JP2015094197A - Staircase structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a staircase structure capable of suppressing damage even when it is affected by a large load due to an earthquake or the like.SOLUTION: In a staircase structure 100, a support backing part 33 is fixed to an intermediate story floor part 21 through a second fixing structure 36 with less strength against horizontal force than that of a first fixing structure 34. As a stair unit 30 is fixed to either of a skeleton beam 5 and an intermediate story floor part 21, for example, in the case of a small earthquake or the like, the skeleton beam 5, the intermediate story floor part 21, and the stair unit 30 can tremble integrally. Therefore, the damage to an interior decoration due to tremor can be suppressed. When a large earthquake or the like occurs, the fixation is released in the second fixing structure 36 with less strength against horizontal force than that of the first fixing structure 34. Thus, the skeleton beam 5 and the intermediate story floor part 21 tremble integrally with the stair unit 30 through the first fixing structure 34, and the intermediate story floor part 21 trembles independently from them.

Description

  The present invention relates to a staircase structure.

  Conventionally, as a staircase structure provided over one floor and a floor below the floor, for example, those described in Patent Document 1 and Patent Document 2 are known. Such a staircase structure is configured by bridging a staircase unit having a pair of girders and a step supported by the girders between the floors. The stair unit is fixed to a structure such as a beam on the upper floor on one end side, and is fixed to the floor of the lower floor on the other end side.

Japanese Patent Laid-Open No. 3-187461 JP-A-6-26159

  Here, in the above-described staircase structure, the staircase unit is firmly fixed on both the upper floor and the lower floor. According to such a configuration, when the vibration mode or the like is different between the beam on the upper floor and the floor on the lower floor, a large load acts on the stair unit itself, causing deformation and breaking of the fixed part. There was a possibility.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a staircase structure capable of suppressing damage even when a large load acts due to an earthquake or the like. To do.

  A staircase structure according to the present invention is a staircase structure comprising a beam, a floor portion installed below the beam, and a staircase unit provided over the beam and the floor portion, the staircase unit comprising a step portion, A support base part that supports the step part, the support base part is fixed to the beam via the first fixing structure, and the support base part is more resistant to horizontal force than the floor part and the first fixing structure. It fixes via the 2nd fixing structure with low intensity | strength.

  According to the staircase structure of the present invention, the support base portion of the staircase unit is fixed to the beam via the first fixing structure. Further, the supporting base portion is fixed to the floor portion via a second fixing structure having a lower strength against the horizontal force than the first fixing structure. Therefore, since the stair unit is fixed to both the beam and the floor, the beam, the floor, and the stair unit vibrate together when, for example, a small earthquake or wind vibration due to strong winds occurs. be able to. Therefore, it is possible to prevent the interior from being damaged due to the vibration. On the other hand, when a large earthquake occurs, a large load acts on the staircase unit. Accordingly, the fixing is released in the second fixing structure having a lower strength against the horizontal force than the first fixing structure. As a result, the beam vibrates integrally with the stair unit via the first fixed structure, and the floor vibrates independently of them. Therefore, since stress concentration can be avoided, damage to the stair unit, the beam, and the floor can be suppressed.

  In the staircase structure according to the present invention, the support base part is a rising part that extends in the vertical direction and connects the upper end part of the girder part and the seat part, the girder part that receives the step part, the seat part that is installed on the floor part. The first fixing structure may fix the beam and the rising portion, and the second fixing structure may fix the floor portion and the seat portion. Thus, the part fixed by the 1st fixing structure and the part fixed by the 2nd fixing structure among support base parts can be provided in a different position. Therefore, it can suppress that the influence by the fixation cancellation | release in a 2nd fixing structure exerts on a 1st fixing structure.

  In the staircase structure according to the present invention, the support base part includes a girder part, a seat part, and a rising part at both ends in the width direction of the step part, and the first fixing structure is provided at each of the both ends. The beam and the rising portion may be fixed. Thereby, the horizontal rigidity of the portion fixed by the first fixing structure can be ensured.

