Method and device for calculating fire endurance of tenon-and-mortise connection wood framework and medium

Abstract

The invention relates to a method, equipment and medium for calculating the fire endurance of a tenon-and-mortise connection wood framework, and the method comprises the following steps: calculating the effective heat conductivity coefficient of a fireproof coating according to the dense heat conductivity coefficient, porosity and expansion multiple information of the intumescent fireproof coating at different temperatures; taking the fireproof coating layer and the wood component section as a multilayer composite material, and calculating a section composite heat conductivity coefficient and a reduction coefficient of the section relative to a wood heat conductivity coefficient; wood heat conductivity coefficient reduction coefficients in the width direction and the height direction of the section are calculated; the section of the wood component coated with the fireproof coating is equivalent to the section of the wood component not coated with the fireproof coating, and the equivalent section size is calculated; and substituting the equivalent section size into a fire resistance limit calculation expression of the tenon-and-mortise connection wood framework without considering the fire retardant coating to obtain the fire resistance limit of the tenon-and-mortise connection wood framework coated with the intumescent fire retardant coating. Compared with the prior art, the method can realize prediction of the fire endurance and the damage mode of the tenon-and-mortise connection wood framework coated with the fireproof coating.

Description

Technical Field

[0001] This invention relates to civil engineering and related fields, and in particular to a method, equipment, and medium for calculating the fire resistance limit of mortise and tenon joint timber frames. Background Technology

[0002] Timber structures have poor fire resistance, and traditional timber structures pose numerous fire hazards. Therefore, calculating the fire resistance limit of mortise and tenon joint timber frames is of great significance.

[0003] A search revealed Chinese invention patent application CN106529068A, which discloses a fire-resistant design method for glued laminated timber columns considering the strength degradation of wood in the medium and low temperature range. This method considers the temperature distribution of the cross-section of the glued laminated timber column during fire exposure and combines it with a simplified multi-step model of the relative compressive strength of wood along the grain at high temperatures to achieve an economical and reliable fire-resistant design for glued laminated timber columns. However, the above solution focuses on the fire-resistant design of glued laminated timber columns and does not mention the calculation of the fire resistance limit of mortise and tenon joint timber frames.

[0004] Applying fire-retardant coatings is one of the most practical measures to improve the fire safety of traditional wood structures. However, there is a lack of quantitative research on the protective effect of fire-retardant coatings on wood structures. The performance parameters of fire-retardant coatings are not linked to the fire resistance of the structure, and the improvement effect of fire-retardant coatings on the fire resistance of the structure cannot be intuitively reflected. In engineering practice, it is difficult to control the amount of fire-retardant coating used. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects of the prior art by providing a method, equipment and medium for calculating the fire resistance limit of mortise and tenon joint timber frames, which can predict the fire resistance limit and failure mode of mortise and tenon joint timber frames after applying fire-retardant coating.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] According to a first aspect of the present invention, a method for calculating the fire resistance limit of a mortise and tenon joint timber frame is provided, comprising:

[0008] Based on the information on the dense thermal conductivity, porosity, and expansion ratio of intumescent fire-retardant coatings at different temperatures, the effective thermal conductivity λ of the fire-retardant coatings was calculated. s ;

[0009] Treating the fire-retardant coating layer and the cross-section of the wooden component as a multi-layer composite material, based on the effective thermal conductivity λ of the fire-retardant coating... s The composite thermal conductivity λ of the cross section is calculated using Fourier's law of thermal conduction and the principle of series thermal resistance. c And the reduction factor η of the cross section relative to the thermal conductivity of wood;

[0010] The reduction factor η is obtained by weighting the temperature time history curves before the failure temperature of the fire-retardant coating, thus obtaining the reduction factors η of the wood thermal conductivity in the width and height directions of the cross section. B and η H ;

[0011] The cross-section of a fire-retardant wooden component is equivalent to a larger cross-section of an un-fire-retardant wooden component. The equivalent cross-sectional dimensions are calculated based on the reduction factor of the thermal conductivity of wood in the width and height directions.

