GB/T 17742-2020 (GB/T17742-2020, GBT 17742-2020, GBT17742-2020) & related versions
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GB/T 17742-2020
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 91.120.25
P 15
Replacing GB/T 17742-2008
The Chinese seismic intensity scale
ISSUED ON: JULY 21, 2020
IMPLEMENTED ON: FEBRUARY 01, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
Introduction ... 5
1 Scope ... 6
2 Terms, definitions, symbols and abbreviations ... 6
3 Seismic intensity levels and the categories of buildings for which seismic
intensity is assessed ... 7
4 Seismic intensity evaluation ... 9
Appendix A (Normative) Instrumental measuring method for seismic intensity
... 18
References ... 22
The Chinese seismic intensity scale
1 Scope
This standard specifies the seismic intensity level and the category of buildings
for evaluating the seismic intensity, as well as the seismic intensity evaluation
method. Evaluation indicators include seismic damage to buildings, human
feelings, response of utensils, lifeline engineering seismic damage, other
seismic damage phenomena and seismic intensity measured by instruments.
The evaluation method is a multi-index method that comprehensively uses
macro-survey and instrumental measurement.
This standard is applicable to seismic intensity evaluation.
2 Terms, definitions, symbols and abbreviations
2.1 Terms and definitions
The following terms and definitions apply to this document.
2.1.1
Seismic intensity
The magnitude of ground motion caused by an earthquake and its impact.
2.1.2
Damage index
A quantitative indicator of the degree of seismic damage to buildings.
Note: A number between 0.00 and 1.00 indicates the degree of damage from
light to severe.
2.1.3
Mean damage index
The weighted average of the damage index of similar buildings.
Note: The mean damage index is the sum of the product of the proportion of
buildings damaged by the earthquake at all levels and the corresponding
b) "Minority" is 10% ~ 45%;
c) "Majority" is 40% ~ 70%;
d) "Most" is 60% ~ 90%;
e) "Overwhelming majority" is more than 80%.
3.3 Types of buildings for assessing intensity
The buildings used to assess the intensity include the following five types:
a) Category A1: Civil, brick, stone and wood buildings without seismic
fortification;
b) Category A2: Bucket timber frame building;
c) Category B: Brick-concrete structure without seismic fortification;
d) Category C: Brick-concrete structure buildings with seismic fortification in
accordance with degree VII (degree 7);
e) Category D: Reinforced concrete frame structure building with seismic
fortification in accordance with degree VII (degree 7).
3.4 Building damage level and its corresponding damage index
The building damage level is divided into 5 levels: basic intact, slight damage,
moderate damage, severe damage, destruction. The definition and
corresponding damage index d are as follows:
a) Basic intact: The load-bearing and non-load-bearing components are
intact, or individual non-load-bearing components are slightly damaged,
which can be used without repair. The corresponding damage index range
is 0.00 ≤ d < 0.10, which can be 0.00.
b) Slight damage: There are visible cracks in individual load-bearing
components; there are obvious cracks in non-load-bearing components.
It can be used without repair or with minor repairs. The corresponding
damage index range is 0.10 ≤ d < 0.30, which can be 0.20.
c) Moderate damage: Most load-bearing components have slight cracks; a
few have obvious cracks; some non-load-bearing components are
seriously damaged and can be used after general repairs. The
corresponding damage index range is 0.30 ≤ d < 0.55, which can be 0.40.
d) Severe damage: Most load-bearing components are seriously damaged;
non-load-bearing components partially collapsed; building repair is difficult.
The corresponding damage index range is 0.55 ≤ d < 0.85, which can be
0.70.
e) Destruction: Most of the load-bearing components are severely damaged;
the building structure is on the verge of collapse or has been destroyed;
there is no possibility of repair. The corresponding damage index range is
0.85 ≤ d ≤ 1.00, which can be 1.00.
