A simplified alternative test method for fire resistance testing of wrapped steel columns

Abstract

The present invention discloses a simplified alternative test method for a fire resistance test of a sheathed protected steel column, the specific steps of which include simplifying an original test object column specimen into an alternative specimen; conducting a fire resistance test on the simplified alternative specimen; placing the alternative specimen in a test device, the test device being capable of providing a rectangular single-sided fire environment for an alternative fire-exposed surface of the alternative specimen, and all outer surfaces of the alternative specimen except the alternative fire-exposed surface being in an insulating environment; the present invention simplifies the column specimen into an alternative specimen that can be applied to an alternative test furnace, and the alternative test device can be of any size, thereby facilitating downsizing the test scale and reducing the test cost; at the same time, the present invention changes the four-sided fire requirement of the column specimen into a single-sided fire requirement of the alternative specimen, facilitating realization of the specimen fire requirement under conditions of a small-volume heating chamber; the alternative specimen can perform one-dimensional temperature field calculation along the thickness direction, thereby realizing rapid inspection of the fire temperature rise and fire resistance limit of the sheathed protected steel column.

Description

Technical Field

[0001] The present invention relates to the field of fire resistance test of wrapped protective steel columns, and in particular to a simplified alternative test method for fire resistance test of wrapped protective steel columns. Background Art

[0002] Steel columns, with their advantages of being lightweight, high-strength, recyclable, and earthquake-resistant, have been widely used in residential and commercial buildings. However, due to steel's high thermal conductivity, fire resistance is a weak link in steel structures. Therefore, steel columns often require fire protection measures, such as cladding. This involves evenly coating the steel column with fireproofing materials (such as fireproof panels and fireproof felt), effectively enhancing the steel column's fire resistance.

[0003] Conducting full-scale model fire resistance tests on column components is a common method for verifying their fire resistance performance. The "Fire Resistance Test Methods for Building Components Part 3: Test Methods and Notes on the Application of Test Data" recommends a minimum standard height of 3000mm for column specimens. Therefore, the heating height of large-scale fire resistance test systems used to conduct column specimens generally exceeds 3000mm. This results in a large volume and mass of large-scale fire resistance test systems, requiring a larger test space to store the equipment, leading to high equipment costs and significant energy consumption.

[0004] In addition, in order to meet the power requirements of large-scale fire resistance test systems, the test site often also needs to be equipped with a 380V voltage high-power circuit. Summary of the Invention

[0005] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide an alternative simplified test method for the fire resistance test of coated protective steel columns.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The present invention provides a simplified alternative test method for fire resistance test of wrapped protective steel columns.

[0008] The following steps are involved:

[0009] Step S1, simplifying the original test object column specimen into a replacement specimen;

[0010] The four sides of the column specimen in contact with the fire environment are the fire-exposed surfaces. From the outside to the inside of the fire-exposed side, the column specimen includes the encapsulated protective layer and the steel column;

[0011] The specific steps are:

[0012] Step S11:

[0013] The central symmetry line of the cross section of the column specimen is extended along the height direction to form a central symmetry plane;

[0014] The column specimen is cut along the central symmetric plane into four angular sub-columns, that is, the fire-exposed surface is divided into four fire-exposed angular surfaces, the wrapped protective layer is divided into four angular sub-protective layers, and the steel column is divided into four angular sub-steel columns;

[0015] Step S12:

[0016] For any angular column, expand its fire-affected angle surface to form a fire-affected surface;

[0017] The angular protective layer and the angular steel column are simplified into rectangular protective layer and rectangular steel column respectively according to the principle of the same volume, height and thickness;

[0018] After simplification, each angular column becomes a tower column, which includes a fire-bearing surface, a rectangular protective layer and a rectangular steel column from the outside to the inside in the fire environment;

[0019] Step S13:

[0020] According to the principle that the height of the tower column is the same as the length of one side of the replacement fire surface,

[0021] According to the principle that the length of the fire-exposed surface is the same as the length of the other side that replaces the fire-exposed surface,

[0022] According to the principle that the length ratio of the fire-exposed surface, the rectangular protective layer and the rectangular steel column remains unchanged,

[0023] According to the principle that the thickness of the fire-exposed surface, the thickness of the rectangular protective layer and the thickness of the rectangular steel column remain unchanged, the tower-shaped column is simplified into a tower-shaped substitute specimen;

[0024] Step S2: performing a fire resistance test on the simplified alternative specimen;

[0025] The specific steps are:

[0026] The substitute test piece is placed in a test device that can provide a rectangular single-sided fire environment for the substitute fire surface of the substitute test piece. The remaining outer surfaces of the substitute test piece except the substitute fire surface are all in an insulating environment.