  In the staircase structure according to the present invention, the beam is made of H-shaped steel, and the first fixing structure is such that the rising portion has a staircase side fixing portion fixed to the rising portion and a beam side fixed to the lower flange of the beam. The beam-side fixing portion may be formed in a plate shape along the lower flange, and may be fastened to the lower flange at least at two locations in the horizontal direction. Thereby, since it can prevent that a beam side fixing | fixed part rotates with respect to a lower flange, the horizontal rigidity of the part fixed by the 1st fixing structure can be ensured.

  In the staircase structure according to the present invention, the floor plate of the floor portion may be an ALC panel, and the second fixing structure may be a screw penetrating the floor plate. Thereby, the intensity | strength with respect to the horizontal force of a 2nd fixing structure can be made low easily.

  In the staircase structure according to the present invention, the beam is a frame beam that supports the general floor portion of the upper floor of the frame, and the floor portion is an intermediate floor portion that constitutes an intermediate floor between the upper floor and the lower floor. Yes, the intermediate floor is supported by an intermediate floor support structure that is connected to the frame and supports the intermediate floor, and the stepped portion of the stair unit has a difference in height between the general floor and the intermediate floor. Depending on the case, it may be formed in 1 to 5 stages. The staircase unit is spanned between the frame beam and the intermediate floor, but the frame beam and the intermediate floor have different vibration periods during a large earthquake. Moreover, the stair unit is small in height and has high rigidity. Therefore, if the stair unit is fixed to the frame beam and the intermediate floor with strength against high horizontal force, the damage may increase. However, the damage can be suppressed by employing the staircase structure of the present invention.

  According to the present invention, damage can be suppressed even when a large load is applied due to an earthquake or the like.

It is a sectional side view which shows the outline of the building which concerns on embodiment of this invention. It is a plane sectional view showing the outline of the building concerning this embodiment. It is sectional drawing along the III-III line of FIG. It is sectional drawing along the IV-IV line of FIG. It is the figure seen from the direction shown by the arrow V of FIG. It is sectional drawing along the VI-VI line of FIG.

  Hereinafter, embodiments of a staircase structure according to the present invention will be described with reference to the drawings. As shown in FIG. 1 and FIG. 2, the building 1 to which the staircase structure 100 according to the present embodiment is applied is a two-storey (two-layer structure) industrialized house having a steel beam-winning frame, The frame is constituted by a combination of structural members that have been standardized (standardized) in advance. As structural members, in addition to pillars and beams constituting the frame, floor boards and intermediate beams are also included. Each structural member is manufactured at a factory and assembled at a construction site.

  Moreover, the building 1 has a 305 mm planar module (M), and columns and beams (including foundation beams) are arranged on a grid that is defined by an integral multiple of the planar module (M). Specifically, the cores are, for example, a plurality of horizontal cores (first cores) L1, L2 parallel to each other and a plurality of vertical cores (second cores) L3, parallel to each other. L4 is orthogonal to each other to form a lattice, and a column is erected at the intersection of the first core and the second core.

The building 1 includes a first floor F1 and a second floor F2, and an intermediate floor F3 is provided at an intermediate height between the first floor F1 and the second floor F2, and an intermediate floor on the first floor. In the region below the floor F3, a first floor low floor F4 is formed which is one step lower than the first floor F1. Further, the intermediate floor F3 is not located at a position where the height from the first floor F1 to the second floor F2 is equally divided, but is shifted toward the second floor F2 (see FIG. 3). The building 1 includes a lower staircase 2 that connects the first floor and the intermediate floor, and an upper staircase 3 that connects the intermediate floor and the second floor.
[Second floor and non-floor space]

  FIG. 2 is a plan sectional view showing an outline of the building 1. As shown in FIG. 2, the plurality of pillars 4A, 4B, 4C, 4D are respectively erected at four intersections of the first cores L1, L2 and the second cores L3, L4. . More specifically, the column 4A is at the intersection of the first core L1 and the second core L3, and the column 4B is at the intersection of the first core L1 and the second core L4. The column 4C is erected at the intersection of the first core L2 and the second core L4, and the column 4D is erected at the intersection of the first core L2 and the second core L3. . A beam 5 (second floor beam) is installed between the adjacent columns 4A to 4D. The area of the second floor level is divided into a floor area A1 where the floor is laid and a rectangular non-floor area where the floor is not laid (meaning that there is no floor at the second floor level) A2.

