Refractory sheathed beams

Abstract

To provide a fire resistively coated beam securing fire resistance efficiency, improved in load bearing performance, while rationalizing construction of fire resistive coating.SOLUTION: A fire resistively coated beam 100 comprises: a beam body 10 having an upper flange 11, a lower flange 12 and a web 13 connecting the upper flange 11 to the lower flange 12; an auxiliary material of the beam body 10 provided at the web 13; and fire resistive coating for coating the beam body 10 and the auxiliary material.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a fire-resistant coated beam. [Background technology]

[0002] In order to improve the fire resistance of steel beams used in structures such as buildings, fire-resistant coatings are sometimes applied. The following structure has been disclosed to make the installation of fire-resistant coatings easier and more efficient for workers. For example, Patent Document 1 describes inserting a bent steel plate into the bottom flange of an H-shaped steel beam to serve as a guide for determining the thickness of the fire-resistant covering material when it is applied.

[0003] Patent Document 2 discloses that by providing targets on the flanges and webs of an H-shaped steel beam that are the same height as the target thickness of the fire-resistant coating material, it is possible to easily apply the fire-resistant coating material to a specified thickness. Patent Document 3 describes a construction method in which a wrap-type fire-resistant coating material is attached to an H-shaped steel beam in an eight-shaped pattern, in which a block-shaped spacer made of an inorganic material is attached to the web to equalize the temperature difference between the upper and lower flanges, thereby lowering the temperature of the lower flange.

[0004] In Patent Document 4, angle bars are attached to the upper and lower flanges of an H-shaped steel beam, making it possible to easily install rock wool decorative panels. In Patent Document 5, vertical stiffeners and horizontal stiffeners are provided in the web near the end of the H-shaped steel beam to restrain local buckling of the web and ensure deformation capacity.

[0005] In Patent Document 6, horizontal stiffeners are provided in line symmetry with respect to the central axis of the cross section on the web near the end of the H-shaped steel beam, thereby suppressing local buckling and improving the cross-sectional performance. In Patent Document 7, a beam is configured with three flanges and two webs, and deformation such as buckling is prevented without providing a stiffening material such as a stiffener. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Utility Model Application Publication No. 59-152052 [Patent Document 2] Japanese Patent Application Publication No. 2020-125620 [Patent Document 3] Japanese Utility Model Application Publication No. 63-200011 [Patent Document 4] Japanese Patent Application Publication No. 63-210331 [Patent Document 5] Patent No. 6105878 [Patent Document 6] Patent No. 6375616 [Patent Document 7] Japanese Patent Application Publication No. 2018-31143 Summary of the Invention [Problem to be solved by the invention]

[0007] Steel beams used in structures require fire resistance. To meet this requirement, as mentioned above, a common method is to apply fire-resistant coating to columns and beams to reduce heat input in a fire and prevent collapse. However, there is a serious shortage of fire-resistant coating workers in Japan. This means that improving the technology to streamline the construction of fire-resistant coatings is an issue. On the other hand, sub-girders in structures do not require deformation performance. For this reason, there is a growing need to reduce the weight of the steel sections used in sub-girders by thinning their walls. However, thinning the walls of sub-girders raises concerns that their load-bearing capacity may decrease due to buckling. Furthermore, the reduced volume leads to a decrease in heat capacity. This raises concerns that the thickness of the fire-resistant coating may need to be increased. Thus, in the case of structural steel beams, in addition to improving load-bearing performance, the challenge is to reduce the amount of steel and covering material used. The inventors of the present application have attempted to solve these problems by using the inventions described in the above Patent Documents 1 to 7, but have been unable to solve the problems described below.

[0008] In Patent Document 1, the device for controlling the coating thickness does not bear stress and has no effect on improving the load-bearing performance of the beam. In Patent Document 2, the target does not bear stress, and there is no effect of improving the load-bearing performance of the beam. In Patent Document 3, the spacers do not bear stress and are not effective in improving the load-bearing capacity of the beam. Furthermore, it is difficult to apply fire-resistant coating to the H-section steel in a box-like manner, which is known as box-attaching. This makes it difficult to ensure a sufficient air gap, potentially resulting in inferior fire resistance compared to box-attaching.

[0009] In Patent Document 4, the angle irons do not bear stress and have no effect on improving the load-bearing capacity of the beam. Furthermore, the fire-resistant coating cannot be fastened at a height near the center between the upper and lower flanges of the web. Therefore, when the fire-resistant coating is exposed to heat from a fire, it may fall off due to its own weight as it deteriorates. In Patent Document 5, there is no effect on thickness management of fire-resistant coatings or construction assistance for vertical and horizontal stiffeners.

[0010] In Patent Document 6, the horizontal stiffener has no effect on controlling the thickness of the fire-resistant coating or assisting in construction. In Patent Document 7, the flange provided in the center of the cross section in the height direction has no effect on controlling the thickness of the fire-resistant coating or assisting in construction.

[0011] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a fire-resistant coated beam that improves load-bearing performance and ensures fire resistance while streamlining the installation of fire-resistant coatings. [Means for solving the problem]

[0012] In order to solve the above problems, the present invention proposes the following means. The fire-resistant coated beam of the present invention comprises a beam body having an upper flange, a lower flange, and a web connecting the upper flange and the lower flange, a reinforcing material for the beam body provided on the web, and a fire-resistant coating that covers the beam body and the reinforcing material.

[0013] According to this invention, a beam is provided with a beam body, a reinforcing member attached to the web of the beam body, and a fire-resistant coating that covers the beam body and the reinforcing member. By arranging the reinforcing member on the web, it is possible to improve the buckling strength while avoiding an increase in the thickness of the web. This allows the load-bearing capacity to be improved while minimizing the increase in the weight of the beam body. Furthermore, by covering the beam body and the auxiliary members with fire-resistant coating, the auxiliary members act as a thermal bridge, preventing heat transfer to the webs. This prevents a decrease in the fire resistance of the beam body. This results in a fire-resistant coated beam that improves load-bearing capacity and ensures fire resistance.

