JP6836857B2 - Underfloor structure - Google Patents

Description

The present invention relates to an underfloor structure.

In the slab formwork structure disclosed in Patent Document 1 below, a slab is formed by placing concrete on a deck plate in which rib strips are projected downward.

Japanese Unexamined Patent Publication No. 10-325202

However, when a slab is formed using the deck plate of Patent Document 1 and a fire compartment wall is arranged under the slab, if a fire occurs in one of the spaces partitioned by the fire compartment wall, the rib of the deck plate Heat is transmitted along the strips, and there is a risk that the spread of fire will propagate to the other space partitioned by the fire protection compartment wall.

In view of the above facts, an object of the present invention is to provide an underfloor structure capable of suppressing the spread of fire in two spaces separated by a fireproof partition wall.

The underfloor structure according to claim 1 includes a floor slab in which concrete is cast in a steel formwork, a fireproof partition wall provided below the floor slab, and spaces on both sides partitioned by the fireproof partition wall. with spans, have a, and fire heating suppressing member provided in contact with the steel mold, the steel formwork is a deck plate projections and recesses are repeatedly formed, wherein the fire rating The wall is arranged along the direction in which the convex portion and the concave portion repeat .

According to the underfloor structure according to claim 1, a fire heating suppression member is provided across the spaces on both sides partitioned by the fire protection partition wall. As a result, the heat transferred through the steel formwork is endothermic or shielded by the fire heat suppressing member. Therefore, it is possible to suppress the spread of fire between the spaces on both sides partitioned by the fire protection partition wall.

In the underfloor structure according to claim 2, the steel formwork has irregularities, and the fire heating suppression member is an endothermic member provided in a recess opened below the steel formwork.

According to the underfloor structure according to claim 2, since the steel formwork has irregularities, slab concrete can be cast without using support work. Further, a heat absorbing member is provided in a recess opened below the steel formwork. As a result, even if the steel formwork is heated in the event of a fire, the heat absorbing material absorbs the heat, and it is possible to suppress the occurrence of a heat bridge between the spaces on both sides partitioned by the fire protection partition wall.

In the underfloor structure according to claim 3, the fire heating suppression member is a heat shield plate provided in contact with the lower surface of the steel formwork.

According to the underfloor structure according to claim 3, a heat shield plate is provided on the lower surface of the steel formwork. Therefore, even if the steel form is heated, the heat radiation is shielded by the heat shield plate. Therefore, even if heat is transferred from one space side partitioned by the fireproof partition wall to the other space side through the steel formwork, this heat is not easily released into the space.
In the underfloor structure of claim 4, the steel formwork is continuously arranged in front of and behind the fireproof partition wall.
In the underfloor structure of claim 5, the fire heating suppression member is provided at a position separated from the surface of the fire compartment wall by a thickness equal to or greater than the thickness of the fire compartment wall.

According to the underfloor structure according to the present invention, it is possible to suppress the spread of fire in two spaces separated by a fireproof partition wall.

(A) is a vertical sectional view showing an underfloor structure according to the first embodiment of the present invention, and (B) is a sectional view taken along line BB of (A). (A) is a partially enlarged vertical sectional view showing the details of the underfloor structure according to the first embodiment of the present invention, (B) is a sectional view taken along line BB of (A), and (C) is a deck plate. A steel plate to be attached to the underside of. It is sectional drawing which shows the example formed in the shape of a frame. (A) is a partially enlarged vertical sectional view showing an example in which the rib of the deck plate in the underfloor structure according to the first embodiment of the present invention is formed in an I shape, and (B) is an example in which the deck plate is formed in a wavy shape. Is a partially enlarged vertical sectional view showing, (C) is a partially enlarged vertical sectional view showing an example in which a deck plate is formed flat, and (D) is a DD line sectional view in (C). (A) is a partially enlarged vertical sectional view showing the details of the underfloor structure according to the second embodiment of the present invention, and (B) is a sectional view taken along line BB of (A). (A) is a partially enlarged vertical sectional view showing the details of the underfloor structure according to the third embodiment of the present invention, (B) is a sectional view taken along line BB of (A), and (C) is a heat shield. It is a partially enlarged vertical sectional view which shows the example which divided and arranged the plate in front and back of a wall body. (A) is a partially enlarged vertical sectional view showing the details of the underfloor structure according to the comparative example, and (B) is a sectional view taken along line BB of (A).

