JP7438764B2 - Fireproof structure of beams and its construction method - Google Patents

Description

The present invention relates to a fireproof structure of a beam and a construction method thereof.

In the floors of a building, on the indoor side of the exterior wall, beams made of steel sections such as H-beams are installed so as to extend in the width direction of the exterior wall, and the exterior walls are formed with respect to these beams. Exterior wall panels are installed.

Various fireproof measures have been taken for the beams made of shaped steel materials arranged on the indoor side of the exterior walls mentioned above. For example, measures such as installing fireproof plates to surround the beams, or rectangular fireproof plates with fireproof performance in the space formed by the upper and lower flanges and webs of beams made of H-beams. An example of this is measures to fit the two.

However, the measure of arranging fireproof plates so as to surround the beams takes time and effort because the fireproof plates are arranged around the beams. In particular, when fire-resistance measures are applied to beams with external walls placed on the sides as described above, the gaps between the beams and the external walls are narrow, making construction difficult and labor-intensive. This becomes even more obvious.

On the other hand, according to a measure to fit a rectangular fireproof plate having fire resistance performance into the space formed by the upper and lower flanges and webs of the H-shaped steel, the fireproof plate is fitted so as to close the space. Construction efficiency can be good because it only requires a lot of effort. However, for example, it is not possible to cover the outdoor end (face) of a flange of an H-shaped steel, and the exposed face ends lead to a decrease in fire resistance.

Therefore, a fire-resistant member that can be easily attached to and removed from a beam formed of a shaped steel material and that can improve fire-resistant performance, and a beam that includes this fire-resistant member have been proposed. Specifically, it is a fire-resistant member that is attached to a beam made of H-shaped steel, and this fire-resistant member has a beam insertion part that is inserted into the beam space, which is a space formed by upper and lower flanges and a web, and a fire-resistant performance. The beam insertion portion and the covering portion are formed integrally with the beam insertion portion. The end of the covering part extends so as to protrude beyond the beam insertion part in the direction spanning between the upper and lower flanges, and the covering part extends from the edge of the flange when the beam insertion part is inserted into the beam space (For example, see Patent Document 1).

Japanese Patent Application Publication No. 2017-66679

According to the fireproof member described in Patent Document 1, the space formed between the upper and lower flanges of the beam and the end face of the flange of the beam can be covered with fireproof at the same time, so that the fireproof performance of the beam can be improved. By the way, the fireproof member described in Patent Document 1 is fitted from the side of the beam so as to close the space formed between the upper and lower flanges, so it is not efficient when an external wall is not constructed on the side of the beam. Installation can be done on. On the other hand, when an external wall is constructed on the side of a beam, the space between the external wall and the beam is generally narrow, so it may take time and effort to install the fireproof member from the side of the beam.

The present invention has been made in view of the above problems, and is applicable to cases where an external wall is constructed on the side of a beam prior to the installation of fireproof boards (fireproof members), and cases where a fireproof board is installed prior to construction of the external wall. The purpose of the present invention is to provide a fire-resistant structure for beams and a method for constructing the same, which allows fire-resistant boards to be efficiently attached to beams in any case, and which has excellent fire-resistant performance.

In order to achieve the above object, one aspect of the fireproof structure of the beam according to the present invention is as follows:
A beam is provided on the indoor side of an exterior wall composed of a plurality of exterior wall panels, and extends in the width direction of the exterior wall with a gap between the beam and the exterior wall.
On the outdoor side of the beam, a metal fitting to be attached is attached to the beam directly or indirectly,
A fireproof board is attached to the attached metal fitting, and the fireproof board is arranged on the outdoor side of the beam,
The beam is formed of an H-beam with a web connecting an upper flange and a lower flange,
The fireproof board is arranged to extend from the upper flange to a position below the lower flange, and surrounds the outdoor side faces of both flanges.

According to this aspect, on the outdoor side of the beam, the fireproof board is attached to the attached metal fittings that are directly or indirectly attached to the beam, so that the outer wall is constructed on the side of the beam. It is possible to provide a fire-resistant structure for beams that enables efficient attachment of fire-resistant boards to beams, both when the external walls are installed and when the external walls are not constructed. In addition, a fireproof board is installed across the upper flange of the beam made of H-shaped steel to a position below the lower flange, making the outdoor side faces of both flanges fireproof. It is possible to form a fireproof structure of the beam that is completely surrounded by the board and has excellent fireproof performance against flames etc. from outside the fireproof board.

In particular, because the fireproof board is placed below the lower flange of the beam, even if the beam loses its strength and bends downward during a fire, the lower flange of the beam will still remain intact. The edges can be surrounded by a fireproof board. This prevents the beam from being exposed to flames and maintains the fire resistance of the beam. In addition, to determine the length from the lower flange of the beam to the lower end of the fireproof board, that is, to what extent the lower end of the fireproof board should be positioned below the lower flange of the beam, for example, conduct a fire resistance test. Determine the amount of deflection at the center position (the position where the amount of downward deflection is greatest) of a beam with predetermined specifications (for example, H-250 x 125 x 6 x 9, etc.) spanned over the Preferably, a fireproof board is applied with dimensions such that the lower end of the fireproof board is located in the lower position.

Here, "the attached metal fitting is directly or indirectly attached to the beam" refers to the form in which the attached metal fitting is directly attached to the beam by welding, etc., and the form in which the attached metal fitting is directly attached to the beam by welding, etc. The meaning includes a form in which the metal fitting to be attached is indirectly attached to the beam by joining the metal fitting to the steel material or the like by welding or the like. Furthermore, the fireproof board can be attached to the metal fittings to be installed, such as the one in which the fireproof board is directly fastened to the metal fittings with fixing means such as screws, or the one in which the fireproof board is engaged with the metal fittings to be installed. There are various forms such as.

