JP3874253B2 - Steel element joint opening closing member, and steel element joint opening protecting method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an opening closing member that closes an opening of a steel element joint, and a method for protecting the opening of a steel element joint using the opening closing member.
[0002]
[Prior art]
Conventionally, when excavating the ground downward from the ground, a continuous wall-shaped reinforced concrete structure is constructed underground to surround the space to be excavated, and this structure (hereinafter referred to as “underground continuous wall”) May be used as earth retaining work during excavation, and as part of the main structure.
[0003]
In the continuous underground wall, first, a rectangular reinforced concrete wall structure element extending substantially vertically downward from near the ground to the basement is constructed, and similar wall structure elements are sequentially connected in the horizontal direction, and finally the wall. A building structure is built underground. For each wall structural element, first, two frame members made of steel or the like are inserted substantially vertically downward so that they are parallel to each other.
[0004]
After that, the inside of the frame is dug down. At that time, the excavation hole is filled with muddy water (stabilizing liquid) such as bentonite, and excavation is performed while preventing the collapse of the inner wall of the hole. After the excavation is completed, a rebar basket is inserted into the excavated hole with a crane or the like. After that, the reinforced concrete wall is constructed by placing the stabilizing liquid with concrete by using an underwater concrete method. The underground continuous wall may be referred to as “continuous underground wall” or “underground continuous wall”.
[0005]
However, the conventional underground continuous wall construction method has the following problems.
[0006]
(1) When the underground continuous wall itself is used as a earth retaining work, it is complicated because the earth retaining work is required when constructing the underground continuous wall.
[0007]
{Circle around (2)} When using muddy water as the earth retaining work in the hole of the wall structural element, a muddy water generating plant, piping, etc. are required, which requires labor and cost for installation work.
[0008]
Recently, in order to solve these problems, a method of constructing an underground continuous wall using a steel element (hereinafter referred to as “steel element type underground continuous wall construction method”) has been proposed.
[0009]
FIG. 9: is sectional drawing which shows the structure of the reference | standard pipe steel element used for the steel element type underground continuous wall construction method. As shown in FIG. 9, the reference pipe steel element 10 has two steel plate members 11, two steel plate members 12, and four joints 13. The steel plate member 11 and the other steel plate member 11 extend in the element axial direction so as to face each other, and the steel plate member 12 and the other steel plate members 12 face each other. It extends in the element axial direction so as to be perpendicular to the steel plate-like member 11. Thereby, a rectangular tubular ("B" -shaped) cross section is formed as a whole.
[0010]
Further, joints 13 are arranged along the element axial direction at each of the four corners of the rectangular tubular cross section formed by the steel plate-like members 11, 12, 11, 12. The joint 13 in the reference pipe steel element 10 corresponds to a reference pipe joint.
[0011]
The cross section of each joint 13 has a substantially “C” -shaped fitting portion 13a and a base portion 13b connected to the back of the fitting portion 13a. Moreover, the fitting part 13a has the two protrusion parts 13c and 13d. The tip of the protrusion 13c is expanded in a bulb shape. Further, an intermediate portion between the protruding portion 13c and the protruding portion 13d is a fitting groove 13e extending in the element axial direction with a substantially elliptical cross section. 9 (B) shows a cross section of the joint at the upper left and lower right corners in FIG. 9 (A), but the shape of the joint at the upper right and lower left corners in FIG. 9 (A) is the same. The joint 13 is used at a symmetrical position, and its configuration is exactly the same as in FIG.
[0012]
Moreover, each connection location of each steel plate-shaped member 11, 12 and each joint 13 is joined by a welded portion W. This connection may be a mechanical connection such as a bolt.
[0013]
When a force in the direction perpendicular to the element axis is applied to the vicinity of the tip of the protruding portion 13c of the joint 13 with the above-described configuration, for example, when pulling in the left direction in FIG. 9) is transmitted from the projecting portion 13c to the base portion 13b, from the base portion 13b to the steel plate member 11, and at the left end of the steel plate member 11 in FIG. A tensile force in the left direction in (B) is applied.
[0014]
On the other hand, when a force in the direction perpendicular to the element axis is applied to the vicinity of the tip of the protruding portion 13d of the joint 13, for example, when pulling in the left direction in FIG. 9B, this tensile force (hereinafter referred to as “second tensile force”). Is transmitted from the protruding portion 13d to the steel plate-like member 11 via the base portion 13b, and a tensile force in the left direction in FIG. 9B is applied to the left end of the steel plate-like member 11 in FIG. 9B. Will act.
[0015]
From the above, the protruding portions 13c and 13d of the joint 13 and the base portion 13b have a predetermined resistance that can resist the force in the direction perpendicular to the element axis (for example, the first tensile force and the second tensile force) applied from the outside. It has strength and a predetermined cross section. Further, considering that the combined force of a part of the first tensile force and a part of the second tensile force acts on the protruding portion 13d of the joint 13, a predetermined strength that can resist the force is obtained. It has a predetermined cross section. For example, the thickness t1 of the protruding portion 13d is sufficient. Further, in consideration of the combined force of the first tensile force and a part of the second tensile force acting on the base portion 13b of the joint 13, a predetermined strength and a predetermined cross section that can resist the force ( For example, it has a sufficient thickness). Further, the steel plate-like member 11 has a predetermined strength and a predetermined cross section capable of resisting the force in the direction perpendicular to the element axis transmitted from the joint 13.
[0016]
Further, in the reference pipe steel element 10, the cross-sectional shape of each joint 13 is the cross-section of the steel plate-like members 11, 12, 11, 12, as shown in FIGS. 9A and 9B. It is substantially contained in the inside of the four corners of the rectangle constituted by the outer edge lines and the extended lines of the outer edge lines. As shown in FIG. 9B, only a part of the protrusion 13c protrudes outside the corner.
[0017]
Therefore, when inserting the soil or the like inside the reference pipe steel element 10 into the ground while excavating by mechanical excavation using an auger drill or the like equipped in the element or by manual excavation by an operator, There are the following advantages.
[0018]
First, the insertion is easy because the insertion resistance to the ground is small. Moreover, since the joint 13 does not protrude, it is protected from unexpected damage. Furthermore, it is possible to considerably prevent earth and sand from entering the fitting groove 13e.
[0019]
FIG. 10: is sectional drawing which shows the structure of the general part steel element used for the steel element type underground continuous wall construction method. FIG. 11 is a perspective view showing the configuration of the general steel element shown in FIG.
