GB/T 51408-2021 Standard for seismic isolation design of building English
Standard for seismic isolation design of building
1 General provisions
1.0.1 This standard is developed to implement the relevant laws and regulations of the nation on earthquake prevention and disaster reduction of architectural engineering, implement the policy of prevention first, and further improve the seismic safety of buildings by adopting seismic isolation technology so that the building function is not interrupted, the casualties and secondary disasters are avoided and the social impact and economic losses are reduced after the fortification-level earthquake.
1.0.2 This standard is applicable to the seismic isolation design of buildings as well as the seismic isolation design for retrofit of existing buildings in areas with a seismic fortification intensity of 6 or above.
1.0.3 Unless otherwise specified, the basic fortification goal of seismically isolated buildings is as follows: when subjected to a fortification-level earthquake with the intensity equivalent to the basic intensity of the area, the main structure is basically without damage or can continue to be used without repair; in case of rare earthquake, the structure may be damaged and can be used again after repair; when a building of special fortification category is subjected to very rare earthquake, it will not collapse or be damaged to the life-threatening extent.
1.0.4 When there are special requirements for the use functions of structural elements, non-structural components and auxiliary equipment of the seismically isolated building, the basic fortification goal as well as those specified in the standards for the seismic performance of the structural elements, non-structural elements and auxiliary equipment shall be met.
1.0.5 When the height, regularity, structure type, seismic isolation interface setting of seismically isolated buildings exceed the relevant standards or the seismic fortification criterion has special requirements, supplementary analysis and demonstration should be conducted according to Annex A of this standard by adopting the structure seismic performance design method.
1.0.6 The design of seismically isolated buildings and the seismic isolation design for retrofit of existing buildings shall meet those specified in both this standard and the current relevant standards of the nation.
2 Terms and symbols
2.1 Terms
2.1.1
seismically isolated building
building with seismic isolation interface in the structure to realize the seismic isolation function so as to reduce the earthquake response, including superstructure, seismic isolation interface, substructure and foundation
2.1.2
seismic isolation interface
general name of all components of a seismically isolated building that are arranged at the foundation, bottom or between substructure and superstructure, including seismic isolator, damping device, anti-wind device, stopper, anti-tension device, auxiliary device and related supporting or connecting elements
2.1.3
superstructure
structure of a seismically isolated building above the seismic isolation interface
2.1.4
substructure
structure of a seismically isolated building below the seismic isolation interface, excluding the foundation
2.1.5
base isolation
seismic isolation system with seismic isolation interface at the bottom of the building
2.1.6
inter-storey isolation
seismic isolation system with seismic isolation interface at an inter-storey position above the bottom of the building
2.1.7
roof isolation
seismic isolation system with seismic isolation interface between the column top or wall top and the top roof of the building
2.1.8
seismic isolator
support of the seismic isolation interface for bearing the superstructure and with the ability of isolation and deformation
2.1.9
damping device
device that attenuates the seismic response of the seismic isolation interface by absorbing and dissipating seismic input energy
2.1.10
anti-wind device
device of the seismic isolation interface for resisting the wind load of the superstructure, which may be an integral part of the seismic isolator or set separately
2.1.11
anti-tension device
device used in seismic isolation interface to resist vertical tension caused by overturning action of superstructure
2.1.12
stopper
device for limiting displacement of seismic isolation interface from exceeding reasonable design range
2.1.13
base shear ratio
ratio of base shear of superstructure after seismic isolation to that before seismic isolation of building structure under the action of fortification-level earthquake
2.1.14
equivalent stiffness
secant stiffness of seismic isolation interface or seismic isolator corresponding to a specific horizontal displacement
2.1.15
equivalent damping ratio
damping ratio of seismic isolation interface or seismic isolator corresponding to a specific horizontal displacement
2.1.16
very rare earthquake
seismic oscillation with an annual exceeding probability of 10-4 within the design reference period
2.2 Symbols
2.2.1 Actions and action effects
D——the permanent load;
E——the limiting safe earthquake action;
Fek——the characteristic value of total horizontal earthquake action of structure;
Fji——the characteristic value of the horizontal earthquake action at Mass Point i in the j-th vibration mode, N
FXji, FYji and Frji——the characteristic values of horizontal earthquake action at Mass Point i in the j-th vibration mode along the directions of x, y and rotation angle, respectively;
FEvk——the characteristic value of total vertical earthquake action of the structure;
