JPH0417252B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for preventing corrosion of steel pipe piles.

(Prior Art) Steel pipe piles are widely used as offshore structures, but steel pipe piles are extremely susceptible to corrosion in splash zones and tidal zones.

For this reason, conventionally, the surface of the steel pipe pile is generally covered with a synthetic resin cover reinforced with glass fiber, and the gap between the steel pipe pile and the cover is filled with mortar.

(Problems to be Solved by the Invention) However, since the surface of the cover is smooth, it cannot be expected to have much integrity with the mortar filled between the cover and the steel pipe pile.

Additionally, the head of the cover is fixed to the stake, but it may deteriorate over time and the cover may separate from the mortar.

In addition, if a part of the cover is damaged, the integrity of the cover and internal mortar cannot be expected, so the damage area of the cover will expand, and at the same time, seawater and air will flow around the entire circumference from the gap between the cover and the mortar. The corrosion protection effect of mortar may be significantly reduced.

(Means for Solving the Problems) The present invention has been proposed to solve these problems, and the inner circumferential surface is provided with longitudinal protrusions at predetermined intervals. A semi-hard plastic in which a spacer protruding toward the inner circumferential surface is fitted into the ridge, and a bottom seal is disposed at the bottom that extends diagonally upward toward the center and has an annular groove on the outer circumferential surface. A cap made of a sheet is fitted onto the head of the steel pipe pile, and a ring is pressed down into the gap between the steel pipe pile and the cap, separated by the spacer, so that the annular groove of the bottom seal and the inner circumferential surface of the cap are connected to each other. A method for preventing corrosion of steel pipe piles, characterized in that a bottom seal is pressed onto the outer circumferential surface of the steel pipe pile by press-fitting between the caps, and then the gap between the outer circumferential surface of the steel pipe pile and the inner circumferential surface of the cap is filled with mortar. This is related.

(Function) Since the present invention is configured as described above,
When the cap made of semi-rigid plastic sheet is fitted onto the head of the steel pipe pile, a space is created between the cap and the steel pipe pile by spacers fitted to the ridges arranged in rows on the inner peripheral surface of the cap. is formatted.

Next, when the ring is pressed down into this gap, the ring is press-fitted between the annular groove provided on the outer peripheral surface of the bottom seal of the cap and the inner surface of the cap, and is tilted toward the inner center of the cap. The bottom seal extending upward is deformed toward the inner center by the annular ring, and its tip is pressed against the outer peripheral surface of the steel pipe pile, sealing the lower end of the gap between the steel pipe pile and the cap. When the gap is filled with mortar in this state, the mortar is integrated with the cap via the ridges and protects the steel pipe pile from corrosion.

(Effect of the invention) According to the present invention, the corrosion-preventing mortar filled in the gap between the steel pipe pile and the cap is integrated by the ridges arranged in rows on the inner peripheral surface of the cap, and the steel pipe pile The durability is significantly improved.

In addition, when a steel pipe pile is damaged due to waves, collisions with drifting objects, etc., the damage can be suppressed to a localized area by the ridges on the inner circumferential surface of the cap, and the ridges can be used in areas other than the damaged area. This function prevents the cap from peeling off from the corrosion-resistant mortar, making it possible to perform partial repairs.

In addition, the cap requires a spacer to make the mortar thickness uniform in the circumferential direction, but by fitting this spacer into the protrusion, it is possible to place the mortar at any position on the cap. Spacers can be attached to form any desired cover.

Furthermore, a seal is attached to the bottom of the cap to prevent the mortar filling the gap between the cap and the steel pipe pile from flowing out, but the head of the steel pipe pile is generally fitted with a seal to prevent damage when the pile penetrates. Since a reinforcing band is wrapped around the outer periphery, the seal provides a certain amount of clearance between the cap and the outer surface of the steel pipe pile while the cap is fitted onto the steel pipe pile and lowered to the specified position. The seal must be crimped to the steel pipe pile once the pipe has been lowered to this point.

In the present invention, the bottom seal is disposed so as to face toward the inner center and extend obliquely upward, and an annular groove is provided on the outer peripheral surface, so that the tip of the bottom seal and the steel pipe pile are connected while lowering the cap. so that there is a gap between them so that the cap can be lowered smoothly,
When the cap has been lowered to a predetermined position, the ring is lowered into the gap formed by the spacer between the cap and the steel pipe pile, and the ring is moved between the inner peripheral surface of the cap and the bottom seal. The seal is pressed onto the steel pipe pile by being press-fitted between the cap and the cap, sealing the bottom of the gap between the steel pipe pile and the cap, and reliably preventing leakage of mortar from the bottom of the gap. .

(Example) The present invention will be described below with reference to the illustrated embodiments.

Reference numeral 1 denotes a semi-rigid plastic sheet on which protruding stripes 2 having a T-shaped cross section are arranged at predetermined intervals, and is cut into a required size according to the pile diameter and coverage area.

Next, the waiting portions 3a provided at the base ends of both legs of the V-shaped spacer 3 are fitted into the ridges 2, moved along the ridges 2 to a predetermined position, and then fixed with adhesive.