In the floor area A1, small beams are appropriately installed between the beams 5 laid in parallel, and a floor board B made of an ALC (lightweight cellular concrete) panel is laid on the beams 5 and on the small beams. Thus, the second floor F2 is formed. On the other hand, the floor board B is not laid in the floorless area A2, and a floor opening S is formed. The floorless area A2 includes a beam 5 constructed on the first core L1 between the pillars 4A and 4B, and a beam 5 constructed on the first core L2 between the pillars 4C and 4D. A beam 5 erected on the second core L3 between the columns 4A and 4D, and a beam 5 erected on the second core L4 between the columns 4B and 4C; It is defined by. That is, the beams 5 that define the floorless area A2 are arranged around the four floors of the floorless area A2.
[Middle floor]

  As shown in FIGS. 2 and 3, the intermediate floor F3 is formed in a partial area in the floorless area A2, and the intermediate floor space S1 and the intermediate floor F3 above the intermediate floor F3 have a high ceiling height. Is a low ceiling space S4 having a low ceiling height. Of the floor opening S (no floor area A2), a part of the area other than the intermediate floor F3 is provided with a stair unit composed of the lower staircase 2 and the upper staircase 3 to form a staircase room S3. The other region is a blow-through portion S2. The intermediate floor F3 is formed of a floor board (floor material) B made of ALC, like the second floor F2. The floor board B extends along the beam 5 that defines the floorless region A2 in a plan view inside the floorless region A2, and is lower than the beam 5 that defines the floorless region A2 and is the foundation beam (first floor beam) 37. Supported by a pair of first intermediate beams 7A and 7B and a pair of second intermediate beams 8A and 8B, and a third intermediate beam 10 installed between the first intermediate beams 7A and 7B. ing. Here, “arranged along the beam 5” includes a case where the beam 5 is arranged away from the beam 5 and extends in the same direction as the extending direction of the beam 5.

  The first intermediate beams 7A and 7B and the second intermediate beams 8A and 8B are joined to each other at their ends to form a rectangular frame-shaped intermediate floor beam frame 9.

  Next, the staircase structure 100 according to the present embodiment will be described. The staircase structure 100 is a staircase that communicates with the intermediate floor F3 and the second floor F2, and is provided at a position different from the upper staircase 3. Specifically, the staircase structure 100 connects the intermediate floor F3 and the second floor F2 at the boundary between the intermediate floor 21 of the intermediate floor F3 and the general floor 22 of the second floor F2. Is. As shown in FIG. 2, in the present embodiment, the general floor portion 22A of the second floor F2 is formed at a position adjacent to the intermediate floor F3 via the second intermediate beam 8A, and the intermediate floor portion A staircase structure 100 is provided at a position that can be moved up and down between 21 and the general floor portion 22A. However, the position where the staircase structure 100 is provided is not particularly limited, and may be provided anywhere as long as the general floor portion 22 and the intermediate floor portion 21 are adjacent to each other. The intermediate floor portion 21 is supported by an intermediate floor support structure 50 that is connected to the housing and supports the intermediate floor. The intermediate floor support structure 50 includes first intermediate beams 7A and 7B and second intermediate beams 8A and 8B that are connected to the housing.