[0014] Furthermore, the reinforcing members do not have to be provided at the longitudinal ends of the beam body.

[0015] When attaching a fire-resistant covered beam to a structure such as a girder, the beam is primarily joined by fastening members at both longitudinal ends. In contrast, no reinforcing members are provided at the longitudinal ends of the beam body. This allows the sections without reinforcing members to have the same cross-section as a regular steel beam, consisting only of a flange and web, in the longitudinal direction of the fire-resistant covered beam. This facilitates the calculation of the moment of inertia and section modulus used in strength design, facilitating design considerations.

[0016] The fire-resistant coating may be a sprayed material.

[0017] According to this invention, the fire-resistant coating is a spray-applied material. This allows the installer to apply the fire-resistant coating by spraying the auxiliary material onto the beams after they have been joined to the structure, using it as a guide for the coating thickness, without having to make any prior preparations to match the dimensions of the construction site. This makes the installer's work easier.

[0018] Furthermore, the portion of the fire-resistant coating that covers one of the upper flange and the lower flange may be stacked in the vertical direction relative to the surface of the one flange facing the other flange, the auxiliary material may be positioned closer to the one flange than the other flange and may be a plate-shaped member parallel to the one flange, and the first side surface of the auxiliary material that faces the other flange may be positioned in a position that is aligned with the surface of the fire-resistant coating stacked on the one flange, or closer to the one flange than the position that is aligned with the surface of the fire-resistant coating.

[0019] According to this invention, the first surface of the auxiliary material facing the other flange is positioned so that it is flush with the surface of the fire-resistant coating stacked on one flange, or is positioned closer to the one flange than the surface of the fire-resistant coating. This allows the thickness of the fire-resistant coating to be determined by spraying the fire-resistant coating onto the upper or lower flange until the auxiliary material is no longer visible. Then, by applying the fire-resistant coating to the web to an appropriate thickness, the tip of the auxiliary material will not be exposed from the surface of the fire-resistant coating, and the auxiliary material will not form a thermal bridge. This improves the efficiency of the fire-resistant coating application process.

[0020] In addition, in the width direction of the beam body, the dimension of the auxiliary material is more than 1 / 3 and less than 2 / 3 of the covering thickness of the fire-resistant coating, and a pin is arranged at the end of the auxiliary material, which is one of the two ends of the auxiliary material in the width direction of the beam body, and the height of the pin combined with the dimension of the auxiliary material in the width direction of the beam body is equal to the covering thickness of the fire-resistant coating on the auxiliary material, and the pins may be arranged in the width direction of the beam body at a pitch of 500 mm or less along the longitudinal direction of the beam body.

[0021] According to this invention, the dimensions of the reinforcing material are between 1 / 3 and 2 / 3 of the thickness of the fire-resistant coating. This prevents the tip of the reinforcing material from being located close to the surface of the fire-resistant coating, and allows the reinforcing material itself to have a buckling stiffening effect. As a result, the reinforcing material does not become a thermal bridge in the event of a fire, preventing a decrease in fire resistance, and also improves the buckling strength of the beam body.

[0022] Furthermore, the height of the pins combined with the dimensions of the auxiliary material in the width direction of the beam body equals the thickness of the fire-resistant coating covering the auxiliary material. This allows the pins to be used as markers when installing the fire-resistant coating, as they are no longer visible from the outside. Furthermore, by keeping the spacing between pins at 500 mm or less, workers can visually check multiple pins at the same time. This prevents areas where the fire-resistant coating is not installed to a sufficient height between pins. This prevents the auxiliary material from becoming a thermal bridge and makes the installation of the fire-resistant coating more efficient.

[0023] The fire-resistant coating may be a wrapping material.

[0024] According to this invention, the fire-resistant covering is a wrapping material, which makes it possible to minimize the number of workers required for construction and to maintain a good environment at the construction site.

[0025] In addition, in the width direction of the beam body, the dimension of the auxiliary material may be equal to the distance from the surface of the web to the end of the upper flange or the distance from the surface of the web to the end of the lower flange.

[0026] According to this invention, the dimension of the auxiliary member in the width direction of the beam body is equal to the distance from the surface of the web to the end of the upper flange or the distance from the surface of the web to the end of the lower flange. This allows the auxiliary member to function as a spacer. Specifically, when applying the fire-resistant coating, which is a wrapping material, the fire-resistant coating is arranged so that it contacts at least one of the ends of the upper flange or the lower flange and the end of the auxiliary member, respectively, so that the application can be performed without creating any steps on the surface of the fire-resistant coating. This improves the appearance of the surface of the fire-resistant coating and improves application workability. Furthermore, the auxiliary member functions as a spacer, ensuring an air layer between the web and the fire-resistant coating.

[0027] In addition, the fastening material for the fire-resistant coating may be arranged at the end of the auxiliary material, which is the end opposite to the side facing the web, of the two ends of the auxiliary material in the width direction of the beam body.

[0028] According to this invention, a fastening material for the fire-resistant coating is disposed on the end of the auxiliary material opposite to the end that contacts the web. This allows the fire-resistant coating to be fixed to the auxiliary material. This prevents the fire-resistant coating from falling off under its own weight as it deteriorates due to heat from a fire.

[0029] The auxiliary material may also include at least one of a horizontal auxiliary material arranged on the web so that its plate-shaped plane is parallel to the upper flange or the lower flange, and a vertical auxiliary material arranged on the web so that its plate-shaped plane is perpendicular to the upper flange or the lower flange.

[0030] According to the present invention, at least one of horizontal reinforcing members and vertical reinforcing members is provided, which can further improve the buckling strength of the fire-resistant covered beam.

[0031] The auxiliary member may be a plate-shaped member, and the thickness of the auxiliary member may be 6 mm or more.

[0032] According to this invention, the thickness of the auxiliary material is 6 mm or more. This ensures that an area for placing pins or fastening materials can be secured on the side surface of the auxiliary material in the thickness direction that faces the fire-resistant coating. Furthermore, the auxiliary material can provide sufficient strength to the fire-resistant coated beam.