[First Embodiment]
1 (A) and 1 (B) show the underfloor structure 10 according to the first embodiment of the present invention. The underfloor structure 10 straddles the floor slab 20, the wall body 30 provided below the floor slab 20, and the spaces 12 and 14 on both sides partitioned by the wall body 30, and the floor slab 20 and the wall body 30. It is configured to include a heat absorbing material 42 and a steel plate 44 provided between them.

(Floor slab)
As shown in FIGS. 2A and 2B, the floor slab 20 is a synthetic slab in which concrete 28 is cast on the upper part of the deck plate 22 as a steel formwork.

As shown in FIG. 2B, the deck plate 22 has an uneven shape due to the flat portion 24 and the hollow ribs 26 protruding downward from the flat portion 24. Specifically, the hollow rib 26 is formed integrally with the flat portion 24 by bending a steel plate, and has a triangular shape whose width expands as the distance from the flat portion 24 increases. The inside of the triangular hollow rib 26 is a hollow portion 26B. Further, a plurality of hollow ribs 26 are arranged at regular intervals in a direction substantially orthogonal to the axial direction of the ribs, and a recess 26A is formed between the adjacent hollow ribs 26.

As shown in FIG. 1A, both ends of the deck plate 22 (both ends in the axial direction of the hollow rib 26) are end-closed portions 22A obtained by closing the hollow rib 26, and are mounted on the beam 16. .. Further, the deck plate 22 is arranged so that the extending direction of the hollow rib 26 (the direction indicated by the arrow X in FIG. 2A) is substantially orthogonal to the extending direction of the beam 16.

A slab reinforcement (not shown) is buried inside the concrete 28. This slab reinforcement is laid after the deck plate 22 is placed on the beam 16, and then the concrete 28 is placed. Since the deck plate 22 is provided with the hollow ribs 26 to have an uneven shape, concrete can be cast without using a support.

(Steel plate / endothermic material)
A steel plate 44 is fixed to the lower surface (triangular bottom surface) of the hollow rib 26 of the deck plate 22, and the recess 26A surrounded by the steel plate 44 and the hollow rib 26 is provided as an example of the fire heating suppression member in the present invention. The heat absorbing material 42 is filled.

The steel plate 44 is a flat face material, and is fixed to the lower surface of the hollow rib 26 by using a tapping screw (not shown) to close the lower part of the recess 26A. The means for fixing the steel plate 44 to the hollow rib 26 is not limited to tapping screws, and may be adhesion or welding, or locking claws or the like formed on the steel plate 44 and the hollow rib 26, respectively. Alternatively, as in the steel plate 45 shown in FIG. 2C, a steel plate processed into a groove shape in which the tip of the flange is widened may be fixed by being hooked on the hollow rib 26.

The heat absorbing material 42 is made of concrete and is cast from a through hole 24A formed in the flat portion 24 of the deck plate 22 into a recess 26A surrounded by a hollow rib 26 and a steel plate 44. In the recess 26A, a filler material 47 formed of rock wool, an air tube, a foamable heat insulating material, or the like is arranged in order to block the highly fluid concrete immediately after being placed. The filler material 47 is arranged at a position separated from the surface of the wall body 30, which will be described later, by a thickness D or more of the wall body 30.

Although the endothermic material 42 is made of concrete in the present embodiment, the embodiment of the present invention is not limited to this. For example, a material having a high water content such as mortar, a material having water of crystallization such as gypsum or aluminum hydroxide, or a material having water retention such as a super absorbent polymer material (water-absorbing polymer) can be used.

Further, in the present embodiment, the steel plate 44 is used as a formwork for the concrete forming the heat absorbing material 42, and is left behind even after the concrete is hardened, but the embodiment of the present invention is not limited to this. For example, the steel plate 44 may be removed after the concrete has hardened. Even if the steel plate 44 is removed, the hardened endothermic material 42 is locked by the hollow rib 26 and does not fall.

(Wall body)
The wall body 30 is a dry fireproof partition wall formed by pasting gypsum board 34 on a base material 32 of a lightweight steel frame (LGS).

The base material 32 includes a runner 32A embedded above and below the wall body 30 and extended in the lateral direction, and a stud 32B whose both ends are fitted into the upper and lower runners 32A. The runner 32A at the lower part of the wall body 30 is fixed to the concrete 28 of the floor slab 20 on the floor where the wall body 30 is installed, and the runner 32A at the upper part of the wall body 30 is fixed to the steel plate 44.

