JP3017676B2 - PC sheet pile and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PC (prestressed concrete) sheet pile used for seawalls and earth retaining walls and a method of manufacturing the same.

[0002]

2. Description of the Related Art Concrete sheet piles, particularly PC (prestressed concrete) sheet piles, have become widespread from the viewpoints of corrosion resistance and durability. . In recent years, the demand for long sheet piles to be driven into soft ground has also been increasing. However, conventional concrete sheet piles can be manufactured up to about 40 m in length, but due to regulations on transportation, they have been reduced to about 21 m. Since the connection of concrete sheet piles is not easy, there is an urgent need to develop technology to solve the problem of long concrete sheet piles.

Conventionally, a method of manufacturing a PC sheet pile has been efficiently manufactured in large quantities by a pretension method. However, there is an inherent problem that a pretension type member cannot introduce prestress near an end portion. This solution was also an issue. In the current market, there is a great demand for large-sized sheet piles for harbors, and there are many inquiries about whether or not concrete sheet piles are to be connected depending on the environment in the city area and road conditions. It is actually necessary.

The length of the PC corrugated sheet pile that can be manufactured is L = 40 m.
Although the sheet pile can be transported to the extent, the sheet pile can be transported according to road conditions, truck conditions, and the like.
It is up to about 0 m. In the driving of steel and steel pipe sheet piles (long sheet piles), a sheet pile of a fixed size that can be transported and driven is carried in and driven in, and the sheet piles are further joined by welding,
Drive the sheet pile. By repeating this, it is possible to drive a long sheet pile.

[0005]

However, it has not been possible to connect PC sheet piles in the past. The reason is as follows. PC sheet piles are manufactured by the pretension method,
Based on the principle that a pre-tensioned PC steel wire is wound with concrete and then the tension of the PC steel wire is relaxed to introduce prestress into the concrete sheet pile by the adhesive force of the concrete, both ends of the sheet pile are connected to the PC steel wire. Since the length of adhesion to the concrete is insufficient and the adhesion is insufficient, the amount of shrinkage of the steel wire penetrates into the concrete and becomes fixed, so that the prestress amount at both end surfaces is reduced to zero. The length Δl at which the amount of prestress is reduced is about 70 times the diameter of the PC steel wire. If a post-tensioned PC sheet pile is used, the PC steel wire is tensioned, and P is applied to the supporting plates at both ends of the concrete sheet pile body.
By fixing the C steel wire, pre-stress can be reliably applied to both end faces of the sheet pile, and the adhesion between the PC steel wire and concrete is performed by grouting the inside of the sheath, which is a drawback of the pretension type sheet pile. The decrease in the amount of prestress near both ends is theoretically eliminated,
In the case of the post-tension type PC sheet pile, there is a problem in driving the sheet pile in construction. Generally, for driving a sheet pile, the sheet pile is driven into the ground by vibrating the sheet pile up and down repeatedly by a vibro hammer or the like and repeatedly punching and punching. However, in the post-tension method, the sheet pile main body concrete and the PC steel wire are adhered by grout, so that the adhesive force is weak and cannot endure high vibration due to driving. Therefore, the post-tension sheet pile is not used at present.

The present invention makes it easy to add concrete sheet piles, solves the problem that prestressing is not introduced to the end of the pretensioned sheet piles, and enables highly efficient production of prestressed concrete sheet piles and a method of manufacturing the same. The purpose is to provide.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a pretension type PC sheet pile made of steel or continuous fiber reinforcement.
The whole of the PC sheet pile is made of a tension member made of a bar having an external thread formed.
The present invention provides a PC sheet pile characterized in that prestress is introduced over a length thereof , and a longitudinal connection metal fitting of the sheet pile is integrally formed at one or both ends in a longitudinal direction of the PC sheet pile. Preferably, a prestress is introduced over the entire length of the sheet pile, and the tendon for introducing the prestress is a bar formed with a male screw made of steel or a continuous fiber reinforcement, and It is easy to introduce prestress over the entire length. Here, the continuous fiber reinforcing material is a general term for a material obtained by binding carbon fiber, glass fiber, aramid fiber, vinylon fiber, or the like with an epoxy resin or the like.