[0020]
As shown in FIGS. 10 and 11, the general steel element 20 has two steel plate members 21, one steel plate member 22, two joints 13, and two joints 23. is doing. The steel plate-like member 21 and the other steel plate-like member 21 are extended in the element axial direction so as to face each other, and the steel plate-like member 22 is arranged at a right angle to the steel plate-like member 21. It extends in the axial direction. Thus, a “U” -shaped cross section is formed as a whole.
[0021]
Of the four corners of the “U” -shaped cross section formed by the steel plate-like members 21, 22, 21, the corner opened to the outside (the upper right corner in FIG. 10A) And a lower right corner (hereinafter referred to as “open side corner”), a joint 23 is disposed along the element axial direction. The joint 23 in the general steel element 20 corresponds to a general first joint.
[0022]
Of the four corners of the “U” -shaped cross section formed by the steel plate-like members 21, 22, 21, the corner closed to the outside (the upper left corner in FIG. 10A) And the lower left corner (hereinafter referred to as “closed side corner”) are provided with the joint 13 described above along the element axial direction. The joint 13 in the general steel element 20 corresponds to a general second joint. Further, the joints 13 and 23 in the general steel element 20 correspond to general joints.
[0023]
The cross section of each joint 23 has a substantially “C” -shaped fitting portion 23a and a base portion 23b connected to the back of the fitting portion 23a. Moreover, the fitting part 23a has the two protrusion parts 23c and 23d. The tip of the protrusion 23c is enlarged in a bulb shape. Further, an intermediate portion between the protruding portion 23c and the protruding portion 23d is a fitting groove 23e extending in the element axial direction with a substantially elliptical cross section. 10B shows a cross-section of the joint at the upper right corner in FIG. 10A, the joint 23 having the same shape is also formed in the joint at the lower right corner in FIG. 10A. It is used in a symmetric position, and its configuration is exactly the same as in FIG. Moreover, the structure of the joint 13 and its vicinity is completely the same as the joint 13 in the reference | standard pipe steel element 10 mentioned above.
[0024]
In addition, each connection point between each steel plate-like member 21, 22 and each joint 13, 23 is joined by a welded portion W. This connection may be a mechanical connection such as a bolt.
[0025]
When a force in the direction perpendicular to the element axis is applied to the vicinity of the tip of the protruding portion 23c of the joint 23 with the above-described configuration, for example, when pulling in the right direction in FIG. "Third tensile force" is transmitted from the projecting portion 23c to the base portion 23b, from the base portion 23b to the steel plate member 21, and at the right end of the steel plate member 21 in FIG. A tensile force in the right direction in (B) is applied.
[0026]
On the other hand, when a force in the direction perpendicular to the element axis is applied to the vicinity of the tip of the protruding portion 23d of the joint 23, for example, when pulling rightward in FIG. 10B, this tensile force (hereinafter referred to as “fourth tensile force”). Is transmitted from the projecting portion 23d to the base portion 23b, from the base portion 23b to the steel plate-like member 21, and to the right end in FIG. 10B of the steel plate-like member 21 at the right side in FIG. 10B. Apply a tensile force in the direction. Further, due to the fourth tensile force, a bending moment in the counterclockwise direction in FIG. 10B is applied to the protruding portion 23d.
[0027]
From the above, the protrusions 23c and 23d of the joint 23 have a predetermined strength and a predetermined resistance that can resist the force (for example, the third tensile force and the fourth tensile force) perpendicular to the element axis applied from the outside. It has a cross section. Further, considering that the combined force of the fourth tensile force and the bending moment resulting from the fourth tensile force acts on the protruding portion 23d of the joint 23, a predetermined strength that can resist the force is applied. And has a predetermined cross section. For example, the thickness t2 of the protrusion 23d is sufficient. Further, in consideration of the combined force of the third tensile force and the fourth tensile force acting on the base portion 23b of the joint 23, a predetermined strength and a predetermined cross section (for example, sufficient strength) that can resist the force are applied. Thickness). The steel plate-like members 21 and 22 have a predetermined strength and a predetermined cross section that can resist the force in the direction perpendicular to the element axis transmitted from the joints 13 and 23.
[0028]
Moreover, in the general part steel element 20, as shown in FIG. 10 (A), the cross-sectional shape of each joint 13 is the outer edge line of the cross section of the steel plate-like members 21, 22, 21 and the outer edge line. It is substantially contained within the four corners of the rectangle formed by the extension lines. Only a part of the protruding portion 13c protrudes outside the corner.
[0029]
Next, the insertion of the above-described general steel element 20 into the ground substantially vertically downward and the construction of the underground continuous wall will be described with reference to FIG. FIG. 12 is a cross-sectional view showing a joined state of the reference pipe steel element 10 and the general part steel element 20 described above. 12A is a cross-sectional view showing the overall state of the joined state of the reference pipe steel element 10 and the general steel element 20, and FIG. 12B is a cross-sectional view of FIG. It is an expanded sectional view of the joint part vicinity of the joint 13 and the joint 23 in FIG. FIGS. 12A and 12B are cross-sectional views as viewed from the element axial direction (cross-sectional views taken along a plane perpendicular to the element axial direction).
[0030]
First, as described above, the reference pipe steel element 10 is inserted substantially vertically downward in the ground (hereinafter referred to as “first step”). Then, each of the joints 23 and 23 provided in the open side corner of the general steel element 20 is replaced with two of the joints 13 of the reference pipe steel element 10 (for example, the upper left corner in FIG. 12A). And the joints at the lower left corner). Then, in the state in which both the joints are fitted, while the general steel element 20 is aligned with the reference pipe steel element 10, the element axial direction (substantially vertically downward) is the same as in the case of the reference pipe steel element 10. In the ground) (hereinafter referred to as “second step”). Thereby, it will be in the state shown to FIG. 12 (A) and FIG. 12 (B).
[0031]
In this case, in the joint 13 of the reference pipe steel element 10 in the joined state and the joint 23 of the general steel element 20, the protrusion 23c of the joint 23 is enlarged in the fitting groove 13e of the joint 13. The tip of the protrusion 13c of the joint 13 is inserted into and fitted into the fitting groove 23e of the joint 23.
