WO2020110995A1 - Fire resistant structure design method, fire resistant structure construction method, and fire resistant structure - Google Patents

Abstract

This fire resistant structure design method involves performing: a structure determination step of determining the arrangement of a slab, a plurality of beams to support the slab from underneath, and a post to support the plurality of beams; a fire resistance specification determination step of setting the perimeter of a floor partitioned from the slab so as to be supported from underneath by a fire resistant beam, which is a beam on which a fire resistant coating has been applied; a first support specification determination step of joining an extended beam to a joining corner and setting a section, which is different from the section of the extended beam joined to the joining corner, to be supported by a fire resistant post; and a second support specification determination step of setting the joining corner so as not to be supported directly by a post or so as to be supported from underneath by a reduced fire resistant post, which has less fire resistant coating than the fire resistant post.

Description

Fireproof structure design method, fireproof construction method, and fireproof structure

The present invention relates to a method for designing a refractory structure, a method for constructing a refractory structure, and a refractory structure.
The present application claims priority based on Japanese Patent Application No. 2018-221046 filed in Japan on November 27, 2018, and the content thereof is incorporated herein.

BACKGROUND ART Conventionally, a steel frame structure is known (for example, see Non-Patent Document 1). The steel frame structure is configured by joining columns and beams to each other and supporting a floor (slab) on the beams. The floor is formed in a rectangular shape having a plurality of corners in a plan view. The pillar supports each of the plurality of corners of the floor from below.
In a structure, in order to improve fire resistance performance, a steel frame column or beam may be provided with a fire resistant coating. The pillar with the fireproof coating becomes a fireproof covered pillar. A beam with a fireproof coating is a fireproof beam.

When a structure fires, the temperature of the pillars and beams will rise. However, the refractory-covered columns and the refractory-covered beams maintain constant rigidity and proof stress even when their respective temperatures rise. Therefore, the fireproof covered pillar and the fireproof covered beam can support the floor even in the case of a fire. On the other hand, a pillar and a beam without a fireproof coating, a pillar and a beam with a fireproof coating less than that of a fireproof covered column and a fireproof covered beam lose rigidity and proof strength in the event of a fire. In the event of a fire, their rigidity and yield strength may be considered to be reduced. In a structure including columns and beams that are not covered with fireproof coating, fireproof performance is deteriorated.
Since a great deal of labor is required to apply a fireproof coating to columns and beams, it is desirable to omit the fireproof coating.

Generally, a structure is composed of columns, beams, slabs, and the like. The slab includes a tensile force transmission member. For example, the tensile force transmission member is a reinforcing bar. The structure becomes a refractory structure by applying a fireproof coating to the column to form a fireproof coated column, or by applying a fireproof coating to the beam to form a fireproof coated beam. The slab is divided by a pillar and a beam into a rectangular floor having a plurality of corners in a plan view.

As shown in FIG. 31, in the method for designing a refractory structure for designing a refractory structure 300 disclosed in Patent Document 1, a beam member 303 is provided between a fire-resistant coated column member 301 and a reduced fire-resistant coated column member 302. It is set to be joined. 31 and subsequent figures, columns and beams provided without reducing the fireproof coating are shown with hatching.
The fireproof column member 301 is a column member having a fireproof coating. The reduced fireproof coated column member 302 is a column member in which the fireproof coating is reduced as compared with the fireproof coated column member 301.
In a plan view of the refractory structure 300, the plurality of fireproof covered column members 301 and the plurality of reduced fireproof covered column members 302 are arranged side by side in the width direction E1 and the depth direction E2 with an interval therebetween. The plurality of fireproof coated column members 301 and the plurality of reduced fireproof coated column members 302 are arranged in a grid as a whole. At this time, the column members adjacent to the reduced fireproof coated column member 302 in the width direction E1 and the depth direction E2 are arranged so as to be the fireproof coated column member 301. The beam member 303 joins the plurality of fire-resistant coated column members 301 and the plurality of reduced fire-resistant coated column members 302 that are arranged in a grid pattern.

A synthetic slab 304 is provided on the plurality of beam members 303. Although not shown, the synthetic slab 304 has concrete, a deck plate, and slab muscles (tensile force transmitting members). The deck plate is fixed to the upper surface of the beam member 303 by driving tack bonding, bolt bonding, or the like.
In the fireproof structure 300 configured as described above, the fireproof coated column member 301 can maintain rigidity and proof stress not only in a normal time when the outside temperature is room temperature but also in a fire. On the other hand, the reduced fireproof coated column member 302 can maintain the rigidity and the proof stress in normal times, but cannot maintain the rigidity and the proof stress in a fire. In the event of a fire, it is considered that the reduced fireproof coated column member 302 loses its rigidity and proof stress.

The fire resistant structure 300 at the time of fire deforms as shown in FIGS. 32 and 33. Note that the synthetic slab 304 is not shown in FIG. In FIG. 33, the reduced fireproof coating column member 302 and the synthetic slab 304 after deformation are indicated by a two-dot chain line.
In FIG. 32, the composite slab 304 arranged on the center line M1 connecting the adjacent fire-resistant coated column members 301 is hereinafter referred to as a line slab 304a. The fire-resistant coated column member 301, the reduced fire-resistant coated column member 302, the beam member 303, and the composite slab 304 are affected by gravity not only during normal times but also during a fire.

Since the rigidity and proof stress of the fireproof coated pillar member 301 can be maintained during a fire, the position of the linear slab 304a in the vertical direction E3 is maintained even during a fire, as shown in FIGS. 32 and 33. On the other hand, since the reduced fireproof coating column member 302 loses rigidity and proof stress in the event of a fire, it moves downward (bends) as shown by the chain double-dashed line in FIG.
Since the position in the vertical direction E3 is not held except for the linear slab 304a, each part of the synthetic slab 304 moves downward due to the gravity acting on the synthetic slab 304 as it separates from the linear slab 304a. Therefore, at the time of fire, the synthetic slab 304 is curved so as to be convex upward with the linear slab 304a as the center.
In the curved synthetic slab 304, the concrete receives a compressive force and the slab muscle receives a tensile force, so that the synthetic slab 304 withstands the bending moment B1. The synthetic slab 304 resists gravity acting on the synthetic slab 304 by the bending moment B1.

As described above, in the fireproof structure 300, the fireproof coating of the reduced fireproof coated column member 302 is smaller than that of the fireproof coated column member 301. However, in the refractory structure 300, the robustness of the frame of the refractory structure 300 occurs. Due to this robustness, the composite slab 304 is supported by the fire-resistant coating pillar member 301 in the event of a fire even if the fire-resistant coating of the fire-retardant covering pillar member 302 is reduced.

In the method for calculating the explosion-proof fireproof coating thickness disclosed in Patent Document 2, a test body including a concrete structure and an explosion-proof fireproof coating layer provided on the surface of the concrete structure is produced. Then, the test body is heated to measure the change in temperature over time, and the relationship between the depth of the test body and the temperature is derived. Based on the relationship, it is determined whether the temperature of the concrete structure is equal to or lower than the heat-resistant allowable temperature. Further, the thickness of the explosion-proof fireproof coating layer is calculated based on the result.

The slab structure disclosed in Patent Document 3 includes a large beam, a steel frame small beam, and a slab. The girder has fire resistance and is spanned between columns. The whole or part of the steel beam is not fireproof coated. The steel beam is connected to the girder. The slab is made of reinforced concrete. The slab is supported by a girder and a steel beam.

The fire resistant structure disclosed in Patent Document 4 includes a plurality of pillar members, a plurality of girders, girders, and a floor slab.
Each girder is installed on a pillar member. The plurality of girders have a pair of orthogonal girders provided substantially orthogonal to the girders and a pair of parallel girders provided substantially parallel to the girders. A fireproof coating is applied to either one of the cross girders and the parallel girders (hereinafter referred to as the first girder). The fireproof coating of the girder and the girder that is either the orthogonal girder or the parallel girder is reduced as compared with the fireproof coating applied to the first girder. The cross beam is provided inside the plurality of cross beams. The floor slab is provided above the girders and girders.

Japanese Patent Laid-Open No. 2017-031592 Japanese Patent Laid-Open No. 2008-303646 Japanese Patent Laid-Open No. 2017-190586 Japanese Patent Laid-Open No. 2018-003556

In the method of designing a refractory structure disclosed in Patent Documents 1, 3, and 4, any corner of the floor is supported by a pillar member (pillar). Therefore, the degree of freedom in designing the corners of the floor is limited.
In addition, in patent document 2, there is no description regarding the support structure at the corner of the floor.

The present invention has been made in view of such a problem, and while maintaining fire resistance, increases the degree of freedom in designing the corners of the floor and supports the plurality of corners of the floor. An object of the present invention is to provide a method for designing a refractory structure, a method for constructing a refractory structure, and a refractory structure in which at least one refractory coating of a pillar can be omitted.

In order to solve the above problems, the present invention proposes the following means.
(1) A first aspect of the present invention is, in a slab including a tensile force transmission member, a floor section partitioned into a polygonal shape having a plurality of corners in a plan view, and a fireproof coating applied to the floor section. An annular fireproof beam that supports the surroundings from below, a fireproof coating, and an extension beam that is joined to a joining corner, which is at least one of the plurality of corners of the floor, and a fireproof coating. A refractory covered column supporting a part different from the part connected to the connection corner of the extension beam, and a direction intersecting with each other in a plane of the floor part is a first intersecting direction and a second intersecting direction. At this time, the tensile force transmitting member transmits the tensile force between the ends of the floor in the first intersecting direction and the tensile force between the ends of the floor in the second intersecting direction, respectively. A method of designing a refractory structure for designing, wherein by performing a structural calculation, the slab, a plurality of beams that support the slab from below, and an arrangement of columns that support the plurality of beams are provided. A structure determining step to determine, a perimeter of the floor section partitioned from the slab, a refractory specification determining step to set so as to be supported from below by the refractory-coated beam having a fire-resistant coating on the beam, and the joint corner A first supporting specification determining step of connecting the extension beam to a portion and setting a portion of the extension beam different from the portion connected to the connecting corner portion to be supported by the fireproof coated column; and the connecting corner portion. And a second supporting specification determining step of setting not to be directly supported by a pillar or by supporting from a lower side by a reduced fireproof covered pillar in which the fireproof covering is reduced compared to the fireproof covered pillar. Is the design method.

(2) In the method for designing a refractory structure according to (1) above, after the refractory specification determination step, the first support specification determination step, and the second support specification determination step, the refractory structure is When heated based on the heating curve defined in ISO 834-11:2014, the maximum value of the deflection of the floor portion at a desired heating time is less than the threshold value K defined by the equation (1). You may perform the determination process which determines whether or not.
K=(L+1)/30 ··· (1)
Here, L is the length (m) of the first span along the main surface of the floor, and l is the length (m of the second span along the main surface of the floor and intersecting the first span. ).

(3) In the design method of the refractory structure according to (2), when the maximum value of the bending of the floor is not less than the threshold value K in the determination step, the refractory specification determination step is divided from the slab. At least one of the plurality of beams to which the refractory coating is applied is changed so that at least one of the shape and size of the floor portion to be changed is changed, and further, the first support specification determining step and the second support are performed. The determination step may be performed after the specification determination step.

(4) A second aspect of the present invention is, in a slab including a tensile force transmission member, a floor section partitioned into a polygonal shape having a plurality of corners in a plan view, and a fireproof coating applied to the floor section. A refractory coated beam that supports the periphery from below, and a refractory coated beam that supports the refractory coated beam, and a first refractory coated column in which a part of itself and the refractory coated beam are formed in an annular shape as a whole, An extension beam having a fireproof coating and joined to a connecting corner which is at least one of the plurality of corners of the floor, and a fireproof coating having been joined to the connecting corner of the extension beam A second refractory-covered column that supports a part different from the part, and the tensile force transmission member has a first crossing direction and a second crossing direction that intersect with each other in the plane of the floor. A refractory structure for designing a refractory structure that transmits a tensile force between the ends of the floor in the first intersecting direction and a tensile force between the ends of the floor in the second intersecting direction, respectively. A method for designing, wherein a structural calculation is performed to determine an arrangement of the slab, a plurality of beams that support the slab from below, and a plurality of columns that support the plurality of beams, and the slab So that the periphery of the floor section partitioned from is supported from below by the fire-resistant coated beam in which the beam has a fire-resistant coating and the part of the first fire-resistant coated column in which the column has a fire-resistant coating. A step of setting a fireproof specification and a step of connecting the extension beam to the joint corner and setting a portion of the extension beam different from a portion joined to the joint corner to be supported by the second refractory-covered column The first supporting specification determining step and the connecting corners are not directly supported by columns, or are supported from below by reduced fireproof coated columns in which the fireproof coating is reduced compared to the first fireproof coated columns. It is a method for designing a refractory structure that performs a second supporting specification determining step to be set.

(5) In the method for designing a refractory structure according to (4), after the refractory specification determination step, the first support specification determination step, and the second support specification determination step, the refractory structure is When heated based on the heating curve defined in ISO 834-11:2014, the maximum value of the deflection of the floor portion in a desired heating time is less than a threshold value K defined by the equation (2). You may perform the determination process which determines whether or not.
K=(L+1)/30 ··· (2)
Here, L is the length (m) of the first span along the main surface of the floor, and l is the length (m of the second span along the main surface of the floor and intersecting the first span. ).

(6) In the design method of the refractory structure according to (5), when the maximum value of the bending of the floor is not less than the threshold value K in the determination step, the refractory specification determination step is divided from the slab. At least one of the shape and size of the floor portion to be changed is performed by changing at least a part of the plurality of beams for applying the fireproof coating and the plurality of columns for applying the fireproof coating, and further, The determining step may be performed after the first supporting specification determining step and the second supporting specification determining step.
(7) A third aspect of the present invention is a refractory structure designed by the method for designing a refractory structure according to any one of (1) to (6) above.

(8) A fourth aspect of the present invention is, in a slab including a tensile force transmission member, a floor section partitioned into a polygonal shape having a plurality of corners in a plan view, and a fireproof coating applied to the floor section. An annular fireproof beam that supports the surroundings from below, a fireproof coating, and an extension beam that is joined to a joining corner, which is at least one of the plurality of corners of the floor, and a fireproof coating. A refractory covered column supporting a part different from the part connected to the connection corner of the extension beam, and a direction intersecting with each other in a plane of the floor part is a first intersecting direction and a second intersecting direction. At this time, the tensile force transmitting member transmits the tensile force between the ends of the floor in the first intersecting direction and the tensile force between the ends of the floor in the second intersecting direction, respectively. A method for constructing a refractory structure for constructing, wherein the slab, a plurality of beams supporting the slab from below, and a beam-column construction step for constructing a column supporting the plurality of beams, and By applying a fireproof coating to the beam to form the fireproof coated beam, a coating construction step of supporting the periphery of the floor section partitioned from the slab from below by the fireproof coated beam, and the extension beam at the joint corner. A first supporting step of supporting a part of the extension beam different from the part connected to the connecting corner with the refractory-coated column, and not connecting the connecting corner directly to the column, There is a second supporting step of supporting from below from a fire-retardant coated pillar in which the fire-resistant coating is reduced compared to the fire-resistant coated pillar.

