GB 55001-2021 English PDF

GB 55001-2021: Unified standard for reliability design of engineering structures
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GB 55001-2021
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
UDC
P GB 55001-2021
General code for engineering structures
ISSUED ON: APRIL 09, 2021
IMPLEMENTED ON: JANUARY 01, 2022
Issued by: Ministry of Housing and Urban-Rural Development of PRC;
State Administration for Market Regulation.
Table of Contents
Foreword ... 3 
1 General ... 6 
2 Basic requirements ... 6 
2.1 Basic requirements... 6 
2.2 Safety level and design service life ... 8 
2.3 Structural analysis ... 9 
2.4 Action and combination of actions ... 10 
2.5 Material and geotechnical properties AND structural geometric parameters 11 
3 Structural design ... 12 
3.1 Design method of partial coefficient in limit state ... 12 
3.2 Other design methods ... 17 
4 Structural action ... 17 
4.1 Permanent action ... 17 
4.2 Floor and roof live loads ... 18 
4.3 Crowd load ... 24 
4.4 Crane load ... 24 
4.5 Snow load and icing load ... 25 
4.6 Wind load ... 26 
4.7 Temperature action ... 28 
4.8 Accidental actions... 29 
4.9 Water flow force and ice pressure ... 29 
4.10 The action of specialized fields ... 30 
Appendix A Symbols ... 32 
General code for engineering structures
1 General
1.0.1 In order to implement the construction policy in engineering construction,
ensure the safety, applicability, durability of the project structure, meet the
needs of normal use and green development of construction projects, this Code
is hereby formulated.
1.0.2 The engineering structure must implement this Code.
1.0.3 Whether the technical methods and measures, which are adopted in the
engineering construction, meet the requirements of this Code, shall be
determined by the relevant responsible entities. Among them, innovative
technical methods and measures shall be demonstrated AND meet the relevant
performance requirements in this Code.
2 Basic requirements
2.1 Basic requirements
2.1.1 The structure must meet the following requirements, within the design
service life:
1 It shall be able to withstand various actions, that may occur, during normal
construction and normal use;
2 It shall guarantee the intended use requirements of structures and
structural components;
3 It shall guarantee the sufficient durability requirements.
2.1.2 The structure system shall have a reasonable force transmission path,
which can transmit the various actions, that the structure may bear, from the
point of action to the force-resisting members.
2.1.3 When accidental events, such as explosions, collisions, rare earthquakes,
etc. as well as human errors, that may be encountered, the structure shall
maintain the overall stability. There shall be no destructive consequence, that
is not commensurate with the cause. In the event of a fire, the structure shall
2 Vibration, that causes discomfort for personnel OR restricts the use of the
structure;
3 Partial damage, that affects appearance, durability or structural use
function.
3.1.3 During the structural design, it shall calculate or check the limit state that
plays a control role. When the limit state of control action cannot be determined,
for the structural design, it shall calculate or check different limit states,
respectively.
3.1.4 The structural design shall distinguish the following design conditions:
1 Durable design conditions, which are suitable for the normal use of the
structure;
2 Temporary design conditions, which are suitable for temporary conditions,
such as structural construction and maintenance;
3 Accidental design conditions, which are applicable to rare situations such
as fire, explosion, abnormal collision on the structure;
4 The seismic design status, which is applicable to the situation, when the
structure is subjected to an earthquake.
3.1.5 The design conditions, which are selected during structural design, shall
cover various unfavorable conditions, during normal construction and use.
Various design conditions shall be designed for the ultimate limit state of the
bearing capacity; the enduring design conditions shall be designed for the
normal use limit state.
3.1.6 For each design situation, it shall consider a variety of different
combinations of actions, to determine the action control conditions and the most
unfavorable effect design value.