[0033] The reinforcing members may be arranged continuously or intermittently in the longitudinal direction of the beam body.

[0034] According to this invention, the reinforcing members are arranged continuously or intermittently in the longitudinal direction of the beam body. Therefore, the form of the reinforcing members can be appropriately selected according to the requirements of the structure to which the fire-resistant coated beam is to be installed. When the reinforcing members are arranged continuously, the number of steel plates used can be minimized. When the reinforcing members are arranged intermittently, the increase in weight of the fire-resistant coated beam due to the reinforcing members can be minimized. [Effects of the Invention]

[0035] According to the present invention, it is possible to provide a fire-resistant coated beam that improves load-bearing performance and ensures fire resistance while streamlining the application of fire-resistant coating. [Brief explanation of the drawings]

[0036] [Figure 1] This is the first example of a fire-resistant coated beam in which sprayed material is used as fire-resistant coating. [Figure 2] This is the second example of a fire-resistant coated beam in which wrapping material is placed as fire-resistant coating. [Figure 3] This is an example of a fire-resistant coated beam with auxiliary materials placed on it, as shown in Figure 1. [Figure 4] This is an example of a fire-resistant coated beam with auxiliary materials placed on it, as shown in Figure 2. [Figure 5] 4 is a first example of a side view of the beam body of the fire-resistant coated beam shown in FIG. 3. [Figure 6] 4 is a second example of a side view of the beam body of the fire-resistant coated beam shown in FIG. 3. [Figure 7] FIG. 5 is a first example of a side view of the beam body of the fire-resistant coated beam shown in FIG. 4. [Figure 8] 5 is a second example of a side view of the beam body of the fire-resistant coated beam shown in FIG. 4. [Figure 9] FIG. 4 is an enlarged view of part IX shown in FIG. [Figure 10] FIG. 6 is an enlarged view of the X portion shown in FIG. 5. [Figure 11] FIG. 2 is a perspective view of a beam body of a fire-resistant coated beam according to the first example. [Figure 12] FIG. 10 is a perspective view of the beam body of a fire-resistant coated beam according to a second example. [Figure 13] 1 is a standard heating curve according to the analysis of this embodiment. [Figure 14] 10 shows boundary conditions for the heat conduction analysis according to the present embodiment. [Figure 15] 10 shows external force conditions for thermoelectric analysis according to this embodiment. [Figure 16] 1 is a first temperature sampling point for the analysis of the fire-resistant coated beam of the first example. [Figure 17] This is the result of the heat conduction analysis at the first temperature sampling point. [Figure 18] 10 is a second temperature sampling point for the analysis of the fire-resistant coated beam of the first example. [Figure 19] This is the result of the heat conduction analysis at the second temperature sampling point. [Figure 20] 10 shows temperature sampling points for the analysis of the fire-resistant coated beam in the second example. [Figure 21] This is the result of a heat conduction analysis at the temperature sampling points shown in FIG. [Figure 22] 10 is an analysis result showing the correlation between heating time and maximum deflection of the fire-resistant coated beam according to the first example. [Figure 23] 10 is an analysis result showing the correlation between heating time and maximum deflection of the fire-resistant coated beam according to the second example. [Figure 24] This is the collapse type of the fire-resistant coated beam in Example 1 when no auxiliary material is provided. [Figure 25] This is the collapse type of the fire-resistant coated beam in Example 1 when a 15mm wide auxiliary material is installed. [Figure 26] This is the collapse type of the fire-resistant coated beam in Example 1 when a 30mm wide auxiliary material is installed. [Figure 27] This is the collapse type of the fire-resistant coated beam in the second example when no auxiliary material is provided. [Figure 28] This is the collapse type of the fire-resistant coated beam in the second example when auxiliary materials are provided. DETAILED DESCRIPTION OF THE INVENTION

[0037] Hereinafter, a fire-resistant coated beam according to one embodiment of the present invention will be described with reference to the drawings. 1 and 2 show a conventional H-shaped steel beam (beam body 10) to which a fire-resistant coating 30 is applied. In the example shown in FIG. 1, the fire-resistant coating 30 is applied along the surface of the H-shaped steel beam, and a so-called sprayed material 31 is used. In the example shown in FIG. 2, a sheet-like fire-resistant coating 30 is applied to cover the periphery of the H-shaped steel beam, and a so-called wrapping material 32 is used. The present invention improves buckling strength while suppressing an increase in weight by adding the following configuration to the fire-resistant coated beam 100 having the above configuration.

[0038] 3 and 4, the fire-resistant coated beam 100 includes a beam body 10, a reinforcing member 20, and a fire-resistant coating 30. The fire-resistant coated beam 100 is used as a column or beam in a structure such as a building. The beam body 10 includes an upper flange 11, a lower flange 12, and a web 13. In this embodiment, the beam body 10 is a so-called H-shaped steel.

[0039] The upper flange 11 is a flange located on the upper side of the beam body 10, which is an H-shaped steel. The upper flange 11 is a plate-shaped member, and is disposed facing the slab S in the structure as shown in Figs. 3 and 4. The lower flange 12 is a flange located on the lower side of the beam body 10, which is an H-shaped steel. The lower flange 12 is a plate-shaped member similar to the upper flange 11, and is provided parallel to the upper flange 11. The web 13 connects the upper flange 11 and the lower flange 12. The web 13 is a plate-shaped member and is disposed perpendicular to the upper flange 11 and the lower flange 12.

[0040] The beam body 10 is formed of a steel material. The yield strength of the steel material used for the beam body 10 is defined as follows. Yield strength σ y is, for example, the yield point or yield strength specified in JIS G 3101:2015. Yield strength σ y is the yield strength of the steel material at room temperature. Room temperature is, for example, the room temperature specified in JIS Z 2241:2011. Room temperature is, for example, 20°C±15°C (5°C to 35°C). For example, the yield strength of steel at room temperature is σ y、RT When this is the case, the steel material used for the beam body 10 is σ y、RT ≧235N / mm 2 Steel, σ y、RT ≧295N / mm 2 Steel, σ y、RT ≧325N / mm 2 Steel, σ y、RT ≧385N / mm 2 The above steel materials are preferably used. The steel material used for the beam body 10 is not limited to the above-mentioned steel material, and may be appropriately determined based on conditions such as strength required for the structure in which the fire-resistant coated beam 100 is used.