(9) A fifth aspect of the present invention is, in a slab including a tensile force transmission member, a floor section partitioned into a polygonal shape having a plurality of corners in a plan view, and a fireproof coating applied to the floor section. A refractory coated beam that supports the periphery from below, and a refractory coated beam that supports the refractory coated beam, and a first refractory coated column in which a part of itself and the refractory coated beam are formed in an annular shape as a whole, An extension beam having a fireproof coating and joined to a connecting corner which is at least one of the plurality of corners of the floor, and a fireproof coating having been joined to the connecting corner of the extension beam A second refractory-covered column that supports a part different from the part, and the tensile force transmission member has a first crossing direction and a second crossing direction that intersect with each other in the plane of the floor. , A refractory structure for constructing a refractory structure that transmits a tensile force between the ends of the floor in the first intersecting direction and a tensile force between the ends of the floor in the second intersecting direction, respectively. A construction method, wherein the slab, a plurality of beams that support the slab from below, and a pillar-beam construction step that constructs a plurality of columns that support the plurality of beams, and a fireproof coating by applying a fireproof coating to the beams. As a covered beam, by applying a fireproof coating to the pillar to form the first fireproof covered pillar, the periphery of the floor section partitioned from the slab is covered with the fireproof covered beam and the part of the first fireproof covered pillar. And a step of connecting the extension beam to the joint corner, and a portion of the extension beam different from the portion joined to the joint corner is covered with the second refractory-covered column. A first supporting step of supporting, and a second support in which the joint corner is not directly supported by a column or is supported from below by a reduced fireproof coated column in which the fireproof coating is reduced compared to the first fireproof coated column. It is a construction method of the refractory structure which performs the steps.

(10) A sixth aspect of the present invention is, in a slab including a tensile force transmission member, a floor section partitioned into a polygonal shape having a plurality of corners in a plan view, and a fireproof coating applied to the floor section. An annular fireproof beam that supports the surroundings from below, a fireproof coating, and an extension beam that is joined to a joining corner, which is at least one of the plurality of corners of the floor, and a fireproof coating. A refractory covered column supporting a part different from the part connected to the connection corner of the extension beam, and a direction intersecting with each other in a plane of the floor part is a first intersecting direction and a second intersecting direction. When, and the joint corner is not directly supported by the column, or is supported from below by the reduced fireproof coating column reduced in the fireproof coating than the fireproof coated column, the tensile force transmission member, The refractory structure transmits tensile force between end portions of the floor portion in the first intersecting direction and tensile force between end portions of the floor portion in the second intersecting direction.

(11) In the refractory structure according to (10), the refractory coating is reduced as compared with the refractory coated beam, the refractory coating is arranged in a region surrounded by the annular refractory coated beam, and an end portion of the refractory coated beam is the refractory structure. A reduced fire resistant coated beam may be provided which is joined to the coated beam and supports the floor portion from below.
(12) In the fireproof structure according to (10) or (11), the polygonal shape may be a rectangular shape.

(13) In the refractory structure according to any one of (10) to (12), the floor for a desired heating time when heated according to a heating curve defined in ISO 834-11:2014. The maximum value of the bending of the portion may be less than the threshold value K defined by the equation (3).
K=(L+1)/30 (3)
Here, L is the length (m) of the first span along the main surface of the floor, and l is the length (m of the second span along the main surface of the floor and intersecting the first span. ).
(14) In the refractory structure according to any one of (10) to (13), the tensile force transmission member extends along the first intersecting direction and is an end of the floor portion in the first intersecting direction. A first reinforcing bar for transmitting a tensile force between the parts, and a second reinforcing bar extending along the second intersecting direction for transmitting a tensile force between the ends of the floor in the second intersecting direction. Good.

(15) A seventh aspect of the present invention is, in a slab including a tensile force transmitting member, a floor section partitioned into a polygonal shape having a plurality of corners in a plan view, and a fireproof coating applied to the floor section. A refractory coated beam that supports the periphery from below, and a refractory coated beam that supports the refractory coated beam, and a first refractory coated column in which a part of itself and the refractory coated beam are formed in an annular shape as a whole, An extension beam having a fireproof coating and joined to a connecting corner which is at least one of the plurality of corners of the floor, and a fireproof coating having been joined to the connecting corner of the extension beam A second refractory-covered column that supports a part different from the part, and when the directions intersecting with each other in the plane of the floor are the first intersecting direction and the second intersecting direction, the joint corner is The column is not directly supported by a column or is supported from below by a reduced fireproof coated column in which the fireproof coating is reduced from the first fireproof coated column, and the tensile force transmission member is in the first intersecting direction of the floor. Is a refractory structure that transmits the tensile force between the ends of the floor part and the tensile force between the ends of the floor part in the second intersecting direction, respectively.

(16) In an eighth aspect of the present invention, a fireproof coating is applied, the fireproof coating is provided, and the fireproof coating is arranged side by side in the first intersecting direction along the horizontal plane, and the first intersecting direction intersects with the first intersecting direction along the horizontal plane. A plurality of refractory-coated columns arranged side by side with a pitch, and a pair of first refractory-coated columns that are provided with a refractory coating and that extend along the first intersecting direction and that are arranged at intervals in the second intersecting direction. A beam and a fireproof coating are applied, extend along the second intersecting direction, are formed to have a length different from the first pitch, and both ends are directly bonded to the pair of first fireproof coated beams. In a slab including a pair of second refractory-covered beams respectively joined to the plurality of refractory-covered columns and a tensile force transmission member, the slab is divided into a rectangular shape having four corners in a plan view, and the pair of first A floor portion whose periphery is supported from below by a fireproof covered beam and the pair of second fireproof covered beams, and a fireproof coating, which is coupled to a joining corner portion which is at least one of the four corner portions of the floor portion. And the joint corner is not directly supported by a column or is supported from below by a reduced refractory coated column in which the refractory coating is less than the refractory coated column, and the tensile force The transmission member transmits the tensile force between the ends of the floor in the first intersecting direction and the tensile force between the ends of the floor in the second intersecting direction, respectively, and the plurality of fireproof coated columns Is a refractory structure that supports a portion of the extension beam that is different from the portion connected to the connection corner.

In the configuration described in (1) above, the fact that the joint corner is not directly supported by the column means that the joint corner is not supported by the column without the beam. However, the fact that the joint corner is not directly supported by the pillar does not mean that the joint corner is supported by the pillar via the beam.

According to the configuration described in the above (1), by performing the structure determining step and the fireproof specification determining step, the circumference of the floor is covered with an annular fireproof covered beam that can maintain a certain rigidity and yield strength even from a fire. Set to support. The tensile force transmitting member included in the floor portion transmits the tensile force between the end portions of the floor portion in the first intersecting direction and the tensile force between the end portions of the floor portion in the second intersecting direction. At the time of fire, due to gravity or the like acting on the floor, the center of the floor in a plan view is bent downward so as to be convex. However, due to the so-called membrane effect, the perimeter of the floor is supported by the fireproof beam. Then, the tensile force transmitting member extended by the bending of the floor portion transmits the tensile force in each of the first intersecting direction and the second intersecting direction, so that the central portion of the floor portion is supported. Therefore, it is possible to set the fireproof performance of the fireproof structure to be maintained at the same level as the conventional one. The fireproof performance of the fireproof structure here means to prevent the floor from bending during a fire and to prevent the external force from becoming larger than the bending resistance.
In the first support specification determining step, the joint corners are set to be supported by the fireproof coated column via the extension beam. Further, in the second supporting specification determining step, the joint corners are set so as not to be directly supported by the columns or supported from below by the reduced fireproof coated columns. Therefore, it is possible to increase the degree of freedom in designing at the joint corner of the floor and to omit the fireproof coating of the column supporting at least one corner.

According to the configuration described in the above (8), by performing the pillar-beam construction process and the covering construction process, the circumference of the floor is covered by the annular fireproof covering beam that can maintain constant rigidity and proof stress even in the case of a fire from below. Support. The tensile force transmitting member included in the floor portion transmits the tensile force between the end portions of the floor portion in the first intersecting direction and the tensile force between the end portions of the floor portion in the second intersecting direction. At the time of fire, due to gravity or the like acting on the floor, the center of the floor in a plan view is bent downward so as to be convex. However, due to the membrane effect, the perimeter of the floor is supported by the fireproof beam. Then, the tensile force transmitting member extended by the bending of the floor portion transmits the tensile force in each of the first intersecting direction and the second intersecting direction, so that the central portion of the floor portion is supported. Therefore, the fire resistance performance of the fire resistant structure can be maintained at the same level as the conventional one.
When the first supporting step is performed, the joint corners are supported by the fireproof coated columns through the extension beams. Further, when the second supporting step is performed, the joint corners are not directly supported by the columns or are supported by the reduced fireproof coated columns from below. Therefore, it is possible to increase the degree of freedom in designing at the joint corner of the floor and to omit the fireproof coating of the column supporting at least one corner.

According to the configuration described in (10) above, the periphery of the floor is supported from below by the annular fireproof covered beam that can maintain constant rigidity and yield strength even in the event of a fire. The tensile force transmitting member included in the floor portion transmits the tensile force between the end portions of the floor portion in the first intersecting direction and the tensile force between the end portions of the floor portion in the second intersecting direction. At the time of fire, due to gravity or the like acting on the floor, the center of the floor in a plan view is bent downward so as to be convex. However, due to the membrane effect, the perimeter of the floor is supported by the fireproof beam. Then, the tensile force transmitting member extended by the bending of the floor portion transmits the tensile force in each of the first intersecting direction and the second intersecting direction, so that the central portion of the floor portion is supported. Therefore, the fire resistance performance of the fire resistant structure can be maintained at the same level as the conventional one.
In the refractory structure, the joint corners are supported by the refractory-coated columns via the extension beams. Moreover, the joint corners are not directly supported by the columns or are supported from below by the reduced fireproof coated columns. Therefore, it is possible to increase the degree of freedom in designing at the joint corner of the floor and to omit the fireproof coating of the column supporting at least one corner.

According to the configuration described in (4) above, by performing the structure determining step and the fireproof specification determining step, it is possible to maintain a certain rigidity and proof strength around the floor even in the event of a fire, and thus it is formed in an annular shape as a whole. The refractory-covered beam and a part of the first refractory-covered column are set to be supported from below. The tensile force transmitting member included in the floor portion transmits the tensile force between the end portions of the floor portion in the first intersecting direction and the tensile force between the end portions of the floor portion in the second intersecting direction. At the time of fire, due to gravity or the like acting on the floor, the center of the floor in a plan view is bent downward so as to be convex. However, due to the membrane effect, the periphery of the floor is supported by the refractory-covered beams and a part of the first refractory-covered columns. Then, the tensile force transmitting member extended by the bending of the floor portion transmits the tensile force in each of the first intersecting direction and the second intersecting direction, so that the central portion of the floor portion is supported. Therefore, it is possible to set the fireproof performance of the fireproof structure to be maintained at the same level as the conventional one.
In the first supporting specification determining step, the joint corner is set to be supported by the second refractory-covered column via the extension beam. Further, in the second supporting specification determining step, the joint corners are set so as not to be directly supported by the columns or supported from below by the reduced fireproof coated columns. Therefore, it is possible to increase the degree of freedom in designing at the joint corner of the floor and to omit the fireproof coating of the column supporting at least one corner.

According to the configuration described in (9) above, by performing the pillar-beam construction process and the covering construction process, it is possible to maintain a certain rigidity and proof strength around the floor even in the event of a fire, and the entire structure is formed in an annular shape. The refractory covered beam and a part of the first refractory covered column are supported from below. The tensile force transmitting member included in the floor portion transmits the tensile force between the end portions of the floor portion in the first intersecting direction and the tensile force between the end portions of the floor portion in the second intersecting direction. At the time of fire, due to gravity or the like acting on the floor, the center of the floor in a plan view is bent downward so as to be convex. However, due to the membrane effect, the periphery of the floor is supported by the refractory-covered beams and a part of the first refractory-covered columns. Then, the tensile force transmitting member extended by the bending of the floor portion transmits the tensile force in each of the first intersecting direction and the second intersecting direction, so that the central portion of the floor portion is supported. Therefore, the fire resistance performance of the fire resistant structure can be maintained at the same level as the conventional one.
When the first supporting step is performed, the joint corner portion is supported by the second refractory-coated column via the extension beam. Further, when the second supporting step is performed, the joint corners are not directly supported by the columns or are supported by the reduced fireproof coated columns from below. Therefore, it is possible to increase the degree of freedom in designing at the joint corner of the floor and to omit the fireproof coating of the column supporting at least one corner.

According to the configuration described in (15) above, the periphery of the floor portion can maintain a certain rigidity and proof stress even in the event of a fire, and is formed by a part of the fireproof covered beam and the first fireproof covered pillar that are formed in an annular shape as a whole. It is supported from below. The tensile force transmitting member included in the floor portion transmits the tensile force between the end portions of the floor portion in the first intersecting direction and the tensile force between the end portions of the floor portion in the second intersecting direction. At the time of fire, due to gravity or the like acting on the floor, the central portion of the floor in plan view is projected downward. However, due to the membrane effect, the periphery of the floor is supported by the refractory-covered beams and a part of the first refractory-covered columns. Then, the tensile force transmitting member extended by the bending of the floor portion transmits the tensile force in each of the first intersecting direction and the second intersecting direction, so that the central portion of the floor portion is supported. Therefore, the fire resistance performance of the fire resistant structure can be maintained at the same level as the conventional one.
In the refractory structure, the joint corners are supported by the second refractory-covered columns via the extension beams. Moreover, the joint corners are not directly supported by the columns or are supported from below by the reduced fireproof coated columns. Therefore, it is possible to increase the degree of freedom in designing at the joint corner of the floor and to omit the fireproof coating of the column supporting at least one corner.

According to the configuration described in (16), the periphery of the floor is supported from below by the annular first refractory-covered beam and second annular refractory-covered beam that can maintain constant rigidity and proof stress even in the event of a fire. The tensile force transmitting member included in the floor portion transmits the tensile force between the end portions of the floor portion in the first intersecting direction and the tensile force between the end portions of the floor portion in the second intersecting direction. At the time of fire, due to gravity or the like acting on the floor, the center of the floor in a plan view is bent downward so as to be convex. However, due to the membrane effect, the perimeter of the floor is supported by the fireproof beam. Then, the tensile force transmitting member extended by the bending of the floor portion transmits the tensile force in each of the first intersecting direction and the second intersecting direction, so that the central portion of the floor portion is supported. Therefore, the fire resistance performance of the fire resistant structure can be maintained at the same level as the conventional one.
In the refractory structure, the joint corners are supported by the refractory-coated columns via the extension beams. Moreover, the joint corners are not directly supported by the columns or are supported from below by the reduced fireproof coated columns. Therefore, it is possible to increase the degree of freedom of design in the joint corner of the floor and to omit the fireproof coating of the column supporting at least one joint corner.

According to the configurations described in (2) and (5) above, it is possible to determine whether or not the maximum value of the flexure of the floor is less than the threshold value in the determination step.
According to the configuration described in (3), when the maximum value of the flexure of the floor portion is not less than the threshold value K, at least one of the shape and the size of the floor portion partitioned from the slab changes in the fireproof specification determining step. In this way, at least a part of the plurality of beams to which the fireproof coating is applied and the plurality of columns to which the fireproof coating is applied are changed. Thereby, in the determination step, it is possible to determine again whether or not the maximum value of the bending of the floor is less than the threshold value K.