[0032]
Next, after the second step, each of the joints 23, 23 provided at the open side corners of the new general steel element 20 is closed on the closed side of the general steel element 20 already inserted into the ground. The joints 13 and 13 provided at the corners are fitted and joined. And in the state which fitted both the joints, while making the new general part steel element 20 along the already inserted general part steel element 20 into the element axial direction, it is the substantially vertical downward direction in the ground. (Hereinafter referred to as “third step”). Hereinafter, by repeating this third step in sequence, the element structure can be constituted by the steel elements 10 and 20 etc. inserted into the ground and joined to each other.
[0033]
Next, an element filler is filled into a columnar space formed inside each steel element of the element structure (hereinafter referred to as “fourth step”). Concrete, mortar, or the like is used as the element filler. Thereby, an underground continuous wall can be constructed in the ground.
[0034]
Thereafter, the underground continuous wall formed in the ground can be used as a soil retaining work, and the ground inside the element structure can be excavated, and the inner surface of the element can be covered with concrete as necessary.
[0035]
In the steel element type underground continuous wall construction method described above, when each steel element is inserted into the ground, a dummy joint 200 as shown in FIG. Was wearing.
[0036]
A dummy joint 200 shown in FIG. 13 is of a type that is attached to the joint 13 of a steel element, and is made of rubber or the like, and has a generally “U” -shaped fitting portion 200a and behind the fitting portion 200a. It has a base 200b to be connected. Moreover, the fitting part 200a has the two protrusion parts 200c and 200d. The tip of the protrusion 200 is enlarged. Further, an intermediate portion between the protruding portion 200c and the protruding portion 200d is a fitting groove 200e having a substantially rectangular cross section and extending in the element axial direction.
[0037]
By mounting such a dummy joint 200, the opening of the fitting groove 13e is closed, so that earth or sand or dust may enter the internal space of the fitting groove 13e of the joint 13 of the steel element. The advantage is that it is prevented and subsequent insertion of other steel elements is facilitated.
[0038]
[Problems to be solved by the invention]
However, the conventional dummy joint described above has the following problems.
[0039]
(I) Since the steel element is inserted vertically downward, when trying to insert the next steel element adjacent to a certain steel element, the dummy joint is directed downward into the ground. It is necessary to drop it from the joint to the outside. For this reason, a large force is required for pushing the steel element.
[0040]
(Ii) In addition, when the ground is hard, it is difficult to push the dummy joint into the ground, and resistance to the insertion of the steel element may deteriorate the workability of the steel element insertion method itself. It was.
[0041]
(Iii) Moreover, the dummy joint removed from the steel element joint may enter the ground on the front surface of the adjacent steel element, and may become an obstacle during excavation.
[0042]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the problem to be solved by the present invention is to provide an opening closing member for a steel element joint that can be easily dropped when a steel element is inserted, and a steel element. It is to provide a method for protecting the joint opening.
[0043]
[Means for Solving the Problems]
In order to solve the above problems, the opening closing member of the steel element joint according to the present invention is:
Two protrusions which are provided along the element axial direction at appropriate portions of a steel element having an appropriate cross section and extending in the element axial direction, and constitute a fitting portion having a substantially “C” -shaped cross section. A steel element joint that has a portion and joins adjacent steel elements by mutual fitting of the fitting portions, and transmits a force in a direction perpendicular to the element axis that is perpendicular to the element axial direction An opening closing member for closing an opening of a fitting groove formed between the two protrusions of
The opening closing member is made of an elastic material, and includes a closing portion that fits and closes at least the opening of the fitting groove, and a base that connects to the closing portion, and the inside of the fitting groove When the pressing force toward the outside of the opening is applied, the closing portion is deformed and pushed outward of the opening so that the opening closing member can be detached from the steel element joint. It is characterized by that.
[0044]
In the opening closing member of the steel element joint described above, preferably, the closing portion is fitted and closed to a part of the fitting groove that communicates with the opening and the opening, Two groove portions are formed on both sides of the deformation-absorbing recess by providing a groove-shaped deformation-absorbing recess at the approximate center of the groove-opposite surface, which is the surface facing the innermost portion of the fitting groove, When a pressing force is applied from the inside of the fitting groove to the outside of the opening, the two protruding strips are deformed so as to approach each other, and the closing portion is pushed out of the opening. The opening closing member is configured to be removable from the steel element joint.
[0045]
Further, in the opening closing member of the steel element joint described above, preferably, the closing portion is fitted and closed in the opening of the fitting groove, connected to the base portion, and the steel element joint. A tongue-like portion that is bonded to the outside of one of the two projecting portions; a pressing force is applied from the inside of the fitting groove toward the outside of the opening portion; When the opening closing member is pushed out of the opening and falls off the steel element joint, it moves into the ground outside the region of the steel element.
[0046]
Further, in the opening closing member of the steel element joint described above, preferably,
A groove back facing surface that is a surface facing the innermost part of the fitting groove in the closing portion has a first taper surface that is a part or all of the inclined surface, and the opening closing member. Is attached to the steel element joint, the protrusion height from the base at the first end which is the end of the first tapered surface on the side where the protrusion of the other steel element joint is inserted The height of the protrusion from the base increases with increasing distance from the first end in the element axial direction, and is a second end opposite to the first end of the first tapered surface. At the end, the protrusion height from the base is set to be maximum,
When the protruding portion of the other steel element joint is inserted into the fitting groove, a pressing force is applied to the closing portion of the opening closing member from the inside of the fitting groove toward the outside of the opening portion. Is set to occur.
[0047]
In the opening closing member of the steel element joint described above, preferably, the direction in which the opening closing member drops from the steel element joint is adjusted by appropriately setting the inclination direction of the first tapered surface. .
[0048]
In the opening closing member of the steel element joint described above, preferably, the first tapered surface is inclined substantially along the element axial direction.
[0049]
Moreover, in the opening obstruction | occlusion member of an above-described steel element joint, Preferably, the said base part is provided with two groove-shaped fitting recessed parts fitted to the said 2 protrusion part of the said steel element joint.
