Stage foot fixation structure

Abstract

To improve staircase construction while suppressing damage to a slab 40.SOLUTION: A staircase leg fixing structure comprises: a staircase 50 comprising a concrete beam 30, a slab 40 supported by the concrete beam 30, a bridgeboard 52, a base member 60 provided on a leg of the bridgeboard 52 and placed on the concrete beam 30 and whose both ends extend onto the slab 40 on both sides in the beam width direction of the concrete beam 30; and studs 70 that are provided in the base member 60 and transmit shear forces to the slabs 40 on both sides of the concrete beam 30 in the beam width direction, respectively.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a staircase leg fixing structure. [Background technology]

[0002] BACKGROUND ART A rafter staircase is known (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-095989 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-315033 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when stairs are supported by slabs, if the slab has a low load-bearing capacity, the slab must be reinforced with reinforcing bars or the like, which makes construction time-consuming.

[0005] In consideration of the above, the present invention aims to improve the workability of stairs while suppressing damage to slabs. [Means for solving the problem]

[0006] The staircase leg fixing structure described in claim 1 comprises a staircase having a concrete beam, a slab supported on the concrete beam, a braided beam, a base member attached to the leg of the braided beam, placed on the concrete beam, and having both ends extending onto the slab on both sides of the concrete beam in the beam width direction, and a shear force transmission member attached to the base member, which transmits shear force to the slab on both sides of the concrete beam in the beam width direction.

[0007] According to the staircase leg fixing structure of claim 1, the slab is supported by a concrete beam. The staircase also has a braided beam and a base member. The base member is attached to the leg of the braided beam and placed on the concrete beam. This allows the vertical load of the staircase to be transmitted to the concrete beam mainly via the braided beam and the base member.

[0008] In addition, both ends of the base member extend onto the slabs on both sides of the concrete beam in the beam width direction. Shear force transmission members are attached to this base member. The shear force transmission members transmit shear forces to the slabs on both sides of the concrete beam in the beam width direction. In other words, during an earthquake, horizontal forces acting on the stairs are mainly transmitted as shear forces to the slabs via the shear force transmission members.

[0009] In this way, in this invention, the vertical load of the stairs is borne by the concrete beams, and the horizontal force (shear force) acting on the stairs during an earthquake is borne by the slab. Therefore, since the vertical load of the stairs is borne by the concrete beams, reinforcement of the slab is not required or can be reduced. Therefore, the workability of the stairs is improved.

[0010] Furthermore, even if it is not possible to drive anchors into the concrete beams to transmit shear force, for example because the reinforcement of the concrete beams is too dense, the slab can handle the horizontal force acting on the stairs during an earthquake.

[0011] The staircase leg fixing structure according to claim 2 is the staircase leg fixing structure according to claim 1, wherein the base member is supported by the concrete beam in a state where it is floating above the slab.

[0012] According to the staircase foot fixing structure of claim 2, the base member is supported by the concrete beam while floating above the slab. This more reliably prevents the vertical load of the stairs from being transmitted to the slab via the base member. This eliminates the need for slab reinforcement or further reduces the need for slab reinforcement. This improves the ease of construction of the stairs.

[0013] The staircase leg fixing structure described in claim 3 is the staircase leg fixing structure described in claim 1 or claim 2, in which a hole is formed on the upper surface of the slab, and the shear force transmission member extends downward from the base member and is embedded in a cement-based filler filled in the hole.

[0014] According to the staircase foot fixing structure of claim 3, a hole is formed in the upper surface of the slab. The shear force transmission member extends downward from the base member and is embedded in the cement-based filler filled in the hole. This allows the horizontal force acting on the stairs during an earthquake to be transmitted from the base member to the slab via the shear force transmission member and the cement-based filler.

