U-shaped stairs

Abstract

To suppress restrictions that an outdoor dog-legged staircase has on an installation place of an opening part.SOLUTION: A dog-legged staircase (20) is installed contiguously outside a building (1). The dog-legged staircase (20) has a rectangular outline consisting of a first short side (91), a second short side (92), and a pair of long sides (93 and 94) viewed from above. The first short side (91) is provided along an outer wall (16) of the building (1). The second short side (92) is apart from the outer wall (16). The long sides (93 and 94) are perpendicular to the outer wall (16).SELECTED DRAWING: Figure 4

Description

Technical Field

[0004] , ,

[0005] , , , ,

[0007] , , A rigid frame structure (40) erected parallel to the outer wall (16) of the building (1) along the second short side (92), a plurality of pairs of support beams (21 and 22) extending from the beams (6) of each floor of the building (1) toward the rigid frame structure (40) along the long sides (93 and 94), a plurality of horizontal members (24) installed between the ends of the plurality of pairs of support beams (21 and 22), landings (30) provided on the plurality of pairs of support beams (21 and 22) and the plurality of horizontal members (24), and the ends of the plurality of pairs of support beams (21 and 22) or the plurality The structure comprises: multiple pairs of lower girders (50) that are diagonally downward from each of the horizontal members (24) to the rigid frame structure (40), parallel to the long sides (93 and 94) and parallel to each other; multiple pairs of upper girders (60) that are diagonally upward from the ends of the multiple pairs of support beams (21 and 22) or each of the multiple horizontal members (24) to the rigid frame structure (40), parallel to the long sides (93 and 94) and parallel to each other; and intermediate landings (70) provided on the lower girders (50) and the upper girders (60) closer to the rigid frame structure (40). , , Viewed from above, it has a rectangular outline consisting of a first short side (91) along the outer wall (16) of the building (1), a second short side (92) away from the outer wall (16), and a pair of long sides (93 and 94) perpendicular to the outer wall (16), ,

[0006] ,

[0001] The present invention relates to a folding staircase.

Background Art

[0002] Patent Document 1 discloses an outdoor folding staircase adjacent to the outer wall of an apartment building. This folding staircase is a steel-frame staircase. The side girders of the folding staircase are provided along the outer wall of the apartment building, and the ascending and descending directions of the folding staircase are in the direction along the outer wall of the apartment building.

Prior Art Documents

Patent Documents

[0008] According to the invention of claim 2, a return staircase (20) as described in claim 1 is provided, characterized in that the direction of ascending and descending the stairs is along the long sides (93 and 94).

[0009] According to the invention of claim 2 described above, the constraints that the return staircase (20) imposes on the location of the opening in the exterior wall (16) can be reduced.

[0010] According to the invention of claim 3, A switchback staircase (20) made of steel is installed adjacent to the outside of the building (1), and a rigid frame structure (40) erected parallel to the outer wall (16) of the building (1) along the second short side (92), a plurality of pairs of support beams (21 and 22) extending from the beams (6) of each floor of the building (1) toward the rigid frame structure (40) along the long sides (93 and 94), a plurality of horizontal members (24) installed between the ends of the plurality of pairs of support beams (21 and 22), landings (30) provided on the plurality of pairs of support beams (21 and 22) and the plurality of horizontal members (24), and the plurality of pairs of support The structure comprises: multiple pairs of lower girders (50) that are diagonally downward from the ends of the supporting beams (21 and 22) or each of the multiple horizontal members (24) to the rigid frame structure (40), parallel to the long sides (93 and 94) and parallel to each other; multiple pairs of upper girders (60) that are diagonally upward from the ends of the multiple pairs of supporting beams (21 and 22) or each of the multiple horizontal members (24) to the rigid frame structure (40), parallel to the long sides (93 and 94) and parallel to each other; and intermediate landings (70) provided on the lower girders (50) and upper girders (60) closer to the rigid frame structure (40). A return staircase (20) characterized by the above is provided.

