Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This code is developed by Guangdong Provincial Academy of Building Research with the relevant organizations, based on the requirements of Guangdong Provincial Department of Construction's "Notice on issuing the development task of Guangdong provincial standard Load code for the design of building structures" (YUEJIANKEHAN [2009] No.438), in combination with the specific situation that the national standard GB 50009-2012 Load code for the design of building structures has been implemented since October 1, 2012, and through careful summary of the scientific research achievements, design experience and engineering practice experience of Guangdong province.
This code consists of 10 clauses and 12 annexes. The main technical contents include general provisions, terms and symbols, classification and combination of loads, permanent load, live load on floors and roofs, crane load, wind load, thermal action, accidental load and other load.
Compared with the national standard GB 50009-2012 Load code for the design of building structures, the main technical content revised in this code according to the situation of Guangdong province is as follows: 1. The partial coefficients of fire engine load, construction pre-loading and thermal action are stipulated; 2. The nominal value of uniform live load on the floor and roof of some special buildings and its combination value coefficient, frequent value coefficient and quasi-permanent value coefficient are supplemented, and the provisions of construction loads are supplemented; 3. The relevant provisions of wind direction coefficient are supplemented; 4. The reference wind pressure in all counties and cities of Guangdong province are supplemented; 5. The wind load shape factors are supplemented; 6. The wind load of envelope structure is adjusted; the local shape factor of louver and double-layer curtain wall are supplemented; the provisions of shape factor and internal pressure coefficient of buildings in typhoon area and construction stage are supplemented; the gustiness factors in typhoon area and non-typhoon area are specified respectively; the wind vibration coefficient of flexible structure is specified; 7. The wind induced along-wind vibration and wind vibration coefficient, cross-wind and torsional vibration are combined and adjusted to wind vibration of high-rise structure, and the calculation conditions of equivalent static wind load in crosswind according to Annex H.2 are modified, and the load combination condition table is modified; 8. The wind vibration of roof structure is added; 9. The provisions of concrete structures sensitive to thermal action and large-section closed steel structural members exposed to outdoor are added; 10. The other loads in Clause 10 are added; 11. The fire engine load values are added in Annex B; 12. The reference wind pressure distribution diagram of the whole province, Guangzhou, Shenzhen, Dongguan and Zhongshan are added in Annex E; 13. The judging method of the terrain roughness category is added in Annex K, technical guidance for wind tunnel test added in Annex L, and wind vibration coefficient of unilateral independence cantilevered roof added in Annex M.
The provisions printed in bold type in this code are compulsory and must be enforced strictly.
Guangdong Provincial Department of Housing and Urban-Rural Development is in charge of the administration of this code, and Guangdong Provincial Academy of Building Research is responsible for the explanation of mandatory provisions and specific technical contents.
Contents
1 General provisions 1
2 Terms and symbols 1
2.1 Terms 1
2.2 Symbols 5
3 Classification and combination of loads 9
3.1 Classification of loads and representative values of loads 9
3.2 Combination of loads 10
4 Permanent load 15
5 Live load on floors and roofs 15
5.1 Uniformly distributed live loads on floors in civil buildings 15
5.2 Live loads on floors in industrial buildings 23
5.3 Live loads on roofs 23
5.4 Ash load on roofs 25
5.5 Construction and maintenance loads and horizontal and vertical loads on railings 27
5.6 Dynamic coefficient 28
6 Crane load 28
6.1 Vertical and horizontal crane loads 28
6.2 Combination of multi-cranes 29
6.3 Dynamic coefficients of crane loads 30
6.4 Combination value, frequent value and quasi-permanent value of crane load 30
7 Wind load 31
7.1 Characteristic value of wind load and reference wind pressure 31
7.2 Exposure factor for wind pressure 35
7.3 Shape factor of wind load 38
7.4 Wind load of building envelope 58
7.5 Wind vibration of high-rise structure 66
7.6 Wind vibration of roof structure 72
8 Thermal action 73
8.1 General 73
8.2 Reference air temperature 74
8.3 Uniform thermal action 74
9 Accidental loads 75
9.1 General 75
9.2 Explosion 75
9.3 Impact 76
10 Other loads 78
10.1 Load of footbridge 78
10.2 Water pressure of underground structure 78
10.3 Snow load 79
Annex A Self-weight and classification of commonly used materials and structural members 80
Annex B Live load values of fire engine taking different slab span and influence of covered soil thickness under consideration 97
Annex C Determine method of equivalent uniformly distributed live loads on floors 100
Annex D Live loads on floors of industrial buildings 105
Annex E Determination method of reference snow pressure, wind pressure and temperature 113
Annex F Empirical formula for fundamental natural period of structure 123
Annex G Approximate mode shape coefficient of structure 127
Annex H Equivalent wind load for cross-wind and torsional vibration 129
Annex J Acceleration of along-wind and cross-wind vibration for high-rise buildings 138
Annex K Judging method of terrain roughness category 141
Annex L Wind tunnel test guidelines 145
Annex M Wind vibration coefficient of unilateral independence cantilevered roof 146
Explanation of wording in this code 147
List of quoted codes 148
Load code for the design of building structures
1 General provisions
1.0.1 This code is developed with a view to meeting the needs of building structure design in Guangdong province and meeting the requirements of safety, applicability, economy and rationality.