Fvi——the characteristic value of vertical earthquake action at the Mass Point i;
Fi——the characteristic value of the horizontal earthquake action at the Mass Point i;
Fh——the horizontal shear force of the seismic isolation interface;
Kh——the horizontal stiffness of seismic isolation interface;
fck——the characteristic value of axial compressive strength of concrete;
fspk——the characteristic value of strength of section steel in embedded columns at the end of shear wall or of steel plates in the wall;
G——the representative value of total gravity load of the superstructure;
Gi and Gj——the representative values of gravity load concentrated on Mass Points i and j representatively;
Geq——the equivalent total gravity load of the superstructure;
L——the upper live load;
∑Mc——the sum of the bending moments combined in the clockwise or counterclockwise direction in the column end section above and below the joints;
Foreword ii
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Basic requirements
3.1 General requirements
3.2 Site, subgrade and foundation
3.3 Test and observation
4 Earthquake action and structure seismic isolation checking
4.1 General requirements
4.2 Design response spectrum and ground motion input
4.3 Calculation of earthquake action
4.4 Element section design
4.5 Checking for superstructure deformation
4.6 Design for seismic isolation interface
4.7 Design for substructure of isolation layer
5 Seismic isolator and isolation details
5.1 General requirements
5.2 Checking for seismic isolator
5.3 Connection of seismic isolator and structure
5.4 Isolation seam
5.5 Fixtures and piping across the seismic isolation interface
5.6 Expansion joint
5.7 Inspection and isolation identification
6 Multi-storey and tall buildings
6.1 General requirements
6.2 Design for seismic isolation interface
6.3 Structural design
7 Large-span roof buildings
7.1 General requirements
7.2 Design for seismic isolation interface
7.3 Structural design for large-span roof buildings
7.4 Supporting structure design
8 Multi-storey masonry buildings and multi-storey masonry building with R. C. frames on ground floors
8.1 General requirements
8.2 Design for seismic isolation interface
8.3 Structural design
9 Nuclear power plant buildings
9.1 General requirements
9.2 Design for seismic isolation
9.3 Floor response spectrum
9.4 Requirements for seismic isolator
9.5 Inspection rules for elastomeric seismic-protection isolators
9.6 Earthquake monitoring and alarm
10 Seismic isolation design for retrofit of existing or historic buildings
10.1 General requirements
10.2 Seismic isolation design for retrofit of existing buildings
10.3 Seismic isolation design for retrofit of historic buildings
11 Rural residential buildings
11.1 General requirements
11.2 Building isolation design essentials
Annex A Seismic performance design of seismically isolated buildings
Annex B Equations for calculating the influence coefficient for complex mode
Annex C Connection design of seismic isolator
Annex D Mechanical analysis model of seismic isolator and basic mechanical performance requirements
Annex E Underpinning methods for strengthening walls and columns of existing buildings
Explanation of wording in this standard
List of quoted standards
GB/T 51408-2021 Standard for seismic isolation design of building English
Standard for seismic isolation design of building
1 General provisions
1.0.1 This standard is developed to implement the relevant laws and regulations of the nation on earthquake prevention and disaster reduction of architectural engineering, implement the policy of prevention first, and further improve the seismic safety of buildings by adopting seismic isolation technology so that the building function is not interrupted, the casualties and secondary disasters are avoided and the social impact and economic losses are reduced after the fortification-level earthquake.
1.0.2 This standard is applicable to the seismic isolation design of buildings as well as the seismic isolation design for retrofit of existing buildings in areas with a seismic fortification intensity of 6 or above.
1.0.3 Unless otherwise specified, the basic fortification goal of seismically isolated buildings is as follows: when subjected to a fortification-level earthquake with the intensity equivalent to the basic intensity of the area, the main structure is basically without damage or can continue to be used without repair; in case of rare earthquake, the structure may be damaged and can be used again after repair; when a building of special fortification category is subjected to very rare earthquake, it will not collapse or be damaged to the life-threatening extent.
1.0.4 When there are special requirements for the use functions of structural elements, non-structural components and auxiliary equipment of the seismically isolated building, the basic fortification goal as well as those specified in the standards for the seismic performance of the structural elements, non-structural elements and auxiliary equipment shall be met.
1.0.5 When the height, regularity, structure type, seismic isolation interface setting of seismically isolated buildings exceed the relevant standards or the seismic fortification criterion has special requirements, supplementary analysis and demonstration should be conducted according to Annex A of this standard by adopting the structure seismic performance design method.
1.0.6 The design of seismically isolated buildings and the seismic isolation design for retrofit of existing buildings shall meet those specified in both this standard and the current relevant standards of the nation.