[0050]
Moreover, the protection method of the opening part of the steel element joint according to the present invention is:
Two protrusions which are provided along the element axial direction at appropriate portions of a steel element having an appropriate cross section and extending in the element axial direction, and constitute a fitting portion having a substantially “C” -shaped cross section. A steel element joint that has a portion and joins adjacent steel elements by mutual fitting of the fitting portions, and transmits a force in a direction perpendicular to the element axis that is perpendicular to the element axial direction A method of protecting an opening of a fitting groove formed between the two protrusions with an opening closing member,
The opening closing member is formed of an elastic material, and includes a closing portion that fits and closes at least the opening of the fitting groove, and a base connected to the closing portion,
Before inserting the projecting portion into the fitting groove, the fitting groove and the closing portion are fitted, and the opening closing member is slid in the element axial direction, so that the steel element Attach the opening closing member to the joint, prevent foreign matter from entering from the opening,
When inserting the projecting portion into the fitting groove, a pressing force is generated on the closing portion from the inside of the fitting groove to the outside of the opening portion, so that the two ridges are mutually connected. Deforming to approach, pushing the closing part outwardly of the opening and dropping the opening closing member from the steel element joint
It is characterized by.
[0051]
In the above-described method for protecting the opening of the steel element joint, the insertion end surface, which is the surface of the end portion to be inserted into the fitting groove, of the projecting portion is preferably a flat surface inclined partly or entirely. When the protrusion is inserted into the fitting groove, the closing portion of the opening closing member is connected to the outside of the opening from the inside of the fitting groove. It is set so that a pressing force toward the direction is generated.
[0052]
In the above-described method for protecting the opening of the steel element joint, preferably, the direction in which the opening blocking member is dropped from the steel element joint is set by appropriately setting the inclination direction of the second tapered surface. adjust.
[0053]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0054]
(1) First embodiment
FIG. 1 is a diagram showing a configuration of a dummy joint of a steel element joint according to a first embodiment of the present invention, FIG. 1 (A) is an overall perspective view, and FIG. 1 (B) is a steel element joint. FIG. 1 shows a cross-sectional view (a cross-sectional view in the vicinity of the right end of FIG. 1A) in a state where it is mounted on each. Moreover, FIG. 2 is another figure which shows the structure of the dummy joint of the steel element joint shown in FIG. 1, and is the whole perspective view seen from the back surface of the base. FIG. 3 is a cross-sectional view taken along line AA showing the configuration of the dummy joint of the steel element joint shown in FIG.
[0055]
As shown in FIGS. 1 to 3, the dummy joint 1 of the first embodiment corresponds to the opening closing member in the claims, and is a member made of an elastic material and formed in a substantially columnar shape. The dummy joint 1 is of a type that is attached to a joint 13 of a steel element, and includes a fitting portion 1a and a base portion 1b that is connected to the back of the fitting portion 1a. Moreover, the fitting part 1a has the obstruction | occlusion part 1c.
[0056]
Examples of the elastic material include rubber materials and soft plastics materials. Among these, the rubber-based material includes natural rubber, artificial rubber, and composite material using rubber. Examples of the soft plastics material include soft materials among so-called synthetic resin materials, and composite materials using plastics such as FRP (Fiber Reinforced Plastics).
[0057]
The closing part 1c is a part protruding from the base part 1b. The closed portion 1c includes a portion that fits into an opening 13e2 formed between the two protruding portions 13c and 13d in the internal space 13e1 of the fitting groove 13e of the joint 13 of the steel element, and an opening 13e2. There is a portion that fits into a part of the internal space 13e1 that communicates with the internal space 13e1. As a result, the opening 13e2 is closed. Moreover, the height in the figure of the part fitted to a part of the internal space 13e1 communicating with the opening 13e2 in the closed part 1c is set to a value larger than the height in the figure of the part fitted in the opening 13e2. The former has a swelled cross section than the latter.
[0058]
In the closed portion 1c, a groove-shaped deformation-absorbing concave portion is provided at the approximate center of a surface (hereinafter, referred to as a “groove back facing surface”) 1c1 that faces the innermost portion 13e3 of the fitting groove 13e of the steel element joint 13. 1c2 is provided. The cross section of the groove-like recess of the deformation absorbing recess 1c2 is substantially “V” -shaped. By providing the deformation absorbing recess 1c2, two ridges 1c3 and 1c4 are formed on both sides of the deformation absorbing recess 1c2. The base 1b is provided with two groove-like fitting recesses 1d1 and 1d2 that fit into the two protrusions 13c and 13d of the steel element joint 13.
[0059]
Further, the groove back facing surface 1c1, which is the surface of the closing portion 1c, has a first tapered surface 1g, which is an inclined plane, at a part thereof (near the left end in FIG. 1A). The first tapered surface 1g is inclined substantially along the element axial direction (the direction connecting the front and back of the paper surface in FIG. 1B).
[0060]
Further, as shown in FIGS. 1 (A) and 3, the first tapered surface 1g is inserted into the protruding portion of another steel element joint when the opening closing member 1 is mounted on the steel element joint. The first end portion 1g1 that is the end portion of the first tapered surface on the side to be received has the minimum protrusion height from the base portion 1b, and the protrusion height from the base portion 1b as the distance from the first end portion 1g1 increases in the element axial direction. In the second end 1g2, which is the end opposite to the first end 1g1 of the first tapered surface 1g, the protrusion height from the base 1b is set to be maximum.
[0061]
In FIG. 1A, the longitudinal direction of the dummy joint 1, that is, the oblique left and right direction in the drawing is parallel to the element axis direction. In FIG. 3, the vertical direction in the drawing is parallel to the element axis direction.
[0062]
Next, the effect | action of the above-mentioned dummy joint 1 is demonstrated in detail, referring FIG.4 and FIG.5.
[0063]
4A and 4B are diagrams showing a configuration of a jig for removing the dummy joint of the steel element joint shown in FIG. 1. FIG. 4A is a cross-sectional view, and FIG. The top view of a part is shown, respectively.
[0064]
The dummy joint removing jig 33 is attached to the tip of the steel element joint. The cross-section of the jig 33 is the same as that of the steel element joint, and as shown in FIG. 4C, a substantially “C” -shaped fitting portion 33a and a base portion 33b connected to the back of the fitting portion 33a. have. Moreover, the fitting part 33a has the two protrusion parts 33c and 33d. The tip of the protrusion 33c is enlarged in a bulb shape. Further, an intermediate portion between the projecting portion 33c and the projecting portion 33d is a fitting groove 33e having a substantially elliptical cross section and extending in the element axial direction.