1.0.2 This code is applicable to the structural design of constructional engineering in Guangdong province.
1.0.3 This code is developed according to the basic criteria set out in the national standard GB 50153-2008 Unified standard for reliability design of engineering structures.
1.0.4 The actions involved in the design of building structures include direct actions (loads) and indirect actions. This code only specifies loads and thermal actions, and the provisions on variable load are also applicable to thermal actions.
1.0.5 In addition to those specified in this code, the loads involved in the design of building structures shall also comply with those specified in the current relevant standards of the Nation and Guangdong province.
2 Terms and symbols
2.1 Terms
2.1.1 permanent load
load whose value does not change with time, or whose change is negligible compared with the average, or whose change is monotonous and can tend to the limit during the service life of structure
2.1.2 variable load
load whose value changes with time and whose change cannot be ignored compared with the average during the service life of structure
2.1.3 accidental load
load that does not necessarily occur in the design service life of structure, but once occurred, its magnitude is very large and its duration is very short
2.1.4 representative values of a load
load values used to check the limit state in design, such as nominal value, combination value, frequent value and quasi-permanent value
2.1.5 design reference period
time selected to determine the representative value of variable load
2.1.6 characteristic value/nominal value
basic representative value of a load, which is the characteristic value of the statistical distribution of the maximum load in the design reference period (such as average, mode, median or tantile)
2.1.7 combination value
value of variable load making the exceeding probability of the combined load effect in the design reference period be consistent with the corresponding probability when the load appears alone, or making the combined structure have uniformly specified reliable index
2.1.8 frequent value
value of variable load of which the total exceeding time is the specified smaller ratio or the exceeding frequency is the specified frequency within the design reference period
2.1.9 quasi-permanent value
value of variable load of which the total exceeding time is about half of the design reference period within the design reference period
2.1.10 design value of a load
product of the representative value of a load and the partial coefficient for load
2.1.11 load effect
reaction of structure or structural member caused by load, such as internal force, deformation and crack
2.1.12 load combination
provisions for the design values of various loads appearing at the same time when designing according to the limit state, in order to ensure the reliability of the structure
2.1.13 fundamental combination
combination of permanent action and variable action when calculating the ultimate limit state
2.1.14 accidental combination
combination of permanent load, variable load and accidental load when calculating the ultimate limit state, and the combination of permanent load and variable load when checking the overall stability of damaged structures after accidental event
2.1.15 characteristic/ nominal combination
combination adopting the nominal value or combination value as the representative value of a load when calculating the limit state of normal use
2.1.16 frequent combination
combination adopting the frequent value or quasi-permanent value as the representative value of load for variable loads when calculating the limit state of normal use
2.1.17 quasi-permanent combination
combination adopting the quasi-permanent value as the representative value of load for variable loads when calculating the limit state of normal use
2.1.18 equivalent uniform live load
actual load distributed discontinuously on the floor in structural design, which is generally replaced by equivalent uniform live load; the equivalent uniform live load refers to the uniformly distributed load whose load effect on the structure can be consistent with the actual load effect
2.1.19 tributary area
floor area used to calculate the load of members in consideration of the deduction of uniformly distributed load of beams, columns and other members
2.1.20 dynamic coefficient
equivalent coefficient of a structure or member subjected to dynamic load adopted for static design; its value is the ratio of the maximum dynamic effect of the structure or member to the corresponding static effect
2.1.21 reference snow pressure
reference pressure of snow load, which is generally determined by the maximum value once every 50 years obtained through probability statistics of the observed data of snow self-weight on the local open flat ground
2.1.22 reference wind pressure
reference pressure of wind load, which is generally determined using the Bernoulli equation (E.2.4) by the maximum value once every 50 years obtained through probability statistics of the observed data of the average wind speed within 10min at a height of 10m above the local open flat ground, in consideration of the corresponding air density
2.1.23 terrain roughness
grade used to describe the distribution of irregular obstacles on the ground, when the wind blows over the ground within 2km before reaching the structure