[0015] Furthermore, with the present invention, it is sufficient to form a hole in the slab, and there is no need to chip off a predetermined area of ​​the slab. Therefore, damage to the slab reinforcement is suppressed, and workability is further improved. [Effects of the Invention]

[0016] As described above, according to the present invention, it is possible to improve the workability of stairs while suppressing damage to slabs. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a plan view showing a concrete beam and a slab to which a staircase foot fixing structure according to one embodiment is applied. FIG. [Figure 2] FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. [Figure 4] 4 is a cross-sectional view corresponding to FIG. 3 showing a construction process of a staircase leg fixing structure according to one embodiment. [Figure 5] 4 is a cross-sectional view corresponding to FIG. 3 showing a construction process of a staircase leg fixing structure according to one embodiment. [Figure 6] 4 is a cross-sectional view corresponding to FIG. 3 showing a construction process of a staircase leg fixing structure according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, a staircase leg fixing structure according to one embodiment will be described with reference to the drawings.

[0019] (Stair leg fixed structure) 1 shows a concrete beam 30, a slab 40, and a staircase 50 to which the staircase leg fixing structure according to this embodiment is applied. Note that, although the following describes an example in which a new staircase 50 is constructed for an existing concrete beam 30 and slab 40, this embodiment can also be applied to a newly constructed concrete beam 30 and slab 40.

[0020] (concrete beam) 2, the concrete beam 30 is, for example, a foundation beam buried in the ground 10. The concrete beam 30 is made of reinforced concrete. A plurality of main beam reinforcements 32 and a plurality of shear reinforcement bars 34 are buried inside the concrete beam 30.

[0021] As shown in Fig. 1, a concrete beam 30 is erected on an adjacent column 20 via a footing 22. A horizontal haunch 30A is provided at the end of the concrete beam 30, and the width of the haunch 30A increases in accordance with the footing 22. A slab 40 is provided on top of the concrete beam 30.

[0022] The concrete beam 30 is not limited to a reinforced concrete structure, but may be a steel-framed reinforced concrete structure. The horizontal haunch portion 30A may be omitted as appropriate.

[0023] (Slab) As shown in Figure 2, the slab 40 is made of reinforced concrete. The slab 40 is a structural slab laid on the ground 10 and forms the floor of the lowest floor of the structure. The slab 40 protrudes from the concrete beam 30 on both sides in the beam width direction (direction of arrow W). The top surface of the slab 40 is flush with the top surface of the concrete beam 30. A staircase 50 is provided on the slab 40.

[0024] The upper surface of the slab 40 and the upper surface of the concrete beam 30 do not necessarily have to be flush with each other, and there may be a step between the upper surface of the slab 40 and the upper surface of the concrete beam 30.

[0025] (stairs) As shown in Figure 1, the staircase 50 is a steel frame staircase with a girders structure. The staircase 50 is newly constructed (post-construction) on the existing concrete beams 30 and slabs 40. The staircase 50 has a pair of girders 52, a plurality of step plates 54, and a pair of base members 60.

[0026] The pair of girders 52 are formed of steel plates or the like. The pair of girders 52 face each other in the width direction of the staircase 50 and are diagonally spanned between the slab 40 and the framework of the upper floor, such as a slab (not shown). A plurality of step plates 54 are mounted on the pair of girders 52.

[0027] The plurality of step plates 54 are formed from steel plates or the like. These step plates 54 are arranged in a staircase pattern between the pair of girders 52. Note that the pair of girders 52 may be provided with risers or the like.

[0028] (Base material) The legs (lower ends) of the pair of girders 52 are arranged on the main body (general portion) 30B that is separated from the horizontal haunch portion 30A of the concrete beam 30. A base member 60 is provided on each of the legs of the pair of girders 52.

[0029] 2 and 3, the base member 60 is formed of an H-shaped steel. The base member 60 has an upper flange portion 62 and a lower flange portion 64 that face each other in the vertical direction, and a web portion 66 that connects the upper flange portion 62 and the lower flange portion 64. The base member 60 is also provided with a plurality of stiffeners 68 as appropriate. The lower flange portion 64 is an example of a base plate.

