JPH04118116A - Manufacture of drill steel tube pile - Google Patents

Abstract

PURPOSE:To easily manufacture the drill steel tube pile by connecting the short tube welded with the spiral like rib on either of inner surface or outer surface or both surfaces to the top end of the pile body. CONSTITUTION:The spiral like ribs 2, 3 of the inner and outer surfaces are formed preliminarily to the spiral like, inserted into the inner and outer sides of the tube by matching both pitches, then only the weld beginning end parts 4, 5 are welded temporarily. The pressing rollers 13, 14 for pressing the ribs to the tube wall respectively are provided on the outer surface welding device 11 and the inner surface welding device 12. Here, the pressing rollers 13, 14 for applying the pressing force to the ribs are integrally formed with the welding torch, this rollers are used as well the copying device. If the rib welding for the inner and outer surfaces is executed at the same time by moving in the width direction along the tube axis by one pitch per one rotation of the tube, the good weld connection for the rib can be easily executed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing drilled steel pipe piles.

[Prior art] Drilled steel pipe piles have 10 to 20
Bars, etc. (ribs) with a cross-sectional size of approximately 1.0 mm are attached in a spiral shape to facilitate penetration during pile driving and to provide high support capacity as a support pile. Such piles are disclosed, for example, in Japanese Patent Application Laid-Open Nos. 1-127718 and 1-146011.

In addition, in order to attach such ribs to the inner surface of the tube,
The apparatus and method disclosed in Japanese Patent Application Laid-open No. 1-226931 and Japanese Unexamined Patent Publication No. 1-237020 may be used, but long piles are not easy to construct.

Furthermore, when welding ribs to the inner and outer surfaces of such a steel pipe pile, the steel pipe to which the inner and outer ribs are to be welded must be held at one end in a cantilevered manner and rotated. because,
Since external ribs are attached to the entire length of the steel pipe, in the case of a normal turning roller type, the external ribs will hit the roller and prevent normal rotation.

Further, in flare welding of ribs, the ribs are lifted off the tube surface due to welding deformation, and the gap between the tube surface and the ribs widens, making welding impossible. For example, if a gap of 3 mm or more occurs, welding becomes impossible. therefore,
It is necessary to take measures to prevent lifting by pressing the rib against the pipe surface just before the weld. Particularly in the case of the outer surface, the lifting amount is large and pressing requires a force of 100 kg or more.

If both the inner and outer surfaces are welded downward, the weight of the tube and the reaction force of the above pressing force must be borne only by the supporting end (fixed end) at one end of the tube, and the size is 2 to 3 ton-m.
As a result, the fixation of the tube becomes unstable and good welding cannot be achieved.

[Problem to be solved by the invention]

In view of these circumstances, an object of the present invention is to provide a technology that allows easy manufacture of drill steel pipe piles by connecting short pipes provided with spiral ribs to the tip of pile bodies.

In addition, the present invention presses the inner and outer ribs of a drill steel pipe pile with ribs welded on the inner and outer surfaces by guide rollers from the inside and outside of the pipe,
It is an object of the present invention to provide a method for manufacturing a drilled steel pipe pile in which welding is performed in a downward position while a welding torch is moved in conjunction with the welding torch.

Furthermore, we propose a method for attaching the ribbed short pipe manufactured in this manner to a pile body.

[Means for Solving the Problems] The method of the present invention is a method for producing a drilled steel pipe pile, characterized in that a short pipe having spiral ribs welded to one or both of its inner and outer surfaces is connected to the tip of the pile body.

Furthermore, when spiral ribs are welded to the inner and outer surfaces of a drilled steel pipe pile, the steel pipe is held rotatably around the axis, and spiral ribs of the same pitch are attached to the inner and outer surfaces of the steel pipe in phase. The inner and outer ribs are simultaneously pressed against the inner and outer surfaces of the pipe wall at the same position from the inside and outside of the pipe by a pair of opposing pressing guide rollers, and the inner and outer ribs near this pressing part are automatically welded downward. Features.

Furthermore, by manufacturing a short pipe with welded internal and external spiral ribs by this method and connecting this to the tip of the pile body, a long drilled steel pipe pile can be easily manufactured.

In the present invention, the pile body is not limited to a steel pipe, but may also be a PC pile, which can be welded to a bearing plate (PC steel fixing plate) on the end face of the PC pile, and can be referred to as a drilled steel pipe pile in a broad sense.

[Effect 1: A short steel pipe of about 3 to 4 m long with spiral ribs attached to one or both of its inner and outer surfaces in advance and another long pile body (steel pipe, PC pile, etc.) are circumferentially welded and integrated. By manufacturing long basic steel pipe piles (drill piles), desired drill piles can be manufactured more easily than by attaching ribs to long pipes.