2.1.24 thermal action
action caused by temperature change in structure or structural member
2.1.25 shade air temperature
temperature measured in a standard louver box and recorded in hours
2.1.26 reference air temperature
reference value of temperature, which is determined through statistics according to the average value of the highest temperature in the month with the highest temperature and the average value of the lowest temperature in the month with the lowest temperature in the past years, based on the monthly average maximum temperature and monthly average minimum temperature once every 50 years
2.1.27 uniform temperature
constant temperature throughout the cross section of the structural member, which dominates expansion or contraction of structural member
2.1.28 initial temperature
temperature at which a structure forms an integrally restrained structural system at a certain stage of construction, which is also called the closure temperature
2.1.29 wind direction coefficient
correction factor for different azimuth of wind pressure in different recurrence intervals, in consideration of the joint probability distribution of wind speed and wind direction, which is usually used in combination with wind tunnel test data
2.2 Symbols
2.2.1 Representative values of a load and load combination
Ad——the characteristic value of accidental load;
C——the specified limit of structure or member in normal use;
Gk——the characteristic value of permanent load;
Qk——the characteristic value of variable load;
Rd——the design resistance value of structural member
SAd——the characteristic value of accidental load effect;
SGk——the characteristic value of permanent load effect;
SQk——the characteristic value of variable load effect;
Sd——the design value of load effect combination;
γ0——the structural importance factor;
γG——the partial coefficient of permanent load;
γQ——the partial coefficient of variable load;
γLj——the adjustment factor of variable load with design service life taken into consideration;
ψc——the combination value coefficient of variable load;
ψf ——the frequent value coefficient of variable load;
ψq ——the quasi-permanent value coefficient of variable load.
2.2.2 Wind loads
αD, Z——the acceleration of wind induced along-wind vibration of high-rise buildings at z height (m/s2);
αL, z——the acceleration of wind induced across-wind vibration of high-rise buildings at z height (m/s2);
B——the width of windward side of structure;
Bz——the background component factor of the fluctuating wind load;
C′L——the across-wind wind factor;
C′T——the wind-induced torque coefficient;
Cm——the angle edge correction factor of across-wind wind;
Csm——the angle edge correction factor of across-wind wind power spectrum;
D——the plane depth (along-wind dimension) or diameter of structure;
f1—— the first-order natural frequency of the structure;
fT1—— the first-order torsional natural frequency of the structure;
——the conversion frequency;
——the torsional conversion frequency;
FDk——the characteristic value of along-wind wind per unit height;
FLk——the characteristic value of across-wind wind per unit height;
TTk——the characteristic value of wind-induced torque per unit height;
g——the gravitational acceleration, or peak factor;
H——the height of the top of the structure or mountain;
I10——the nominal turbulence intensity of wind at 10m high;
KL——the across-wind mode correction factor;
KT——the torsional mode correction factor;
R——the resonant component factor of the fluctuating wind load;
RL——the wind induced across-wind vibration resonance factor;
RT——the wind induced torsional vibration resonance factor;
Re——the Reynolds number;
St——the Strouhal number;
T1——the first-order natural vibration period of the structure;
TL1——the first-order across-wind natural vibration period of the structure;
TT1——the first-order torsional natural vibration period of the structure;
w0——the reference wind pressure;
wk——the characteristic value of wind load;
wLk——the characteristic value of equivalent wind load for across-wind vibration;
wTk——the characteristic value of equivalent wind load for torsional vibration;
α——the angle of gradient, or wind speed profile index;
βz——the wind vibration coefficient at the height of z;
βgz——the gustiness factor;
vcr——the critical wind speed of across-wind resonance;
vH——the wind speed at the top of the structure;
μz——the exposure factor for wind pressure;
μs——the shape factor of wind load;
μs1——the local shape factor of wind load;
μ′s1——the local shape factor of louver wind load;
η——the wind load topography and landform correction factor;
ηa——the fluctuation coefficient of acceleration of wind induced along-wind vibration;
——the air density;
ρx, ρz——the correlation coefficient of fluctuating wind load in horizontal direction and vertical direction;
z——the structural mode shape coefficient;
ζ——the structural damping ratio;
ζa——the across-wind aerodynamic damping ratio.
2.2.3 Thermal action
Tmax, Tmin——the monthly average maximum temperature and monthly average minimum temperature;
Ts, max, Ts, min——the highest average temperature of structure and the lowest average temperature of structure;
T0, max, T0, min——the highest initial temperature of structure and the lowest initial temperature of structure;
Tk——the characteristic value of uniform temperature action;
αT——the linear expansion factor of material.