According to the configuration described in (6) above, when the maximum value of the flexure of the floor portion is not less than the threshold value K, at least one of the shape and size of the floor portion partitioned from the slab in the fireproof specification determining step, and At least some of the plurality of beams to be fired coated are changed so that the plurality of columns to be fired coated are changed. Thereby, in the determination step, it is possible to determine again whether or not the maximum value of the bending of the floor is less than the threshold value K.
With the configuration described in (7) above, the fireproof structure can be designed by the method for designing the fireproof structure of the present invention. The method for designing a refractory structure of the present invention is a method capable of increasing the degree of freedom in designing at a corner of a floor while maintaining fire resistance. And the design method of the refractory structure of the present invention is a method in which at least one refractory coating of the pillar supporting the plurality of corners of the floor from below can be omitted.

With the configuration described in (11) above, it is possible to prevent the floor from bending during normal times when no fire has occurred.
According to the configuration described in (12) above, it is possible to easily arrange a plurality of floors side by side in a compact manner.

With the configuration described in (13) above, the membrane effect of the floor portion can be effectively exhibited, and the floor portion can be made difficult to bend downward.
According to the configuration described in (14) above, with a simple configuration of the first reinforcing bar and the second reinforcing bar, the tensile force between the ends of the floor in the first crossing direction, and the second crossing direction of the floor. The tensile force between the ends of the can be transmitted respectively.

According to the method for designing a refractory structure, the method for constructing a refractory structure, and the refractory structure of the present invention, while maintaining the fire resistance performance, the degree of freedom in designing at the corner of the floor is increased, and a plurality of floors are provided. At least one refractory coating on the pillars supporting the corners of the can be omitted.

It is the perspective view which penetrated a part of building in which the fireproof structure of a 1st embodiment of the present invention is used. FIG. 2 is a sectional view taken along the section line A1-A1 in FIG. 1. It is a top view which shows the 1st modification of the 1st rebar of the same refractory structure. It is a top view which shows the 2nd modification of the 1st rebar of the same refractory structure. It is a top view showing the 3rd modification of the 1st rebar of the same refractory structure. It is a top view which shows the 4th modification of the 1st rebar of the same refractory structure. FIG. 2 is a cross-sectional view taken along the section line A2-A2 in FIG. 1. It is a flowchart which shows the design method of the fireproof structure of 1st Embodiment of this invention. It is a perspective view explaining the structure determination process in the design method of the same refractory structure. It is a perspective view explaining the fireproof specification deciding process in the design method of the fireproof structure. It is a perspective view which shows the example which adjusted the arrangement|positioning of the fireproof coating beam and the reduced fireproof coating beam in the design method of the same fireproof structure. It is an exploded perspective view of the fireproof structure for explaining external force which usually acts on the fireproof structure. It is an exploded perspective view of the fireproof structure for explaining the external force which acts on the fireproof structure at the time of a fire. It is a flowchart which shows the construction method of the refractory structure of 1st Embodiment of this invention. It is the perspective view which penetrated a part of building in which the fireproof structure of a comparative example is used. It is a longitudinal cross-sectional view of the 1st floor part of the fireproof structure of a comparative example. It is a figure which shows the change of the temperature of each part with respect to time in the refractory structure of a comparative example. It is a figure in the fireproof structure of a comparative example which shows the change of the maximum of deflection of the 1st floor with respect to time. It is a figure in the refractory structure of a comparative example which shows the change of bending strength and external force with respect to time. It is a figure which shows the change of the value of (external force/bending strength) with respect to time in the refractory structure of a comparative example. It is the perspective view which penetrated a part of building in which the fireproof structure of an example is used. It is a figure which shows the change of the temperature of each part with respect to time in the refractory structure of an Example. It is a figure in the fireproof structure of an example which shows the change of the maximum of deflection of the 1st floor with respect to time. It is a figure in the fireproof structure of an example which shows the change of bending strength and external force to time. It is a figure which shows the change of the value of (external force/bending strength) with respect to time in the refractory structure of an Example. It is the perspective view which penetrated a part of building in which the fireproof structure in the modification of a 1st embodiment of the present invention is used. It is the perspective view which penetrated a part of building in which the fireproof structure in the modification of a 1st embodiment of the present invention is used. It is the perspective view which penetrated a part of building in which the fireproof structure in the modification of a 1st embodiment of the present invention is used. It is the perspective view which penetrated a part of building in which the fireproof structure of a 2nd embodiment of the present invention is used. It is a cross-sectional view of a building in which the fire resistant structure of the third embodiment of the present invention is used. It is a perspective view of the conventional fireproof structure. It is a top view which shows typically the principal part of the same fireproof structure at the time of a fire. FIG. 33 is a cross-sectional view taken along the section line A11-A11 in FIG.

(First embodiment)
Hereinafter, a building in which the first embodiment of the refractory structure according to the present invention is used will be described with reference to FIGS. 1 to 28.
As shown in FIG. 1, the building 1 includes a fire resistant structure 11 of the present embodiment and a support structure 41.
The fireproof structure 11 includes a first floor portion (floor portion) 12, first fireproof coated beams (fireproof coated beams) 13A and 13B, second fireproof coated beams (fireproof coated beams) 14A and 14B, and a reduced fireproof coating. Beams 15A, 15B and 15C, fireproof coated columns 16A and 16B, extension beams 17A and 17B, and fireproof coated columns 18A and 18B are provided.
In addition, in FIG. 1 and subsequent figures, the boundary between adjacent fireproof covered beams is shown by a thick solid line. In FIG. 1, the 1st floor part 12 and the 2nd floor part 42 of the support structure 41 mentioned later are shown transparently.

The first floor portion 12 is formed in a plate shape whose vertical direction Z is the thickness direction. The first floor portion 12 has a plurality of (four in the present embodiment) corners 12a, 12b, 12c, 12d (hereinafter, may be abbreviated as corners 12a to 12d) in a plan view when viewed in the vertical direction Z. Is formed in a rectangular shape (polygonal shape). The corners 12a to 12d referred to here mean regions in the first floor 12 in the vicinity of a portion where the adjacent outer edges of the first floor 12 in a plan view are connected to each other. An outer edge of a part of the first floor portion 12 in a plan view extends along the first intersecting direction X within the plane 12e of the first floor portion 12. The flat surface 12e is an outer surface (upper surface, main surface) of the first floor portion 12 orthogonal to the thickness direction of the first floor portion 12 (see also FIG. 2). The outer edge of the remaining portion of the first floor portion 12 in a plan view extends along the second intersecting direction Y within the plane 12e of the first floor portion 12. The first intersecting direction X and the second intersecting direction Y are directions along the plane 12e and are directions orthogonal (intersecting) to each other.
In the present embodiment, the first intersecting direction X and the second intersecting direction Y are directions along the horizontal plane, but the first intersecting direction X and the second intersecting direction Y may also be directions inclined with respect to the horizontal plane. Good.

As shown in FIG. 2, the first floor 12 is a so-called composite slab. The first floor 12 includes a first deck plate (tensile force transmitting member) 21, first concrete (concrete) 22, and reinforcing bars (tensile force transmitting member) 23. The first floor portion 12 does not have to include the first deck plate 21 and the first concrete 22, and the first floor portion 12 does not need to include the reinforcing bar 23 and the first concrete 22. The tensile force transmission member included in the first floor portion 12 is not limited to the first deck plate 21 and the reinforcing bar 23.
For example, the first deck plate 21 is formed by bending a steel plate. The periphery of the first deck plate 21 is supported from below by the first fireproof covered beams 13A, 13B and the second fireproof covered beams 14A, 14B.
The first concrete 22 is formed in a plate shape having the same shape as the first floor portion 12 in a plan view. The first concrete 22 is arranged on the first deck plate 21.

The reinforcing bar 23 is embedded in the first concrete 22. The reinforcing bar 23 includes a plurality of first reinforcing bars 25 and a plurality of second reinforcing bars 26. In FIG. 1, only two first reinforcing bars 25 and two second reinforcing bars 26 are shown by a chain double-dashed line.
As shown in FIGS. 1 and 2, each first reinforcing bar 25 extends along the first intersecting direction X. Each 1st rebar 25 transmits the tensile force between the edge parts of the 1st concrete 22 (1st floor part 12) of the 1st cross direction X. That is, each of the first reinforcing bars 25 has a first end portion in the first intersecting direction X of the first concrete 22 and a second end portion opposite to the first end portion in the first intersecting direction X of the first concrete 22. , Extending over. And each 1st rebar 25 applies the tensile force which acts between the 1st end part and 2nd end part of the 1st concrete 22 between the 1st end part and the 2nd end part of the 1st concrete 22. Communicate over. The plurality of first reinforcing bars 25 are arranged at intervals in the second intersecting direction Y.
Similarly, each second reinforcing bar 26 extends along the second intersecting direction Y. Each second reinforcing bar 26 transmits a tensile force between the ends of the first concrete 22 in the second intersecting direction Y. The plurality of second reinforcing bars 26 are arranged at intervals in the first intersecting direction X.
In the following, details of the configurations of the first reinforcing bar 25 and the second reinforcing bar 26 will be described by taking the first reinforcing bar 25 as an example.

The first rebar 25 is not particularly limited as long as it can transmit a tensile force between the ends of the first concrete 22 in the first cross direction X. The first reinforcing bar 25 may be formed of one reinforcing bar between the first end portion and the second end portion of the first concrete 22 in the first intersecting direction X, but may be configured as follows. Good. For the first reinforcing bar 25, round steel, deformed bar steel, welded gold steel, or the like is used.
As in the first modification shown in FIG. 3, the first reinforcing bar 25A may include reinforcing bar pieces 27a and 27b and a connecting reinforcing bar 27c that connects the ends of the reinforcing bar pieces 27a and 27b. The reinforcing bar pieces 27 a and 27 b and the connecting reinforcing bar 27 c are made of the same material as the first reinforcing bar 25.
The end of the reinforcing bar piece 27a and the first end of the connecting reinforcing bar 27c are joined by a welded portion 28 formed by welding. The welded portion 28 joins the end of the reinforcing bar piece 27b and the second end of the connecting reinforcing bar 27c opposite to the first end.

As in the second modification shown in FIG. 4, the first reinforcing bar 25B may include a reinforcing bar piece 27a and a reinforcing bar piece 27b. The end of the reinforcing bar piece 27a and the end of the reinforcing bar piece 27b are joined together by a welded portion 28.
As in the third modification shown in FIG. 5, the first reinforcing bar 25C may include reinforcing bar pieces 27a and 27b and a wire (wire) 29. The reinforcing bar piece 27a and the reinforcing bar piece 27b are connected by a number wire 29 in a state of being overlapped with each other by a predetermined required length. The reinforcing bar pieces 27a and the reinforcing bar pieces 27b are bonded to each other by bonding.
Like the 4th modification shown in Drawing 6, the 1st reinforcing bar 25D may be provided with reinforcing bar pieces 27a and 27b, and mechanical joint 30. The mechanical joint 30 is a coupling or the like. The mechanical joint 30 joins the reinforcing bar pieces 27a and 27b by sandwiching the ends of the reinforcing bar pieces 27a and 27b, respectively.
The second reinforcing bar 26 is configured similarly to the first reinforcing bar 25.

As shown in FIG. 7, a bent portion 25a bent downward may be formed at an end portion of the first reinforcing bar 25 in the first intersecting direction X. The bent portion 25a extends downward from the outside of the second reinforcing bar 26, which is arranged on the outermost side in the first intersecting direction X among the plurality of second reinforcing bars 26.
The number of the first reinforcing bars 25 included in the reinforcing bars 23 is not particularly limited and may be one. The number of the second reinforcing bars 26 included in the reinforcing bars 23 is not particularly limited and may be one.

In this example, as shown in FIG. 2, the first refractory coated beam 13A is an H-section steel 34A provided with a refractory coating 33A. A heat insulating material such as rock wool or glass wool is used for the fireproof coating 33A. The fireproof coating 33A is wound or sprayed on the outer surface of the H-section steel 34A. The fireproof coating 33A is formed by a spraying/painting method, a molding plate method, a winding method, or the like.
As shown in FIG. 1, the first refractory-covered beam 13A is arranged below the outer edge connecting the corners 12a and 12b of the first floor 12.
In addition, RC (Reinforced Concrete) and SRC (Steel Reinforced Concrete construction) may be used for the first refractory covered beam 13A.

The first refractory covered beam 13B is configured similarly to the first refractory covered beam 13A. The first refractory covered beams 13A and 13B extend along the first intersecting direction X and are arranged at intervals in the second intersecting direction Y. The first refractory covered beam 13B is arranged below the outer edge connecting the corners 12c and 12d of the first floor 12.
The second fireproof coated beams 14A and 14B are configured similarly to the first fireproof coated beam 13A. That is, the second fireproof coated beams 14A and 14B are provided with a fireproof coating. The second refractory-covered beams 14A and 14B respectively extend along the second intersecting direction Y and are arranged at intervals in the first intersecting direction X.
As shown in FIG. 2, both ends of the first fireproof covered beams 13A and 13B are joined to the second fireproof covered beams 14A and 14B, respectively. It should be noted that FIG. 2 shows only a part of the joined state of the first refractory coated beams 13A and 13B and the second refractory coated beams 14A and 14B.

Hereinafter, when the refractory covered beams 13A, 13B, 14A, and 14B are referred to without distinction, they are simply referred to as the refractory covered beams 13 and 14. As shown in FIG. 1, the refractory-covered beams 13 and 14 are formed in an annular shape (ring, square annular shape) that is a rectangular frame as a whole in a plan view. The fire-resistant coated beam may be formed in a plan view as a whole in an annular shape that is a polygonal frame, an annular shape (circular ring) that is a circular frame, or the like.
The fireproof coated beams 13 and 14 support the periphery of the first floor portion 12 from below over the entire circumference. The fireproof coated beams 13 and 14 may support a part of the periphery of the first floor 12 from below.
The first floor portion 12 is fixed to the fireproof covered beams 13 and 14 by studs 35 and the like provided on the upper surfaces of the fireproof covered beams 13 and 14 (see FIG. 2 ). Specifically, the stud 35 penetrates the first deck plate 21 and is embedded in the first concrete 22.

Here, the positional relationship between the ends of the first concrete 22 and the first rebar 25 in the first intersecting direction X and the second fireproof covered beam 14A will be described with reference to FIG. 7. The second fireproof coated beam 14A includes a fireproof coating 37A and an H-shaped steel 38A which are configured similarly to the fireproof coating 33A and the H-shaped steel 34A of the first fireproof coated beam 13A. The H-section steel 38A is configured by an upper flange 38Aa and a lower flange 38Ab being joined to each other via a web 38Ac.
Here, the edge of the upper flange 38Aa of the H-section steel 38A on the central portion side of the first floor portion 12 in plan view is referred to as an edge 38Aa1. An edge of the upper flange 38Aa opposite to the edge 38Aa1 is referred to as an edge 38Aa2. The center of the web 38Ac in the first intersecting direction X is referred to as a plate center 38Ac1.
For example, the end of the first concrete 22 in the first intersecting direction X coincides with the edge 38Aa2.
In the first intersecting direction X, the end of the first reinforcing bar 25 in the first intersecting direction X reaches the end edge 38Aa1 from the central portion side of the first floor portion 12 in plan view. It is more preferable that this end portion of the first reinforcing bar 25 reaches the plate center 38Ac1 in the first intersecting direction X.
The same applies to the end portion of the second reinforcing bar 26 in the second intersecting direction Y.

