JP4502923B2 - H-section steel drawing method - Google Patents

Description

  The present invention relates to a method for drawing an H-shaped steel embedded in an underground wall or the like.

 In this invention, H-shaped steel is buried in the ground as a core pile or as a pillar in the underground continuous wall or mountain retaining wall, etc., and the excavation of the ground is completed, and the retaining wall is accompanied with the restoration after the construction of the structure. In some cases, the upper part of the H-shaped steel is pulled out when the parts are removed. In this case, there is a patent document exemplified below as a countermeasure.

By the way, as a problem in this case, the upper and lower H-shaped steels are joined with bolts and nuts, and all the bolts use long bolts. A number of bolts and nuts are required.
Japanese Patent No. 3404315 Usually, a H-shaped steel is manufactured using a roll. As a result, in the JIS standard, there are tolerances in web height, flange width, thickness, squareness, etc.

  In the present invention, a box-shaped joint metal fitting is arranged across the joints of the upper and lower H-section steels, and the joint plate on the ground mountain side of the box-shaped joint metal fitting and the flange of the lower H-section steel on the ground mountain side are joined by bolts and nuts. In the first half of the box-shaped joint, the excavation side joining plate, the excavating side joining plate, the excavating side top and bottom H-shaped steel, and the accessory plate with the nut detent plate are interposed and joined with bolts and nuts. Yes, the H-section steel is characterized in that the excavation is completed at the time of removal work, the bolts of the upper H-section steel on the excavation side are removed and the upper H-section steel is pulled out with the refilling after the construction of the structure The box-shaped joint fitting is manufactured in advance by making a U-shaped body, bolting the H-shaped steel excavation side flange, the joining plate and the accessory plate, and then inserting the ground plate from the top of the U-shaped body. The lower H-section is bolted and the web plate and ground The side plate fillet weld.

  In the present invention, the strength of the joints of the upper and lower H-shaped steels is large, the bending strength is large, and the number of bolts to be used is small. In the present invention, a U-shaped box-shaped joint metal body is manufactured, and a ground-side joining plate 5 is assembled and welded to completely absorb the dimensional tolerance of the H-section steel, and the upper and lower H-section steel 1 and the box By eliminating the gap between the flange portion and the joining plate portion of the joint member 2, it is possible to secure a state in which the amount of deformation of the ground tip in a self-supporting state is close to that of an H-shaped steel without a joint.

  Furthermore, in terms of strength, it is possible to maintain the same strength as the one for the excavation side bending moment, and to ensure sufficient strength for the design against the bending moment when standing on the natural ground side. Can have.

  The present invention is carried out when the H-section steel buried in the underground such as a continuous wall that is a mountain retaining wall is pulled out and removed along with excavation of the ground. Prior to embedment in the ground, the box-shaped joint metal fitting 2 is arranged across the joint portions of the upper and lower H-section steels 1, 1 and the joint plate 3 on the ground mountain side A of the box-like joint metal fitting 2 The flange of the lower H-section steel 1 on the natural ground side is joined by a bolt and nut 4, and the joint plate 5 on the excavation side B of the box-shaped fitting and the upper and lower H-section steels 1 and 1 on the excavation side are non-rotating nuts. It is joined by bolts and nuts 8 with an accessory plate 7 with an attached plate 6 interposed, and excavation is completed at the time of removal work, and the upper H-section steel on the excavation side is accompanied by refilling after construction of the structure. Remove the bolts and nuts 8 and pull out the upper H-section steel.

  Usually, a H-shaped steel is manufactured using a roll. As a result, in the JIS standard, there are tolerances in web height, flange width, thickness and squareness of each. Taking the example of the flange width 200mm series (H-400 × 200 × 8 × 13) that is most frequently used for soil continuous underground walls, the web height is 400mm ± 3.0mm and the flange is concretely shown as JIS standard. The width is 200 mm ± 3.0 mm.

The actual product web height H is in a dimension having a range of 403 mm to 397 mm.
The box-shaped fitting 2 of the present invention is manufactured separately, and the box-shaped fitting 2 having a maximum web height H of 403 mm + 2.0 mm, that is, a height of 405 mm, is produced in order to join the H-shaped steel 1 in combination. Then, the upper and lower H-section steels 1 are inserted from the left and right to perform the combined joining. Since it is manufactured separately, dimensions that can accommodate the maximum height of the web are also required.

