JP2017095989A - Steel staircase and installation method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steel staircase capable of saving trouble and cost required to install the steel staircase.SOLUTION: A steel staircase is installed between a skeleton on an upper floor and that on a lower floor of a structure. The steel staircase comprises: a pair of girder parts; multiple foot boards supported between the pair of girder parts; an upper fixing part, which fixes the pair of girder parts to the skeleton on the upper floor; and a lower fixing part, which fixes the pair of girder parts to the skeleton on the lower floor and is located between the pair of girder parts and has an open hole into which an anchor bolt projecting from a floor face of the lower floor is inserted.SELECTED DRAWING: Figure 1

Description

  The technology disclosed in this specification relates to a steel step.

  There is known a steel staircase that is attached between an upper-level frame and a lower-level frame of a structure such as a building or a civil engineering structure (see, for example, Patent Document 1). Generally, a steel staircase is provided with a lower fixing portion in which a through hole into which an anchor bolt fixed to a lower-level casing is inserted is formed. For example, the lower fixing part is provided inside and outside the girder part of the steel staircase. When installing a steel staircase, provide a recess in the lower floor and install the lower fixing part in the recess so that the anchor bolt protruding from the bottom of the recess is inserted into the through hole formed in the lower fixing part. Then, the lower fixing portion is fixed with a nut, and concrete is placed in the concave portion. As a result, the floor surface becomes flat, and the lower fixing portion provided outside the girder portion of the steel frame staircase is covered with concrete, so that the fit is improved.

JP 2002-294959 A

  As in the above prior art, when a recess is provided in the floor on the lower floor, a step is generated on the floor on the lower floor. Therefore, it is necessary to perform step bar arrangement for adding bar arrangements such as step beams. Furthermore, in order to fill the concave portion and flatten the floor surface, it is necessary to additionally perform floor reinforcement of the concave portion, concrete placement and the like. Therefore, there has been a problem that labor and cost required for attaching the steel stairs increase.

  The present specification discloses a technique capable of solving at least a part of the problems described above.

(1) A steel staircase disclosed in the present specification is a steel staircase attached between a structure on an upper floor and a structure on a lower floor of a structure, and includes a pair of girders and the pair of girders. A plurality of treads supported in between, an upper fixing part for fixing the pair of girders to the upper floor case, and a lower fixing part for fixing the pair of girders to the lower case case, A lower fixing portion that is located between the pair of girders and has a through hole into which an anchor bolt protruding from the floor surface of the lower floor is inserted. According to this steel frame staircase, the lower fixing part is fixed to the anchor bolt protruding from the floor of the lower floor, so the lower fixing part is fixed to the anchor bolt on the floor of the lower floor, Since the fixing part is arranged between the pair of beam parts, the lower fixing part fixed to the anchor bolt does not protrude from the floor surface of the lower floor outside the pair of beam parts, It can improve the fit. Therefore, it is not necessary to provide a recess in the lower housing to cover the lower fixing portion, and it is possible to reduce labor and cost required for mounting the steel steps.

(2) In the steel frame staircase, the lower fixing portion may be arranged below the tread. According to the present steel frame staircase, the lower fixing part can be covered with the tread board, and the fit around the lower part of the steel frame staircase can be improved.

(3) In the steel step, the tread plate located above the lower fixing portion is provided with an opening penetrating in the vertical direction, and the steel step further has a lid portion for opening and closing the opening. It is good also as a structure. According to this steel frame staircase, an operator who performs the work of installing and fixing the lower fixing portion to the lower-level frame, installs it while visually observing the anchor bolt through the opening from above the tread, and nuts through the opening. Fixing work such as tightening can be performed, and the labor required to attach the steel stairs can be suppressed. In addition, according to the present steel frame staircase, since it has a lid part that opens and closes the opening, when using the steel staircase, the user who uses the steel staircase can safely move the steel staircase by closing the opening with the lid part. Can be used.

(4) In the steel frame staircase, further comprising a plurality of kick plates supported between the pair of girders, and the lower fixing portion is a lowermost tread arranged at the lowermost of the plurality of treads It is good also as a structure arrange | positioned rather than the lowest kick board arrange | positioned between the floor surface of the said lower floor and the said steel-steel staircase. According to the present steel staircase, the lower fixing portion can be covered using the kick plate, and the fit around the lower portion of the steel staircase can be further improved.