[0008] The longitudinal connection metal fitting is a metal fitting capable of welding and connecting the end face of the concrete sheet pile on site.
It is preferable to use a shape that covers the periphery of the end face of the sheet pile and that can butt-weld the periphery. The pretensioning type PC sheet pile can be manufactured as follows. That is, the longitudinal connection fitting of the sheet pile is attached to the end face frame at one end or both ends in the longitudinal direction of the sheet pile, and a nut fixed to the longitudinal connection fitting as a pressure plate is provided on the tension member,
The tendon release to prior to the introduction of the pre-stress to the concrete, P, characterized in that the nut is fastened
A method for manufacturing a C sheet pile.

[0009]

Embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows an example of a conventional concrete sheet pile. FIG. 2A is a side view, and FIG. 2B is a graph showing the distribution of effective prestress σ _{pe in} the longitudinal direction. The effective prestress is reduced in the portions Δl at both ends of the entire length L of the sheet pile 1. This length Δl is about 70 times the diameter of the tendon 2.
For example, for a 12.7 mmφ PC steel strand, Δl is estimated to be about 890 mm. If a PC sheet pile having a stress distribution as shown in FIG. 2 is spliced, as shown in FIG. 3, the amount of prestress at the joint portion is reduced, and even if a connection metal is attached and connected by welding, The yield strength is reduced, which is a structural problem. Therefore, it has been conventionally impossible to connect a pretension type concrete sheet pile.

In order to cope with the above problem, the PC sheet pile main body is pretensioned in consideration of driving, but in order to prevent a decrease in the amount of prestress at both ends, both ends are made as if by a tension member as in the case of post tension. Is fixed with a nut using a fixing plate, and a narrow diameter PC steel rod is used instead of a conventional PC steel stranded wire as a tendon (in this example, urbon of φ17 mm: trade name of Induction Heating Co., Ltd.) It was used. FIG.
Fig. 1 (a) is a side view of a connected sheet pile, and Fig. 1 (b) is an effective prestress σ _{pe in the} longitudinal direction.
5 is a graph showing the distribution of. When the connection hardware is connected by welding, as shown in FIG. 1B, the effective prestress becomes uniform over the entire length of the connected sheet pile. FIG. 4 is a side view of a PC tendon for achieving this. PC tendon 2
Is longer than the sheet pile block length L by α,
Formed threads are formed at both ends. The appropriate length 5 of each screw is about 250 mm. A nut 6 is screwed into this screw in advance.

As shown in FIG. 5, the PC tendon 2 is inserted into the connection fittings 3 at both ends of the sheet pile on the concrete sheet pile manufacturing form (bottom frame), and the nut 4 is also attached to the outside of the connection fitting 3. . Since the sheet-making bench abutment is a long line, the PC tendon 2 is connected by the coupler 7 and the tension is fixed to the tensioning post of the abutment for one yard by a simultaneous tensioning machine. The simultaneous tensioning machine is a device having a built-in large jack of several hundred tons capable of simultaneously applying a tension to a plurality (5 to 20 or more) of tension members.

After the tensioning operation of the PC tension member, the connection fitting 3
Is set to the sheet pile block length L, and the nuts 6 and 4 inside and outside the connection fitting 3 are tightened and fixed to the connection fitting 3 (see FIG. 6). After assembling the formwork, placing concrete, curing, removing the formwork,
C Tighten the nuts 4 at both ends of the tendon with a wrench.
When the work is completed, the tensile force of the simultaneous tensioner is released and prestress is introduced into the concrete. Since the PC tendon 2 is fixed to the connection fittings 3 at both ends by the nuts 4 and 6, prestress is introduced to the ends. FIG. 7 shows a state in which the terminal of the PC tendon 2 is processed. A compressive force indicated by an arrow 11 is acting on the concrete. In the sheet pile concrete, since the concrete and the PC tendon 2 are bonded by the bonding force at the bonding portion 12, a compressive prestress is introduced into the concrete. At the end of the sheet pile, the connection fitting 3 is pressed against the concrete by the nut 4, and the PC tendon 2 applies a compressive stress 13 (arrow) to the end. In the above description, the nut 6 inside the connection fitting 3 is not necessarily essential, but is preferable in order to perform the work accurately and accurately.