[0041] The reinforcing members 20 are attached to the web 13 to increase the buckling strength of the beam body 10. The reinforcing members 20 are attached to the web 13 by single-sided or double-sided fillet welding. The reinforcing members 20 include horizontal reinforcing members 21 and vertical reinforcing members 22. In the fire-resistant coated beam 100, both the horizontal reinforcing members 21 and the vertical reinforcing members 22 may be provided, or only one of them may be provided. Hereinafter, when there is no need to distinguish between the horizontal reinforcing members 21 and the vertical reinforcing members 22, they will be referred to as reinforcing members 20.

[0042] The horizontal reinforcement members 21 are plate-shaped members arranged on the web 13 so as to be parallel to the upper flange 11 or the lower flange 12. The longitudinal direction of the horizontal reinforcement members 21 is along the longitudinal direction X of the beam body 10. The horizontal reinforcement members 21 are provided continuously in the longitudinal direction X of the beam body 10 as shown in Figures 5 and 7, or multiple horizontal reinforcement members 21 are provided discontinuously at intervals as shown in Figures 6 and 8.

[0043] 1 etc., the longitudinal direction X of the beam body 10 will be simply referred to as the longitudinal direction X, and the direction perpendicular to the vertical direction Z and the longitudinal direction X will be referred to as the width direction Y (width direction Y of the beam body 10). In other words, the thickness direction of the plate-like shape of the upper flange 11 and the lower flange 12 will be referred to as the vertical direction Z, one of the directions perpendicular to the vertical direction Z will be referred to as the width direction Y, and the direction perpendicular to both the vertical direction Z and the width direction Y will be referred to as the longitudinal direction X. The horizontal reinforcement member 21 has a number of mounting configurations. For example, as shown in Figures 3, 5, and 6, the horizontal reinforcement member 21 may be disposed near the upper flange 11 or the lower flange 12, or as shown in Figures 4, 7, and 8, the horizontal reinforcement member 21 may be disposed at the center of the web 13 in the vertical direction Z. These mounting configurations correspond to the configurations of the fire-resistant coating 30 described below.

[0044] The vertical reinforcement member 22 is arranged on the web 13 so that the plate-shaped plane is perpendicular to the upper flange 11 or the lower flange 12. The vertical reinforcement member 22 may be attached only to the web 13, or may be attached together with the upper flange 11 or the lower flange 12. A plurality of vertical reinforcement members 22 may be provided in the longitudinal direction X of the beam body 10, or may be provided in only one location. The auxiliary material 20 may have, for example, σ y、RT ≧235N / mm 2 The steel material used for the auxiliary member 20 is not limited to this, and may be appropriately determined based on the conditions such as the strength required for the structure in which the fire-resistant coated beam 100 is used.

[0045] As shown in Figures 5 to 8, the reinforcing members 20 are not provided at the ends of the beam body 10 in the longitudinal direction X. In this embodiment, the "ends" refer to the beam depth from the ends toward the center of the beam body 10 in the longitudinal direction X, i.e., the region having the same length as the overall length in the vertical direction Z, preferably 50% of the beam depth. This prevents the reinforcing members 20 from interfering with bolted joints in the web 13. When examining the strength of the fire-resistant coated beam 100, the second moment of area and the section modulus are calculated based on the shape of the end where the reinforcing members 20 are not provided. The strength of the portion where the reinforcing members 20 are not provided is lower than that of the portion where the reinforcing members 20 are provided. Therefore, examining the strength based on the portion where the reinforcing members 20 are not provided allows for a generous design margin, and calculating the second moment of area and the section modulus without taking the reinforcing members 20 into account avoids complication of the strength examination.

[0046] The fire-resistant coating 30 covers the beam body 10 and the auxiliary material 20, thereby preventing heat from propagating to the beam body 10 and the auxiliary material 20 and reducing their strength. There are two types of fire-resistant coating: one that is sprayed onto the beam body 10 so that it is positioned along the surface of the beam body 10 as shown in FIG. 3, and one that is wrapped around the beam body 10 so that it has an air layer A with respect to the web 13 of the beam body 10 as shown in FIG. 4. Hereinafter, the fire-resistant coating 30 that is sprayed onto the beam body 10 will be referred to as a sprayed material 31. The fire-resistant coating 30 that is wrapped around the beam body 10 will be referred to as a wrapped material 32. When there is no need to distinguish between the sprayed material 31 and the wrapped material 32, they will be referred to as the fire-resistant coating 30.

[0047] Rock wool, for example, is preferably used as the spraying material 31. The spraying material 31 is sprayed after the beam body 10 is installed on the structure at the construction site. In order to ensure that the spraying material 31 provides sufficient performance required of the fire-resistant coating 30, it is necessary that the spraying material 31 be sprayed to a sufficient thickness on the surface of the beam body 10. Hereinafter, the thickness of the spraying material 31 on the surface of the beam body 10 is referred to as the covering thickness.

[0048] The portion of the spray material 31 that covers one of the upper flange 11 and the lower flange 12 is piled up in the vertical direction Z with respect to the surface of one flange facing the other flange. In addition, the portion of the spray material 31 that covers the web 13 is piled up in the width direction Y. When the sprayed material 31 is used for the fire-resistant covering 30, the horizontal reinforcement members 21 are attached to the web 13 as follows. That is, as shown in Figures 3, 5, and 6, the horizontal reinforcement members 21 are positioned closer to one flange than to the other flange. More specifically, as shown in Figure 9, the first surface of the horizontal reinforcement member 21 facing the other flange is positioned so that it is flush with the surface of the fire-resistant covering 30 stacked on one flange, or is positioned closer to one flange than the surface of the fire-resistant covering 30.

