JPS6042121Y2 - Piles for constructing underwater structures - Google Patents

Description

[Detailed explanation of the idea] Concerning piles for constructing underwater structures such as rivers and ports.

Although structural H-steel piles have many advantages, when they are used as construction materials for underwater structures, the large surface area of H-steel piles causes significant corrosion and wear, and measures must be taken to sufficiently prevent this. In some cases, it may become unusable.

Corrosion prevention methods such as cathodic protection are available, but they are less efficient and expensive in areas with rough waves, such as those directly facing the open sea.

The present invention simply eliminates the above drawbacks and will be explained by way of examples.

FIG. 1 is a top plan view of the pile of the present invention, and FIG. 2 is a side view of FIG. 1.

1 is an H steel pile, 2 is a bottom plate made of flat iron welded to fit exactly into the shape formed by the flange and belly plate of the H steel pile, and a small hole 3 is provided in a part of the bottom plate. .

4 is a side plate made of 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 cylindrical enclosure) 5 is formed by the flange 1, belly plate, bottom plate 2, and side plates 4 of the H steel pile.
is expressed.

When the pile 1 of the present invention is installed on underwater ground, the bottom plate 2 is underwater at high tide, as shown in FIG. 2, and therefore the inside of the tube 5 is filled with water.

However, in the present invention, since the small hole 3 is provided in a part of the bottom plate 2, if concrete is poured into the cylinder 5 gently, the cylinder 5
The water inside flows out from the small hole 3, and the small hole 3 naturally closes as filling with concrete progresses.

Without the small holes 3, even if the bottom plate 2 rises above the water at low tide, water will remain in the tube 5, which will hinder the filling of concrete.

In the present invention, since there is a small hole 3, when the bottom plate 2 comes out on the water at low tide, the water in the tube 5 naturally flows out.

In this way, the water in the tube 5 can be easily drained out not only when the bottom plate 2 is above water but also when it is underwater, so that the tube 5 can be easily filled with concrete.

Therefore, when the H-steel pile 1 is installed on underwater ground, the inner surface of the H-steel pile, which is exposed to repeated 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, and the heads of the piles are connected with a plurality of horizontal bars 6 to form a rectangular cylindrical enclosure. A wave-dampening material 7 such as a stone or a concrete block is filled with a size that does not escape from the gap between the piles, and the head of the pile is firmly connected with cast-in-place concrete 8.

At this time, the largest moment is generated at the head of the pile, but the corrosion is greatest in the part that repeats tidal flats above the high tide level.According to the design standards for ports, etc., the corrosion rate is higher than the high tide level. 0.3m/year, 0.1mm between high tide and low tide
/ year.

Therefore, above the high tide level, for example, for a distance of 3 cm, it is approximately 911 rI.
Approximately 31rr of IL1 will be lost due to corrosion between the high tide and low tide levels of IL1.

Therefore, above the high tide level, the flanges of H-steel piles, which are structurally important, wear out 97rrIIt on each side, a total of 18rIrIIt, leaving only a small portion of the original shape, unable to withstand the moment of the pile head.

Therefore, as shown in Figure 3, the area is around high tide level 10 or high tide level 1.
It was necessary to cover the upper H steel pile with concrete 8 from an appropriate position between 0 and low tide level 9.

This was an absolute structural requirement.

However, in order to cover the H-steel pile, it was first necessary to attach a bottom plate around the H-steel pile, and this work was extremely difficult because the installation location was easily affected by waves. .

In addition, in areas with large tidal differences, corrosion of H steel piles progresses over the entire surface at a rate of 0.1 mm/year in areas that repeat tidal flats below the bottom surface of cast-in-place concrete 8, so the wear and tear on the entire cross section of H steel piles is extremely high. big.

Although the cast-in-place concrete 8 is extremely difficult to work with, it is necessary to avoid it as low as possible due to the corrosion of the H-steel piles, so the height a of the cast-in-place concrete 8 increases, and the wave force increases to a. Since it acts on the entire surface, the influence of external forces becomes very large.

Therefore, there was a drawback that the stress increased and the cross section of the pile also had to be made larger.

On the other hand, FIG. 4 shows an example of a wave-break structure using H steel piles of the present invention, in which the bottom plate 2 of the cylinder 5 is below the low tide level,
The concrete inside tube 5 is underwater concrete, but in this case there is no wear on the H steel piles and no damage to the bottom plate.
Since the flange is also only on one side, the corrosion wear is reduced to 172 or less compared to the conventional one as shown in Fig. 3, and the wear of the H steel pile as a whole is extremely small.

Therefore, it is sufficient to cast in place concrete 8 at the pile head from a position above the high tide level.

Therefore, the height b of the cast-in-place concrete 8 is smaller than the height a of the conventional structure shown in FIG.
Cast-in-place concrete placement itself is easy, the amount of concrete is small, and overall construction is easy and construction costs can be greatly reduced.

[Brief explanation of drawings]

Figure 1... Plan view of H steel pile, Figure 2...
・Side view, Fig. 3...A sectional view of a conventional wave-break structure, Fig. 4...A sectional view of a wave-break structure using the H steel pile 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, tail ...Cast-in-place concrete.

Claims (1)

[Scope of utility model registration request] A flat iron is welded to the bottom plate 2 of the H steel pile near the water surface where the pile is repeatedly dried and moistened after it is installed on the underwater ground, and a small hole is provided in a part of the bottom plate. A pile for constructing an underwater structure is made by welding flat iron to the bottom plate and the flange end of the H steel pile to form a cylindrical enclosure, and filling the inside of this enclosure with concrete.