GB 55001-2021 English PDF (GB55001-2021)
GB 55001-2021 English PDF (GB55001-2021)
GB 55001-2021: Unified standard for reliability design of engineering structures
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
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
1.0.1 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
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
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 height of 10 m, shall be 1.0.
4.6.4 The shape factor shall be determined, according to the building form, surrounding interference and other factors.
4.6.5 When the wind load amplification factor method is used, to consider the increase effect of wind load pulsation, the wind load amplification factor shall be adopted, in accordance with the following requirements:
1 The wind load amplification factor of the main stressed structure shall be determined, according to the terrain characteristics, pulsation wind
characteristics, structure period, damping ratio and other factors; its value shall not be less than 1.2;
2 The wind load amplification factor of the envelope structure shall be 4.7 Temperature action
4.7.1 For the temperature actions, it shall consider factors, such as temperature changes, solar radiation, use of heat sources, etc. The temperature action on the structure or member shall be expressed by its temperature change.
4.7.2 When calculating the temperature action effect of a structure or
component, it shall use the linear expansion coefficient of the material. 4.7.3 For the basic temperature, it shall adopt the monthly average maximum temperature and monthly average minimum temperature, during the 50-year return period. For metal structures and other structures that are more sensitive to temperature changes, it shall increase or decrease the basic temperature appropriately.
4.7.4 The standard value of the uniform temperature action shall be determined, according to the following requirements:
1 For the working condition of the maximum temperature rise of the structure, the standard value of the uniform temperature action shall be the
difference, between the highest average temperature of the structure and the lowest initial average temperature;
2 For the working condition of the maximum temperature drop of the
structure, the standard value of the uniform temperature action shall be the difference, between the lowest average temperature of the structure and the highest initial average temperature.
4.7.5 The highest average temperature and the lowest average temperature of the structure shall be determined, based on the basic temperature, according to the actual conditions during the construction period and the normal use period of the project, through the principles of thermal engineering.
4.7.6 The highest initial average temperature and the lowest initial average temperature of the structure shall be determined, according to the temperature, when the structure is closed or when the constraint is formed, OR according to the unfavorable conditions, that may occur during the construction of the structure.
4.7.7 The combined value coefficient, frequency value coefficient, quasi- permanent value coefficient of the temperature effect shall be 0.6, 0.5, 0.4, respectively.
above the water surface, it is located at 1/3 water depth below the water surface.
4.9.4 The ice load, which actions on the port engineering structure, shall be determined, according to the actual situation of the local ice slush AND the structural form of the port engineering. For important projects OR the ice load that is difficult to calculate and determine, it shall be determined through special research, such as ice force physical model tests.
4.9.5 The point of action of static ice pressure shall be 1/3 of the ice thickness, below the ice surface.
4.9.6 The ice pressure and water pressure, within the thickness of the ice layer, during freezing period, shall not be considered at the same time.
4.10 The action of specialized fields
4.10.1 The aerodynamic pressure and aerodynamic suction, which are caused by the railway train, shall be applied to the affected building structure, as a moving surface load.
4.10.2 During the design of highway pavement, bridges, culverts, the vehicle load shall be determined, according to the highway grade, vehicle technical indicators, load patterns. The vehicle load, which actions on the port
engineering structure, shall be determined, according to the actual vehicle type selected; AND arranged according to the possible situations.
4.10.3 For tunnels, in areas where the average temperature of the coldest month is lower than -15 ??C, as well as the structures, which are located in permafrost and frost heaving soil (seasonal frost heaving depth greater than 2 m), it shall consider the frost heaving force. The frost heave force shall be determined, through research, based on local natural conditions, winter water content of surrounding rocks, drainage conditions.
4.10.4 The standard value of the stacking load, which actions on the port engineering structure, shall be determined, through comprehensive analysis, according to the stacking conditions, which are determined by the types of stacks and loading and unloading processes, combined with the structure form of the wharf, foundation conditions, structural calculation items, considering the port development.
4.10.5 The wave force, which is borne by ports and hydraulic structures, shall be calculated and determined, according to different structural forms such as straight wall type, slope type, pile foundation and pier column, high-pile wharf panel, etc., combined with wave form and action mode. When the structure or