[0049] By using this type of installation method, the first side surface of the horizontal support member 21 is positioned within the covering thickness of the sprayed material 31 placed on the upper flange 11 or lower flange 12, or is at least aligned with the surface of the fire-resistant coating. When the spray material 31 is sprayed onto the web 13, a layer of fire-resistant coating 30 is formed on the surface of the web 13. If the first side surface of the horizontal reinforcing member 21 is positioned outside the surface of the spray material 31 arranged on the upper flange 11 or the lower flange 12 in the vertical direction Z of the web 13, the thickness of the fire-resistant coating 30 covering the reinforcing member 20 attached to the surface of the web 13 may not be ensured. Alternatively, the tip of the reinforcing member 20 may be exposed from the surface of the fire-resistant coating sprayed onto the web 13. This exposed portion may act as a thermal bridge and transfer heat to the web 13. To avoid this, when using the spray material 31 for the fire-resistant coating 30, the horizontal reinforcing member 21 is attached to the web 13 in the manner described above.

[0050] In the width direction Y of the beam body 10, the dimension of the auxiliary material 20 is set to be 1 / 3 or more and 2 / 3 or less of the covering thickness of the sprayed material 31. By setting such dimensions, the improvement of load-bearing performance by providing the auxiliary material 20 is ensured, and heat propagation to the beam body 10 through the auxiliary material 20 is prevented. As shown in FIG. 10 , a pin P is arranged at the end of the auxiliary material 20, which is one of two ends of the auxiliary material 20 in the width direction Y of the beam body 10, on the end opposite the side facing the web 13. The pin P protrudes from the auxiliary material 20 in the width direction Y. The pin P is attached to the auxiliary material 20 by resistance welding, in which electricity is passed between the auxiliary material 20 and the casting tool. In order to enable the pin P to be attached to the auxiliary material 20, the plate-like thickness of the auxiliary material 20 is set to 6 mm or more.

[0051] The height of the pins P combined with the dimensions of the auxiliary material 20 in the width direction Y of the beam body 10 is equal to the covering thickness of the fire-resistant coating 30 on the auxiliary material 20. The pins P are arranged along the width direction Y of the beam body 10 at a pitch of 500 mm or less in the longitudinal direction X of the beam body 10. When applying the spray material 31 at the construction site, the spray material 31 is sprayed until the auxiliary material 20 and the pins P are no longer visible from the outside. This allows the auxiliary material 20 to serve as a guide for the covering thickness of the spray material 31 in addition to its role as stiffening.

[0052] Table 1 shows the relationship between the dimensions of the auxiliary material 20 and pin P relative to the covering thickness of the sprayed material 31 and the certified fire resistance time for the fire-resistant coated beam 100 to which the sprayed material 31 having the above-mentioned configuration has been applied (spraying method). The certified fire resistance time refers to the time at which fire resistance performance is certified to be guaranteed in the standard heating curve according to ISO-834, which will be described later. As shown in Table 1, the certified fire resistance time is proportional to the covering thickness (coating thickness) of the sprayed material 31. The dimensions of the auxiliary material 20 are each 66% (2 / 3) of the covering thickness.

[0053] [Table 1]

[0054] The wrapping material 32 is a sheet-like member made of, for example, nonwoven fabric and rock wool. As shown in Figure 4, the wrapping material 32 is arranged so as to cover the periphery of the beam body 10 installed in the structure. The wrapping material 32 arranged in this manner is fixed by fastening material F. When the wrapping material 32 is used for the fire-resistant covering 30, the horizontal reinforcement member 21 is attached to the web 13 in the following manner: That is, as shown in Figures 4, 7 and 8, the horizontal reinforcement member 21 is disposed at the center of the web 13 in the vertical direction Z.

[0055] In the width direction Y of the beam body 10, the dimension of the horizontal reinforcement member 21 is equal to the distance from the surface of the web 13 to the end of the upper flange 11 or the distance from the surface of the web 13 to the end of the lower flange 12. In other words, the end of the horizontal reinforcement member 21 and at least one of the end of the upper flange 11 or the end of the lower flange 12 are aligned in the width direction Y.

[0056] By adopting such an attachment mode, the horizontal support member 21 functions as a spacer, and it is ensured that an air layer A is provided between the web 13 and the wrapping material 32 . Furthermore, the fastening material F is disposed at the end of the auxiliary material 20, that is, at one of the two ends of the auxiliary material 20 in the width direction Y of the beam body 10, the end opposite the side facing the web 13. The fastening material F is attached to the auxiliary material 20 by welding. This prevents the fire-resistant coating from falling off as it deteriorates due to heat from a fire.

[0057] Table 2 shows the weight comparison results for the fire-resistant coated beam 100 with the above-described configuration, with and without the auxiliary member 20 (H-shaped steel). According to this table, when the dimensions of each part of the cross section of the H-shaped steel are shown in the order of "beam depth x beam width x web thickness x flange thickness," the steel weight of an H-shaped steel with a cross section of 700 x 175 x 4.5 x 9 is 48.8 kg / m. The steel weight of an H-shaped steel with a cross section of 700 x 175 x 6 x 9 is 56.8 kg / m. In contrast, when the auxiliary member 20 is attached to an H-shaped steel (beam body 10) with a cross section of 700 x 175 x 4.5 x 9, the steel weight does not exceed the steel weight of an H-shaped steel with a cross section of 700 x 175 x 6 x 9 in any example. In other words, it can be confirmed that the installation of the auxiliary member 20 does not result in a significant increase in steel weight.