  If the box-shaped metal fitting 2 having a web height of 405 mm and a web height of 397 mm, which is the minimum dimension of the H-shaped steel, are combined and joined, the outside 1 of the H-shaped steel flange and the joining plate 3 on the natural ground side A There is a gap of 8.0 mm between them. This interval is filled with a camber and combined joining is performed, followed by tightening with a bolt.

  When combined joining is performed without filling the camber, the bolt 8 on the excavation side is pulled out, the first-stage beam is disassembled, and when the retaining wall is in a self-supporting state, the joint plate on the ground side A of the box joint 2 Since there is a large gap between 3 and the outside of the flange of H-section steel 1, the upper H-section of H-section steel 1 bites to excavation side B, so that the top of the H-section steel is several times that Will also move and deform in proportion. The magnitude of the deformation of the retaining wall causes the subsidence of the local board, causing a major obstacle.

  It is not impossible to make a box-shaped joint by measuring the height of the H-shaped steel web in advance. It must be manufactured in advance with dimensions that take into consideration the perpendicularity to the height, and since the upper and lower H-section steel is inserted and joined to the box-shaped joint fitting 2 from the left and right, the minimum measured value is about 1.0 mm to 2.0 mm If it is not made large, it will be in the situation where combination joining cannot be performed. There will be a gap between the plate 3 of the box-shaped joint hardware 2 and the flange outer surface of the H-section steel 1. It is practically impossible to insert the camber entirely at intervals of 1.0 mm to 2.0 mm. The interval will be applied as it is. This slight gap deformation results in a value that is 15 to 20 times the amount of deformation at the top of the self-supporting state.

  As explained in the previous section, in order not to generate a gap between the outer flange surface of the H-section steel 1 on the natural ground side and the plate 3 of the box-shaped joint metal fitting 2, first, the U-shape of the box-shaped joint metal fitting is previously set. To manufacture. At this time, the web plate 9 of the joining metal and the outer corner portion 10 and the inner corner portion 11 of the joining plate 5 on the excavation side are subjected to predetermined fillet welding on both sides.

Next, the formed U-shape, the upper and lower H-section steel 1 and the plate 6 with a nut rotation stopper are joined together using bolts and nuts 8.
The completed box-shaped fitting 2 can be welded with the integrated dimensions of an H-shaped steel that completely absorbs the tolerances of the H-shaped steel 1. There is no gap between the joining plates. By adopting this method, on-site welding requires only full length welding of the natural mountain side outer corner 12, and the work is equivalent to a normal fillet work and there is no problem. Fillet welding of the inner corner 13 on the natural mountain side, which is difficult for welding work, is welding only about 50mm from the end, and it is possible to perform downward welding by simply rotating the H-section steel 1 180 degrees. there is no problem.

  The corners of the joint plate 5 and the web plate 9 on the excavation side of the box-shaped joint fitting 2 are in a single U-shaped state, the inside is subjected to full-length fillet welding on the outside, and the opposite ground-side joining plate 3 is formed on the outside fillet Only 12 full length fillets were welded. The fillet weld length is in a state where only half of the ground is welded compared to the excavation side.

  In the design of the retaining wall, the bending moment generated in the H-shaped steel is the bending moment that occurs during the self-supporting situation after dismantling of the cut beam after performing self-supporting and refilling during the primary excavation. The moment is about 20% at the maximum. This means that there is no design problem if the fillet weld on the ground side is about 20% of the fillet weld required for the bending moment on the excavation side. In this application, half fillet welding is easy. It is a shape that can be carried out and can secure sufficient strength in design.

  If not U-shaped, the upper and lower flange joint plates 3 and 5 are bolted, and then the fillet weld is performed on the web plate 9, and the inner corners 11 and 13 are the H-section steel 1 web. And the web plate 9 are very narrow (about 100 mm for the flange 200 series), welding to the center of the H-shaped steel joint is not possible, and fillet welding is possible only about 50 mm from the end. As a result, because the weld length is insufficient, the bending moment on the excavation side is insufficient in strength and cannot be used for design, and cannot be used for construction work.

