A seismic design method of a suspended ceiling system

Abstract

The application provides an anti-seismic design method of a suspended ceiling system, and relates to the field of anti-seismic performance research, and comprises the following steps: S1, determining the size of the suspended ceiling; S2, determining the type, component specification and structure form of the suspended ceiling product, and determining the size and unit mass of the suspender, the panel, the main furring, the secondary furring and the cross furring component; S3, checking the vertical bearing capacity and slenderness ratio of the suspender; S4, calculating the earthquake action borne by the suspended ceiling under frequent earthquakes; S5, calculating the lateral stiffness of the suspender according to the stress characteristics; S6, calculating the displacement of the suspended ceiling under horizontal earthquake action; S7, determining the PFA of the floor where the suspended ceiling is located; S8, determining the upper and lower limits of the gap width; and S9, obtaining the gap width for avoiding the damage of the furring node according to the floor PFA and the furring internal force calculation formula. w In combination with the upper and lower limits of the gap width, a value is set for allowing the collision of the suspended ceiling but avoiding the damage of the suspended ceiling. w The application adopts the above method to complete the suspended ceiling system meeting the anti-seismic bearing capacity requirement.

Description

Technical Field

[0001] This invention relates to the field of seismic performance research of non-structural components, and in particular to a seismic design method for a suspended ceiling system. Background Technology

[0002] Past earthquake disaster investigations have shown that while the main structure may suffer relatively minor damage after an earthquake, non-structural components of buildings often suffer severe damage, indicating their poor seismic resistance. Damage to non-structural components not only leads to significant economic losses and disruption of building functionality but also impacts the restoration of building functions after an earthquake. Ceilings, as a widely used type of non-structural component in buildings, are prone to severe damage under seismic loads, with typical damage characteristics including joint failure, panel detachment, and even complete collapse. Therefore, improving the seismic performance of ceiling systems is crucial for mitigating earthquake damage and maintaining the normal functionality of buildings. Reasonable seismic design of ceiling systems is an important method to achieve this goal.

[0003] Currently, most domestic and international seismic codes specify seismic structural measures for suspended ceilings, but lack quantitative seismic design methods. my country's seismic codes stipulate the use of the equivalent lateral force method to calculate the magnitude of seismic forces borne by the suspended ceiling, but how to guide the seismic design of the ceiling based on this seismic force is unclear. Furthermore, the equivalent lateral force method does not consider the interaction between non-structural components and the surrounding structure. However, boundary conditions significantly affect the seismic performance of suspended ceilings. Damage to suspended ceilings under seismic loads often begins at their ends, such as the keel ends detaching from the edge keels, keel joint failure caused by violent end collisions, or excessive accumulation of internal forces at the boundary with seismic clamps leading to keel joint failure. Therefore, the commonly used equivalent lateral force method is not directly applicable to the seismic design of suspended ceiling systems.

[0004] There is an urgent need to provide a seismic design method for ceiling systems to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a seismic design method for a ceiling system. By verifying the vertical bearing capacity of the hangers, the displacement of the ceiling system under horizontal seismic action, and the bearing capacity of the keel nodes, a ceiling system that meets the seismic bearing capacity requirements can be determined.

[0006] To achieve the above objectives, the present invention provides a seismic design method for a suspended ceiling system, comprising the following steps: S1: Determine the ceiling dimensions. Based on the floor plan dimensions of the room where the ceiling is located, determine the length of the ceiling. L ceil and width W ceilThe length of the hanger is determined based on the room's clearance requirements, the impact of changes in hanger length on the ceiling's seismic performance, and the height of HVAC and other equipment installed with the ceiling. The length of the hanger is equal to the ceiling height. S2: Calculate the ceiling mass, determine the type, component specifications, and structural form of the ceiling products, and determine the dimensions and unit mass of the hangers, panels, main joists, secondary joists, and cross braces. Combined with the ceiling dimensions obtained in S1, calculate the number of hangers. N tr The formula is as follows: ; The total mass of the ceiling model is calculated based on the mass and quantity of each individual component. M ; S3: Verify the vertical bearing capacity of the hanger, based on the cross-sectional area of ​​the hanger. A and the yield strength of the material F y The formula for verifying the vertical bearing capacity of the hanger is as follows: ; If the verification formula holds true, it means the vertical bearing capacity of the hanger meets the requirements; if the verification formula does not hold true, adjust the diameter of the hanger. d Continue until the vertical bearing capacity meets the verification formula; Based on the length of the boom L ,diameter d And determined based on its two-end constraints The slenderness ratio of the boom under tension and compression The calculation is performed using the following formula: ; S4: Calculate the seismic load on the suspended ceiling under frequent earthquakes; S5: Calculate the lateral stiffness of the suspension rod based on the force characteristics; S6: Calculate the displacement of the suspended ceiling under horizontal seismic action; S7: Determine the PFA of the floor where the suspended ceiling is located; S8: Determine the upper and lower limits of the gap width; S9: Based on the floor PFA and keel internal force calculation formulas obtained in S7, the gap width to avoid keel joint failure is obtained. w Based on the upper and lower limits of the gap width determined in S8, a limit is set that allows for collisions with the ceiling while preventing damage to the ceiling. w The value indicates the end of the ceiling system design.

