JP4111271B2 - Step unit for stairs, how to build stairs - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a staircase step unit that constitutes one or a plurality of steps of a staircase, and a method for constructing a staircase using a step unit, and particularly to a proposal optimal for renovation.
[0002]
[Prior art]
In the conventional steel frame staircase, the stepped plates for one step are arranged in a staircase shape, and are fixed by sandwiching them with a steel plate girder from both sides of the arranged stepped plates (a steel step described in Patent Document 1). . In this case, in the staircase using the sasara girder, one or half floors were assembled at the factory, and the staircase was fixed to a slab or the like at the construction site.
[0003]
In addition, a wooden staircase has been proposed in which a plurality of steps are stacked on a gantry to form a staircase (Patent Document 2).
[0004]
[Patent Document 1]
JP 2001-207611 A
[Patent Document 2]
Japanese Patent Publication No. 8-16382 [0006]
[Problems to be solved by the invention]
Stairs using sasara girders are generally heavy, requiring heavy machinery and a lot of manpower. Moreover, when replacing a part by renovation etc., all the stairs were removed.
[0007]
Also. The wooden staircase is relatively light, so the above-mentioned stacked staircase has also been proposed, but it cannot be applied to a steel plate staircase.
[0008]
[Means for Solving the Problems]
However, in the present invention, since the staircase is constructed by using one or a plurality of step units and stacked in a staircase shape, the above problem is solved.
[0009]
That is, the invention of the step unit is a step in which one end or a plurality of steps of a staircase having a predetermined width is fixed by sandwiching both ends of a step plate between connecting members, and is stacked up and down to form a staircase, An upper joining means for connecting to another connecting member located above is formed at least on the base end side at the upper edge of the connecting member, and positioned at the lower end at least on the distal end side at the lower edge of the connecting member. Forming a lower joining means for connecting with another connecting member, wherein the upper joining means and the lower joining means are respectively bolt holes, and a plurality of reinforcements are provided between the upper joining means and the lower joining means in the connecting member. A step unit for a staircase, characterized in that the ribs are vertically connected and the reinforcing ribs are steps positioned up and down so as to be aligned vertically.
[0010]
In the above, the connecting member includes a vertical plate portion for fixing the tread plate, an upper flange on the upper edge of the vertical plate portion, and a lower flange on the lower edge, and a bolt hole on the base end side of the upper flange. Is formed as an upper joining means, and a bolt hole is bored on the distal end side of the lower flange to serve as a lower joining means, and a plurality of vertical plate portions are provided between the upper flange and the lower flange. A step unit in which reinforcing ribs are vertically arranged.
[0011]
In addition, the invention of the construction method of stairs is
(1) A method for constructing a stairway between constitutes a footstep unit having a step plate of the stairs for one stage having a predetermined width and upper and lower flanges, standard floor and the upper floor, the footstep unit, vertical A plurality of reinforcing ribs are formed vertically between the flanges.
(2) The first step unit is fixed to the floor frame of the reference floor, and the upper and lower flanges are in contact with each other by placing the second step unit on the first step unit while shifting the position in a staircase pattern. Are connected to each other so that they can be disassembled.
(3) Similarly to (2), the second step unit is shifted in a stepped manner, the third step unit is arranged and fixed to each other, and thereafter, the necessary number of step units are stacked in the same manner.
(4) Instead of the steps (2) and (3), or together with the steps (2) and (3),
The step unit is fixed to the upper floor case, and other step units are stacked in a stepped manner on the lower surface of the step unit fixed to the upper floor, and the abutted upper and lower flanges are connected to each other so as to be disassembled. Repeat the same step unit.
(5) The reinforcing ribs are connected so as to be aligned vertically in the step units adjacent to the top and bottom.
(6) A staircase construction method characterized by constructing a stairway as described above.
[0012]
In addition, other stairs construction methods
(1) Consists of a step unit having a stepped stair plate and a top and bottom flange with a predetermined width, and a step unit group formed by shifting one or more step units in a staircase pattern and connecting them. A method of constructing a staircase between a reference floor and an upper floor, wherein the step unit has a plurality of reinforcing ribs vertically formed between upper and lower flanges.
(2) The first step unit group is fixed to the floor frame of the reference floor, and the second step unit group is placed on the first step unit group by shifting the position in a staircase pattern on the first step unit group. The upper and lower flanges are connected to each other so that they can be disassembled.
