JP6505270B2 - Fireproof reinforcement method of concrete filled steel pipe column - Google Patents

Description

  The present invention relates to a method of fireproof reinforcement of a concrete-filled steel pipe column.

  A concrete-filled steel pipe (CFT (Concrete Filled Steel Tube)) pillar in which concrete is filled in a steel pipe pillar is known (see, for example, Patent Document 1). Since the CFT column is filled with concrete in the steel pipe column, the CFT column has a large heat capacity and is excellent in fire resistance performance as compared with a hollow steel pipe column. Therefore, depending on the design conditions, it is possible to omit the fireproof coating of the CFT column.

Unexamined-Japanese-Patent No. 10-204993

  By the way, for example, there is a possibility that the fire resistance performance (required fire resistance performance) required of the CFT column may be increased due to a design change or the like.

  An object of the present invention is, in consideration of the above-mentioned facts, to improve the fireproof performance of a concrete-filled steel pipe column.

  The fireproof reinforced structure of a concrete-filled steel pipe column according to the first aspect is a concrete-filled steel pipe column, the fireproof-coated steel frame beam joined to the concrete-filled steel pipe column, and the fireproof-coated steel frame beam And a post-applied fire-resistant covering material to be coated.

  According to the fireproof reinforced structure of the concrete-filled steel pipe column of the first aspect, the fireproof-coated steel frame beam is further fireproof-coated by the post-construction fireproof covering material.

  Here, when the extension length of the steel frame beam in the material axial direction at the time of fire is large, local buckling occurs in the column head and column base of the concrete-filled steel pipe column, and the concrete-filled steel pipe column is structurally stable It may not be possible to hold it. The amount of extension in the axial direction of such a steel frame beam becomes longer as the required fire resistance required for the concrete-filled steel pipe column, that is, the required fire resistance time becomes longer. In other words, if the required fire resistance required for concrete-filled steel pipe columns is high, local buckling of the concrete-filled steel pipe columns is likely to occur locally, and the concrete-filled steel pipe columns can not hold structural stability. There is sex.

  On the other hand, since the required fireproof time is determined by conditions such as the amount of combustibles in the room, the required fireproof time may be longer than the initially set time if there is a design change such as application change or plan change. As a result, the concrete-filled steel pipe column may not be able to meet the required fire performance for the required fire time.

  Therefore, in the present invention, the fireproof-coated steel frame beam is further fireproof-coated with the post-applied fire-resistant covering material. Thereby, the temperature rise of the steel frame beam at the time of a fire is suppressed, and the extension amount of the said steel frame beam in the material axial direction is reduced. As a result, local buckling occurring in the column tops and the like of the concrete-filled steel pipe column is suppressed. Therefore, the fire resistance performance of the concrete-filled steel pipe column is improved.

  In addition, when a fireproof coating is directly applied to a concrete-filled steel pipe column, the cross-sectional area of the concrete-filled steel pipe column including the fireproof coating is increased. On the other hand, in the present invention, the fire resistance performance of the concrete filled steel pipe column is improved without directly applying the fireproof coating to the concrete filled steel pipe column, that is, without increasing the cross sectional area of the concrete filled steel pipe column. be able to.

  The present invention is also effective when it is difficult to provide a concrete-filled steel pipe column with fireproof reinforcement due to reasons such as construction.

  The fire-resistant reinforcing structure of a concrete-filled steel pipe column according to a second aspect is the existing fire-resistant covering according to the first aspect, wherein the post-applied fire-resistant covering material fires over the steel frame beam It is a fireproof covering material different from the material.

  According to the fireproof reinforced structure of the concrete-filled steel pipe column according to the second aspect, the workability can be enhanced by using a fireproof covering material different from the existing fireproof covering material as the post-construction fireproof covering material. For example, a fireproof coating material of a winding system as a post-applied fire resistance coating material or a fire protection coating material of a board system is post-applied from above the sprayed rock wool as fire protection coating material for fire resistance coating of steel frame beams. Is considered.