[0007] Preferably, in step S4, the seismic load borne by the suspended ceiling under frequent earthquakes is calculated using the calculation formula of the equivalent force measurement method. : ; In the formula: This is the functional coefficient for non-structural components, with a value set to 1.0; This is the category coefficient for non-structural components, with a value set to 0.9; This is the state coefficient, with a value set to 2.0; This is the location coefficient, set to 2.0 based on the building's vertex values. This is the maximum value of the seismic influence coefficient, determined based on the seismic fortification information of the building where the ceiling is located; G This refers to the weight of the suspended ceiling.

[0008] Preferably, the lateral stiffness of a single rod in S5 k The calculation is based on the stress characteristics and is related to the connection method at the upper and lower ends. For the hangers in a single-layer suspended ceiling, the upper end is anchored in the structural floor slab, and the lower end is fixed to the keel component using hangers or screws. Under the above boundary conditions, the upper end of the hanger is considered a fixed support, and the lower end is considered a sliding support. The lateral stiffness of a single hanger... k Calculate using the following formula: ; In the formula: E The elastic modulus of steel; I Let be the moment of inertia of the section of the boom; L This is the length of the boom.

[0009] Preferably, in S7, the acceleration amplification factor for the bottom layer of the structure is 1.0, the acceleration amplification factor for the top layer of the structure is 2.0, the intermediate floors are linearly interpolated according to height, and the PFA of the floor where the ceiling is located is calculated according to the following formula: ; In the formula: z This refers to the height of the ceiling installation location; h The height is the height of the main structure; PGA is the peak ground acceleration in the area where the ceiling is located.

[0010] Preferably, when determining the size of the gap width at the keel end in S8, it is necessary to simultaneously prevent the keel end from falling off the side keel or the keel node from being damaged by collision. To prevent the keel end from detaching from the side keel, the flange width of the side keel should be considered. d w and safety factor a Limit d lim The calculation formula is: ; Minimum width of the gap at the top of the suspension head wmin for: ; In the formula: L The length of the boom. The inter-story drift angle limit of the main structure under frequent earthquakes; End gap w The width range is: .

[0011] Preferably, in S9, the displacement of the suspended ceiling under horizontal seismic action is... D With the upper limit of the gap width d lim Compare the systems to determine whether the ceiling system will exhibit collision behavior at the boundaries; Ceiling displacement under horizontal seismic load D Calculate according to the following formula: ; In the formula: For the horizontal seismic forces borne by the suspended ceiling; k The lateral stiffness of a single hanger rod; n This refers to the total number of hangers; like This indicates that the end of the keel will not collide with the side keel; in this case, the gap width value is set to [value missing]. d lim ; If the ceiling displaces under horizontal seismic action D > d lim This means the ceiling may collide with surrounding components, requiring an appropriate gap width to be designed. w To prevent damage to the keel joints, the specific process is as follows: The bearing capacity of the keel nodes was obtained in advance through extensive numerical calculations. F P The relationship between the keel and PFA was fitted to obtain the load-bearing capacity of the ceiling joists under different areas and gap widths. F The formula for calculating PFA: ; In the formula: and These are the fitting coefficients; F P The load-bearing capacity of the keel joints was determined through test results. Based on the floor PFA calculated in S7 and the formula for calculating the internal force of the keel, the gap width to avoid failure of the keel joint is obtained. w Based on the upper and lower limits of the gap width determined in S8, a limit is set that allows for collisions with the ceiling while preventing damage to the ceiling.w value.

