JP2018003556A - Fire-resisting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fire-resisting structure that reduces fire-resistive covering on a steel beam for sufficiently reducing a cost and curtailing a construction period, by appropriately evaluating an actual behavior of the steel beam exposed to fire heat input.SOLUTION: A fire-resisting structure 1 that applies the present invention is provided on a beam member of a building, and includes a plurality of column members 2, a plurality of girders 3 spanned on the column member 2, a beam 4 provided inside a space surrounded by the plurality of girders 3, and a floor slab 5 provided above the beam 4. The plurality of girders 3 includes a pair of orthogonal girders 31 provided roughly orthogonally to the beam 4, and a pair of parallel girders 32 provided roughly parallelly to the beam 4, and fire-resistive covering is applied on the first girder 3 of either the orthogonal girder 31 or the parallel girder 32. The fire-resistive covering applied on the second girder 3 of the orthogonal girder 31 or the parallel girder 32, as well as on the beam 4, is reduced more than the fire-resistive covering applied on the first girder 3 of either the orthogonal girder 31 or the parallel girder 32.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fireproof structure provided in a beam member of a building.

  Conventionally, the reinforcement disclosed in Patent Document 1 is intended to improve the slab performance and reliability as well as the workability by embedding and attaching the upper part of the reinforcing steel frame under the RC floor slab. RC floor slabs with steel frames have been proposed.

  An RC floor slab with a reinforcing steel frame disclosed in Patent Document 1 is an RC floor slab that is integrally incorporated in a column, a large beam, and the like. It is characterized by being embedded directly or indirectly with a fireproof coating.

JP 7-42293 A

  Here, in a steel structure building that requires fireproof performance, a method of preventing fire collapse by reducing fire heat input by applying fireproof coating to columns and beams is common. However, a shortage of fireproof coating workers has become apparent in Japan, and it is expected that a new fireproof structure with reduced fireproof coating will be put to practical use by appropriately evaluating the actual behavior of steel members subjected to fire heat input. Yes.

  In overseas, where non-earthquake resistant areas occupy Taejong, it is important to secure fireproof performance in the structural design of steel-framed structures, so it is possible to simultaneously reduce costs and shorten construction time by reducing the fireproof coating of steel beams. If it can be realized, the appeal of steel structure will be greatly improved.

  The RC floor slab with a reinforcing steel frame disclosed in Patent Document 1 embeds the upper part of the reinforcing steel frame under the RC floor slab, and the reinforcing steel frame to be a small beam is attached with a fireproof coating, It is possible to reduce the fireproof coating in the steel structure.

  However, the RC floor slab with reinforced steel disclosed in Patent Document 1 is premised on the use of RC large beams or fire-resistant S-shaped large beams, and the actual behavior of steel beams subjected to fire heat input is appropriate. It has not been evaluated. The RC floor slab with a reinforced steel frame disclosed in Patent Document 1 does not reduce the fire-resistant coating of the large beam using the RC beam or the S-shaped beam with fire-resistant coating. The shortening was insufficient.

  Therefore, the present invention has been devised in view of the above-described problems, and the object of the present invention is to appropriately evaluate the actual behavior of a steel beam subjected to fire heat input, The object is to provide a fireproof structure that is sufficient in cost reduction and construction period shortening due to the reduction of the cost.

  The fireproof structure according to the first invention is a fireproof structure provided in a beam member of a building, and includes a plurality of column members, a plurality of large beams installed on the column members, and an inner side surrounded by the plurality of large beams. A small beam provided, and a floor slab provided above the small beam, wherein the plurality of large beams are provided substantially perpendicular to the small beam, and a pair of orthogonal large beams and the small beam A pair of parallel large beams provided substantially in parallel, and a fireproof coating is applied to any one of the orthogonal large beams and the parallel large beams to become either one of the orthogonal large beams and the parallel large beams The refractory coating of the large beam and the small beam is in a state reduced more than the refractory coating applied to the large beam, which is one of the orthogonal large beam and the parallel large beam.

  The fireproof structure according to a second aspect of the present invention is the fireproof structure according to the first aspect of the present invention, wherein a frame for supporting the floor slab is formed by using the plurality of column members, the plurality of large beams, and the small beams, and the floor The slab is restrained by a peripheral frame provided adjacent to the frame in the material axis direction of the large beam which is the other of the orthogonal beam and the parallel beam with reduced fireproof coating. .

  The fireproof structure according to a third aspect of the present invention is the fireproof structure according to the second aspect, wherein the floor slab is provided with a reinforcing bar disposed in the floor slab supported by the frame in the floor slab supported by the peripheral frame. It is characterized by being provided continuously with the rebar.