  The fireproof reinforced structure of a concrete-filled steel pipe column according to a third aspect is the fireproof reinforced structure of the concrete-filled steel pipe column according to the first aspect or the second aspect, wherein the steel frame beam is joined to one side of the concrete filled steel pipe column There is.

  According to the fire-resistant reinforcing structure of the concrete-filled steel pipe column according to the third aspect, in the concrete-filled steel pipe column arranged on the outer periphery of the building, for example, a steel beam in the inter-beam direction is joined to one side of the connection on the column head side Ru. Therefore, the amount of extension of the steel beam in the axial direction of the steel beam becomes larger as compared with the configuration in which a pair of steel beam is joined to both sides of the connection on the column head side of the concrete filled steel tube column. The bending moment acting on the As a result, local buckling is likely to occur in the column head and column base of the concrete-filled steel pipe column.

  In the present invention, the fire resistance performance of the concrete-filled steel pipe column can be efficiently improved by further fire-coating the steel frame beam joined to one side of the concrete-filled steel pipe column as described above with the post-construction fireproof covering material. .

  The fireproof reinforced structure of a concrete-filled steel pipe column according to a fourth aspect is the fireproof reinforced structure of the concrete-filled steel pipe column according to the third aspect, wherein the length in the material axial direction of the steel frame beam is 12 m or more.

  According to the fire-resistant reinforcing structure of the concrete-filled steel pipe column in the fourth aspect, the extension amount of the steel frame beam in the material axial direction at the time of fire increases as the length of the steel frame beam in the material axial direction becomes longer. Therefore, for example, the fire resistance performance of the concrete-filled steel pipe column can be efficiently improved by fire-coating a steel frame beam having a length of 12 m or more in the material axial direction with the post-applied fire-resistant covering material.

  As described above, according to the present invention, the fire resistance performance of the concrete-filled steel pipe column can be improved.

It is a longitudinal cross-sectional view which shows the concrete filling steel pipe column to which the fireproof reinforcement structure of the concrete filling steel pipe column which concerns on one Embodiment of this invention is applied. It is line 2-2 in FIG. 1 sectional drawing. It is an expanded sectional view of FIG. 2 which shows the generation | occurrence | production part of local buckling in the column top of a steel pipe column. It is an elevation view which shows the structure comprised with a general concrete filled steel pipe column and beam, (A) shows the state before a fire, (B) shows the state after a fire. It is a model figure which shows the experimental evaluation model used for fire resistance performance evaluation of a general concrete filled steel pipe column, (A) shows the state before loading of horizontal force, (B) is when horizontal force is loaded. (C) shows a state in which local buckling has occurred in the steel pipe column constituting the concrete-filled steel pipe column. (A) is a cross-sectional view of the column head of the concrete-filled steel pipe column shown in FIG. 1, (B) is a cross section corresponding to FIG. 6 (A) showing a modified example of the concrete-filled steel pipe column shown in FIG. It is a front view. It is sectional drawing corresponded to FIG. 2 which shows the modification of the fireproof reinforcement structure of the concrete filling steel pipe column which concerns on one Embodiment of this invention. It is sectional drawing corresponded to FIG. 2 which shows the modification of the fireproof reinforcement structure of the concrete filling steel pipe column which concerns on one Embodiment of this invention. It is sectional drawing corresponded to FIG. 2 which shows the modification of the fireproof reinforcement structure of the concrete filling steel pipe column which concerns on one Embodiment of this invention.

  Hereinafter, the fireproof reinforcing structure of a concrete-filled steel pipe column according to an embodiment of the present invention will be described with reference to the drawings. In addition, the arrow Z suitably shown in each figure has shown the material axial direction (up-down direction) of the steel pipe column.

  FIG. 1 shows, as an example, an existing concrete-filled steel pipe column 10 to which a fire-resistant reinforced structure (hereinafter simply referred to as "fire-resistant reinforced structure") 30 according to the present embodiment is applied. The concrete-filled steel pipe column 10 includes a steel pipe column 12 and a filled concrete 14 filled in the steel pipe column 12, and is a non-refractory coating not provided with a fireproof coating. The steel pipe column 12 is formed of a square steel pipe and extends between the upper connection 12U and the lower connection 12L as the upper and lower connections 12U and the lower connection 12L and the lower connection 12L. And a steel pipe main body 12B.