(3) As in (2), the second step unit group is shifted in a stepped manner, the third step unit group is arranged and fixed to each other, and thereafter, the necessary number of step unit groups are stacked in the same manner.
(4) Instead of the steps (2) and (3), or together with the steps (2) and (3),
The step unit group is fixed to the upper floor case, and another step unit group is stacked on the lower surface of the step unit group fixed to the upper floor in a staircase shape, and the abutted upper and lower flanges are connected to each other so as to be disassembled. In the same manner, the step unit groups are overlapped.
(5) The reinforcing ribs are connected so as to be aligned vertically in the step units adjacent to the top and bottom.
(6) A staircase construction method characterized by constructing a stairway as described above.
[0013]
The tip in the above refers to the end of the step on the nose side, and the base end refers to the back side opposite to the nose.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The steel plate is bent to form a U-shaped connecting member 1 in which the upper flange 5 and the lower flange 7 are connected to the upper and lower edges of the vertical plate portion 2, respectively, and the distal end side (the nose side) of the lower flanges 7 and 7 ), And through holes 9 and 9 are formed at the same interval on the base end side (opposite side of the nose) of the through holes 10 and 10 and the upper flanges 5 and 5, respectively. In the vertical plate portion 2, a surface on the side where the flanges 5 and 7 are located is a convex side surface 3, and a surface opposite to the convex side surface 3 is a concave side surface 4.
[0015]
Between the upper and lower flanges 5, 7, the reinforcing ribs 12, 12 having protrusions 13 and arranged at the same interval are fixed to the concave side surface 4 of the vertical plate portion 2 by welding. Through holes 14 and 14 for attaching handrails are formed in the protruding portion 13 of the reinforcing rib 12. The reinforcing rib 12A located at the center is located at the center of the through hole 9A at the most distal end of the upper flange 5 and the through hole 10A at the most proximal side of the lower flange 7.
[0016]
The steel plate is bent, and the tread 16 is formed by bending the distal end side and the proximal end side to form the ribs 17 and 18 (FIGS. 2 and 1A). The step board 16 is sandwiched between the connecting members 1 and 1 disposed so that the convex side surfaces 3 face each other, and both ends 19 and 19 of the step board 16 are welded to the connecting members 1 and 1 to constitute the step unit 20 of the present invention (FIG. 1, FIG. 2, FIG. 9 (a)).
[0017]
[Example 1]
An embodiment of the step unit 20 of the present invention will be described with reference to the drawings.
[0018]
[1] Configuration of the step unit 20 [0019]
(1) A connecting member 1 having a U-shaped cross section in which a steel plate is bent, and an upper flange 5 and a lower flange 7 are continuously provided on the upper edge of the vertical plate portion 2 having a width D ₁ and a height H _1. Constitute. Through holes 10 and 10 are drilled at equal intervals L ₀ on the distal end side (nosing side) of the lower flanges 7 and 7. Through holes 9 and 9 are also drilled at the same interval L ₀ on the base end side (the opposite side of the nose) of the upper flanges 5 and 5. In the vertical plate portion 2, a surface on the side where the flanges 5 and 7 are located is a convex side surface 3, and a surface opposite to the convex side surface 3 is a concave side surface 4.
[0020]
Between the upper and lower flanges 5, 7, the vertical reinforcing ribs 12, 12 are fixed to the concave side surface 4 of the vertical plate portion 2 by three. The upper and lower edges of the reinforcing rib 12 are welded and fixed to the upper and lower flanges 5 and 7, and the base ends are fixed to the concave side surface 4 of the vertical plate portion 2 by welding. Further, the tip of the reinforcing rib 12 forms a protruding portion 13 that protrudes outward in the lateral direction by a length L ₃ from the tips of the upper and lower flanges 5, 7. Through holes 14 and 14 for attaching handrails are formed in the protruding portion 13 of the reinforcing rib 12.
[0021]
The reinforcing ribs 12, 12 are arranged at a distance L ₂ , and the reinforcing rib 12 A located in the center is arranged at a distance L _{1 from} the through hole 9 A on the most distal end side of the upper flange 5, and the lower flange 7 the distance between the through hole 10A of the rearmost are also formed in L _1. That is, the reinforcing rib 12 </ b> A located at the center is located at the center of the through hole 9 </ b> A at the most distal end of the upper flange 5 and the through hole 10 </ b> A at the most proximal end side of the lower flange 7.