Further, in another aspect of the fireproof structure of a beam according to the present invention, the attached metal fitting is an engaged metal fitting,
An engaging metal fitting is attached to the fireproof board, and the engaging metal fitting is engaged with the engaged metal fitting.

According to this aspect, by having a configuration in which the engaging metal fitting attached to the fireproof board is engaged with the engaged metal fitting, and the fireproof board is arranged on the outdoor side of the beam. Even if the gap between the beam and the outer wall is narrow, the engaging metal fitting can be vertically engaged (hook) with the engaged metal fitting. Therefore, it is possible to provide a fireproof structure for a beam that enables efficient attachment of a fireproof board to a beam, both when an external wall is constructed on the side of the beam and when no external wall is constructed.

Further, in another aspect of the beam fireproof structure according to the present invention, the beam is located between floors,
A plurality of gusset plates are attached to the beam and extend outward at predetermined intervals in the width direction,
The engaged metal fitting is attached to the wide side of the gusset plate facing in the width direction, and an upper fixing fitting and a lower fixing fitting are attached to the upper end and the lower end of the gusset plate, respectively,
The exterior wall panel of the upper floor is fixed to the upper fixing metal fitting, and the outer wall panel of the lower floor is fixed to the lower fixing metal fitting.

According to this aspect, a plurality of gusset plates are attached to the beam in its longitudinal direction (width direction of the outer wall), an engaged metal fitting is attached to each gusset plate, and upper fixing fittings are attached to the upper and lower ends of each gusset plate. Lower fixing brackets are installed, and the upper and lower floor exterior wall panels are fixed to these, providing a beam fireproof structure with excellent fire resistance and where the exterior wall panels are firmly fixed to the beams. can. Here, the engaged metal fittings are attached to the two wide sides of the gusset plate, and the engaging metal fittings are attached to both ends of the fireproof board, which has a length spanning the two gusset plates. By engaging the fireproof board with the two gusset plates, the fireproof board can be stably attached to the beam via the two gusset plates.

Further, in another aspect of the fireproof structure of a beam according to the present invention, an upper overhanging metal fitting and a lower overhanging metal fitting are attached to the upper and lower sides of the wide surface of the gusset plate, respectively, an upper nut is attached to the upper overhanging metal fitting, and an upper nut is attached to the upper overhanging metal fitting, and the lower The lower nut is attached to the overhanging metal fitting,
Both the upper fixing metal fitting and the lower fixing metal fitting have bolt holes,
The bolt hole of the upper fixing fitting is positioned with respect to the upper nut, and a bolt is inserted and bolted to fix the upper floor outer wall panel,
The outer wall panel of the lower floor is fixed by positioning the bolt hole of the lower fixing fitting with respect to the lower nut, and bolting the bolt through the bolt.

According to this aspect, the upper overhanging metal fitting having the upper nut and the lower overhanging metal fitting having the lower nut are attached to the gusset plate, and the upper fixing metal fitting and the lower fixing metal fitting are bolted to the upper nut and the lower nut, respectively. Accordingly, the external wall panel can be efficiently attached to the beam, and a fireproof structure of the beam can be provided in which the external wall panel is firmly fixed to the beam. The upper fixing bracket and the lower fixing bracket are made of shaped steel such as angle iron, and by applying the long upper fixing bracket and lower fixing bracket that extend in the longitudinal direction of the beam, it is possible to attach multiple external wall panels to these. Can be installed efficiently.

In another aspect of the fireproof structure of a beam according to the present invention, the fireproof board has a rectangular shape in side view and includes a pair of wide surfaces, a pair of vertical edges, and a pair of horizontal edges. ,
It is characterized in that at least the vertical edge is covered with a thermally expandable fireproof sheet.

According to this aspect, as the strength of the beams decreases due to heat during a fire, the beams bend in a curved manner in such a manner that the center position of the span between columns is located at the lowest position, and initially abut each other. When a gap was created between the vertical edges of adjacent fireproof boards that were attached to the beams in this way, the thermally expandable fireproof sheet covering at least the vertical edges of the fireproof boards thermally expanded. By doing so, it is possible to prevent the occurrence of gaps. As a result, a gap is created between the vertical edges of adjacent fireproof boards, and the metal fittings to be installed are exposed to fire through this gap. This prevents heat from being transferred to the beam through the exposed metal fittings. I can do it. Here, "thermal expansion" means an increase in volume due to heat, and includes thermal foaming of a fireproof sheet made of a heat-foamable resin.

In addition, "at least the vertical edges are covered with a thermally expandable fireproof sheet" refers to a form in which a fireproof sheet is disposed only on two vertical edges of a fireproof board that is rectangular in plan view. A fireproof sheet is placed from the vertical edge to a part of the wide side, and a fireproof sheet is placed on the two horizontal edges in addition to the two vertical edges (in other words, all of the fireproof board This includes a form in which a fireproof sheet is disposed at the edge, and a form in which a fireproof sheet is disposed from both the vertical edge and the horizontal edge over a part of the wide surface.

Further, in another aspect of the fireproof structure of a beam according to the present invention, the outer wall panel includes an exterior material, a panel frame disposed on the indoor side of the exterior material, and a panel frame disposed inside the panel frame. comprising at least an insulating material,
An in-wall fireproof board is disposed inside the heat insulating material and faces the beam.