[0012] By substituting the equivalent cross-sectional dimensions into the fire resistance limit calculation expression for mortise and tenon joint timber frames without considering fire retardant coating, the fire resistance limit of mortise and tenon joint timber frames after applying intumescent fire retardant coating is calculated.

[0013] Preferably, based on the information of the dense thermal conductivity, porosity and expansion ratio of the intumescent fire retardant coating at different temperatures, and based on the assumption of uniform distribution of pores inside the expanded fire retardant coating, the effective thermal conductivity of the fire retardant coating is calculated.

[0014] Preferably, the fire-retardant coating has a thermal conductivity λ s The calculation expression is:

[0015]

[0016] In the formula: λ s and λ g ε represents the actual thermal conductivity of the fire-retardant coating in a dense, non-porous state and air, respectively; ε is the porosity of the fire-retardant coating; and m is the expansion ratio of the fire-retardant coating.

[0017] Preferably, the calculation of the composite thermal conductivity λ of the cross section using Fourier's law of thermal conductivity and the principle of series thermal resistance is... c The calculation expression is:

[0018]

[0019] In the formula: B and H are the width and height of the wooden beam cross-section, respectively; b is the initial dry film thickness of the fire-retardant coating; λ w λ is the thermal conductivity of wood. e The effective thermal conductivity of the fire-retardant coating.

[0020] Preferably, the initial thickness b of the fire-retardant coating dry film is the mass increment of the fire-retardant coating after it has dried completely on the substrate, divided by the density of the fire-retardant coating dry film.

[0021] Preferably, the reduction factor η of the cross section relative to the thermal conductivity of wood is calculated as follows:

[0022]

[0023] In the formula: λ w The thermal conductivity of the material.

[0024] Preferably, the reduction factor η based on the thermal conductivity of wood in the width and height directions of the cross-section is... B and η H The equivalent cross-sectional dimensions are calculated, where the width of the equivalent cross-section is B / η. B The height of the equivalent cross section is H / η H B and H are the width and height of the wooden beam cross-section, respectively.

[0025] Preferably, the formula for calculating the fire resistance limit of the mortise and tenon joint timber frame without considering fire-retardant coating is:

[0026]

[0027] t m =min(T) b ,T j (6)

[0028] In the formula: R is the load-bearing ratio; B and H are the width and height of the timber beam section, respectively; η B η H β0 represents the thermal conductivity reduction factor of wood in the width and height directions, respectively; β0 is the carbonization rate of wood without fire retardant coating; T0 b T j The fire resistance ratings of the beam and the joint, respectively; t m This refers to the fire resistance limit of the timber frame.

[0029] According to a second aspect of the present invention, an electronic device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the program to implement any of the methods described above.

[0030] According to a third aspect of the invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements any of the methods described herein.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) This invention introduces the performance parameters of intumescent fire retardant coatings at different temperatures, such as the thermal conductivity, porosity and expansion ratio, into the calculation of the fire resistance limit of timber frames. This can provide a reference for determining the amount of fire retardant coating in the fire-resistant design of timber structures. By transforming the decrease in the thermal conductivity of the component cross-section after applying the fire retardant coating into the increase in the cross-sectional size, that is, by equating the cross-section of the fire retardant coated timber component with the cross-section of the uncoated timber component, the fire resistance limit of the tenon-and-mortise connected timber frame after applying the intumescent fire retardant coating can be directly solved. There is no need to perform complex numerical simulation calculations. It does not depend on the measured value of the wood carbonization rate. The fire resistance limit and failure mode of the tenon-and-mortise connected timber frame after applying the fire retardant coating can be predicted through equivalent transformation, making the calculation simpler.

[0033] (2) The calculation of the fire resistance limit of the mortise and tenon joint wooden frame after applying the intumescent fire retardant coating can be updated with the update of the calculation method of the fire resistance limit of the wooden frame without fire retardant coating, and has higher universality. Attached Figure Description

[0034] Figure 1 This is a flowchart of the method of the present invention.