[0027] The present invention also provides a fire resistance test system using the above-mentioned simplified method. The test equipment is a test furnace, which is provided with a specimen placement cavity and a heating cavity arranged vertically. The alternative specimen is arranged in the specimen placement cavity and its alternative fire-exposed surface faces the heating cavity. The specimen placement cavity is filled with insulating felt for wrapping the remaining outer surface of the alternative specimen.

[0028] Preferably, the cross-sections of the specimen placement cavity and the heating cavity are rectangular, and the cross-section of the specimen placement cavity is larger than the cross-section of the heating cavity.

[0029] Preferably, a thin iron sheet is placed on the step formed between the specimen placement cavity and the heating cavity, the alternative specimen is arranged on the thin iron sheet, and the thin iron sheet is provided with a through hole adapted to the upper port of the heating cavity and the alternative fire-receiving surface.

[0030] Preferably, the thermal insulation felt is made of high-oxygen silica aerogel felt.

[0031] Preferably, the temperature rise requirement of the alternative test is the same as the temperature rise requirement of the existing fire resistance test of the wrapped protective steel column.

[0032] The beneficial effects of the present invention are:

[0033] 1. The present invention simplifies the column specimen into an alternative specimen that can be used to replace the test furnace, and the alternative test equipment can be of any size. Therefore, by reducing the size of the alternative test equipment, the equipment investment can be reduced, the requirements for the test site and supporting facilities can be reduced, the scale of the fire resistance test can be reduced, and the consumables and costs of the test can be reduced.

[0034] 2. The present invention changes the four-sided fire-exposure requirement of the column specimen into the single-sided fire-exposure requirement of the replacement specimen, thereby facilitating the realization of the specimen fire-exposure requirement under the condition of a small-volume heating chamber.

[0035] 3. For column specimens exposed to fire on all sides, the heat transfer path is mainly along the thickness direction. The present invention actually takes into account the thermal insulation capacity of the enveloping protection in the thickness direction, the heat storage capacity of the steel column, and the volume ratio of each part of the column specimen to provide a simplified method. This simplified method can also be used for components with other one-dimensional heat transfer paths after simple changes, such as walls exposed to fire on one or both sides.

[0036] 4. The alternative test piece of the present invention can perform one-dimensional temperature field calculation along the thickness direction, and then combine the critical temperature method of the "Technical Code for Fire Protection of Building Steel Structures" to achieve rapid testing of the fire temperature rise and fire resistance limit of the wrapped protective steel column. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 A structural diagram of a column specimen under a four-sided fire environment in the prior art provided by an embodiment of the present invention;

[0039] Figure 2 A test diagram of an alternative test piece provided by an embodiment of the present invention in a test furnace;

[0040] Figure 3 A simplified schematic diagram of step S11 provided in an embodiment of the present invention;

[0041] Figure 4 A simplified schematic diagram of step S12 provided in an embodiment of the present invention;

[0042] Figure 5 This is a simplified schematic diagram of step S13 provided in an embodiment of the present invention.