[0065]
As shown in FIG. 4B, the insertion end surface, which is the surface of the end portion of the protruding portion 33c, is a second tapered surface 33g that is an inclined plane. In FIG. 4B, the vertical direction in the figure is parallel to the element axis direction. The direction of the inclined surface of the second taper surface 33g and the direction of the inclined surface of the first taper surface 1g are set to be parallel to each other when the element axis directions are aligned in the same direction. Yes.
[0066]
With the configuration as described above, the protrusion 33c of the dummy joint removal jig 33 is inserted into the fitting groove 13e of the joint 13 shown in FIG. The second tapered surface 33g of the dummy joint removing jig 33 is in close contact with the first tapered surface 1g of the dummy joint 1 attached to the joint 13.
[0067]
Thereafter, when the protrusion 33c of the dummy joint removing jig 33 is further slid into the fitting groove 13e of the joint 13 shown in FIG. The second taper surface 33g of the joint removing jig 33 presses the groove back facing surface 1c1 and the closing portion 1c of the dummy joint 1 in the direction from the inner space 13e1 of the fitting groove 13e toward the outside of the opening 13e2. . That is, in FIG. 1B, a pressing force from the right to the left in the figure is applied to the groove back facing surface 1c1 and the closing portion 1c.
[0068]
The direction of the pressing force is a direction inclined slightly forward with respect to the element axis direction rather than the direction perpendicular to the element axis. This is because the force acts in the direction of the normal of the surface. Therefore, the direction in which the dummy joint 1 drops off from the steel element joint 13 can be adjusted by appropriately setting the inclination direction of the surface of the first tapered surface 1g. The same can be said for the second tapered surface 33g, and the direction in which the dummy joint 1 drops from the steel element joint 13 is adjusted by appropriately setting the inclination direction of the second tapered surface 33g. It is possible.
[0069]
As described above, the deformation absorbing recess 1c2, which is a groove-shaped recess having a substantially “V” -shaped cross section, is formed at the approximate center of the groove back facing surface 1c1, which is the surface of the closing portion 1c. For this reason, when the above pressing force is received, as shown in FIG. 5A, the two ridges 1c3 and 1c4 of the closing portion 1c are deformed so as to approach each other around the deformation absorbing recess 1c2. Ultimately, the deformation absorbing recess 1c2 disappears due to this deformation, and the two ridges 1c3 and 1c4 are brought into close contact with each other. In this state, the combined thickness of the two ridges 1c3 and 1c4 decreases and approaches the value of the opening 13e2 of the joint 13. That is, if the above pressing force is further applied, the entire closing portion 1c is elastically deformed and contracted, and can be easily detached from the opening 13e2 of the joint 13.
[0070]
Accordingly, when the protrusion 33c of the dummy joint removing jig 33 is further slid into the fitting groove 13e of the joint 13 shown in FIG. 1B, the above pressing force is further applied. As shown in FIG. 5 (B), the entire closing portion 1c is pushed outward from the opening 13e2 of the joint 13.
[0071]
That is, after that, when the protrusion 33c of the dummy joint removing jig 33 is further slid into the fitting groove 13e of the joint 13 shown in FIG. The whole 1c is pushed outward from the opening 13e2 of the joint 13. Thereby, finally, the dummy joint 1 falls off to the outside in the lateral direction of the steel element joint 13.
[0072]
According to the dummy joint (opening closing member of the steel element joint) 1 of the first embodiment described above, as in the case of the conventional dummy joint 200, foreign matter is introduced from the opening 13e2 of the fitting groove 13e of the steel element joint 13. It can be protected from entering, and has the following advantages over the conventional dummy joint 200.
[0073]
a) The dummy joint 1 of the present embodiment is easily removed from the joint 13 and the like by simply inserting the subsequent steel element, fitting the steel element joints to each other, and sliding them. A large force is not required for pushing, and the cost required for the device for pushing can be reduced.
[0074]
b) Moreover, even if the ground is hard, a situation in which the dummy joint resists the insertion of the steel element does not occur, and the workability of the steel element method is improved.
[0075]
c) Since the direction in which the dummy joint drops off from the steel element joint can be adjusted appropriately by appropriately setting the inclination direction of each tapered surface 1g or 33g, the dummy joint deviated from the steel element joint However, it is possible to prevent such a situation that it enters into the ground in front of the adjacent steel element and becomes an obstacle during excavation.
[0076]
(2) Second embodiment
The present invention can also be realized by configurations other than the first embodiment described above. FIG. 6 is a diagram showing a configuration of a dummy joint of a steel element joint according to a second embodiment of the present invention, and is a cross-sectional view in a state where the steel element joint is mounted.
[0077]
The dummy joint 2 of the second embodiment corresponds to the opening closing member in the claims, and is a member made of an elastic material and formed in a substantially columnar shape. The dummy joint 2 is of a type that is mounted on a steel element joint 23, and includes a fitting portion 2a and a base portion 2b that is connected to the back of the fitting portion 2a. Moreover, the fitting part 2a has the obstruction | occlusion part 2c.
[0078]
As said elastic material, rubber-type material, a soft plastics material, etc. are contained like the case of 1st Embodiment.
[0079]
The blocking part 2c is a part protruding from the base part 2b. The closed portion 2c includes a portion that fits into the opening 23e2 formed between the two protruding portions 23c and 23d in the inner space 23e1 of the fitting groove 23e of the joint 23 of the steel element, and the opening 23e2. There is a portion that fits into a part of the internal space 23e1 that communicates with the internal space 23e1. As a result, the opening 23e2 is closed. In addition, the height of the portion of the closed portion 2c that fits into a part of the internal space 23e1 that communicates with the opening 23e2 is set to a value that is larger than the height of the portion that fits into the opening 23e2. The former has a swelled cross section than the latter.
[0080]
In the closed portion 2c, a groove-shaped deformation-absorbing concave portion is provided at the approximate center of a surface (hereinafter, referred to as “groove depth facing surface”) 2c1 that faces the innermost portion 23e3 of the fitting groove 23e of the steel element joint 23. 2c2 is provided. The cross section of the groove-shaped recess of the deformation absorbing recess 2c2 is substantially “V” -shaped. By providing the deformation absorbing recess 2c2, two ridges 2c3 and 2c4 are formed on both sides of the deformation absorbing recess 2c2. The base 2b is provided with two groove-like fitting recesses 2d1 and 2d2 that fit into the two protrusions 23c and 23d of the steel element joint 23.