  By manufacturing the U-shape of this application and assembling and welding the natural ground side joining plate 5, the dimensional tolerance of the H-section steel is completely absorbed, and the flange portion of the upper and lower H-section steel 1 and the box-shaped joint fitting 2 By eliminating the gap between the joining plate portions, it is possible to secure a state in which the amount of deformation at the top of the ground in the self-standing state is close to that of an H-section steel without a joint.

  Furthermore, in terms of strength, it is possible to maintain the same strength as the one for the excavation side bending moment, and to ensure sufficient strength for the design against the bending moment when standing on the natural ground side. Can have.

  The effects of the present invention are summarized as follows.

(1) The excavation side is stronger than the base metal. In other words, the bolt on the excavation side flange is fixed with two plates, a box plate and a nut locking plate, so that the base metal bending strength Z = 1,143 cm ³ , box bending strength Z1 = 1,582 cm ³ , F = 1.38 times It has the strength of

(2) The number of bolts can be halved by using a high-strength hexagon bolt with two-surface shear. That is, since the excavation side flange is tightened with the flange plate of the box and the plate with a nut detent, the bolt can be used by two-surface shearing, so the number of bolts can be half that of the patent literature.

(3) The use of a plate with a nut detent eliminates the need for spot welding of bolts, that is, with a flange width of 200 mm series (H-400 x 200 x 8 x 13) that is most commonly used for soil continuous underground walls. After fixing the box with bolts, spot welding for preventing the rotation of the nut is practically impossible when the box is used because the flange width is small.

(4) Although the length of the box in the vertical direction is short, the excavation side flange is fixed by two-surface shearing, so the entire pile is straight and the excavation side flange width is completely fixed. Pile can be inserted vertically into the soil.

(5) After making U-shape in advance and bolting the H-shaped steel excavation side flange joint plate and accessory plate, insert the ground plate into the upper part of the U-shape, and lower H-shape steel and bolt By joining the web plate and the ground plate, the top and bottom H-shaped steel and the box-shaped fitting are completely spaced apart from each other regardless of the crossing of the H-shaped steel. The deformation amount at the time of self-supporting of the wall can be ensured to be almost equal to that of a single H-shaped steel without a joint.

It is an elevation view of the implementation status. It is a front view of the junction part on the excavation side. It is a front view of the joint part on the natural mountain side. It is sectional drawing of a downward pile. It is a side view of a junction part. It is a front view of an accessory plate. It is a three-dimensional view of a U-shaped joining metal fitting. It is sectional drawing of an upper pile.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... H-shaped steel 2 ... Box-shaped joining metal fitting 3 ... Ground plate side joining plate 4 ... Bolt and nut 5 ... Excavation side joining plate 6 ... Nut detent plate 7 ... Saddle plate 8 ... Bolt / nut 9 ... Web plate DESCRIPTION OF SYMBOLS 10 ... Excavation side outer corner 11 ... Excavation side inner corner 12 ... Natural mountain side outer corner 13 ... Natural mountain side inner corner A ... Natural mountain side B ... Excavation side

Claims (2)

  Box-shaped joint metal fittings are disposed across the joints of the upper and lower H-section steels, and the joint plate on the ground mountain side of the box-shaped joint metal fittings and the flange of the lower H-section steel on the ground mountain side are joined with bolts and nuts, It is joined by bolts and nuts with a joint plate on the excavation side of the box-shaped joint fitting, an upper and lower H-section steel on the excavation side, and a plate with a nut detent plate interposed, and excavation is completed at the time of removal work A method of pulling out the H-section steel, wherein the bolts of the upper H-section steel on the excavation side are removed and the upper H-section steel is pulled out with the backfill after the construction of the structure. Box-shaped metal fittings are manufactured in advance for the U-shaped body, and the H-shaped steel excavation side flange, bonding plate and accessory plate are bolted together. The method of drawing an H-section steel according to claim 1, wherein joining is performed, and the web plate and the ground plate are further fillet welded.

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