2 Terms and symbols
2.1 Terms
2.1.1
seismically isolated building
building with seismic isolation interface in the structure to realize the seismic isolation function so as to reduce the earthquake response, including superstructure, seismic isolation interface, substructure and foundation
2.1.2
seismic isolation interface
general name of all components of a seismically isolated building that are arranged at the foundation, bottom or between substructure and superstructure, including seismic isolator, damping device, anti-wind device, stopper, anti-tension device, auxiliary device and related supporting or connecting elements
2.1.3
superstructure
structure of a seismically isolated building above the seismic isolation interface
2.1.4
substructure
structure of a seismically isolated building below the seismic isolation interface, excluding the foundation
2.1.5
base isolation
seismic isolation system with seismic isolation interface at the bottom of the building
2.1.6
inter-storey isolation
seismic isolation system with seismic isolation interface at an inter-storey position above the bottom of the building
2.1.7
roof isolation
seismic isolation system with seismic isolation interface between the column top or wall top and the top roof of the building
2.1.8
seismic isolator
support of the seismic isolation interface for bearing the superstructure and with the ability of isolation and deformation
2.1.9
damping device
device that attenuates the seismic response of the seismic isolation interface by absorbing and dissipating seismic input energy
2.1.10
anti-wind device
device of the seismic isolation interface for resisting the wind load of the superstructure, which may be an integral part of the seismic isolator or set separately
2.1.11
anti-tension device
device used in seismic isolation interface to resist vertical tension caused by overturning action of superstructure
2.1.12
stopper
device for limiting displacement of seismic isolation interface from exceeding reasonable design range
2.1.13
base shear ratio
ratio of base shear of superstructure after seismic isolation to that before seismic isolation of building structure under the action of fortification-level earthquake
2.1.14
equivalent stiffness
secant stiffness of seismic isolation interface or seismic isolator corresponding to a specific horizontal displacement
2.1.15
equivalent damping ratio
damping ratio of seismic isolation interface or seismic isolator corresponding to a specific horizontal displacement
2.1.16
very rare earthquake
seismic oscillation with an annual exceeding probability of 10-4 within the design reference period
2.2 Symbols
2.2.1 Actions and action effects
D——the permanent load;
E——the limiting safe earthquake action;
Fek——the characteristic value of total horizontal earthquake action of structure;
Fji——the characteristic value of the horizontal earthquake action at Mass Point i in the j-th vibration mode, N
FXji, FYji and Frji——the characteristic values of horizontal earthquake action at Mass Point i in the j-th vibration mode along the directions of x, y and rotation angle, respectively;
FEvk——the characteristic value of total vertical earthquake action of the structure;
Fvi——the characteristic value of vertical earthquake action at the Mass Point i;
Fi——the characteristic value of the horizontal earthquake action at the Mass Point i;
Fh——the horizontal shear force of the seismic isolation interface;
Kh——the horizontal stiffness of seismic isolation interface;
fck——the characteristic value of axial compressive strength of concrete;
fspk——the characteristic value of strength of section steel in embedded columns at the end of shear wall or of steel plates in the wall;
G——the representative value of total gravity load of the superstructure;
Gi and Gj——the representative values of gravity load concentrated on Mass Points i and j representatively;
Geq——the equivalent total gravity load of the superstructure;
L——the upper live load;
∑Mc——the sum of the bending moments combined in the clockwise or counterclockwise direction in the column end section above and below the joints;
Contents of GB/T 51408-2021
Foreword ii
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Basic requirements
3.1 General requirements
3.2 Site, subgrade and foundation
3.3 Test and observation
4 Earthquake action and structure seismic isolation checking
4.1 General requirements
4.2 Design response spectrum and ground motion input
4.3 Calculation of earthquake action
4.4 Element section design
4.5 Checking for superstructure deformation
4.6 Design for seismic isolation interface
4.7 Design for substructure of isolation layer
5 Seismic isolator and isolation details
5.1 General requirements
5.2 Checking for seismic isolator
5.3 Connection of seismic isolator and structure
5.4 Isolation seam
5.5 Fixtures and piping across the seismic isolation interface
5.6 Expansion joint
5.7 Inspection and isolation identification
6 Multi-storey and tall buildings
6.1 General requirements
6.2 Design for seismic isolation interface
6.3 Structural design
7 Large-span roof buildings
7.1 General requirements
7.2 Design for seismic isolation interface
7.3 Structural design for large-span roof buildings
7.4 Supporting structure design
8 Multi-storey masonry buildings and multi-storey masonry building with R. C. frames on ground floors
8.1 General requirements
8.2 Design for seismic isolation interface
8.3 Structural design
9 Nuclear power plant buildings
9.1 General requirements
9.2 Design for seismic isolation
9.3 Floor response spectrum
9.4 Requirements for seismic isolator
9.5 Inspection rules for elastomeric seismic-protection isolators
9.6 Earthquake monitoring and alarm
10 Seismic isolation design for retrofit of existing or historic buildings
10.1 General requirements
10.2 Seismic isolation design for retrofit of existing buildings
10.3 Seismic isolation design for retrofit of historic buildings
11 Rural residential buildings
11.1 General requirements
11.2 Building isolation design essentials
Annex A Seismic performance design of seismically isolated buildings
Annex B Equations for calculating the influence coefficient for complex mode
Annex C Connection design of seismic isolator
Annex D Mechanical analysis model of seismic isolator and basic mechanical performance requirements
Annex E Underpinning methods for strengthening walls and columns of existing buildings
Explanation of wording in this standard
List of quoted standards