  The upper connection 12U is provided with a pair of upper and lower inner diaphragms 18 as a pair of upper and lower diaphragms that reinforce the upper connection 12U. The pair of upper and lower inner diaphragms 18 are formed of a rectangular steel plate in a plan view. The pair of upper and lower inner diaphragms 18 are disposed to face each other in the vertical direction (the material axis direction of the steel pipe column 12), and the outer peripheral portions thereof are joined to the inner side surface of the upper connection 12U by welding or the like. .

  Further, filling holes 18A are respectively formed in the central portions of the respective inner diaphragms 18, and the filling concrete 14 is filled in the steel pipe column 12 through the filling holes 18A. As in the upper connection 12U, a pair of upper and lower inner diaphragms 18 as a pair of upper and lower diaphragms is provided in the lower connection 12L.

  The existing upper steel beam 16 and the lower steel beam 17 as steel beams are joined to one side of the upper connection 12U and the lower connection 12L, respectively. Since the upper steel frame beam 16 and the lower steel frame beam 17 have the same configuration, the configuration of the upper steel frame beam 16 will be described in detail, and the description of the configuration of the lower steel frame beam 17 will be omitted as appropriate.

  The upper steel frame beam 16 is formed of H-shaped steel, and has a pair of upper and lower upper flanges 16A and lower flanges 16B, and a web portion 16C connecting the upper flanges 16A and the lower flange 16B. doing. The end in the material axial direction of the upper steel frame beam 16 pierces the outer surface of the upper connection 12U so that the upper and lower pair of upper flanges 16A and the lower flange 16B are continuous with the upper and lower inner diaphragms 18, respectively. It is applied and joined by welding. Further, a reinforced concrete slab 20 is constructed on the upper steel beam 16. Similar to the upper steel beam 16, the lower steel beam 17 is formed of H-shaped steel, and the upper and lower pair of upper and lower flanges 17A and 17B, and the upper and lower flanges 17A and 17B. And a web unit 17C that connects them.

  As shown in FIG. 2, the upper steel frame beam 16 is fireproof-coated with a blown rock wool 40 as an existing fireproof covering material and a wound-based fireproof covering material 50 as a post-applied fireproof covering material. The sprayed rock wool 40 is constructed according to the required fire resistance performance of the upper steel beam 16 and the concrete-filled steel pipe column 10 when the upper steel beam 16 is newly built, and the upper surface of the upper steel beam 16 is substantially excluded. It covers the whole surface.

  On the other hand, when the fire resistance performance of the concrete-filled steel pipe column 10 becomes high due to a design change (for example, application change, plan change, etc.) after construction of the blowing lock wool 40, the winding-based fireproof covering material 50 The upper steel frame beam 16 is wound from above the sprayed rock wool 40 according to the required fire resistance performance. That is, in order to satisfy the required fire resistance performance of the concrete-filled steel pipe column 10 raised by design change etc., the winding system fire-resistant covering material 50 further adds the upper steel frame beam 16 from above the existing shot rock wool 40 by post construction. Fireproof coating.

  The winding-based fire-resistant covering material 50 is formed of a winding-type fire-resistant covering material formed by molding rock wool or the like into a sheet. The winding-based fire-resistant covering material 50 is bent into a substantially U-shaped cross section with the slab 20 side opened, and is wound around the upper rock beam 16 from the top of the blown rock wool 40. Spaces S are respectively formed between the side portions 50A on both sides of the winding-based fire-resistant covering material 50 and the sprayed rock wool 40. Further, the upper end 50 B of the winding-based refractory covering material 50 is bent outward along the lower surface of the slab 20, and is fixed to the lower surface of the slab 20 by the fixing screw 52. Furthermore, the bottom 50C of the winding-based fire-resistant covering material 50 is fixed to the lower flange 16B of the upper steel frame beam 16 by the fixing pin 54 penetrating the bottom 50C and the blast lock wool 40.