In addition, in the present invention, when attaching ribs to the inner and outer surfaces of the steel pipe,
By balancing the rib-like pressing force by applying it to the same position on the steel pipe from the inside and outside of the pipe, the burden on the pipe holding force that holds one end is reduced, the pipe is held stably, and good welding is achieved. It can be performed.

[Example] Fig. 1 is an explanatory diagram of a case where ribs are attached to the inner and outer surfaces of an example of the method of the present invention.

A description will be given based on an example in which a rib 2 is welded to a steel pipe 1 measuring $318 mm x 9 mm t x 3 m12 in length along the entire length on the outer surface, and a rib 3 for 1.5 m from one end on the inner surface. ribs 2, 3
A round bar with a diameter of 13 mm was formed into a spiral shape with a pitch of 300 mm. The steel pipe 1 is held in the form of a cantilever with one end fixed to a rotating jig 10, and as shown by arrows 17 and 18, the steel pipe 1 rotates around the axis along with the rotating jig 10, and rotates by 300 mm per rotation (one helix). pitch) horizontally in the direction of the tube axis.

In order to obtain a good bead in flare welding, the welding posture is from downward to horizontal.If this is divided into the outer and inner surfaces, the outer surface is from 9 o'clock on the clock face as shown in Figure 2 (a). The range 21 at 13 o'clock is the range 21 from 5 o'clock to 9 o'clock on the inner surface as shown in FIG. 2(b).

From this, the welding position when simultaneously welding the inner and outer surfaces is an area 23.24 of about 100 mm centered on the horizontal royal road (9 o'clock) position where both overlap.

The external welding device 11 is mounted on a gate-shaped frame (not shown) that stands on the side of the pipe, and the internal welding device 12 is mounted on a gate-shaped frame (not shown) with a diameter of $200 mm.
Each was fixed to the free end of a horizontally fixed arm (one end fixed, not shown) having a length of 9 mm and a length of 3.5 m.

The spiral ribs 2 and 3 on the inner and outer surfaces were previously formed into a spiral shape, and after inserting them into the inside and outside of the tube with their pitches matched, only the welding start end 4.5 was temporarily attached.

External welding device 11. The internal welding device 12 is equipped with rollers 13 and 14 for pressing the ribs against the pipe wall.

For pressing, a pressing force is applied to the rollers 13 and 14 by an air jack.

For pressing, the rollers 13 and 14 were set approximately 100 mm ahead of the welding torch 15° 16, and for pressing with an air jack, the air pressure of the air jack was adjusted so that the force was 100 kg on both the inner and outer surfaces, and then gas shield welding was started.

When pressing the rib, use a roller just before the welding position.
As shown in Figure 1, the inner and outer surfaces are in the same position. Here, the holding stability of the tube is increased by pressing the inner and outer surfaces by applying forces p(,,pl) in opposite directions and the same, or by increasing Pi by the weight of the tube.

Here, the pressing roller that applies force to the rib is integrated with the welding torch, and this roller also serves as a copying device. If the tube is moved laterally along the tube axis by one pitch per rotation and the ribs are welded on the inner and outer surfaces at the same time, good rib welding can be easily achieved.

The vertical movement of the steel pipe 1 during welding was suppressed to about 1 mm, and good flare welding of the ribs 2 and 3 was achieved.

[Effects of the Invention] According to the present invention, a short pipe in which spiral ribs are welded to one or both of the inner and outer surfaces of the short pipe is connected to the tip of the pile body, so a drilled steel pipe pile can be easily manufactured. . Further, by the method of the present invention, inner and outer ribs can be efficiently welded to the inner and outer surfaces of the short pipe with high quality, and the present invention greatly contributes to reducing the manufacturing cost of the entire steel pipe pile.

[Brief explanation of drawings]

FIG. 1(a) is a vertical cross-sectional view of a pile showing an example for explaining the method of the present invention, FIG. 1(b) is a cross-sectional view thereof, and FIG. 2(a)
, (b) are explanatory diagrams of welding positions. 1...Steel pipe 2...Outer rib 3...Inner rib 4.5...Welding start end 10...Mounting device 11.12...Welding device 13.14...Pushing by roller

Claims (1)

[Claims] 1. A method for manufacturing a drill steel pipe pile, which comprises connecting a short pipe with spiral ribs welded to either or both of the inner and outer surfaces to the tip of the pile body. 2. When attaching spiral ribs to the inner and outer surfaces of a drilled steel pipe pile by welding, one end of the steel pipe is held rotatably around the axis, and spiral ribs with the same pitch are wound around the inner and outer surfaces of the steel pipe in the same phase. A method for producing a drilled steel pipe pile, characterized in that the inner and outer ribs are pressed against the inner and outer surfaces of the tube wall at the same position by a pair of opposing inner and outer pressing guide rollers, and the inner and outer ribs near the pressed portions are automatically welded downward. 3. A method for manufacturing a drilled steel pipe pile, which comprises connecting a short pipe with spiral ribs welded by the method according to claim 2 to the tip of the pile body.