(5) In the steel frame staircase, the lower fixing portion is fixed to a surface on the other spar portion side of one spar portion of the pair of spar portions, and is disposed substantially parallel to the tread plate and the penetrating through. A first lower fixing part having a first flat part in which a hole is formed, and the one of the pair of girder parts, the other girder part being fixed to the surface of the one girder part side, and substantially parallel to the tread plate It is good also as a structure including the 2nd lower fixing | fixed part which has a 2nd plane part in which the said through-hole was formed while arrange | positioning. According to this steel frame staircase, one girder part of a pair of girder parts can be fixed to the lower floor frame using the first lower fixing part, and a pair of girder parts using the second lower fixing part. The other girder can be fixed to the lower frame.

(6) In the steel frame staircase, the lower fixing portion may be disposed below a lowermost tread that is disposed at a lowermost position among the plurality of treads. According to this steel frame staircase, the length of the anchor bolt that needs to be exposed from the floor of the lower floor is shortened as compared with the case where the lower fixing portion is disposed at the same height as or higher than the first tread. It is possible to reduce the labor and cost required for mounting the steel stairs.

(7) The technology disclosed in the present specification can be realized in various forms, for example, in the form of a method for manufacturing a steel staircase, a method for attaching a steel staircase, or the like. is there. The steel staircase mounting method disclosed in the present specification is a steel staircase mounting method in which a steel staircase is mounted between a structure on an upper floor and a floor on a lower floor of a structure, from the floor surface of the lower floor. Installation in which the steel staircase is installed on the lower floor housing so that the protruding anchor bolt is inserted into a through hole formed in a lower fixing portion located between a pair of girder portions of the steel staircase And a fixing step of fixing the lower fixing portion to the anchor bolt.

Explanatory drawing which shows roughly the structure of the building 1 to which the steel frame staircase 10 was attached. Explanatory drawing which shows roughly the connection structure of the steel stairs 10 and the beam 60 Top view schematically showing the connection structure between the steel staircase 10 and the floor 50 Sectional drawing which shows roughly the connection structure of the steel stairs 10 and the floor 50 Front view of steel stairs 10 Rear view of steel stairs 10 Top view of steel stairs 10 Bottom view of steel stairs 10 Right side view of steel stairs 10 Left side view of steel stairs 10

A. Embodiment:
A-1. Structure of the steel stairs 10:
FIG. 1 is an explanatory diagram schematically showing a part of the structure of a building 1 to which a steel staircase 10 according to this embodiment is attached. In FIG. 1, illustration of a part of the finish of the building 1 is omitted. The building 1 is a steel-framed two-story building, and a steel staircase 10 is attached between a beam 60 on the second floor of the building 1 and a floor 50 on the first floor of the building 1. The beam 60 is an example of an upper-level frame, and the floor 50 is an example of a lower-level frame. FIG. 1 shows XYZ axes orthogonal to each other for specifying the direction. In this specification, for convenience, the X-axis positive direction is referred to as the right direction, the X-axis negative direction is referred to as the left direction, the Y-axis positive direction is referred to as the front direction, the Y-axis negative direction is referred to as the rear direction, and Z The positive axis direction is referred to as the upward direction, and the negative Z axis direction is referred to as the downward direction. The same applies to FIG.

  As shown in FIG. 1, the steel staircase 10 includes a pair of beam portions 30 and a step plate portion 20. The pair of girders 30 includes a first girder 30 </ b> A disposed on the right side of the step plate 20 and a second gird 30 </ b> B disposed on the left of the step plate 20. The first girder 30A and the second girder 30B are made of steel plates. The first girder part 30A and the second girder part 30B include a girder center part 36 that is disposed obliquely from the rear lower side toward the front upper side, and a girder part that extends in the front direction from the upper end of the girder central part 36. The upper part 32 and the lower part 38 of the girder part extending rearward from the lower end of the central part 36 of the girder part. The lower end surface of the lower part of the girder part 38 is in contact with the floor surface FL of the floor 50.