2.2.4 Accidental load
AV——the area of through-hole plate (m2);
Kdc——the dynamic coefficient for calculating equivalent uniform static load of explosion;
m——the mass of automotive or helicopter;
Pk——the characteristic value of impact load;
pc——the maximum pressure of uniform dynamic load of explosion;
pv——the approved failure pressure of through-hole plate;
qce——the characteristic value of equivalent uniform static load of explosion;
t——the impact time;
v——the automotive speed;
V——the volume of explosion space.
2.2.5 Other loads
W——the crowd load per unit area;
L——the loading length;
B——the width of half bridge;
Sk——the characteristic value of snow load;
S0——the reference snow pressure;
μr——the snow distribution coefficient of roof;
ρ ——the snow density.
3 Classification and combination of loads
3.1 Classification of loads and representative values of loads
3.1.1 Loads on building structures may be classified into the following three categories:
1 Permanent load, including self-weight of structure, soil pressure, prestress, etc.
2 Variable load, including live load on floor, live load on roof and dust load, crane load, wind load, snow load, fire engine load, thermal action, construction pre-loading, building maintenance unit (BMU) load during work, roof helicopter load, etc.
3 Accidental load, including explosive force, impact force, etc.
3.1.2 When designing the building structures, different representative values shall be adopted for different loads according to the following requirements:
1 For permanent load, characteristic value shall be adopted as the representative value.
2 For variable load, characteristic value, combination value, frequent value or quasi-permanent value shall be adopted as the representative value according to design requirements.
3 The representative value of accidental load shall be determined according to the characteristics of building structures.
3.1.3 The design reference period of 50 years shall be adopted for determining the representative value of variable load.
3.1.4 The characteristic value of load shall be adopted according to the requirements of each clause of this code.
3.1.5 When the ultimate limit state or the serviceability limit state is designed according to characteristic combination, the load combination value or characteristic value shall be adopted as the representative value for variable load according to the specified load combination. The combination value of variable load shall be the characteristic value of variable load multiplied by the combination value coefficient of load.
3.1.6 When the serviceability limit state is designed according to frequent combination, the frequent value or quasi-permanent value of variable load shall be adopted as its load representative value; when it is designed according to the quasi-permanent combination, the quasi-permanent value of variable load shall be adopted as its load representative value. The frequent value of variable load shall be the characteristic value of variable load multiplied by the frequent value coefficient. The quasi-permanent value of variable load shall be the characteristic value of variable load multiplied by the quasi-permanent value coefficient.
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Classification and combination of loads
3.1 Classification of loads and representative values of loads
3.2 Combination of loads
4 Permanent load
5 Live load on floors and roofs
5.1 Uniformly distributed live loads on floors in civil buildings
5.2 Live loads on floors in industrial buildings
5.3 Live loads on roofs
5.4 Ash load on roofs
5.5 Construction and maintenance loads and horizontal and vertical loads on railings
5.6 Dynamic coefficient
6 Crane load
6.1 Vertical and horizontal crane loads
6.2 Combination of multi-cranes
6.3 Dynamic coefficients of crane loads
6.4 Combination value, frequent value and quasi-permanent value of crane load
7 Wind load
7.1 Characteristic value of wind load and reference wind pressure
7.2 Exposure factor for wind pressure
7.3 Shape factor of wind load
7.4 Wind load of building envelope
7.5 Wind vibration of high-rise structure
7.6 Wind vibration of roof structure
8 Thermal action
8.1 General
8.2 Reference air temperature
8.3 Uniform thermal action
9 Accidental loads
9.1 General
9.2 Explosion
9.3 Impact
10 Other loads
10.1 Load of footbridge
10.2 Water pressure of underground structure
10.3 Snow load
Annex A Self-weight and classification of commonly used materials and structural members
Annex B Live load values of fire engine taking different slab span and influence of covered soil thickness under consideration
Annex C Determine method of equivalent uniformly distributed live loads on floors
Annex D Live loads on floors of industrial buildings
Annex E Determination method of reference snow pressure, wind pressure and temperature
Annex F Empirical formula for fundamental natural period of structure
Annex G Approximate mode shape coefficient of structure
Annex H Equivalent wind load for cross-wind and torsional vibration
Annex J Acceleration of along-wind and cross-wind vibration for high-rise buildings
Annex K Judging method of terrain roughness category
Annex L Wind tunnel test guidelines
Annex M Wind vibration coefficient of unilateral independence cantilevered roof
Explanation of wording in this code
List of quoted codes
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This code is developed by Guangdong Provincial Academy of Building Research with the relevant organizations, based on the requirements of Guangdong Provincial Department of Construction's "Notice on issuing the development task of Guangdong provincial standard Load code for the design of building structures" (YUEJIANKEHAN [2009] No.438), in combination with the specific situation that the national standard GB 50009-2012 Load code for the design of building structures has been implemented since October 1, 2012, and through careful summary of the scientific research achievements, design experience and engineering practice experience of Guangdong province.