According to this aspect, since the exterior wall panel has the in-wall fireproof board facing the beam, the fireproof board placed on the side of the beam and the in-wall fireproof board in the exterior wall panel with a gap in between. By arranging the beams so as to face each other, it is possible to form a fireproof structure of the beam with even better fireproof performance.

Another aspect of the fireproof structure of the beam according to the present invention is characterized in that a fireproof covering material is attached around the indoor side of the beam.

According to this aspect, since the fireproof board is attached to the outdoor side of the beam and the fireproof covering material is attached to the indoor side of the beam, the beam is surrounded by the fireproof board and the fireproof coating material, thereby making it even more effective. A fire-resistant beam structure with excellent fire-resistant performance can be formed.

Further, in another aspect of the fireproof structure of the beam according to the present invention, an ALC floor panel extending indoors is placed on the upper surface of the beam, and a closing material is provided in the gap between the outer wall panel and the ALC floor panel. It is characterized by being arranged.

According to this aspect, since the ALC (autoclaved light weight concrete) floor panel of the upper floor is arranged on the beam, the beam is completely covered with the fireproof board, fireproof covering material, and ALC floor panel. By being surrounded by the beam, it is possible to form a fireproof structure of the beam with even better fireproof performance. In addition, by filling the gap between the outer wall panel and the ALC floor panel with the closing material, a fireproof structure of the beam with even better fireproof performance can be formed.

Further, one aspect of the construction method for the fireproof structure of a beam according to the present invention is as follows:
On the outdoor side of the beam formed of H-beam steel, where the web connects the upper flange and the lower flange, the mounting bracket is attached directly or indirectly to the beam, and the outdoor side of the beam is attached directly or indirectly to the beam. an exterior wall construction step of constructing an exterior wall composed of a plurality of exterior wall panels with a gap between the beam and the beam;
A fire-resistant board installation in which the fire-resistant board is installed on the outdoor side of the beam by inserting the fire-resistant board into the gap from above or below the beam and attaching the fire-resistant board to the attached metal fitting. having a process;
In the fireproof board installation step, the fireproof board is arranged from the upper flange to a position below the lower flange, and surrounds the outdoor side edges of both flanges. shall be.

According to this aspect, prior to the installation of the fireproof board, after the exterior wall is constructed on the outdoor side of the beam in the exterior wall construction process, the fireproof board is installed in the gap between the beam and the exterior wall in the fireproof board installation process. Regardless of the construction method, the fireproof board can be efficiently attached to the beam by attaching the fireproof board to the metal fittings of the beam. In addition, in the fireproof board installation process, the fireproof board is placed from the upper flange of the beam to a position below the lower flange, and is installed so as to surround the outdoor side edges of both flanges. As a result, even if the beam loses its strength and bends downward in the event of a fire, the face of the lower flange of the beam can still be surrounded by the fireproof board, preventing the beam from being exposed to flames, etc. is prevented, and the fire resistance performance of the beam can be maintained.

In addition, if the beam is between floors and the exterior wall is formed by the exterior wall on the lower floor and the exterior wall on the upper floor, the exterior wall construction process involves constructing both the exterior wall on the lower floor and the exterior wall on the upper floor. This includes constructing the exterior walls on the lower floor and the exterior walls on the upper floor. In the latter case, an exterior wall construction process in which the exterior walls on the lower floor are constructed first, a fireproof board installation process, and an exterior wall construction process in which the exterior walls on the upper floor are constructed are sequentially executed. Also in this embodiment, the fireproof board is preferably covered with a thermally expandable fireproof sheet at least from the vertical edge to a part of the wide side.

Also in this aspect, it is preferable that the attached metal fitting is an engaged metal fitting, that the engaging metal fitting is attached to the fireproof board, and that the engaging metal fitting is engaged with the engaged metal fitting. Even if the gap between the beam and the exterior wall is narrow, if the exterior wall is constructed on the side of the beam by vertically engaging (hanging) the engaging metal fittings with the engaged metal fittings. In this way, even more efficient attachment of the fireproof board to the beam is possible.

Further, other aspects of the method for constructing a fireproof structure for beams according to the present invention include:
By attaching a fireproof board to the attached metal fittings that are directly or indirectly attached to the beam on the outdoor side of the beam formed by H-shaped steel whose web connects the upper flange and the lower flange, a fireproof board installation step of installing the fireproof board on the outdoor side of the beam;
an exterior wall construction step of constructing an exterior wall composed of a plurality of exterior wall panels with a gap between the beam and the fireproof board;
In the fireproof board installation step, the fireproof board is arranged from the upper flange to a position below the lower flange, and surrounds the outdoor side edges of both flanges. shall be.

According to this aspect, by using the construction method in which the fireproof board installation process is performed prior to the exterior wall construction process, a relatively large construction space is secured on the outdoor side of the beam, where no exterior wall is constructed on the outdoor side of the beam. Since the fireproof board can be attached in the state where the fireproof board is attached to the beam, the fireproof board can be attached to the beam even more efficiently.

As can be understood from the above explanation, according to the fireproof structure of the beam and its construction method of the present invention, there are two cases in which an external wall is constructed on the side of the beam prior to the installation of the fireproof board, and a case in which the external wall is constructed on the side of the beam prior to the installation of the fireproof board. To provide a fire-resistant structure for beams and a method for constructing the same, which enables fire-resistant boards to be efficiently attached to beams and has excellent fire-resistant performance in any case where fire-resistant boards are installed. I can do it.