[0013] Claim 4 According to the invention, Any one of items 1 through 3 A return staircase (20) is provided, characterized in that it comprises a plurality of braces (27) installed between the plurality of pairs of support beams (21 and 22).

[0014] The above Claim 4 According to the invention, the brace (27) reinforces the support beams (21 and 22) so that they can withstand bending moments due to horizontal loads. Therefore, the brace (27) contributes to narrowing the width of the support beams (21 and 22).

[0015] Claim 5 According to the invention, Any one of items 1 through 3The folding staircase (20) according to the above, wherein one end of the upper beam (60) and the lower beam (50) is fixed to the ramen structure (40), and the other ends of the upper beam (60) and the lower beam (50) are fixed to the support beams (21 and 22) or the horizontal member (24), is provided.

[0016] According to the invention as described above in the claims 5 According to the invention according to the claim, by fixing both ends of the upper beam (60) and the lower beam (50) to the ramen structure (40) and the support beam (21 or 22) or the horizontal member (24) respectively, the horizontal force can be transmitted. Therefore, it is not necessary to install braces between these upper beam (60) and lower beam (50).

[0017] According to the invention of claim 6, the return staircase described in claim 5, wherein the rigid frame structure (40) is erected vertically at a position away from the outer wall (16) of the building (1) and has a pair of columns (41, 42) arranged in a direction parallel to the outer wall (16) of the building (1), and a plurality of beams (43) horizontally installed between the pair of columns (41, 42) and arranged in the vertical direction, with one end of one of the lower girders (50) of each pair fixed to the joint between the column (42) and the beam (43), and the other end of the one lower girder (50) being at the tip of one of the support beams (22) of each pair A folding staircase is provided, characterized in that it is fixed, one end of the other lower girder (50) of each pair of lower girders (50) is fixed to the beam (43), the other end of the other lower girder (50) is fixed to the horizontal member (24), one end of one upper girder (60) of each pair of upper girders (60) is fixed to the joint between the column (41) and the beam (43), the other end of the one upper girder (60) is fixed to the tip of the other support beam (21) of each pair of support beams (21, 22), one end of the other upper girder (60) of each pair of upper girders (60) is fixed to the beam (43), and the other end of the other upper girder (60) is fixed to the horizontal member (24). Claim 7 According to the invention according to the claim, there is provided a folding staircase which is the folding staircase (20) according to any one of claims 1 to 3, wherein the installation height of the beam (6) of the building (1) is the structural floor height of each floor of the building (1).

Effect of the Invention

[0018] According to the present invention, it is possible to suppress the restrictions imposed by the folding staircase on the installation location of the opening of the outer wall.

Brief Description of the Drawings

[0019] [Figure 1] FIG. 1 is an east elevation view showing a building. [Figure 2] FIG. 2 is a west elevation view showing a building. [Figure 3] FIG. 3 is a south elevation view showing the ramen structure of a building. [Figure 4] FIG. 4 is a detailed view showing the ramen structure of the southwestern part of the second floor of a building. [Figure 5] FIG. 5 is a perspective view showing the skeleton of a folding staircase. [Figure 6] FIG. 6 is a perspective view showing the skeleton of a folding staircase. [Figure 7] Figure 7 is a south elevation view showing the rigid frame structure of the return staircase. [Figure 8] Figure 8 is a cross-sectional view taken along the line VIII-VIII shown in Figure 4, viewed in the direction of the arrow. [Figure 9] Figure 9 is a cross-sectional view taken along the line VIII-VIII shown in Figure 4, viewed in the direction of the arrow. [Modes for carrying out the invention]

[0020] Embodiments will be described below with reference to the drawings. The features and technical effects of the embodiments will be understood from the following detailed description and drawings. However, the scope of the present invention is not limited to the embodiments disclosed below. The scope of the present invention is not limited to the examples in the drawings, as the drawings are provided for illustrative purposes only.

[0021] Figure 1 is the east elevation view of the building, and Figure 2 is the west elevation view of the building. Note that the orientation of the building can be modified depending on the site. The structure consists of building 1 and a return staircase 20.