This code consists of 10 clauses and 12 annexes. The main technical contents include general provisions, terms and symbols, classification and combination of loads, permanent load, live load on floors and roofs, crane load, wind load, thermal action, accidental load and other load.
Compared with the national standard GB 50009-2012 Load code for the design of building structures, the main technical content revised in this code according to the situation of Guangdong province is as follows: 1. The partial coefficients of fire engine load, construction pre-loading and thermal action are stipulated; 2. The nominal value of uniform live load on the floor and roof of some special buildings and its combination value coefficient, frequent value coefficient and quasi-permanent value coefficient are supplemented, and the provisions of construction loads are supplemented; 3. The relevant provisions of wind direction coefficient are supplemented; 4. The reference wind pressure in all counties and cities of Guangdong province are supplemented; 5. The wind load shape factors are supplemented; 6. The wind load of envelope structure is adjusted; the local shape factor of louver and double-layer curtain wall are supplemented; the provisions of shape factor and internal pressure coefficient of buildings in typhoon area and construction stage are supplemented; the gustiness factors in typhoon area and non-typhoon area are specified respectively; the wind vibration coefficient of flexible structure is specified; 7. The wind induced along-wind vibration and wind vibration coefficient, cross-wind and torsional vibration are combined and adjusted to wind vibration of high-rise structure, and the calculation conditions of equivalent static wind load in crosswind according to Annex H.2 are modified, and the load combination condition table is modified; 8. The wind vibration of roof structure is added; 9. The provisions of concrete structures sensitive to thermal action and large-section closed steel structural members exposed to outdoor are added; 10. The other loads in Clause 10 are added; 11. The fire engine load values are added in Annex B; 12. The reference wind pressure distribution diagram of the whole province, Guangzhou, Shenzhen, Dongguan and Zhongshan are added in Annex E; 13. The judging method of the terrain roughness category is added in Annex K, technical guidance for wind tunnel test added in Annex L, and wind vibration coefficient of unilateral independence cantilevered roof added in Annex M.
The provisions printed in bold type in this code are compulsory and must be enforced strictly.
Guangdong Provincial Department of Housing and Urban-Rural Development is in charge of the administration of this code, and Guangdong Provincial Academy of Building Research is responsible for the explanation of mandatory provisions and specific technical contents.
Contents
1 General provisions 1
2 Terms and symbols 1
2.1 Terms 1
2.2 Symbols 5
3 Classification and combination of loads 9
3.1 Classification of loads and representative values of loads 9
3.2 Combination of loads 10
4 Permanent load 15
5 Live load on floors and roofs 15
5.1 Uniformly distributed live loads on floors in civil buildings 15
5.2 Live loads on floors in industrial buildings 23
5.3 Live loads on roofs 23
5.4 Ash load on roofs 25
5.5 Construction and maintenance loads and horizontal and vertical loads on railings 27
5.6 Dynamic coefficient 28
6 Crane load 28
6.1 Vertical and horizontal crane loads 28
6.2 Combination of multi-cranes 29
6.3 Dynamic coefficients of crane loads 30
6.4 Combination value, frequent value and quasi-permanent value of crane load 30
7 Wind load 31
7.1 Characteristic value of wind load and reference wind pressure 31
7.2 Exposure factor for wind pressure 35
7.3 Shape factor of wind load 38
7.4 Wind load of building envelope 58
7.5 Wind vibration of high-rise structure 66
7.6 Wind vibration of roof structure 72
8 Thermal action 73
8.1 General 73
8.2 Reference air temperature 74
8.3 Uniform thermal action 74
9 Accidental loads 75
9.1 General 75
9.2 Explosion 75
9.3 Impact 76
10 Other loads 78
10.1 Load of footbridge 78
10.2 Water pressure of underground structure 78
10.3 Snow load 79
Annex A Self-weight and classification of commonly used materials and structural members 80
Annex B Live load values of fire engine taking different slab span and influence of covered soil thickness under consideration 97
Annex C Determine method of equivalent uniformly distributed live loads on floors 100
Annex D Live loads on floors of industrial buildings 105
Annex E Determination method of reference snow pressure, wind pressure and temperature 113
Annex F Empirical formula for fundamental natural period of structure 123
Annex G Approximate mode shape coefficient of structure 127
Annex H Equivalent wind load for cross-wind and torsional vibration 129
Annex J Acceleration of along-wind and cross-wind vibration for high-rise buildings 138
Annex K Judging method of terrain roughness category 141
Annex L Wind tunnel test guidelines 145
Annex M Wind vibration coefficient of unilateral independence cantilevered roof 146
Explanation of wording in this code 147
List of quoted codes 148
Load code for the design of building structures
1 General provisions
1.0.1 This code is developed with a view to meeting the needs of building structure design in Guangdong province and meeting the requirements of safety, applicability, economy and rationality.