FIG. 2 is a diagram showing a beam forming the fireproof structure of the beam and a gusset plate attached to the beam according to the embodiment, and is a longitudinal cross-sectional view orthogonal to the longitudinal direction of the beam. FIG. 2 is a view taken along the line II-II in FIG. 1, and is a side view of the beam seen from the back side of the engaged metal tool, and also shows the beam whose strength has decreased and is bent downward. FIG. 2 is a side view of the beam seen from the back side of the upper projecting metal fitting and the lower projecting metal fitting, taken along the line III-III in FIG. 1; (a) is a side view of the fireproof board viewed from the wide side to which the engaging metal fittings are attached, and (b) is a view taken in the direction of arrow b in (a). It is a longitudinal cross-sectional view showing an example of the fireproof structure of the beam concerning an embodiment. It is a process chart showing an example of the construction method of the fireproof structure of the beam concerning an embodiment. Following FIG. 6, it is a process diagram showing an example of a construction method for a fireproof structure of a beam. Continuing from FIG. 7, it is a process diagram showing an example of a construction method for a fireproof structure of a beam.

Hereinafter, an example of the fireproof structure of a beam and its construction method according to an embodiment will be described with reference to the attached drawings. Note that in this specification and the drawings, substantially the same constituent elements may be given the same reference numerals to omit redundant explanation.

[Fireproof structure of beam according to embodiment]
First, an example of a fireproof structure of a beam according to an embodiment will be described with reference to FIGS. 1 to 5. Here, FIG. 1 is a diagram showing a beam forming a fireproof structure of the beam and a gusset plate attached to the beam according to an embodiment, and is a longitudinal cross-sectional view orthogonal to the longitudinal direction of the beam. 2 is a view taken along the line II-II in FIG. 1, and is a side view of the beam seen from the back side of the engaged metal tool. FIG. 3 is a view taken along the line III-III in FIG. FIG. 2 is a side view of the beam seen from the back side of the upper and lower projecting metal fittings. Further, FIG. 4(a) is a side view of the fireproof board viewed from the wide side to which the engaging metal fittings are attached, and FIG. 4(b) is a view taken in the direction of arrow b in FIG. 4(a). . Furthermore, FIG. 5 is a longitudinal cross-sectional view showing an example of the fireproof structure of the beam according to the embodiment. The illustrated example is an example in which a gusset plate is attached to an H-shaped steel forming a beam, and an engaging metal fitting attached to a fireproof board engages with an engaged metal fitting attached to the gusset plate. Although shown, other forms may be used, such as a form in which the fireproof board engages with an engaged metal fitting attached to the H-section steel by direct welding or the like.

The beam 10 shown in FIG. 1 is a beam arranged on the side of the outer wall between floors such as between the first and second floors, between the second and third floors, and has an upper flange 11, a lower flange 12, It is formed of H-beam steel having a web 13 connecting these parts. Here, H-section steel with various specifications is applied to the beam 10 depending on the installation location, such as H-250 x 125 x 6 x 9 or H-400 x 200 x 8 x 13, etc. The beam 10 shown in FIG. 1 etc. is illustrated as H-250×125×6×9.

A gusset plate 20 is attached to the outdoor space formed by the upper flange 11, lower flange 12, and web 13 of the beam 10, and as shown in FIG. A plurality of gusset plates 20 are attached at intervals t1 corresponding to the width of the outer wall panel 30 shown in FIG. 4 in the L direction, which is the longitudinal direction of the beam 10. For example, this interval t1 can be set to 1P or 2P when the width of the outer wall panel 30 is 1P (1P is about 800 mm to 1000 mm, for example, 910 mm).

As shown in FIG. 1, the gusset plate 20 is housed in a space formed by the upper flange 11, the lower flange 12, and the web 13, and includes a joining plate 21 that is welded to these parts. It has an overhanging plate 22 that continues upward and overhangs outdoors, and is formed of a flat steel plate.

As shown in FIGS. 1 and 2, on the left and right wide sides of the gusset plate 20, two engaged metal fittings 24 (covered metal fittings 24) formed of angle iron are located near the connection plate 21 with the overhanging plate 22. (Example of mounting hardware) are joined by welding.

In addition, as shown in FIGS. 1 and 3, two upwardly extending metal fittings 25 made of angle iron are provided at the upper end of the overhanging plate 22 among the wide left and right sides of the gusset plate 20. They are joined by welding in a position facing toward the A bolt hole 25a is formed in the upper projecting metal fitting 25, and an upper nut 26 is welded to the lower surface of the upper projecting metal fitting 25 at a position corresponding to the bolt hole 25a.

Similarly, as shown in FIGS. 1 and 3, two downwardly projecting metal fittings 27 made of angle iron are provided at the lower end of the projecting plate 22 among the left and right wide surfaces of the gusset plate 20. They are joined by welding in an upward and downward direction. A bolt hole 27a is formed in the downwardly projecting metal fitting 27, and a lower nut 28 is welded to the upper surface of the downwardly projecting metal fitting 27 at a position corresponding to the bolt hole 27a.

As shown in FIGS. 4(a) and 4(b), the fireproof board 30 is formed of a rock wool board, a gypsum board, etc. that is rectangular in plan view (for example, 903 x 400 x 21 mm (thickness)). Reinforced gypsum board, which has a gypsum core with glass fiber added to enhance fire resistance, is preferred.

Two engaging fittings 35 are fixed to the wide side 31 on the indoor side of the fireproof board 30 near the left and right narrow end faces 32 (a pair of vertical edges 32a) by fixing means such as screws 40. The engaging fitting 35 is formed by bending a flat steel material, and includes a fixed piece 35a into which the screw 40 is driven, a wrap-around piece 35b that bends from the edge of the fixed piece 35a and wraps around toward the indoor side, and an end of the wrap-around piece 35b. It has an engaging piece 35c that is bent from the side and directly engages the engaged metal fitting 24.

