JPS6138977Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to breakwater structures such as breakwaters or coastal seawalls.

Wavebreak structures constructed on underwater ground are susceptible to the effects of waves, so construction work would be impossible unless a high level of calmness could be achieved continuously. To solve this problem, Utility Model Registration No. 1307202 was devised. Although the present invention has many advantages, when the pile is mainly made of steel, the pile head, where the greatest structural stress occurs, is the part that undergoes repeated drying and humidity, and therefore the steel pile is most susceptible to corrosion. Therefore, in order to create a safe wave-break structure, the portion of the pile head above the low tide surface must be completely protected from corrosion, and for this reason, it is generally necessary to cover the pile head with reinforced concrete or the like.
However, since waves are constantly acting near the low tide level, it is extremely difficult to attach formwork to the pile heads, and construction cannot be carried out for a long period of time because a certain number of calm days cannot be obtained, resulting in the greatest increase in construction costs. This was a major cause. The present invention eliminates this drawback and will be explained by way of example. Figure 1 is a top plan view of the pile used in this invention, where 1 is an H steel pile, and 2 is a flat iron that fits exactly into the part formed by the flange and belly plate of the H steel pile. It is a welded bottom plate, and a small hole 3 is provided in a part of the bottom plate.
4 is a side plate, which is a flat iron welded to the end of the bottom plate and the flange end of the H steel. Thus, a cylindrical enclosure (hereinafter simply referred to as a "tube") 5 is formed by the flange of the H steel pile, the belly plate, the bottom plate 2, and the side plates 4. When the pile 1 of the present invention is installed on the underwater ground,
As shown in Figure 2, the bottom plate 2 is underwater at high tide.
Therefore, water is contained inside the cylinder 5. However, in the present invention, a small hole 3 is provided in a part of the bottom plate 2, so if concrete is poured gently into the tube 5, the water in the tube 5 will flow out through the small hole 3, and the concrete will not be filled. As the disease progresses, the small hole 3 naturally closes. Further, when the bottom plate 2 comes out on the water at low tide, the water in the tube 5 naturally flows out. If the small holes 3 were not provided, water would remain in the tube 5 even if the bottom plate 2 rose above the water at low tide, which would hinder the filling of concrete. Because of the small holes 3, the water inside the cylinder 5 can be easily drained out not only when the bottom plate 2 is above water but also when it is underwater, so it is easy to pour concrete into the cylinder 5. can be filled. Therefore, when the H-steel pile 1 is installed on underwater ground, the inner surface of the H-steel pile, which is the part that repeats wet and dry conditions where corrosion is most severe, can be completely covered with concrete. FIG. 3 is a cross-sectional view of one embodiment of a wave-break structure constructed using ordinary H-steel piles. Ordinary H-steel piles 1' are installed on the underwater ground at appropriate intervals, the heads of the piles are connected with a plurality of horizontal bars 6 to form a rectangular cylindrical enclosure, and the inside of the enclosure is A wave-absorbing material 7 such as stones or concrete blocks of a size large enough to prevent escape from the gaps between the piles is filled in the piles, and the heads of the piles are firmly connected with cast-in-place concrete 8. At this time, the largest moment is generated at the head of the pile, but the parts that repeatedly experience dryness and humidity of 10 or more around the high tide level experience the greatest corrosion. According to the same commentary, pages 3-10, published by the Japan Ports and Harbors Association, the corrosion rate is 0.3 mm/min above the high tide level.
The distance between the high tide surface and the ocean floor is 0.1 mm/year. Therefore, above the high tide level, for example, approximately 9
mm, and approximately 3 mm will be lost due to corrosion between the high tide surface and the seabed surface. Therefore, above the high tide level, the structurally most important flanges of H-steel piles wear out by 9 mm on both sides, totaling 18 mm, leaving only a small portion of the original shape, and the pile cannot withstand the moment at the head. Therefore, as shown in Figure 3, around the high tide level 10,
Alternatively, it was necessary to cover the H steel pile above an appropriate position between the high tide level 10 and the low tide level 9 with concrete 8. This was an absolute structural requirement. However, in order to cover the H-steel pile, it is first necessary to attach the bottom plate of the formwork around the H-steel pile, and this work is extremely difficult because the attachment point is easily affected by waves. It was hot. In addition, in areas with large tidal differences, corrosion progresses at a rate of 0.1 mm/year over the entire surface of the H steel pile in the area below the lower surface of the cast-in-place concrete 8 where drying and humidity are repeated, so the wear and tear on the entire cross section of the H steel pile is extremely big. Although the work of cast-in-place concrete 8 is extremely difficult, it is necessary to lower it as low as possible to prevent corrosion of the H-steel pile, which increases the height a of cast-in-place concrete 8.
Since the wave force acts directly on the entire surface of a, the influence of external force becomes very large. In other words, there were disadvantages in that the stress was large and the cross section of the pile had to be large. On the other hand, Fig. 4 shows an embodiment of the wave-break structure of the present invention, in which the bottom plate 2 of the cylinder 5 is below the low tide level, and the concrete inside the cylinder 5 is underwater concrete. Since there is no wear on the pile's belly plate and only on one side of the flange, corrosion wear is reduced to less than half that of conventional piles as shown in Figure 3, and the structure of the H steel pile as a whole is improved. The wear and tear on the most important parts will be very small. Therefore, it is sufficient to cast in place concrete 8 at the pile head from a position above the high tide level. As a result, the height b of the cast-in-place concrete 8 becomes smaller than a in the conventional structure shown in Fig. 3, so the surface on which the wave force directly acts becomes smaller, which is not only very advantageous in terms of stress, but also makes it possible to cast-in-place concrete. Since it is easier to attach the concrete formwork, the concrete casting itself is also easier, the amount of concrete is reduced, and overall construction is easier and construction costs can be greatly reduced.

[Brief explanation of the drawing]

Figure 1: Plan view of H steel pile, Figure 2: Side view, Figure 3: Cross-sectional view of conventional wave-break structure, Figure 4:
Figure: Cross-sectional view of the wave-break structure of the present invention. 1, 1...Pile, 2...Bottom plate, 3...Small hole, 4...
...Side plate, 5...Cylindrical enclosure, 6...Horizontal bar, 7...
Wave-dissipating material, 8... Cast-in-place concrete, a, b...
Height of cast-in-place concrete.

Claims (1)

[Scope of utility model registration request] A flat iron is welded to the part of the H steel pile near the water surface where the pile is repeatedly wetted and dried after it is installed on the underwater ground to form the bottom plate 2, and a small hole is provided in a part of the bottom plate, Furthermore, flat iron is welded to the bottom plate and the flange ends of the H steel piles to form a cylindrical enclosure, and a large number of piles for constructing underwater structures are filled with concrete between each pile. The inside of the rectangular tube-shaped lattice frame is formed by placing the piles in a rectangular tube shape with a slight gap between them and establishing them on the underwater ground, and connecting the heads of each of these piles with a rectangular frame having a plurality of horizontal bars. The gaps between the piles of this rectangular cylindrical lattice frame are filled with wave-absorbing materials such as stones or concrete blocks that are large enough to prevent them from escaping, and the heads of each pile are covered with steel frames, reinforcing bars, or cast-in-place concrete. A wave-break structure made up of strong connections.