JP4687327B2 - Press straightening method for U-shaped steel sheet pile with arms - Google Patents

Description

  The present invention relates to a press correction method for a U-shaped steel sheet pile having an arm portion between a flange portion and a joint portion, and particularly to a method suitable for correcting the arm portion.

  Steel sheet piles manufactured by rolling may have shape defects such as vertical warping and horizontal bending due to factors such as vertical and horizontal asymmetry in the rolling process and vertical and horizontal temperature deviations. In particular, bending and warping at the joint portion impairs the joining (fitting) for making the wall body, which is a big problem in the installation work.

  FIG. 8 is a view for explaining “upward warping”, and shows a state in which a U-shaped steel sheet pile 100 having an arm portion is warped to the web 200 side. FIG. 9 is a diagram for explaining “bending”, and shows a state in which a U-shaped steel sheet pile 100 having an arm portion has a rightward bend of δ at the joint portion with respect to the longitudinal direction.

  When warping occurs in actual operation, use a roller straightening machine with multiple upper and lower rolls arranged in a staggered pattern, and correct the size to within tolerance, while if bending occurs In general, correction is performed using a press straightening machine so that the size thereof is within tolerance.

  Bend correction with a press straightener is performed by fixing either the left or right mold (restraint mold) according to the bending direction, and using the other mold (pressing mold) with the flange of the U-shaped steel sheet pile as the material to be corrected. Press repeatedly.

  FIGS. 10A and 10B are diagrams for explaining a bending correction method using a press straightening machine. A U-shaped steel sheet pile 100 having arms is placed on a table roll 80 in a U-shape, and one flange 300 is provided. The holding mold 60 is disposed on the outer surface 300b side, and the pressing mold 70 is disposed on the outer surface 300b side of the other flange 300 (FIG. 10B).

  The holding mold 60 and the pressing mold 70 are arranged so that the three-point bending is caused by the pressing force a applied by the pressing mold 70 (FIG. 10A).

  However, among the U-shaped steel sheet piles, in the case of a steel sheet pile having a large cross-sectional shape and a large rigidity in bending in the left-right direction, even if the flange outer surface on one side is pressed with a press, the bending is not corrected, the cross-sectional shape is deformed, Problems such as local depression of the pressed flange occurred, and this was particularly noticeable in bending correction of a U-shaped steel sheet pile having an arm portion between the flange and the joint portion.

  Patent Document 1 relates to a press correction method for a U-shaped steel sheet pile, and describes a method of correcting the bending by pressing the outer surface of the flange on one side of the steel sheet pile and simultaneously pressing the inner surface of the other flange.

  In FIG. 11, the holding mold 60 is pressed against the outer surface 300 b of one flange 300 of the U-shaped steel sheet pile 100 having an arm portion, which is placed in a U shape on the transport roll 80, and pressed against the outer surface 300 b of the other flange 300. The pressing mold 70 is disposed on the inner surface 300a side of the flange 300 on which the mold 70 is disposed and the holding mold 60 is disposed.

  The holding mold 60 and the pressing mold 70 are arranged such that the U-shaped steel sheet pile 100 having the arm portion is bent at three points by the pressing force a applied to the pressing mold 70.

Since the pressing force a by the pressing mold 70 is applied to the left and right flanges 300 in the same direction from the inner surface 300a side to the one side and from the outer surface 300b side to the other side, the cross-sectional shape of the U-shaped steel sheet pile 100 is impaired. It is possible to correct the bend.
Japanese Patent No. 3129179

  However, since the correction method described in Patent Document 1 presses one flange inner surface and the other flange outer surface of the left and right flanges at the same time, two correction jigs are required. It was not always an efficient correction method.

  On the other hand, a U-shaped steel sheet pile with an ultra-large arm that exceeds 900mm in width has recently been developed, and its rigidity (second moment of bending in the bending direction) is also extremely large, which is extremely useful for correcting the bending of the entire product. However, there are cases where correction is impossible due to the ability of the press straightener. The correction method described in Patent Document 1 is intended for steel sheet piles having a width dimension of up to about 650 mm as in the examples.

  Moreover, in the steel sheet pile having the arm portion, the bending of the arm portion and the joint portion often differs between the left and right flanges. However, in the correction method disclosed in Patent Document 1, the pressing applied to the left and right pressing dies 70 is performed. The force a was equal and did not correspond to such a case.