[0035] Figure 2 The diagram shows the equivalent calculation process in the embodiment; where (1) to (4) correspond to the cross section of the wooden component and the expanded fireproof coating, the cross section of the wooden component and the equivalent fireproof coating, the composite cross section of the wood and the fireproof coating, and the equivalent cross section of the wooden component without fireproof coating, respectively.

[0036] Figure 3 To consider both normal thermal boundary conditions and heat conduction alone, temperature field simulations were performed on a wooden beam exposed to fire on three sides under standard heating conditions. The carbonization rates of the wood were compared under the two conditions to verify the rationality of neglecting thermal radiation and heat convection in the theoretical derivation of this invention.

[0037] Figure 4 This is a schematic diagram of the dimensions of the mortise and tenon joint wooden frame designed in the embodiment.

[0038] Figure 5 The example uses a linear fitting model to show the change in thermal conductivity of the fire-retardant coating with temperature.

[0039] Figure 6 This is a schematic diagram of the weighted averaging process of the wood thermal conductivity reduction factor η in the embodiment. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0041] Example

[0042] like Figure 1 As shown, this embodiment provides a method for calculating the fire resistance limit of a mortise and tenon joint timber frame, including:

[0043] S1. Based on the information of the dense thermal conductivity, porosity, and expansion ratio of the intumescent fire-retardant coating at different temperatures, calculate the effective thermal conductivity λ of the fire-retardant coating. s ;

[0044] Fire-retardant coating thermal conductivity λ s The calculation expression is:

[0045]

[0046] In the formula: λ s and λ g ε represents the actual thermal conductivity of the fire-retardant coating in a dense, non-porous state and air, respectively; ε is the porosity of the fire-retardant coating; and m is the expansion ratio of the fire-retardant coating.

[0047] S2. Considering the fire-retardant coating layer and the cross-section of the wooden component as a multi-layer composite material, based on the effective thermal conductivity λ of the fire-retardant coating... s Based on the assumption of uniform pore distribution inside the expanded fire-retardant coating, the composite thermal conductivity λ of the cross section is calculated using Fourier's law of thermal conductivity and the principle of thermal resistance series connection. c And the reduction factor η of the cross section relative to the thermal conductivity of wood.

[0048] Specifically, the composite thermal conductivity λ of the cross section is calculated using Fourier's law of thermal conduction and the principle of thermal resistance series connection. c The calculation expression is:

[0049]

[0050] In the formula: B and H are the width and height of the wooden beam cross-section, respectively; b is the initial dry film thickness of the fire retardant coating, which can be obtained by dividing the mass increment of the fire retardant coating after it has dried on the substrate by the dry film density of the fire retardant coating; λ w λ is the thermal conductivity of wood. e The effective thermal conductivity of the fire-retardant coating.

[0051] Specifically, the reduction factor η of the cross section relative to the thermal conductivity of wood is calculated as follows:

[0052]

[0053] In the formula: λ w The thermal conductivity of the material.

[0054] The reduction factor η based on the thermal conductivity of wood in the width and height directions of the cross section. B and η H The equivalent cross-sectional dimensions are calculated, where the width of the equivalent cross-section is B / η. B The height of the equivalent cross section is H / η H B and H are the width and height of the wooden beam cross-section, respectively.

[0055] S3. The reduction factor η is obtained by weighting the temperature time history curve before the failure temperature of the fire retardant coating, and obtaining the reduction factor η of the wood thermal conductivity in the width and height directions of the cross section. B and η H ;

[0056] S4. The cross-section of the fire-retardant wooden component is equivalent to the cross-section of the un-fire-retardant wooden component, which is larger in size. The equivalent cross-section size is calculated based on the reduction factor of the thermal conductivity of wood in the width and height directions.

[0057] S5. Substitute the equivalent cross-sectional dimensions into the fire resistance limit calculation expression for the mortise and tenon joint timber frame without considering fire retardant coating, and calculate the fire resistance limit of the mortise and tenon joint timber frame after applying intumescent fire retardant coating.