[0012] Preferably, if a suitable gap width value cannot be found so that the load-bearing capacity of the keel node meets the requirements, the ceiling boundary condition is designed as a two-sided fixed and two-sided semi-free type, and the load-bearing capacity of the keel node near the fixed end is verified.

[0013] Preferably, the verification process is as follows: A large number of numerical calculations are performed beforehand to obtain the relationship between the load-bearing capacity of the keel nodes and the PFA (Pressure Aspect Ratio) of the suspended ceiling with fixed sides and semi-free sides. The load-bearing capacity of the keel is then fitted to obtain the load-bearing capacity of the suspended ceiling under different areas. F Based on the calculation formula of PFA, the floor PFA and the keel internal force calculation formula obtained in S7 are used to verify whether the keel node has been damaged. If the load-bearing capacity of the keel node meets the requirements, the ceiling system design is completed. If the load-bearing capacity of the keel nodes does not meet the requirements, special settings should be made to add seismic or damping supports to the ceiling system.

[0014] Therefore, the present invention adopts the above-mentioned seismic design method for a suspended ceiling system, and the technical effects are as follows: (1) By simplifying the ceiling system into a single-degree-of-freedom system and combining the calculation results of the equivalent lateral force method, this invention can determine whether the ceiling system will have collision behavior at the boundary.

[0015] (2) Based on the calculation formula of the keel bearing capacity and the peak floor acceleration obtained by prefitting, the present invention can determine whether the keel node will be damaged under different types of boundary conditions.

[0016] (3) The present invention can verify the bearing capacity of ceiling keel nodes with different areas and can design the boundary conditions of the ceiling. Attached Figure Description

[0017] Figure 1 This is a flowchart of a seismic design method for a ceiling system according to the present invention; Figure 2 This is a flowchart illustrating the calculation of the vertical bearing capacity of the suspension rod in an embodiment of the present invention. Figure 3 This is a flowchart of the collision calculation for the top of the suspended ceiling in an embodiment of the present invention; Figure 4 This is a schematic diagram of the calculation of a single-degree-of-freedom ceiling system in an embodiment of the present invention; Figure 5 This is a diagram showing the relationship between axial force and PFA at the keel node in an embodiment of the present invention. Figure 6 This is a flowchart illustrating the calculation of the bearing capacity of the keel node under end constraint in an embodiment of the present invention. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0020] Example like Figure 1 As shown, the present invention provides a seismic design method for a suspended ceiling system, comprising the following steps: S1: As Figure 2 The dimensions of the suspended ceiling are determined as shown. Based on the floor plan dimensions of the room where the suspended ceiling is located, the length of the suspended ceiling is determined. L ceil and width W ceil The length of the hanger is determined based on the room's clearance requirements, the impact of changes in hanger length on the ceiling's seismic performance, and the height of HVAC and other equipment installed with the ceiling. The length of the hanger is equal to the ceiling height. S2: Calculate the ceiling mass, determine the type, component specifications, and structural form of the ceiling products, and determine the dimensions and unit mass of the hangers, panels, main joists, secondary joists, and cross braces. Combined with the ceiling dimensions obtained in S1, calculate the number of hangers. N tr The formula is as follows: ; The total mass of the ceiling model is calculated based on the mass and quantity of each individual component. M ; S3: Verify the vertical load-bearing capacity of the hanger rods. Based on the material strength, diameter, and quantity of the hanger rods, calculate the maximum vertical load-bearing capacity that the hanger rods can withstand, and compare it with the total weight G of the suspended ceiling to determine whether the vertical load-bearing capacity of the hanger rods meets the requirements. If it does not meet the requirements, increase the diameter of the hanger rods until it does. Furthermore, considering the connection method at the upper and lower ends of the hanger rods, verify the load-bearing capacity of the anchors at the upper end of the hanger rods and the load-bearing capacity of the connectors at the lower end of the hanger rods.