[0022]
(2) The tread 16 having the required tread length L ₄ and width D ₄ is formed. The edge on the front end side of the tread board 16 is bent downward to form a rib 17, and the edge on the base end side is bent upward to form a rib 18 (FIGS. 2 and 1A).
[0023]
(3) The connecting members 1 and 1 having a U-shaped cross section are disposed so that the convex side surfaces (sides on which the reinforcing ribs are not fixed) 3 face each other, and the tread plate 16 is connected to the vertical plate portions 2 and 2 of the connecting members 1 and 1. The contact positions of the tread plate 16 and the vertical plate portions 2 and 2 are appropriately welded with the both ends 19 and 19 interposed therebetween. The step unit 20 is configured as described above (FIGS. 1, 2, and 9A).
[0024]
[2] Other embodiments
(1) In the above embodiment, the reinforcing ribs 12 are arranged so that the reinforcing ribs 12 and 12 are aligned vertically (vertically) in the upper and lower step units 20 and 20 when the step units 20 and 20 are stacked one above the other. In the case of using an odd number of reinforcing ribs 12, 12, the reinforcing ribs 12 A are arranged at equal intervals, and the reinforcing ribs 12 A located in the center are arranged at equal distances L ₁ from the through holes 9, 10. Unless consideration is given to aligning the reinforcing ribs 12 vertically, the number and arrangement of the reinforcing ribs 12 are arbitrary (not shown).
[0026]
(2) In the embodiment, the end portion 19 of the tread plate 16 is brought into contact with the vertical plate portion 2. However, an opening corresponding to the cross-sectional shape of the tread plate 16 is formed in the vertical plate portion 2 in advance. It is also possible to configure the step unit 20 (not shown) by inserting the end portions 19 and 19 of the step board 16 and welding the necessary portions.
[0027]
(3) Moreover, in the said Example, although the front-end | tip of the reinforcement rib 12 protruded from the upper and lower flanges 5 and 7, the protrusion part 13 was formed, and the through-holes 14 and 14 for handrail attachment were formed in the protrusion part 13, When the handrail (for example, the handrail panel 31, FIG. 7) is not used, or when the handrail 31 is fixed to the upper surface 6 of the upper flange 5, the protrusion 13 and the through holes 14 and 14 of the reinforcing rib 12 are not necessary. (FIG. 9B).
[0028]
(4) Moreover, in the said Example, although the connection member 1 was arrange | positioned with the convex side surface 2 facing, the concave side surface (side in which the reinforcing rib was formed) 3 of the connection member 1 was opposed, and the vertical plate part 2 was made. It is also possible to fix the tread 16 by abutting the edges 19 and 19 of the tread (FIG. 9C). In this case, two reinforcing ribs 12 and 12 are arranged on the distal end side and the proximal end side so as not to be buffered with the tread plate 16. Further, the ribs 17 and the like of the tread plate 16 are appropriately cut out so that the reinforcing ribs 12 and 12 and the tread plate 16 are not buffered (FIGS. 9C and 9D).
[0029]
Also in this case, when the handrail 31 is used, it is fixed to the upper surface 6 of the upper flange 5 (FIG. 9C), or the convex side surfaces (outer surface) 3, 3 of the connecting members 1, 1. Then, the mounting rib 22 having the through hole 23 is protruded (FIG. 9D).
[0030]
(5) Further, in the above embodiment, the distance _{L 2} of the reinforcing rib 12, when overlapping the step units 20, 20 up and down, as the reinforcing ribs 12, 12 are aligned in the vertical (longitudinal direction), the step unit distance of shifting the 20, 20, i.e., has been set to correspond to a valid tread length is arbitrary (not shown).
[0031]
(6) In the above embodiment, the through holes 9 and 10 are formed on the proximal end side of the upper flange 5 and the distal end side of the lower flange 10, respectively. The through-hole 9 can be drilled at the same plane position as 10 and 10, and the through-hole 10 can also be drilled at the same plane position as the through-hole 9 of the upper flange 7 (not shown). . That is, the upper and lower flanges 5,7, the same planar position, the six through holes at intervals L _0, is to be formed.