[0058] [Table 2]

[0059] (Thermal analysis of fireproof coated beam 100) Next, the results of a thermal analysis of the fire-resistant coated beam 100 having the above-described configuration will be described. The beam body 10 shown in Figure 11 is an example where the fire-resistant coating 30 is a sprayed material 31. In other words, this is a case where horizontal reinforcement members 21 are attached near the upper flange 11 and the lower flange 12. Hereinafter, this example will be referred to as Example 1. The beam body 10 shown in Figure 12 is an example where the fire-resistant coating 30 is a wound material 32. In other words, this is a case where the horizontal reinforcement member 21 is placed at the center of the web 13 in the vertical direction Z. Hereinafter, this example will be referred to as Example 2. In this analysis, in both Examples 1 and 2, vertical reinforcement members 22 are provided at positions 1,400 mm from both ends of the beam body 10 in the longitudinal direction X.

[0060] An analysis was performed on the fire-resistant coated beams 100 according to the above-mentioned two examples, in the case where they were heated along the heating curve shown in Fig. 13. Fig. 13 is a standard heating curve according to ISO-834. The boundary conditions for the fire-resistant coated beam 100 are as shown in FIG. 14. Specifically, the total length of the fire-resistant coated beam 100 in the longitudinal direction X is 7600 mm, and the total length in the vertical direction Z is 700 mm. In this analysis, as shown in FIG. 14, stiffeners St, which are separate members from the vertical reinforcing members 22, are arranged in the longitudinal direction X of the fire-resistant coated beam 100 as follows: That is, they are arranged in four locations: one at a position 200 mm from each end in the longitudinal direction X, and one at a position 2600 mm from each end. The stiffeners St are stiffening materials provided on the fire-resistant coated beam 100 in the analysis to prevent it from failing in a way that differs from the actual situation at concentrated load points (loading points and support points) in the analysis. Moreover, the fixed and free conditions for displacement and rotation at the three points α, β, and γ in FIG. 14 are set as shown in the table in FIG. The external force conditions for the fire-resistant coated beam 100 are as shown in Figure 15. Specifically, in the longitudinal direction X of the fire-resistant coated beam 100, positions 200 mm from both ends in the longitudinal direction X are fixed from below. In other words, for the calculation of bending moment, the total length of the fire-resistant coated beam 100 is 7200 mm, which is the above-mentioned 7600 mm minus 400 mm from both ends. In addition, an external force of 116 kN is applied from above to below at points 2600 mm from both ends. Under each of the above conditions, the following analysis was performed using the fire-resistant coated beam 100 according to the first and second examples.

[0061] As shown in Fig. 16, a heat conduction analysis was performed on the fire-resistant coated beam 100 according to the first example, with the base of the horizontal reinforcing member 21 located near the upper flange 11 set as the first temperature sampling point M1, and the results shown in Fig. 17 were obtained. Fig. 17 is a graph in which the horizontal axis represents the ratio bs / tp (ratio of the reinforcing member width to the coating thickness) and the vertical axis represents the temperature at the first temperature sampling point M1, where bs represents the dimension of the horizontal reinforcing member 21 shown in Fig. 16 and tp represents the covering thickness of the sprayed material 31.

[0062] The plots in Figure 17 are based on the following conditions: RW60_3h is the temperature after 180 minutes of heating when the covering thickness of the spraying material 31 is 60 mm; RW45_2h is the temperature after 120 minutes of heating when the covering thickness is 45 mm; and RW25_1h is the temperature after 60 minutes of heating when the covering thickness is 25 mm.

[0063] 17, in any of the above cases, when the ratio of the auxiliary material width to the covering thickness is 0.66 or less, that is, when the dimension of the auxiliary material 20 is 2 / 3 or less of the covering thickness, there is no significant difference in the temperature at the first temperature sampling point M1, but when it exceeds 2 / 3, the temperature tends to rise. In other words, it can be seen that when the dimension of the auxiliary material 20 is 2 / 3 or less of the covering thickness, heat transmission from the auxiliary material 20 to the beam body 10 is suppressed.

[0064] The above results are also seen to be the same at the second temperature sampling point M2 shown in Figure 18. The second temperature sampling point M2 is the base of the horizontal reinforcing member 21 located near the bottom flange 12 of the fire-resistant coated beam 100 according to the first example. Figure 19 shows plots at the second temperature sampling point M2 under the same conditions as the graph shown in Figure 17.

[0065] For the fire-resistant coated beam 100 of the second example, the root of the horizontal reinforcing member 21, which is positioned at the center of the web 13 in the vertical direction Z as shown in FIG. 20, was set as the third temperature sampling point M3, and the results shown in FIG. 21 were obtained. FIG. 21 is a graph with the heating time of the fire-resistant coated beam 100 on the horizontal axis and the temperature on the vertical axis. FIG. 21 shows the results when the thickness of the wrapping material 32 was 40 mm and the dimension of the reinforcing member 20 was 85.25 mm. As shown in FIG. 21, it can be seen that the temperature rise was more suppressed when the reinforcing member 20 was provided than when the reinforcing member 20 was not provided. It can be seen that the above results were obtained because the provision of the reinforcing member 20 increased the volume of the central portion of the web 13, thereby increasing its heat capacity.

[0066] 22 and 23 are graphs in which the horizontal axis represents the heating time of the fire-resistant coated beam 100 and the vertical axis represents the maximum deflection of the fire-resistant coated beam 100. Fig. 22 shows the results for the fire-resistant coated beam 100 according to the first example. For the results shown in Fig. 22, the covering thickness tp of the sprayed material 31 is 45 mm. Fig. 23 shows the results for the fire-resistant coated beam 100 according to the second example.

[0067] As shown in Fig. 22, in the first example, when the reinforcing material 20 is not provided, the amount of deflection cannot be measured at the time point of 107 minutes, which indicates that the deflection has reached its limit. In contrast, when the dimensions of the auxiliary material 20 were set to bs = 15 mm (i.e., bs / tp = 1 / 3) and bs = 30 mm (i.e., bs / tp = 2 / 3), the following results were obtained. When bs / tp = 1 / 3, it becomes impossible to measure the amount of deflection after about 112 minutes, and the deflection reaches its limit. Therefore, it can be seen that if the dimensions of the auxiliary material 20 are at least 1 / 3 of the covering thickness of the sprayed material 31, the load-bearing capacity is improved compared to when the auxiliary material 20 is not provided. When bs / tp=2 / 3, the deflection reaches its limit value at 119 minutes. Furthermore, the increase in deflection until it reaches the deflection limit value is slower than when the auxiliary material 20 is not provided or when bs / tp=1 / 3. This shows that the buckling strength is increased by providing the auxiliary material 20.