  As shown in FIGS. 4 and 5, the staircase structure 100 includes a frame beam 5, an intermediate floor 21 installed below the frame beam 5, and a staircase provided over the frame beam 5 and the intermediate floor 21. A unit 30. The frame beam 5 is an H-shaped steel configured by connecting an upper flange 41 and a lower flange 42 with a web 43. The stair unit 30 includes a step portion 32 and a support base portion 33 that supports the step portion 32. The support base portion 33 is fixed to the frame beam 5 via the first fixing structure 34 and is connected to the intermediate floor portion 21 via the second fixing structure 36. In the present embodiment, the support base 33 has a pair of support frames 35 on both ends 32 a side in the width direction of the step 32. In the following description, the direction in which the user ascends and descends the stepped portion 32 is the ascending / descending direction D1, the horizontal direction orthogonal to the ascending / descending direction D1 is the width direction D2, and the vertical direction is the up / down direction D3. The ascending / descending direction D1 is inclined with respect to the horizontal direction. In the present embodiment, the inclination angle in the ascending / descending direction D1 is set to 45 ° with respect to the horizontal direction, but the inclination angle is not particularly limited. In the following description, the words “front” and “rear” are used on the basis of the state when the staircase structure 100 is viewed from the intermediate floor portion 21 (the state where the user tries to climb the step portion 32). . FIG. 5 is a view of the staircase structure 100 as seen from the rear side (a view seen from the direction indicated by the arrow V in FIG. 4). However, in FIG. 5, the frame beam 5, the general floor portion 22 </ b> A, and the like are omitted as appropriate for easy understanding of the structure.

  The support frame 35 of the support base portion 33 includes a girder portion 46 that receives the step portion 32, a seat portion 47 that is installed on the intermediate floor portion 21, and an upper end portion and a seat portion that extend in the vertical direction D3 and extends in the vertical direction D3. And a rising portion 48 that connects 47 and 47. The girder 46 is a bar-shaped member having an L-shaped cross section that extends along the ascending / descending direction D1. One end portion 46 a of the beam portion 46 is disposed at a position facing the web 43 of the frame beam 5, and the other end portion 46 b of the beam portion 46 is the upper surface Ba of the floor board B of the intermediate floor portion 21. It arrange | positions in the position spaced apart from the frame beam 5 in the horizontal direction.

  The girder part 46 includes a piece part 46A that extends in the width direction D2 and extends in the up-and-down direction D1, and a piece part 46B that extends downward from the inner edge in the width direction D2 of the piece part 46A and extends in the up-and-down direction D1. . The upper surface of the piece 46A functions as a receiving surface that receives the stepped portion 32. The seat portion 47 is a bar-shaped member having an L-shaped cross section that extends in the horizontal direction along the upper surface Ba on the upper surface Ba of the floor board B of the intermediate floor portion 21. One end portion 47 a of the seat portion 47 is disposed below the end portion 46 a of the beam portion 46, and the other end portion 47 b of the seat portion 47 is disposed at the position of the end portion 46 b of the beam portion 46. The seat 47 extends in the width direction D2 so as to be in contact with the upper surface Ba of the floor board B, and extends in the horizontal direction, and extends horizontally from the inner edge in the width direction D2 of the piece 47A and extends in the horizontal direction. One piece 47B. The rising portion 48 is a bar-shaped member having an L-shaped cross section that extends in the vertical direction D3 at the positions of the end portion 46a of the beam portion 46 and the end portion 47a of the seat portion 47. One end portion 48 a of the rising portion 48 is disposed at the position of the end portion 46 a of the beam portion 46, and the other end portion 48 b of the rising portion 48 is disposed at the position of the end portion 47 a of the seat portion 47. The rising portion 48 includes a piece 48A that extends in the width direction D2 and extends in the vertical direction D3, and a piece 48B that extends from the outer edge in the width direction D2 of the piece 48A to the front side and extends in the vertical direction D3. . One part 48A of the rising part 48 is disposed at a position farther forward than the front end part 42a of the lower flange 42 of the frame beam 5. On the end portion 46a side of the beam portion 46, the piece portion 46B of the beam portion 46 and the piece portion 48B of the rising portion 48 are connected. On the end portion 46b side of the beam portion 46, the piece portion 46B of the beam portion 46 and the piece portion 47B of the seat portion 47 are connected. On the end 47a side of the seat 47, the piece 47B of the seat 47 and the piece 48B of the rising portion 48 are connected.

