JPS62153414A - Reinforcing work for steel sheet pile - Google Patents

Abstract

PURPOSE:To reinforce steel sheet piles by attaching a prestressed steel material to the quaywall of steel sheet piles. CONSTITUTION:On a quaywall formed by driving steel sheet piles 11, fixing metals 23 are fixed to near the bottom under water and also to near the upper end of a steel sheet pile 11. A prestressed steel material 27 is tensely attached between the fixing metals 23. A stress is generated against the pressure of earth which is applied to the back side of the steel sheet pile 11. Reinforcing the steel sheet pile 11 in such a way as to balance stresses during the newly setting period can be made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for reinforcing steel sheet piles in a quay using steel sheet piles.

(Prior Art) In a quay wall using steel sheet piles, most of the front surface of the driven steel sheet piles that protrudes above the water bottom is constantly in contact with seawater, etc. Therefore, as the front surface of the steel sheet pile is exposed to seawater or the like for a long period of time, corrosion progresses and the section modulus decreases, and accordingly, the resistance of the rear surface of the steel sheet pile to the earthen wall also decreases.

This corrosion on the front surface of the steel sheet pile is particularly severe near the water surface where the concentration of dissolved oxygen in the water is high. If the resistance of steel sheet piles to the soil is reduced, the stress balance state at the time of new construction will change, and the service life of the quay walls will be significantly shortened.

Conventionally, the resistance of steel sheet piles has been increased by welding reinforcing iron plates, reinforcing with reinforced concrete, etc. in the splash zone where the wall thickness has significantly decreased due to corrosion.

(Problems to be Solved by the Invention) However, although it is possible to increase the resistance of the steel sheet piles with this conventional reinforcement method, the resistance to the back of the steel sheet piles decreases as corrosion progresses. If the stress equilibrium state changes.

It was extremely difficult to return to the stress equilibrium state at the time of new construction.

The present invention has been made with attention to these points, and aims to generate stress that opposes the tosho using the tension of prestressed steel materials, and to reinforce the steel sheet piles so that the stress will be balanced when newly installed. .

(Means for Solving the Problems) Therefore, in the steel sheet pile reinforcement method according to the present invention, first, the corrosion of the front surface of the portion of the steel sheet pile that is driven above the water bottom that is driven in for earth retaining of the quay wall is We repaired the parts where the steel sheet piles are particularly severe so that they would not buckle even if prestressing was applied, and then installed fixing fittings by welding, etc., near the upper and lower ends of the front of the parts of the steel sheet pile that protrude above the water bottom. Fix it.

Furthermore, a prestressed steel material is attached between the re-fixing fittings to tension the prestressed steel material.

(Function) In the reinforcing method for steel sheet piles of the present invention, the corroded portions on the front surface of the steel sheet piles are repaired to increase the resistance of the steel sheet piles, and the areas near the upper and lower ends of the front surface of the steel sheet piles are repaired. A prestressed steel material is installed between the fixing metal fittings fixed to the steel sheet pile, and the tension applied to this steel material generates stress that counteracts the stress applied to the rear surface of the steel sheet pile. This made reinforcement possible.

(Example) Next, an example of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional side view of a quay for explaining one embodiment of the steel sheet pile reinforcement method according to the present invention, FIG. 2 is a perspective view thereof, and FIG. 3 is a partial plan view thereof. In the drawings, 11
is a number of steel sheet piles that are connected to each other and are cast on the seabed 13 to secure the quay wall. Earth pressure 17 from the earth and sand on the quay is added. In the sea surface portion of the steel sheet pile 11, as described above, the amount of dissolved oxygen in the seawater 15 is large, and corrosion progresses rapidly. 19 is the sea level, 19a is at high tide, and 19b is at low tide.

For steel sheet piles 11 whose section modulus has decreased due to corrosion and whose resistance to earthen walls has decreased, first, the portions where corrosion has progressed significantly are repaired. To do this, rust etc. are removed from the corroded portion of the front surface of the steel sheet pile 11, and a reinforcing iron plate 21 is applied to the corroded portion and welded.

In the drawing, this reinforcing iron plate 21 is welded near the sea surface where corrosion is severe. Next, fixing fittings 23 are fixed by welding to the vicinity of the upper end and the vicinity of the lower end of the portion of the front surface of the repaired steel sheet pile 11 that protrudes above the seabed 13, respectively. That is, the fixing fittings 23 near the upper end are welded onto the reinforcing iron plate 21, and the fixing fittings 23 near the lower end are directly welded to the front surface of the steel sheet pile 11. This fixture 23 has a groove 25 having a U-shaped cross section, and is welded and fixed to the steel sheet pile 11 so that the groove 25 is aligned substantially in a straight line.

Next, one prestressed steel member 27 is attached between the re-fixing fittings 23 fixed to the steel sheet pile 11. The prestressed steel material 27 is attached by fitting the end of the prestressed steel material 27 into the groove 25 of the re-fixing fitting 23. Next, tension is applied to the prestressed steel material 27 by pulling it with a jack or the like. The tension in the prestressed steel material 27 is fixed by tightening the nuts 29 screwed onto both ends of the prestressed steel material 27, and is transmitted to the steel sheet pile 11. Therefore, when the prestressed steel material 27 is in a tensed state, a force that bends the steel sheet pile 11 as shown by the two-dot chain line X in FIG.

(Effects of the Invention) The present invention is configured as described above, and increases the resistance of the steel sheet pile by repairing the portion where corrosion has progressed significantly on the front surface of the steel sheet pile. Fixing metal fittings are fixed near the upper and lower ends of the front surface of the section, and a prestressed steel material is attached between them and tension is applied to this to generate stress that counteracts the soil stress applied to the rear surface of the steel sheet pile. Therefore, it is possible to achieve the excellent effect of reinforcing the steel sheet pile so that it will be in a stress-balanced state when newly installed.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional side view of a quay wall for explaining an example of the implementation of the steel sheet pile reinforcement method according to the present invention, FIG. 2 is a partial perspective view thereof, and FIG. 3 is a plan view of the main part thereof. 11...Steel sheet pile, 21...Reinforcement iron plate, 23...Fixing metal fittings. 27...Prestressed steel material. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) In a method for reinforcing steel sheet piles on quay walls where earth retaining is done by driving steel sheet piles, repairing the corroded part on the front of the part of the driven steel sheet piles that protrudes above the water bottom; Next, fixing fittings are fixed to the vicinity of the upper end and the vicinity of the lower end of the front surface of the portion of the driven steel sheet pile that protrudes above the water bottom,
Next, a prestressed steel material is attached between both of the fixing metal fittings, and the prestressed steel material is tensioned.