[0032]
In this case, the through hole 9 (not used for connecting the step unit) 9 on the front end side of the upper flange 5 can be used as a bolt hole for attaching the handrail, and the uppermost step unit 20 is fixed to the upper floor slab. Available for use. Further, a through hole 10 (not used for connecting the step unit) 10 on the base end side of the lower flange 7 can be used as a bolt hole for mounting a decorative panel on the bottom side of the staircase, and in the step unit 20 used at the bottom, It can be used as a bolt hole for fixing to the slab on the reference floor (not shown).
[0033]
[Example 2]
Next, the staircase structure 30 using the step unit 20 of the above embodiment will be described.
[0034]
[1] Construction of staircase structure 30
(1) The through holes 9 and 9 of the lower flange 7 of the first step unit 20A are passed through the screws (bolt shafts) 26 and 26 protruding from the upper surface of the reference floor slab 25, and nuts are tightened on the screws to form the first step The unit 20A is fixed to the reference floor slab 25. In the figure, reference numeral 48 denotes abandoned concrete for keeping the stair unit 20A at a predetermined height in consideration of the finished surface of the floor.
[0036]
(2) The lower flanges 7 and 7 of the second step unit 20 are placed on the upper flanges 5 and 5 of the first step unit 20A, and the second step unit 20 is shifted stepwise toward the base end side to The through holes 9 and 9 of the upper flange 5 of the step unit 20A and the through holes 10 and 10 of the lower flanges 7 and 7 of the second step unit are communicated. Bolts are inserted into the through holes 9 and 10 communicated with each other, and nuts are screwed and fastened to connect and fix the first step unit 20A and the second step unit 20.
[0037]
In this state, the upper and lower step units 20A, 20 are arranged so that the reinforcing ribs 12, 12 are aligned vertically (in the vertical direction). Therefore, even when a relatively thin steel plate is used, the strength of the connected stair unit (the whole staircase) can be increased. In addition, a predetermined tread length can be secured.
[0038]
(3) Hereinafter, similarly, the step units 20 and 20 are sequentially connected in a staggered manner while being stacked.
[0039]
(4) In the uppermost step unit 20B, through holes 24, 24 are previously drilled in the upper flange 5, and the through holes 29, 29, the through holes 24 of the angle member 28 fixed to the upper floor slab 27, A bolt is inserted into 24 and fixed with a nut (FIGS. 6A and 6B). The staircase structure 30 is configured as described above (FIGS. 3 to 5).
[0040]
In the figure, reference numeral 49 denotes an intermediate landing, which is fixed to the columns 40 and 40 that are erected and fixed to the reference floor slab 25 (FIGS. 3 to 5).
[0041]
(5) In the staircase structure 30 constructed by using the staircase unit 20 in this way, since one staircase unit 20 is formed to be light, tightening with bolts and nuts without using heavy machinery or the like for assembly. The staircase structure 30 can be formed by a simple operation only by operation. Further, in the staircase structure 30 formed in this way, even when one part of the step unit 20 is damaged, the bolts and nuts can be loosened and only the damaged step unit 20 can be removed and replaced. Therefore, at the time of renovation, it is possible to easily remove the stair units 20, 20 and reassemble the stair units 20 after repairing them by painting or replacing parts.
[0042]
(6) Here, the step units 20 are stacked and connected one by one at the construction site, but about two to three steps at the factory can be connected in advance at the factory and transported to the construction site. . In this case, it is desirable that the number of connections be such that it can be lifted without using heavy machinery on site.
[0043]
[2] Staircase structure 30 using handrail panel 31
[0044]
(1) In the said Example, the handrail panels 31 and 31 can be attached to the step units 20 and 20, and the staircase structure 30 can also be comprised (FIG. 7, 8).
[0045]
(2) The handrail panel 31 is formed by combining vertical members 33 and 35 and cross members 37 and 38 made of angle steel (angle members) to form a panel base 32 having a height L ₁₁ and a width L ₁₂ . The vertical member 33 is extended downward to form a leg portion 42 (FIG. 7). In the opening 41 of the panel base 32, vertical and horizontal bars are fixed in a lattice shape (FIG. 7B). In addition, through holes 39 are formed in the flange 34 of the vertical member 33 on one side to join the adjacent handrail panel (upper stage) 31. Further, three through holes 39 are formed at equal intervals in the flange 36 of the vertical member 35 on the other side to join the adjacent handrail panel (lower stage) 20 (FIG. 7C). ).