  Each girder upper part 32 functions as an upper fixing part that fixes the corresponding girder part 30 to the beam 60. FIG. 2 is an explanatory view schematically showing a connection structure between the steel staircase 10 and the beam 60. As shown in FIG. 2, two through holes 34 into which two bolts 66 can be inserted are formed in the upper portion 32 of the beam portion 30. A mounting plate 62 is fixed to the beam 60 by welding or the like, and two long holes 64 into which two bolts 66 can be inserted are formed in the mounting plate 62. In the steel frame staircase 10 of the present embodiment, when the girder upper portion 32 is fixed to the beam 60, bolts 66 are inserted into the long holes 64 and the through holes 34, and are fixed by nut tightening or the like. Thereby, the girder upper part 32 and the beam 60 are fixed to be movable in the Y-axis direction.

  3 is a top view schematically showing a connection structure between the steel staircase 10 and the floor 50, and FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. As shown in FIGS. 3 and 4, each girder lower portion 38 is provided with a lower fixing portion 40 that fixes the corresponding girder portion 30 to the floor 50. The lower fixing part 40 includes a first lower fixing part 40A and a second lower fixing part 40B. 40 A of 1st lower fixing | fixed parts are joined to the surface of the 2nd spar part 30B side (left side) of the 1st spar part 30A by welding so that it may become substantially parallel to the lowermost tread 21X mentioned later. Further, the second lower fixing portion 40B is joined to the surface of the second girder portion 30B on the first girder portion 30A side (right side) by welding so as to be substantially parallel to the lowermost tread plate 21X. That is, the lower fixing portions 40A and 40B are arranged in the left-right direction on the second digit portion 30B side from the first digit portion 30A and on the first digit portion 30A side from the second digit portion 30B, that is, the pair of digit portions 30. Only on the inner side of the first digit portion 30A on the opposite side of the second digit portion 30B and on the opposite side of the second digit portion 30B from the first digit portion 30A, that is, a pair of It is not arranged outside the girder 30. The first lower fixing portion 40A is an example of a first plane portion, and the second lower fixing portion 40B is an example of a second plane portion.

  Two through holes 42 are formed in the first lower fixing portion 40A, and two through holes 42 are formed in the second lower fixing portion 40B. An anchor bolt 52 is embedded in the floor 50 on which the steel staircase 10 is installed, and the tip of the anchor bolt 52 protrudes above the floor surface FL. In the steel staircase 10 of the present embodiment, when the first lower fixing portion 40A and the second lower fixing portion 40B are fixed to the floor 50, two of the four anchor bolts 52 are two of the first lower fixing portion 40A. The remaining two are inserted into the two through holes 42 of the second lower fixing portion 40B. Then, a washer 45 is inserted into the anchor bolt 52 protruding upward from the through hole 42, and screwed into the thread of the anchor bolt 52 from above the first lower fixing portion 40A and the second lower fixing portion 40B. A nut 44 to be engaged with a thread 46 of the anchor bolt 52 from below the first lower fixing portion 40A and the second lower fixing portion 40B, and the first lower fixing portion 40A and the second lower fixing portion 40B. The first lower fixing portion 40A and the second lower fixing portion 40B are fixed to the anchor bolts 52 by tightening them.

  Next, the step plate portion 20 will be described. The step plate portion 20 is made of a steel plate, and is joined between a pair of beam portions 30 by welding as shown in FIG. The step plate portion 20 includes a plurality of tread plates 21 provided substantially horizontally and a plurality of kick plates 22 provided with the upper side inclined rearward with respect to the vertical. The plurality of treads 21 are arranged at equal intervals in an oblique direction. The plurality of kick plates 22 are disposed between the adjacent tread plates 21. It should be noted that one of the plurality of kick plates 22 is disposed between the lowermost step plate 21 </ b> X and the floor 50 that are disposed on the lowermost side of the plurality of step plates 21. Hereinafter, the kick plate 22 disposed between the lowermost tread plate 21X and the floor 50 is referred to as the lowermost kick plate 22X.

  Openings 24 penetrating the lowermost tread 21X in the vertical direction are formed in the longitudinal direction of the lowermost tread 21X, that is, both end portions in the left-right direction. The steel staircase 10 also has a lid portion 28 that opens and closes the opening 24. The opening 24 includes a first opening 24A provided at the right end portion of the lowermost tread plate 21X and a second opening 24B provided at the left end portion of the lowermost tread plate 21X. The lid portion 28 includes a first lid portion 28A that opens and closes the first opening 24A, and a second lid portion 28B that opens and closes the second opening 24B. The first lid portion 28A is attached to the right side edge of the first opening 24A by a first hinge 26A. The second lid portion 28B is attached to the left side edge of the second opening 24B by a second hinge 26B. The top surfaces of the plurality of treads 21 including the lowermost tread 21 </ b> X are covered with a finishing material after the steel staircase 10 is attached to the building 1. Therefore, even if the openings 24A and 24B are formed in the lowermost tread 21X and the openings 24A and 24B are covered with the lid portions 28A and 28B, the appearance of the steel step 10 is not deteriorated.