[0058] In this embodiment, the fire resistance limit calculation formula for the mortise and tenon joint wooden frame without considering fire-retardant coating is as follows:

[0059]

[0060] t m =min(T) b ,T j (6)

[0061] In the formula: R is the load-bearing ratio; B and H are the width and height of the timber beam section, respectively; η B η H β and β0 represent the reduction factors of the thermal conductivity of wood in the width and height directions, respectively; β0 is the carbonization rate of wood without fire retardant coating, determined according to relevant standards or tests; T b T j The fire resistance ratings of the beam and the joint, respectively; t m This refers to the fire resistance limit of the timber frame.

[0062] In this embodiment, a commercially available transparent intumescent fire-retardant coating for wood structures was selected (its recommended dosage is 500g / m²). 2Apply evenly to such areas. Figure 4 The mortise and tenon joint on the outer surface of the wooden frame shown is subjected to the following conditions: ISO 834 standard heating, three sides of the beam exposed to fire, four sides of the column exposed to fire, and three-point loading on the top of the beam with a load-bearing ratio of 0.3. The fire-retardant coating dosage is 500g / m². 2 and 1000g / m 2 The fire resistance test values ​​for the timber frame were 64.2 min (joint failure) and 70.1 min (joint failure), respectively. The test determined the required dosage of the fire-retardant coating to be 500 g / m². 2 The initial thickness b of the dry film is 0.2 mm, and the dosage is 1000 g / m³. 2 When b is 0.4 mm.

[0063] The thermal conductivity of the fire-retardant coating is shown in Table 1, and the linear fitting model is as follows: Figure 5 As shown.

[0064] Table 1. Test results of thermal conductivity of fire-retardant coatings as a function of temperature.

[0065]

[0066] The measured values ​​of the expansion ratio and porosity of the fire-retardant coating are shown in Tables 2 and 3.

[0067] Table 2. Test results of expansion ratio and porosity of fire-retardant coatings as a function of temperature (dosage 500 g / m³) 2 )

[0068]

[0069]

[0070] Table 3. Test results of expansion ratio and porosity of fire-retardant coatings as a function of temperature (dosage 1000 g / m³) 2 )

[0071]

[0072] according to Figure 6 The performance parameters of the fireproof coatings in Tables 2 and 3 are shown in Table 4. The effective thermal conductivity of the fireproof coatings is calculated by formula (1).

[0073] Table 4 Effective thermal conductivity of fire-retardant coatings

[0074]

[0075] Taking into account the boundary temperatures of different performance stages of fire-retardant coatings and the boundary temperatures of the thermal conductivity of wood in EC 5, namely 20℃, 180℃, 200℃, 300℃, 350℃, 500℃ and 600℃, the data not listed in Table 3 are obtained by linear interpolation. When the porosity is less than 1, the thermal conductivity of the wood at this time is taken. The corresponding composite thermal conductivity λ is calculated piecewise by Equation (2). c See Table 5.

[0076] Table 5 Composite Thermal Conductivity

[0077]

[0078] Based on the thermal conductivity coefficients of wood specified in Table 5 and EC 5, the corresponding reduction coefficients of thermal conductivity of wood are calculated in segments using Equation (3), as shown in Table 6.

[0079] Table 6. Values ​​of thermal conductivity reduction coefficients for wood at different temperatures.

[0080]

[0081] According to the ISO 834 heating curve, η is weighted and averaged according to the temperature time history curve before the failure temperature of the fire-retardant coating (600℃, corresponding to a heating time of 5.87 min), as shown in equation (7) and Figure 6 As shown:

[0082]

[0083] In the formula, t0~t6 are the ISO834 standard heating times corresponding to 20℃, 180℃, 200℃, 300℃, 350℃, 500℃ and 600℃, respectively, i.e. 0 min, 0.24 min, 0.29 min, 0.69 min, 1.01 min, 2.95 min and 5.87 min; η0~η6 are the reduction coefficients of wood thermal conductivity corresponding to 20℃, 180℃, 200℃, 300℃, 350℃, 500℃ and 600℃, respectively, as shown in Table 5.