[0046]
The leg portion 42 is provided with two sets of two through holes 44, 44 communicating with the through holes 14, 14 of the reinforcing rib 12 of the step unit 20, and a total of four through holes. Two pairs of through holes 40, 40 communicating with the through holes 14, 14 of the reinforcing rib 12 are also drilled in the lower end portion of 33 (FIG. 7A). The pair of through holes 40 and 40 and the through holes 44 and 44 are formed in accordance with the distance L ₅ (FIG. 2) between the through holes 14 and 14 of the reinforcing rib 12.
[0047]
(3) The handrail panel 31 (reference handrail panel 31C) formed in this way has a lateral member 38 on the lower side of the panel base 32 positioned near the upper flange 5 of the reference step unit 20C, and is a vertical member. 33 and the leg part 42 are arrange | positioned at the base end side, and the vertical member 35 is each arrange | positioned at the front end side (FIG. 8 (a)). The adjacent handrail panels 31 and 31 are arranged with the flange 34 of the longitudinal member 33 and the flange 36 of the longitudinal member 35 in contact with each other.
[0048]
Further, the through holes 44 and 44 of the leg portion 42 of the handrail panel 31 are connected to the through holes 14 and 14 of the central reinforcing rib 12A of the stair unit 20A serving as a reference, and the base end side of the stair unit 20 positioned below. The reinforcing rib 12 communicates with the through holes 14 and 14. A nut is screwed into and tightened through the communicating through holes 14 and 44 through bolts, and the handrail panel 31C is attached to the step units 20A and 20.
[0049]
Further, in the adjacent handrail panels 31C and 31, the through holes 39 and 39 of the vertical members 33 and 35 are communicated with the flanges 34 and 36 that are in contact with each other, so that a nut is screwed through a bolt through the communicated through holes 39 and 39. The handrail panels 31C and 31 adjacent to each other are fixed together.
[0050]
As described above, the staircase structure 30 to which the handrail panel 31 is attached is configured (FIG. 8).
[0051]
(4) Since the handrail panel 31 connects the handrail panels 31 and 31 adjacent to each other with bolts and nuts, and the handrail panel 31 and the step units 20 and 20, parts can be replaced even if part of them is damaged. Easy. Moreover, when renovating, it can be easily removed together with the step units 20 and 20.
[0052]
【The invention's effect】
Since this stair unit is equipped with upper and lower joining means, it is possible to mount one stair unit so that it stacks up and down, so use heavy machinery and special jigs and tools at the construction site There is an effect that the stairs can be assembled. Even if one stair unit is damaged, only the damaged stair unit can be replaced. Therefore, at the time of future reform, the disassembled stair unit can be reassembled by replacing parts or painting.
[0053]
In addition, when joining means is composed of upper and lower flanges, bolts are inserted into the through holes that are connected and tightened with nuts, the assembling work can be simplified and the disassembling and assembling of the stair unit can be performed efficiently even if it is not a skilled worker. Therefore, the construction period can be shortened.
[0054]
In addition, when the reinforcing ribs are provided vertically, the connecting member can be reinforced to reduce the thickness of the connecting member, so that the step unit can be reduced in weight and the working efficiency can be further improved. Furthermore, when mounting the reinforcing ribs at positions symmetrical with respect to the base end direction and the distal end direction with respect to the bolt holes, the reinforcing ribs are arranged vertically in the stacked step unit, so the completed staircase structure There is an effect that can be further reinforced.
[Brief description of the drawings]
1A is a front view, FIG. 1B is a plan view, FIG. 1C is a side view, and FIG. 1D is a bottom view.
FIG. 2 is a perspective view of the same.
FIG. 3 is a plan view in which a part on the reference floor side is broken in a staircase structure using the step unit of the present invention.
FIG. 4 is a plan view in which a part of the upper floor side is also broken.
FIG. 5 is a side view of the same.
6A is a partially enlarged side view of the upper floor side of the staircase structure, and FIG. 6B is a partially enlarged front view in which reinforcing ribs are omitted.
7A is a left side view, FIG. 7B is a front view, FIG. 7C is a right side view, and FIG. 7D is a bottom view.
FIGS. 8A and 8B are examples of a staircase structure using a handrail panel, in which FIG. 8A is a side view and FIG. 8B is a cross-sectional view taken along line AA in FIG.