[0022] [1. Buildings] Building 1 is a steel-framed building, more specifically a building with a steel rigid frame structure. Building 1 is six stories tall. The number of stories in Building 1 is not limited to six, as long as it is two stories or more. Building 1 comprises a foundation, a rigid frame structure, exterior walls, and slabs for each floor. The foundation is fixed to the ground. The rigid frame structure is assembled on the foundation. The exterior walls are attached to the outer perimeter of the rigid frame structure. The exterior walls separate the inside and outside of Building 1. The slab for the first floor is laid on the foundation, and the slabs for the second floor and above are laid on the beams of the rigid frame structure.

[0023] Figure 3 is a south elevation view showing the framework of the rigid frame structure of Building 1. Figure 4 is a floor plan showing the rigid frame structure of the southwestern part of the second floor of Building 1. The rigid frame structure of Building 1 has columns 2-5, multiple main beams 6, multiple main beams 7, multiple main beams 8, multiple main beams 9, multiple secondary beams 10 and multiple secondary beams 11. The rigid frame structure has columns and beams other than columns 2-5, main beams 6-9 and secondary beams 10 and 11, but these columns and beams are far from the return staircase 20, so their illustration is omitted.

[0024] Columns 2-5 are erected vertically on the foundation. Column 2 is located at the southwest corner of building 1. Column 3 is located east of column 2, along the south-facing exterior wall 16 which forms the southwest corner of building 1. Column 4 is located north of column 2, along the west-facing exterior wall 17 which forms the southwest corner of building 1. Column 5 is located east of column 4 and north of column 3, away from columns 3 and 4. Column 5 is located diagonally opposite column 2. Columns 2-5 are rectangular steel pipe columns. Main beam 6 is installed horizontally between columns 2 and 3 at the structural floor height of each floor. Main beam 7 is installed horizontally between columns 2 and 4 at the structural floor height of each floor. Main beam 8 is installed horizontally between columns 4 and 5 at the structural floor height of each floor. Main beam 9 is installed horizontally between columns 3 and 5 at the structural floor height of each floor. Main beams 6-9 are H-shaped steel beams. Secondary beams 10 and 11 are horizontally installed between main beams 6 and 8 at the structural floor height of each floor, and are also installed parallel to main beams 7 and 9. Secondary beams 10 and 11 are H-shaped steel beams. Exterior wall 16 is attached to columns 2 and 3 and main beam 6, and exterior wall 17 is attached to columns 2 and 4 and main beam 7. Exterior wall 16 forms the south face of building 1, and exterior wall 17 forms the west face of building 1.

[0025] [2. A U-shaped staircase] As shown in Figures 1 and 2, the switchback staircase 20 is a steel staircase. The switchback staircase 20 is installed on the outside of building 1, particularly adjacent to the south side of building 1. The switchback staircase 20 is used as an escape staircase. The switchback staircase 20 leads to each floor from the 1st to the 5th floor of building 1. As shown in Figure 4, the switchback staircase 20 has a rectangular outline when viewed from above, consisting of a first short side 91, a second short side 92, and a pair of long sides 93, 94. The first short side 91 runs along the exterior wall 16 of building 1, the second short side 92 moves away from the exterior wall 16 of building 1 towards the south, and the pair of long sides 93, 94 are perpendicular to the exterior wall 16. The direction of ascent and descent on the switchback staircase 20 is along the long sides 93, 94 of the rectangular outline.

[0026] Figures 5 and 6 are perspective views showing the framework of the first to third floors of the U-shaped staircase 20. Figure 7 is a south elevation view showing the rigid frame structure 40 of the U-shaped staircase 20. Figures 8 and 9 are cross-sectional views showing the section along line VIII-VIII shown in Figure 4, viewed in the direction of the arrow. Figure 8 mainly shows the first to third floors of the U-shaped staircase 20, and Figure 9 mainly shows the third to fifth floors of the U-shaped staircase 20.