  The fire-resistant structure according to a fourth aspect of the present invention is the fire-resistant structure according to any one of the first to third aspects, wherein the large beam and the small beam, which are the other of the orthogonal large beam and the parallel large beam with reduced fire-resistant coating, are substantially in cross section. An H-shaped steel having an H shape is used.

  The fireproof structure according to a fifth aspect of the present invention is the fireproof structure according to any one of the first to fourth aspects, wherein the column member is an H-shaped steel having a substantially H-shaped cross section, a square steel pipe having a substantially rectangular cross section, or a circular steel pipe having a substantially circular cross section. A concrete-filled steel pipe, a reinforced concrete column, or a steel-framed reinforced concrete column in which concrete is filled in the steel pipe is used.

  In the fireproof structure according to a sixth aspect of the present invention, in any one of the first to fifth aspects, an RC slab or a synthetic slab is used as the floor slab.

  The fireproof structure according to a seventh aspect of the present invention is the fireproof structure according to any one of the first to sixth aspects, wherein the large beam and the small beam which are the other of the orthogonal large beam and the parallel large beam in which the fireproof coating is reduced, It is characterized by being in a state where is not applied.

  A fireproof structure according to an eighth aspect of the present invention is a fireproof structure provided in a beam member of a building, and includes a plurality of column members, a plurality of large beams installed on the column members, and a floor slab provided above the large beams. The plurality of large beams includes a pair of first large beams facing each other and a pair of second large beams facing each other, and the first large beams and the second large beams are substantially orthogonal to each other. A fire-resistant coating is provided on one of the first and second beams, and the fire-resistant coating on the beam serving as the other of the first and second beams, The present invention is characterized in that the state is reduced as compared with the fireproof coating applied to the large beam which is one of the first large beam and the second large beam.

  According to 1st invention-8th invention, although a fireproof coating is given to any one of an orthogonal large beam and a parallel large beam, the fireproof coating of the other large beam of an orthogonal large beam and a parallel large beam is reduced. Thus, the thermal expansion in the in-plane direction of the floor slab is allowed and the amount of deflection of the floor slab is suppressed, so that the fire resistance performance in the building can be improved.

  According to the first to eighth aspects of the invention, the fireproof coating is applied to any one of the orthogonal large beam and the parallel large beam, but the fireproof coating of the other large beam and the small beam is reduced. As a result, it is possible to realize cost reduction and shortening of the construction period by reducing the fireproof coating on some large beams and small beams.

  In particular, according to the second and third inventions, the floor slab supported by the frame serving as the fire chamber is restrained by the peripheral frame provided adjacent to the frame, thereby suppressing the amount of deflection of the floor slab. Therefore, it becomes possible to improve the fire resistance in the building.

  In particular, according to the seventh aspect of the present invention, the large beam and the small beam which are either the other of the orthogonal large beam and the parallel large beam in which the fireproof coating is reduced are not subjected to the fireproof coating, thereby reducing the fireproof coating. Significant cost reduction and shortening of construction period can be realized.

It is a perspective view which shows the fireproof structure to which this invention is applied. (A) is a top view which shows the frame of the fireproof structure to which this invention is applied, (b) is a top view which shows the floor slab supported by a frame. (A) is a pillar member of H section steel in a fireproof structure to which the present invention is applied, (b) is a pillar member of a square steel pipe, and (c) is a sectional view showing a pillar member of a circular steel pipe. (A) is a column member of the concrete filling steel pipe in the fireproof structure to which this invention is applied, (b) is a column member of a reinforced concrete column, (c) is sectional drawing which shows the column member of a steel frame reinforced concrete column. (A) is a cross-sectional view showing a large beam in a fireproof structure in which the present invention is applied, (b) is a small beam in a reduced fireproof covering state, and (c) is a cross-sectional view showing a large beam in a reduced fireproof covering state. (A) is a cross-sectional view showing a small beam in a fireproof structure in which the present invention is applied, and (b) is a cross-sectional view showing a large beam in a fireproof structure. (A) is a cross-sectional view showing a small beam in which a part of the H-section steel in the fireproof structure to which the present invention is applied is in a non-fireproof coating state, and (b) is a cross-sectional view in which a part of the H-section steel is in a fireproof coating state It is. (A) is the floor slab of RC slab in the fireproof structure to which this invention is applied, (b) is sectional drawing which shows the floor slab of a synthetic | combination slab. It is a top view which shows the surrounding frame provided adjacent to the material axis direction of the parallel large beam by which the fireproof coating was reduced with the frame in the fireproof structure to which this invention is applied. It is a top view which shows the surrounding frame provided adjacent to the material axis direction of the orthogonal large beam by which the fireproof coating was reduced with the frame in the fireproof structure to which this invention is applied. It is sectional drawing which shows the floor slab supported by the frame in the fireproof structure to which this invention is applied, and restrained by the surrounding frame. It is a top view which shows the parallel large beam which makes the strong axis direction of a column member the material axis direction in the frame in the fireproof structure to which this invention is applied. It is a top view which shows the parallel large beam which makes the weak axis direction of a column member the material axis direction in the frame in the fireproof structure to which this invention is applied. (A) is a perspective view which shows the analysis model of the lowest layer of an 8-story office building, (b) is a perspective view which shows the floor slab which sinks and deform | transforms into a substantially hammock shape. (A) is an analysis model of case 1 in which the frame is not constrained by the peripheral frame, (b) is an analysis model of case 2 in which the frame is constrained by the peripheral frame, and (c) is a case 3 that is a fireproof structure to which the present invention is applied. It is a perspective view which shows the analysis model. (A) is a perspective view which shows the floor slab which bent and deform | transformed in the depth direction, (b) is a graph which shows the relationship between heating time and the maximum deflection amount of a floor slab by the analysis model of case1-case3. . It is a perspective view which shows the state in which the small beam is not provided with the fireproof structure to which this invention is applied.