  This invention is made | formed in view of such a problem, and it aims at provision of the press correction method applicable to the bending correction of the U-shaped steel sheet pile which has an arm part.

  The present inventors conducted a bending correction experiment for a hat-type steel sheet pile having an effective width of 900 mm by changing the method of applying a pressing force to the flange and the location where the pressing force is applied to the flange in various ways.

  As a result, as a press correction method: 1. Method of holding (restraining) the outer surface of one flange and pressing the outer surface of the other flange (conventional method 1); When the flange outer surface of one flange is held (restrained) and the flange outer surface of the other flange is pressed while the flange outer surface of the other flange is pressed (conventional method 2) Could not correct the bend due to the limited capacity of the press straightener used in the experiment.

  On the other hand, if only one of the flanges is held (restrained) and applied with a pressing force, it is possible to correct the bending of the steel sheet pile, and further hold (restrain) the portion from the flange to the joint, It has been found that when a pressing force is applied to the location, the joint can be accurately corrected with a smaller pressing force.

The present invention was made by further study based on the obtained knowledge, that is, the present invention is
1. In a method of placing a U-shaped steel sheet pile having an arm part between a web part, a flange part, a joint part, and a joint part and the flange part on a table roller, and correcting the bending in the left-right direction,
A press straightening method for a U-shaped steel sheet pile having an arm, wherein only one flange is constrained by a holding mold and a pressing force is applied by a pressing mold.

  2. 2. The press correction method for a U-shaped steel sheet pile having an arm portion according to claim 1, wherein the portion that is restrained by the holding die and is applied with the pressing die by the pressing die is a portion from the flange to the arm portion.

  3. The pressing correction method for the U-shaped steel sheet pile having the arm portion according to 2, wherein the pressing force is applied from a horizontal direction and a vertical direction.

  4). The U-shaped steel sheet pile having an arm portion according to any one of claims 1 to 3, wherein when placing the U-shaped steel sheet pile on the table roller, the web surface is inclined from the horizontal on the table roller. Press straightening method.

  According to the present invention, only the flange on one side of the steel sheet pile is applied with the pressing force from the inner surface or the outer surface in the horizontal direction or in the horizontal direction and the vertical direction, and the bending in the left and right direction on the flange side is corrected. It is possible to reduce the correction load as compared with the case where the pressing pressure is applied to.

  When the vertical pressing is applied at the same time, the bending deformation of the arm is also applied, so that the bending correction effect can be enhanced.

  In addition, when the steel sheet pile is installed in a state where the web surface is inclined from the horizontal from the table roller and the correction is performed, a pressing force is applied in the horizontal direction, so that the bending correction of the arm is also performed in addition to the bending correction of the flange. This can be easily performed, and the bending correction effect can be enhanced while preventing an increase in the correction load.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  1A and 1B are diagrams for explaining an embodiment of a press correction method according to the present invention, wherein FIG. 1A is a cross-sectional direction of a steel sheet pile, and FIG. In the figure, 1 is a U-shaped steel sheet pile (hereinafter referred to as a steel sheet pile) having an arm portion between a joint portion and a flange portion, 2 is a web portion, 3 is a flange portion, 3a is an inner surface side of the flange portion 3, and 3b is a flange portion. 3 is an outer surface side, 4 is a joint portion, 5 is an arm portion, 6 is a holding die, 7 is a pressing die, 8 is a table roller, and a is a pressing force.

  The steel sheet pile 1 is placed on the table roller 8 in a U shape so that the table roller 8 and the web portion 2 are in contact with each other. In press correction, the holding mold 6 is disposed on the outer surface side 3b of the flange portion 3 and the pressing mold 7 is disposed on the inner surface side 3a of the flange portion 3 so that the pressing pressure a is applied only to one flange 3. .

  The pressing mold 7 is disposed on the inner surface side 3a of the flange portion 3 at a position intermediate between the two holding molds 6 so as to support the flange 3 at three points, and applies a pressing pressure a horizontally. . The side pressed against the flange portion 3 by the holding die 6 and the pressing die 7 is formed so that the portion from the flange of the steel sheet pile 1 to the arm portion abuts.

