JP2001348894A - Construction method for retaining wall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To construct a retaining wall using a low-cost post in place of a strong, high-cost post heretofore required since the post is bent by side pressure from the filler side when fixing wall surface form panels erected in a breaking joint form, to the post in the rear in the horizontal state of connecting members of a connecting fixture and filling the filler on the back side to construct the retaining wall. SOLUTION: A vertical fixing member 12 of a connecting fixture 11 for fixing the wall surface form panels 1, 1 in the upper and lower stages of a breaking joint is provided with an obliquely upward connecting member 13 and an obliquely downward connecting member 14, and the respective rear end parts of both connecting members 13, 14 are fixed in truss structure to a post 31 formed of a low-cost round steel bar or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wall panel having a fixed size (sometimes simply referred to as a panel).
Are arranged vertically in the left and right direction to form a lower row, and the same panel is arranged on the lower row by shifting the width by half the width in the left and right direction to form an upper row. Filling the back side of the row of wall panels with concrete, cement, sand, water, slurry-type air mortar with foaming agent, filler such as earth and sand, gravel, etc., use the panel as a formwork when filling the filler The present invention also relates to a method for constructing a retaining wall after filling, which is used as a decorative wall of the retaining wall.

[0002]

2. Description of the Related Art On a foundation on which columns are erected at predetermined intervals in the left-right direction, 1 / one of the width of the panel is provided in front of the columns.
Panels with hooks and other engaging parts protruding from the upper and lower positions on the back side shifted inward from the left and right ends by 4 are lined up in a line in the left and right direction, and the same panel is shifted by 1/2 of the width on the left and right. And the lower part of the vertical fixing member of the connecting fixture is attached to the upper engaging part of the lower panel, and the lower engaging part of the upper panel is placed above the fixing member. And fix the upper and lower panels at the break joint. In this manner, the same panel is halved by the fixing member of the connecting fixture on the panels arranged in a line in the left-right direction.
Repeating this process, the rear end of the connecting member having one end attached to the fixing member of each of the connecting fixtures is fixed to the column. After that, the applicant of the present invention applied a method for constructing a retaining wall by filling the above-mentioned filler on the back side of the vertically arranged multi-stage panel to construct a retaining wall.
-4496, and Japanese Patent Application No. 11-23649.

[0003]

SUMMARY OF THE INVENTION The aforementioned Japanese Patent Application No. 11-23 / 1990
In Japanese Patent No. 649, as shown in FIG. 8, a connecting member having one end attached to a fixing member of a connecting fixture is horizontal, and a rear end portion is fixed to a column. In this case, the side pressure P of the filler acts on the panels in the uppermost row in the vertical arrangement, but since there is no resistance to the side pressure P in the rows of the panels in each vertical arrangement, the side pressure P is It is then transmitted to the column via the horizontal connecting member, and an excessive bending moment M = P × H acts on the base of the column, causing the column to bend. Therefore, it is necessary to use a strong structure for the support column so as not to bend against the bending moment, which increases the cost.

[0004]

SUMMARY OF THE INVENTION The present invention has been developed to solve the above-mentioned problems. In the above-mentioned retaining wall construction method, the wall form panels at the upper and lower steps of the connecting fixture are fixed. The vertical fixing member is provided with an obliquely upward connecting member and an obliquely downward connecting member, and the rear ends of the two connecting members are fixed to the support by a truss structure.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a wall form panel 1 used in the present invention, which is formed into a certain size with concrete or the like, and has a width (W) of 900 mm, a height of 300 mm, and the like.
It is a 35 mm-thick horizontally-long rectangle, and four hooks opened upward and downward such as U-shape and V-shape as engagement parts 2 from the top and bottom of the back side inward from each left and right end by 1/4 of the width. Protrude for a certain length. The upper two hooks and the lower two hooks are U-shaped at intervals of 450 mm between two upper and lower rebars 2 ′, 2 ′ embedded in the wall panel when forming the panel. , V-shaped so as to protrude from the rear surface of the panel by a predetermined amount.

FIG. 2A is a front view illustrating a first embodiment of a retaining wall construction method according to the present invention, and FIG.
FIG. 3 is a side view of the constructed retaining wall, and FIG. 4 shows two types of connecting fixtures 11 and 11 'used in the first embodiment.