1.0.2 This code is applicable to the structural design of constructional engineering in Guangdong province.
1.0.3 This code is developed according to the basic criteria set out in the national standard GB 50153-2008 Unified standard for reliability design of engineering structures.
1.0.4 The actions involved in the design of building structures include direct actions (loads) and indirect actions. This code only specifies loads and thermal actions, and the provisions on variable load are also applicable to thermal actions.
1.0.5 In addition to those specified in this code, the loads involved in the design of building structures shall also comply with those specified in the current relevant standards of the Nation and Guangdong province.
2 Terms and symbols
2.1 Terms
2.1.1 permanent load
load whose value does not change with time, or whose change is negligible compared with the average, or whose change is monotonous and can tend to the limit during the service life of structure
2.1.2 variable load
load whose value changes with time and whose change cannot be ignored compared with the average during the service life of structure
2.1.3 accidental load
load that does not necessarily occur in the design service life of structure, but once occurred, its magnitude is very large and its duration is very short
2.1.4 representative values of a load
load values used to check the limit state in design, such as nominal value, combination value, frequent value and quasi-permanent value
2.1.5 design reference period
time selected to determine the representative value of variable load
2.1.6 characteristic value/nominal value
basic representative value of a load, which is the characteristic value of the statistical distribution of the maximum load in the design reference period (such as average, mode, median or tantile)
2.1.7 combination value
value of variable load making the exceeding probability of the combined load effect in the design reference period be consistent with the corresponding probability when the load appears alone, or making the combined structure have uniformly specified reliable index
2.1.8 frequent value
value of variable load of which the total exceeding time is the specified smaller ratio or the exceeding frequency is the specified frequency within the design reference period
2.1.9 quasi-permanent value
value of variable load of which the total exceeding time is about half of the design reference period within the design reference period
2.1.10 design value of a load
product of the representative value of a load and the partial coefficient for load
2.1.11 load effect
reaction of structure or structural member caused by load, such as internal force, deformation and crack
2.1.12 load combination
provisions for the design values of various loads appearing at the same time when designing according to the limit state, in order to ensure the reliability of the structure
2.1.13 fundamental combination
combination of permanent action and variable action when calculating the ultimate limit state
2.1.14 accidental combination
combination of permanent load, variable load and accidental load when calculating the ultimate limit state, and the combination of permanent load and variable load when checking the overall stability of damaged structures after accidental event
2.1.15 characteristic/ nominal combination
combination adopting the nominal value or combination value as the representative value of a load when calculating the limit state of normal use
2.1.16 frequent combination
combination adopting the frequent value or quasi-permanent value as the representative value of load for variable loads when calculating the limit state of normal use
2.1.17 quasi-permanent combination
combination adopting the quasi-permanent value as the representative value of load for variable loads when calculating the limit state of normal use
2.1.18 equivalent uniform live load
actual load distributed discontinuously on the floor in structural design, which is generally replaced by equivalent uniform live load; the equivalent uniform live load refers to the uniformly distributed load whose load effect on the structure can be consistent with the actual load effect
2.1.19 tributary area
floor area used to calculate the load of members in consideration of the deduction of uniformly distributed load of beams, columns and other members
2.1.20 dynamic coefficient
equivalent coefficient of a structure or member subjected to dynamic load adopted for static design; its value is the ratio of the maximum dynamic effect of the structure or member to the corresponding static effect
2.1.21 reference snow pressure
reference pressure of snow load, which is generally determined by the maximum value once every 50 years obtained through probability statistics of the observed data of snow self-weight on the local open flat ground
2.1.22 reference wind pressure
reference pressure of wind load, which is generally determined using the Bernoulli equation (E.2.4) by the maximum value once every 50 years obtained through probability statistics of the observed data of the average wind speed within 10min at a height of 10m above the local open flat ground, in consideration of the corresponding air density
2.1.23 terrain roughness
grade used to describe the distribution of irregular obstacles on the ground, when the wind blows over the ground within 2km before reaching the structure