  Since the holding die 6 and the pressing die 7 are pressed against the flange portion 3 in this way, the bending moment force concentrates on the corresponding portion when the pressing force a is applied, and the bending of the joint portion is efficient. Corrected.

  In addition, in this invention, the part from a flange to an arm part is a part which changes continuously from a flange to an arm part, and shall include a part or full length of a flange part, and a part or full length of an arm part. In the press correction method, correction is performed while the steel sheet pile 1 is conveyed by the table roller 8, so that the bending of the joint portion can be corrected over the entire length of the steel sheet pile.

  In the above description, the holding mold 6 is disposed on the outer surface side 3b of the flange 3 and the pressing mold 7 is disposed on the inner surface side 3a of the flange 3. However, the pressing mold 7 is disposed on the outer surface side 3b of the flange 3. 6 may be arranged on the inner surface side 3a of the flange 3 (FIG. 2).

  Further, in FIG. 1, when press correction is performed, the holding mold 6 is fixed in position with respect to the steel sheet pile 1, and the pressing mold 7 moves only in the horizontal direction, but the holding mold 6 and the pressing mold 7. When both are movable in the vertical direction and a vertical force b is applied, the arm portion is bent in the vertical direction, and the bending of the joint portion can be corrected more efficiently (FIG. 3).

  Further, when pressing the outer surface of the flange, it is difficult to apply a vertical force with the pressing mold. Therefore, the pressing mold 7 is fixed to the steel sheet pile 1 in the vertical direction, and the arm portion and the arm portion. It is preferable to provide a pressing die 9 for applying a vertical force b to the nearby flange portion (FIG. 6).

  FIG. 4 shows another embodiment of the press straightening method according to the present invention, in which the holding mold 6 is provided with a portion to be inserted between the steel sheet pile 1 and the table roller 8, and the steel sheet pile 1 is attached to the table roller 8. Place it at an angle of θ and perform press correction.

  Without applying a force in the vertical direction, the pressing of the flange and the pressing of the arm can be performed at the same time, and the correction effect of the bending of the joint can be enhanced.

  According to the method shown in the upper figure, compared to the case where the steel sheet pile 1 is placed horizontally on the table roller 8, the surface 6a of the holding mold 6 and the pressing force a are more orthogonal, so the holding mold 6 In the state where the steel sheet pile 1 is lifted, the pressing force is prevented from being applied (FIG. 5), and the problem that the cross-sectional shape is impaired is reduced. In particular, it is effective for a steel sheet pile having a shape in which the U-shaped opening is widened toward the end.

  FIG. 7 shows another embodiment of the press straightening method according to the present invention. In order to obtain the same effect as in FIG. 4, the steel sheet pile 1 is tilted at an angle θ with respect to the table roller 8 to perform press straightening. The case where the lower part of the type | mold 7 is extended and the part inserted between the steel sheet pile 1 and the table roller 8 is provided is shown.

  When correcting a steel sheet pile using the press straightening method according to the present invention, the conveyance direction of the steel sheet pile conveyed on the table roller 8 is selected according to the bending form of the steel sheet pile.

  For example, if both the left and right joints of the steel sheet pile are bent to the left, press the inner surface of the left flange to correct the bending of the left joint, and then press the outer surface of the right flange to Correct the bend.

  For the case where the left joint is bent to the left and the right joint is bent to the right, the inner surface of the left flange is pressed to correct the bending of the left joint, and then the steel sheet pile is inverted, Press the inner surface to correct the bending of the right joint. As described above, according to the present invention, it is possible to correct the bending even when the bending directions of the left and right joint portions are locally different.

  Both the left joint part and the right joint part of the steel sheet pile (overall length 10 m) were bent in the left direction, and those having a bending amount of about 30 mm at 10 m were corrected by press correction. The steel sheet pile has the hat shape shown in FIG. 12, the web thickness tw = 10.8 mm, the flange thickness tf = 8 mm, the arm thickness tb = 10 mm, the flange surface inclination α = 48 °, the total width W = 933 mm, the total height. The cross-sectional shape was h = 241 mm.

  As the press straightening method 1, according to the example of the present invention shown in FIG. 1, the inner surface of the left flange is first pressed to correct the bending of the left joint, and then the outer surface of the right flange is pressed to correct the bending of the right joint. (Applicable example 1).