[0030] 2, the base member 60 is disposed in a direction intersecting the concrete beam 30, and crosses the main body 30B of the concrete beam 30 in a plan view. An intermediate portion 60M in the longitudinal direction (direction of arrow W) of the base member 60 is placed on the upper surface of the concrete beam 30 via a raising base 42 made of mortar, grout, or the like. As a result, the vertical load N of the braided beam 52 is transmitted to the main body 30B of the concrete beam 30 via the intermediate portion 60M of the base member 60 and the raising base 42.

[0031] Both longitudinal ends 60E of the base member 60 extend from the main body 30B of the concrete beam 30 onto the slab 40 on both sides in the beam width direction. A gap is formed between the underside of each end 60E of the base member 60 and the upper surface of the slab 40. In other words, the base member 60 has both end portions 60E floating above the slab 40, and its middle portion 60M is supported by the main body 30B of the concrete beam 30 via the raising platform 42.

[0032] Studs 70 are provided on both longitudinal ends of the base member 60. The studs 70 protrude downward from the underside of the lower flange portion 64 of the base member 60. The studs 70 are inserted into holes 44 formed in the upper surface of the slab 40. The studs 70 are an example of shear force transmission members.

[0033] The hole 44 is a circular through-hole that penetrates the slab 40 in the thickness direction. The ground 10 below the hole 44 is partially excavated through the hole 44. As a result, a construction space 12 is formed below the hole 44. The underside of the slab 40 is exposed in this construction space 12. A bottom formwork 86 (see FIG. 3) of the formwork equipment 80 is arranged in the construction space 12.

[0034] 3, the formwork tool 80 is a tool that installs a bottom formwork 86 on the underside of the slab 40 from above the slab 40 through the holes 44. The formwork tool 80 has a shaft 82, a plurality of opening and closing frames 84, a bottom formwork 86, a sealing material 88, a plurality of links 90, and a slider 92.

[0035] The shaft 82 can be inserted into the hole 44. A plurality of opening and closing frames 84 are arranged around the shaft 82. One end of each of the opening and closing frames 84 is rotatably connected to the tip end of the shaft 82. A sheet-like bottom formwork 86 that covers the hole 44 from below the slab 40 is attached to each of the opening and closing frames 84.

[0036] A sealing material 88 is provided on the outer periphery of the bottom formwork 86 to seal the gap between the underside of the slab 40 and the bottom formwork 86. The sealing material 88 is formed in a ring shape along the outer periphery of the bottom formwork 86, and is capable of adhering to the underside of the slab 40 while surrounding the hole 44.

[0037] One end of a link 90 is rotatably connected to the middle of each opening / closing frame 84. The other end of the link 90 is rotatably connected to a slider 92. The slider 92 is slidably attached to the shaft 82. By sliding the slider 92 along the shaft 82, the bottom formwork 86 can be opened and closed like an umbrella. The bottom formwork 86 closes the hole 44 formed in the slab 40 from the underside of the slab 40.

[0038] The holes 44 in the slab 40 are filled with a cement-based filler 46 such as mortar or grout, with the tip ends of the studs 70 inserted. As a result, the tip ends (lower ends) of the studs 70 are embedded in the cement-based filler 46. The base member 60 and the slab 40 are joined via the studs 70 so that shear forces can be transmitted.

[0039] In addition, it is preferable to form a gap between the underside of the base member 60 and the upper end of the cement-based filler 46 so that vertical load N is not transmitted from the underside of both ends of the base member 60 to the slab 40 via the cement-based filler 46.

[0040] (Construction method for fixing staircase legs) Next, an example of a construction method for the staircase leg fixing structure according to this embodiment will be described.

[0041] 4 shows an existing slab 40 with holes 44 formed therein. First, before forming the holes 44 in the slab 40, the slab 40 is X-rayed on both sides of the existing concrete beam 30 (see FIG. 2) in the beam width direction using an X-ray device (not shown) to confirm the arrangement of the slab reinforcement (not shown).

[0042] Next, a hole 44 is formed in the slab 40 using a core drilling device (not shown), while avoiding the slab reinforcement. Next, an excavation tool (not shown) is inserted into the hole 44 from above the slab 40, and the ground 10 below the slab 40 is excavated to form a construction space 12.