  The step portion 32 is constituted by a plurality of step plate members 51 provided on the beam portion 46 of the support base portion 33. The step plate member 51 is a member that extends in the width direction D2 with a predetermined cross-sectional shape by bending a plate material. Specifically, the corrugated plate member 51 includes an upper wall portion 51a extending in the horizontal direction, a front wall portion 51b extending downward from the front end portion of the upper wall portion 51a, and a rear end portion of the upper wall portion 51a. A connecting portion 51c extending along the upper surface of the piece portion 46A of the girder portion 46 and a connecting portion 51d extending along the upper surface of the piece portion 46A of the girder portion 46 from the lower end portion of the front wall portion 51b are provided. In the present embodiment, the stepped portion 32 is formed in three steps by arranging the three stepped plate members 51 along the elevating direction D1 with respect to the beam portion 46. However, the step portion 32 may be formed in 1 to 5 steps according to the difference in height between the general floor portion 22 and the intermediate floor portion 21. The upper wall portion 51 a of the uppermost stepped plate member 51 is disposed below the upper surface of the floor plate B of the general floor portion 22 </ b> A placed on the upper surface of the upper flange 41 of the frame beam 5. A finishing material 55 such as a filler or a plate material is provided on the upper surface of the floor board B of the general floor portion 22A, the upper surface of the step board member 51, and the upper surface of the floor board B of the intermediate floor portion 21 thus arranged. . Thus, in this embodiment, a total of four steps are configured. Thus, the design property can be improved by arranging the uppermost step plate member 51 at a position one step lower than the general floor portion 22.

  The first fixing structure 34 fixes the rising portion 48 to the frame beam 5 in the support frames 35 at both ends of the step portion 32. The first fixing structure 34 includes a fixture 61 that fixes the rising portion 48 of each support frame 35 to the frame beam 5. As shown in FIGS. 4, 5, and 6, the fixture 61 includes a staircase side fixing portion 62 that is fixed to the rising portion 48, a beam side fixing portion 63 that is fixed to the lower flange 42 of the frame beam 5, And a connecting portion 64 that connects the stair side fixing portion 62 and the beam side fixing portion 63. The staircase side fixing portion 62 is formed in a plate shape along the outer surface of the piece portion 48 </ b> B of the rising portion 48. The staircase side fixing portion 62 is fastened to the piece portion 48B of the rising portion 48 by a bolt or the like. The connecting portion 64 is formed in a plate shape so as to be bent from the rear end portion of the staircase side fixing portion 62 to the outside in the width direction D2. The beam side fixing portion 63 is bent from the upper end portion of the connecting portion 64 to the rear side, and is formed in a plate shape along the lower surface of the lower flange 42. The beam-side fixing portion 63 is fastened to the lower flange 42 at least at two locations in the horizontal direction (here, the width direction D2). As described above, the first fixing structure 34 uses the fastening structure using the fixing tool 61 to fix the frame beam 5 and the support base portion 33 with high strength against a horizontal force. In the present embodiment, the “horizontal force” is a force that applies a relative displacement in the horizontal direction between the frame beam 5 and the intermediate floor portion 21.

  The second fixing structure 36 fixes the seat portion 47 to the intermediate floor portion 21 with the strength against the horizontal force lower than that of the first fixing structure 34 in the respective support frames 35 at both ends of the step portion 32. The strength with respect to the horizontal force of the first fixed structure 34 is set to a strength with respect to the horizontal force that can maintain the fixation between the frame beam 5 and the stair unit 30 even when a large earthquake or the like occurs. Yes. On the other hand, the strength of the second fixed structure 36 against the horizontal force can be maintained in the case of a small earthquake or strong ground vibration due to wind vibration, etc., and if a large earthquake occurs, the fixation is released. The strength against the horizontal force is set. For example, the second fixing structure 36 includes a screw 68 and a screw receiving portion 69 formed on the piece portion 47 </ b> A of the seat portion 47. The screw receiving portion 69 is configured by a through-hole formed in the piece portion 47A. The screw 68 is inserted into the screw receiving portion 69 and connected to the floor plate B of the intermediate floor portion 21, so that the seat portion 47 is attached to the floor plate B with a strength against a horizontal force lower than that of the first fixing structure 34. Fix it. In FIG. 4, the second fixing structure 36 is provided in the vicinity of the front end 47 b of the seat 47, but the position is not particularly limited and the quantity is not limited. Further, the second fixing structure 36 may have any strength against a horizontal force lower than that of the first fixing structure 34, and a method other than screwing may be employed.