[0081]
Moreover, although not shown in figure, the groove | channel back opposing surface 2c1 which is the surface of the obstruction | occlusion part 2c has the 1st taper surface which is the inclined plane which has the same structure as the case of 1st Embodiment.
[0082]
According to the dummy joint (opening closing member of the steel element joint) 2 of the above-described second embodiment, as in the case of the conventional dummy joint 200, foreign matter is introduced from the opening 23e2 of the fitting groove 23e of the steel element joint 23. It can protect from entering, and has the same advantages as the dummy joint 1 of the first embodiment described above.
[0083]
(3) Third embodiment
The present invention can also be realized by configurations other than the first and second embodiments described above. FIG. 7: is a figure which shows the structure of the dummy joint of the steel element coupling which is 3rd Embodiment of this invention, Comprising: It is sectional drawing in the state with which the steel element coupling was mounted | worn.
[0084]
The dummy joint 3 of the third embodiment corresponds to the opening closing member in the claims, and is a member made of an elastic material and formed in a substantially columnar shape. The dummy joint 3 is of a type that is attached to a joint 23 of a steel element, and includes a fitting portion 3a, a base portion 3b that is connected to the back of the fitting portion 3a, and a tongue that is connected to the upper portion of the base portion 3b in the drawing. 3h and the joint adhesion part 3i are comprised. Moreover, the fitting part 3a has the obstruction | occlusion part 3c. Unlike the dummy joints 1 and 2 of the first and second embodiments described above, the dummy joint 3 of the third embodiment does not have the deformation absorbing recess 1c2 or 2c2.
[0085]
As said elastic material, rubber-type material, a soft plastics material, etc. are contained like the case of 1st Embodiment.
[0086]
The blocking part 3c is a part protruding from the base part 3b. The closing portion 3c has only a portion that fits into the opening 23e2 formed between the two protruding portions 23c and 23d in the internal space 23e1 of the fitting groove 23e of the joint 23 of the steel element. Yes. This portion closes the opening 23e2.
[0087]
Moreover, although not shown in figure, the groove | channel back opposing surface 3c1 which is the surface of the obstruction | occlusion part 3c has the 1st taper surface which is an inclined plane which has the same structure as the case of 1st Embodiment.
[0088]
The tongue-shaped portion 3h is a curved plate-shaped portion and is connected to the upper portion of the base portion 3b. The tongue 3h may be formed integrally with the base 3b or the like when the dummy joint 3 of the third embodiment is manufactured, or the tongue 3h is manufactured as an independent member different from the base 3b or the like. However, it may be formed by bonding with an adhesive or the like at the joint portion 3k which is the upper portion of the base portion 3b.
[0089]
The joint bonding portion 3i is a portion provided on the lower surface near the right end in the drawing of the tongue-shaped portion 3h, and is formed by application of an adhesive or the like. The dummy joint 3 is attached to the vicinity of the outer upper surface of the steel element joint 23 by the joint bonding portion 3i.
[0090]
According to the above-described dummy joint (opening closing member of the steel element joint) 3 of the third embodiment, as in the case of the conventional dummy joint 200, foreign matter is introduced from the opening 23e2 of the fitting groove 23e of the steel element joint 23. In addition to having the same advantages as the dummy joint 1 of the first embodiment described above, there are the following advantages.
[0091]
d) In the dummy joint 3 of the present embodiment, the vicinity of the front end (left end in FIG. 7) of the blocking portion 3c is not inflated. Therefore, it is possible to drop the steel element joints 13 and 23 more easily than the dummy joints 1 and 2 simply by inserting the subsequent steel elements, fitting the steel element joints and sliding them. Is possible.
[0092]
e) Further, in the dummy joint 3 of the present embodiment, the lower end surface of the tongue-shaped portion 3h is bonded to the outer upper surface of the steel element joint 23 and the like by the joint bonding portion 3i. For this reason, even if the blocking portion 3c receives a pressing force in the direction from the left to the right in FIG. 7 (hereinafter referred to as “dummy joint drop-off direction”) for some reason, this joint bonding portion. 3i prevents the tongue-shaped portion 3h from shifting in the dummy joint drop-off direction. Thereby, the dummy joint 3 of this embodiment cannot be easily removed from the opening 23e2 of the steel element joint 23 before the joint of the subsequent steel element is inserted.
[0093]
f) Furthermore, in the dummy joint 3 of the present embodiment, the lower end surface of the tongue-shaped portion 3h is bonded to the outer upper surface of the steel element joint 23 and the like by the joint bonding portion 3i. For this reason, in the dummy joint 3, the joint adhesion portion 3 i functions as a “hinge”. Accordingly, after the dummy joint 3 is detached from the steel element joint 23 and the like, it rotates counterclockwise in FIG. 7 and moves to the ground outside the region of the steel element. Therefore, it does not become an obstacle when excavating the ground in front of the steel element.
[0094]
The present invention is not limited to the above embodiments. Each of the embodiments described above is an exemplification, and any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and has the same operational effects can be used. It is included in the technical scope of the present invention.
[0095]
For example, in each of the above embodiments, the steel element is inserted substantially vertically downward, and for example, an opening blocking member (for example, dummy joint 1 or 2) of the steel element joint in the case of constructing an underground continuous wall, and the like, and The method for protecting the opening of the steel element joint has been described as an example, but the present invention is not limited to this, and other types of steel element construction methods, for example, the steel element is directed in a substantially horizontal direction. For example, the present invention can be applied to a case where a box-shaped structure or the like is inserted in the basement.
[0096]
Moreover, in each said embodiment, although the 1st taper surface (for example, 1g) demonstrated the example formed in a part of groove | channel back opposing surface (for example, 1c1), this invention is limited to this. Instead, the first taper surface may be formed on other configurations, for example, all of the groove depth facing surface. The same applies to the second tapered surface (for example, 33 g), and the second tapered surface may form the second tapered surface on the entire insertion end surface of the jig 33.
[0097]
In the first and second embodiments described above, the shape of the upper end or the lower end of the cross-section of the protruding portion (for example, 1c3 and 1c4, 2c3 and 2c4) of the closing portion is as shown in FIG. Further, although an example in which the corner has an acute angle has been described, the present invention is not limited to this, and other configurations, for example, the projection of the blocking portion 4c as in the dummy joint 4 shown in FIG. The shape near the upper end of the cross section of the strip 4c3 and the shape of the lower end of the cross section of the convex strip 4c4 may be configured to be a smooth curved surface. In this way, when the pressing force is further applied after the state similar to that shown in FIG. 5A, the entire opening closing member (for example, the dummy joint 4) can be easily dropped.
