JP4544618B2 - Deformed bar with groove and its pile head joint structure and construction method - Google Patents

Description

The present invention relates to a deformed steel bar with a groove, a pile head joint structure thereof, and a construction method.

Deformed steel bars have been used in the form of only nodes and ribs for several decades, but with remarkable progress in peripheral technology, not only the adhesion performance with concrete but also the welding performance with steel materials etc. is required Therefore, in order to improve weldability, the steel pipe pile and the concrete pile wound with the steel pipe and the foundation slab constructed on the upper part of the deformed steel bar are secondary processed by forging etc. in a separate process. It is used for joining.

However, the conventional technique has the following problems.

The deformed steel bar has only protrusions such as joints and ribs formed on the surface, and the adhesion performance with the specified concrete is ensured, but the joints cause irregular and excessive root gaps on the weld surface during welding with the steel pipe. Therefore, it has a defect in the accuracy of the welded portion and the shape of the welded portion, and is treated as a steel bar that is not suitable for welding that may cause a defective welded portion.

In order to improve the weldability of deformed bar steel, the secondary processing of forming a groove in a part of the deformed bar steel in a separate process by forging etc., the general shape of the deformed bar steel used for pile head joining is 1.4 ~ Since it is 1.7 m and the weight is 9 to 16 kg / piece and it is long and heavy, it is difficult to automate, and each piece is a manual operation, requiring a great amount of machining cost and time.

The secondary work material in which a forged groove is formed on a part of a deformed steel bar or a metal fitting with a groove formed by friction welding is heated to 1000 ° C. or more by upset processing and frictional heat. The mechanical properties of deformed steel bars that were uniform over the entire length were remarkably reduced in part, as confirmed by the microstructure and Charpy impact test, etc. , It is vulnerable to impact at the processing boundary and has a risk of brittle fracture. In addition, since the cross-sectional shape and the arrangement of the nodes are different between the deformed steel bar part and the processed part, it is not possible to expect uniform adhesion.

A groove of a certain length formed on a part of a deformed steel bar cannot cope with a change in the weld length due to the design of the weld, the difference in weld strength due to the material of the steel pipe, and the reason for welding work.

The method of welding the steel bar to the side of the pile head varies depending on the shape of the deformed steel bar, but an out-of-plane bending moment due to eccentricity is always generated in the welded part of the steel pipe and steel bar, and the joining material is pulled. In addition to not being able to fully demonstrate the performance, the steel pipe may be bent and broken outside, or the foundation slab on the side of the pile head may be broken.

Since the welding of the deformed bar with groove and the side surface of the steel pipe takes a vertical welding position, the weld outer end at the lower end of the deformed bar with groove cannot be completely welded.

In this invention, the said problem is solved by having developed the deformed steel bar with a groove | channel, its pile head joining structure, and a construction method.
As a deformed steel bar with a groove welded to the steel side, the surface that contacts the steel side is the surface formed in the longitudinal direction of the steel bar, and the J-shaped or lathe groove on both sides of the contacting surface is the longitudinal direction of the steel bar. Further, a groove having a predetermined length in the longitudinal direction and a node extending over the entire length in the longitudinal direction except for the J-shaped or lathe-shaped groove on the same circumferential surface is provided on the circumferential surface of the steel bar. Irregular shaped bar steel , or a deformed steel bar with a groove formed into a groove having the above-described configuration, and a J-shaped or a lath-shaped groove provided on the steel bar and the node are uniformly roll-formed. Propose what you have formed.
The surface in contact with the steel material side surface is a surface formed in the longitudinal direction of the steel bar.
As a joining structure of a pile and a foundation slab, in the joining of a steel pipe pile or a concrete pile wound with a steel pipe and a foundation slab constructed on the upper part, the above-mentioned deformed bar steel with a groove is placed on the side of the steel pipe of the pile. We propose a joint structure between a pile and a foundation slab, characterized in that a large number of pipes are welded in an upright position by bringing the surface formed in the longitudinal direction of the steel bar into contact.
In addition, in welding the deformed steel bar with a groove described above and a steel pipe pile or a steel pipe side surface of a concrete pile wound with a steel pipe, the steel pipe side surface of the pile had a width that covers the groove of the deformed bar steel with the groove. A ring-shaped hardware is welded, and the lower end of the deformed bar with groove is brought into contact with the upper end of the ring-shaped hardware, and the surface formed in the longitudinal direction of the deformed bar with groove at the side of the steel pipe of the pile. A construction method is also proposed in which a large number of deformed bars with grooves are welded to the side surface of the steel pipe in contact with each other.