[0021] Based on the cross-sectional area of ​​the boom A and the yield strength of the material F y The formula for verifying the vertical bearing capacity of the hanger is as follows: ; If the verification formula is true, it means that the vertical bearing capacity of the hanger meets the requirements; if the verification formula is false, adjust the diameter of the hanger until the vertical bearing capacity meets the verification formula. Further based on the length of the boom L ,diameter d And determined based on its two-end constraints The slenderness ratio of the boom under tension and compression The calculation is performed using the following formula: ; In the collision calculation of the ceiling of a four-sided free-form suspended ceiling, S4: calculate the seismic force borne by the suspended ceiling under frequent earthquakes; such as Figure 3 As shown in Figure S4, the seismic load on the suspended ceiling under frequent earthquakes is calculated using the formula of the equivalent force measurement method. : ; In the formula: This is the functional coefficient for non-structural components, with a value set to 1.0; This is the category coefficient for non-structural components, with a value set to 0.9; This is the state coefficient, with a value set to 2.0; This is the location coefficient, set to 2.0 based on the building's vertex values. This is the maximum value of the seismic influence coefficient, determined based on the seismic fortification information of the building where the ceiling is located; G This refers to the weight of the suspended ceiling.

[0022] S5: Calculate the lateral stiffness of the suspension rod based on the force characteristics; lateral stiffness of a single suspension rod in S5. k The calculation is based on the stress characteristics and is related to the connection method at the upper and lower ends. For the hangers in a single-layer suspended ceiling, the upper end is anchored in the structural floor slab, and the lower end is fixed to the keel component using hangers or screws. Under the above boundary conditions, the upper end of the hanger is considered a fixed support, and the lower end is considered a sliding support. The lateral stiffness of a single hanger... k Calculate using the following formula: ; In the formula: E The elastic modulus of steel; I Let be the moment of inertia of the section of the boom; L This is the length of the boom.

[0023] S6: Calculate the displacement of the suspended ceiling under horizontal seismic action; such as Figure 4 As shown, the ceiling system is simplified to a single-degree-of-freedom model, and the frictional behavior between the ends of the keel and the edge keel is not considered. The displacement of the ceiling under horizontal seismic action is... D Calculate according to the following formula: ; In the formula: For the horizontal seismic forces borne by the suspended ceiling; k The lateral stiffness of a single hanger rod; n This refers to the total number of hangers; S7: Determine the Peak Floor Acceleration (PFA) of the floor where the ceiling is located; based on the floor location of the ceiling installation, determine the peak floor acceleration (PFA). Currently, there are three main methods for determining PFA: the first method is to calculate it based on the floor acceleration amplification factor specified in the code combined with the peak ground acceleration; the second method is to calculate it using empirical formulas proposed in existing literature; and the third method is to directly perform seismic time history analysis on the building structure. The calculation method for PFA should be determined according to the actual calculation requirements.

[0024] In this embodiment, the third method is used for calculation. In S7, the acceleration amplification factor of the bottom layer of the structure is 1.0, the acceleration amplification factor of the top layer of the structure is 2.0, the intermediate floors are linearly interpolated according to height, and the PFA of the floor where the ceiling is located is calculated according to the following formula: ; In the formula: z This refers to the height of the ceiling installation location; h The height is the height of the main structure; PGA is the peak ground acceleration in the area where the ceiling is located.

[0025] S8: Determine the upper and lower limits of the gap width; When determining the size of the gap width at the keel end in S8, it is necessary to simultaneously prevent the keel end from falling off the side keel or the keel node from being damaged by collision. To prevent the keel end from detaching from the side keel, the flange width of the side keel should be considered. d w and safety factor a Limit d lim The calculation formula is: ; Minimum width of the gap at the top of the suspension head w min for: ; In the formula: L The length of the boom. The inter-story drift angle limit of the main structure under frequent earthquakes; End gap w The width range is: .

[0026] S9: Based on the floor PFA and keel internal force calculation formulas obtained in S7, the gap width to avoid keel joint failure is obtained. w Based on the upper and lower limits of the gap width determined in S8, a limit is set that allows for collisions with the ceiling while preventing damage to the ceiling. w The value indicates the end of the ceiling system design.