The connecting fixture 11 shown in FIG. 4 (A) fits into the upper hook of the wall form panel 1 in which the lower portion 12d is arranged vertically, and the lower portion of the panel 1 which is arranged vertically in the upper portion 12u. A fixing member 12 made of a metal plate into which a hook on the side is fitted, and two rearward connecting members 13 and 14 having one ends fixed to the center in the vertical direction of the fixing member 12, one of the connecting members 13. Is obliquely upward and the other 14 is obliquely downward. The obliquely upward and obliquely downward angle α is about 45 ° with respect to the horizontal in the figure, but is not limited to 45 °.

A connecting fixture 11 'shown in FIG. 4 (B) comprises a metal plate fixing member 12' having only a lower portion 12d, and a rearward connecting member fixed at one end to the upper side of the fixing member 12 '. 16. This connecting fixture 11 '
Is used by fitting the lower portion 12d of the fixing member 12 'into the lower hook of the panel in the lowermost row of rows or by fitting it in the upper hook of the panel in the uppermost row. It is. The connecting member 16 of the connecting fixture 11 'used by fitting to the lower hook of the lowermost panel is inclined upward, and the connecting member 16 of the connecting fixture 11' used by fitting to the upper hook of the uppermost panel is used. Is turned obliquely downward.

The two connecting members 13, 1 of the connecting fixture 11
Reference numeral 4 denotes one end of the fixing member 12 which is attached to the center of the fixing member 12 in the vertical direction with bolts and nuts 15 and may be fastened with diagonally upward and diagonally downward, or welding without using bolts and nuts. May be fixed diagonally upward and diagonally downward. The connection fixture 11 ′ may be produced by welding one end of the connection member 16 to the upper side of the fixing member 12 ′ obliquely upward, or may be produced by welding obliquely downward. As shown in FIG. 4B, one end of the connecting member 16 is attached to the upper side of the fixing member 12 'with a bolt and a nut 15, and when the connecting member 16 is used for a hook below the lowermost panel, the connecting member 16 is connected. It is preferable that the connecting member 16 be fastened diagonally upward and used diagonally downward when used for hooks on the uppermost panel to eliminate directivity.

In order to construct the retaining wall shown in FIG. 2A, a foundation 21 is constructed by casting concrete on the ground, and at that time, a support 31 is provided on the foundation 21 in the left and right direction with the left and right hooks 2.
It is erected at the same interval of 450 mm as that of 2. Next, as shown in FIG. 3, the panel 1 in the lowermost row is erected on the foundation so that the upper and lower hooks 2 projecting from the back surface thereof are located right and left so as to be located in front of the columns 31. The lower part 1 of the connecting fixture 11 ′ is attached to the left and right two hooks 2 under the panel, respectively.
2d is fitted from above, and the connecting member 16 facing obliquely upward is
1 is fixed by welding or the like. The fixing members 1 of the connecting fixture 11 are respectively attached to the left and right two hooks 2 on each of the lowermost panels.
2, the lower part 12d is fitted from above, and the obliquely downward connecting member 14 is connected to the obliquely upward connecting member 16 of the connecting fixture 11 '.
And fixed on the support by welding or the like.
Also, the connecting member 13 that is obliquely upward is fixed to the same column by welding or the like, and the panel in the lowest row is erected on the foundation.

Next, the panel in the second row is shifted laterally by half of the horizontal width on the row of the lowermost panel shown in FIG. The lower part 12d is fitted to each of the two hooks, and the left and right two hooks below the second panel are attached to the upper part 12u of the fixing member 12 of each connecting fixture 11 projecting upward from the upper edge of the panel. Fit.
Also, the lower portions 12d of the fixing members of the connecting fixture 11 are respectively fitted from above to the two left and right hooks on each panel of the second stage shown in FIG. 14 is fixed on the support by a truss structure by, for example, welding to the support and intersecting with the connecting member 13 of the lower connecting member of the lower stage obliquely upward. In addition, the connecting member 13 that is inclined upward
Are fixed to the same column by welding or the like, and the second panel row is erected on the bottom panel row.