3.1.7 The combination of actions, which are used in the limit state design of the
bearing capacity, shall meet the following requirements:
1 The permanent design status and the short-term design status shall adopt
the basic combination of actions;
2 The accidental design status shall adopt the accidental combination of
actions;
3 The seismic design status shall adopt the combination actions of
earthquakes;
4 The combination of actions shall be a combination of actions, that may
taken, when it is unfavorable to the structure; the lower limit is taken, when it is
favorable for the structure.
4.1.2 The dead weight of permanent equipment, which has a fixed position,
shall be calculated, according to the weight on the equipment nameplate.
Where there is no weight on the nameplate, it shall be calculated, according to
the actual weight.
4.1.3 When the weight of the partition wall is used as a permanent action, it
shall meet the requirements of the same location. The weight of the light
partition wall, which has a flexible location, shall be considered, according to
the variable load.
4.1.4 The earth pressure shall be calculated and determined, according to the
design buried depth AND the dead weight of the soil per unit volume. The dead
weight per unit volume of the soil shall be calculated, based on different
densities, according to the calculated water level.
4.1.5 The prestressing shall consider the influence of time effect; adopt the
effective prestress.
4.2 Floor and roof live loads
4.2.1 When the equivalent uniform live load method is adopted for design, it
shall be ensured that, the load effect produced by it is equivalent to the most
unfavorable stacking situation. In the area with more or heavier stacking on the
building floor and roof, it shall consider the load, according to the actual situation.
4.2.2 The standard values of uniform live load, their combined value coefficients,
frequency coefficients, quasi-permanent value coefficients, on the floor of civil
buildings, under general use conditions, shall not be less than those specified
in Table 4.2.2. When the use load is large, the situation is special or there are
special requirements, it shall be adopted according to the actual situation.
4.2.3 The standard values of uniform live load, their combined value coefficients,
frequency coefficients, quasi-permanent value coefficients, on the floor of car
passages and passenger car parking garages, shall not be less than those
specified in Table 4.2.3. When the application conditions do not meet the
requirements of this Table, the local load of the wheel shall be converted into
an equivalent uniform load, according to the principle of effect equivalence.
4.2.12 The construction and maintenance loads shall be adopted, in
accordance with the following requirements:
1 When designing roof slabs, purlins, reinforced concrete canopies,
cantilever awnings, prefabricated beams, the standard value of the
concentrated load for construction or maintenance shall not be less than
1.0 kN; the check calculations shall be carried out at the most unfavorable
position;
2 For light components or wider components, check calculations shall be
carried out, according to actual conditions; OR it shall add temporary
facilities, such as pads and supports;
3 When calculating the bearing capacity of overhanging eaves and
overhanging awnings, a concentrated load shall be taken, every 1.0 m
along the board width. When checking the overturning of overhanging
eaves and overhanging awnings, it shall take a concentrated load, at an
interval of 2.5 m ~ 3.0 m, along the board width.
4.2.13 The standard value of the live load of the basement roof construction
shall not be less than 5.0 kN/m2. When there is a temporary accumulation load
and heavy vehicles pass by, in the construction program, it shall check and
calculate it, according to the actual load; take corresponding measures.
4.2.14 The standard value of the live load of the railings, for the stairs, stands,
balconies, accessible roofs, shall not be less than the following specified values:
1 For residences, dormitories, office buildings, hotels, hospitals, nurseries,
kindergartens, the horizontal load on the top of the railing shall be 1.0
kN/m;
2 For canteens, theaters, cinemas, stations, auditoriums, exhibition halls or
stadiums, the horizontal load on the top of the railing shall be 1.0 kN/m;
the vertical load shall be 1.2 kN/m; the horizontal and vertical loads shall
be considered separately;
3 Protective railings must be installed, on the free face of accessible roofs,
verandas, stairs, platforms, balconies, etc. of primary and secondary
schools. The horizontal load on the top of the railing shall be 1.5 kN/m; the
vertical load shall be 1.2 kN/m; the horizontal load and vertical load shall
be considered separately.