[0027] As shown in Figures 4 to 9, the U-shaped staircase 20 comprises multiple pairs of support beams 21, 22, multiple pairs of horizontal members 23, 24, multiple braces 27, multiple landings 30, a rigid frame structure 40, multiple pairs of lower stringers 50, multiple sets of treads 55, multiple sets of risers 56, multiple pairs of upper stringers 60, multiple sets of treads 65, multiple sets of risers 66, multiple intermediate landings 70, and a top-level auxiliary stringer 69 (see Figure 1).

[0028] [2-1. Landings on each floor from the 2nd to the 5th floor] The support beams 21 and 22, horizontal members 23 and 24, and braces 27 are located slightly below the floor level of each floor from the second floor upwards. Support beam 21 is fixed to the joint between column 2 and main beam 6 at the structural floor height of each floor from the first to the fourth floor. Support beam 21 extends horizontally southward along its long side 93 from the joint between column 2 and main beam 6 and penetrates the south-facing exterior wall 16. Support beam 21 is positioned as an extension of main beam 7 to the south. Support beam 22 is fixed to main beam 6 at the structural floor height of each floor from the first to the fourth floor. Support beam 22 extends horizontally southward along its long side 94 from main beam 6 and penetrates the south-facing exterior wall 16. Support beam 22 is positioned as an extension of secondary beam 10 to the south.

[0029] The support beams 21 and 22 are installed parallel to each other. The support beams 21 and 22 are H-shaped steel beams having a weak axis and a strong axis perpendicular to their direction of extension, with the strong axis of the support beams 21 and 22 being horizontal and the weak axis of the support beams 21 and 22 being vertical. The bending stiffness of the support beams 21 and 22 around the strong axis is higher than the bending stiffness of the support beams 21 and 22 around the weak axis.

[0030] Horizontal members 23 are installed horizontally between support beams 21 and 22 at the structural floor height of each floor from the 1st to the 4th floor. Horizontal members 23 are positioned close to the outer exterior wall 16. Horizontal members 24 are installed horizontally between the tip of support beam 21 and the tip of support beam 22 at the structural floor height of each floor from the 1st to the 4th floor. Horizontal members 23 and 24 are installed parallel to each other. Horizontal members 23 and 24 are H-shaped steel. Braces 27 are installed between the diagonals of the rectangular frame formed by support beams 21 and 22 and horizontal members 23 and 24 at the structural floor height of each floor from the 1st to the 4th floor. Braces 27 reinforce support beams 21 and 22 so that they can withstand bending moments around the weak axis due to horizontal loads. Therefore, braces 27 contribute to narrowing the width of support beams 21 and 22. As the support beams 21 and 22 are passed through through holes formed in the outer wall 16, the brace 27 contributes to narrowing the width of these through holes.

[0031] The landings 30 are fixed on the support beams 21, 22 and horizontal members 23, 24 at the floor level of each floor from the 2nd to the 5th floor. The landings 30 on each floor from the 2nd to the 5th floor have a flat upper surface that is aligned with the floor level of each floor from the 2nd to the 5th floor. The landings 30 have a raised frame 31 and floorboards 32. The raised frame 31 is framed with structural steel such as channel steel. The raised frame 31 is fixed on the support beams 21, 22 and horizontal members 23, 24. The floorboards 32 are laid on the raised frame 31. The upper surfaces of the floorboards 32 on each floor from the 2nd to the 5th floor are aligned with the floor level of each floor. As shown in Figures 1, 2, and 3, the landing 39 on the 1st floor is made of a concrete structure.

[0032] A fence is erected along the eastern and western edges of landing 30. In the above explanation, the installation height of the beam 6 to which the support beams 21 and 22 are fixed is the structural floor height of each floor of the building 1. However, the beam 6 may be installed offset above or below the structural floor height.

[0033] [2-2. Ramen Structure] As shown in Figures 4 to 9, the rigid frame structure 40 is erected on a foundation at a position south of the vertical plane formed by the columns 2, 3 and the main beam 6, and the exterior wall 16. The rigid frame structure 40 is erected along the second short side 92, parallel to the vertical plane formed by the columns 2, 3 and the main beam 6, and the exterior wall 16.