The reduced fireproof coated beam 15A is a beam having a reduced fireproof coating than the fireproof coated beams 13 and 14. The reduced fireproof coating beam 15A may be H-section steel that is not provided with a fireproof coating. Although the reduced fireproof coating beam 15A has a reduced amount of fireproof coating than the fireproof coated beams 13 and 14, it may be an H-shaped steel having some fireproof coating.
For example, the thickness of the fireproof coating such as rockwool on the fireproof coated beams 13 and 14 and the fireproof coated columns 16A and 16B can be determined by referring to "Blown Rockwool Coated Fireproof Structure Construction Quality Control Guidelines (Rockwool Industry Association Spraying Section)". Set according to. When the fireproof coated beams 13, 14 and the like are required to be fireproof for one hour, the thickness of the fireproof coating is set to 25 mm. Similarly, when the fireproof coated beams 13, 14 and the like are required to be fireproof for 2 hours, the thickness of the fireproof coating is set to 45 mm. When the fireproof coated beams 13, 14 and the like are required to be fireproof for 3 hours, the thickness of the fireproof coating is set to 65 mm. In the present specification, a beam or column provided with a fireproof coating means, for example, a beam or column provided with a fireproof coating of this specification.
In this case, the thickness of the fireproof coating on the reduced fireproof coated beam 15A is set to about 1/10 to 1/2 of the thickness of the fireproof coating on the fireproof coated beams 13 and 14 according to the respective fireproof performance.

The reduced fire resistant coated beams 15B and 15C have the same configuration as the reduced fire resistant coated beam 15A. Hereinafter, when the reduced fireproof coated beams 15A, 15B, and 15C are not distinguished, they are abbreviated as the reduced fireproof coated beams 15. The same applies to the fireproof coated columns 16A and 16B.
As shown in FIG. 1, the reduced fireproof coated beam 15 is arranged in a region R1 surrounded by annular fireproof coated beams 13 and 14. The reduced fireproof coated beam 15 extends along the first intersecting direction X between the first fireproof coated beam 13A and the first fireproof coated beam 13B. The reduced fire resistant coated beams 15 are arranged at intervals in the second cross direction Y. Both ends of the reduced fireproof coated beam 15 are joined to the second fireproof coated beams 14A and 14B, respectively.
The reduced fireproof coating beam 15 supports the central portion and the like of the first floor portion 12 in plan view from below.

A steel column (H-shaped steel, cross steel frame, square steel pipe, circular steel pipe, etc.) provided with a fireproof coating is used for the fireproof coated column 16A. In addition, RC, SRC, and CFT (Concrete Filled steel Tube) may be used for the fireproof coated column 16A.
The fireproof coated pillar 16B is configured similarly to the fireproof covered pillar 16A. Hereinafter, when the refractory-coated pillars 16A and 16B are not distinguished, they are simply referred to as the refractory-covered pillars 16.
The fireproof coated pillars 16 extend in the vertical direction Z, respectively. The upper end portion of the fireproof covered column 16A is joined to the joint portion between the first fireproof covered beam 13B and the second fireproof covered beam 14A and the corner portion 12c of the first floor portion 12, respectively. The upper end of the fireproof coated pillar 16B is joined to the joint between the first fireproof covered beam 13B and the second fireproof covered beam 14B and the corner 12d of the first floor portion 12, respectively.
The corners 12a and 12b of the first floor portion 12 are not directly supported by the columns (including the fireproof coated columns and the reduced fireproof coated columns). Here, the fact that the corner portion 12a is not directly supported by the pillar means that the corner portion 12a is not supported by the pillar without going through the beam. Specifically, it means that the pillar is not disposed below the corner 12a and the corner 12a and the pillar are not in contact with each other. However, the fact that the corner 12a is not directly supported by the column does not mean that the corner 12a is supported by the column via the beam. The same applies to the corner 12b.

Hereinafter, the corner 12a is also referred to as a combined corner 12a, and the corner 12b is also referred to as a combined corner 12b. The connecting corners 12a and 12b are two of the plurality of corners 12a to 12d of the first floor 12.
The connecting corners 12a and 12b may be supported from below by a reduced fireproof coated column having a reduced amount of fireproof coating than the fireproof coated column. The corners of the first floor 12 that are not directly supported by the pillars are the corners 12a and 12b, but may be one of the corners 12a to 12d, or the corners 12a to 12d. It may be three or four.

The extension beam 17A is configured similarly to the first refractory covered beam 13A. Although not shown, for example, the extension beam 17A is H-section steel with a fireproof coating. The extension beam 17A extends along the second intersecting direction Y. The first end portion of the extension beam 17A is joined (joined) to a portion where the first refractory-covered beam 13A and the second refractory-covered beam 14A are joined, and to a joining corner portion 12a of the first floor portion 12, respectively. . The extension beam 17A extends in a direction away from the second refractory-covered beam 14A starting from the joint corner 12a.
The extension beam 17A is integrated with the second refractory-covered beam 14A to form a connected refractory-covered beam 39A.
In addition, in this embodiment, the extension beam 17A and the second refractory-covered beam 14A are integrally formed as a connected refractory-covered beam 39A which is one refractory-covered beam. However, for ease of explanation, the portion supporting the first floor portion 12 is treated as the second refractory-covered beam 14A, and the portion not supporting the first floor portion 12 is treated as the extension beam 17A.

The extension beam 17B is configured similarly to the extension beam 17A. The extension beam 17B extends along the second intersecting direction Y. The first end portion of the extension beam 17B is connected to a portion where the first refractory-covered beam 13A and the second refractory-covered beam 14B are joined, and to a joining corner portion 12b of the first floor portion 12, respectively.
The extension beam 17B is integrated with the second refractory-covered beam 14B to form a joint refractory-covered beam 39B.

The fireproof coated column 18A is configured similarly to the fireproof coated column 16A. Although not shown, for example, the refractory-coated column 18A is H-section steel with a refractory coating. The upper end portion of the fireproof coated column 18A is joined to the second end portion (a portion different from the portion joined to the joining corner portion 12a) of the extension beam 17A, and supports the second end portion.
The fireproof coated column 18B is configured similarly to the fireproof coated column 18A. The fireproof coated column 18B is joined to a second end portion (a portion different from the portion joined to the joining corner portion 12b) of the extension beam 17B and supports the second end portion.
The fireproof coated column 18A may be joined to the central portion of the extension beam 17A in the longitudinal direction or the like. The same applies to the fireproof coated column 18B.

The support structure 41 includes a second floor 42 and a third fireproof covered beam 43.
The second floor 42 is configured similarly to the first floor 12. The second floor portion 42 is formed in a plate shape in which the vertical direction Z is the thickness direction. The second floor portion 42 is arranged side by side in the second intersecting direction Y with respect to the first floor portion 12. The second floor portion 42 is arranged on one side of the second floor portion 12 in the second intersecting direction Y.
The second floor portion 42 is integrated with the first floor portion 12 to form a floor (slab) 44. That is, the first floor portion 12 of the refractory structure 11 is a portion of the floor 44 partitioned into a rectangular shape. Floors 12 and 42 are a part of floor 44, which is partitioned from floor 44.
As shown in FIG. 2, the second floor portion 42 includes the first deck plate 21, the first concrete 22, and the second deck plate 46 and the second concrete that are configured similarly to the plurality of reinforcing bars 23 of the first floor portion 12. 47 and a plurality of reinforcing bars 48.
The second deck plate 46 is integrated with the first deck plate 21.
The second concrete 47 is integrated with the first concrete 22.
The plurality of rebars 48 includes a plurality of first rebars 25, a plurality of first rebars 50 having the same configuration as the plurality of second rebars 26, and a plurality of second rebars 51. The second reinforcing bar 51 is integrated with the second reinforcing bar 26.

The third refractory covered beam 43 is configured similarly to the first refractory covered beam 13A. The third refractory covered beam 43 extends along the first intersecting direction X. The third refractory covered beam 43 is joined to the second end of the extension beam 17A and the second end of the extension beam 17B, respectively.

The refractory structure 11 configured as described above has a heating curve (standard heating curve, standard heating temperature curve) defined by ISO 834-11:2014 (hereinafter abbreviated as ISO 834), as described later. When heated on the basis of the above, the maximum value of the bending of the first floor portion 12 in the desired heating time is less than the threshold value K(m) defined by the equation (6).
K=(L+1)/30 ··· (6)
However, L is the length (m) of the first floor portion 12 in the first intersecting direction X (first span). l is the length (m) of the first floor portion 12 in the second intersecting direction Y (second span). L and l are lengths of the first floor 12 in the direction along the flat surface 12e.
This threshold value K is the floor bending limit value described in Non-Patent Document 1 described above.
The first span is not limited to the length in the first intersecting direction X, and may be the length in the direction within the plane 12e of the first floor 12 (the direction along the plane 12e). The second span is not limited to the length in the second intersecting direction Y, and is a direction within the plane 12e of the first floor portion 12 as long as the length is in a direction orthogonal (crossing) to the first span. Good. The maximum value of the flexure of the first floor portion 12 is preferably less than the threshold value K obtained by the equation (6) regardless of the orientation of the first and second spans.

When the first floor is not rectangular in plan view, L is the length of the first span along the plane of the first floor, and l is along the plane of the floor and intersects the first span. It is the length of the second span. At this time, it is preferable to set the orientations of the first and second spans so that the threshold value K obtained by the equation (6) becomes smaller. By setting the threshold value K in this way, it is possible to evaluate the damage to the first floor 12 on the safe side.
The threshold value is not limited to this.

Next, a method for designing a refractory structure (hereinafter, also abbreviated as a design method) for designing the refractory structure 11 configured as described above will be described. FIG. 8 is a flowchart showing the design method S of this embodiment. This design method S is preferably used for, for example, a newly constructed refractory structure 11 and an existing refractory structure 11.
First, in the structure determining step (step S1 shown in FIG. 8 ), a publicly-known structure calculation is performed, so that as shown in FIG. The arrangement of columns 53 that support 52 is determined. The beam 52 is a beam obtained by removing the fireproof coating from the fireproof coated beams 13 and 14 and the reduced fireproof coated beam 15. The pillar 53 is a pillar obtained by removing the fireproof coating from the fireproof coated pillars 16A and 16B.
In the structure determining step S1, for example, the specifications and arrangement of the plurality of beams 52 and the plurality of columns 53 are determined based on the weight of the floor 44 and the load acting on the floor 44.
When the structure determining step S1 is completed, the process proceeds to step S3.

Next, in the fireproof specification determining step (step S3), when the first floor portion 12 is partitioned from the floor 44, the following settings are made. As shown in FIG. 10, the periphery of the first floor portion 12 partitioned from the floor 44 is set to be supported from below by the fire-resistant coated beams 13 and 14 in which the beam 52 is fire-resistant coated over the entire circumference. The structure 11 is designed. At this time, the fireproof structure 11 is designed by applying a fireproof coating to at least a part of the plurality of beams 52 so that the membrane effect by the first floor portion 12 is exhibited in the event of a fire. The membrane effect referred to here is the shape in which the floor on which a load acts in the event of a fire is bent so that the center of the floor becomes convex downward due to the fire-resistant coated beam and the tensile force transmission member. Means the effect of holding.
In this example, the beam 52 corresponding to the fireproof coated beams 13 and 14 and the column 53 corresponding to the fireproof coated columns 16A and 16B are provided with a fireproof coating to design the fireproof structure 11.
When the fireproof specification determining step S3 ends, the process proceeds to step S5.

Next, in the first supporting specification determining step (step S5), as shown in FIG. 1, the first ends of the extension beams 17A and 17B are joined to the joining corners 12a and 12b, and the first ends of the extension beams 17A and 17B are joined. The two end portions are set to be supported by the fireproof coated columns 18A and 18B.
When the first support specification determining step S5 is completed, the process proceeds to step S7.
Next, in the second support specification determining step (step S7), the joint corners 12a and 12b are set so as not to be directly supported by the columns or supported from below by the reduced fireproof coated columns. In this example, the connecting corners 12a and 12b are set so as not to be directly supported by the pillar. By setting the refractory structure 11 in this way, the pillar itself supporting the joint corners 12a and 12b from below is eliminated, and the fireproof coating of the pillar supporting the joint corners 12a and 12b from below is omitted.
In the second support specification determining step S7, the joint corners 12a and 12b are not directly supported by the pillars, but the joint corners 12a and 12b are not set to be supported from below by the reduced fireproof covering pillars. Good.
When the second supporting specification determining step S7 is completed, the process proceeds to step S9.

Next, in the determination step (step S9), when the refractory structure 11 is heated based on the heating curve defined by ISO 834, the maximum value of the flexure of the first floor portion 12 in a desired heating time is , Is smaller than the threshold value K defined by the equation (6) (smaller than the threshold value K) or the like. The determination step S9 is a step performed after the fireproof specification determination step S3, the first support specification determination step S5, and the second support specification determination step S7.
The desired heating time is, for example, 1 hour, 2 hours, or the like, based on the fire resistance performance specified by the Building Standards Act. Generally, the bending of the first floor portion 12 is maximum at the central portion of the first floor portion 12 in plan view. Whether or not the maximum value of the bending of the first floor portion 12 is less than the threshold value K can be determined by a known simulation.
Generally, when a building is heated by heat during a fire, the rigidity and proof stress of the reduced fireproof coated beam are considered to be zero. Therefore, at the time of fire, the first floor portion 12 is not supported by the reduced fireproof coated beam 15, but is supported by the fireproof coated beams 13 and 14.

When it is determined in the determination step S9 that the maximum value of the bending of the first floor portion 12 is not less than the threshold value K (NO), the process proceeds to the fireproof specification determination step S3.
On the other hand, when it is determined that the maximum value of the bending of the first floor portion 12 is less than the threshold value K (YES), all the steps of the design method S are completed. At this time, the refractory structure 11 is designed to the above-mentioned specifications.
The refractory structure 11 is a refractory structure designed by the design method S.

In the fireproof specification determining step S3 transferred from the determining step S9, at least a part of the plurality of beams 52 to be fireproof coated is changed so that at least one of the shape and the size of the first floor section partitioned from the floor 44 is changed. Do it. For example, the refractory structure 11A and the support structure 41 shown in FIG. 1 are modified by changing at least a part of the plurality of beams 52 that apply the fireproof coating to the refractory structure 11A and the support structure 41A shown in FIG. That is, a sufficient refractory coating is applied to the reduced fireproof coated beam 15A of the fireproof structure 11 shown in FIG. 1 to obtain the first fireproof coated beam 13A of the fireproof structure 11A shown in FIG. The first refractory-covered beam 13A of the refractory structure 11 shown in FIG. 1 is reduced to the first refractory-covered beam 54 of the support structure 41A as shown in FIG.
The first floor portion 12A of the refractory structure 11A shown in FIG. 11 has a shorter length in the second intersecting direction Y than the first floor portion 12 of the refractory structure 11 shown in FIG. Similarly, the lengths of the refractory covered beams 14A and 14B in the second intersecting direction Y are shortened. The shape of the first floor portion 12A is changed to a shape close to a square in a plan view with respect to the first floor portion 12.

Changing the size of the first floor means, for example, keeping the shape similar to the original first floor without changing the shape of the first floor that is rectangular in plan view. It means increasing or decreasing the size.
Further, after performing the first supporting specification determining step S5 and the second supporting specification determining step S7, the determining step S9 is performed.

Generally, as the first floor portion 12A becomes smaller, the maximum value of the bending of the first floor portion 12A also becomes smaller. Although the floor flexure limit value described in Non-Patent Document 1 is also small, the extent that the floor flexure limit value is small is smaller than the extent that the maximum flexure value of the first floor portion 12A is small. For this reason, the maximum value of the bending of the first floor portion 12A tends to be less than the floor bending limit value (threshold value).
In this way, the fireproof specification determining step S3, the first supporting specification determining step S5, and the second supporting specification determining step S7 are repeatedly performed as a set until a determination of YES is made in the determination step S9, and a plurality of fireproof coatings are applied. Adjust beam 52.