2.1.24 thermal action
action caused by temperature change in structure or structural member
2.1.25 shade air temperature
temperature measured in a standard louver box and recorded in hours
2.1.26 reference air temperature
reference value of temperature, which is determined through statistics according to the average value of the highest temperature in the month with the highest temperature and the average value of the lowest temperature in the month with the lowest temperature in the past years, based on the monthly average maximum temperature and monthly average minimum temperature once every 50 years
2.1.27 uniform temperature
constant temperature throughout the cross section of the structural member, which dominates expansion or contraction of structural member
2.1.28 initial temperature
temperature at which a structure forms an integrally restrained structural system at a certain stage of construction, which is also called the closure temperature
2.1.29 wind direction coefficient
correction factor for different azimuth of wind pressure in different recurrence intervals, in consideration of the joint probability distribution of wind speed and wind direction, which is usually used in combination with wind tunnel test data
2.2 Symbols
2.2.1 Representative values of a load and load combination
Ad——the characteristic value of accidental load;
C——the specified limit of structure or member in normal use;
Gk——the characteristic value of permanent load;
Qk——the characteristic value of variable load;
Rd——the design resistance value of structural member
SAd——the characteristic value of accidental load effect;
SGk——the characteristic value of permanent load effect;
SQk——the characteristic value of variable load effect;
Sd——the design value of load effect combination;
γ0——the structural importance factor;
γG——the partial coefficient of permanent load;
γQ——the partial coefficient of variable load;
γLj——the adjustment factor of variable load with design service life taken into consideration;
ψc——the combination value coefficient of variable load;
ψf ——the frequent value coefficient of variable load;
ψq ——the quasi-permanent value coefficient of variable load.
2.2.2 Wind loads
αD, Z——the acceleration of wind induced along-wind vibration of high-rise buildings at z height (m/s2);
αL, z——the acceleration of wind induced across-wind vibration of high-rise buildings at z height (m/s2);
B——the width of windward side of structure;
Bz——the background component factor of the fluctuating wind load;
C′L——the across-wind wind factor;
C′T——the wind-induced torque coefficient;
Cm——the angle edge correction factor of across-wind wind;
Csm——the angle edge correction factor of across-wind wind power spectrum;
D——the plane depth (along-wind dimension) or diameter of structure;
f1—— the first-order natural frequency of the structure;
fT1—— the first-order torsional natural frequency of the structure;
——the conversion frequency;
——the torsional conversion frequency;
FDk——the characteristic value of along-wind wind per unit height;
FLk——the characteristic value of across-wind wind per unit height;
TTk——the characteristic value of wind-induced torque per unit height;
g——the gravitational acceleration, or peak factor;
H——the height of the top of the structure or mountain;
I10——the nominal turbulence intensity of wind at 10m high;
KL——the across-wind mode correction factor;
KT——the torsional mode correction factor;
R——the resonant component factor of the fluctuating wind load;
RL——the wind induced across-wind vibration resonance factor;
RT——the wind induced torsional vibration resonance factor;
Re——the Reynolds number;
St——the Strouhal number;
T1——the first-order natural vibration period of the structure;
TL1——the first-order across-wind natural vibration period of the structure;
TT1——the first-order torsional natural vibration period of the structure;
w0——the reference wind pressure;
wk——the characteristic value of wind load;
wLk——the characteristic value of equivalent wind load for across-wind vibration;
wTk——the characteristic value of equivalent wind load for torsional vibration;
α——the angle of gradient, or wind speed profile index;
βz——the wind vibration coefficient at the height of z;
βgz——the gustiness factor;
vcr——the critical wind speed of across-wind resonance;
vH——the wind speed at the top of the structure;
μz——the exposure factor for wind pressure;
μs——the shape factor of wind load;
μs1——the local shape factor of wind load;
μ′s1——the local shape factor of louver wind load;
η——the wind load topography and landform correction factor;
ηa——the fluctuation coefficient of acceleration of wind induced along-wind vibration;
——the air density;
ρx, ρz——the correlation coefficient of fluctuating wind load in horizontal direction and vertical direction;
z——the structural mode shape coefficient;
ζ——the structural damping ratio;
ζa——the across-wind aerodynamic damping ratio.
2.2.3 Thermal action
Tmax, Tmin——the monthly average maximum temperature and monthly average minimum temperature;
Ts, max, Ts, min——the highest average temperature of structure and the lowest average temperature of structure;
T0, max, T0, min——the highest initial temperature of structure and the lowest initial temperature of structure;
Tk——the characteristic value of uniform temperature action;
αT——the linear expansion factor of material.