[0084] The fire-retardant coating dosage is calculated to be 500 g / m² using equation (7). 2 When the beam width direction η B =0.92, η in the beam height direction H =0.97; Fire retardant coating dosage 1000g / m² 2 η B =0.82, η H =0.92.

[0085] Finally, the dosage of the fire-retardant coating is calculated to be 500 g / m² according to formulas (4) to (6). 2 and 1000g / m 2The fire resistance limit of the timber frame was calculated with B = 185 mm, H = 230 mm, and R = 0.3. The calculated fire resistance limits were 65.3 min (beam failure, the fire resistance limit of the timber beam differs from that of the joint by only 0.4 min) and 69.3 min (joint failure). The errors with the experimental values ​​were (1.7%) and -1.1%, respectively, which showed high accuracy and good agreement with the prediction of failure mode.

[0086] This embodiment applies the 450-500 g / m² coating designed in the experiment by Xu Qingfeng (Xu Qingfeng, Zhang Jin, Shang Jingxiang, et al. Study on fire resistance limit of three-sided fire-exposed wooden beams [J]. Building Structure, 2012, 42(12):127-130). 2 Fire resistance limit tests were conducted on wooden beam specimens (B150 PC50) with fire-retardant coating. The beam width B = 150 mm, beam height H = 300 mm, load ratio R = 0.5, three-point loading, and three-sided exposure to fire. The temperature was increased according to ISO 834 standard, and the fire resistance limit test value was 48.0 min.

[0087] The fire resistance limit of the wooden beam is calculated using equation (4). Since the performance parameters of the fire-retardant coating used in the experiment are lacking, the performance parameters of the fire-retardant coating in Example 1 are used instead. The composite thermal conductivity λ is calculated using equation (2). c See Table 7.

[0088] Table 7 Composite Thermal Conductivity

[0089]

[0090] The corresponding reduction factor η of the thermal conductivity of wood is calculated piecewise using equation (3), as shown in Table 8.

[0091] Table 8. Values ​​of thermal conductivity reduction coefficient for wood at different temperatures.

[0092]

[0093] The reduction factor for the thermal conductivity of wood, calculated from equation (7), is η in the beam width direction. B =0.72, η in the beam height direction H =0.89, and finally the calculated value of the fire resistance limit of the wooden beam specimen is 45.8 min, which is -4.6% of the experimental value.

[0094] The electronic device of this invention includes a central processing unit (CPU), which can perform various appropriate actions and processes according to computer program instructions stored in read-only memory (ROM) or loaded from a storage unit into random access memory (RAM). The RAM may also store various programs and data required for device operation. The CPU, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0095] Multiple components in the device are connected to the I / O interface, including: input units such as keyboards and mice; output units such as various types of displays and speakers; storage units such as disks and optical discs; and communication units such as network interface cards (NICs), modems, and wireless transceivers. The communication unit allows the device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0096] The processing unit executes the various methods and processes described above, such as methods S1 to S5. For example, in some embodiments, methods S1 to S5 may be implemented as computer software programs tangibly contained in a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program may be loaded and / or installed on the device via ROM and / or a communication unit. When the computer program is loaded into RAM and executed by the CPU, one or more steps of methods S1 to S5 described above may be performed. Alternatively, in other embodiments, the CPU may be configured to execute methods S1 to S5 by any other suitable means (e.g., by means of firmware).

[0097] The functions described above in this document can be performed at least in part by one or more hardware logic components. For example, exemplary types of hardware logic components that can be used, without limitation, include: field programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload programmable logic devices (CPLDs), and so on.