[0098]
In FIG. 8, the dummy joint 4 corresponds to the opening closing member in the claims, and is a member made of an elastic material and formed in a substantially columnar shape. This dummy joint 4 is of a type that is attached to a joint 23 of a steel element, and includes a fitting portion 4a and a base portion 4b that is connected to the back of the fitting portion 4a. Moreover, the fitting part 4a has the obstruction | occlusion part 4c. As said elastic material, rubber-type material, a soft plastics material, etc. are contained like the case of 1st Embodiment.
[0099]
The blocking part 4c is a part protruding from the base part 4b. The closing portion 4c includes a portion that fits into an opening 23e2 formed between the two protruding portions 23c and 23d in the internal space 23e1 of the fitting groove 23e of the joint 23 of the steel element, and an opening 23e2. There is a portion that fits into a part of the internal space 23e1 that communicates with the internal space 23e1. As a result, the opening 23e2 is closed. Moreover, the height in the figure of the part fitted to a part of internal space 23e1 connected to the opening part 23e2 among the obstruction | occlusion parts 4c is set to a larger value than the height in the figure of the part fitted to the opening part 23e2. The former has a swelled cross section than the latter.
[0100]
In the closed portion 4c, a groove-shaped deformation-absorbing concave portion is provided at a substantially center of a surface (hereinafter referred to as a “groove depth facing surface”) 4c1 that faces the innermost portion 23e3 of the fitting groove 23e of the steel element joint 23. 4c2 is provided. The cross section of the groove-shaped recess of the deformation absorbing recess 4c2 is substantially “V” -shaped. By providing the deformation absorbing recess 4c2, two ridges 4c3 and 4c4 are formed on both sides of the deformation absorbing recess 4c2. The base portion 4b is provided with two groove-like fitting recesses 4d1 and 4d2 that fit into the two protrusions 23c and 23d of the steel element joint 23.
[0101]
Moreover, although not shown in figure, the groove | channel back opposing surface 4c1 which is the surface of the obstruction | occlusion part 4c has the 1st taper surface which is an inclined surface which has the same structure as the case of 1st Embodiment.
[0102]
According to the dummy joint (opening closing member of the steel element joint) 4 of the other embodiment described above, foreign matter is introduced from the opening 23e2 of the fitting groove 23e of the steel element joint 23 as in the conventional dummy joint 200. In addition to the above-mentioned advantages (the point that the entire dummy joint 4 can be easily dropped by applying a pressing force after the same state as in FIG. 5A). This has the same advantages as the dummy joint 1 of the first embodiment.
[0103]
【The invention's effect】
As described above, according to the present invention, as an opening closing member for closing the opening of the fitting groove formed between the two protrusions of the steel element joint,
A groove formed of an elastic material, mainly including a closed portion that is fitted and closed in the opening portion of the fitting groove, and a base portion that is connected to the closed portion, and facing the innermost portion of the fitting groove in the closed portion By providing a groove-shaped deformation absorbing recess at the approximate center of the rear facing surface, two ridges are formed on both sides of the deformation absorbing recess, so that the push from the inside of the fitting groove toward the outside of the opening is performed. When pressure is applied, the two ridges are deformed so as to approach each other, the closing part is pushed out of the opening, and the opening closing member can be detached from the steel element joint. Thereby, it has the following advantages.
[0104]
Since the opening closing member of the present invention can be easily detached from the steel element joint simply by inserting the subsequent steel element, a large force is not required for pushing the steel element, The cost required for the apparatus can be reduced.
[0105]
Moreover, even if the ground is hard, the situation where the opening blocking member resists the insertion of the steel element does not occur, and the workability of the steel element method is improved.
[0106]
In addition, by appropriately setting the direction of inclination of the first taper surface or the second taper surface, the direction in which the opening closing member is detached from the steel element joint can be adjusted appropriately, so that the first taper surface or the second taper surface deviated from the steel element joint. A situation in which the opening closing member enters the ground on the front surface of the adjacent steel element and becomes an obstacle during excavation is prevented.
[Brief description of the drawings]
1A and 1B are diagrams showing a configuration of a dummy joint of a steel element joint according to a first embodiment of the present invention. FIG. 1A is an overall perspective view, and FIG. 1B is a steel element joint. FIG. 1 shows a cross-sectional view (a cross-sectional view in the vicinity of the right end of FIG. 1A) in a state where it is mounted on each.
2 is another view showing the configuration of the dummy joint of the steel element joint shown in FIG. 1, and is an overall perspective view seen from the back of the base.
3 is a cross-sectional view taken along line AA showing a configuration of a dummy joint of the steel element joint shown in FIG. 1. FIG.
4 is a diagram showing a configuration of a jig for removing a dummy joint of the steel element joint shown in FIG. 1, wherein FIG. 4 (A) is a sectional view and FIG. 4 (B) is a view from above. The top view of a part is shown, respectively.
FIG. 5 is a view for explaining the operation of the dummy joint of the steel element joint shown in FIG. 1;
FIG. 6 is a view showing a configuration of a dummy joint of a steel element joint according to a second embodiment of the present invention, and is a cross-sectional view in a state where the steel element joint is mounted.
FIG. 7 is a diagram showing a configuration of a dummy joint of a steel element joint according to a third embodiment of the present invention, and is a cross-sectional view of the steel element joint attached to the steel element joint.
FIG. 8 is a view showing a configuration of a dummy joint of a steel element joint according to another embodiment of the present invention, and is a cross-sectional view in a state where it is mounted on a steel element joint.
FIG. 9 is a cross-sectional view showing a configuration of a reference pipe steel element used in a steel element type underground continuous wall construction method.
FIG. 10 is a cross-sectional view showing the configuration of a general steel element used in the steel element type underground continuous wall construction method.
11 is a perspective view showing a configuration of a general steel element shown in FIG.
FIG. 12 is a cross-sectional view showing a joining state of a reference pipe steel element and a general steel element.
FIG. 13 is a cross-sectional view showing a configuration of a conventional dummy joint.