[0027] S9 will measure the displacement of the suspended ceiling under horizontal seismic action. D With the upper limit of the gap width d lim Compare the systems to determine whether the ceiling system will exhibit collision behavior at the boundaries; like This indicates that the end of the keel will not collide with the side keel; in this case, the gap width value is set to [value missing]. d lim ; If the ceiling displaces under horizontal seismic action D > d lim This means the ceiling may collide with surrounding components, requiring an appropriate gap width to be designed. w To prevent damage to the keel joints, for four-sided free-form suspended ceilings, since the keel joints near the boundaries experience the greatest stress, only these joints need to be calculated. Considering that the keel joints primarily bear axial forces under seismic loading, only the axial bearing capacity of the keel joints is checked. Figure 6 As shown, the specific process is as follows: The bearing capacity of the keel nodes was obtained in advance through extensive numerical calculations. F P The relationship diagram with PFA, such as Figure 5 As shown, the load-bearing capacity of the keel under different ceiling areas and different gap widths was obtained by fitting. F The formula for calculating PFA: ; In the formula: and These are the fitting coefficients; F P The load-bearing capacity of the keel joints was determined through test results. Based on the floor PFA calculated in S7 and the formula for calculating the internal force of the keel, the gap width to avoid failure of the keel joint is obtained. w Based on the upper and lower limits of the gap width determined in S8, a limit is set that allows for collisions with the ceiling while preventing damage to the ceiling. w value.

[0028] If a suitable gap width value cannot be found so that the load-bearing capacity of the keel node meets the requirements, the ceiling boundary conditions are designed as two fixed sides and two semi-free sides, and the load-bearing capacity of the keel node near the fixed end is verified.

[0029] The verification process is as follows: Beforehand, a large number of numerical calculations were performed to obtain the relationship between the load-bearing capacity of the keel nodes and the PFA (Pressure Aspect Ratio) of the suspended ceiling with two fixed sides and two semi-free sides. The keel load-bearing capacity under different ceiling areas was then obtained by fitting the data. FBased on the calculation formula of PFA, the floor PFA and the keel internal force calculation formula obtained in S7 are used to verify whether the keel node has been damaged. If the load-bearing capacity of the keel node meets the requirements, the ceiling system design is completed. If the load-bearing capacity of the keel nodes does not meet the requirements, special settings should be made to add seismic or damping supports to the ceiling system.

[0030] Therefore, the present invention adopts the above-mentioned seismic design method for a ceiling system, which includes three parts: vertical bearing capacity verification of the hanger rod, collision verification of the top of the four-sided free-type ceiling, and bearing capacity verification of the ceiling keel node with two fixed sides and two semi-free sides, to obtain a ceiling system that meets the seismic bearing capacity requirements.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A seismic design method for a suspended ceiling system, characterized in that, Includes the following steps: S1: Determine the ceiling dimensions. Based on the floor plan dimensions of the room where the ceiling is located, determine the length of the ceiling. L ceil and width W ceil The length of the hanger is determined based on the room's clearance requirements, the impact of changes in hanger length on the ceiling's seismic performance, and the height of the HVAC equipment installed with the ceiling. The length of the hanger is equal to the ceiling height. S2: Calculate the ceiling mass, determine the type, component specifications, and structural form of the ceiling products, and determine the dimensions and unit mass of the hangers, panels, main joists, secondary joists, and cross braces. Combined with the ceiling dimensions obtained in S1, calculate the number of hangers. N tr The formula is as follows: ； The total mass of the ceiling model is calculated based on the mass and quantity of each individual component. M ; S3: Verify the vertical bearing capacity and slenderness ratio of the hanger, based on the cross-sectional area of ​​the hanger. A and the yield strength of the material F y The formula for verifying the vertical bearing capacity of the hanger is as follows: ； If the verification formula holds true, it means the vertical bearing capacity of the hanger meets the requirements; if the verification formula does not hold true, adjust the diameter of the hanger. d Continue until the vertical bearing capacity meets the verification formula; Based on the length of the boom L ,diameter d And determined based on its two-end constraints The slenderness ratio of the boom under tension and compression The calculation is performed using the following formula: ； S4: Calculate the seismic load on the suspended ceiling under frequent earthquakes; S5: Calculate the lateral stiffness of the suspension rod based on the force characteristics; S6: Calculate the displacement of the suspended ceiling under horizontal seismic action; S7: Determine the PFA of the floor where the suspended ceiling is located; S8: Determine the upper and lower limits of the gap width; S9: Calculation formulas for floor PFA and keel internal forces obtained from S7: ; Obtain the gap width to avoid damage to the keel joints. w In the formula, For the load-bearing capacity of the keel, and These are the fitting coefficients; F P The load-bearing capacity of the keel joints was determined through test results; combined with the upper and lower limits of the gap width defined in S8, a limit was set that allows for collisions with the ceiling while preventing damage to the ceiling. w The value indicates the end of the ceiling system design.

