and takes time. In particular, for the external formwork of structures, installation accuracy is required due to aesthetic issues, and the work time cannot be shortened. Furthermore, since the main purpose of this structure is to protect the steel pipe piles from collisions with floating objects, consideration must be given to floating objects as the formwork also involves arranging them in rows near the water surface. Therefore, it is weak and unstable against wind and waves. After pouring the filling concrete, it is difficult to remove and recover the formwork, and if it is not recovered, it is environmentally unfavorable.

The purpose of this invention is to overcome the drawbacks of the conventional construction methods described above, and when constructing a concrete structure underwater, it is necessary to prepare a cylindrical concrete outer wall that forms part of the structure wall in advance. The concrete outer wall is cast and formed with reinforcing bars arranged on its inner surface, and this concrete outer wall is installed at a predetermined position along the steel pipe piles fixed above the water surface via a dummy bar, and then the concrete outer wall and the concrete outer wall are installed. After installing the formwork on the inner side of the opposing structure wall, filling concrete is poured between the formwork and forming an integral structure including the cylindrical concrete outer wall as a part thereof. Features. The details of the configuration will be explained below.

Figure 1 of the drawings is a general diagram of a pipe bridge and road bridge that require underwater structures according to the present invention, and Figure 2 is a general diagram of a pipe bridge and a road bridge that require underwater structures according to the present invention.
Figures 3 and 3 show details of the underwater foundation. The illustrated underwater structure is an example of a pillar base, and has a structure in which a cylindrical structure wall 1 is supported at a predetermined position by a plurality of steel pipe piles 2 driven into the soil. To explain the underwater structure according to the construction of the present invention in the order of construction steps, a cylindrical concrete outer wall 3 forming an outer peripheral wall and a formwork 4 forming an inner peripheral wall are prepared in advance,
After that, it is constructed by a process of pouring filling concrete 5.

The formwork includes a cylindrical concrete inner wall,
A cylindrical steel inner wall or a panel steel formwork is used. The illustrated example uses a cylindrical shell-shaped concrete interior and an exterior wall, and 6 and 6' are reinforcing bars to be buried. Reference numeral 7 is a reinforcing reinforcing bar protruding from the steel pipe pile, and may be welded to the steel pipe pile in advance, or may be welded after the concrete outer wall 3 is installed.
This is the reinforcement arrangement. The details of the reinforcement arrangement are shown in Fig. 4. Reference numeral 8 shown in Fig. 4 is a reinforcing reinforcing bar that strengthens the integral connection between the inner and outer walls 3, 4 and the filling concrete 5, and extends from the support plate 9 buried in each wall toward the filling concrete placement space. It is fixed in the set shape. Although reinforcement is not particularly shown in the case where a cylindrical steel inner wall is used as a formwork, reinforcement is arranged in the same way as for a concrete inner wall, but in this case, it is attached to the formwork 4 by welding.

The reason why a steel interior can be used is that there is no need to consider the appearance of steel corrosion on the inside of the structure, and since it is protected by the concrete exterior wall 3, consideration should be given to damage and deformation caused by collisions with floating objects, etc. This is because there is no need for it, and the weight can be reduced, making it disposable.

Furthermore, if a panel-shaped steel formwork that has been pre-assembled on land is used for the inner surface, the reinforcing bars 8 protruding from the concrete outer wall 3 can be extended close to this formwork, and only a few on-site reinforcements are required. It will not be an impediment to the work done. The advantage of this formwork, as will be explained later, is that it is economical because it can be removed one by one and reused when dividing it into several blocks to ensure the required height for the structure or when constructing structures of the same shape. It is true.

In short, one of the features of the construction method of the present invention is that the parts that make up the inner and outer walls of the structure are prepared on land in advance, and while this can be used in place of conventional formwork, it can also be used as part of the structure. By integrating it with concrete 5, and by using a panel-shaped steel formwork, etc., which was also assembled integrally on land using the concrete outer wall previously created on land, for the inner frame, the inner and outer formwork of the structure can be In addition to omitting on-site assembly work, the work for reinforcing reinforcement is also minimized.