In addition, two gripping fittings 38 are provided near the left and right narrow end surfaces 32 (vertical edges 32a) of the lower end (lower horizontal edge 32b) of the outdoor wide side 31 of the fireproof board 30, such as screws 40, etc. It is fixed by a fixing means. The gripping fitting 38 may be provided at an appropriate position on the outdoor wide side of the fireproof board 30 so that a worker can easily grip and handle the fireproof board 30. Incidentally, in the installation work of the fireproof board 30, if there is no need to grip the gripping metal fittings 38, the gripping metal fittings 38 can be omitted.

Moreover, a pair of left and right vertical edges 32 a of the fireproof board 30 are covered with a thermally expandable fireproof sheet 33 . More specifically, a thermally expandable fireproof sheet 33 covers a part of the wide surface 31 from the vertical edge 32a. On the other hand, the pair of upper and lower side edges 32b of the fireproof board 30 are also covered with a thermally expandable fireproof sheet 34 extending from the side edges 32b to part of the wide surface 31.

The fireproof sheets 33 and 34 have a thickness of, for example, about 2 mm, and are made of a thermally foamable resin sheet that expands to about 10 times its volume when thermally expanded. The fireproof board 30 shown in FIG. 4 is engaged with the engaged metal fittings 24 on the inside of the left and right gusset plates 20 shown in FIG. It is engaged with the outer metal fitting 24 and the metal fitting 24 of the gusset plate 20 (not shown). At this time, the adjacent fireproof boards 30 are installed with their vertical edges 32a in contact with each other without any gaps.

By the way, the strength of the beam 10 decreases due to the heat caused by the fire, and the beam 10 is arranged in such a manner that the center position of the span between columns (not shown) is located at the lowest position, as shown by the dashed line in FIG. Deflects in a curved shape (maximum deflection amount δ). The left and right fireproof boards 30, which were attached to the beam 10 with their respective vertical edges 32a in contact with each other, are displaced in accordance with the deflection of the beam 10, and a gap may occur between the respective vertical edges 32a. However, due to the thermal expansion of the thermally expandable fireproof sheet 33 that covers a part of the wide side 31 from the vertical edge 32a of the fireproof board 30, it is difficult to prevent the generation of gaps between the fireproof boards 30. can. Therefore, a gap is created between the vertical edges 32a of adjacent fireproof boards 30, the engaged metal fittings 24 are exposed to fire through this gap, and heat is transmitted to the beam 10 via the exposed engaged metal fittings 24. It can prevent it from getting heated.

The fireproof board 30 in the illustrated example has a configuration in which both the vertical edge 32a and the horizontal edge 32b are covered with fireproof sheets 33 and 34 over a part of the wide surface 31, but only the vertical edge 32a is covered with fireproof sheets 33 and 34. may be covered with a fireproof sheet (the fireproof sheet does not extend to the wide side 31), or only the vertical edges 32a and the horizontal edges 32b may be covered with a fireproof sheet (the vertical edges 32a The fireproof sheet covering both the side edge 32b and the side edge 32b may not extend to the wide side 31).

In FIG. 5, the beam 10 is located on the side of the indoor side of the outer wall 70, and the engaging metal fitting 35 of the fireproof board 30 is attached to the engaging metal fitting 24 of the gusset plate 20 attached to the beam 10. 1 shows a fireproof structure 100 of beams formed by engagement.

There is a narrow gap G between the beam 10 and the outer wall 70, and on the outdoor side of the beam 10 (inside the gap G), when the engaging metal fitting 35 engages with the engaged metal fitting 24, A fireproof board 30 is attached. More specifically, the fireproof board 30 is installed on the side of the beam 10 and extends from the outdoor side face of the upper flange 11 to the outdoor side face of the lower flange 12, and It is installed in such a way that it completely blocks the small end surface of the

More specifically, the fireproof board 30 is disposed across from the upper flange 11 to a position below the lower flange 12 (a position below the lower flange 12 by length t2).

Since the fireproof board 30 is disposed at a position lower than the lower flange 12 of the beam 10, even if the beam 10 loses its strength and bends downward as shown in FIG. 2 in the event of a fire, Even if there is, the face of the flange 12 below the beam 10 can still be surrounded by the fireproof board 30. This prevents the beam 10 from being exposed to flames, etc., and maintains the fire resistance performance of the beam 10.

Here, in setting the length t2 from the lower flange 12 of the beam 10 to the lower end of the fireproof board 30, for example, a fire resistance test is performed to determine the maximum deflection amount δ (see FIG. 2) of the beam 10 with predetermined specifications. It is preferable to set the length to be equal to or greater than this maximum deflection amount δ. The length t2 can be set, for example, within a range of about 10 mm to 100 mm.

The beam 10 is arranged between floors, and the outer wall 70 on the outdoor side of the beam 10 with a gap G in between is formed by an outer wall 70B on the lower floor and an outer wall 70A on the upper floor, and each outer wall 70A, 70B Both are formed by a plurality of exterior wall panels.

The exterior wall panel 70 is constructed by laminating an exterior material 71, an underlay material 72, and a panel frame 73 in order from the outdoor side, and the inside of the panel frame 73 is filled with a heat insulating material 74.

The exterior material 71 is formed of, for example, a ceramic or metal siding board. Further, the underlay material 72 is formed of glass wool board or the like. An exterior base material (not shown) made of hard wood cement board or the like is interposed between the exterior material 71 and the underlay material 72. A ventilation layer 75 is formed. The panel frame 73 is formed by assembling light iron channel steel into a frame shape. Further, the heat insulating material 74 is made of glass wool, rock wool, or the like. Although not shown, an interior material made of a moisture-proof sheet, gypsum board, etc. is attached to the indoor side of the outer wall panel 70.