2. The seismic design method for a suspended ceiling system according to claim 1, characterized in that, Based on the calculation formula of the equivalent force measurement method, the seismic force borne by the suspended ceiling under frequent earthquakes is calculated in S4. : ； In the formula: This is the functional coefficient for non-structural components, with a value set to 1.0; This is the category coefficient for non-structural components, with a value set to 0.9; This is the state coefficient, with a value set to 2.0; This is the location coefficient, set to 2.0 based on the building's vertex values. This is the maximum value of the seismic influence coefficient, determined based on the seismic fortification information of the building where the ceiling is located; G This refers to the weight of the suspended ceiling.

3. The seismic design method for a suspended ceiling system according to claim 1, characterized in that, Lateral stiffness of a single rod in S5 k The calculation is based on the stress characteristics and is related to the connection method at the upper and lower ends. For the hangers in a single-layer suspended ceiling, the upper end is anchored in the structural floor slab, and the lower end is fixed to the keel component using hangers or screws. Under the above boundary conditions, the upper end of the hanger is considered a fixed support, and the lower end is considered a sliding support. The lateral stiffness of a single hanger... k Calculate using the following formula: ； In the formula: E The elastic modulus of steel; I Let be the moment of inertia of the section of the boom; L This is the length of the boom.

4. The seismic design method for a suspended ceiling system according to claim 1, characterized in that, In S7, the acceleration amplification factor for the bottom layer of the structure is 1.0, and the acceleration amplification factor for the top layer is 2.

0. For intermediate floors, linear interpolation is performed based on height. The PFA of the floor containing the suspended ceiling is calculated using the following formula: ； In the formula: z This refers to the height of the ceiling installation location; h The height is the height of the main structure; PGA is the peak ground acceleration in the area where the ceiling is located.

5. The seismic design method for a suspended ceiling system according to claim 4, characterized in that, When determining the width of the gap at the end of the keel in S8, it is necessary to simultaneously prevent the end of the keel from falling off the side keel or the keel node from being damaged by a collision. To prevent the keel end from detaching from the side keel, the flange width of the side keel should be considered. d w and safety factor a Limit d lim The calculation formula is: ； Minimum width of the gap at the top of the suspension head w min for: ； In the formula: L The length of the boom. The inter-story drift angle limit of the main structure under frequent earthquakes; End gap w The width range is: .

6. The seismic design method for a suspended ceiling system according to claim 5, characterized in that, S9 will measure the displacement of the suspended ceiling under horizontal seismic action. D With the upper limit of the gap width d lim Compare the systems to determine whether the ceiling system will exhibit collision behavior at the boundaries; Ceiling displacement under horizontal seismic load D Calculate according to the following formula: ； In the formula: For the horizontal seismic forces borne by the suspended ceiling; k The lateral stiffness of a single hanger rod; n This refers to the total number of hangers; like This indicates that the end of the keel will not collide with the side keel; in this case, the gap width value is set to [value missing]. d lim ; If the ceiling displaces under horizontal seismic action D > d lim This means the ceiling may collide with surrounding components, requiring an appropriate gap width to be designed. w To prevent damage to the keel joints, the specific process is as follows: The bearing capacity of the keel nodes was obtained in advance through extensive numerical calculations. F P The relationship between the keel and PFA was fitted to obtain the load-bearing capacity of the ceiling joists under different areas and gap widths. F The formula for calculating PFA.

7. A seismic design method for a suspended ceiling system according to claim 6, characterized in that, If a suitable gap width cannot be found to ensure that the load-bearing capacity of the keel node meets the requirements, the ceiling boundary conditions are designed as two fixed sides and two semi-free sides, and the load-bearing capacity of the keel node near the fixed end is verified.

8. The seismic design method for a suspended ceiling system according to claim 7, characterized in that, The verification process is as follows: Beforehand, a large number of numerical calculations were performed to obtain the relationship between the load-bearing capacity of the keel nodes and the PFA (Pressure Aspect Ratio) of the suspended ceiling with two fixed sides and two semi-free sides. The keel load-bearing capacity under different ceiling areas was then obtained by fitting the data. F Based on the calculation formula of PFA, the floor PFA and the keel internal force calculation formula obtained in S7 are used to verify whether the keel node has been damaged. If the load-bearing capacity of the keel node meets the requirements, the ceiling system design is completed. If the load-bearing capacity of the keel nodes does not meet the requirements, special settings should be made to add seismic or damping supports to the ceiling system.

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