In this design method S, after the structure determining step S1, the fireproof specification determining step S3, the first supporting specification determining step S5, and the second supporting specification determining step S7 are performed in this order. However, the order of performing the fireproof specification determining step S3, the first support specification determining step S5, and the second support specification determining step S7 after the structure determining step S1 is not particularly limited. For example, after the structure determining step S1, the second supporting specification determining step S7, the first supporting specification determining step S5, and the fireproof specification determining step S3 may be performed in this order.

Here, the manner in which the first floor portion 12 and the like bend due to the membrane effect before and after a fire will be schematically described.
FIG. 12 shows an exploded perspective view of the refractory structure 11 in a normal state where no fire has occurred. Note that, in FIG. 12 and FIG. 13 described later, the refractory structure 11 is shown in a simplified manner. Specifically, the reduced fireproof coated beam 15, the extension beams 17A and 17B, and the fireproof coated columns 18A and 18B of the fireproof structure 11 are not shown.
In the normal state shown in FIG. 12, a downward external force F1 acts on the first floor 12, the reduced fireproof coated beam 15A, etc. due to gravity, static load, etc. acting on the first floor 12, the reduced fireproof coated beam 15A, etc.
On the other hand, at the time of fire, as shown in FIG. 13, the center portion of the first floor portion 12 in plan view bends downward to be convex. However, due to the so-called membrane effect, the periphery of the first floor portion 12 is supported by the annular fireproof coated beams 13 and 14. The first reinforcing bars 25 extended by the bending of the first floor portion 12 transmit the tensile force F2 in the first intersecting direction X. The second reinforcing bars 26 extended by the bending of the first floor portion 12 transmit the tensile force F3 in the second intersecting direction Y. That is, the first floor portion 12 resists gravity or the like acting on the first floor portion 12 by the tensile forces F2 and F3.
Therefore, the central portion of the first floor portion 12 is supported by the fireproof covered beams 13, 14 and the reinforcing bars 25, 26 in the first intersecting direction X and the second intersecting direction Y, respectively.

At this time, the tension region R5 and the compression region R6 are formed on the first floor portion 12, respectively. The compression region R6 is shown with hatching in FIG. In the pulling region R5, the first floor 12 is pulled along the bent plane 12e. In the compression region R6, the first floor portion 12 is compressed along the bent flat surface 12e.
The tensile region R5 is formed in the central portion of the first floor portion 12 in plan view. The compression region R6 is formed around the tension region R5.

The membrane effect that occurs in the refractory structure 11 at the time of fire is an effect of resisting the tensile forces F2 and F3 by the reinforcing bar 23. On the other hand, in Patent Document 1, the robustness that occurs in the refractory structure at the time of fire is the effect of resisting the bending moment B1 by the concrete and the slab reinforcement.
As described above, the fire-resistant structure 11 of the present embodiment and the fire-resistant structure of Patent Document 1 have different effects that occur during a fire.

Next, a construction method (manufacturing method; hereinafter also abbreviated as construction method) of the refractory structure for constructing the refractory structure 11 will be described. FIG. 14: is a flowchart which shows the construction method S20 of this embodiment. While each step of the design method S is set but not actually executed, the difference is that each step of the installation method S20 is actually executed. This construction method S20 is preferably used, for example, for a new fireproof structure 11.
In this construction method S20, a pillar-beam construction step S21, a covering construction step S23, a first support step S25, and a second support step S27 are performed.
In the column-beam construction step S21, a floor 44, a plurality of beams 52 that support the floor 44 from below, and a column 53 that supports the plurality of beams 52 are constructed.
In the covering construction step S23, the beam 52 is subjected to a fireproof coating to form the fireproof coated beams 13 and 14, so that the periphery of the first floor portion 12 partitioned from the floor 44 is supported from below by the fireproof coated beams 13 and 14. .. In the coating construction step S23, a fire resistant coating is applied to the pillar 53 to form the fire resistant coated pillars 16A and 16B.
In the first supporting step S25, the first ends of the extension beams 17A and 17B are joined to the joining corners 12a and 12b, and the second ends of the extension beams 17A and 17B are supported by the fireproof coated columns 18A and 18B.
In the second supporting step S27, the joint corners 12a and 12b are not directly supported by the pillar. In addition, in the second supporting step S27, the joint corners 12a and 12b may be supported from below by the reduced fireproof coating column.
In the second supporting step S27, the joint corners 12a and 12b may not be directly supported by the columns, but the joint corners 12a and 12b may not be supported from below by the reduced fireproof coating columns.
With the above, all steps of the construction method S20 are completed, and the refractory structure 11 is constructed.

In the method for designing a refractory structure disclosed in Non-Patent Document 1, all the corners of the floor are designed to be supported by the refractory-coated columns. Therefore, those skilled in the art who have seen Non-Patent Document 1 design that all of the plurality of corners of the floor are supported by the fire-resistant coated columns.
All corners are supported by the refractory-covered columns, reducing corner design freedom.

On the other hand, according to the design method S of the present embodiment, by performing the structure determining step S1 and the fireproof specification determining step S3, the surroundings of the first floor portion 12 maintain constant rigidity and proof stress even in the event of a fire. It is set so as to be supported from below by the annular fireproof coated beams 13 and 14 that can be formed. The reinforcing bars 23 (first reinforcing bars 25 and second reinforcing bars 26) included in the first floor portion 12 are the tensile force F2 between the ends of the first floor portion 12 in the first intersecting direction X, and the first floor. The tensile force F3 between the ends of the portion 12 in the second cross direction Y is transmitted. At the time of fire, due to gravity or the like acting on the first floor portion 12, the center portion of the first floor portion 12 in a plan view is bent so as to be convex downward. However, the periphery of the first floor portion 12 is supported by the fireproof coated beams 13 and 14 due to the so-called membrane effect. Then, the reinforcing bars 23 extended by the bending of the first floor portion 12 transmit the tensile forces F2 and F3 in the first intersecting direction X and the second intersecting direction Y, respectively, so that the central portion of the first floor portion 12 is Supported. Therefore, the fireproof performance of the fireproof structure 11 can be set to be maintained at the same level as the conventional one. In addition, the fire resistance performance of the fire resistant structure 11 referred to here means to suppress the bending of the first floor portion 12 at the time of a fire and to prevent the external force from becoming larger than the bending resistance.

In the first support specification determining step S5, the connecting corners 12a, 12b are set to be supported by the fireproof coated columns 18A, 18B via the extension beams 17A, 17B. Further, in the second support specification determining step S7, the joint corners 12a and 12b are set so as not to be directly supported by the pillar. Therefore, it is possible to increase the degree of freedom in designing the joint corners 12a and 12b of the first floor portion 12 and to omit the fireproof coating of the columns supporting the joint corners 12a and 12b.
The omission of the fireproof coating of the pillar supporting the joint corners 12a and 12b means that the fireproof coating of the pillar is omitted by not directly supporting the joint corners 12a and 12b by the pillar, or the joint corner 12a is omitted. , 12b are supported by the reduced fireproof coated column, which means that the fireproof coating of the column is omitted.

Further, according to the construction method S20 of the present embodiment, by performing the column and beam construction step S21 and the covering construction step S23, the circumference of the first floor portion 12 is formed into an annular shape that can maintain constant rigidity and proof stress even in the event of a fire. It is supported from below by the fireproof coated beams 13 and 14. The reinforcing bar 23 included in the first floor portion 12 has a tensile force F2 between the end portions of the first floor portion 12 in the first intersecting direction X and an end portion of the first floor portion 12 in the second intersecting direction Y. The tensile force F3 between them is transmitted. At the time of fire, due to gravity or the like acting on the first floor portion 12, the center portion of the first floor portion 12 in a plan view is bent downward to be convex. However, due to the membrane effect, the periphery of the first floor portion 12 is supported by the fireproof coated beams 13 and 14. Then, the reinforcing bars 23 extended by the bending of the first floor portion 12 transmit the tensile forces F2 and F3 in the first intersecting direction X and the second intersecting direction Y, respectively, so that the central portion of the first floor portion 12 is Supported. Therefore, the fireproof performance of the fireproof structure 11 can be maintained at the same level as the conventional one.
In the first supporting step S25, the joint corners 12a, 12b are supported by the fireproof coated columns 18A, 18B via the extension beams 17A, 17B. Further, in the second supporting step S27, the joint corners 12a and 12b are not directly supported by the pillar. Therefore, it is possible to increase the degree of freedom in designing the joint corners 12a and 12b of the first floor portion 12 and to omit the fireproof coating of the columns supporting the joint corners 12a and 12b.

Further, according to the refractory structure 11 of the present embodiment, the periphery of the first floor portion 12 is supported from below by the annular refractory covered beams 13 and 14 that can maintain constant rigidity and proof strength even in the event of a fire. The reinforcing bar 23 included in the first floor portion 12 has a tensile force F2 between the end portions of the first floor portion 12 in the first intersecting direction X and an end portion of the first floor portion 12 in the second intersecting direction Y. The tensile force F2 between them is transmitted. At the time of fire, due to gravity or the like acting on the first floor portion 12, the center portion of the first floor portion 12 in a plan view is bent downward to be convex. However, due to the membrane effect, the periphery of the first floor portion 12 is supported by the fireproof coated beams 13 and 14. Then, the reinforcing bars 23 extended by the bending of the first floor portion 12 transmit the tensile forces F2 and F3 in the first intersecting direction X and the second intersecting direction Y, respectively, so that the central portion of the first floor portion 12 is Supported. Therefore, the fireproof performance of the fireproof structure 11 can be maintained at the same level as the conventional one.
In the fireproof structure 11, the joint corners 12a and 12b are supported by the fireproof coated columns 18A and 18B via the extension beams 17A and 17B. Moreover, the joint corners 12a, 12b are not directly supported by the columns. Therefore, it is possible to increase the degree of freedom in designing the joint corners 12a and 12b of the first floor portion 12 and to omit the fireproof coating of the columns supporting the joint corners 12a and 12b.

In the design method S, the determination step S9 is performed. Therefore, in the determination step S9, it is possible to determine whether the maximum value of the bending of the first floor portion 12 is less than the threshold value K.
When it is determined to be YES in the determination step S9, at least a part of the plurality of beams 52 to which the fireproof coating is applied is changed so that at least one of the shape and the size of the first floor section partitioned from the floor 44 is changed, The fireproof specification determining step S3 is performed, and then the determining step S9 is performed. Thereby, when the maximum value of the bending of the first floor portion 12 is not less than the threshold value K, at least one of the shape and the size of the first floor portion 12 partitioned from the floor 44 is adjusted, and in the determination step S9, It can be determined again whether the maximum value of the bending of the first floor portion 12 is less than the threshold value K.

The refractory structure 11 is designed by the design method S. Therefore, the refractory structure 11 can be designed by the design method S of the present embodiment. The design method S of the present embodiment is a method that can increase the degree of freedom in designing the corners 12a and 12b of the first floor 12 while maintaining fire resistance. And the design method S of this embodiment is a method which can omit at least one fireproof coating of the pillar which supports the corners 12a and 12b of the first floor 12 from below.
The refractory structure 11 is provided with a reduced fireproof coated beam 15. As a result, it is possible to prevent the first floor portion 12 from bending during normal times when no fire has occurred.
Since the first floor portion 12 is formed in a rectangular shape in plan view, it is possible to easily arrange the plurality of first floor portions 12 side by side in a compact manner.

The maximum value of the bending of the first floor portion 12 during the desired heating time is less than the threshold value K. Therefore, the membrane effect of the first floor portion 12 is effectively exhibited, and the first floor portion 12 can be made difficult to bend downward.
The reinforcing bar 23 includes a first reinforcing bar 25 and a second reinforcing bar 26. Therefore, with a simple structure of the first reinforcing bar 25 and the second reinforcing bar 26, the tensile force F2 between the ends of the first floor portion 12 in the first crossing direction X and the second crossing direction of the first floor portion 12 The tensile force F3 between the ends of Y can be transmitted respectively.

(simulation result)
Here, an example will be described in which the fire resistance performance of the refractory structure of the comparative example is evaluated by simulation, and the beams to which the fireproof coating is applied in the refractory structure of the comparative example are adjusted to form the refractory structure of the example.
FIG. 15 shows a building 1B in which the refractory structure 11B of the comparative example is used. The building 1B includes a refractory structure 11B and a support structure 41B.
The refractory structure 11B includes, in addition to the components of the refractory structure 11 of the first embodiment, a reduced fire resistant coated beam 15D and fire resistant coated columns 16C and 16D.

FIG. 16 shows a vertical cross-sectional view of the first floor portion 12 of the refractory structure 11B used in the simulation.
The distance from the upper end of the reinforcing bar 23 to the upper surface of the first concrete 22 (the cover thickness of the first concrete 22 with respect to the reinforcing bar 23) was set to 30 mm. The thickness of the first floor portion 12 was 200 mm.
The design standard strength Fc of the first concrete 22 was set to 40 N/mm ² (Newton per square millimeter). As the reinforcing bars 23 (first reinforcing bars 25 and second reinforcing bars 26), reinforcing bars having a nominal diameter D10 and a tensile strength of 500 MPa were arranged at a pitch of 100 mm.

As shown in FIG. 15, the reduced fire resistant coated beam 15D has the same configuration as the reduced fire resistant coated beam 15A. The reduced fire resistant coated beam 15D extends along the first intersecting direction X and is arranged between the first fire resistant coated beam 13B and the reduced fire resistant coated beam 15C. Both ends of the reduced fireproof coated beam 15D are respectively joined to the second fireproof coated beams 14A and 14B.
The fireproof coated columns 16C and 16D have the same configuration as the fireproof coated column 16A. The upper end of the fireproof coated pillar 16C is joined to the joint between the first fireproof covered beam 13A and the second fireproof covered beam 14A and the corner 12a of the first floor portion 12, respectively. The upper end of the fireproof coated pillar 16D is joined to the joint between the first fireproof covered beam 13A and the second fireproof covered beam 14B and the corner 12b of the first floor portion 12, respectively.
In the fire resistant structure 11B of the comparative example, all of the corners 12a, 12b, 12c, 12d of the first floor 12 are supported from below by the fire resistant coated columns 16C, 16D, 16A, 16B, respectively.

The support structure 41B includes, in addition to the respective components of the support structure 41 of the first embodiment, first reduced fire resistant coated beams 54A, 54B, 54C, 54D.
The first reduced fire resistant coated beam 54 is configured similarly to the reduced fire resistant coated beam 15A. The first reduced fire-resistant coated beams 54 extend along the first intersecting direction X between the third fire-resistant coated beam 43 and the first fire-resistant coated beam 13A and are spaced from each other in the second intersecting direction Y. Has been done. Both ends of the first reduced fire resistant coating beam 54 are joined to the extension beams 17A and 17B, respectively.

The fire-resistant coated beam 14 and the extension beam 17, which are the primary beams, were made of H-section steel (800×250×12×22, made of S355) with fire-resistant coating. As the refractory-coated beams 13 and 43 as the secondary beams, H-section steel (600×200×9×12, made of S355) on which a fireproof coating was applied was used.
H-section steel (600×200×9×12, made from S355) was used as the secondary beam 15 and the first reduced fireproof coated beam 54 which are secondary beams. The reduced fireproof coated beam 15 and the first reduced fireproof coated beam 54 are provided with a fireproof coating according to the fireproof specifications.
The length of the refractory structure 11B in the first cross direction X and the length in the second cross direction Y were each 15,000 mm. The length of the support structure 41B in the first cross direction X and the length of the second cross direction Y were each 15,000 mm.
The load conditions were a fixed load (Dead Load) of 1.5 kPa (kilopascal) and a loading load (Live Load) of 3.0 kPa.