[0034] The rigid frame structure 40 has columns 41, 42 and multiple beams 43. Columns 41 and 42 are rectangular steel pipe columns, and beams 43 are H-shaped steel. Column 41 is erected vertically on the foundation on the opposite side of column 4 with respect to column 2 at the corner of building 1. Column 41 is located south of column 2 and is positioned where the exterior wall 17 extends south. Column 42 is erected vertically on the foundation at a location east of column 41. Column 42 is positioned where the secondary beam 10 extends south. The vertical plane formed by columns 41 and 42 is parallel to the vertical plane formed by columns 2, 3 and the main beam 6, and to the exterior wall 16. Beams 43 are horizontally installed between columns 41 and 42 at the midpoint of the floor height of each floor. Beams 43 support the intermediate landing 70 from below.

[0035] In the following explanation, the landing 30 on the floor half a floor above beam 43 and intermediate landing 70 will be referred to as the upper landing 30, and the landing 30 or 39 on the floor half a floor below beam 43 and intermediate landing 70 will be referred to as the lower landing 30 or 39. The support beams 21, 22 and horizontal members 23, 24 that support the upper landing 30 will be referred to as the upper support beams 21, 22 and upper horizontal members 23, 24, and the support beams 21, 22 and horizontal members 23, 24 that support the lower landing 30 will be referred to as the lower support beams 21, 22 and lower horizontal members 23, 24.

[0036] [2-3. Between the 2nd and 3rd floors] Between the second and third floors, a pair of lower girders 50 are arranged parallel to each other and spaced apart from east to west in the eastern half of the area inside the rectangular contour formed by the short sides 91, 92 and the long sides 93, 94, while a pair of upper girders 60 are arranged parallel to each other and spaced apart from east to west in the western half of the area inside the rectangular contour. The pair of lower girders 50 are parallel to the long sides 93, 94 of the rectangular contour, and the eastern lower girder 50 of the pair is aligned with the long side 94 of the rectangular contour. The pair of upper girders 60 are parallel to the long sides 93, 94 of the rectangular contour, and the western upper girder 60 of the pair is aligned with the long side 93 of the rectangular contour.

[0037] Of the pair of lower girders 50, the eastern lower girder 50 is stretched diagonally across the horizontal plane from the tip of the lower floor support beam 22 southward to the joint between the beam 43 and the column 42, with its northern end fixed to the tip of the lower floor support beam 22 and its southern end fixed to the joint between the beam 43 and the column 42. The western lower girder 50 is stretched diagonally across the horizontal plane from the lower floor horizontal member 24 southward to the beam 43, with its northern end fixed to the lower floor horizontal member 24 and its southern end fixed to the beam 43.

[0038] These lower girders 50 have a slanted section 51 that extends diagonally upward toward the south from the lower floor horizontal member 24 to the intermediate landing 70, and a horizontal section 52 that extends horizontally toward the south from the southern end of the slanted section 51 to the beam 43. The northern end of the slanted section 51 of the eastern lower girder 50 is fixed to the tip of the lower floor support beam 22. The northern end of the slanted section 51 of the eastern lower girder 50 may also be fixed to the lower floor horizontal member 24. The southern end of the horizontal section 52 of the eastern lower girder 50 is fixed to the joint between the beam 43 and the column 42. The northern end of the slanted section 51 of the western lower girder 50 is fixed to the lower floor horizontal member 24. The southern end of the horizontal section 52 of the western lower girder 50 is fixed to the beam 43.

[0039] Multiple treads 55 and multiple risers 56 are arranged between the slanted portions 51 of the lower beams 50 and are fixed to the slanted portions 51 of the lower beams 50. Note that risers 56 are not required. A fence is erected on the upper edge of these lower beams 50.