  Hereinafter, the form for implementing the fireproof structure 1 to which this invention is applied is demonstrated in detail, referring drawings.

  As shown in FIG. 1, the fireproof structure 1 to which the present invention is applied is provided on a beam member of a building such as a house, a school, an office, or a hospital facility. The fireproof structure 1 to which the present invention is applied is provided in a one-story building having a single level, or a low-rise or high-rise building having a plurality of levels.

  The fireproof structure 1 to which the present invention is applied includes a plurality of column members 2, a plurality of large beams 3 installed on the column members 2, a small beam 4 provided on the inner side surrounded by the plurality of large beams 3, a large beam 3 and a small beam The floor slab 5 is provided above the beam 4 and is provided at each level of a steel structure building that requires fireproof performance.

  In the fireproof structure 1 to which the present invention is applied, a frame 7 for supporting the floor slab 5 is formed by using a plurality of column members 2, a plurality of large beams 3 and one or a plurality of small beams 4. The fireproof structure 1 to which the present invention is applied is provided with a plurality of large beams 3 extending in the depth direction X and the width direction Y of the building, and a plurality of column members 2 extending in the height direction Z of the building are provided at the four corners of the frame 7. Placed in.

  As shown in FIG. 2, the frame 7 is formed to have a substantially rectangular shape or the like in the depth direction X and the width direction Y. As shown in FIG. 2A, the frame 7 is provided with a pair of large beams 3 on the front side and the deep side in the depth direction X, and a pair of large beams 3 on the right side and the left side in the width direction Y.

  The frame 7 is provided on the two pillar members 2 provided on the near side in the depth direction X with the large beam 3 extending in the width direction Y on the near side in the depth direction X and on the far side in the depth direction X. A large beam 3 extending in the width direction Y on the back side in the depth direction X is installed on the two pillar members 2 formed.

  The frame 7 includes two pillar members 2 provided on the right side in the width direction Y and a large beam 3 extending in the depth direction X on the right side in the width direction Y and 2 provided on the left side in the width direction Y. A large beam 3 extending in the depth direction X on the left side in the width direction Y is installed on the column member 2.

  The plurality of large beams 3 include a pair of orthogonal large beams 31 provided substantially orthogonal to the small beams 4 and a pair of parallel large beams 32 provided substantially parallel to the small beams 4. The plurality of large beams 3 are connected to the right and left column members 2 in the width direction Y at both ends 30 of the orthogonal large beam 31, and parallel large beams 32 to the near side and deep column members 2 in the depth direction X. The both end portions 30 are connected.

  The plurality of large beams 3 includes a pair of large beams 3 on the near side and the deep side in the depth direction X as a pair of orthogonal large beams 31, and a pair of large beams 3 on the right and left sides in the width direction Y as a pair of parallel large beams 32. And In the plurality of large beams 3, both end portions 40 of the small beams 4 are connected to the respective orthogonal large beams 31, and both end portions 40 of the small beams 4 are not connected to the respective parallel large beams 32.

  Each orthogonal large beam 31 is provided so as to extend substantially in a direction perpendicular to the small beam 4 and to be substantially orthogonal to the small beam 4 by being slightly inclined from the direction orthogonal to the small beam 4. Each of the large parallel beams 32 extends in a direction that is strictly parallel to the small beam 4 and is provided substantially parallel to the small beam 4 by being slightly inclined from the direction parallel to the small beam 4. It becomes.

  The frame 7 is formed by installing a pair of orthogonal large beams 31 and a pair of parallel large beams 32 on a plurality of column members 2 and a predetermined number of small beams 4 mounted on the pair of orthogonal large beams 31. As shown in FIG. 2 (b), a floor slab 5 formed in a substantially rectangular shape is placed on and fixed to the frame 7 with respect to the orthogonal large beam 31, the parallel large beam 32 and the small beam 4.