Then, the third panel row is erected on the second panel row shown in FIG. 2A by the above-described method while being shifted laterally by half of the horizontal width. The fourth row of panels is similarly erected above the row of panel panels by shifting the horizontal width again by １ ／ of the horizontal width. As a result, the odd-numbered panels such as the lowest row (first row) and the third row have the same arrangement, the second row,
The even-numbered panel such as the fourth row has the same arrangement as that of the odd-numbered panel, which is shifted by half the width of the panel.
The lower panel and the upper panel, such as the second and third rows, the second and third rows, constitute a break joint.

As a result, as shown in FIG. 3, the lower portions 12d are respectively fitted to the left and right hooks on the upper panel, and the lower left and right hooks of the upper panel are respectively connected to the upper portion 12u. The rear end of the obliquely upward connecting member 13 and the rear end of the obliquely downward connecting member 14, one end of which is fixed to the fixing member 12 for fixing the panels at the upper and lower stages, The truss structure is formed by welding, etc., to the column by intersecting the rear end of the diagonally downward connecting member 14 and the rear end of the diagonally upward connecting portion 13 of the upper and lower connecting fixtures for fixing the lower step on the column. Fixed at. Note that the distance between the support and the panel arranged in front of the support is set such that the rear end of the obliquely upward connecting member 13 and the rear end of the obliquely downward connecting member 14 intersect at the support. It is.

After the panels are erected on the foundation in about three or four steps, a filler 51 is filled between the erected panels and the shaved mountain slopes behind, and the filler is made of concrete or mortar. In the case of hardening, in the case of earth and sand, gravel, etc., after hardening, repeat the process of standing up three or four steps of panels and filling the filler material 51 to repeat the retaining wall of the required height. To construct.

Each time the filler 51 is filled, the rear end is fixed to the column 31 in a truss structure by the lateral pressure P of the filler applied to the upper end of the third or fourth row of the uppermost panel. Tensile force + P 'is applied to each connecting member 14 obliquely downward.
A compressive force -P 'acts on each of the connecting members 13 which are obliquely upward, whereby an upward tensile force + P is applied to the column 31 and a downward compressive force -P is applied to the three or four tiered panels. . Therefore, a large bending moment does not act on the root of the support on the upper surface of the foundation or on the position of the filler on the support.

FIG. 5A is a front view of a second embodiment for constructing a retaining wall according to the present invention, and FIG. 5B is a plan view of the same. Note that the side view of the retaining wall is the same as that of FIG. In this case, the pillars 31 are provided on the foundation 21 at an interval of the width (900 mm) of the wall form panel 1 in the left-right direction.
The left and right ends of the panel 1 have two columns 31, 31.
A and a panel in a row B which is shifted from the panels in the row A by a half of the horizontal width are alternately arranged in the vertical direction. The panel 1 in row B has a position (center) at half the width in front of one support 31.

For this reason, for example, the lower part 12d is fitted to the upper left hook of the lower row A panel, and the lower right hook of the upper row B panel is fitted to the upper part 12u to break the upper and lower panels. A connecting fixture (1) in which a diagonally upper left connecting member 13L and a diagonally lower left connecting member 14L are attached at the center of a vertical metal plate fixing member 12 fixed on the ground.
1L) is used. Also, the lower part 12d is fitted to the upper right hook of the lower row A panel, and the upper part B is fitted to the upper part 12u.
A vertical metal plate fixing member 12 for fitting the lower left hook of the row panel and fixing the upper and lower panel at the break joint
A connecting fixture (11R) to which a diagonally upper right connecting member 13R and a diagonally lower right connecting member 14R are attached is used in the central part of. Conversely, the lower part 12d is fitted to the upper left hook of the lower row B panel, the lower right hook of the upper row A panel is fitted to the upper part 12u, and the upper and lower panels are fixed at the break joint. A connecting fixture (11R) having a diagonally upper right connecting member 13R and a diagonally lower right connecting member 14R attached to the center of the metal plate fixing member 12 in the direction is used. Also, the lower part 1 is attached to the upper right hook of the lower row B panel.
2d, the lower left hook of the upper row A panel is fitted to the upper part 12u, and the upper and lower tier panels are fixed at the break joints. Connection member 13L and diagonally left-downward connection member 14
Use the connecting fixture (11L) to which L is attached.