[0043] Next, as shown in Figure 5, the formwork tool 80 with the bottom formwork 86 closed is inserted into the hole 44 from above the slab 40. Next, as shown in Figure 6, the slider 92 is slid upward along the shaft 82 to open the bottom formwork 86 within the construction space 12. In this state, the shaft 82 is pulled upward, and the sealing material 88 provided on the bottom formwork 86 is brought into close contact with the underside of the slab 40. As a result, the hole 44 is sealed from the underside of the slab 40 by the bottom formwork 86.

[0044] 2, the base member 60 is placed on the slab 40 via a temporary platform (not shown). At this time, the base member 60 is positioned relative to the concrete beam 30 so that the base member 60 crosses the main body 30B of the concrete beam 30 in a plan view, and the studs 70 provided on both ends of the base member 60 are inserted into the holes 44 in the slab 40.

[0045] Next, mortar or the like is filled into the gap between the lower surface of the middle portion 60M of the base member 60 and the upper surface of the main body portion 30B of the concrete beam 30 and hardened to form the raising base 42. As a result, the middle portion 60M of the base member 60 is supported on the main body portion 30B of the concrete beam 30 via the raising base 42.

[0046] Additionally, the holes 44 in the slab 40 into which the studs 70 have been inserted are filled with cement-based filler 46 and allowed to harden. This embeds the studs 70 in the cement-based filler 46. As a result, both ends of the base member 60 are joined to the slab 40 via the studs 70 so that shear force can be transmitted. Thereafter, the temporary mounting base is removed as appropriate.

[0047] The construction method of the staircase leg fixing structure according to this embodiment is not limited to the above. For example, the construction of the cement-based filler 46 may be carried out before or after the construction of the elevation platform 42, or in parallel with the construction of the elevation platform 42.

[0048] (action) Next, the operation of this embodiment will be described.

[0049] Generally, when a staircase 50 is supported by a slab 40, if the slab 40 has a low load-bearing capacity, the slab 40 may be damaged. To address this issue, for example, a predetermined area of ​​the slab 40 may be chipped away and new reinforcing bars or the like may be embedded in the slab 40. However, this requires a lot of work. Furthermore, there is a possibility that existing slab bars or the like may be damaged when the slab 40 is chipped away.

[0050] 2, in this embodiment, a pair of base members 60 are provided on the legs of a pair of girders 52 of the staircase 50. The pair of base members 60 are arranged across the main body 30B of the concrete beam 30 in a plan view, and their longitudinal middle portions 60M are placed on the main body 30B of the concrete beam 30 via the raising platform 42.

[0051] As a result, the vertical load N of the stairs 50 is transmitted to the main body 30B of the concrete beam 30 mainly via the pair of braced girders 52 and the pair of base members 60.

[0052] Furthermore, both longitudinal ends 60E of the base member 60 extend onto the slab 40 on both sides in the beam width direction of the main body 30B of the concrete beam 30. Studs 70 are provided on both longitudinal ends of the base member 60. The studs 70 extend downward from the underside of the lower flange portion 64 of the base member 60 and are embedded in the cement-based filler 46 filled in the holes 44 in the slab 40.

[0053] As a result, during an earthquake, the horizontal force F acting on the stairs 50 is transmitted as a shear force mainly from the base member 60 to the slab 40 via the studs 70 and the cement-based filler 46. In other words, in this embodiment, the vertical load N of the stairs 50 is borne by the concrete beams 30, and the horizontal force (shear force) F acting on the stairs 50 during an earthquake is borne by the slab 40.

[0054] In this manner, in this embodiment, the vertical load N of the stairs 50 is borne by the concrete beams 30, so reinforcement of the slab 40 is not required or the reinforcement of the slab 40 is reduced. Therefore, the workability of the stairs 50 is improved.

[0055] Furthermore, even if it is not possible to drive anchors that transmit shear force into the concrete beam 30 due to reasons such as the reinforcement of the concrete beam 30 being congested, such as the horizontal haunch portion 30A, the horizontal force F acting on the stairs 50 during an earthquake can be handled by the slab 40.