  Next, the operation and effect of the staircase structure 100 of the present invention will be described.

  According to the staircase structure 100 according to the present embodiment, the support base portion 33 of the staircase unit 30 is fixed via the frame beam 5 and the first fixing structure 34. Further, the support base portion 33 is fixed via the intermediate floor portion 21 and the second fixing structure 36 having lower strength against the horizontal force than the first fixing structure 34. Accordingly, since the stair unit 30 is fixed to both the frame beam 5 and the intermediate floor 21, for example, in the case of wind vibration caused by a small earthquake or strong wind, the beam 5 and the intermediate floor are used. The part 21 and the stair unit 30 can vibrate integrally. Therefore, it is possible to prevent the interior from being damaged due to the vibration. On the other hand, when a large earthquake or the like occurs, a large load acts on the stair unit 30. Here, when the frame beam 5 and the stair unit 30 are fixed with high strength against the horizontal force and the intermediate floor portion 21 and the stair unit 30 are fixed with high strength against the horizontal force, the frame beam 5 and the intermediate floor are fixed. Due to the difference in the vibration mode and the like between the floor portion 21, a large load acts on the stair unit 30 itself, and there is a possibility that the deformation and the structure around the fixed portion are destroyed. On the other hand, in the staircase structure 100 according to the present embodiment, the fixing is released in the second fixing structure 36 having a lower strength against the horizontal force than the first fixing structure 34. As a result, the frame beam 5 and the intermediate floor 21 vibrate integrally with the stair unit 30 via the first fixed structure 34, and the intermediate floor 21 vibrates independently of them. Therefore, since concentration of stress can be avoided, damage to the stair unit 30, the frame beam 5, and the intermediate floor portion 21 can be suppressed.

  In the staircase structure 100 according to the present embodiment, the support base portion 33 includes a girder portion 46 that receives the step portion 32, a seat portion 47 that is installed on the intermediate floor portion 21, and a girder portion 46 that extends in the vertical direction. And a rising portion 48 that connects the seat portion 47. Further, the first fixing structure 34 may fix the frame beam 5 and the rising portion 48, and the second fixing structure 36 may fix the intermediate floor portion 21 and the seat portion 47. As described above, the portion fixed by the first fixing structure 34 and the portion fixed by the second fixing structure 36 in the support base portion 33 can be provided at different positions. Therefore, it is possible to suppress the influence due to the release of the fixing in the second fixing structure 36 from being exerted on the first fixing structure 34.

  In the staircase structure according to the present invention, the support base portion 33 includes a beam portion 46, a seat portion 47, and a rising portion 48 at both ends in the width direction of the step portion 32, and the first fixing structure 34 is The frame beam 5 and the rising portion 48 are fixed at both ends. Thereby, the horizontal rigidity of the portion fixed by the first fixing structure 34 can be ensured.

  In the staircase structure 100 according to the present embodiment, the frame beam 5 is made of H-shaped steel, and the first fixing structure 34 includes a staircase side fixing portion 62 fixed to the rising portion 48 and a lower flange 42 of the frame beam 5. And a beam side fixing portion 63 fixed to the beam. The beam side fixing portion 63 is formed in a plate shape along the lower flange 42 and fastened to the lower flange 42 at least at two locations in the horizontal direction. Accordingly, it is possible to prevent the fixing tool 61 from rotating with respect to the lower flange 42, and thus it is possible to ensure the horizontal rigidity of the portion fixed by the first fixing structure 34.

  In the staircase structure 100 according to the present embodiment, the floor board B of the intermediate floor 21 is composed of an ALC panel. For example, the second fixing structure 36 is a screw 68 that penetrates the floor board B. Thereby, the intensity | strength with respect to the horizontal force of the 2nd fixing structure 36 can be made low easily.