  Next, the operation of the present embodiment will be described.

  As shown in FIG. 1, for example, when the upper steel beam 16 is expanded in the material axial direction (horizontal direction, arrow S direction) due to thermal expansion at the time of fire, a horizontal force F acts on the upper connection 12U and the steel pipe main body A bending moment M is generated in the portion 12B. The bending moment M gradually increases from the intermediate portion 12BM in the material axial direction of the steel pipe main portion 12B toward each of the column head 12BU and the column base 12BL in the material axial direction.

  On the other hand, the steel pipe column 12 expands in the axial direction of the material (arrow Z direction) due to thermal expansion during a fire, but the expansion in the axial direction of the material gradually decreases due to a decrease in rigidity due to temperature rise, reaching a certain temperature As a result, the extensional deformation in the axial direction of the material stops and turns to contraction. In this state, when the horizontal force F acts from the upper steel frame beam 16 to the upper connection 12U, as described above, the column head 12BU and the column of the steel pipe body 12B generate a large bending moment M as compared with the intermediate portion 12BM. The local buckling K is easily generated on the side wall portions 12S1 and 12S2 on the compression side (arrow C side) of the leg portion 12BL. In particular, the column head 12BU is rigidly connected to the upper steel beam 16 via the upper connection 12U, and the column base 12BL is rigidly connected to the lower steel beam 17 via the lower connection 12L, and When the amount of extension (extension amount) of the upper steel frame beam 16 in the axial direction of the material is large, deformation with a large curvature occurs in the column head 12BU and the column base 12BL. If the side walls 12S1 and 12S2 on the compression side (arrow C side) of the column head 12BU and the column base 12BL are generated by this deformation, the side walls 12S1 and 12S2 are displaced outward in the out-of-plane direction Local buckling K occurs.

  When local buckling K occurs in the column head 12BU or the column base 12BL, the bending rigidity of the concrete-filled steel pipe column 10 is significantly reduced. Further, as shown in FIG. 3, in the generation portion of the local buckling K in the column head 12BU, the compression-side sidewall 12S1 of the column head 12BU restraining the filling concrete 14 expands outward, and the filling concrete 14 and A gap W is formed between the side wall 12S1 and the side wall 12S1. As a result, in the local buckling K generation portion, the restraining force (restraint effect) of the side wall portion 12S1 against the filling concrete 14 can not be obtained, and the compression side edge (peripheral portion) 14S of the filling concrete 14 is easily crushed.

  Then, when the compression side edge 14S of the filled concrete 14 is crushed, the axial displacement of the concrete-filled steel pipe column 10 rapidly increases, and the crushing side edge 14S of the filled concrete 14 collapses with the rapid increase of the axial displacement of the material. Further progress may occur, and the concrete-filled steel pipe column 10 may not be able to maintain its structural stability.

  Here, “concrete-filled steel pipe column 10 can not maintain structural stability” means, for example, that the vertical displacement (in the material axis direction) of concrete-filled steel pipe column 10 becomes excessive, or This means that the longitudinal displacement can not be maintained, for example, due to a rapid increase in directional displacement. Moreover, although description is abbreviate | omitted, it is also the same as when the local buckling K generate | occur | produces in the column base part 12BL of the concrete filling steel pipe column 10. FIG.

  Here, the extension amount of the upper steel frame beam 16 in the material axial direction becomes longer as the required fire resistance performance required for the concrete-filled steel pipe column 10, ie, the required fire resistance time becomes longer. Since the required fireproof time is determined by the conditions such as the amount of combustibles in the room, when there is a design change such as a change in indoor use or a plan change, the required fireproof time becomes longer than the time set initially (at the time of new construction) In some cases, the filled steel pipe column 10 can not satisfy the required fire performance for the required fire time. That is, when the required fire resistance performance required for the concrete-filled steel pipe column 10 is increased by design change, local buckling K is easily generated in the column head 12BU and the column base 12BL of the concrete-filled steel pipe column 10, and the concrete-filled steel pipe column 10 may not be able to maintain structural stability.