  The column member 2 is made of a steel material or the like having a predetermined cross-sectional shape with respect to the height direction Z, and a heat insulating material such as rock wool or glass wool is wound or blown around the outer surface of the column member 2. Used with fireproof coating.

  As shown in FIG. 3A, the column member 2 is mainly made of an H-shaped steel 6 having a substantially H-shaped cross section having an upper flange 61, a web 62, and a lower flange 63. Further, as shown in FIGS. 3 (b) and 3 (c), the column member 2 has a substantially hollow rectangular steel pipe 21 such as a square steel pipe 21 or the like, or a rectangular steel pipe 21 having a substantially rectangular cross section, or Alternatively, a circular steel pipe 22 having a substantially circular cross section may be used.

  As the column member 2, as shown in FIG. 4A, a concrete-filled steel pipe in which the concrete 9 is filled in the inside 20 of the steel pipe may be used. Further, as shown in FIG. 4 (b), a reinforced concrete column 23 in which a reinforcing bar 90 such as a deformed reinforcing bar is embedded in the concrete 9 may be used as the column member 2. Furthermore, as the column member 2, as shown in FIG. 4C, a steel reinforced concrete column 24 in which a steel frame material such as a reinforcing bar 90 and an H-shaped steel 6 is embedded in the concrete 9 may be used.

  As shown in FIG. 5, the large beam 3 and the small beam 4 are made of, for example, H-section steel 6 having a substantially H-shaped cross section having an upper flange 61, a web 62 and a lower flange 63. At this time, the plurality of large beams 3 are provided with a fireproof coating by winding or spraying a heat insulating material such as rock wool or glass wool on one of the orthogonal large beams 31 and the parallel large beams 32.

  As shown in FIG. 5A, the plurality of large beams 3 have a fireproof coating in which a pair of orthogonal large beams 31 are provided with a fireproof coating when both of the pair of orthogonal large beams 31 are provided with a heat insulating material such as rock wool. State P is entered. In addition, when a plurality of large beams 3 are provided with a heat insulating material such as rock wool on both of the pair of parallel large beams 32, the pair of parallel large beams 32 are in a fireproof coating state P in which the fireproof coating is applied.

  On the other hand, as shown in FIG. 5 (b), the fireproof coating of the small beam 4 is reduced more than the fireproof coating applied to the large beam 3 which is either the orthogonal large beam 31 or the parallel large beam 32. It becomes fireproof covering state R. Further, as shown in FIG. 5 (c), the fireproof coating of the large beam 3 which is the other of the orthogonal large beam 31 and the parallel large beam 32 is also applied to the large beam 3 which is either the orthogonal large beam 31 or the parallel large beam 32. The reduced fireproof coating state R is reduced as compared with the fireproof coating.

  The fireproof covering state P is, for example, according to the “Glowing Rock Wool Covered Fireproof Structure Construction Quality Control Guidelines (Rockwool Industry Association Spraying Section)” for the thickness of rock wool or the like of the orthogonal beam 31 or the parallel beam 32. When 1 hour fire resistance is required, it is 25 mm. When 2 hours fire resistance is required, it is 45 mm. When 3 hours fire resistance is required, it is 65 mm.

  On the other hand, the reduced fireproof covering state R includes a state in which the fireproof covering by rock wool or the like is somewhat applied, although the fireproof covering by rock wool or the like is reduced compared to the fireproof covering state P. The coating thickness of rock wool or the like in the reduced fireproof coating state R is, for example, about 1/10 to 1/2 of the coating thickness in the fireproof coating state P corresponding to each fireproof performance.

  In addition, as shown in FIG. 6, the large beam 3 and the small beam 4 which are either the orthogonal large beam 31 and the parallel large beam 32 in which the fireproof coating is reduced are in a non-fireproof coating state U in which the fireproof coating is not applied. The reduced fireproof covering state R may be obtained. Further, as shown in FIG. 7, the large beam 3 and the small beam 4 which are the other of the orthogonal large beam 31 and the parallel large beam 32 in which the fireproof coating is reduced are fireproofed by rock wool or the like only on a part of the H-shaped steel 6. The reduced fireproof coating state R may be provided.

  Note that the H-beam 6 having a substantially H-shaped cross section is used for the large beam 3 and the small beam 4 which are the other of the orthogonal large beam 31 and the parallel large beam 32 with reduced fireproof coating. On the other hand, as the large beam 3 which is one of the orthogonal large beam 31 and the parallel large beam 32 to which the fireproof coating is applied, the H-section steel 6 having a substantially H-shaped cross section is used and the large beam 3 made of reinforced concrete is used. May be.