17 to 20 show simulation results of the temperature and stress of the building 1B when the building 1B is heated based on the heating curve defined in ISO 834.
In the simulation, the building 1B supported under a predetermined constraint condition is heated by a fire or the like, so that the temperature of the building 1B rises. The building 1B whose temperature has risen expands and its rigidity and proof stress decrease. Stress is generated in the building 1B according to the constraint condition. At the time of fire, the fire-resistant coated columns 16, 18, the fire-resistant coated beams 13, 14, 43, the extension beam 17, and the reinforcing bar 23 generate predetermined rigidity and proof strength, but the reduced fire-resistant coated beams 15, 54 lose their rigidity and proof strength. Think

FIG. 17 shows a change in temperature of each portion of the refractory structure 11B with respect to time in the refractory structure 11B of the comparative example. In FIG. 17, the horizontal axis represents time (minutes) and the vertical axis represents temperature (° C.). A solid line L1 represents the simulation result of the reduced fireproof coating beam 15A to which the fireproof coating is not applied. The dotted line L2 represents the simulation result on the lower surface of the first floor 12, the dashed line L3 represents the simulation result on the upper surface of the first floor 12, and the dashed double-dotted line L4 represents the simulation result on the reinforcing bar 23. Represent
During 120 minutes after starting heating, the temperatures of the reduced fire resistant coated beam 15A, the lower surface and the upper surface of the first floor portion 12, and the reinforcing bars 23 increase with the lapse of time. The temperature of each part is highest in the reduced fireproof coated beam 15A, and decreases in the order of the lower surface of the first floor portion 12, the reinforcing bar 23, and the upper surface of the first floor portion 12.

FIG. 18 shows a change in the maximum value of the bending of the first floor portion 12 with respect to time in the fireproof structure 11B of the comparative example. In FIG. 18, the horizontal axis represents time (minutes), and the vertical axis represents the maximum value (mm) of bending of the first floor portion 12. The solid line L7 represents the simulation result of the maximum value of the bending of the first floor portion 12. A dotted line L8 represents the deflection limit value of the first floor portion 12 according to the expression of {(L+1)/30} of Non-Patent Document 1 described above. It should be noted that at the time t1 (about 40 minutes after) when the maximum value of the bending of the first floor 12 reaches the bending limit value, the maximum value of the bending of the first floor 12 is prevented from further increasing so as not to increase. The calculation of the deflection of the portion 12 is terminated. If the calculation of the bending of the first floor portion 12 is not terminated at the time t1, the maximum value of the bending of the first floor portion 12 increases as indicated by a dashed line L9.
In the refractory structure 11B of the comparative example, the maximum value of the bending of the first floor portion 12 reached the bending limit value at the time t1, so the first floor portion 12 is held without collapsing at least until the time t1. I found out.

FIG. 19 shows changes in bending proof strength with respect to time in the refractory structure 11B of the comparative example. In FIG. 19, the horizontal axis represents time (minutes) and the vertical axis represents bending yield strength (kN/m ² ). A dotted line L13 represents the bending proof simulation result of the first refractory covered beam 13A. A dashed line L14 represents a simulation result of bending strength of the first floor portion 12, and a solid line L12 represents a simulation result of the bending resistance of the first fireproof covered beam 13A and the first floor portion 12 as a whole. A dotted line L15 represents the external force acting on the load.
With the passage of time, the temperature of the first refractory-covered beam 13A increases, and the bending resistance of the first refractory-covered beam 13A decreases. On the other hand, the bending strength of the first floor portion 12 increases as the temperature rises. The bending strength of the first refractory-covered beam 13A and the first floor portion 12 as a whole becomes substantially smaller with the passage of time.
If the bending proof stress represented by the line L12 is larger than the external force represented by the line L15, the first floor portion 12 can support the load.

FIG. 20 shows a change in value of (external force/bending proof strength (as a whole of the first fireproof coated beam 13A and the first floor portion 12)) with respect to time in the fireproof structure 11B of the comparative example. 20, the horizontal axis represents time (minutes) and the vertical axis represents the value of (external force/bending strength). FIG. 20 is for clearly showing the magnitude relationship between the bending proof stress represented by the line L12 and the external force represented by the line L15 in FIG. A solid line L18 represents a value of (external force/bending strength), and a dotted line L19 represents a line having a value of (external force/bending strength) of 1.0.
With the passage of time, the value of (external force/bending strength) increases and approaches 1.0. However, since the value of (external force/bending proof strength) does not reach 1.0 even after 120 minutes have passed, it is clear that the first floor portion 12 can support the load even after 120 minutes have passed since the fire started. It was

As described above, in the refractory structure 11B of the comparative example, the first floor portion 12 does not collapse due to an external force larger than the bending resistance, and at least the maximum bending value reaches the bending limit value. It was found that the floor 12 was retained without collapsing.
In the determining step S9 of the design method S described above, when the maximum value of the bending of the first floor portion 12 is less than the threshold value and the external force acting on the refractory structure 11 is smaller than the bending proof strength, YES is determined. It may be determined. When YES is determined in the determination step S9, all steps of the design method S are completed.

FIG. 21 shows a building 1C in which the refractory structure 11C of the example is used. The building 1C includes a refractory structure 11C and support structures 41C and 41D.
The refractory structure 11C is provided with extension beams 58A, 58B and fireproof coated columns 59A, 59B in place of the reduced fireproof coated beam 15D and the fireproof coated columns 16C, 16D with respect to the refractory structure 11B.
In the first floor 12 of the refractory structure 11C, in addition to the corners 12a and 12b being the joint corners 12a and 12b among the corners 12a to 12d, the corners 12c and 12d are also joint corners 12c and 12d. Is. That is, the fireproof coated column 16 is not joined to any of the joint corners 12a to 12d.
The extension beams 58A and 58B are configured similarly to the extension beam 17A. The extension beams 58A and 58B extend along the second intersecting direction Y.
The first end portion of the extension beam 58A is connected to a portion where the first refractory-covered beam 13B and the second refractory-covered beam 14A are joined, and to a joint corner 12c of the first floor portion 12, respectively. The extension beam 58A extends in a direction away from the second refractory-covered beam 14A, starting from the joint corner 12c. The 1st end part of the extension beam 58B is each couple|bonded with the part which the 1st refractory coating beam 13B and the 2nd refractory coating beam 14B were joined, and the joint corner part 12d of the 1st floor 12. The extension beam 58B extends in a direction away from the second refractory-covered beam 14B starting from the joint corner 12d.
The fireproof coated columns 59A and 59B are configured similarly to the fireproof coated column 18A. The upper end of the fireproof coated column 59A is joined to the second end of the extension beam 57A. The upper end of the fireproof coated column 59B is joined to the second end of the extension beam 57B.

The upper end of the fireproof covered pillar 16A is joined to the center of the second fireproof covered beam 14A in the second intersecting direction Y and the center of the corner 12a and the corner 12c of the first floor 12, respectively. The upper end of the fireproof covered pillar 16B is joined to the center of the second fireproof covered beam 14B in the second intersecting direction Y and the center of the corner 12b and the corner 12d of the first floor 12, respectively.

The support structure 41C does not include the first reduced fireproof coated beams 54C and 54D as compared with the support structure 41B.
The support structure 41D includes a third floor portion 61, a fourth fireproof coated beam 62, and second reduced fireproof coated beams 63A and 63B. The third floor 61, the fourth fireproof covered beam 62, and the second reduced fireproof covered beams 63A and 63B are the second floor 42 of the support structure 41C, the third fireproof covered beam 43, the first reduced fireproof covered beam 54A, 54B and the like respectively.

In the building 1C, the second floor portion 42 and the third floor portion 61 of the support structures 41C and 41D are arranged on both sides of the fire resistant structure 11C in the second intersecting direction Y with respect to the first floor portion 12.
The length of the building 1C in the first intersecting direction X and the length of the building 1B in the first intersecting direction X are equal to each other. The length of the building 1C in the second intersecting direction Y and the length of the building 1B in the second intersecting direction Y are equal to each other.
The building 1C is a building that is configured by reducing the fireproof coating of the first fireproof coated beam 13A or applying a fireproof coating to the reduced fireproof coated beam 15B and the first reduced fireproof coated beam 54C in the building 1B. is there.

22 to 25 show simulation results of the temperature and stress of the building 1C when the building 1C is heated based on the heating curve defined in ISO 834.
FIG. 22 shows a change in temperature of each portion with respect to time in the refractory structure 11C of the example. 22, the horizontal axis represents time (minutes) and the vertical axis represents temperature (° C.). A solid line L21 represents a simulation result of the reduced fireproof coating beam 15A to which the fireproof coating is not applied. The dotted line L22 represents the simulation result on the lower surface of the first floor 12, the dashed line L23 represents the simulation result on the upper surface of the first floor 12, and the dashed double-dotted line L24 represents the simulation result on the reinforcing bar 23. Represent
The temperature changes in the first refractory-covered beam 13A, the lower surface, the upper surface of the first floor portion 12 and the reinforcing bars 23 in the refractory structure 11C of the example represented by the lines L21 to L24 are represented by the lines L1 to L4 in FIG. This is equivalent to the temperature changes in the first refractory-covered beam 13A, the lower surface, the upper surface of the first floor portion 12 and the reinforcing bars 23 in the refractory structure 11B of the comparative example.

FIG. 27 shows a change in the maximum value of the bending of the first floor portion 12 with respect to time in the refractory structure 11C of the example. In FIG. 23, the horizontal axis represents time (minutes) and the vertical axis represents the maximum value (mm) of bending of the first floor portion 12. The solid line L27 represents the simulation result of the maximum deflection of the first floor portion 12. The dotted line L28 represents the deflection limit value of the first floor portion 12 according to the expression of {(L+1)/30} of Non-Patent Document 1 described above. The length of the first floor portion 12 of the refractory structure 11C of the example in the second intersecting direction Y is shorter than the length of the first floor portion 12 of the refractory structure 11B of the comparative example in the second intersecting direction Y. Therefore, the deflection limit value of the first floor portion 12 represented by the line L28 is smaller than the deflection limit value of the first floor portion 12 represented by the line L8 in FIG. However, since the length of the first floor portion 12 of the fireproof structure 11C of the example in the second crossing direction Y is shorter than the length of the first floor portion 12 of the fireproof structure 11B of the comparative example in the second crossing direction Y. The maximum value of the bending of the first floor portion 12 becomes small.
In the refractory structure 11C of the example, the maximum value of the flexure of the first floor 12 does not reach the flexure limit value even after 120 minutes have elapsed from the occurrence of a fire due to the so-called membrane effect, and the first floor 12 receives a load. Found that it can support.

FIG. 24 shows a change in bending proof strength with respect to time in the refractory structure 11C of the example. In FIG. 24, the horizontal axis represents time (minutes) and the vertical axis represents bending yield strength (kN/m ² ). A dotted line L33 represents a simulation result of the bending strength of the first refractory covered beam 13A. A dashed line L34 represents the simulation result of the bending strength of the first floor portion 12, and a solid line L32 represents the simulation result of the bending resistance of the first refractory covered beam 13A and the first floor portion 12 as a whole. A dotted line L35 represents the external force that acts on the load.

FIG. 25 shows a change in the value of (external force/bending strength) with respect to time in the refractory structure 11C of the example. In FIG. 25, the horizontal axis represents time (minutes) and the vertical axis represents the value of (external force/bending strength). FIG. 25 is for clearly showing the magnitude relationship between the bending proof stress represented by the line L32 and the external force represented by the line L35 in FIG. A solid line L38 represents a value of (external force/bending strength), and a dotted line L39 represents a line having a value of (external force/bending strength) of 1.0.
With the passage of time, the value of (external force/bending strength) increases and approaches 1.0. However, since the value of (external force/bending strength) does not reach 1.0 even after 120 minutes have passed, the first floor portion 12 can support the load even after 120 minutes have elapsed from the occurrence of the fire. I knew I could do it.
Further, the value of (external force/bending strength) in the refractory structure 11C of Example is asymptotically smaller than the value of (external force/bending strength) in the refractory structure 11B of Comparative Example is asymptotic, It was found that the refractory structure 11C of No. 2 has a sufficient bending resistance.

As described above, in the refractory structure 11C of the example, the maximum value of the bending of the first floor portion 12 does not reach the bending limit value, and the external force is smaller than the bending proof stress. It turns out that I can support.
In a building 1B including a fire resistant structure 11B of a comparative example, applying a fire resistant coating to the first fire resistant coated beam 13A, the reduced fire resistant coated beam 15, and the first reduced fire resistant coated beam 54, or reducing the fire resistant coating. Thus, the refractory structure 11C of the embodiment included in the building 1C can be obtained.

The structure of the fire resistant structure of the present embodiment can be variously modified as described below.
The building 2 shown in FIG. 26 includes a refractory structure 71 of the present embodiment and support structures 81A and 81B.
The refractory structure 71 does not include the refractory-coated columns 16A and 16B as compared with the refractory structure 11C of the embodiment.
The support structure 81A does not include the first reduced fireproof coated beams 54A and 54B as compared with the support structure 41C of the embodiment. The support structure 81B does not include the second reduced fireproof coated beams 63A and 63B, unlike the support structure 41D of the embodiment.

A building 2A shown in FIG. 27 includes a refractory structure 71A of the present embodiment and support structures 81A and 81B.
The refractory structure 71A includes refractory coated columns 16A and 16B in addition to the components of the refractory structure 71 of the modification.
The upper end of the fireproof covered pillar 16A is joined to the center of the second fireproof covered beam 14A in the second intersecting direction Y and the center of the corner 12a and the corner 12c of the first floor portion 12, respectively. The upper end of the fireproof covered pillar 16B is joined to the center of the second fireproof covered beam 14B in the second intersecting direction Y and the center of the corner 12b and the corner 12d of the first floor 12, respectively.

A building 2B shown in FIG. 28 includes a refractory structure 71B of this embodiment and support structures 81A and 81B.
The refractory structure 71B includes refractory-coated columns 16A, 16B, 16C, and 16D in addition to the components of the refractory structure 71 of the modification.
The upper end of the refractory-covered pillar 16A has an outer edge near the corner 12a between the corner 12a and the corner 12c of the first floor 12 and the joint between the second refractory-covered beam 14A and the reduced fire-resisting covered beam 15A. Are joined to each. The upper end of the fire-resistant covered pillar 16B has an outer edge near the corner 12b between the corner 12b and the corner 12d of the first floor 12 and the joint between the second fire-resistant covered beam 14B and the reduced fire-resistant covered beam 15A. Are joined to each.
The fireproof coated columns 16C and 16D have the same configuration as the fireproof coated column 16A. The upper end of the refractory-covered pillar 16C has an outer edge near the corner 12c between the joint between the second refractory-covered beam 14A and the reduced refractory-covered beam 15C and the corner 12a of the first floor 12 and the corner 12c. Are joined to each. The upper end of the fireproof covered pillar 16D has an outer edge near the corner 12d between the corner 12b and the corner 12d of the first floor 12 and the joint between the second fireproof covered beam 14B and the reduced fireproof covered beam 15C. Are joined to each.
Both ends of the second fireproof covered beams 14A and 14B are directly joined to the pair of first fireproof covered beams 13A and 13B. The second fireproof coated beams 14A and 14B are joined to the fireproof coated column 16.
The fireproof coated beams 13 and 14 are formed in a ring shape as a whole.