FIG. 5 shows each stage of the construction method of the present invention. First, the concrete outer wall 3 constituting the outer wall of the structure is manufactured on land in advance. At the same time, a steel pipe pile 2 is driven into the underwater installation position, and brackets 12, 12' for supporting the concrete outer wall 3 at a predetermined position underwater are fixed to the steel pipe pile 2. Since the fixed positions of the brackets 12, 12' are underwater, for convenience of work, dummy bars 12a, 12'a are provided protruding from the brackets and brought above the water surface along the stakes. Weld and fix the upper part located at , and determine the bracket position. The concrete outer wall 3 is supported underwater on the thus prepared steel pipe pile 2 by means of a crane ship 10 and a barge 11 via brackets 12 and 12'. Thereafter, an inner formwork 4 made of concrete or steel for forming the inner wall is installed concentrically with the outer wall 3. The details of the concrete outer wall 3 and the support pattern of the formwork 4 are shown in FIGS. 6 and 7.

After completing the above steps, filling concrete 5 is placed between the concrete outer wall 3 and the inner formwork 4 using the tremie pipe 14. During this pouring,
To prevent the filling concrete from flowing out,
An embankment 13 as shown in FIG. 9 is constructed in advance.

After that, if it is necessary to construct the foundation in several blocks in order to obtain the required height for the underwater foundation, repeat the above-mentioned steps as shown in Fig. 5 (d) and (e). Filling concrete 5 is placed between the concrete outer wall 3 and the inner formwork 4, joint treatment is performed by pouring mortar into both joints, and the concrete is overlaid to the required height to complete the work.

Example: The effect of the present invention was confirmed in the construction of a piping bridge column pedestal foundation in the construction of a pipeline across the Takahashi River, which will transport C gas and N gas generated at the Mizushima Steel Works to a factory on the opposite bank of the Takahashi River. An example in which the method of the present invention was applied on a trial basis will be explained below. Figures 10A and 10B are detailed views of the foundation, which has an oval column base of 7.8m in length, 4.3m in width, and 9.4m in height. Pillar base wall thickness 80cm
Of these, the 15cm concrete outer wall is 4.5m high.
I used blocks that had been made in advance on land. Furthermore, as the inner formwork for the structure, we used a panel-shaped steel formwork that was divided into four blocks and assembled into one piece on land using bolts. As a result of this example, the construction period is approximately
The time was saved by 10 days, and the work went very smoothly.

As explained above, according to the present invention, since the concrete outer wall and the concrete inner wall or the steel inner wall also serve as formwork, there is no need to assemble or remove the formwork underwater or on the water. Even if steel formwork is used, there is no need for on-site assembly, and only clearing is required. In any case, since there is almost no need for on-site work such as bar arrangement or underwater work, the construction work is simple and can be shortened, and it is superior to conventional methods in terms of aesthetics.

[Brief explanation of the drawing]

Figure 1 is a front view showing a general example of a column base foundation;
A and B in Fig. 2 and A and B in Fig. 3 are a cutout plan view and a cutout front view of an underwater structure adopted in the construction example of the present invention, and A and B in Fig. 4 are the structure. A partial cross-sectional view of the object wall, Figure 5 is a process diagram showing each step of the construction method of the present invention, Figure 6 A and B are cross-sectional views showing the pattern of concrete outer wall and formwork support by brackets, Figure 7 is a front view showing details of the bracket, Figures 8 and 9 are sectional views of the embankment constructed under the structure, and Figure 10 A and B are cutaway sectional views of the column base of the example. It is. 1... Underwater structure wall, 2... Steel pipe pile, 3...
Concrete external wall, 4...Formwork (for internal wall), 5
...Filled concrete, 6,6',7,8...Reinforcement bar, 9...Support plate, 10...Crane ship, 11...
...Barge, 12, 12'...Bracket, 12a,
12'a... Bracket dummy bar, 13...
Seishi, 14...Tolemy tube.

Claims (1)

[Claims] 1. When constructing a concrete structure underwater, a cylindrical concrete outer wall constituting a part of the structure wall is cast in advance with reinforcing bars arranged on its inner surface, and The concrete exterior wall is installed in a predetermined position along the steel pipe pile fixed above the water surface using a temporary bracket via a dummy bar, and then the formwork for the inner surface of the structure wall facing the concrete exterior wall is installed, and then the form is removed. A method for constructing an underwater structure, which comprises placing filling concrete between the structure and the frame to form an integral structure including the cylindrical concrete outer wall as a part thereof. 2. The construction method according to claim 1, wherein the formwork is a cylindrical shell-shaped concrete wall. 3 Claim 1, wherein the formwork is a steel frame
Construction method described in.