[0043] Description of reference numerals:

[0044] 1. Column specimen, 1-1. Fire-exposed surface, 1-2. Encapsulated protective layer, 1-3. Steel column, 3. Alternative specimen, 3-1. Alternative fire-exposed surface, 3-2. Thin iron sheet, 4. Test furnace, 4-1. Specimen placement cavity, 4-2. Heating cavity, 5. Single-sided fire environment, 6. Central symmetry surface, 7. Angular sub-column, 7-1. Fire-exposed angle surface, 7-2. Angular sub-protective layer, 7-3. Angular sub-steel column, 8. Tower-shaped sub-column, 8-1. Fire-exposed surface, 8-2. Rectangular sub-protective layer, 8-3. Rectangular sub-steel column, 9. Insulation felt. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0046] like Figures 1 to 5 As shown in Figure 1, an alternative simplified test method for fire resistance test of wrapped protective steel columns is

[0047] The following steps are involved:

[0048] Step S1, simplifying the original test object column specimen 1 into a replacement specimen 3;

[0049] The four sides of the column specimen 1 in contact with the fire environment are fire surfaces 1-1. From the outside to the inside of the fire side, the column specimen 1 includes a wrapping protective layer 1-2 and a steel column 1-3;

[0050] The specific steps are:

[0051] Step S11:

[0052] The central symmetry line of the cross section of the column specimen 1 is extended in the height direction to form a central symmetry plane 6;

[0053] The column specimen 1 is cut along the central symmetric plane 6 into four angular sub-columns 7, that is, the fire-exposed surface 1-1 is divided into four fire-exposed angular surfaces 7-1, the wrapped protective layer 1-2 is divided into four angular sub-protective layers 7-2, and the steel column 1-3 is divided into four angular sub-steel columns 7-3;

[0054] Step S12:

[0055] For any angular column 7, its fire-sensitive angle surface 7-1 is expanded to form a fire-sensitive surface 8-1;

[0056] The angular sub-protection layer 7-2 and the angular sub-steel column 7-3 are simplified into the rectangular sub-protection layer 8-2 and the rectangular sub-steel column 8-3 respectively in the middle according to the principle of the same volume, height and thickness;

[0057] After simplification, each angular column 7 is transformed into a tower column 8. The tower column 8 includes a fire surface 8-1, a rectangular protective layer 8-2 and a rectangular steel column 8-3 from the outside to the inside in the fire environment.

[0058] Step S13:

[0059] According to the principle that the height of the tower column 8 is the same as the length of one side of the replacement fire surface 3-1,

[0060] According to the principle that the length of the fire-exposed surface 8-1 is the same as the length of the other side that replaces the fire-exposed surface 3-1,

[0061] According to the principle that the length ratio of the fire-exposed surface 8-1, the rectangular protective layer 8-2 and the rectangular steel column 8-3 remains unchanged,

[0062] According to the principle that the thickness of the fire-exposed surface 8-1, the thickness of the rectangular protective layer 8-2, and the thickness of the rectangular steel column 8-3 remain unchanged, the tower-shaped column 8 is simplified into a tower-shaped alternative specimen 3;

[0063] Step S2: performing a fire resistance test on the simplified alternative specimen 3;

[0064] The specific steps are:

[0065] The alternative test piece 3 is placed in a test device that can provide a rectangular single-sided fire environment 5 for the alternative fire surface 3-1 of the alternative test piece 3. The remaining outer surfaces of the alternative test piece 3 except the alternative fire surface 3-1 are all in an insulating environment.

[0066] The present invention also provides a fire resistance test system using the simplified method described above, wherein the test equipment uses a test furnace 4, wherein the test furnace 4 is provided with a specimen placement cavity 4-1 and a heating cavity 4-2 arranged vertically. The alternative specimen 3 is arranged in the specimen placement cavity 4-1 and its alternative fire-receiving surface 3-1 faces the heating cavity 4-2. The specimen placement cavity 4-1 is filled with an insulating felt 9 for wrapping the remaining outer surface of the alternative specimen 3.

[0067] The cross-sections of the specimen placement chamber 4 - 1 and the heating chamber 4 - 2 are rectangular, and the cross-section of the specimen placement chamber 4 - 1 is larger than that of the heating chamber 4 - 2 .

[0068] A thin iron sheet 3-2 is placed on the step formed between the specimen placement cavity 4-1 and the heating cavity 4-2. The alternative specimen 3 is placed on the thin iron sheet 3-2. The thin iron sheet 3-2 has a through hole that matches the upper port of the heating cavity 4-2 and replaces the fire surface 3-1.

[0069] The thermal insulation felt 9 is made of high-oxygen silica aerogel felt.

[0070] The temperature rise requirements of the alternative test are the same as the temperature rise requirements of the existing fire resistance test of the wrapped protective steel column.