  Next, the positional relationship between the lower fixing portions 40A and 40B and the step plate portion 20 will be described. As shown in FIG. 3, the lower fixing portions 40 </ b> A and 40 </ b> B are disposed in the forward direction from the lowest kick plate 22 </ b> X, that is, on the ascending side of the steel step 10. Further, as shown in FIGS. 3 and 4, the lower fixing portions 40A and 40B are arranged below the lowermost tread 21X, and specifically, below the openings 24A and 24B provided in the lowermost tread 21X. Has been.

A-2. How to attach the steel stairs 10:
Next, a method for attaching the steel staircase 10 for attaching the steel staircase 10 between the beam 60 and the floor 50 of the building 1 (hereinafter simply referred to as “attachment method”) will be described. In the attachment method of this embodiment, the installation process and the fixing process are performed in this order. Hereinafter, each step will be described.

(Installation process)
In the attachment method of this embodiment, an installation process is first performed. In the installation process, the steel staircase 10 is installed so that the four anchor bolts 52 protruding from the floor surface FL of the floor 50 are inserted into the through holes 42 respectively formed in the lower fixing portions 40A and 40B. . In the installation process, the lower fixing portions 40A and 40B are installed with the lid portions 28A and 28B provided on the lowermost tread 21X of the steel staircase 10 being opened. Thereby, the operator who performs an installation process can install the steel step 10 while visually checking the anchor bolt 52 and the lower fixing portions 40A and 40B from above the tread plate 21 through the openings 24A and 24B.

  Note that the diameter of each through hole 42 is larger than the diameter of the corresponding anchor bolt 52. Therefore, even when an error occurs in the installation position of the anchor bolt 52, the error can be absorbed by the difference between the diameter of each through hole 42 and the diameter of the corresponding anchor bolt 52, and the steel staircase 10 can be installed. it can.

(Fixing process)
Next, a fixing process is performed. In the fixing step, a washer 45 is inserted into the anchor bolt 52 protruding upward from the through hole 42, and the nut 44 that is screwed into the thread of the anchor bolt 52 from above the lower fixing portions 40A, 40B, the lower fixing portion 40A, The lower fixing portions 40A and 40B are fixed to the anchor bolts 52 by tightening nuts 46 that are screwed into the threads of the anchor bolts 52 from below the lower fixing portions 40A and 40B. Thereby, the steel step 10 is fixed to the floor 50. In the fixing step, nuts are tightened on the anchor bolts 52 in a state where the lid portions 28A and 28B provided on the lowermost tread 21X of the steel staircase 10 are opened. Thereby, the operator who performs a fixing process can perform nut tightening from the upper side of the tread 21 via opening 24A, 24B.

A-3. Design description:
5 to 10 show a steel staircase 10 that is an article according to the design. This article is a steel staircase 10 that is attached between the upper and lower casings of a structure. As shown in FIG. 1 and the like, the present article includes a pair of girders 30 and a stepped plate portion 20, and the floor surface of the lower floor is formed by lower fixing portions 40 </ b> A and 40 </ b> B formed between the pair of girders 30. It is fixed to an anchor bolt 52 protruding from As shown in FIG. 3, the lower fixing portions 40 </ b> A and 40 </ b> B are disposed between the lowermost step plate 21 </ b> X disposed at the lowermost of the plurality of step plates 21 included in the stepped plate portion 20 and the floor surface of the lower floor. It is arranged on the ascending side of the steel staircase 10 with respect to the lowermost kick plate 22X, and is arranged below the lowermost tread plate 21X as shown in FIG. The lower fixing portions 40A and 40B are flat plates made of steel plates, and are disposed so as to be substantially parallel to the lowermost tread plate 21X. Two through holes 42 into which two of the four anchor bolts 52 are inserted are respectively formed in the lower fixing portions 40A and 40B. In FIGS. 5 to 10, a part represented by a solid line is a design to be registered as a partial design.