FIGS. 9A to 9D are a side view and a front view, respectively, of an embodiment of the step unit of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Connecting member 2 Vertical plate part 3 Convex side surface 4 Concave side surface 5 Upper flange 6 Upper flange upper surface 7 Lower flange 9 Through hole of upper flange (bolt hole)
10 Lower flange through hole (bolt hole)
12, 12A Reinforcement rib 13 Reinforcement rib protrusion 14 Reinforcement rib through hole 16 Tread plate 19 Tread plate both ends 20, 20A, 20B, 20C Step unit 22 Mounting rib 23 Mounting rib through hole 24 Upper flange through hole 25 Reference Floor slab 27 Upper floor slab 29 Upper flange through hole 30 Stair structure 31, 31C Handrail panel 32 Panel base 33, 35 Vertical member 37, 38 Cross member 39 Vertical member through hole 40 Vertical member through hole 41 Opening of panel base 42 Leg 44 Leg through-hole 48 Discard concrete 49 Intermediate landing 50 Intermediate landing post

Claims (4)

It is a step that is fixed by sandwiching and fixing both ends of a step plate for one step or a plurality of steps having a predetermined width, and is stacked up and down to form a step.
On the upper edge of the connecting member, at least on the base end side, an upper joining means for connecting with another connecting member located above is formed,
A lower joining means for connecting to another connecting member located below is formed on the lower edge of the connecting member at least on the tip side,
The upper joining means and the lower joining means are respectively bolt holes,
A plurality of reinforcing ribs are vertically connected between the upper joining means and the lower joining means by the connecting member, and the reinforcing ribs are steps positioned up and down and are formed so as to be aligned vertically. Step unit. The connecting member includes a vertical plate portion for fixing the tread plate, an upper flange on the upper edge of the vertical plate portion, a lower flange on the lower edge, and a bolt hole formed on the base end side of the upper flange. , As an upper joining means, by drilling a bolt hole on the tip side of the lower flange, as a lower joining means,
The step unit according to claim 1, wherein a plurality of reinforcing ribs are vertically connected to the vertical plate portion between the upper flange and the lower flange. (1) A method of constructing a step unit having a stair step plate for a single step having a predetermined width and an upper and lower flange, and constructing a stair between a reference floor and an upper floor. A plurality of reinforcing ribs are formed vertically between the flanges.
(2) The first step unit is fixed to the floor frame of the reference floor, the second step unit is placed on the first step unit in a staircase shape, and the upper and lower flanges are in contact with each other. Are connected to each other so that they can be disassembled.
(3) Similarly to (2), the second step unit is shifted in a stepped manner, the third step unit is arranged and fixed to each other, and thereafter, the necessary number of step units are stacked in the same manner.
(4) Instead of the steps (2) and (3), or together with the steps (2) and (3),
The step unit is fixed to the upper floor case, and other step units are stacked in a stepped manner on the lower surface of the step unit fixed to the upper floor, and the abutted upper and lower flanges are connected to each other so as to be disassembled. Repeat the same step unit.
(5) The reinforcing ribs are connected so as to be aligned vertically in the step units adjacent in the vertical direction.
(6) A method for constructing stairs characterized by constructing stairs as described above. (1) Consists of a step unit having a stepped stair plate and a top and bottom flange with a predetermined width, and a step unit group formed by shifting one or more step units in a staircase pattern and connecting them. A method of constructing a staircase between a reference floor and an upper floor, wherein the step unit has a plurality of reinforcing ribs vertically formed between upper and lower flanges.
(2) The first step unit group is fixed to the floor frame of the reference floor, and the second step unit group is placed on the first step unit group by shifting the position in a staircase pattern on the first step unit group. The upper and lower flanges are connected to each other so that they can be disassembled.
(3) As in (2), the second step unit group is shifted in a stepped manner, the third step unit group is arranged and fixed to each other, and thereafter, the necessary number of step unit groups are stacked in the same manner.
(4) Instead of the steps (2) and (3), or together with the steps (2) and (3),
The step unit group is fixed to the upper floor case, and another step unit group is stacked on the lower surface of the step unit group fixed to the upper floor in a staircase shape, and the abutted upper and lower flanges are connected to each other in a dismountable manner. In the same manner, the step unit groups are overlapped.
(5) The reinforcing ribs are connected so as to be aligned vertically in the step units adjacent in the vertical direction.
(6) A method for constructing stairs characterized by constructing stairs as described above.

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