[0098] The program code used to implement the methods of the present invention can be written in any combination of one or more programming languages. This program code can be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0099] In the context of this invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0100] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for calculating the fire resistance limit of a mortise and tenon joint timber frame, characterized in that, include: Based on the information on the dense thermal conductivity, porosity, and expansion ratio of intumescent fire-retardant coatings at different temperatures, the effective thermal conductivity λ of the fire-retardant coatings was calculated. s ; Treating the fire-retardant coating layer and the cross-section of the wooden component as a multi-layer composite material, based on the effective thermal conductivity λ of the fire-retardant coating... s The composite thermal conductivity λ of the cross section is calculated using Fourier's law of thermal conduction and the principle of series thermal resistance. c And the reduction factor η of the cross section relative to the thermal conductivity of wood; The reduction factor η is obtained by weighting the temperature time history curves before the failure temperature of the fire-retardant coating, thus obtaining the reduction factors η of the wood thermal conductivity in the width and height directions of the cross section. B and η H ; The cross-section of a fire-retardant wooden component is equivalent to a larger cross-section of an un-fire-retardant wooden component. The equivalent cross-sectional dimensions are calculated based on the reduction factor of the thermal conductivity of wood in the width and height directions. By substituting the equivalent cross-sectional dimensions into the fire resistance limit calculation expression for mortise and tenon joint timber frames without considering fire retardant coating, the fire resistance limit of mortise and tenon joint timber frames after applying intumescent fire retardant coating is calculated.

2. The method for calculating the fire resistance limit of a mortise and tenon joint timber frame according to claim 1, characterized in that, Based on the information of the dense thermal conductivity, porosity and expansion ratio of intumescent fire retardant coatings at different temperatures, and assuming that the internal pores of the expanded fire retardant coating are uniformly distributed, the effective thermal conductivity of the fire retardant coating is calculated.

3. The method for calculating the fire resistance limit of a mortise and tenon joint timber frame according to claim 2, characterized in that, The thermal conductivity of the fire-retardant coating is λ. s The calculation expression is: In the formula: λ s and λ g ε represents the actual thermal conductivity of the fire-retardant coating in a dense, non-porous state and air, respectively; ε is the porosity of the fire-retardant coating; and m is the expansion ratio of the fire-retardant coating.

4. The method for calculating the fire resistance limit of a mortise and tenon joint timber frame according to claim 1, characterized in that, The composite thermal conductivity λ of the cross section is calculated using Fourier's law of thermal conductivity and the principle of thermal resistance series connection. c The calculation expression is: In the formula: B and H are the width and height of the wooden beam cross-section, respectively; b is the initial dry film thickness of the fire-retardant coating; λ w λ is the thermal conductivity of wood. e The effective thermal conductivity of the fire-retardant coating.

5. The method for calculating the fire resistance limit of a mortise and tenon joint timber frame according to claim 4, characterized in that, The initial thickness b of the fire-retardant coating dry film is the mass increment of the fire-retardant coating after it has dried completely on the substrate, divided by the density of the fire-retardant coating dry film.

6. The method for calculating the fire resistance limit of a mortise and tenon joint timber frame according to claim 1, characterized in that, The reduction factor η of the cross section relative to the thermal conductivity of wood is calculated as follows: In the formula: λ w Thermal conductivity of the material.

7. The method for calculating the fire resistance limit of a mortise and tenon joint timber frame according to claim 1, characterized in that, The reduction factor η based on the thermal conductivity of wood in the width and height directions of the cross section. B and η H The equivalent cross-sectional dimensions are calculated, where the width of the equivalent cross-section is B / η. B The height of the equivalent cross section is H / η H B and H are the width and height of the wooden beam cross-section, respectively.

8. The method for calculating the fire resistance limit of a mortise and tenon joint timber frame according to claim 1, characterized in that, The formula for calculating the fire resistance limit of the mortise and tenon joint timber frame without considering fire-retardant coating is as follows: t m =min(T b ,T j ) (6) In the formula: R is the load-bearing ratio; B and H are the width and height of the wooden beam section, respectively; η B η H These are the reduction factors for the thermal conductivity of wood in the width and height directions, respectively. β0 is the carbonization rate of wood without fire retardant coating; T b T j The fire resistance ratings of the beam and the joint, respectively; t m This refers to the fire resistance limit of the timber frame.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the program, it implements the method as described in any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method as described in any one of claims 1 to 8.

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