  As described above, in the steel staircase 10 of this embodiment, the lower fixing portions 40A and 40B are fixed to the anchor bolts 52 protruding from the floor surface FL of the floor 50. Therefore, the lower fixing portions 40A and 40B are fixed to the anchor bolt 52 on the floor surface FL. In the steel frame staircase 10 of the present embodiment, the lower fixing portions 40A and 40B are arranged only inside the pair of girders 30, and members including the lower fixing portions 40A and 40B exist outside the pair of girders 30. Therefore, even if the lower fixing portions 40A and 40B are fixed to the anchor bolts 52 on the floor surface FL, it is possible to improve the fit around the lower portion of the steel staircase 10. Therefore, it is not necessary to provide a recess in the floor 50 and cover the lower fixing portions 40A and 40B. For example, when the floor 50 is made of reinforced concrete, in order to provide a recess in the floor 50, in order to generate a step in the floor 50, it is necessary to perform step reinforcement that adds a reinforcement such as a stepped beam. Furthermore, in order to fill the recess and flatten the floor 50, it is necessary to additionally perform floor reinforcement in the recess, concrete placement, and the like. Therefore, the labor and cost required for mounting the steel staircase 10 increase. In the steel frame staircase 10 of this embodiment, since it is not necessary to provide a recessed part, the effort and cost required for attachment of the steel frame staircase 10 can be suppressed.

  The lower fixing portions 40A and 40B are disposed below the lowermost tread plate 21X. Therefore, the lower fixing portions 40A and 40B can be covered using the lowest tread 21X, and the lower periphery of the steel staircase 10 can be improved. Further, since the lower fixing portions 40A and 40B are disposed below the lowermost tread plate 21X, the floor fixing portions 40A and 40B are disposed at the same height as or higher than the lowermost tread plate 21X. The length of the anchor bolt 52 protruding from the surface FL can be shortened, and the labor and cost required for mounting the steel staircase 10 can be suppressed.

  The lowermost tread 21X is provided with openings 24A and 24B penetrating in the vertical direction. Therefore, an operator who performs the work of installing and fixing the lower fixing portions 40A and 40B on the floor 50 installs the anchor bolts 52 while visually observing the anchor bolts 52 from above the treads 21 through the openings 24A and 24B. The fixing work such as nut tightening can be performed via Therefore, compared with the case where the said operator dives under the tread board 21 and performs work, the said worker can suppress the effort which the steel frame staircase 10 requires for attachment.

  The lower fixing portions 40A and 40B are arranged on the ascending side of the steel staircase 10 with respect to the lowermost kick plate 22X. Therefore, lower fixing part 40A, 40B can be covered using the lowest kick board 22X, and the accommodation of the lower periphery of the steel frame staircase 10 can be improved further.

  The lower fixing part 40 includes a first lower fixing part 40A and a second lower fixing part 40B. Therefore, the first girder part 30A can be fixed to the floor 50 using the first lower fixing part 40A, and the second girder part 30B can be fixed to the floor 50 using the second lower fixing part 40B. Further, since the lower fixing portions 40A and 40B are configured by flat plates, the anchor bolts 52 are inserted into the through holes 42 formed in the lower fixing portions 40A and 40B, and tightened with nuts, thereby lowering the anchor bolts 52 to the lower portions. It is easy to fix the fixing portions 40A and 40B.

B. Variations:
The technology disclosed in the present specification is not limited to the above-described embodiment, and can be modified into various forms without departing from the gist thereof. For example, the following modifications are possible.

  In the said embodiment, although the steel structure building was illustrated as a structure, a structure of a reinforced concrete structure may be sufficient as a structure, and structures other than a building may be sufficient as it. Moreover, although the steel stairs attached between the first floor and the second floor of the building were illustrated as the steel stairs, the steel stairs may be attached between the second floor and the third floor of the building. It may be attached to a higher floor.

  In the above embodiment, as a method of fixing the steel staircase to the upper frame, an example in which the upper part 32 of the pair of girders 30 and the mounting plate 62 attached to the beam 60 are fixed by the bolts 66 is shown. However, the upper part 32 and the attachment plate 62 may be fixed by welding. Further, although the steel staircase upper part 32 which is the upper end of the steel frame staircase is illustrated as an example where the beam upper part 32 does not reach the beam 60, the girder upper part 32 extends to the upper part of the beam 60. May be.