The connecting member 13L of the connecting fixture (11L)
14L diagonally left, connecting member 1 of connecting fixture (11R)
The reason why the 3R and 14R are turned obliquely right is that there is a shift of 1/4 of the width of the panel in the left-right direction between the left and right hooks of the panel 1 and the support 31. , Each connecting member 13L, 14L, 13 obliquely downward
This is because the rear ends of the R and 14R cross each other and can be fixed. In addition, each connection member 13L, 14L, 13
The inclination angles of the R and 14R obliquely upward and obliquely downward with respect to the horizontal are arbitrary, but are approximately 45 ° in the figure, and these may be fixed to the center of the fixing member by fastening with bolts and nuts. Then, it may be fixed by welding.

It is not necessary to manufacture the connecting fixtures (11L) and (11R) separately, but one can also serve as the other. For example, the lower portion 12d of the fixing member 12 is fitted to the upper left hook of the lower row A (or row B) panel, and the lower right hook of the upper row B (or row A) panel is fitted to the upper portion 12u. Of the connecting fixture (11L) having the obliquely left-upward connecting member 13L and the obliquely left-downward connecting member 14L for fixing the panels at the upper and lower steps at the break joints by turning the upper and lower panels upside down. In this case, it becomes a connecting fixture (11R). That is, the 11L turned downward
Is the lower part of 11R. And 11L
This is because the obliquely left-upward connecting member 13L becomes the obliquely right-downward connecting member 14R of 11R, and the obliquely left-downward connecting member 14L of 11L becomes the obliquely right-upward connecting member 13R of 11R. Therefore, only one of the connection fixtures 11L and 11R needs to be manufactured.

In the case of the second embodiment, the lower portion 12d of the metal plate fixing member 12 'is fitted to the hook below the panel in the lowermost row, or the hook above the panel in the uppermost row. The connection fixing tool 11 ′ which is used by being fitted to the connection member includes a connection member 16 having a diagonally upper left direction, a connection member having a diagonally upper right direction,
Four types are required: a diagonally lower left direction and a diagonally lower right direction. However, the lower part 12 of the fixing member 12 '
If the connecting member is attached to the upper end of d by bolts and nuts, and the direction of the connecting member can be adjusted obliquely upward and obliquely downward, the direction of the connecting member can be obliquely upper left and obliquely lower left. 11′L, and 11′R that can be turned obliquely rightward and downward rightward.
Just kind.

On the foundation 21, for example, the row A of the first stage of the panel is arranged in front of the column 31, and the lower left portion 12 d of the connecting fixture 11 ′ is attached to the lower left hook of each panel.
Is fitted from above, the rear end of the connecting member 16L facing obliquely left and upward is fixed to the support by welding or the like, and the lower portion 12d of the connecting fixture 11'R is fitted onto the lower right hook from above, and the diagonally upper right is connected. The rear end of the member 16R is fixed to an adjacent column by welding or the like. The lower left portion 12d of the fixing member 12 of the connecting fixture 11 is fitted into the upper left hook from above, and the respective rear ends of the obliquely left-upward connecting member 13L and the obliquely left-downward connecting member 14L are welded to the column. Fix with. The rear end of the diagonally upper left connecting member 16L of the coupling fixture attached to the lower left hook and the rear end of the diagonally lower left coupling member 14L of the coupling fixture attached to the upper left hook are the same column. The truss structure is fixed by crossing over 90 °. or,
The lower part of the fixing member of the connecting fixture 11R is fitted into the upper right hook from above, and the rear ends of the diagonally upper right connecting member 13R and the diagonally lower right connecting member 14R are welded to the adjacent column by welding or the like. Fix it. Also in this case, the rear end of the diagonally upper right connecting member 16R of the coupling fixture attached to the lower right hook and the rear end of the diagonally lower right coupling member 14R of the coupling fixture attached to the upper right hook are described. 90 on the next support
゜ Cross and fix to form a truss structure.

The distance between the strut 31 and the panel that is arranged vertically apart from the strut in front of the strut 31 is after the diagonally left (or right) upward connecting member of the connecting fixture at the lower stage to be fixed on the same strut. The end and the rear end of the diagonally left (or right) downward connecting member of the upper stage connecting fixture are set to intersect at a predetermined angle, for example, 90 ° at the column.