Furthermore, inside the heat insulating material 74 of the upper floor exterior wall panel 70A, an in-wall fireproof board 78 formed of rock wool board, gypsum board, etc. is disposed at a position facing the fireproof board 30, and is attached to the beam 10. It's coming. Here, from the viewpoint of fireproof performance around the beam 10, it is preferable that both the fireproof board 30 and the in-wall fireproof board 78 be formed of reinforced gypsum board. In the illustrated example, an in-wall fireproof board 78 is embedded only inside the heat insulating material 74 of the outer wall panel 70A on the upper floor, but in addition, an in-wall fireproof board 78 is embedded inside the heat insulating material 74 on the outer wall panel 70B on the lower floor. It may also be a form in which a fireproof board is embedded within the wall.

An upper fixing bracket 50 extending in the longitudinal direction of the beam and formed of angle iron is placed on the upper surface of the upper projecting bracket 25 attached to the upper ends of the plurality of gusset plates 20 shown in FIG. In the upper fixing fitting 50 in the placed state, bolt holes 51 are opened at positions corresponding to the bolt holes 25a of the respective upper projecting fittings 25. By screwing bolts 60 (double-cut bolts) into the corresponding upper nuts 26 and bolt holes 25a and 51, the upper fixing metal fittings 50 are bolted across the upper ends of the plurality of gusset plates 20.

Similarly, a lower fixing bracket 55 extending in the longitudinal direction of the beam and formed of angle iron is in contact with the lower surface of the lower projecting bracket 27 attached to the lower ends of the plurality of gusset plates 20 shown in FIG. In the lower fixing metal fittings 55 in this abutted state, bolt holes 56 are opened at positions corresponding to the bolt holes 27a of the respective lower projecting metal fittings 27. By screwing bolts 60 (double-cut bolts) into the corresponding lower nuts 28 and bolt holes 27a and 56, the lower fixing metal fittings 55 are bolt-bonded across the lower ends of the plurality of gusset plates 20.

Of the upper fixing bracket 50 made of angle iron bolted to the upper surface of the upper projecting bracket 25, bolt holes 52 are opened at predetermined intervals in the longitudinal direction of the upper fixing bracket 50 in the upwardly rising flange. There is. On the other hand, bolt holes 73a are also formed in the panel frame 73 constituting the outer wall panel 70A on the upper floor at intervals in the width direction of the outer wall panel 70A, and bolts 65 ( By screwing together the hook bolts, the upper floor outer wall panel 70A is bolted to the upper fixing fitting 50.

Similarly, bolt holes 57 are formed at predetermined intervals in the longitudinal direction of the lower fixing bracket 55 in the downwardly downward flange of the lower fixing bracket 55 made of angle iron bolted to the lower surface of the lower projecting bracket 27. It has been established. On the other hand, bolt holes 73a are also formed in the panel frame 73 constituting the outer wall panel 70B on the lower floor at intervals in the width direction of the outer wall panel 70B, and bolts 65 ( By screwing together the hook bolts, the outer wall panel 70B on the lower floor is bolted to the lower fixing fitting 55.

A horizontal joint is formed at the interface between the upper floor exterior wall panel 70A and the lower floor exterior wall panel 70B, which are bolted to the upper fixing bracket 50 and the lower fixture 55, respectively, and a dry or wet seal is applied to this horizontal joint. By disposing the material 76, the upper floor outer wall panel 70A and the lower floor outer wall panel 70B between floors are constructed.

A plurality of weld pins 85 are joined to the indoor side face of the upper flange 11 and the lower surface of the lower flange 12 of the beam 10 . Then, the first layer is applied from the indoor side edge surface of the upper flange 11 of the beam 10 to the indoor side edge surface of the lower flange 12, and further from the lower surface of the lower flange 12 to the position where it abuts the fireproof board 30. A fireproof coating 81 is provided and fixed to a plurality of weld pins 85. Furthermore, a second layer of fireproof coating 82 extends on the indoor side of the first layer of fireproof coating 81 so as to surround the first layer of fireproof coating 81, and the end of the fireproof coating 82 is attached to the wall. It is fixed to the side surface of the panel 70B with screws 40. Here, the fire-resistant covering material 80 is formed, for example, from a laminate of heat-resistant rock wool shaped into a felt shape and a flame-retardant nonwoven fabric. Although not shown, a single layer of fireproof coating material extends from the indoor side face of the upper flange 11 of the beam 10 to the indoor side face of the lower flange 12, and further extends from the lower face of the lower flange 12. It may extend over the side surface of the wall panel 70B via the fireproof board 30.

An ALC floor panel 90 extending toward the indoor side is placed on the upper surface of the upper flange 11 forming the beam 10, and a closing material 95 is provided in the gap between the outer wall panel 70 and the ALC floor panel 90. ing.

Here, as the closing material 95, rock wool or glass wool is applied. Since these materials are fiber-based heat insulating materials and have heat insulation and heat shielding properties, the gap between the outer wall panel 70 and the ALC floor panel 90 can be completely closed to improve the fire resistance performance of the fireproof structure 100 of the beam. Contribute to Furthermore, for example, sound energy incident on glass wool insulation propagates inside the glass wool, vibrates the glass fibers and air, and is converted into thermal energy. It has sound absorption characteristics that cover a wide range of sounds.