The gypsum board 34 is fixed to the runner 32A and the stud 32B with screws, and the thickness and the number of layers are appropriately selected according to the required fire resistance performance. As a result, the wall body 30 divides the lower space of the floor slab 20 into two spaces 12 and 14.

(Action / effect)
In the underfloor structure 10 of the first embodiment, as shown in FIG. 2A, the heat absorbing material 42 is formed in the recess 26A formed between the hollow ribs 26 across the spaces 12 and 14 partitioned by the wall body 30. Is provided. When the hollow rib 26 of the deck plate 22 is heated by a flame or hot air at the time of a fire, heat is transferred along the hollow rib 26 (heat conduction), but this heat is absorbed by the heat absorbing material 42. Therefore, heat propagation between the spaces 12 and 14 partitioned by the wall body 30 can be suppressed. That is, it is possible to suppress the formation of a heat bridge across the spaces 12 and 14.

Further, the runner 32A at the upper part of the wall body 30 is fixed to the steel plate 44 which is a flat face material fixed to the lower surface of the hollow rib 26. Therefore, a gap is unlikely to occur in the upper part of the wall body 30, and the propagation of flames and smoke between the spaces 12 and 14 can be suppressed.

Therefore, according to the underfloor structure 10 of the first embodiment, it is possible to suppress the spread of fire between the spaces 12 and 14 partitioned by the wall body 30.

Further, the heat absorbing material 42 is filled from the through hole 24A formed in the flat portion 24 of the deck plate 22 into the recess 26A surrounded by the hollow rib 26 and the steel plate 44. Therefore, after filling the recess 26A with concrete as the heat absorbing material 42, the concrete 28 arranged on the upper part of the deck plate 22 can be continuously placed without interrupting the work.

Further, since concrete has high fluidity before hardening, it is possible to fill the trapezoidal recess 26A formed between the triangular hollow rib 26 and the steel plate 44 without a gap. Therefore, the heat of the hollow rib 26 is easily absorbed.

On the other hand, for example, the configuration of the floor slab 200 and the wall body 300 in the underfloor structure 100 according to the comparative examples shown in FIGS. 6A and 6B is the floor slab 20 and the wall in the underfloor structure 10 of the first embodiment. It has almost the same structure as the body 30, but does not have the endothermic material 42 (see FIGS. 2A and 2B).

Therefore, a gap V is formed in the recess 260A between the hollow ribs 260 of the deck plate 220. Therefore, when the hollow rib 260 of the deck plate 220 is heated by the flame or hot air at the time of fire, the heat moves along the hollow rib 260 and the heat propagates between the spaces 120 and 140 partitioned by the wall body 300. To do. In order to suppress heat propagation between the spaces 120 and 140, it is necessary to cut out the hollow rib 260.

In the present embodiment, as shown in FIG. 2B, the deck plate 22 provided with the triangular hollow ribs 26 is used as the steel formwork constituting the floor slab 20, but according to the present invention. The embodiment is not limited to this. For example, as shown in FIG. 3A, a deck plate 52 provided with an I-shaped rib 52A may be used instead of the triangular hollow rib 26. Since the rib 52A does not have a hollow portion, the volume of the heat absorbing material 42 filled in the recess between the ribs 52A is increased as compared with the volume of the heat absorbing material 42 filled in the recess 26A between the hollow ribs 26. And can enhance the endothermic effect.

Further, in the present embodiment, the upper portion of the hollow rib 26 is closed, and the hollow rib 26 has a shape that does not come into contact with the concrete 28 cast on the upper portion, but the embodiment of the present invention is limited to this. Absent. For example, as in the deck plate 54 having a corrugated concave-convex shape shown in FIG. 3B, both the convex portion 54A and the concave portion 54B may be configured to be in contact with the concrete 28. As a result, even if the convex portion 54A is heated by the flame or hot air at the time of fire, the heat is absorbed from the convex portion 54A not only to the heat absorbing material 42 but also to the concrete 28, and the heat absorbing effect can be enhanced.