4 Seismic intensity evaluation
4.1 Evaluation method
4.1.1 The multi-index method of macro-survey and instrument determination
can be comprehensively used in the evaluation of seismic intensity:
a) For areas that do not have the conditions for measuring seismic intensity
by instruments, macroscopic surveys shall be used to assess seismic
intensity.
b) For areas with the conditions for measuring seismic intensity by
instruments, the seismic intensity measured by instruments should be
used.
4.1.2 Evaluate the seismic intensity according to the seismic intensity levels as
classified in Table 1.
4.2 Macro-survey for evaluation of seismic intensity
4.2.1 The process of macro-survey for evaluation of seismic intensity includes
survey area and route planning, seismic damage investigation and analysis,
comprehensive determination of seismic intensity, drawing of seismic intensity
map.
4.2.2 The content of the macro-survey includes the seismic damage of buildings,
human feelings, reaction of objects, lifeline engineering seismic damage and
other seismic damage phenomena. The average damage index shall be
calculated for building seismic damage.
4.2.3 According to the survey results, comprehensively considering multiple
evaluation indicators, evaluate the seismic intensity according to Table 1.
4.2.4 When evaluating the seismic intensity through a macro-survey:
a) Degree I (degree 1) ~ degree V (degree 5) shall be based on human
perception and the reaction of utensils as the main evaluation basis;
b) Degree VI (degree 6) ~ degree X (degree 10) shall be based on the main
A.2.1 The site of the observing instrument used to obtain the ground motion
record shall refer to the provisions of 4.4 of DB/T 60-2015.
A.2.2 The frequency band range of the observing instrument used to obtain the
ground motion record shall meet the following requirements: the low-frequency
cut-off frequency is not more than 0.1 Hz; the high-frequency cut-off frequency
is not less than 10 Hz.
A.2.3 Observing instruments used to obtain ground motion records shall be
orthogonal three-dimensions; the coordinates shall be converted into east-west,
north-south and up-down components.
A.3 Baseline correction
Baseline correction processing shall be performed on the ground motion
records; the recording time process should be used to subtract the arithmetic
mean value recorded before the earthquake event. The length of the pre-event
recording time should be 10 s.
A.4 Record conversion
When the ground motion record is acceleration, it shall be converted to obtain
the speed record. When the ground motion record is speed, it shall be
converted to obtain the acceleration record.
A.5 Digital filtering
Each component of the ground motion acceleration and velocity records shall
be filtered by a digital filter of 0.1 Hz ~ 10 Hz. It should use the minimum phase
filter. The filter passband ripple shall be less than 0.5 dB; the filter out-of-band
attenuation shall be greater than 12 dB/oct.
A.6 Record synthesis
Use the formula (A.1) to calculate the three-component synthesis acceleration
record:
Where:
α (ti) - The synthesized acceleration value at the time ti, in meter per second
(m/s2);
α (ti)E-W - The east-west acceleration value after filtering at the time ti, in
meters per second (m/s2);
α (ti)N-S - The north-south acceleration value after filtering at the time ti, in
......
| Standard ID | GB/T 17742-2020 (GB/T17742-2020) | | Description (Translated English) | The Chinese seismic intensity scale | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | P15 | | Classification of International Standard | 91.120.25 | | Word Count Estimation | 14,186 | | Date of Issue | 2020-07-21 | | Date of Implementation | 2021-02-01 | | Older Standard (superseded by this standard) | GB/T 17742-2008 | | Drafting Organization | Institute of Engineering Mechanics, China Earthquake Administration, Earthquake Administration of Fujian Province, Institute of Geophysics, China Earthquake Administration, Earthquake Administration of Yunnan Province, Earthquake Administration of Xinjiang Uygur Autonomous Region, China Seismological Network Center, Institute of Geology, China Earthquake Administration, Earthquake Administration of Hebei Province, Earthquake Administration of Guangdong Province, Earthquake Administration of Sichuan Province, China Earthquake Disaster Prevention Center, Institute of Disaster Prevention Science and Technology | | Administrative Organization | National Seismological Standardization Technical Committee (SAC/TC 225) | | Proposing organization | China Earthquake Administration | | Issuing agency(ies) | State Administration for Market Regulation, National Standardization Administration |
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