According to the beam fireproof structure 100, the engagement fitting 35 attached to the fireproof board 30 is engaged with the engagement fitting 24 attached to the outdoor side of the beam 10, and the beam 10 Even if the gap G between the beam 10 and the outer wall 70 is narrow, the fireproof board 30 is disposed on the side of the outdoor side, so that the engaged metal fittings 24 are not affected by the fireproof board 30. The tool 35 can be hung in the vertical direction. Therefore, the fireproof board 30 can be efficiently attached to the beam 10 both when the outer wall 70 is constructed on the side of the beam 10 and when the outer wall 70 is not constructed.

Further, an upper overhanging metal fitting 25 having an upper nut 26 and a lower overhanging metal fitting 27 having a lower nut 28 are attached to the gusset plate 20, and an upper fixing metal fitting 50 and a lower fixing metal fitting 55 are attached to the upper nut 26 and the lower nut 28, respectively. are bolted together, and the outer wall panel 70 is bolted to the upper fixture 50 and the lower fixture 55, so that the exterior wall panel 70 can be efficiently and firmly attached to the beam 10.

In addition, a fireproof board 30 that is engaged with the beam 10 covers the outdoor side edges of the upper flange 11 and the lower flange 12 of the beam 10, and is further arranged to straddle a position below the lower flange 12. In addition, a fireproof covering material 80 is arranged so as to extend from the indoor side edge surface of the upper flange 11 of the beam 10 to the indoor side edge surface of the lower flange 12, and further to the lower surface of the lower flange 12. The fireproof beam structure 100 has excellent fireproof performance due to the fact that the fireproof board 30 is provided with at least the vertical edges 32a covered with the thermally expandable fireproof sheet 33. In the beam fireproof structure 100, an in-wall fireproof board 78 is disposed inside the heat insulating material 74 of the outer wall panel 70A at a position opposite to the fireproof board 30 and faces the beam 10. The fact that the ALC floor panel 90 is placed on the top surface of the flange 11 also contributes to excellent fire resistance performance.

In the fireproof structure 100 of the beam shown in the drawing, the engaging piece 35c of the engaging fitting 35 attached to the fireproof board 30 is engaged with the engaged fitting 24 attached to the gusset plate 20. For example, a bolt groove is provided at the upper end of the engaged metal fitting, and the bolt attached to the fireproof board 30 is fitted into the bolt groove from above and engaged. Good too. Alternatively, the fireproof board 30 may be directly fixed to the engaged metal fittings using fixing means such as screws.

[Construction method of fireproof structure of beam according to embodiment]
Next, an example of the method for constructing the fireproof structure of a beam according to the embodiment will be described with reference to FIGS. 6 to 8 and FIG. 5, which was already referred to in the description of the fireproof structure of a beam. Here, FIGS. 6 to 8 and then FIG. 5 are process charts of an example of a method for constructing a fireproof structure in that order.

First, as shown in FIG. 6, on the outdoor side of the beam 10 to which the gusset plate 20 extending toward the outdoor side is attached, an outer wall made up of a plurality of outer wall panels 70 with a gap G between the beam 10 and the beam 10. construction.

Here, the beam 10 is a beam located between floors, and an upwardly extending metal fitting with an upper nut 26 is attached at the upper and lower ends of a plurality of gusset plates 20 that are joined to the beam 10 at intervals in the longitudinal direction. A downward extending metal fitting 27 having a lower nut 25 and a lower nut 28 is attached.

Then, the upper fixing bracket 50 extending in the longitudinal direction of the beam 10 is placed on the upper overhanging bracket 25 and bolted to the upper nut 26, and the lower fixing bracket 55 extending in the longitudinal direction of the beam 10 is placed on the upper overhanging bracket 25. 27 and bolted to the lower nut 28.

The upper floor exterior wall is constructed by bolting the upper floor exterior wall panel 70A to the upper fixing bracket 50, and the lower floor exterior wall is constructed by bolting the lower floor exterior wall panel 70B to the lower fixture 55. (The above is the exterior wall construction process).

Next, as shown in FIG. 7, the fireproof board 30 to which the engaging metal fittings 35 are attached is inserted into the gap G from above the beam 10 in the X1 direction or from below the beam 10 in the X2 direction. At this time, the worker inserts the fireproof board 30 into the gap G while grasping the gripping fitting 38 at the lower end of the fireproof board 30.

After inserting the fireproof board 30 into the gap G, slide it in the X3 direction until the indoor wide side of the fireproof board 30 comes into contact with the outdoor side edges of both the upper flange 11 and the lower flange 12 of the beam 10. let Next, the engaging piece 35c of the engaging metal fitting 35 attached to the wide side of the fireproof board 30 is dropped downward in the X4 direction and engaged with the engaged metal fitting 24 attached to the gusset plate 20. As a result, the fireproof board 30 is installed on the outdoor side of the beam 10 (fireproof board installation step).

After the fireproof board 30 is installed on the outdoor side of the beam 10, as shown in FIG. After filling the space with a blocking material 95, a fireproof structure 100 of the beam is constructed by installing a fireproof covering material 80 on the indoor side of the beam 10, as shown in FIG.

Although the illustrated example is a construction method in which the fireproof board installation step is performed next to the exterior wall construction step, a construction method may be employed in which the fireproof board installation step is performed first and then the exterior wall construction step is performed.

In this way, regardless of the construction method, which is a method of constructing the outer wall 70 on the side of the beam 10 prior to the installation of the fireproof board 30, or a method of installing the fireproof board 30 prior to the construction of the outer wall 70, , by inserting the fireproof board 30 into the gap G on the side of the beam 10, dropping and engaging the engaging metal fitting 35 of the fireproof board 30 with the engaged metal fitting 24 of the beam 10, and attaching the fireproof board 30. , the fireproof board 30 can be efficiently attached to the beam 10.