  As the floor slab 5, for example, as shown in FIG. 8A, an RC slab 51 in which reinforcing bars 90 such as deformed reinforcing bars arranged in a lattice shape or the like are embedded in the concrete 9 is used. Further, as shown in FIG. 8B, the floor slab 5 may be a synthetic slab 52 in which concrete 9 is provided above a deck plate 91 such as a steel plate formed in a substantially wave shape.

  As shown in FIGS. 9 and 10, the fireproof structure 1 to which the present invention is applied is assumed to be a large beam that receives a heat input from the frame 7 that becomes a fire room, assuming a predetermined frame 7 at the time of the fire as a fire room. This is to properly evaluate the actual behavior of 3 etc. At this time, the fireproof structure 1 to which the present invention is applied is adjacent to the depth direction X or the width direction Y of the frame 7 serving as a fire chamber, and includes a plurality of column members 2, a plurality of large beams 3, and one or a plurality of small beams 4. A peripheral frame 70 using is used.

  The fireproof structure 1 to which the present invention is applied is adjacent to the frame 7 assumed as a fire chamber in the material axis direction α of the large beam 3 which is the other of the orthogonal large beam 31 and the parallel large beam 32 with reduced fireproof coating. A peripheral frame 70 assumed as a room temperature room is provided.

  In the fireproof structure 1 to which the present invention is applied, the column member 2 and the large beam 3 arranged at the boundary between the frame 7 serving as a fire room and the peripheral frame 70 serving as a room temperature room are used in common. And the fireproof structure 1 to which this invention is applied becomes the fireproof covering state P in which the large beam 3 arrange | positioned at the boundary of the frame 7 used as a fire room and the peripheral structure 70 used as a normal temperature room was given fireproof coating.

  In the fireproof structure 1 to which the present invention is applied, when the frame 7 is arranged on the inner side of the building, the peripheral frame 70 is provided on both sides of the frame 7 in the material axis direction α of the large beam 3 with reduced fireproof coating. It is done. In addition, when the frame 7 is arranged on the outer peripheral side of the building, the fireproof structure 1 to which the present invention is applied has a peripheral frame only on one side of the frame 7 in the material axis direction α of the large beam 3 in which the fireproof coating is reduced. 70 is provided.

  As shown in FIG. 9, when the parallel large beam 32 is in a reduced fireproof covering state R in which the fireproof coating is reduced in the frame 7 serving as a fire chamber, the peripheral frame 70 is particularly in the material axis direction α of the parallel large beam 32. And provided next to the frame 7. At this time, the orthogonal large beam 31 arranged at the boundary between the frame 7 serving as the fire chamber and the peripheral frame 70 serving as the room temperature chamber is in the fireproof coating state P where the fireproof coating is applied.

  As shown in FIG. 10, when the orthogonal large beam 31 is in the reduced fireproof covering state R in which the fireproof coating is reduced in the frame 7 that becomes a fire room, the peripheral frame 70 is particularly in the material axis direction α of the orthogonal large beam 31. And provided next to the frame 7. At this time, the parallel girder 32 arranged at the boundary between the frame 7 serving as a fire chamber and the peripheral frame 70 serving as a room temperature chamber is in a fireproof coating state P with a fireproof coating.

  Here, as shown in FIG. 11, the floor slab 5 supported by the frame 7 serving as a fire room is fixed to a girder 3 arranged at the boundary between the frame 7 serving as a fire room and the peripheral frame 70 serving as a room temperature room. As a result, the frame is restrained by the peripheral frame 70 provided adjacent to the frame 7. In addition, in FIG. 11, illustration of the fireproof coating | cover of the big beam 3 arrange | positioned in the boundary with the surrounding frame 70 is abbreviate | omitted.

  In addition, the floor slab 5 supported by the frame 7 serving as a fire room is a room temperature room in which the reinforcing bars 90 arranged in the floor slab 5 straddle the large beam 3 arranged at the boundary with the peripheral frame 70. You may provide continuously with the reinforcing bar 90 arrange | positioned in the floor slab 5 supported by the periphery frame 70. FIG. At this time, the floor slab 5 supported by the frame 7 serving as a fire chamber transmits the tensile force T from the reinforcing bar 90 in the floor slab 5 of the frame 7 to the reinforcing bar 90 in the floor slab 5 of the peripheral frame 70. Thus, the frame is restrained by the peripheral frame 70 provided adjacent to the frame 7.

  In the fireproof structure 1 to which the present invention is applied, in addition to the column member 2 having no anisotropy in the depth direction X or the width direction Y, as shown in FIG. A column member 2 such as an H-section steel 6 having anisotropy may be used with the width direction Y as the weak axis direction W. Moreover, as shown in FIG. 13, the fireproof structure 1 to which the present invention is applied includes a depth direction X as a weak axis direction W, a width direction Y as a strong axis direction S, and an H-section steel 6 having anisotropy. Column member 2 may be used. In FIGS. 12 and 13, the illustration of the fireproof coating of the column member 2 is omitted.