[0040] Of the pair of upper girders 60, the western upper girder 60 is stretched diagonally across the horizontal plane from the joint between the beam 43 and the column 41 to the tip of the upper floor support beam 21, with its northern end fixed to the tip of the upper floor support beam 21 and its southern end fixed to the joint between the beam 43 and the column 41. The eastern upper girder 60 is stretched diagonally across the horizontal plane from the beam 43 to the upper floor horizontal member 24, with its northern end fixed to the upper floor horizontal member 24 and its southern end fixed to the beam 43.

[0041] These upper girders 60 have a slanted section 61 that extends diagonally downward to the south from the upper floor horizontal member 24 to the intermediate landing 70, and a horizontal section 62 that extends horizontally to the south from the southern end of the slanted section 61 to the beam 43. The northern end of the slanted section 61 of the western upper girder 60 is fixed to the tip of the upper floor support beam 21. The southern end of the horizontal section 62 of the western upper girder 60 is fixed to the joint between the beam 43 and the column 41. The northern end of the slanted section 61 of the eastern upper girder 60 is fixed to the upper floor horizontal member 24. The southern end of the horizontal section 62 of the eastern upper girder 60 is fixed to the beam 43.

[0042] Multiple treads 65 and multiple risers 66 are arranged between the slanted sections 61 of the upper beam 60 and are fixed to the slanted sections 61 of the upper beam 60. Note that risers 66 are not required. A fence is erected on the upper edge of these upper beams 60.

[0043] The intermediate landing 70 is positioned horizontally between the horizontal section 52 of the eastern lower girder 50 and the horizontal section 62 of the western upper girder 60, and is fixed to the horizontal section 52 of the eastern lower girder 50 and the horizontal section 62 of the western upper girder 60. The intermediate landing 70 is laid on and supported by the horizontal section 52 of the western lower girder 50, the horizontal section 62 of the eastern upper girder 60 and the beam 43.

[0044] Fences are erected along the western, eastern, and southern edges of the intermediate landing 70.

[0045] [2-4. Between the 3rd and 4th floors, between the 4th and 5th floors] Similar to the space between the second and third floors, a pair of lower beams 50, multiple treads 55, multiple risers 56, a pair of upper beams 60, multiple treads 65, multiple risers 66, an intermediate landing 70, and a railing are installed between the third and fourth floors.

[0046] Similar to the space between the second and third floors, a pair of lower girders 50, multiple treads 55, multiple risers 56, a pair of upper girders 60, multiple treads 65, multiple risers 66, an intermediate landing 70, and a railing are installed between the fourth and fifth floors. As shown in Figure 1, in addition to these, an auxiliary girder 69 is installed between the fourth and fifth floors. The auxiliary girder 69 is positioned east of the eastern upper girder 60. The auxiliary girder 69 is stretched diagonally across the horizontal plane from the horizontal section 52 of the eastern lower girder 50 northward to the tip of the upper floor support beam 22, with its northern end fixed to the tip of the upper floor support beam 22 and its southern end fixed to the horizontal section 52 of the eastern lower girder 50.

[0047] [2-5. Between the first and second floors] Similar to the space between the second and third floors, a pair of upper beams 60, multiple treads 65, multiple risers 66, an intermediate landing 70, and a railing are installed between the first and second floors.

[0048] Between the first and second floors, a pair of lower girders 50 are arranged parallel to each other and separated from east to west in the eastern half of the area inside the rectangular contour consisting of short sides 91, 92 and long sides 93, 94. The eastern lower girder 50 of the pair of lower girders 50 is aligned with the long side 94 of the rectangular contour. The eastern lower girder 50 of the pair of lower girders 50 is stretched diagonally across the horizontal plane from the lower floor landing 39 southward to the joint between the beam 43 and the column 42, with its northern end fixed to the lower floor landing 39 and its southern end fixed to the joint between the beam 43 and the column 42. The western lower girder 50 is stretched diagonally across the horizontal plane from the lower floor landing 39 southward to the beam 43, with its northern end fixed to the lower floor landing 39 and its southern end fixed to the beam 43. These lower girders 50 have a slanted section 51 that extends diagonally upward to the south from the lower landing 39 to the intermediate landing 70, and a horizontal section 52 that extends horizontally to the south from the southern end of the slanted section 51 to the beam 43. The northern end of the slanted section 51 of these lower girders 50 is fixed to the lower landing 39. The southern end of the horizontal section 52 of the eastern lower girder 50 is fixed to the joint between the beam 43 and the column 41. The southern end of the horizontal section 52 of the western lower girder 50 is fixed to the beam 43. Multiple treads 55 and multiple risers 56 are arranged between the slanted sections 51 of these lower girders 50 and are fixed to the slanted sections 51 of these lower girders 50. Note that risers 56 are not required. A railing is erected on the upper edge of these lower girders 50.