The fireproof coated columns 16A, 16B, 16C, 16D are arranged side by side in the first intersecting direction X, and are also arranged side by side in the second intersecting direction Y at the first pitch P1. The second refractory coated beams 14A and 14B are formed to have a length P2 longer than the first pitch P1. In this case, at least one of the corners 12a, 12b and the corners 12c, 12d projects outward in the second intersecting direction Y from the fireproof coated columns 16A, 16B, 16C, 16D. In this modification, all of the corners 12a, 12b and the corners 12c, 12d project outside the fireproof coated columns 16A, 16B, 16C, 16D in the second intersecting direction Y.
The second refractory covered beams 14A and 14B may be formed shorter than the first pitch P1.

According to the refractory structure 71B of the modified example, the periphery of the first floor 12 is supported from below by the annular refractory covered beams 13 and 14 that can maintain constant rigidity and proof strength even in the event of a fire. The reinforcing bar 23 included in the first floor portion 12 has a tensile force F2 between the end portions of the first floor portion 12 in the first intersecting direction X and an end portion of the first floor portion 12 in the second intersecting direction Y. The tensile force F3 between them is transmitted. At the time of fire, due to gravity or the like acting on the first floor portion 12, the center portion of the first floor portion 12 in a plan view is bent downward to be convex. However, due to the membrane effect, the periphery of the first floor portion 12 is supported by the fireproof coated beams 13 and 14. Then, the reinforcing bars 23 extended by the bending of the first floor portion 12 transmit the tensile forces F2 and F3 in the first intersecting direction X and the second intersecting direction Y, respectively, so that the central portion of the first floor portion 12 is Supported. Therefore, the fireproof performance of the fireproof structure 11 can be maintained at the same level as the conventional one.
In the refractory structure 71B, the joint corners 12a, 12b, 12c, 12d are supported by the refractory covered columns 18A, 18B, 59A, 59B via the extension beams 17A, 17B, 58A, 58B. Moreover, the joint corners 12a-12d are not directly supported by the columns. Therefore, the degree of freedom in designing the connection corners 12a to 12d of the first floor portion 12 can be increased, and the fireproof coating of the columns supporting the connection corners 12a to 12d can be omitted.

Since the second fireproof covered beams 14A, 14B are formed to have a length P2 longer than the first pitch P1, the end positions of the second fireproof covered beams 14A, 14B are located at the fireproof covered columns 16A, 16B, 16C, Forming a space below the corners 12a, 12b, 12c, 12d of the first floor 12 which is displaced in the second crossing direction Y with respect to the position of 16D and is supported by the ends of the second fireproof covered beams 14A, 14B. You can
The second intersecting direction Y may be a direction intersecting with the first intersecting direction X. In this case, for example, the first floor portion 12 is formed in a parallelogram shape (quadrangular shape) in a plan view.

Like the refractory structure 11 of the present embodiment and the refractory structures 71, 71A, 71B of the modified examples, the number of corners of the first floor 12 where the extension beam is not joined is particularly limited among the corners 12a to 12d. However, the number may be one or two or more.
Even with the refractory structures 71, 71A, 71B of the modified example, the degree of freedom of design in the corners of the first floor 12 is increased while maintaining the fire resistance, and the corners 12a to 12d of the first floor 12 are removed. At least one refractory coating on the supporting columns may be omitted.

(Second embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. 29 and FIGS. 8 and 14, but the same parts as those of the embodiment will be designated by the same reference numerals and the description thereof will be omitted. Only different points will be described.
As shown in FIG. 29, the building 4 includes the fire resistant structure 121 of the present embodiment and the support structure 41.
The refractory structure 121 includes first refractory coated columns 122A and 122B and second refractory coated columns (fireproof coated columns) instead of the fireproof coated columns 16A and 16B and the fireproof coated columns 18A and 18B of the fire resistant structure 11 of the first embodiment. Pillars) 123A and 123B are provided.
The first refractory covered columns 122A and 122B are configured similarly to the refractory covered columns 16A, but differ only in length from the refractory covered columns 16A. The first refractory covered columns 122A and 122B are longer than the refractory covered columns 16A.
Here, in the first fireproof coated column 122A, a portion (a part of itself) joined to the fireproof coated beams 13 and 14 is referred to as a column piece 122A1. Similarly, for the first fireproof coated column 122B, a portion joined to the fireproof coated beams 13 and 14 in the vertical direction Z is referred to as a column piece 122B1.

The first fireproof coated columns 122A and 122B support the fireproof coated beams 13 and 14. The fireproof coated beams 13 and 14 and the pillar pieces 122A1 and 122B1 are formed in an annular shape as a whole.
The second refractory covered pillars 123A and 123B are configured similarly to the first refractory covered pillar 122A. An intermediate portion of the second fireproof coated column 123A in the up-down direction Z is joined to the second end portion of the extension beam 17A and supports the second end portion. Similarly, an intermediate portion of the fireproof coated column 123B in the vertical direction Z is joined to the second end of the extension beam 17B and supports the second end.
The connecting corners 12a and 12b of the first floor 12 are not directly supported by the columns. The joint corners 12a and 12b may be supported from below by reduced fireproof coated columns having a reduced fireproof coating than the first fireproof coated columns 122A and 122B.

In this example, the fireproof coated beams 13 and 14 and the two pillar pieces 122A1 and 122B1 are formed in an annular shape as a whole. However, the number of fireproof coated beams and the number of column pieces formed in a ring shape as a whole is not particularly limited.

Next, a designing method for designing the refractory structure 121 configured as described above will be described. FIG. 8 is a flowchart showing the design method S30 of this embodiment. This design method S30 differs from the design method S of the first embodiment in that the fireproof specification determining step S31, the second support instead of the fireproof specification determining step S3, the second support specification determining step S7, and the determining step S9. The specification determining step S33 and the determining step S35 are performed.
In the fireproof specification determining step S31, the periphery of the first floor portion 12 partitioned from the floor 44 is set to be supported from below by the fireproof covered beams 13 and 14 and the pillar pieces 122A1 and 122B1.
In the second support specification determining step S33, the joint corners 12a and 12b are not directly supported by the pillars, or are supported from below by the reduced fireproof coated columns in which the fireproof coating is reduced as compared with the first fireproof coated columns 122A and 122B. Set to allow.
In the determining step S35, the fireproof specification determining step S31 is performed in such a manner that a plurality of beams to which the fireproof coating is applied and a plurality of beams to which the fireproof coating is applied are applied so that at least one of the shape and the size of the first floor section partitioned from the floor 44 is changed. Change at least a part of the pillar.

Next, a construction method for constructing the refractory structure 121 will be described. FIG. 14: is a flowchart which shows the construction method S40 of this embodiment. This construction method S40 differs from the construction method S20 of the first embodiment in that instead of the coating construction step S23, the first support step S25, and the second support step S27, the coating construction step S41 and the first support step S43. , And the second supporting step S45.
In the covering construction step S41, the beam 52 is provided with a fireproof coating to form the fireproof coated beams 13 and 14, and the column 53 is provided with a fireproof coating to form the first fireproof coated columns 122A and 122B. As a result, the periphery of the first floor portion 12 partitioned from the floor 44 is supported from below by the fireproof covered beams 13 and 14 and the pillar pieces 122A1 and 122B1.
In the first supporting step S43, the first ends of the extension beams 17A and 17B are joined to the joining corners 12a and 12b. Then, the second end portions of the extension beams 17A and 17B are supported by the second fireproof coated columns 123A and 123B.
In the second supporting step S45, the joint corners 12a and 12b are not directly supported by the pillar. In addition, in the second supporting step S45, the joint corners 12a and 12b may be supported from below by a reduced fireproof coated column having a reduced fireproof coating than the first fireproof coated columns 122A and 122B.

As described above, according to the designing method S30 of the present embodiment, by performing the structure determining step S1 and the fireproof specification determining step S31, the surroundings of the first floor portion 12 have a constant rigidity and yield strength even during a fire. It is set so that it can be maintained and is supported from below by the refractory covered beams 13 and 14 and the pillar pieces 122A1 and 122B1 which are formed in an annular shape as a whole. The reinforcing bars 23 included in the first floor portion 12 are the tensile force F2 between the end portions of the first floor portion 12 in the first cross direction X, and the end portions of the first floor portion 12 in the second cross direction Y. The tensile force F3 between them is transmitted. At the time of fire, due to gravity or the like acting on the first floor portion 12, the center portion of the first floor portion 12 in a plan view is bent so as to be convex downward. However, due to the membrane effect, the periphery of the first floor portion 12 is supported by the fireproof coated beams 13, 14 and the pillar pieces 122A1, 122B1. Then, the reinforcing bars 23 extended by the bending of the first floor portion 12 transmit the tensile forces F2 and F3 in the first intersecting direction X and the second intersecting direction Y, respectively, so that the central portion of the first floor portion 12 is Supported. Therefore, the fireproof performance of the fireproof structure 121 can be set to be maintained at the same level as the conventional one.

In the first support specification determining step S5, the joint corners 12a and 12b are set to be supported by the second refractory covered columns 123A and 123B via the extension beams 17A and 17B. Further, in the second support specification determining step S33, the joint corners 12a and 12b are set so as not to be directly supported by the pillar. Therefore, it is possible to increase the degree of freedom in designing the joint corners 12a and 12b of the first floor portion 12 and to omit the fireproof coating of the columns supporting the joint corners 12a and 12b.

Further, according to the construction method S40 of the present embodiment, by performing the column and beam construction step S21 and the covering construction step S41, it is possible to maintain constant rigidity and proof stress around the first floor portion 12 even in the event of a fire. It is supported from below by the fireproof coated beams 13 and 14 and the pillar pieces 122A1 and 122B1 formed in a ring shape. The reinforcing bar 23 included in the first floor portion 12 has a tensile force F2 between the end portions of the first floor portion 12 in the first intersecting direction X and an end portion of the first floor portion 12 in the second intersecting direction Y. The tensile force F3 between them is transmitted. At the time of fire, due to gravity or the like acting on the first floor portion 12, the center portion of the first floor portion 12 in a plan view is bent downward to be convex. However, due to the membrane effect, the periphery of the first floor portion 12 is supported by the fireproof coated beams 13, 14 and the pillar pieces 122A1, 122B1. Then, the reinforcing bars 23 extended by the bending of the first floor portion 12 transmit the tensile forces F2 and F3 in the first intersecting direction X and the second intersecting direction Y, respectively, so that the central portion of the first floor portion 12 is Supported. Therefore, the fireproof performance of the fireproof structure 121 can be maintained at the same level as the conventional one.
When the first supporting step S43 is performed, the joint corners 12a and 12b are supported by the second fireproof coated columns 123A and 123B via the extension beams 17A and 17B. Furthermore, when the second supporting step S45 is performed, the joint corners 12a and 12b are not directly supported by the pillar. Therefore, it is possible to increase the degree of freedom in designing the joint corners 12a and 12b of the first floor portion 12 and to omit the fireproof coating of the columns supporting the joint corners 12a and 12b.

Further, according to the fire resistant structure 121 of the present embodiment, the surroundings of the first floor portion 12 can maintain constant rigidity and proof stress even in the event of a fire, and the fire resistant coated beams 13, 14 formed in an annular shape as a whole and It is supported from below by the pillar pieces 122A1 and 122B1. The reinforcing bar 23 included in the first floor portion 12 has a tensile force F2 between the end portions of the first floor portion 12 in the first intersecting direction X and an end portion of the first floor portion 12 in the second intersecting direction Y. The tensile force F2 between them is transmitted. At the time of a fire, due to gravity or the like acting on the first floor portion 12, the central portion of the first floor portion 12 in a plan view is projected downward. However, due to the membrane effect, the periphery of the first floor portion 12 is supported by the fireproof coated beams 13, 14 and the pillar pieces 122A1, 122B1. Then, the reinforcing bars 23 extended by the bending of the first floor portion 12 transmit the tensile forces F2 and F3 in the first intersecting direction X and the second intersecting direction Y, respectively, so that the central portion of the first floor portion 12 is Supported. Therefore, the fireproof performance of the fireproof structure 121 can be maintained at the same level as the conventional one.
In the refractory structure 121, the joint corners 12a and 12b are supported by the second refractory-covered columns 123A and 123B via the extension beams 17A and 17B. Moreover, the joint corners 12a, 12b are not directly supported by the columns. Therefore, it is possible to increase the degree of freedom in designing the joint corners 12a and 12b of the first floor portion 12 and to omit the fireproof coating of the columns supporting the joint corners 12a and 12b.

In the design method S30, the determination step S35 is performed. Accordingly, in the determination step S35, it is possible to determine whether or not the maximum value of the bending of the first floor portion 12 is less than the threshold value K.
When it is determined to be YES in the determination step S35, at least a part of the plurality of beams 52 to which the fireproof coating is applied is changed so that at least one of the shape and the size of the first floor section partitioned from the floor 44 changes. The fireproof specification determining step S31 is performed, and then the determining step S35 is performed. Thereby, when the maximum value of the bending of the first floor portion 12 is not less than the threshold value K, at least one of the shape and the size of the first floor portion 12 partitioned from the floor 44 is adjusted, and in the determination step S35, It can be determined again whether the maximum value of the bending of the first floor portion 12 is less than the threshold value K.

(Third Embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. 30, but the same parts as those of the above-mentioned embodiment are designated by the same reference numerals, and the description thereof will be omitted. Only different points will be described.
As shown in FIG. 30, the fire- resistant structures 91A, 91B, 91C of the present embodiment are used in this building 3. In addition, in FIG. 30, the fire-resistant coated beam 94 and the reduced fire-resistant coated beam 95, which will be described later, are shown transparently, and the floor portions 96a, 96b, 96c included in the fire- resistant structures 91A, 91B, 91C are hatched. .
The building 3 includes a plurality of fireproof coated columns 93 arranged in a grid pattern in a plan view. The plurality of fireproof coated columns 93 are arranged side by side in the first intersecting direction X and the second intersecting direction Y, respectively.
A plurality of fireproof covered beams 94 are joined to the plurality of fireproof covered columns 93, and a reduced fireproof covered beam 95 is joined to the plurality of fireproof covered beams 94.

A floor 96 is supported on the plurality of fireproof coated beams 94 and reduced fireproof coated beams 95.
A core wall 99 is arranged at the center of the building 3 in a plan view, and stairs 100 are arranged at the outer edge of the building 3.
The refractory structure 91A includes a floor portion 96a that is a part of the floor 96. The floor portion 96a is formed in a rectangular shape having a plurality of corners in a plan view. The fireproof coated column 93 is not joined to any corner of the floor 96a.
Of the four corners of the floor portion 96b included in the fireproof structure 91B, the fireproof coated columns 93 are joined to two corners. Of the four corners of the floor portion 96c included in the fireproof structure 91C, the fireproof coated columns 93 are joined to two corners.

According to the fire resistant structures 91A, 91B, 91C of the present embodiment, while maintaining the fire resistant performance, the degree of freedom of design in the corners of the floor portions 96a, 96b, 96c is increased, and the floor portions 96a, 96b, 96c are improved. At least one refractory coating on the pillar supporting the plurality of corners may be omitted. Then, the degree of freedom in arranging the fireproof structures 91A, 91B, 91C in the building 3 can be increased.