  At this time, in the fireproof structure 1 to which the present invention is applied, as shown in FIG. 12, when the column member 2 having the width direction Y as the weak axis direction W is used, the strong axis direction S of the column member 2 is used as the material. The parallel girder 32 having the axial direction α may be in the reduced fireproof covering state R, and the orthogonal large beam 31 may be in the fireproof covering state P. Further, the parallel large beam 32 having the strong axis direction S of the column member 2 as the material axis direction α may be set as the fireproof covering state P, and the orthogonal large beam 31 may be set as the reduced fireproof covering state R.

  As shown in FIG. 13, in the fireproof structure 1 to which the present invention is applied, when the column member 2 having the depth direction X as the weak axis direction W is used, the weak axis direction W of the column member 2 is set to the material axis direction α. It is also possible to set the parallel large beam 32 as the reduced fireproof covering state R and the orthogonal large beam 31 as the fireproof covering state P. Further, the parallel large beam 32 having the material axis direction α as the weak axis direction W of the column member 2 may be set as the fireproof covering state P, and the orthogonal large beam 31 may be set as the reduced fireproof covering state R.

  Moreover, the fireproof structure 1 to which the present invention is applied increases the material length L1 of either the orthogonal large beam 31 or the parallel large beam 32 and shortens the other material length L2 of the orthogonal large beam 31 or the parallel large beam 32. You can also At this time, in the fireproof structure 1 to which the present invention is applied, any of the large beams 3 having the short material length L2 may be set to the reduced fireproof covering state R and any of the large beams 3 having the long material length L1 may be set to the fireproof covering state P. Moreover, the fireproof structure 1 to which the present invention is applied can also set any large beam 3 having a long material length L1 as a reduced fireproof covering state R and any large beam 3 having a short material length L2 to be in a fireproof covering state P. .

  Here, in the fireproof structure 1 to which the present invention is applied, as shown in FIG. 14 (a), an earthquake resistant design was performed in evaluating the actual behavior of the large beam 3 and the like which receive fire heat input in the frame 7 serving as a fire room. The analysis model is for the bottom layer of an 8-story office building. At this time, in the frame 7 serving as a fire chamber, the large beam 3, the small beam 4, the floor slab 5, etc. are subjected to fire heat input, so that the floor slab 5 sinks into a substantially hammock shape as shown in FIG. And will be deformed.

In this analysis model, the length of the column member 2 is 4000 mm, the length of the large beam 3 and the small beam 4 is 6000 mm, the column member 2 is loaded with 4310 kN from above, and the weight of the frame 7 is 4900 kN / m ^2. It was supposed to be loaded. In this analysis model, the orthogonal large beam 31 is H-800 × 400 × 14 × 28 (SN400B) in the fireproof covering state P, and the parallel large beam 32 is H-700 × 300 × 14 × 28 (SN490B) in the fireproof covering state P. The small beam 4 is H-400 × 200 × 8 × 13 (SN490B) in the reduced fireproof covering state R, and the column member 2 is □ -500 × 28 (BCP325) in the fireproof covering state P. Further, in this analysis model, as shown in FIG. 11, the temperature boundary condition on the upper surface 5a of the floor slab 5 in the frame 7 serving as a fire room is 20 ° C. The temperature boundary condition on the outer surface of the steel 6 was 2 hours heating in accordance with the ISO834 standard heating curve.

  Next, in the analysis model shown in FIG. 15, the dimensions of the column member 2, the dimensions of the beam 4 and the temperature boundary condition are made the same as those in the analysis model shown in FIG. The small beam 4 was provided. Here, in the case 1 analysis model shown in FIG. 15A, it is assumed that the frame 7 serving as a fire chamber is not restrained by the peripheral frame 70, and in the case 2 analysis model shown in FIG. 7 is bound to the peripheral frame 70. Further, in the analysis model of case 3 shown in FIG. 15 (c), it is assumed that the frame 7 serving as a fire chamber is constrained by the peripheral frame 70, and the orthogonal large beam 31 is formed of a fire-resistant coating as in the fire-resistant structure 1 to which the present invention is applied. Although the fireproof coating state P is applied, the parallel large beam 32 and the small beam 4 are in the reduced fireproof coating state R where the fireproof coating is not applied.