It should be noted that other embodiments may be adopted in which other components are combined with the configurations listed in the above embodiments, and the present invention is not limited to the configurations shown here. In this regard, changes can be made without departing from the spirit of the present invention, and can be appropriately determined depending on the application form.

10: Beam (H-shaped steel)
11: Upper flange 12: Lower flange 13: Web 20: Gusset plate 21: Joint plate 22: Overhang plate 24: Engaged metal fitting (attached metal fitting)
25: Upper overhanging metal fitting 26: Upper nut 27: Lower overhanging metal fitting 28: Lower nut 30: Fireproof board 31: Wide side 32: Narrow width end face 32a: Vertical edge 32b: Horizontal edge 33, 34: Fireproof sheet 35: Engaging metal fittings 35c: Engagement piece 38: Grip fitting 40: Screw (fixing means)
50: Upper fixing bracket 51: Bolt hole 55: Lower fixing bracket 56: Bolt hole 60, 65: Bolt 70: External wall panel (outer wall)
70A: Upper floor exterior wall panel (exterior wall panel, exterior wall)
70B: Lower floor exterior wall panel (exterior wall panel, exterior wall)
71: Exterior material 72: Underlay material 73: Panel frame 74: Heat insulation material 81, 82: Fireproof covering material 85: Welding pin 90: ALC floor panel 95: Closure material 100: Fireproof structure of beam G: Gap

Claims (9)

A beam is provided on the indoor side of an exterior wall composed of a plurality of exterior wall panels, and extends in the width direction of the exterior wall with a gap between the beam and the exterior wall.
On the outdoor side of the beam, a metal fitting that is a metal fitting to be attached is attached directly or indirectly to the beam,
An engaging metal fitting is attached to the fireproof board, the engaging metal fitting is engaged with the engaged metal fitting , and the fireproof board is arranged on the outdoor side of the beam,
The beam is formed of an H-beam with a web connecting an upper flange and a lower flange,
The fireproof board is disposed from the upper flange to a position below the lower flange, and surrounds the outdoor side faces of both flanges. Fireproof construction. The beam is located between floors;
A plurality of gusset plates are attached to the beam and extend outward at predetermined intervals in the width direction,
The engaged metal fitting is attached to the wide side of the gusset plate facing in the width direction, and an upper fixing fitting and a lower fixing fitting are attached to the upper end and the lower end of the gusset plate, respectively,
2. The beam fireproof structure according to claim 1 , wherein an exterior wall panel on an upper floor is fixed to the upper fixing bracket, and an exterior wall panel on a lower floor is fixed to the lower fixing bracket. An upper overhanging metal fitting and a lower overhanging metal fitting are attached to the upper and lower sides of the wide surface of the gusset plate, respectively, an upper nut is attached to the upper overhanging metal fitting, and a lower nut is attached to the lower overhanging metal fitting,
Both the upper fixing metal fitting and the lower fixing metal fitting have bolt holes,
The bolt hole of the upper fixing fitting is positioned with respect to the upper nut, and a bolt is inserted and bolted to fix the upper floor outer wall panel,
3. The outer wall panel of the lower floor is fixed by positioning the bolt hole of the lower fixing fitting with respect to the lower nut, inserting a bolt, and bolt -joining the panel. Fireproof construction of the listed beams. The fireproof board has a rectangular shape in side view, and includes a pair of wide surfaces, a pair of vertical edges, and a pair of horizontal edges,
The fireproof structure of a beam according to any one of claims 1 to 3 , wherein at least the vertical edge is covered with a thermally expandable fireproof sheet. The exterior wall panel includes at least an exterior material, a panel frame disposed on the indoor side of the exterior material, and a heat insulating material disposed inside the panel frame,
The fireproof structure of a beam according to any one of claims 1 to 4 , characterized in that an in-wall fireproof board is disposed inside the heat insulating material and faces the beam. The fireproof structure of a beam according to any one of claims 1 to 5 , characterized in that a fireproof coating is attached around the interior side of the beam. An ALC floor panel extending indoors is placed on the upper surface of the beam, and a closing material is provided in a gap between the outer wall panel and the ALC floor panel. 6. The fireproof structure of the beam according to any one of Item 6 . On the outdoor side of the beam formed of H-beam steel, whose web connects the upper flange and the lower flange, the attached metal fittings, which are the attached metal fittings, are attached directly or indirectly to the beam. , an exterior wall construction step of constructing an exterior wall composed of a plurality of exterior wall panels on the outdoor side of the beam with a gap between the beam and the beam;
By inserting the fireproof board to which the engaging metal fitting is attached into the gap from above or below the beam and engaging the engaging metal fitting with the engaged metal fitting , the outdoor side of the beam is a fireproof board installation step of installing the fireproof board on the side;
In the fireproof board installation step, the fireproof board is arranged from the upper flange to a position below the lower flange, and surrounds the outdoor side edges of both flanges. A method of constructing a fire-resistant structure for beams. On the outdoor side of a beam formed of H-shaped steel whose web connects the upper flange and the lower flange, to the attached metal fitting that is directly or indirectly attached to the beam. a fire-resistant board installation step of installing the fire-resistant board on the outdoor side of the beam by engaging the engaging metal fittings of the fire -resistant board to which the engaging metal fittings are attached ;
an exterior wall construction step of constructing an exterior wall composed of a plurality of exterior wall panels with a gap between the beam and the fireproof board;
In the fireproof board installation step, the fireproof board is arranged from the upper flange to a position below the lower flange, and surrounds the outdoor side edges of both flanges. A method of constructing a fire-resistant structure for beams.

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