[0049] [3. Advantageous technical effects] (1) As shown in Figure 4, when viewed from above, the U-shaped staircase 20 has a rectangular outline consisting of short sides 91, 92 and long sides 93, 94. The first short side 91 of the rectangular outline is provided along the outer wall 16 of the building 1, and the long side 93 of the rectangular outline is perpendicular to the outer wall 16 of the building 1. Therefore, when viewed from the south, the area occupied by the U-shaped staircase 20 relative to the outer wall 16 of the building 1 is minimized, and the constraints that the U-shaped staircase 20 places on the location of openings in the outer wall 16 are reduced. This contributes to an increase in the degree of freedom in the location of openings. Here, an opening refers to, for example, a window that can be opened and closed.

[0050] (2) The lower girder 50 on the east side is stretched diagonally across the horizontal plane from the tip of the lower floor support beam 22 to the joint between the beam 43 and the column 42, extending southward, and the lower girder 50 on the west side is stretched diagonally across the horizontal plane from the lower floor horizontal member 24 to the beam 43, extending southward. The upper girder 60 on the west side is stretched diagonally across the horizontal plane from the joint between the beam 43 and the column 41 to the tip of the upper floor support beam 21, extending northward, and the upper girder 60 on the east side is stretched diagonally across the horizontal plane from the beam 43 to the upper floor horizontal member 24, extending northward. Therefore, when an earthquake force occurs in the direction of the long side of the return staircase 20, that earthquake force is borne by the rigid frame structure of the building 1 through the multiple lower girders 50, multiple upper girders 60, multiple support beams 21 and multiple support beams 22. Therefore, even if there are no beams extending along the direction of the long side between the rigid frame structure 40 and the main beam 6 of the building 1, the return staircase 20 can withstand the earthquake force.

[0051] (3) The horizontal seismic force is distributed between the rigid frame structure 40 and the rigid frame structure of building 1 according to the direction of the sides of the return staircase. In other words, the seismic force in the direction of the long side is borne by the rigid frame structure of building 1, and the seismic force in the direction of the short side is shared between the rigid frame structure of building 1 and the rigid frame structure 40. As a result, the return staircase 20 can withstand seismic forces in both the short and long sides.

[0052] (4) The southern end of the eastern lower girder 50 is fixed to the joint of the rigid frame structure 40, and the southern end of the western lower girder 50 is fixed to the beam 43 of the rigid frame structure 40. The southern end of the western upper girder 60 is fixed to the joint of the rigid frame structure 40, and the southern end of the eastern upper girder 60 is fixed to the beam 43 of the rigid frame structure 40. Therefore, even if braces are not installed between the pair of lower girders 50 and between the pair of upper girders 60, the horizontal seismic forces generated in the return staircase 20 can be transmitted.

[0053] (5) A brace 27 is installed between the support beam 21 and the support beam 22. The brace 27 reinforces the support beams 21 and 22 so that they can withstand bending moments around the weak axis due to horizontal loads. Therefore, the brace 27 contributes to narrowing the width of the support beams 21 and 22. As the support beams 21 and 22 are passed through through holes formed in the outer wall 16, the brace 27 contributes to narrowing the width of these through holes.