  Here, in the frame 7 serving as the fire chamber, as shown in FIG. 14, the temperature of the small beam 4 in the reduced fireproof coating state R not subjected to the fireproof coating is increased by receiving heat input from the fire. The member yield strength is significantly reduced. However, in the frame 7 serving as a fire chamber, the floor slab 5 sinks and deforms in a substantially hammock-like shape, so that an in-plane tensile force T acts on the floor slab 5, so that the member strength of the small beam 4 decreases. Nevertheless, the amount of deflection when the floor slab 5 sinks is reduced.

  Furthermore, in the frame 7 serving as a fire chamber, when both the orthogonal large beam 31 and the parallel large beam 32 are covered with fireproof coating, all four sides of the floor slab 5 are constrained by the large beam 3, so that the thermal expansion of the floor slab 5 is performed. Is restricted in the in-plane direction. At this time, in the frame 7 serving as a fire chamber, the thermal expansion of the floor slab 5 is limited in the in-plane direction, and the subsidence in the out-of-plane direction of the floor slab 5 is promoted, whereby the floor slab 5 is submerged. Increases the amount of deflection.

  On the other hand, in the frame 7 serving as a fire chamber, when the fireproof coating on one of the orthogonal large beam 31 and the parallel large beam 32 is reduced, as shown in FIG. The part is not restrained, and the thermal expansion of the floor slab 5 is allowed in the in-plane direction. At this time, in the frame 7 serving as a fire chamber, the thermal expansion of the floor slab 5 is allowed in the in-plane direction, and the floor slab 5 is deformed by being bent only in a predetermined direction in the in-plane direction. The amount of deflection when sinking is reduced.

  According to this analysis result, as shown in FIG. 16 (b), when the analysis model of case 1 and the analysis model of case 2 are compared, when 2 hours have elapsed after the start of heating, the analysis model of case 1 In the analysis model of case 2, it can be seen that the maximum deflection amount in the height direction Z when the floor slab 5 sinks becomes small.

  Further, according to this analysis result, when the analysis model of case 2 and the analysis model of case 3 are compared, the floor slab 5 in the analysis model of case 3 is more than the analysis model of case 2 when two hours have elapsed after the start of heating. It can be seen that the maximum amount of deflection in the height direction Z when sinking is reduced.

  Therefore, in the fireproof structure 1 to which the present invention is applied, the fireproof coating is applied to any one of the orthogonal large beams 31 and the parallel large beams 32, but the other large beams 3 of the orthogonal large beams 31 and the parallel large beams 32 are provided. By reducing the fireproof coating, as shown in FIG. 16A, thermal expansion in the in-plane direction of the floor slab 5 is allowed, and the amount of deflection of the floor slab 5 is suppressed. And the fireproof structure 1 to which the present invention is applied suppresses the amount of deflection of the floor slab 5, maintains the supporting force against the vertical load, and prevents collapse, so that the fireproof performance in the building can be improved. It becomes.

  In addition, the fireproof structure 1 to which the present invention is applied has a fireproof coating applied to any one of the orthogonal large beam 31 and the parallel large beam 32, but the other large beam 3 of the orthogonal large beam 31 and the parallel large beam 32 and By reducing the fireproof coating of the small beams 4, it is possible to realize cost reduction and shortening the work period by reducing the fireproof coating on some of the large beams 3 and the small beams 4.

  Furthermore, as shown in FIG. 11, the fireproof structure 1 to which the present invention is applied is based on the analysis result comparing the analysis model of case 1 shown in FIG. 15A and the analysis model of case 2 shown in FIG. When the floor slab 5 supported by the frame 7 serving as a fire chamber is restrained by the peripheral frame 70 provided adjacent to the frame 7, the floor slab 5 sinks into a substantially hammock shape and deforms. Since the tensile force T in the inward direction is transmitted and the amount of deflection of the floor slab 5 is suppressed, it is possible to improve the fire resistance performance in the building.

  The fire-resistant structure 1 to which the present invention is applied has a structure in which the large beam 3 and the small beam 4 which are either one of the orthogonal large beam 31 and the parallel large beam 32 in which the fire-resistant coating is reduced, particularly, as shown in FIG. It becomes possible to implement | achieve drastic cost reduction and construction period shortening by reduction of a fireproof coating by becoming the reduced fireproof coating state R of the non-fireproof coating state U which is not given.

  In addition, as shown in FIGS. 12 and 13, the fireproof structure 1 to which the present invention is applied reduces the large beam 3 having the long material length L1 when the short beam 3 having the short material length L2 is set to the reduced fireproof covering state R. The amount of deflection of the floor slab 5 can be suppressed as compared with the fireproof covering state R. On the other hand, in the fireproof structure 1 to which the present invention is applied, when the long beam 3 with the long material length L1 is in the reduced fireproof covering state R, the long beam 3 with the short material length L2 is in the reduced fireproof covering state R. Can also greatly reduce the fireproof coating.