[0013] The PC sheet pile is taken out of the formwork, and the sheet pile is terminated. FIG. 8 shows this, in a state where the nut 4 is embedded in the connection fitting 3,
Filled with 4. FIG. 8B is a front view. FIG.
It is a perspective view which illustrates arrangement of the connection fitting 3 and the reinforcing bar 8. FIG. 10 is a perspective view of the entire sheet pile at the same stage as FIG. 7, and FIG. 11 is an overall perspective view of the same state as FIG. Next, an example of the sheet pile driving construction of the present invention will be described with reference to FIGS. FIG. 12 shows the sheet pile 1 driven into the ground 20 and partially exposed to the ground. FIG.
Shows a process of connecting the next sheet pile 1b to the upper end of the sheet pile 1a already driven into the ground 20 in the state of FIG. A guide plate 21 for receiving and aligning the next sheet pile 1b is attached to the upper side of the sheet pile 1a with bolts 22, and the next sheet pile 1b
Is hung above it with a hanging tool 24 as shown by an arrow 23. FIG. 14 shows a state where the suspension is completed. Next, as shown in FIG. 15, the connection fittings 3 are integrated by a weld joint 26 by welding 25. FIG. 16 is a cross-sectional view of the sheet pile connection portion after welding has been completed, and shows that the upper and lower sheet piles 1a and 1b are structurally integrated.

[0014]

According to the present invention, the problem of loss of prestress near the end of a member peculiar to a prestressed concrete sheet pile conventionally manufactured by a pretensioning method is solved, and a short PC sheet pile is connected to a long sheet pile. High durability PC with uniform pre-stress applied over the entire length
Sheet piles can be supplied. In addition, a large-diameter rod-shaped tendon can be used, and an effect such as reduction in labor for disposing the tendon can be expected.

[Brief description of the drawings]

FIG. 1 is a (a) side view and (b) a graph showing a distribution of effective prestress of a connected concrete sheet pile of an example.

FIG. 2A is a side view of a conventional concrete sheet pile;
(B) A graph showing the distribution of effective prestress.

3 (a) is a side view of a conventional connected concrete sheet pile, and FIG. 3 (b) is a graph showing a distribution of effective prestress.

FIG. 4 is a side view of the tendon member of the embodiment.

FIG. 5 is an explanatory view of a manufacturing process of the embodiment.

FIG. 6 is an explanatory diagram of a manufacturing process of the embodiment.

FIG. 7 is an explanatory diagram of the manufacturing process of the example.

FIG. 8 is an explanatory diagram of the manufacturing process of the example.

FIG. 9 is a perspective view showing an arrangement of connection fittings and reinforcing bars according to the embodiment.

FIG. 10 is a perspective view of the entire sheet pile of the embodiment.

FIG. 11 is a perspective view of the entire sheet pile of the embodiment.

FIG. 12 is an explanatory diagram of a casting process in the embodiment.

FIG. 13 is an explanatory diagram of a casting process in the embodiment.

FIG. 14 is an explanatory diagram of a casting process in the embodiment.

FIG. 15 is an explanatory diagram of a casting process in the embodiment.

FIG. 16 is an explanatory diagram of a casting process in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a, 1b Sheet pile 2 Tension material 3 Connection metal 4 Nut 5 Screw length 6 Nut 7 Coupler 11 Arrow 12 Attachment part 13 Compressive stress (arrow) 14 Resin mortar 20 Underground 21 Guide plate 22 Bolt 23 Arrow 24 Hanging tool 25 welding 26 welding joint

Claims (2)

(57) [Claims] 1. An external thread made of steel or a continuous fiber reinforcement is formed in a pretensioning type PC sheet pile .
Prestressing over the entire length of the PC sheet pile with the tendon of the bar
There is introduced, PC sheet pile in the longitudinal direction of one or both ends of the PC sheet pile sheet pile in the longitudinal fitting is characterized in that it is formed integrally. 2. For the production of a pretensioning type PC sheet pile.
Hit the arrow on the end formwork at one or both ends in the longitudinal direction of the sheet pile.
Attach the longitudinal connection fitting of the plate, and use the longitudinal connection fitting as a support plate.
Then, a nut fixed to this is provided on the tendon, and the tendon is
Before releasing and introducing prestress into the concrete ,
The nut is fastened and fixed to the connection fitting .
Method of manufacturing a P C sheet pile that.