[0054] (6) Building 1 and the return staircase 20 are made of steel frame, and they have high seismic resistance and a long lifespan. Therefore, Building 1 and the return staircase 20 contribute to achieving goals such as "creating cities and communities where people can live" and "SDGs (Sustainable Development Goals)." [Explanation of Symbols]

[0055] 1. Building 6 girder 16. Exterior Wall 20. Shifting Staircase 21,22 Support beam 23,24 Horizontal material 30 Landing 40 Ramen Structure 50 Lower girder 60 Upper digit 70 Intermediate landing 91 First short side 92 Second short side 93,94 Long side

Claims

1. A return staircase, which is a steel frame staircase, has a rectangular outline when viewed from above, consisting of a first short side along the outer wall of the building, a second short side away from the outer wall, and a pair of long sides perpendicular to the outer wall, and is installed adjacent to the outside of the building. A rigid frame structure erected parallel to the outer wall of the building along the second short side, Multiple pairs of support beams extending from the beams of the building toward the rigid frame structure along the long side, Multiple horizontal members are installed between the ends of the aforementioned multiple pairs of support beams, The plurality of support beams and the plurality of horizontal members each have a landing, The ends of the aforementioned multiple pairs of support beams or each of the aforementioned multiple horizontal members are extended diagonally downward to the rigid frame structure, and the multiple pairs of lower girders are parallel to the long side and parallel to each other, Multiple pairs of upper girders are provided, which are diagonally extended upward from the ends of the multiple pairs of support beams or from each of the multiple horizontal members to the rigid frame structure, and are parallel to the long side and parallel to each other. An intermediate landing provided in the lower girder and the upper girder, which is closer to the rigid frame structure, A flip-up staircase characterized by having the following features.

2. A return staircase according to claim 1, The direction of going up and down the stairs is aligned with the aforementioned long side. A U-shaped staircase characterized by its features.

3. It is a switchback staircase made of steel, installed adjacent to the outside of the building. A rigid frame structure erected parallel to the outer wall of the building at a position away from the outer wall of the building, Multiple pairs of support beams extending from the beams of the aforementioned building toward the rigid frame structure, Multiple horizontal members are installed between the ends of the aforementioned multiple pairs of support beams, The plurality of support beams and the plurality of horizontal members each have a landing, The ends of the aforementioned multiple pairs of support beams or each of the aforementioned multiple horizontal members are extended diagonally downward to the rigid frame structure, and multiple pairs of lower girders are parallel to each other, The ends of the aforementioned pairs of support beams or each of the aforementioned pairs of horizontal members are extended diagonally upward to the rigid frame structure, and the upper girders are parallel to each other, An intermediate landing provided in the lower girder and the upper girder, which is closer to the rigid frame structure, A flip-up staircase characterized by having the following features.

4. A folding staircase according to any one of claims 1 to 3, Multiple braces are installed between each of the aforementioned pairs of support beams. A flip-up staircase characterized by having the following features.

5. A folding staircase according to any one of claims 1 to 3, One end of the upper girder and the lower girder are fixed to the rigid frame structure, and the other ends of the upper girder and the lower girder are fixed to the support beam or the horizontal member, respectively. A U-shaped staircase characterized by its features.

6. The return staircase according to Claim 5, The aforementioned ramen structure, A pair of columns are erected vertically at a position away from the outer wall of the building and parallel to the outer wall of the building, A plurality of beams are horizontally erected between the pair of columns and arranged vertically, It has, One end of one of the lower girders of each pair is fixed to the joint between the column and the beam, the other end of the one lower girder is fixed to the tip of one of the support beams of each pair, one end of the other lower girder of each pair is fixed to the beam, and the other end of the other lower girder is fixed to the horizontal member. One end of one of the upper girders of each pair is fixed to the joint between the column and the beam, the other end of the one upper girder is fixed to the tip of the other support beam of each pair, one end of the other upper girder of each pair is fixed to the beam, and the other end of the other upper girder is fixed to the horizontal member. A U-shaped staircase characterized by its features.

7. A folding staircase according to any one of claims 1 to 3, The installation height of the beams in the aforementioned building is the structural floor height of each floor of the building. A U-shaped staircase characterized by its features.

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