  On the other hand, in the present embodiment, as shown in FIG. 1 and FIG. 2, the upper surface of the existing blasting rock wool 40 is satisfied so as to satisfy the required fire resistance performance of the concrete-filled steel pipe column 10 raised by design change or the like. The upper steel frame beam 16 is further refractory-coated by the winding-based refractory coating material 50 from the above. Thereby, the temperature rise of the upper steel frame beam 16 at the time of fire is further suppressed, and the extension amount of the upper steel frame beam 16 in the material axial direction is reduced. As a result, local buckling K generated on the compression-side side wall portions 12S1 and 12S2 of the column head 12BU and the column base 12BL is suppressed. Therefore, the fire resistance performance of the concrete-filled steel pipe column 10 is improved.

  In addition, it is conceivable that the concrete-filled steel pipe column 10 is directly fireproofed with a fireproof covering material such as spray lock wool or a winding-based fireproof covering material to enhance the fireproof performance of the concrete-filled steel pipe column 10. The cross-sectional area of the concrete-filled steel pipe column 10 including the fireproof covering material is increased.

  On the other hand, in the present embodiment, the fire resistance performance of the concrete-filled steel pipe column 10 is achieved by fire-resistantly coating the upper steel frame beam 16 with the winding-based fire-resistant covering material 50 without directly covering the concrete-filled steel pipe column 10. Indirectly. Therefore, the fire resistance performance of the concrete-filled steel pipe column 10 can be enhanced without increasing the cross-sectional area of the concrete-filled steel pipe column 10. Furthermore, this embodiment is effective also when it is difficult to fireproof coat the concrete-filled steel pipe column 10 directly due to reasons such as construction.

  Furthermore, the upper steel frame beam 16 can be easily refractory-coated by using a winding-based refractory-covering material 50 different from the existing spray lock wool 40 as a post-applied fire-resistant coating material. Therefore, the workability is improved.

  Here, FIG. 4 (A) shows an example of a frame composed of a column 100 made of a general concrete-filled steel pipe column and beams 102A and 102B. In this frame, for example, as shown in FIG. 4B, when a fire 104 occurs, the beam 102A extends in the axial direction of the material (the direction of the arrow J). It occurs.

  Further, FIG. 5A shows an experimental evaluation model used to evaluate the fire resistance performance of a column 110 made of a general concrete-filled steel pipe column. In this experimental evaluation model, since the deformed state and the stressed state as shown in FIG. 5B are shown during heating, the deformed state and the stressed state of the column 100 shown in FIG. 4B are appropriately simulated. It is said that you can do it. Then, when the loading heating experiment was performed using the experimental evaluation model shown in FIG. 5A, new findings shown below were obtained.

  That is, as shown in FIG. 5C, when horizontal displacement (horizontal force F) generated at the upper end of the heated column 110 is large or when axial force (long-term axial force) V generated in the column 110 is large. It was confirmed that local buckling K occurs in the column head and column base of the steel pipe column constituting the column 110. In addition, even if the heating time is relatively short and the filled concrete of the column 110 has sufficient strength, the column 110 loses its load bearing ability due to the local buckling K of the column head and column base described above. It was confirmed that the structural stability could not be maintained.

  It is known that the local buckling K is more likely to occur as the amount of extension of the upper steel beam 16 in the material axial direction is larger, in other words, as the beam length of the upper steel beam 16 becomes longer.

  Here, for example, as shown in FIG. 6A, the upper steel beam 16 (hereinafter referred to as “upper steel frame”) is provided on both sides in the arrow Y direction (column direction) of the upper connection 12U of the steel pipe column 12 When the beam 16Y is connected and the upper steel beam 16 (hereinafter referred to as “upper steel beam 16X”) is connected to only one side of the upper connection 12U in the arrow X direction (inter-beam direction), The upper steel beam 16Y in the arrow Y direction (column direction) does not have a long beam length, and it is general to plan the beam length of the upper steel beam 16X in the arrow X direction (inter-beam direction). There is a high possibility that local buckling K will occur on the compression-side sidewall 12S1 of the portion 12BU.