As shown in FIG. 5, the first row of panels in row A is erected on the foundation, and the diagonally left-upward connecting members 16 of the connecting fixtures 11'L and 11L attached to the lower left and upper hooks thereof.
L, an obliquely left-downward connecting member 14L, and a connecting fixture 11'R attached to a hook at the lower right and upper right of the panel.
The rear ends of the diagonally upper right connecting member 16R and the diagonally lower right connecting member 11R of 11R are respectively fixed to two pairs of columns located behind the left and right ends of the panel. Next, the left and right hooks under the panel of the second row B are fitted to the upper part of the fixing member of the connecting fixture attached to the upper left and right hooks of the row A, and the panel is erected at the break joint. The lower portions of the fixing members of the connecting fixture are fitted to the left and right hooks on the panel. FIG. 5A shows the connecting fixtures PQRS and P'Q'R'S 'for easy understanding. The obliquely left-upward connecting member 13L of the connecting fixture Q and the obliquely left-downward connecting member 14L of the connecting fixture S, and the obliquely right-upward connecting member 13R of the connecting fixture P and the obliquely right-downward connecting member 14R of the connecting fixture R are formed. Each rear end is fixed to one support 31-1 located behind the center of the width of the panel. This one column is one of two columns 31-1, 31-2 that fix the rear ends of the left and right connecting members of one panel in row A.
1-1, and the other support 31-2 has the connecting fixtures P'Q'R'S 'fitted to the upper and lower left and right hooks of the panel adjacent to the one panel in the row B facing obliquely upward and leftward. The rear ends of the connecting member and the obliquely left-downward connecting member, and the obliquely rightward and downwardly obliquely downward connecting member are fixed.
Diagonally left (or right) upward connecting member 13 of lower connecting fixtures Q, P whose rear ends are fixed to the same support, for example, 31-1
The rear ends of the L and 13R and the diagonally left (or right) downward connecting members 14L and 14R of the upper connecting fixtures S and R are predetermined at the support 31-1 as described above. At an angle of, and fixed to the column with a truss structure.

On the panel of the second row B in the above manner, the third fixing step is performed at the break joint by using the upper part of the vertical fixing member of the connecting fixture fitted to the hook on the panel. The panel in row A is set up, the rear end of the connecting member of each connecting fixture is fixed to a column, and the panel in row B in the fourth row is set up in the same manner.

After the panels are erected on the foundation in about three or four steps, a filler 51 is filled between the erected panels and the shaved slopes on the back, and the filler is made of concrete or mortar. In the case of hardening, in the case of earth and sand, gravel, etc., after hardening, repeat the process of standing up three or four steps of panels and filling the filler material 51 to repeat the retaining wall of the required height. To construct.

As can be seen in FIG. 3, each time the filler 51 is filled, the column 3 in the truss structure is subjected to the side pressure P of the filler applied to the upper end of the third or fourth row of the uppermost panel.
The pulling force + P 'is applied to each of the connecting members 14L and 14R obliquely downward and rightward with the rear end fixed to 1, and the compressive force is applied to each of the connecting members 13L and 13R obliquely upper left and obliquely upper right. -P 'acts on each other, whereby an upward tensile force + P is applied to the column 31 and a downward compressive force -P is applied to the three or four erected panels. Therefore, a large bending moment does not act on the root of the support on the upper surface of the foundation or on the position of the filler on the support. The second embodiment shown in FIG.
In this case, the number of pillars erected on the foundation is half that of the first embodiment shown in FIG. 2, and the interval between the pillars in the left-right direction is doubled, so that the construction is easy.

In the above description, the V-shaped or U-shaped hook which is opened in the vertical direction as the engaging portion 2 from the upper and lower positions of the back surface inward from both the left and right ends by の of the width is fixed length. Although the example in which the projecting wall form panel is used has been described, the engaging tool of the wall form panel is not limited to a hook. For example, as shown in FIG. 6, an anchor or an anchor bolt may protrude backward as the engaging portion 2 from an upper or lower position on the back surface inward from the left and right ends by １ ／ of the lateral width of the wall form panel.