2.2.4 Accidental load
AV——the area of through-hole plate (m2);
Kdc——the dynamic coefficient for calculating equivalent uniform static load of explosion;
m——the mass of automotive or helicopter;
Pk——the characteristic value of impact load;
pc——the maximum pressure of uniform dynamic load of explosion;
pv——the approved failure pressure of through-hole plate;
qce——the characteristic value of equivalent uniform static load of explosion;
t——the impact time;
v——the automotive speed;
V——the volume of explosion space.
2.2.5 Other loads
W——the crowd load per unit area;
L——the loading length;
B——the width of half bridge;
Sk——the characteristic value of snow load;
S0——the reference snow pressure;
μr——the snow distribution coefficient of roof;
ρ ——the snow density.
3 Classification and combination of loads
3.1 Classification of loads and representative values of loads
3.1.1 Loads on building structures may be classified into the following three categories:
1 Permanent load, including self-weight of structure, soil pressure, prestress, etc.
2 Variable load, including live load on floor, live load on roof and dust load, crane load, wind load, snow load, fire engine load, thermal action, construction pre-loading, building maintenance unit (BMU) load during work, roof helicopter load, etc.
3 Accidental load, including explosive force, impact force, etc.
3.1.2 When designing the building structures, different representative values shall be adopted for different loads according to the following requirements:
1 For permanent load, characteristic value shall be adopted as the representative value.
2 For variable load, characteristic value, combination value, frequent value or quasi-permanent value shall be adopted as the representative value according to design requirements.
3 The representative value of accidental load shall be determined according to the characteristics of building structures.
3.1.3 The design reference period of 50 years shall be adopted for determining the representative value of variable load.
3.1.4 The characteristic value of load shall be adopted according to the requirements of each clause of this code.
3.1.5 When the ultimate limit state or the serviceability limit state is designed according to characteristic combination, the load combination value or characteristic value shall be adopted as the representative value for variable load according to the specified load combination. The combination value of variable load shall be the characteristic value of variable load multiplied by the combination value coefficient of load.
3.1.6 When the serviceability limit state is designed according to frequent combination, the frequent value or quasi-permanent value of variable load shall be adopted as its load representative value; when it is designed according to the quasi-permanent combination, the quasi-permanent value of variable load shall be adopted as its load representative value. The frequent value of variable load shall be the characteristic value of variable load multiplied by the frequent value coefficient. The quasi-permanent value of variable load shall be the characteristic value of variable load multiplied by the quasi-permanent value coefficient.
Contents of DBJ 15-101-2014
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Classification and combination of loads
3.1 Classification of loads and representative values of loads
3.2 Combination of loads
4 Permanent load
5 Live load on floors and roofs
5.1 Uniformly distributed live loads on floors in civil buildings
5.2 Live loads on floors in industrial buildings
5.3 Live loads on roofs
5.4 Ash load on roofs
5.5 Construction and maintenance loads and horizontal and vertical loads on railings
5.6 Dynamic coefficient
6 Crane load
6.1 Vertical and horizontal crane loads
6.2 Combination of multi-cranes
6.3 Dynamic coefficients of crane loads
6.4 Combination value, frequent value and quasi-permanent value of crane load
7 Wind load
7.1 Characteristic value of wind load and reference wind pressure
7.2 Exposure factor for wind pressure
7.3 Shape factor of wind load
7.4 Wind load of building envelope
7.5 Wind vibration of high-rise structure
7.6 Wind vibration of roof structure
8 Thermal action
8.1 General
8.2 Reference air temperature
8.3 Uniform thermal action
9 Accidental loads
9.1 General
9.2 Explosion
9.3 Impact
10 Other loads
10.1 Load of footbridge
10.2 Water pressure of underground structure
10.3 Snow load
Annex A Self-weight and classification of commonly used materials and structural members
Annex B Live load values of fire engine taking different slab span and influence of covered soil thickness under consideration
Annex C Determine method of equivalent uniformly distributed live loads on floors
Annex D Live loads on floors of industrial buildings
Annex E Determination method of reference snow pressure, wind pressure and temperature
Annex F Empirical formula for fundamental natural period of structure
Annex G Approximate mode shape coefficient of structure
Annex H Equivalent wind load for cross-wind and torsional vibration
Annex J Acceleration of along-wind and cross-wind vibration for high-rise buildings
Annex K Judging method of terrain roughness category
Annex L Wind tunnel test guidelines
Annex M Wind vibration coefficient of unilateral independence cantilevered roof
Explanation of wording in this code
List of quoted codes