[0071] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A simplified alternative test method for fire resistance test of wrapped protective steel columns, characterized in that: The following steps are involved: Step S1, simplifying the original test object column specimen (1) into a replacement specimen (3); The four sides of the column specimen (1) in contact with the fire environment are fire-exposed surfaces (1-1), and the column specimen (1) includes a wrapping protective layer (1-2) and a steel column (1-3) from the outside to the inside of the fire-exposed side; The specific steps are: Step S11: Extending the cross-sectional center symmetry line of the column specimen (1) in the height direction to form a center symmetry plane (6); The column specimen (1) is cut along the central symmetry plane (6) into four angular sub-columns (7), that is, the fire-exposed surface (1-1) is divided into four fire-exposed angular surfaces (7-1), the encapsulated protective layer (1-2) is divided into four angular sub-protective layers (7-2), and the steel column (1-3) is divided into four angular sub-steel columns (7-3); Step S12: For any angular column (7), its fire-sensitive angle surface (7-1) is expanded to form a fire-sensitive surface (8-1); The angular sub-protection layer (7-2) and the angular sub-steel column (7-3) are simplified into the rectangular sub-protection layer (8-2) and the rectangular sub-steel column (8-3) respectively in the middle according to the principle of the same volume, height and thickness; The simplified angular sub-columns (7) are transformed into tower-shaped sub-columns (8), and the tower-shaped sub-columns (8) include, from the outside to the inside, a fire-exposed sub-face (8-1), a rectangular sub-protection layer (8-2), and a rectangular sub-steel column (8-3). Step S13: According to the principle that the height of the tower column (8) is the same as the length of one side of the replacement fire surface (3-1), According to the principle that the length of the fire-exposed surface (8-1) is the same as the length of the other side that replaces the fire-exposed surface (3-1), According to the principle that the length ratio of the fire-exposed surface (8-1), the rectangular protective layer (8-2) and the rectangular steel column (8-3) remains unchanged, According to the principle that the thickness of the fire-exposed surface (8-1), the thickness of the rectangular protective layer (8-2) and the thickness of the rectangular steel column (8-3) remain unchanged, the tower-shaped column (8) is simplified into a tower-shaped substitute specimen (3); Step S2: performing a fire resistance test on the simplified alternative specimen (3); The specific steps are: The replacement test piece (3) is placed in a test device, which can provide a rectangular single-sided fire environment (5) for the replacement fire surface (3-1) of the replacement test piece (3), and the remaining outer surfaces of the replacement test piece (3) except the replacement fire surface (3-1) are all in an insulating environment.

2. A fire resistance test system using the simplified method according to claim 1, characterized in that: The test equipment uses a test furnace (4), wherein the test furnace (4) is provided with a test piece placement cavity (4-1) and a heating cavity (4-2) arranged vertically. The substitute test piece (3) is arranged in the test piece placement cavity (4-1) with its substitute fire-receiving surface (3-1) facing the heating cavity (4-2). The test piece placement cavity (4-1) is filled with a heat-insulating felt (9) for wrapping the remaining outer surface of the substitute test piece (3).

3. The fire resistance test system according to claim 2, characterized in that: The cross-sections of the specimen placement cavity (4-1) and the heating cavity (4-2) are rectangular, and the cross-section of the specimen placement cavity (4-1) is larger than the cross-section of the heating cavity (4-2).

4. The fire resistance test system according to claim 2, characterized in that: A thin iron sheet (3-2) is placed on a step formed between the test piece placement cavity (4-1) and the heating cavity (4-2); the replacement test piece (3) is arranged on the thin iron sheet (3-2); and a through hole is opened on the thin iron sheet (3-2) that is adapted to the upper port of the heating cavity (4-2) and the replacement fire-receiving surface (3-1).

5. The fire resistance test system according to claim 2, characterized in that: The thermal insulation felt (9) is made of high-oxygen silicon aerogel felt.

6. The fire resistance test system according to claim 2, characterized in that: The temperature rise requirements of the alternative test are the same as the temperature rise requirements of the existing fire resistance test of the wrapped protective steel column.

Images