  When a plurality of upper steel frame beams 16X and 16Y are joined to the upper joint section 12U from two horizontal directions, the existing upper steel frame beam 16X joined to one side of the upper joint section 12U is further wound around the system. By performing fireproof coating with the covering material 50, it is possible to efficiently suppress the local buckling K generated in the column top 12BU and the column base 12BL of the steel pipe main body 12B.

In particular, when the axial length (beam span) of the upper steel beam 16X joined to the upper joint 12U on one side increases, the amount of extension of the upper steel beam 16X during a fire increases, and the steel pipe main body 12B The horizontal displacement (forced deformation) of the column head 12BU may increase.
For example, when the temperature of the upper steel beam 16X at the time of fire is 500 ° C., and the column length of the concrete-filled steel pipe column 10 (the length of the steel pipe main portion 12B in the material axial direction) is 4 m, the material shaft of the upper steel beam 16X When the length in the direction is 12 m or more, the member angle of the concrete-filled steel pipe column 10 is likely to be 1/50 rad or more. The amount of extension of the upper steel frame beam 16X in the axial direction of the material is calculated by taking into consideration the influence of the extension of the upper steel beam 16Y on the assumption that the upper steel beam 16X freely expands at 12 μ / ° C. . Therefore, the fire resistance performance of the concrete-filled steel pipe column 10 can be efficiently improved by further covering the upper steel frame beam 16X having a length of 12 m or more in the material axial direction with the fireproof covering material 50 by fire protection.

  Further, as shown in FIG. 6B, in the case where the upper steel frame beams 16X and 16Y are joined to only one side of the upper connection 12U in any direction of the arrow X direction and the arrow Y direction, as shown in FIG. Since the extension amount of the steel frame beam 16Y is also increased, each of the upper steel frame beams 16X and 16Y may be further wound with a fireproof covering material 50 by winding. In addition, as a column (concrete filled steel pipe column 10) in which the upper steel frame beam 16 is joined to one side of the upper connection 12U, an outer column of a structure or an inner column surrounding a blow through may be mentioned.

  Next, modifications of the above embodiment will be described.

  In the above embodiment, an example was shown in which the upper steel frame beam 16 was further fire-clad from the top of the spray lock wool 40 as the existing fire-resistant covering material by the winding-based fire-resistant covering material 50 as the post-applied fire-resistant covering material. Not exclusively. The combination of the existing fire-resistant covering material and the post-applied fire-resistant covering material can be changed appropriately.

  For example, in the modification shown in FIG. 7, a fireproof paint 42 is used as the existing fireproof covering material. The fireproof paint 42 is applied to substantially the entire surface of the upper steel frame beam 16 except for the upper surface thereof. From the top of the fireproof paint 42, a winding-based fireproof covering material 50 is wound around the upper steel frame beam 16 by post-construction. That is, on the existing fireproof paint 42, the upper steel beam 16 is further fireproof coated with a winding-based fireproof covering material 50 different from the fireproof paint 42 concerned.

  For example, in the modification shown in Drawing 8, winding system fireproof covering material 44 is used as an existing fireproof covering material. The winding-based fire-resistant covering material 44 has the same structure as the winding-based fire-resistant covering material 50, and the upper end 44B bent outward along the lower surface of the slab 20 is fixed to the lower surface of the slab 20 by fixing screws 52. ing. A space S is formed between the side portions 44A on both sides of the winding-based fire-resistant covering material 44 and the web portion 16C of the upper steel frame beam 16, respectively.

  A winding-based fire-resistant covering material 50 of the same type as the winding-based fire-resistant covering material 44 is wound around the upper steel frame beam 16 from above the winding-based fire-resistant covering material 44 by post-construction. That is, on the existing winding-based fireproof covering material 44, the upper steel frame beam 16 is further fireproof-coated with the same winding-based fireproof covering material 50 as the winding-based fireproof covering material 44. Thus, it is also possible to use the same kind of fireproof coating material as the existing fireproof coating material and the post-construction fireproof coating material. The bottom portion 50C of the winding-based fire-resistant covering material 50 is fixed to the lower flange portion 16B of the upper steel frame beam 16 by the fixing pin 54 penetrating the bottom 50C and the bottom 44C of the winding-based fire-resistant covering material 44.