  As shown in FIG. 17, the fireproof structure 1 to which the present invention is applied is provided with a plurality of column members 2, a plurality of large beams 3 installed on the column member 2, and a large beam 3. A floor slab 5 provided above may be provided.

  At this time, the fireproof structure 1 to which the present invention is applied includes, as the plurality of large beams 3, a pair of first large beams 3a facing each other and a pair of second large beams 3b facing each other, and the first large beams 3a The second large beams 3b are provided so as to be substantially orthogonal to each other. In the fireproof structure 1 to which the present invention is applied, in particular, the first large beam 3a shown in FIG. 17 corresponds to the orthogonal large beam 31 shown in FIG. 1, and the second large beam 3b shown in FIG. 17 corresponds to the parallel large beam 32 shown in FIG. Will be.

  And the fireproof structure 1 to which this invention is applied will be in the state by which the fireproof coating was given to any one of the 1st big beam 3a and the 2nd big beam 3b. In addition, the fireproof structure 1 to which the present invention is applied is a large beam in which the fireproof coating of the first beam 3a and the second beam 3b is the other one of the first beam 3a and the second beam 3b. It becomes the state reduced rather than the fireproof coating given to 3.

  As mentioned above, although the example of embodiment of this invention was demonstrated in detail, all the embodiment mentioned above showed only the example of actualization in implementing this invention, and these are the technical aspects of this invention. The range should not be interpreted in a limited way.

1: Fireproof structure 2: Column member 20: Interior 21: Square steel pipe 22: Circular steel pipe 23: Reinforced concrete column 24: Steel-framed reinforced concrete column 3: Large beam 3a: First large beam 3b: Second large beam 30: Both ends 31 of the large beam: Orthogonal Large beam 32: Parallel beam 4: Small beam 40: Both ends 5 of the small beam: Floor slab 5a: Upper surface 5b: Lower surface 51: RC slab 52: Composite slab 6: H-section steel 61: Upper flange 62: Web 63: Lower flange 7: Frame 70: Peripheral frame 9: Concrete 90: Reinforcing bar 91: Deck plate X: Depth direction Y: Width direction Z: Height direction

Claims (8)

A fireproof structure provided on a beam member of a building,
A plurality of column members, a plurality of large beams laid on the column members, a small beam provided on the inner side surrounded by the plurality of large beams, and a floor slab provided above the large beam and the small beam,
The plurality of large beams include a pair of orthogonal large beams provided substantially orthogonal to the small beam, and a pair of parallel large beams provided substantially parallel to the small beam, the orthogonal large beam and the A fireproof coating is applied to any one of the parallel beams,
The fireproof coating of the large beam and the small beam, which is the other of the orthogonal large beam and the parallel large beam, is reduced compared to the fireproof coating applied to the large beam which is either the orthogonal large beam or the parallel large beam. Fireproof structure characterized by being in a state. A frame for supporting the floor slab is formed by using the plurality of pillar members, the plurality of large beams, and the small beams.
The floor slab is constrained by a peripheral frame provided adjacent to the frame in the direction of the material axis of the large beam which is the other of the orthogonal beam and the parallel beam with reduced fireproof coating. The fireproof structure according to claim 1. The floor slab is provided such that a reinforcing bar disposed in a floor slab supported by the frame is continuously provided with a reinforcing bar disposed in a floor slab supported by the peripheral frame. Item 2. The fireproof structure according to item 2. 4. The H-shaped steel having a substantially H-shaped cross section is used for the large beam and the small beam which are the other of the orthogonal large beam and the parallel large beam in which the fireproof coating is reduced. The fireproof structure according to claim 1. The column member may be an H-shaped steel having a substantially H-shaped cross section, a square steel pipe having a substantially rectangular cross-section, a circular steel pipe having a substantially circular cross-section, a concrete-filled steel pipe filled with concrete, a reinforced concrete column, or a steel reinforced concrete. A pillar is used. The fireproof structure according to any one of claims 1 to 4, wherein the pillar is used. The fireproof structure according to any one of claims 1 to 5, wherein the floor slab is an RC slab or a synthetic slab. The fire beam is not applied to the large beam and the small beam which are the other of the orthogonal large beam and the parallel large beam with reduced fire resistance coating. 1. A fireproof structure according to item 1. A fireproof structure provided on a beam member of a building,
A plurality of column members, a plurality of large beams installed on the column members, and a floor slab provided above the large beams,
The plurality of large beams have a pair of first large beams facing each other and a pair of second large beams facing each other, and the first large beams and the second large beams are provided substantially orthogonal to each other, A fireproof coating is applied to one of the first beams and the second beam,
The fire-resistant coating of the first beam, which is the other of the first and second beams, is reduced more than the fire-resistant coating applied to the first beam, the first beam, or the second beam. Fireproof structure characterized by being in a state.

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