In this case, the vertical fixing member 12 of the connecting fixing tool 11 for fixing the engaging tool on the lower panel and the lower engaging tool on the upper panel at the break joint is shown in FIG. 7 (A)
For example, as shown in FIG. One side of this angle material is welded through a left (or right) anchor above the lower panel, or a lower part 12d provided with a hole to be fixed with a nut, and a right (or left) lower part below the upper panel. And an upper portion 12u with a hole secured by a nut or a nut. And the connecting members 13 and 14 which are obliquely upward and obliquely downward for constructing the retaining wall of the first embodiment.
Also, the connecting members 13L, 14L, which are diagonally upper left and diagonally lower left, and the diagonally upper right, diagonally lower right connecting members 13R, 14R for retaining wall construction of the second embodiment are welded to other sides of the angle material, What is necessary is just to fix with a bolt and a nut 15.

The fixing members 12 'of the connecting fixture 11' attached to the lower right and left anchors of the lowermost panel and the upper left and right anchors of the uppermost panel are shown in FIG. 7B, for example. As shown in the figure, a metal angle material is used. One side of the angle material includes a hole that is welded through the anchor or secured with a nut. And the connecting member 16 for obliquely upward or obliquely downward for retaining wall construction of the first embodiment,
The connecting member 16L for obliquely left-upward and diagonally left-downward for the construction of the retaining wall of the second embodiment, and the connecting member 16R for obliquely upper-rightward and obliquely rightward downward are respectively provided with bolts and nuts 15 on the other side of the angle material. What is necessary is just to connect and fix.

Thus, the retaining wall of the first embodiment and the retaining wall of the second embodiment can be constructed using the panel of FIG.

[0031]

As is apparent from the above, according to the present invention, since the bending force is not generated on the column 31 and the amount of bending is reduced, a column having a small rigidity, for example, a round steel bar is used instead of an angle steel. The cost of steel can be greatly reduced. Furthermore, the panel is erected about three or four steps using the pillars that stand from the foundation, and the filler is filled between the panel that is erected while filling the filler from below and the cut-off mountain slope. Filling to form the retaining wall makes it easy to widen roads.

[Brief description of the drawings]

FIG. 1 is a perspective view of an example of a wall form panel.

FIG. 2A is a front view of a first embodiment of the retaining wall according to the present invention, and FIG. 2B is a plan view of the same.

FIG. 3 is a side view of the constructed retaining wall.

4 (A) and 4 (B) are perspective views of a connecting fixture for the wall form panel of FIG. 1;

FIG. 5 (A) is an explanatory view showing a front view of a relationship between a panel in a retaining wall construction state, a support, and a connecting fixture according to a second embodiment, and FIG. The top view which shows the connection state with the panel of a line.

FIG. 6 is a perspective view of another example of the wall form panel.

7 (A) and 7 (B) are perspective views of a connecting fixture for the wall form panel of FIG. 6;

FIG. 8 is a side view of a conventional retaining wall.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wall form panel (it is also described simply as a panel) 2 Engagement part 11 Connection fixture 12 Vertical fixing member 13 Diagonally upward connection member 14 Diagonally downward connection member

Claims (1)

[Claims] 1. A base on which columns are erected at predetermined intervals in the left-right direction, engaged with the front of the columns from the upper and lower positions on the back surface shifted inward from both right and left ends by 1/4 of the lateral width. The wall form panels with protruding parts are lined up in a line in the left and right direction,
The same wall form panels are placed on the top of the lower wall form panel in a row in the left and right direction, displaced by a half of the width, and the upper and lower fixing members of the connecting fixture are placed on the engaging portions of the lower wall form panels. Attach the lower side and attach the lower engaging part of the upper wall form panel to the upper side of the fixing member to fix the upper and lower wall form panels at the break joints, thus standing in a line in the horizontal direction The same wall form panels are staggered by a half of the horizontal width on the arranged wall form panels by the fixing member of the connecting fixture, and are repeatedly arranged in a line in the left-right direction. In the retaining wall construction method of fixing the rear end of the connecting member to which the one end is attached to the support, and then constructing the retaining wall by filling a filler on the back side of the plurality of wall form panels arranged vertically. Fix the wall form panels on the upper and lower steps of the connecting fixture A method of constructing a retaining wall, characterized in that an obliquely upward connecting member and an obliquely downward connecting member are provided on a downward fixing member, and the rear ends of the two connecting members are fixed to the support by a truss structure. .