  In the said embodiment, although lower fixing | fixed part 40A, 40B is comprised with the flat plate, it is not restricted to this, The cross section orthogonal to the front-back direction may be comprised with the L-shaped plate. In this case, in the lower fixing portions 40A and 40B, a through hole 42 may be formed in one flat plate of the L-shaped plate, and the other flat plate may be joined to the inner surface of the corresponding beam portion 30 by welding.

  In the above embodiment, the lower fixing portions 40A and 40B are arranged below the lowermost tread 21X, but the present invention is not limited to this, and may be arranged below the treads 21 other than the lowermost tread 21X. In this case, the lower fixing portions 40A and 40B may be arranged at the same height as or higher than the lowermost tread plate 21X, and the tread plate provided with the openings 24A and 24B based on the arrangement of the lower fixing portions 40A and 40B. 21 may be changed as appropriate. Further, for example, the lower fixing portions 40A and 40B are provided below the relatively upper tread 21 among the plurality of treads 21, and the operator can easily perform work without the openings 24A and 24B. In some cases, it is not always necessary to provide the openings 24A and 24B.

  In the above-described embodiment, the openings 24A and 24B are arranged below the lower fixing portions 40A and 40B. However, the openings 24A and 24B are not necessarily arranged below the lower fixing portions 40A and 40B. That is, the openings 24A and 24B are not necessarily fixed to the bottom if they are provided in a range in which an operator can extend the arm from above the tread plate 21 through the openings 24A and 24B and perform fixing work such as nut tightening. There is no need to be disposed above the portions 40A and 40B.

  In the said embodiment, although the step board part 20 is supposed to be provided with the some kick board 22, it is not restricted to this, The step board part 20 does not need to be provided with the kick board 22. FIG.

  In the above-described embodiment, the lower fixing portion 40 is configured by the two lower fixing portions 40A and 40B fixed to each of the pair of beam portions 30, but is not limited thereto. For example, the lower fixing portion 40 may be configured by a continuous steel plate supported between the pair of beam portions 30.

1: Building 10: Steel stairs 20: Step board 21: Tread 21X: Bottom tread 22: Kick board 22X: Bottom tick 24: Opening 28: Lid 30: Girder 32: Girder upper 38: Girder Lower part 40: Lower fixing part 42: Through hole 50: Floor 52: Anchor bolt 60: Beam 62: Mounting plate FL: Floor surface

Claims (7)

A steel staircase attached between the upper and lower floors of the structure,
A pair of girders,
A plurality of treads supported between the pair of girders,
An upper fixing portion for fixing the pair of girders to the upper-level frame;
A lower fixing portion for fixing the pair of girders to the lower-level frame, and a through hole into which an anchor bolt protruding from the floor surface of the lower floor is inserted and located between the pair of girders. A steel staircase comprising: a lower fixing portion formed; A steel staircase according to claim 1,
The lower fixing part is a steel staircase disposed below the tread. A steel staircase according to claim 2,
The tread plate located above the lower fixing portion is provided with an opening penetrating in the vertical direction,
The steel staircase further comprises:
A steel staircase having a lid for opening and closing the opening. The steel staircase according to any one of claims 1 to 3, further comprising:
A plurality of kick plates supported between the pair of girders,
The lower fixing portion is disposed on the ascending side of the steel stairs with respect to the bottom kick plate disposed between the lowermost floor plate disposed at the lowermost of the plurality of floor plates and the floor surface of the lower floor. Steel frame staircase. It is a steel step according to any one of claims 1 to 4,
The lower fixing part is
A first lower portion having a first flat surface portion fixed to the surface of the other spar portion of the pair of spar portions and disposed substantially parallel to the tread plate and having the through hole formed therein. A fixed part;
A second plane part fixed to the surface of the one of the pair of girder parts on the side of the one girder part and disposed substantially parallel to the tread plate and having a through hole formed therein. 2 steel steps including a lower fixing part. A steel step according to any one of claims 1 to 5,
The lower fixing portion is a steel step, which is disposed below a lowermost tread disposed among the plurality of treads. A method for attaching a steel staircase to attach a steel staircase between a structure on an upper floor and a structure on a lower floor,
The steel staircase is connected to the lower floor so that the anchor bolt protruding from the floor surface of the lower floor is inserted into a through hole formed in a lower fixing portion located between a pair of girders of the steel staircase. An installation process for installing the housing;
A fixing step of fixing the lower fixing portion to the anchor bolt.

Images