The deformed steel bar with groove and the pile head joint structure and construction method according to the present invention have the following specific effects.

Since the groove that meets the joints and welding standards can be uniformly and accurately formed on the same circumferential surface of the steel bar and at predetermined intervals in the longitudinal direction of the steel bar, highly reliable welding and the overall length of the steel bar It is possible to develop a uniform adhesive force over the entire area.

By setting the groove roll to the hole shape of the deformed steel bar roll, material is passed between the rotating rolls, reducing the cross-section and making a deformed steel bar with a groove and a groove in one step. Because it can be molded by, significant improvement in production efficiency and cost reduction are achieved.

High mechanical properties rich in toughness, consisting of a uniform and dense structure over the entire length inherent to steel materials, can be obtained.

Since the groove is formed uniformly in the longitudinal direction of the steel bar, all changes in the weld length due to the weld design, differences in weld strength due to the material of the steel pipe, and reasons for welding work must be supported. I can do it.

Ring-shaped hardware welded to the side of a steel pipe can handle the out-of-plane bending moment associated with the eccentricity of the steel pipe and the steel bar as the tensile force in the circumferential direction of the hardware. Without generating an external bending moment, it is possible to prevent the deterioration of the performance of the joint material due to the eccentric bending moment and the destruction of the steel pipe and the surrounding foundation slab.

The ring-shaped hardware welded to the side of the steel pipe can also function as an end tab, so even in a vertical welding position, the welded part from the weld outer end to the upper end of the lower end of the deformed steel bar with a groove is surely secured. It is possible to weld to.

Here, an embodiment of the deformed steel bar with groove, the pile head joint structure and construction method of the present invention will be described with reference to the drawings.

FIG. 1 is an elevational view of a deformed steel bar 6 with a groove according to the inventions of claims 1, 2 and 3. The deformed steel bar 6 with a groove shows an example of a configuration in which a node 7, a J-shaped groove 8 and a rib 9 are continuously formed over the entire length, but by changing the shape and pitch of the groove dug into the roll, the node 7 and the groove 8 can be intermittently roll-formed at predetermined intervals in the longitudinal direction of the steel bar. An example in which the joints 7 are arranged parallel to the circumferential direction and the ribs 9 are arranged on both sides in the longitudinal direction are shown. However, any shape and number that are regular and uniform can be formed. It is.

FIG. 2 is a detailed cross-sectional view of a deformed steel bar 6 with a groove, taken along line BB in FIG. The J-shaped groove 8 is a groove shape similar to the letter J in combination with a straight line and an arc in a cross-sectional view of the deformed steel bar 6 with a groove, and in a side view is a surface continuing in the longitudinal direction provided on both sides of the steel bar. It is a certain groove .
A J-shaped groove 8 of the deformed steel bar 6 with a groove is provided on both sides of the steel bar, and the J-shaped groove 8 is formed as a surface continuing in the longitudinal direction.
Between the J-shaped groove 8 and the J-shaped groove 8 is a surface formed in the longitudinal direction so as to contact the steel pipe 2.
The shape of the J-shaped groove 8 can also be selected.
In general, the groove should be finished smoothly in order to improve the penetration of the weld metal, but for reasons such as manufacturing, the surface of the J-shaped groove 8 is within the tolerance of the groove dimension of about 1.0 mm. Sometimes it is processed with unevenness.

FIG. 3 is an elevational view of the deformed steel bar 6 with a groove, taken along line C in FIG. Between the groove 8 and the groove 8 is a surface 11 formed so as to come into contact with the steel pipe 2, and in this embodiment, an example in which the node 7 and the depression 10 are formed intermittently in the longitudinal direction is shown. Depending on the adhesion performance, the nodes 7 may be formed continuously, or the surfaces without the nodes 7 may be formed.
In order to form the node 7 and the recess 10 without projecting from the surface 11 in contact with the steel pipe 2, the hole mold of the surface 11 is previously projected by the height of the node 7, and then the node 7 is molded. The groove to be formed is dug down to the position of the surface 11 in a hole shape.