[Explanation of symbols]
1 Dummy joint
1a Fitting part
1b Base
1c Blocking part
1c1 Groove back facing surface
1c2 Deformation absorbing recess
1c3, 1c4 ridge
1d1, 1d2 Fitting recess
1g First taper surface
1g1 first end
1g2 second end
2 Dummy joint
2a Fitting part
2b base
2c Blocking part
2c1 Groove depth facing surface
2c2 Deformation absorbing recess
2c3, 2c4 ridge
2d1,2d2 fitting recess
3 Dummy joint
3a Fitting part
3b base
3c Blocking part
3c1 Groove depth facing surface
3d1, 3d2 fitting recess
3h Tongue
3i Joint bonding part
3k joint
4 Dummy joint
4a Fitting part
4b base
4c Blocking part
4c1 Groove depth facing surface
4c2 Deformation absorbing recess
4c3, 4c4 ridge
4d1, 4d2 Fitting recess
10 Reference pipe steel element
11, 12 Steel plate-like member
13 Fitting
13a Fitting part
13b base
13c, 13d Projection
13e Mating groove
13e1 interior space
13e2 opening
13e3 innermost part
20 General steel element
21, 22 Steel plate-like member
23 Fitting
23a Fitting part
23b base
23c, 23d Projection
23e Mating groove
33 Dummy joint removal jig
33a Fitting part
33b Base
33c, 33d Projection
33e Mating groove
33g Second taper surface
200 dummy joint
200a Fitting part
200b base
200c, 200d Protruding part
200e Fitting groove
W weld

Claims (10)

Two protrusions which are provided along the element axial direction at appropriate portions of a steel element having an appropriate cross section and extending in the element axial direction, and constitute a fitting portion having a substantially “C” -shaped cross section. A steel element joint that has a portion and joins adjacent steel elements by mutual fitting of the fitting portions, and transmits a force in a direction perpendicular to the element axis that is perpendicular to the element axial direction An opening closing member for closing an opening of a fitting groove formed between the two protrusions of
The opening closing member is made of an elastic material, and includes a closing portion that fits and closes at least the opening of the fitting groove, and a base that connects to the closing portion, and the inside of the fitting groove When the pressing force toward the outside of the opening is applied, the closing portion is deformed and pushed out to the outside of the opening so that the opening closing member can be detached from the steel element joint. An opening closing member for a steel element joint. In the opening closing member of the steel element joint according to claim 1,
The closing portion is a groove which is a surface facing the innermost portion of the fitting groove in the closing portion, and is fitted and closed to a part of the fitting groove communicating with the opening and the opening. By providing a groove-shaped deformation absorbing recess at the approximate center of the rear facing surface, two ridges are formed on both sides of the deformation absorbing recess, and the push toward the outside of the opening from the inside of the fitting groove is formed. When pressure is applied, the two ridges are deformed so as to approach each other, the closing part is pushed out of the opening, and the opening closing member can be detached from the steel element joint. An opening closing member for a steel element joint, characterized in that it is configured. In the opening closing member of the steel element joint according to claim 1,
The closing portion is fitted and closed in the opening of the fitting groove, is connected to the base portion, and is attached to the outside of one of the two protruding portions of the steel element joint. A pressing force is applied from the inside of the fitting groove to the outside of the opening, the closing portion is deformed and pushed outward of the opening, and the opening closing member is made of the steel element. An opening closing member for a steel element joint, which moves to the ground outside the region of the steel element when it is dropped from the joint. In the opening closing member of the steel element joint according to claim 2 or 3,
A groove back facing surface that is a surface facing the innermost part of the fitting groove in the closing portion has a first taper surface that is a part or all of the inclined surface, and the opening closing member. Is attached to the steel element joint, the protrusion height from the base at the first end which is the end of the first tapered surface on the side where the protrusion of the other steel element joint is inserted The height of the protrusion from the base increases with increasing distance from the first end in the element axial direction, and is a second end opposite to the first end of the first tapered surface. At the end, the protrusion height from the base is set to be maximum,
When the protruding portion of the other steel element joint is inserted into the fitting groove, a pressing force is applied to the closing portion of the opening closing member from the inside of the fitting groove toward the outside of the opening portion. An opening closing member for a steel element joint, wherein In the opening closing member of the steel element joint according to claim 4,
An opening closing member for a steel element joint, wherein a direction in which the opening closing member is dropped from the steel element joint is adjusted by appropriately setting an inclination direction of the first tapered surface. In the opening closing member of the steel element joint according to claim 4,
The opening closing member of the steel element joint, wherein the first tapered surface is inclined substantially along the element axial direction. In the opening closing member of the steel element joint according to claim 1,
An opening closing member for a steel element joint, wherein the base is provided with two groove-like fitting recesses that fit into the two protrusions of the steel element joint. Two protrusions which are provided along the element axial direction at appropriate portions of a steel element having an appropriate cross section and extending in the element axial direction, and constitute a fitting portion having a substantially “C” -shaped cross section. A steel element joint that has a portion and joins adjacent steel elements by mutual fitting of the fitting portions, and transmits a force in a direction perpendicular to the element axis that is perpendicular to the element axial direction A method of protecting an opening of a fitting groove formed between the two protrusions with an opening closing member,
The opening closing member is formed of an elastic material, and includes a closing portion that fits and closes at least the opening of the fitting groove, and a base connected to the closing portion,
Before inserting the projecting portion into the fitting groove, the fitting groove and the closing portion are fitted, and the opening closing member is slid in the element axial direction, so that the steel element Attach the opening closing member to the joint, prevent foreign matter from entering from the opening,
When inserting the projecting portion into the fitting groove, a pressing force is generated on the closing portion from the inside of the fitting groove to the outside of the opening portion, so that the two ridges are mutually connected. A method for protecting an opening of a steel element joint, wherein the opening is pushed out of the opening and the opening closing member is dropped from the steel element joint. In the protection method of the opening part of the steel element coupling according to claim 8,
An insertion end surface which is a surface of an end portion inserted into the fitting groove in the protrusion has a second tapered surface which is a flat surface inclined in part or in whole, and the inside of the fitting groove. When the projecting portion is inserted into the opening closing member, the closing portion of the opening closing member is set to generate a pressing force from the inside of the fitting groove toward the outside of the opening. To protect the opening of the steel element joint. In the protection method of the opening part of the steel element joint according to claim 9,
A method for protecting an opening of a steel element joint, wherein a direction in which the opening closing member is dropped from the steel element joint is adjusted by appropriately setting an inclination direction of the second tapered surface.

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