Further, in the present embodiment, the deck plate 22 is configured to have irregularities, but the embodiment of the present invention is not limited to this. For example, the deck plate 56 shown in FIG. 3C may have a flat structure having no unevenness or having small unevenness (approximately 10% or less) with respect to the thickness of the concrete 28. The deck plate 56 is a throw-away formwork with reinforcing bars to which reinforcing bars for slab reinforcement are previously joined in a factory or the like. In this case, the steel plate 46 is installed with a gap below the deck plate 56, and the space between the deck plate 56 and the steel plate 46 is filled with the heat absorbing material 42. As shown in FIG. 3D, the steel plate 46 is formed into a box shape by bending the end portions (the front side and the back side portions of the paper surface in FIG. 3C) and is joined to the deck plate 56. As shown in FIG. 3C, the steel plate 46 can be reinforced by appropriately using hanging bolts 48. Further, instead of the hanging bolt 48, a steel reinforcing member or the like may be welded. If reinforcement is not required, a configuration without a hanging bolt 48 or a reinforcing member may be used.

[Second Embodiment]
(Constitution)
4 (A) and 4 (B) show the underfloor structure 60 according to the second embodiment. In the underfloor structure 60, as in the first embodiment, the floor slab 20 in which concrete 28 is cast on the upper part of the deck plate 22 as a steel formwork, and the wall body 30 provided below the floor slab 20 , Is equipped.

The flat portion 24 of the deck plate 22 is not formed with the through holes 24A (see FIGS. 2A and 2B) in the first embodiment, and the through holes 26C and 26D are formed on the lower surface of the hollow rib 26. ing. Further, the runner 32A constituting the wall body 30 is fixed to the lower surface of the hollow rib 26, and a gap V is formed between the wall body 30 and the flat portion 24 of the deck plate 22.

The gap V can also be filled by cutting out a non-combustible material such as gypsum board along the shape of the gap V and fitting it, and sealing the outer peripheral portion of the fitted portion.

The hollow portion 26B of the hollow rib 26 is filled with a heat absorbing material 42. The endothermic material 42 is injected from the through hole 26C and is blocked by the filler material 47 which has been injected from the through holes 26D arranged on both sides of the through hole 26C in advance and is effective, and fills the hollow portion 26B in the upper part of the wall body 30. Will be done.

The through hole 26C is not always necessary. For example, when the deck plate 22 is manufactured, the hollow rib 26 is formed by involving a solid heat absorbing material, or after the deck plate is manufactured, the hollow rib 26 is formed in the direction of the arrow shown in FIG. 4 (B). It is not necessary to form the through hole 26C when the upper part of the is elastically deformed and a liquid or gel-like endothermic material is poured through the formed gap.

(Action / effect)
In the underfloor structure 60 according to the second embodiment, the heat absorbing material 42 is provided in the hollow portion 26B of the hollow rib 26 so as to straddle the spaces 12 and 14 partitioned by the wall body 30. When the hollow rib 26 of the deck plate 22 is heated by a flame or hot air at the time of a fire, heat is transferred along the hollow rib 26 (heat conduction), but this heat is absorbed by the heat absorbing material 42. That is, the heat absorbing material 42 made of concrete absorbs heat from the hollow rib 26. Therefore, heat propagation between the spaces 12 and 14 partitioned by the wall body 30 can be suppressed. That is, it is possible to suppress the formation of a heat bridge across the spaces 12 and 14.

Therefore, according to the underfloor structure 60 of the second embodiment, it is possible to suppress the spread of fire between the spaces 12 and 14 partitioned by the wall body 30.

In the present embodiment, the heat absorbing material 42 is filled only in the hollow portion 26B of the hollow rib 26, but the embodiment of the present invention is not limited to this. For example, in addition to the hollow portion 26B, a steel plate 44 is fixed to the lower surface of the hollow rib 26 as in the underfloor structure 10 according to the first embodiment shown in FIGS. The heat absorbing material 42 may be filled in the recess 26A (gap V in FIG. 4B) between the hollow ribs 26. As a result, the heat of the hollow rib 26 can be absorbed by the heat absorbing material 42 filled in both the hollow portion 26B and the recess 26A.

[Third Embodiment]
(Constitution)
5 (A) and 5 (B) show the underfloor structure 70 according to the third embodiment. In the underfloor structure 70, as in the first and second embodiments, the floor slab 20 in which concrete 28 is cast on the upper part of the deck plate 22 as a steel formwork and the wall provided below the floor slab 20. It has a body 30 and.

The flat portion 24 of the deck plate 22 is not formed with the through hole 24A (see FIGS. 2A and 2B) according to the first embodiment, and the lower surface of the hollow rib 26 is formed with the through hole 24A according to the second embodiment. Through holes 26C and 26D (see FIG. 4A) are not formed.