4.2.15 The combined value coefficient of construction load, maintenance load,
railing load shall be taken as 0.7; the frequent value coefficient shall be taken
as 0.5; the quasi-permanent value coefficient shall be taken as 0.
4.2.16 When the dynamic load is simplified as a static force AND then applied
vertical load shall be the maximum wheel pressure or the minimum wheel
pressure of the crane, according to the unfavorable principle; the horizontal load
shall be calculated, according to the longitudinal and lateral horizontal loads.
4.4.3 For workshops with multiple cranes, the number of cranes, which
participate in the combination, shall be calculated according to the actual
situation; the standard value of crane load shall be reduced.
4.5 Snow load and icing load
4.5.1 The standard value of snow load, on the horizontal projection surface of
the roof, shall be the product of the snow distribution coefficient of the roof area
AND the basic snow pressure.
4.5.2 The basic snow pressure shall be calculated, according to the snowfall
observation data, under open and flat terrain conditions, using an appropriate
probability distribution model, with a 50-year return period. For structures, that
are sensitive to snow loads, the snow load value shall be increased, according
to the ratio of the snow pressure to the basic snow pressure, during the 100-
year return period.
4.5.3 When determining the basic snow pressure, the annual maximum snow
pressure observation value shall be used, as the basis of analysis. Where there
is no snow pressure observation data, the calculation value of annual maximum
snow pressure shall be expressed as the product of regional average
equivalent snow density, multiplied by the observed value of annual maximum
snow depth, AND the acceleration of gravity.
4.5.4 The snow distribution coefficient of the roof shall be determined, according
to the roof form. At the same time, it shall consider various possible snow
distribution conditions, such as uniform distribution and non-uniform distribution.
When the snow sliding on the roof area is not blocked, the snow distribution
coefficient shall be 0, when the roof slope is greater than or equal to 60°.
4.5.5 When the snow distribution coefficient is adjusted, in consideration of the
favorable influence of the surrounding environment on the roof snow, the
adjustment factor shall not be lower than 0.90.
4.5.6 When calculating the icing load of tower mast structures, transmission
towers, steel cables, the load value shall be determined, according to the
thickness and the physical characteristics of the ice. To calculate the wind load
of the structure under icing conditions, it shall consider the adverse effects of
the increase in wind-shielding area and the change of wind resistance
coefficient, which are caused by icing. Meanwhile, it shall evaluate the dynamic
effects, which are caused by icing. When pedestrians may pass by below, it
shall evaluate the falling risk of icing AND take corresponding measures.
4.5.7 The combined value coefficient of the snow load shall be taken as 0.7;
the frequent value coefficient shall be taken as 0.6; the quasi-permanent value
coefficient shall be taken as 0.5, 0.2, 0, according to different climatic conditions.
4.6 Wind load
4.6.1 The standard value of wind load, which is perpendicular to the surface of
the building, shall be determined, based on the product -- of multiplying the
basic wind pressure, the wind pressure height change coefficient, the wind load
carrier form coefficient, the terrain correction coefficient, the wind direction
influence coefficient, -- considering the increase in wind load pulsation.
4.6.2 The basic wind pressure shall be calculated, based on the basic wind
speed value; its value shall not be lower than 0.30 kN/m2. The basic wind speed
shall be obtained, by uniformly converting the historical maximum wind speed
record, which is obtained under standard ground roughness conditions, INTO
the average annual maximum wind speed, at 10 m above the ground, for 10
min, using an appropriate probability distribution model, according to the 50-
year return period.
4.6.3 The wind pressure height variation coefficient shall be determined,
according to the ground roughness of the construction site. The roughness of
the ground shall be determined by factors, such as the characteristics of the
ground vegetation within a certain distance in the upwind direction of the
structure, the height of the house, the degree of density. The farthest distance
to be considered shall not be less than 20 times the height of the building AND
shall not be less than 2000 m. The standard ground roughness condition shall
be an open and flat terrain, with no shelter around; the wind pressure height
variation coefficient, at a heig...