As described above, the first to third embodiments of the present invention have been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and a configuration within a range not departing from the gist of the present invention Change, combination, deletion, etc. are also included. Further, it goes without saying that the configurations shown in the respective embodiments can be appropriately combined and used.
For example, in the design methods S and S30 of the first and second embodiments, the determination step S9 need not be performed. The maximum value of the bending of the first floor portion during the desired heating time of the refractory structure may be the threshold value K or more.

In the first to third embodiments, the fireproof coated beams 13 and 14 may not include the stud 35. That is, the periphery of the first floor portion 12 may be supported from below by the fireproof covered beams 13 and 14, or may be supported from below by the fireproof covered beams 13 and 14 and the pillar pieces 122A1 and 122B1.
The first floor portion may have a polygonal shape such as a triangular shape or a pentagonal shape in a plan view. The fireproof coated beams 13 and 14 may be formed in an annular shape or the like in plan view as a whole. The refractory structure may not include the reduced fire resistant coated beam.

The design method of the refractory structure, the construction method of the refractory structure, and the refractory structure of the present disclosure increase the degree of freedom of design in the corner portion of the floor while maintaining the fire resistance performance, and the plurality of corners of the floor portion. It can be suitably used as a refractory structure capable of omitting at least one refractory coating of a column supporting a part, and a designing method and a construction method thereof.

11, 11A, 11C, 71, 71A, 71B, 91A, 91B, 91C, 121 Fire- resistant structure 12, 12A 1st floor (floor)
12a, 12b corners (joint corners)
12c, 12d Corner part 12e Plane 13A, 13B 1st fireproof coated beam (fireproof coated beam)
14A, 14B Second fireproof coated beam (fireproof coated beam)
15A, 15B, 15C, 95 Reduced fireproof coated beams 16A, 16B, 16C, 16D, 93 Fireproof coated columns 17A, 17B Extension beams 18A, 18B Fireproof coated columns 21 First deck plate (tensile force transmitting member)
23 Reinforcing bar (tensile force transmitting member)
44 floor (slab)
45A, 45B 1st fireproof coated column (fireproof coated column)
52 Beams 53 Pillars 59A, 59B Second fireproof coated pillars (fireproof coated pillars)
94 Fireproof Covered Beams 96a, 96b, 96c Floors 122A, 122B First Fireproof Covered Columns 122A1, 122B1 Column Pieces (Part of Their Own)
123A, 123B 2nd fireproof coating pillar F2, F3 Tensile force S, S30 Design method (design method of fireproof structure)
S1 Structure determination step S3, S31 Fireproof specification determination step S5 First support specification determination step S7, S33 Second support specification determination step S9, S35 Judgment step S20, S40 Construction method (construction method of fireproof structure)
S21 Column beam construction process S23, S41 Covering construction process S25, S43 First support process S27, S45 Second support process X First cross direction Y Second cross direction

Claims (16)

1. In a slab including a tensile force transmission member, a floor section partitioned into a polygonal shape having a plurality of corners in a plan view,
   A fireproof coating is applied, and an annular fireproof beam that supports the periphery of the floor from below,
   An extension beam having a fireproof coating and coupled to a coupling corner that is at least one of the plurality of corners of the floor;
   A fireproof coated column, which is provided with a fireproof coating and supports a portion different from the portion connected to the connection corner of the extension beam,
   Equipped with
   When the directions intersecting with each other in the plane of the floor are the first intersecting direction and the second intersecting direction, the tensile force transmitting member includes a tensile force between end portions of the floor in the first intersecting direction, And a method for designing a refractory structure for designing a refractory structure that respectively transmits a tensile force between the ends of the floor portion in the second intersecting direction,
   By performing a structural calculation, the slab, a plurality of beams that support the slab from below, and a structure determination step of determining the arrangement of columns that support the plurality of beams,
   Around the floor section partitioned from the slab, a refractory specification determining step of setting so as to be supported from below by the refractory coated beam having a fireproof coating on the beam,
   A first support specification determining step of connecting the extension beam to the connection corner, and setting a part of the extension beam different from the part connected to the connection corner to be supported by the refractory-coated column;
   A second support specification determining step of setting the joint corner not to be directly supported by a column or to be supported from below by a reduced fireproof coated column in which the fireproof coating is reduced compared to the fireproof coated column;
   Method for designing fireproof structure.
2. After the fireproof specification determining step, the first support specification determining step, and the second support specification determining step,
   When the refractory structure is heated on the basis of the heating curve defined in ISO 834-11:2014, the maximum value of the flexure of the floor during a desired heating time is defined by the equation (1). The method for designing a refractory structure according to claim 1, wherein a determination step of determining whether or not it is less than the threshold value K is performed.
   K=(L+1)/30 ··· (1)
   Here, L is the length (m) of the first span along the plane of the floor, and l is the length (m of the second span along the plane of the floor and intersecting the first span. ).
3. In the determination step, when the maximum value of the bending of the floor is not less than the threshold value K,
   The fireproof specification determining step is performed by changing at least a part of the plurality of beams to which the fireproof coating is applied so that at least one of the shape and the size of the floor section partitioned from the slab changes.
   The method for designing a refractory structure according to claim 2, further comprising performing the determining step after performing the first supporting specification determining step and the second supporting specification determining step.
4. In a slab including a tensile force transmission member, a floor section partitioned into a polygonal shape having a plurality of corners in a plan view,
   A fireproof coated beam, which is provided with a fireproof coating and supports the periphery of the floor from below,
   A first refractory-covered column, which is provided with a refractory coating, supports the refractory-covered beam, and has a part of itself and the refractory-covered beam formed in an annular shape as a whole,
   An extension beam having a fireproof coating and coupled to a coupling corner that is at least one of the plurality of corners of the floor;
   A second refractory-coated column that is provided with a refractory coating and supports a portion of the extension beam that is different from the portion joined to the joining corner;
   Equipped with
   When the directions intersecting with each other in the plane of the floor are the first intersecting direction and the second intersecting direction, the tensile force transmitting member includes a tensile force between end portions of the floor in the first intersecting direction, And a method for designing a refractory structure for designing a refractory structure that respectively transmits a tensile force between the ends of the floor portion in the second intersecting direction,
   By performing a structural calculation, the slab, a plurality of beams that support the slab from below, and a structure determination step that determines the arrangement of a plurality of columns that support the plurality of beams,
   The periphery of the floor sectioned from the slab is supported from below by the fire-resistant coated beam having the beam applied with the fire-resistant coating, and the part of the first fire-resistant coated column having the fire-resistant coating applied to the column. And the fireproof specification determination process,
   A first supporting specification determining step of connecting the extension beam to the connection corner, and setting a portion of the extension beam different from the part connected to the connection corner to be supported by the second refractory-covered column; ,
   A second supporting specification determining step in which the joint corner is not directly supported by a pillar or is set to be supported from below by a reduced refractory coated pillar in which the refractory coating is reduced compared to the first refractory coated pillar; ,
   Method for designing fireproof structure.
5. After the fireproof specification determining step, the first support specification determining step, and the second support specification determining step,
   When the refractory structure is heated according to the heating curve defined in ISO 834-11:2014, the maximum value of the flexure of the floor during a desired heating time is defined by the equation (2). The method for designing a refractory structure according to claim 4, wherein a determination step of determining whether or not it is less than the threshold value K is performed.
   K=(L+1)/30 ··· (2)
   Here, L is the length (m) of the first span along the plane of the floor, and l is the length (m of the second span along the plane of the floor and intersecting the first span. ).
6. In the determination step, when the maximum value of the bending of the floor is not less than the threshold value K,
   In the fireproof specification determining step, at least one of the shape and the size of the floor section partitioned from the slab is changed, the plurality of beams to which the fireproof coating is applied, and the plurality of columns to which the fireproof coating is applied At least partly changed,
   The method for designing a refractory structure according to claim 5, further comprising performing the determining step after performing the first supporting specification determining step and the second supporting specification determining step.
7. A refractory structure designed by the method for designing a refractory structure according to any one of claims 1 to 6.
8. In a slab including a tensile force transmission member, a floor section partitioned into a polygonal shape having a plurality of corners in a plan view,
   A fireproof coating is applied, and an annular fireproof beam that supports the periphery of the floor from below,
   An extension beam having a fireproof coating and coupled to a coupling corner that is at least one of the plurality of corners of the floor;
   A fireproof coated column, which is provided with a fireproof coating and supports a portion different from the portion connected to the connection corner of the extension beam,
   Equipped with
   When the directions intersecting with each other in the plane of the floor are the first intersecting direction and the second intersecting direction, the tensile force transmitting member includes a tensile force between the ends of the floor in the first intersecting direction, And a method for constructing a refractory structure for constructing a refractory structure that transmits tensile forces between the ends of the floor portion in the second intersecting direction,
   A slab, a plurality of beams that support the slab from below, and a column-beam construction step that constructs a column that supports the plurality of beams,
   By applying a fireproof coating to the beam and the fireproof coated beam, a coating construction step of supporting the periphery of the floor section partitioned from the slab from below by the fireproof coated beam,
   A first supporting step in which the extension beam is coupled to the coupling corner, and a portion of the extension beam different from the portion coupled to the coupling corner is supported by the fireproof coated column;
   A second supporting step in which the joint corner is not directly supported by a pillar or is supported from below by a reduced fireproof coating pillar in which the fireproof coating is reduced compared to the fireproof coated pillar,
   Construction method of fireproof structure.
9. In a slab including a tensile force transmission member, a floor section partitioned into a polygonal shape having a plurality of corners in a plan view,
   A fireproof coated beam, which is provided with a fireproof coating and supports the periphery of the floor from below,
   A first refractory-covered column, which is provided with a refractory coating, supports the refractory-covered beam, and has a part of itself and the refractory-covered beam formed in an annular shape as a whole,
   An extension beam having a fireproof coating and coupled to a coupling corner that is at least one of the plurality of corners of the floor;
   A second refractory-coated column that is provided with a refractory coating and supports a portion of the extension beam that is different from the portion joined to the joining corner;
   Equipped with
   When the directions intersecting with each other in the plane of the floor are the first intersecting direction and the second intersecting direction, the tensile force transmitting member includes a tensile force between the ends of the floor in the first intersecting direction, And a method for constructing a refractory structure for constructing a refractory structure that transmits tensile forces between the ends of the floor portion in the second intersecting direction,
   The slab, a plurality of beams that support the slab from below, and a column-beam construction step that constructs a plurality of columns that support the plurality of beams,
   A fire-resistant coating beam is applied to the beam to form the fire-resistant coated beam, and a fire-resistant coating is applied to the column to form the first fire-resistant coated column, thereby surrounding the floor portion partitioned from the slab with the fire-resistant coated beam and A coating construction step in which the first refractory-coated pillar is supported from below by the part;
   A first supporting step in which the extension beam is coupled to the coupling corner, and a portion of the extension beam different from the portion coupled to the coupling corner is supported by the second refractory-coated column;
   A second supporting step in which the joint corner is not directly supported by a pillar, or is supported from below by a reduced fireproof coated pillar in which the fireproof coating is reduced compared to the first fireproof coated pillar,
   Construction method of fireproof structure.
10. In a slab including a tensile force transmission member, a floor section partitioned into a polygonal shape having a plurality of corners in a plan view,
    A fireproof coating is applied, and an annular fireproof beam that supports the periphery of the floor from below,
    An extension beam having a fireproof coating and coupled to a coupling corner that is at least one of the plurality of corners of the floor;
    A fireproof coated column, which is provided with a fireproof coating and supports a portion different from the portion connected to the connection corner of the extension beam,
    Equipped with
    When the directions intersecting with each other in the plane of the floor are the first intersecting direction and the second intersecting direction,
    The joint corner is not directly supported by a column, or is supported from below by a reduced fireproof coated column in which the fireproof coating is reduced more than the fireproof coated column,
    The tensile force transmitting member transmits a tensile force between the ends of the floor in the first intersecting direction and a tensile force between the ends of the floor in the second intersecting direction, respectively.
11. The refractory coating is reduced compared to the refractory coated beam, and the refractory coated beam is arranged in a region surrounded by the annular refractory coated beam, and an end portion is joined to the refractory coated beam to support the floor from below. The fire resistant structure according to claim 10, comprising a fire resistant coated beam.
12. The refractory structure according to claim 10 or 11, wherein the polygonal shape is a rectangular shape.
13. A maximum value of deflection of the floor portion during a desired heating time when heated according to a heating curve defined in ISO 834-11:2014 is less than a threshold value K defined by the equation (3). Item 13. The refractory structure according to any one of items 10 to 12.
    K=(L+1)/30 (3)
    Here, L is the length (m) of the first span along the plane of the floor, and l is the length (m of the second span along the plane of the floor and intersecting the first span. ).
14. The tensile force transmission member,
    A first reinforcing bar extending along the first intersecting direction and transmitting a tensile force between ends of the floor portion in the first intersecting direction;
    The fireproof structure according to any one of claims 10 to 13, further comprising a second reinforcing bar that extends along the second intersecting direction and that transmits a tensile force between ends of the floor portion in the second intersecting direction. object.
15. In a slab including a tensile force transmission member, a floor section partitioned into a polygonal shape having a plurality of corners in a plan view,
    A fireproof coated beam, which is provided with a fireproof coating and supports the periphery of the floor from below,
    A first refractory-covered column, which is provided with a refractory coating, supports the refractory-covered beam, and has a part of itself and the refractory-covered beam formed in an annular shape as a whole,
    An extension beam having a fireproof coating and coupled to a coupling corner that is at least one of the plurality of corners of the floor;
    A second refractory-coated column that is provided with a refractory coating and supports a portion of the extension beam that is different from the portion joined to the joining corner;
    Equipped with
    When the directions intersecting with each other in the plane of the floor are the first intersecting direction and the second intersecting direction,
    The joint corner is not directly supported by a column, or is supported from below by a reduced fireproof coated column in which the fireproof coating is reduced more than in the first fireproof coated column,
    The tensile force transmitting member transmits a tensile force between the ends of the floor in the first intersecting direction and a tensile force between the ends of the floor in the second intersecting direction, respectively.
16. A plurality of fireproof coated pillars, which are provided with a fireproof coating and are arranged side by side in a first intersecting direction along a horizontal plane, and are also arranged side by side at a first pitch in a second intersecting direction intersecting the first intersecting direction along a horizontal plane. When,
    A pair of first refractory-coated beams that are provided with a fire-resistant coating and that extend along the first intersecting direction and are spaced apart from each other in the second intersecting direction;
    A refractory coating is applied, extends along the second intersecting direction, is formed to have a length different from the first pitch, and both ends are directly bonded to the pair of first refractory-covered beams, and the plurality of A pair of second refractory-covered beams respectively joined to the refractory-covered columns of
    In a slab including a tensile force transmission member, a floor which is partitioned into a quadrangular shape having four corners in a plan view and whose periphery is supported from below by the pair of first fireproof coated beams and the pair of second fireproof coated beams Department,
    An extension beam having a fireproof coating and coupled to a coupling corner that is at least one of the four corners of the floor;
    Equipped with
    The joint corner is not directly supported by a column, or is supported from below by a reduced fireproof coated column in which the fireproof coating is reduced more than the fireproof coated column,
    The tensile force transmitting member transmits a tensile force between the end portions of the floor portion in the first intersecting direction and a tensile force between the end portions of the floor portion in the second intersecting direction, respectively.
    At least one of the plurality of refractory-covered columns is a refractory structure that supports a portion of the extension beam different from a portion coupled to the coupling corner.

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