A heat shield plate 72 as an example of the fire heating suppression member in the present invention is fixed to the lower surface of the hollow rib 26, and the runner 32A constituting the wall body 30 is fixed to the hollow rib 26 with the heat shield plate 72 sandwiched between them. There is. Further, a gap V is formed between the heat shield plate 72 and the flat portion 24 of the deck plate 22.

(Action / effect)
In the underfloor structure 70 according to the third embodiment, a heat shield plate 72 straddling the spaces 12 and 14 partitioned by the wall body 30 is provided on the lower surface of the hollow rib 26. When the hollow rib 26 of the deck plate 22 is heated by the flame or hot air at the time of fire, the heat is transferred along the hollow rib 26, but this heat is released to the spaces 12 and 14 due to the presence of the heat shield plate 72. Is suppressed. Therefore, heat propagation between the spaces 12 and 14 partitioned by the wall body 30 can be suppressed.

Further, the flame or hot air at the time of fire may pass through the gap V formed between the heat shielding plate 72 and the flat portion 24 of the deck plate 22, and the flame or hot air is shielded by the heat shielding plate 72. Therefore, the release to the space side is suppressed. Therefore, it is possible to suppress the propagation of flames and hot air between the spaces 12 and 14.

Therefore, according to the underfloor structure 70 of the third embodiment, it is possible to suppress the spread of fire between the spaces 12 and 14 partitioned by the wall body 30.

Although the heat shield plate 72 is formed of a calcium silicate plate in the present embodiment, it may be formed of a non-combustible material such as an ALC plate or a material having high heat insulating properties.

Further, in the present embodiment, the heat shield plate 72 is continuously arranged from the space 12 to the space 14 at the upper part of the wall body 30, but the embodiment of the present invention is not limited to this. For example, like the heat shield plate 74 shown in FIG. 5C, it may be composed of two plates arranged on the space 12 side and the space 14 side, respectively, and each end surface 74A may be brought into contact with the side surface of the wall body 30. Good. That is, in the present invention, the state in which the fire heating suppression member "straddles the spaces on both sides partitioned by the fire protection partition wall" means that the fire heating suppression member is in contact with the wall body 30 on both sides partitioned by the wall body 30. It is assumed that the state of being installed in each of the spaces 12 and 14 of the above is included. By configuring the heat shield plate in this way, the wall body 30 can be easily fixed to the hollow rib 26.

Further, in the present embodiment, the heat absorbing material 42 (see FIGS. 2 (A), (B), 4 (A), (B)) is provided in the recess 26A between the hollow ribs 26 and the hollow portion 26B in the hollow ribs 26. Although not provided, the embodiments of the present invention are not limited to this. For example, in addition to the heat shielding plate 72, these heat absorbing materials 42 may be provided. By providing the endothermic material 42, the effect of suppressing the spread of fire between the spaces 12 and 14 partitioned by the wall body 30 can be further enhanced.

As described above, the embodiment of the present invention is not limited to one embodiment, and various embodiments can be combined and implemented.

10, 60, 70 Underfloor structure 20 Floor slabs 22, 52, 54, 56 Deck plates (steel formwork)
30 wall body (fireproof compartment wall)
42 Endothermic material (fire heating suppression member)
72 Heat shield plate (fire heating suppression member)

Claims (5)

Floor slabs with concrete placed in steel formwork,
A fire protection compartment wall provided below the floor slab and
A fire heating suppression member provided in contact with the steel formwork while straddling the spaces on both sides partitioned by the fire protection partition wall.
Have,
The steel formwork is a deck plate in which convex portions and concave portions are repeatedly formed.
The fire protection compartment wall is arranged along a direction in which the convex portion and the concave portion repeat.
Underfloor structure. Before Symbol fire heating suppressing member is a heat absorbing member provided on the recessed opened downwardly of the steel mold, underfloor structure according to claim 1. The underfloor structure according to claim 1, wherein the fire heating suppression member is a heat shield plate provided in contact with the lower surface of the steel formwork. The underfloor structure according to any one of claims 1 to 3, wherein the steel formwork is continuously arranged in front of and behind the fireproof partition wall. The underfloor structure according to any one of claims 1 to 4, wherein the fire heating suppression member is provided at a position separated from the surface of the fire compartment wall by a thickness equal to or greater than the thickness of the fire compartment wall.

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