[0068] As shown in Figure 23, when the auxiliary material 20 is not provided in the second example, the deflection reaches its limit at 107 minutes, as in the first example. In contrast, when the auxiliary material 20 is provided in the second example, the deflection reaches its limit at 130 minutes. As such, in both the first and second examples, it can be seen that when the auxiliary material 20 is provided, the rate of increase in the amount of deflection is slower and it takes longer to reach the deflection limit.

[0069] 24 to 28 visualize the collapse patterns of the fire-resistant coated beam 100 based on the results shown in FIGS. 22 and 23. Specifically, they are as follows. FIG. 24 shows the collapse pattern of the fire-resistant coated beam 100 according to the first example when no auxiliary material 20 is provided. FIG. 25 shows the collapse pattern of the fire-resistant coated beam 100 according to the first example when an auxiliary material 20 with bs = 15 mm is provided. FIG. 26 shows the collapse pattern of the fire-resistant coated beam 100 according to the first example when an auxiliary material 20 with bs = 30 mm is provided. FIG. 27 shows the collapse pattern of the fire-resistant coated beam 100 according to the second example when no auxiliary material 20 is provided. FIG. 28 shows the collapse pattern of the fire-resistant coated beam 100 according to the second example when an auxiliary material 20 is provided.

[0070] As shown in Figures 24 and 27, it can be seen that the fire-resistant coated beam 100 is significantly deformed when no auxiliary material 20 is provided. In contrast, as shown in Figures 25, 26, and 28, it can be seen that when the auxiliary material 20 is provided, deformation is suppressed more than when no auxiliary material 20 is provided. As described above, it was confirmed by analysis that the function of the fire-resistant coated beam 100 is improved by providing the auxiliary material 20 to the beam body 10.

[0071] As described above, the fire-resistant coated beam 100 according to this embodiment includes the beam body 10, the auxiliary members 20 provided on the webs 13 of the beam body 10, and the fire-resistant coating 30 that covers the beam body 10 and the auxiliary members 20. By disposing the auxiliary members 20 on the webs 13, it is possible to improve the buckling strength while avoiding an increase in the thickness of the webs 13. This makes it possible to improve the load-bearing capacity while minimizing an increase in the weight of the beam body 10. Furthermore, by covering the beam body 10 and the auxiliary material 20 with the fire-resistant coating 30, the auxiliary material 20 acts as a thermal bridge, preventing heat from being transmitted to the web 13 by the auxiliary material 20. This prevents a decrease in the fire resistance of the beam body 10. This allows for a fire-resistant coated beam 100 that improves load-bearing performance and ensures fire resistance.

[0072] Here, when the fire-resistant coated beam 100 is attached to a structure such as a girder, it is joined mainly by attaching fastening members to both ends in the longitudinal direction X. In contrast, the reinforcing members 20 are not provided at the ends of the beam body 10 in the longitudinal direction X. As a result, the section where the reinforcing members 20 are not provided has the same cross section as a general structural steel beam in the longitudinal direction X, consisting only of a flange and a web 13. This makes it easy to calculate the moment of inertia and section modulus used in strength design, facilitating design considerations.

[0073] Furthermore, the fire-resistant coating 30 is a sprayed material 31. This allows the builder to apply the fire-resistant coating 30 by spraying the auxiliary material 20 onto the beams after they have been joined to the structure, using it as a guide for the coating thickness, without having to make any prior preparations to match the dimensions of the construction site, etc. This makes the work easier for the builder.

[0074] Furthermore, the first surface of the auxiliary material 20, which faces the other flange, is positioned so that it is flush with the surface of the fire-resistant coating 30 stacked on one flange, or is positioned closer to the other flange than the surface of the fire-resistant coating 30. This allows the fire-resistant coating 30 to be sprayed onto the upper flange 11 or the lower flange 12 until the auxiliary material 20 is no longer visible, which serves as a guide for the thickness of the fire-resistant coating 30. Then, by applying the fire-resistant coating to the web to an appropriate thickness, the tip of the auxiliary material will not be exposed from the surface of the fire-resistant coating, and the auxiliary material will not form a thermal bridge. This improves the efficiency of the application of the fire-resistant coating 30.

[0075] Furthermore, the dimensions of the reinforcing material 20 are between 1 / 3 and 2 / 3 of the covering thickness of the fire-resistant coating 30. This prevents the tip of the reinforcing material 20 from being located close to the surface of the fire-resistant coating 30, and allows the reinforcing material 20 itself to have a buckling stiffening effect. Therefore, the reinforcing material 20 does not become a thermal bridge in the event of a fire, preventing a decrease in fire resistance, and the reinforcing material 20 can improve the buckling strength of the beam body 10.

[0076] Furthermore, the height of the pins P combined with the dimensions of the auxiliary members 20 in the width direction Y of the beam body 10 equals the thickness of the fire-resistant coating 30 covering the auxiliary members 20. As a result, when the fire-resistant coating 30 is applied, the pins P can be used as markers to indicate that they are not visible from the outside. Furthermore, since the spacing between the pins is 500 mm or less, workers can visually check multiple pins P simultaneously. This prevents the occurrence of areas where the fire-resistant coating 30 is not applied to a sufficient height between the pins. This prevents the auxiliary members 20 from becoming thermal bridges and makes the application of the fire-resistant coating 30 more efficient.

[0077] In addition, the fire-resistant coating 30 is the wrapping material 32. This makes it possible to minimize the number of workers required for construction. Furthermore, it is possible to maintain a good environment at the construction site.