[0056] Furthermore, in this embodiment, it is sufficient to form the holes 44 in the slab 40, and there is no need to chip a predetermined area of ​​the slab 40. Therefore, damage to the slab reinforcement of the slab 40 is suppressed, and workability is further improved.

[0057] The pair of base members 60 have their both end portions 60E floating above the upper surface of the slab 40, and their middle portions 60M are supported by the main body portion 30B of the concrete beam 30 via the raising bases .

[0058] This more reliably prevents the vertical load N of the stairs 50 from being transmitted from both end portions 60E of the base member 60 to the slab 40. This makes it unnecessary to reinforce the slab 40, or makes it possible to further reduce the reinforcement required for the slab 40. This further improves the workability of the stairs 50.

[0059] (Variation) Next, a modification of the above embodiment will be described.

[0060] In the above embodiment, the formwork for the hole 44 in the slab 40 is the formwork fixture 80. However, the formwork for the hole 44 in the slab 40 is not limited to the formwork fixture 80 and can be changed as appropriate. Also, for example, if there is a work space such as an equipment room or living room below the slab 40, it is possible to block the hole 44 from below the slab 40 with conventional formwork or the like.

[0061] Furthermore, in the above embodiment, the holes 44 penetrate the slab 40, but the holes 44 do not have to penetrate the slab 40. In this case, the bottom formwork is not required.

[0062] Furthermore, in the above embodiment, the base member 60 is supported by the concrete beam 30 while floating above the slab 40. However, it is sufficient that the vertical load N transmitted from the stairs 50 to the concrete beam 30 is relatively larger than the vertical load N transmitted from the stairs 50 to the slab 40; for example, the base member 60 may be in contact with the slab 40, or a buffer material or the like may be provided between the base member 60 and the slab 40. Furthermore, the raising platform 42 may be provided as needed and may be omitted as appropriate.

[0063] In the above embodiment, the base member 60 is provided on the main body portion 30B of the concrete beam 30. However, the base member 60 is not limited to being provided on the main body portion 30B of the concrete beam 30, and may be provided on the horizontal haunch portion 30A.

[0064] In addition, in the above embodiment, the shear force transmission members are the studs 70. However, the shear force transmission members are not limited to the studs 70, and for example, anchors or the like that protrude from the upper surface of the slab 40 may be attached to the base member 60.

[0065] In the above embodiment, the base member 60 is formed of an H-shaped steel. However, the base member is not limited to an H-shaped steel, and may be formed of, for example, an I-shaped steel, a T-shaped steel, a square steel pipe, etc. Furthermore, the base member is not limited to a steel frame construction, and may be formed of, for example, reinforced concrete construction.

[0066] In the above embodiment, the concrete beams 30 are foundation beams. However, the concrete beams are not limited to foundation beams, and may be beams on the ground floor, for example.

[0067] Although one embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and one embodiment and various modified examples may be used in appropriate combination, and it goes without saying that the present invention can be implemented in various forms as long as it does not deviate from the gist of the present invention. [Explanation of symbols]

[0068] 30 Concrete beam 40 Slabs 44 holes 46 Cement-based filler 50 stairs 52 Slats 60 Base material 60E Both ends (both ends of the base member) 70 Stud (shear force transmission member)

Claims

1. Concrete beams and a slab supported by the concrete beam; a staircase having a slab and a base member provided at the leg of the slab, placed on the concrete beam, and having both ends extending onto the slab on both sides of the concrete beam in the beam width direction; Shear force transmission members provided on the base member and configured to transmit shear force to the slabs on both sides of the concrete beam in the beam width direction; A staircase leg fixing structure comprising:

2. The base member is supported by the concrete beam in a state where it is floating above the slab. The staircase leg fixing structure according to claim 1.

3. A hole is formed in the top surface of the slab, The shear force transmission member extends downward from the base member and is embedded in the cement-based filler material filled in the hole. The staircase leg fixing structure according to claim 1 or 2.

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