  As the press straightening method 2, as shown in FIG. 10 (b), a method of holding one flange outer surface and pressing the other flange outer surface (Comparative Example 1), and as the press straightening method 3, one flange shown in FIG. Correction was performed using a method (Comparative Example 2) of holding the outer surface and pressing the inner surface of the held flange and the outer surface of the other flange.

  The press straightening machine is common to all press straightening methods, and has specifications of a horizontal pressing force of up to 1000 kN and a horizontal pressing force of up to 2000 kN. The distance between the pressing mold and the holding mold was 1 m (the distance between both holding molds was 2 m).

  Table 1 shows the results. In the first conforming example, the bending amount δ can be corrected to 8 mm or less with a length of 10 m for both the left and right joints. Since the bending could not be corrected, the correction was aborted. Also in Comparative Example 2, the steel sheet pile was only elastically deformed within the equipment capacity range of this press, and the bending could not be corrected sufficiently.

  Next, a steel sheet pile with the same cross-sectional shape and length, and a steel sheet pile with a large amount of bending in the left and right joints with a bending amount at 10 m of about 50 mm were corrected.

  As the press straightening method 1, according to the example of the present invention shown in FIG. 1, the inner surface of the left flange is first pressed to correct the bending of the left joint, and then the outer surface of the right flange is pressed to correct the bending of the right joint. (Conformity example 2).

  The press correction method 2 shown in FIG. 3 (or FIG. 6) is a method according to an example of the present invention for applying a vertical force (conformation example 3), and the press correction method 3 is shown in FIG. 4 (or FIG. 7). Then, three methods of the method according to the present invention in which the web is inclined with respect to the table roller 8 (conformance example 4) were performed.

  The correction of the left and right joints was performed in the same order as in Example 1 above. In Conformance Example 3, the reduction from the upper part of the arm was applied so that the pressing force was 10% of the pressing force in the horizontal direction. Moreover, in the adaptation example 4, the collar was provided in the lower part of the metal mold | die on the receiving side, and the web surface was made to incline 10 degrees from a horizontal surface.

  In each case, while feeding the material in the longitudinal direction, press several times at the longitudinal position to check the amount of bending, and if the bending is not sufficiently corrected, press again and allow the amount of bending. Value (10 mm / 10 m).

  Table 2 shows the results. In any of the press straightening methods, the amount of bending was allowed to be an acceptable value. In particular, in conformity examples 3 and 4, the left and right joints can be straightened with two presses at each location in the longitudinal direction. Correction was possible.

  On the other hand, when the inner surface of the flange was pressed in the conforming example 2, the material was also lifted on the flange holding side, so that the amount of correction per stroke could not be taken sufficiently, and bending was performed with three presses at each longitudinal point. It took a little time for correction, compared with the corresponding examples 3 and 4.

Example of the present invention. Example of the present invention. Example of the present invention. Example of the present invention. The figure explaining the state which a steel sheet pile floats in a receiving die position at the time of press correction. Example of the present invention. Example of the present invention. The figure explaining upper curvature. The figure explaining bending. Conventional example. Conventional example. The figure explaining the cross-sectional shape of the U-shaped steel sheet pile which has an arm part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,100: Steel sheet pile 2 which has an arm part, 200: Web 3, 300: Flange 4: Joint part 5: Arm part 6, 60: Holding die 7, 70: Pressing die 8, 80: Table roller 9: Pressing dies 3a, 300a: flange inner surface side 3b, 300b: flange outer surface side

Claims (4)

In a method of placing a U-shaped steel sheet pile having an arm part between a web part, a flange part, a joint part, and a joint part and the flange part on a table roller, and correcting the bending in the left-right direction,
A press straightening method for a U-shaped steel sheet pile having an arm, wherein only one flange is constrained by a holding mold and a pressing force is applied by a pressing mold.   2. The method for correcting the press of a U-shaped steel sheet pile having an arm portion according to claim 1, wherein the portion that is restrained by the holding die and that gives the pressing force by the pressing die is a portion from the flange to the arm portion.   3. A method for correcting a press of a U-shaped steel sheet pile having an arm according to claim 2, wherein the pressing force is applied from a horizontal direction and a vertical direction.   The U-shaped steel sheet pile is placed on the table roller, and the web surface is inclined from the horizontal on the table roller. The U having the arm portion according to any one of claims 1 to 3, Press straightening method for type steel sheet pile.

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