Next, the sheet 1 is processed into a cylindrical shape so that the protruding stripes 2 are positioned vertically on the inner surface, and a reinforcing band 5 with a bottom seal 4 is wrapped around the outer peripheral surface of the bottom portion and fixed with adhesive to form a cap A. Configure.

A horizontal piece 5a extends from the lower edge of the reinforcing band 5 toward the inner center, and a bent piece 5b extends obliquely upward from the tip of the horizontal piece 5a toward the inner center. ing.

A bottom seal 4 made of synthetic rubber or the like is mounted on the horizontal piece 5a and extends obliquely upward toward the inner center, and an annular groove 4a is provided on the lower outer peripheral surface of the seal 4. It is being

Then, a reinforcing band a is attached to the outer periphery of the cap A according to the internal pressure, and the cap A is inserted from the head of the already driven steel pipe pile B to a predetermined position. At this time, since a gap is provided between the tip of the bottom seal 4 and the steel pipe pile B, the bottom seal 4 does not interfere with the smooth insertion of the cap A.

The spacer 3 connects the cap A and the steel pipe pile B.
By lowering the ring 6 into the gap formed between the bottom seal 4 and fitting it into the annular groove 4a of the bottom seal 4, the bottom seal 4 is deformed as shown by the dotted line in FIG. The tip of the sheet 4 is pressed onto the steel pipe pile B, and the bottom of the gap between the cap A and the steel pipe pile B is sealed.

A plurality of fixing fittings 7 are welded to the outer peripheral surface of the head of the steel pipe pile B, and an inverted L-shaped locking piece 9 attached to the upper end of the L-shaped hanging fitting 8 is locked to the fixing fittings 7, and
The lower end bent portion 8a of the L-shaped hanger 8 supports the horizontal piece 5a of the bottom reinforcing band 5, and supports the cap A. In the figure, reference numeral 10 indicates a nut for adjusting the lifting height of the cap A, which is screwed onto the L-shaped hanging fitting 8.

Next, the gap between the steel pipe pile B and the cap A is filled with mortar C.

After the mortar C has hardened, the hanging fitting 8 is removed and reused.

Since the illustrated embodiment is constructed as described above, the mortar C filled in the gap between the steel pipe pile B and the cap A protects the steel pipe pile B from corrosion, increasing its service life. The mortar C is integrated with the cap A by the ridges 2 arranged on the inner peripheral surface of the cap A, and when the steel pipe pile B is damaged by external force, the mortar C is As a result, damage can be suppressed locally, and the ridges 2 prevent the cap A and the corrosion-resistant mortar C from peeling off in areas other than the damaged area, making it possible to perform partial repairs, and to repair the cap. Since the spacer 3 is fitted to the cap A using the protruding ridge 2, the spacer 3 can be attached to any position on the cap 4 with any desired cover.

Furthermore, in the present invention, the bottom seal 4 is provided at the bottom of the cap A and is arranged so as to extend diagonally upward toward the inner center of the cap. While lowering the cap A to a predetermined position along the An annular concave groove 4 is formed on the outer peripheral surface of the bottom seal 4 by lowering a circular ring 6 into the gap between A and the pile body.
a and the inner circumferential surface of the cap A, the seal 4 is elastically deformed inward, and its tip is crimped to the steel pipe pile B, and the bottom between the pile B and the cap A is Corrosion-resistant mortar C that seals and fills between the two
This is to prevent leakage.

Although the present invention has been described above with reference to embodiments, the present invention is, of course, not limited to such embodiments, and can be modified in various ways without departing from the spirit of the present invention. .

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing the implementation status of one embodiment of the steel pipe pile corrosion prevention method according to the present invention, Fig. 2 is an enlarged plan view showing details of the part in Fig. 1, and Fig. 3 is the bottom seal thereof. FIG. 4 is a vertical cross-sectional view of the left half of a steel pipe pile protected by the method of the present invention, FIG. 5 is a cross-sectional plan view thereof, and FIG. 6 is a semi-rigid plastic sheet. FIG. 7 is a perspective view of the spacer mounting portion. A...Cap, B...Steel pipe pile, C...Corrosion-resistant mortar, 1...Semi-rigid plastic sheet, 2
... protruding ridge, 3 ... spacer, 4 ... bottom seal, 4a ... annular groove, 6 ... circular ring.

Claims (1)

[Claims] 1. On the inner peripheral surface, longitudinal protruding stripes are arranged at predetermined intervals, spacers protruding toward the inner circumferential surface are fitted to the protruding stripes, and spacers are fitted to the bottom of the longitudinal protruding strips at predetermined intervals. A cap made of a semi-rigid plastic sheet, which extends obliquely upward and is provided with a bottom seal having an annular groove on the outer circumferential surface, is fitted onto the head of the steel pipe pile, and is separated through the spacer to connect the steel pipe pile and the cap. The ring is pressed down into the gap between the annular groove of the bottom seal and the inner peripheral surface of the cap to press the bottom seal to the outer peripheral surface of the steel pipe pile, and then the outer peripheral surface of the steel pipe pile and the cap are pressed together. A corrosion prevention method for steel pipe piles characterized by filling the gap between the cap and the inner peripheral surface with mortar.