[0078] Furthermore, in the width direction Y of the beam body 10, the dimension of the auxiliary member 20 is equal to the distance from the surface of the web 13 to the end of the upper flange 11 or the distance from the surface of the web 13 to the end of the lower flange 12. This allows the auxiliary member 20 to function as a spacer. Specifically, when the fire-resistant coating 30 (wrapping material 32) is applied, the fire-resistant coating 30 is positioned so that it contacts at least one of the ends of the upper flange 11 and the lower flange 12 and the end of the auxiliary member 20, respectively. This allows the fire-resistant coating 30 to be applied without creating any steps on its surface. This improves the appearance of the surface of the fire-resistant coating 30 and enhances the ease of application. Furthermore, the auxiliary member 20 functions as a spacer, ensuring an air layer A between the web 13 and the fire-resistant coating 30.

[0079] Additionally, fastening material F for the fire-resistant coating 30 is disposed at the end of the auxiliary material 20 opposite to the side that contacts the web 13. This allows the fire-resistant coating 30 to be fixed to the auxiliary material 20. This prevents the fire-resistant coating 30 from falling off under its own weight as it deteriorates due to heat from a fire.

[0080] In addition, at least one of horizontal reinforcing members 21 and vertical reinforcing members 22 is provided, which can further improve the buckling strength of the fire-resistant coated beam 100.

[0081] In addition, the thickness of the auxiliary material 20 is 6 mm or more. This makes it possible to secure an area for placing pins P or fastening materials F on the side surface of the auxiliary material 20 in the thickness direction that faces the fire-resistant coating 30. Furthermore, the strength added by the auxiliary material 20 to the fire-resistant coated beam 100 can be made necessary and sufficient.

[0082] Furthermore, the auxiliary members 20 are arranged continuously or intermittently in the longitudinal direction X of the beam body 10. Therefore, the form of the auxiliary members 20 can be appropriately selected according to the requirements of the structure to which the fire-resistant coated beam 100 is to be installed. When the auxiliary members 20 are arranged continuously, the number of steel plates used can be minimized. When the auxiliary members 20 are arranged intermittently, the increase in weight of the fire-resistant coated beam 100 due to the auxiliary members 20 can be minimized.

[0083] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the present embodiment, the beam body 10 is described as being an H-shaped steel, but this is not limited thereto. As long as it is possible to arrange the reinforcing members 20 on the web 13, for example, an L-shaped steel, a C-shaped steel, an I-shaped steel, a channel steel, a T-shaped steel, or the like may be appropriately selected and used as needed.

[0084] In addition, within the scope of the spirit of the present invention, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described modifications may be combined as appropriate. [Explanation of symbols]

[0085] 10 Beam body 11 Upper flange 12 Lower flange 13. Web 20 Auxiliary materials 21 Horizontal auxiliary material 22 Vertical support material 30 Fire-resistant coating 31 Spraying material 32 Wrapping material 100 Fireproof coated beam A Air layer F Fastening material P-pin X Longitudinal direction Y width direction Z vertical direction

Claims

1. a beam body having an upper flange, a lower flange, and a web connecting the upper flange and the lower flange; A reinforcing member for the beam body provided on the web; a fire-resistant covering that covers the beam body and the auxiliary material, The fire-resistant coating is a sprayed material, a portion of the fire-resistant coating covering one of the upper flange and the lower flange is stacked in the vertical direction with respect to a surface of the one flange facing the other flange; the auxiliary member is a plate-like member that is disposed closer to the one flange than the other flange and is parallel to the one flange, a first surface of the auxiliary material facing the other flange is disposed at a position aligned with a surface of the fire-resistant coating stacked on the one flange, or is disposed closer to the one flange than the position aligned with the surface of the fire-resistant coating; Fireproof coated beams.

2. In the width direction of the beam body, the dimension of the auxiliary material is 1 / 3 or more and 2 / 3 or less of the covering thickness of the fire-resistant coating, A pin is arranged at the end of the auxiliary member, which is one of the two ends of the auxiliary member in the width direction of the beam body, on the end opposite to the side facing the web, The height of the pin and the dimension of the reinforcing member in the width direction of the beam body are combined to be equal to the covering thickness of the fire-resistant coating on the reinforcing member. The fire-resistant coated beam according to claim 1.

3. The pins are arranged in the width direction of the beam body and along the longitudinal direction of the beam body at a pitch of 500 mm or less. The fire-resistant coated beam according to claim 2.

4. a beam body having an upper flange, a lower flange, and a web connecting the upper flange and the lower flange; A reinforcing member for the beam body provided on the web; a fire-resistant covering that covers the beam body and the auxiliary material, The fire-resistant coating is a sprayed material, In the width direction of the beam body, the dimension of the auxiliary material is 1 / 3 or more and 2 / 3 or less of the covering thickness of the fire-resistant coating, A pin is arranged at the end of the auxiliary member, which is one of the two ends of the auxiliary member in the width direction of the beam body, on the end opposite to the side facing the web, The height of the pin and the dimension of the reinforcing member in the width direction of the beam body are combined to be equal to the covering thickness of the fire-resistant coating on the reinforcing member. Fireproof coated beams.

5. The pins are arranged in the width direction of the beam body and along the longitudinal direction of the beam body at a pitch of 500 mm or less. The fire-resistant coated beam according to claim 4.

6. The reinforcing member is not provided at the longitudinal end of the beam body. A fire-resistant coated beam according to any one of claims 1 to 5.

7. The auxiliary material is A horizontal support member is placed on the web so that a plate-shaped plane is parallel to the upper flange or the lower flange; A vertical support member is arranged on the web so that a plate-shaped plane is perpendicular to the upper flange or the lower flange; comprising at least one of: A fire-resistant coated beam according to any one of claims 1 to 6.

8. the auxiliary member is a plate-shaped member, The thickness of the auxiliary material is 6 mm or more. A fire-resistant coated beam according to any one of claims 1 to 7.

9. The auxiliary members are arranged continuously or intermittently in the longitudinal direction of the beam body. A fire-resistant coated beam according to any one of claims 1 to 8.

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