FIG. 4 is a plan view showing a state in which the deformed steel bar 6 with a groove is attached to the side surface of the steel pipe 2 of the steel pipe pile 1.
The steel pipe pile 1 is composed of an outer steel pipe 2, a ring-shaped hardware 12 welded to the side surface of the steel pipe 2, and a concrete 3 placed inside, and the deformed bar steel 6 with a groove is even on the side surface of the outer steel pipe 2. 6 shows an example of welding six pieces.
The ring-shaped hardware 12 has a width that covers the groove of the deformed steel bar with the groove.

FIG. 5 is a longitudinal sectional view taken along the line AA in FIG. 4, and the deformed bar steel 6 with a groove is formed on the upper end of a ring-shaped metal piece 12 welded to the side surface of the steel pipe 2. An example of a state in which a large number of deformed steel bars 6 with a groove are welded to the side surface of the steel pipe 2 of the pile 1 is shown. In addition to the present embodiment, the deformed bar steel 6 with a groove can be applied to welding with any steel material such as welding with a shape steel such as an H shape and welding between the deformed bar steels 6 with a groove.

FIG. 1 is an elevational view of a deformed steel bar with a groove according to the first, second and third aspects of the invention. FIG. 2 is a detailed cross-sectional view of a deformed steel bar with a groove, taken along line BB in FIG. FIG. 3 is an elevation view of a deformed steel bar with a groove, taken along line C in FIG. FIG. 4 is a plan view showing a state in which the deformed steel bar 6 with a groove is attached to the side surface of the steel pipe 2 of the steel pipe pile 1. FIG. 5 is a longitudinal sectional view taken along line AA of FIG.

1 Steel pipe pile 2 Steel pipe 3 Concrete in steel pipe pile 4 Foundation slab 5 Welded part of pile and deformed steel bar with groove 6 Deformed bar steel with groove 7 Node 8 provided in deformed steel bar with groove The provided J-shaped groove 9 The rib 10 provided in the deformed steel bar with the groove 10 The recess 11 between the nodes provided in the deformed steel bar with the groove 11 The surface in contact with the steel pipe between the groove and the groove ( The surface formed in the longitudinal direction of the steel bar)
12 Ring-shaped hardware attached to the side of the steel pipe

Claims (3)

In a deformed steel bar with a groove welded to the side of the steel material, the surface that contacts the steel material side is the surface formed in the longitudinal direction of the steel bar, and the J-shaped or lathe-shaped groove on both sides of the contacting surface is in the longitudinal direction of the steel bar. With a groove that is processed over the entire length and further provided with a node extending in the longitudinal direction at a predetermined interval in the longitudinal direction except for the J-shaped or ledge-shaped groove on the same circumferential surface of the steel bar A deformed steel bar , or a deformed steel bar with a groove that has been processed with irregularities in the groove of the above-described configuration, and formed by uniformly roll-molding the J-shaped or lathe-shaped groove and the knot provided on the steel bar A deformed steel bar with a groove , characterized by In joining a steel pipe pile or a concrete pile wound with a steel pipe and a foundation slab constructed on the upper part of the steel pipe pile, the deformed steel bar with a groove according to claim 1 is placed on the side surface of the steel pipe of the pile in the longitudinal direction of the steel bar with the groove molded in contact surfaces, joining structure between piles and the base slab, characterized in that you have large number of welding attitude of TatsuMuko. In welding the deformed steel bar with a groove according to claim 1 and a steel pipe side surface of a steel pipe pile or a concrete pile wound with a steel pipe, the steel pipe side surface of the pile has a width that covers the groove of the deformed steel bar with the groove. A ring-shaped hardware is welded, and the lower end of the deformed bar with groove is brought into contact with the upper end of the ring-shaped hardware, and the surface formed in the longitudinal direction of the deformed bar with groove at the side of the steel pipe of the pile. A construction method characterized in that a large number of deformed steel bars with grooves are welded to the side surface of the steel pipe in contact with each other .

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