  Furthermore, it is also possible to remove a part of the existing fireproof covering at the time of construction of the post-applied fireproof covering. For example, in the modification shown in FIG. 9, a part (a part shown by a two-dot chain line) of the blown rock wool 40 as the existing fireproof covering material is removed.

  Specifically, the cover 40A of the blow lock wool 40 covering the lower surface of the lower flange 16B of the upper steel frame beam 16, and the end in the width direction of the upper flange 16A and the lower flange 16B. The four coating portions 40B of the blown rock wool 40 in the above are removed. A winding-based fire-resistant covering material 50 is wound around the upper steel frame beam 16 from above the sprayed rock wool 40 from which the covering portions 40A and 40B have been removed as described above. Therefore, for example, the lower surface of the lower flange portion 16B of the upper steel frame beam 16 from which the covering portion 40A is removed is directly fireproof-coated by the winding-based fireproof covering material 50.

  By removing the coating portions 40A and 40B of the spray lock wool 40 in this manner, the winding-based fireproof coating 50 can be easily wound around the upper steel frame beam 16 from above the spray lock wool 40. Therefore, the workability of the winding-based fireproof covering material 50 is improved.

  Moreover, as the existing fireproof coating material and the post-construction fireproof coating material, for example, not only the above-mentioned spray rock wool 40 and winding system fireproof coating material 50 but also spray system fireproof coating materials other than spray lock wool 40, board systems A fireproof covering material such as a fireproof covering material and a fireproof paint can be used. In addition, spray-type fire-resistant coating materials other than spray lock wool here mean wet-spray lock wool, gypsum-based wet-spray fire-resistant coating, ceramic-based wet fire-resistant coating, and the like. Moreover, with a board-based fire-resistant covering material, for example, gypsum board (including reinforced gypsum board), calcium silicate board mixed with fiber, mortar board, rock wool board, ceramic fiber board, PC board, ALC panel, extrusion-molded cement board Means etc. Furthermore, for the existing fireproof covering material and the post-applied fireproof covering material, the same kind of fireproof covering material may be used as described above, or different kinds of fireproof covering material may be used.

  Moreover, although the example which formed the steel pipe column 12 by the square steel pipe was shown in the said embodiment, it does not restrict to this. The steel pipe column may be, for example, a square steel pipe having a substantially rectangular cross section, or a round steel pipe having a circular cross section.

  Moreover, although the example which made the concrete filling steel pipe column 10 non-refractory coating was shown in the said embodiment, you may provide fire resistance coating also by the post construction also to the concrete filling steel pipe column 10 as needed.

  Moreover, in the said embodiment, although the inner diaphragm 18 was demonstrated to an example as a pair of upper and lower diaphragm, it does not restrict to this. As a pair of upper and lower diaphragms, for example, a through diaphragm or an outer diaphragm may be used. Furthermore, the steel pipe column 12 may be provided with a fireproof coating as needed.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to such Embodiment, You may use it combining suitably one Embodiment and various modifications, The summary of this invention Of course, various modifications can be made without departing from the scope of the invention.

10 Concrete Filled Steel Tubular Column 16 Upper Steel Beam (Steel Beam)
30 Fireproof reinforcement structure of concrete filled steel pipe column 40 Spray rock wool (existing fireproof covering material)
42 Fireproof paint (existing fireproof covering material)
44 Winding-based fireproof covering (existing fireproof covering)
50 Wrapping fire-resistant covering material (post-applied fire-resistant covering material)

Claims (1)

Together are joined to a concrete filled tubular column, when the refractory coated steel beam in resistant fire dressing when new, requested fire resistance required for the concrete-filled steel tube column is higher, from the top of the refractory coating material Further fire-resistant coating with a post-applied fire- resistant coating material of the same type as the fire-resistant coating material,
Fireproof reinforcement method of concrete filled steel pipe column.