  In the staircase structure 100 according to the present embodiment, the beam on which the staircase unit 30 is provided is the frame beam 5 that supports the general floor portion 22 on the upper floor of the housing, and the floor on which the staircase unit 30 is provided is on the upper floor ( This is an intermediate floor portion 21 that constitutes an intermediate floor F3 between the second floor F2) and the lower floor (first floor F1). The intermediate floor 21 is supported by an intermediate floor support structure 50 that is connected to the housing and supports the intermediate floor F3. The step 32 of the stair unit 30 includes the general floor 22 and the intermediate floor 21. It is formed in 1 to 5 steps according to the difference in height. The stair unit 30 is bridged between the frame beam 5 and the intermediate floor portion 21, but the frame beam 5 and the intermediate floor portion 21 have different vibration periods in the event of a large earthquake. Further, the stair unit 30 has a small height and high rigidity. Accordingly, when the stair unit 30 is fixed to the frame beam 5 and the intermediate floor 21 with a high strength against a horizontal force, the damage may be increased. However, the damage can be suppressed by adopting the staircase structure 100 of the present embodiment.

  The present invention is not limited to the above-described embodiment.

  Moreover, in the above-mentioned embodiment, although the beam which provides the staircase unit 30 was the frame beam 5, and the floor part was the intermediate | middle floor part 21, it is not limited to this. For example, the beam on which the stair unit is provided may be an intermediate floor or a second floor beam, and the floor may be the first floor. In this case, the number of steps is higher than that of the above-described stair unit 30. In such a modified example, the first fixing structure having high strength against horizontal force has a floor portion and a stair unit so that humans on the upper floor can escape using the stair unit during an earthquake. It is preferable to fix the beam and the staircase unit rather than fixing them. In the above-described embodiment, each seat 47 is fixed to the floor board B using the second fixing structure. However, the present invention is not limited to this, for example, a connection that connects two seats 47. You may make it provide a seat part and fix this connection seat part to the floor board B using a 2nd fixing structure.

DESCRIPTION OF SYMBOLS 1 ... Building, 5 ... Frame beam (beam), 21 ... Middle floor part (floor part), 30 ... Stair unit, 32 ... Step part, 33 ... Support base part, 34 ... First fixed structure, 36 ... First 2 fixing structure, 35 ... support frame, 46 ... girder part, 47 ... seat part, 48 ... rise part, 50 ... middle floor support structure, 61 ... fixing tool, 62 ... stair side fixing part, 63 ... beam side fixing part , 100 ... Staircase structure.

Claims (6)

With a beam,
A floor installed below the beam;
A staircase structure comprising a stair unit provided over the beam and the floor,
The stair unit is
A step,
A support base part for supporting the stepped part,
The support base is fixed to the beam via a first fixing structure;
The support base part is a staircase structure that is fixed to the floor part via a second fixing structure having a lower strength against a horizontal force than the first fixing structure. The support base is
A girder that receives the step;
A seat installed on the floor;
A rising portion that extends in the vertical direction and connects the upper end portion of the beam portion and the seat portion;
The first fixing structure fixes the beam and the rising portion,
The step structure according to claim 1, wherein the second fixing structure fixes the floor portion and the seat portion. The support base is
The girder part, the seat part, and the rising part are provided at both ends in the width direction of the step part,
The staircase structure according to claim 2, wherein the first fixing structure fixes the beam and the rising portion at each of the both end portions. The beam is made of H-section steel,
The first fixing structure includes a staircase side fixing portion fixed to the rising portion, and a beam side fixing portion fixed to a lower flange of the beam,
The staircase structure according to claim 2 or 3, wherein the beam-side fixing portion is formed in a plate shape along the lower flange, and is fastened to the lower flange at least at two locations in the horizontal direction.   The staircase structure according to any one of claims 1 to 4, wherein the floor plate of the floor portion is formed of an ALC panel, and the second fixing structure is a screw that penetrates the floor plate. The beam is a frame beam that supports the general floor of the upper floor of the frame,
The floor portion is an intermediate floor portion constituting an intermediate floor between the upper floor and the lower floor,
The intermediate floor portion is supported by an intermediate floor support structure that is connected to the housing and supports the intermediate floor,
The said step part of the said stair unit is formed in 1 to 5 steps | paragraphs according to the difference of the height of the said general floor part and the said intermediate floor part, It is any one of Claims 1-5. Staircase structure.

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