Some standard content:
National Standard of the People's Republic of China
Uniform Standard for Design of Building Structures
GBJ68—84
(Trial Implementation)
Main Compiler: China Academy of Building ResearchApproving Department: State Planning Commission of the People's Republic of ChinaTrial Implementation Date: January 1, 1985
GBJ68--84
Notice on Issuing the "Uniform Standard for Design of Building Structures" Planning and Standardization [198471113]
According to the requirements of the former State Construction Commission (79) Jianfashezi No. 67, the "Uniform Standard for Design of Building Structures" jointly compiled by the China Academy of Building Research, relevant ministries of the State Council and relevant design, scientific research and colleges and universities under the provinces, autonomous regions and municipalities directly under the Central Government has been completed. After review by relevant departments, the "Uniform Standard for Design of Building Structures" GBJ 68—84 is now approved as a national standard for trial implementation from January 1, 1985. The "Uniform Standard for Building Structure Design" is a criterion that must be followed when formulating or revising relevant building structure standards and specifications. Other engineering structure standards and specifications should also try to comply with the relevant principles stipulated in this standard.
For technical matters related to this standard, please contact the China Academy of Building Research directly. State Planning Commission
June 9, 1984
GBJ 68--84
Preparation Instructions
This standard was prepared in accordance with the notice of the former National Capital Construction Commission (79 Jianfa Shezi No. 67), and the China Academy of Building Research, together with the management units of five national standards, including the load specifications for industrial and civil building structures and the design specifications for steel structures, thin-walled steel structures, reinforced concrete structures, masonry structures, and wooden structures, as well as relevant design, scientific research, and colleges and universities, formed the "Uniform Standard for Building Structure Design" Preparation Committee, and was prepared under the specific leadership of the leadership group of the Preparation Committee. In order to prepare this standard, relevant design, scientific research, and colleges and universities across the country, in accordance with unified planning requirements, cooperated with each other, and conducted a large number of surveys, actual measurements, statistical analyses, and theoretical research on the loads on building structures, the performance of various structural materials, and the reliability of various structural components. Research work. This standard absorbs scientific research results at home and abroad, summarizes engineering practice experience, and refers to relevant international standards. After soliciting opinions from relevant units across the country, it was reviewed and finalized at a special meeting. This standard consists of six chapters and one appendix.
The definition of internal reliability and the safety level of building structures, with the main contents including structural
The main contents include the structural limit state design principles based on the theory of structural
rate, the role of the structure, the determination of the representative value of the load, the determination of the representative value of the material properties and geometric parameters, the limit state design expression of the structural components, the quality control of materials and components, etc. If any unit finds that there is a need for modification and supplementation, please send your opinions and relevant information to our institute in time for further revision in the future.
China Academy of Building Research
June 1984
GBJ 68--84
Design reference period of a structure,
Calculated value of probability of failure of a structural member;
Reliability index of a structural member;
Action on a structure;
Action effect of a structure or a structural member;
Basic symbols
Average value of action effect of a structure or a structural member; Standard deviation of action effect of a structure or a structural member, Standard value of permanent load (dead load); Standard value of variable load (live load); Resistance of a structure or a structural member;
Average value of resistance of a structure or a structural member; Standard deviation of resistance of a structure or a structural member; Material properties,
Material Average value of performance;
Standard deviation of material performance;
Standard value of material performance;
Geometric parameters of structure or structural member;
Standard value of geometric parameters of structure or structural member; 4. —Load combination value coefficient;
Quasi-permanent value coefficient of load;
Permanent load effect coefficient;
Variable load effect coefficient;
Partial factor of action on structure;
Partial factor of permanent load;
Partial factor of resistance of structural member;
Partial factor of variable load;
Partial factor of material performance;
Structural importance coefficient.
GBJ 68—84
Chapter 1 General Provisions
Article 1.0.1 This standard is formulated to reasonably unify the basic principles of building structure design of various materials, so that the building structure design meets the requirements of advanced technology, economic rationality, safety and applicability, and quality assurance. Article 1.0.2 This standard is the criterion to be followed in formulating the load specifications for industrial and civil building structures, the design specifications for steel structures, thin-walled steel structures, pry concrete structures, flip structures, and wooden structures, as well as the design specifications for foundations and building earthquake resistance. The above specifications should formulate corresponding specific provisions in accordance with the requirements of this standard. When formulating other civil engineering structure design specifications, the principles specified in this standard may be referred to. This standard applies to the entire structure of a building (including general structures), as well as the components and foundations that make up the structure. It applies to the use stage of the structure, as well as the construction stage such as the manufacture, transportation and installation of structural components. Article 1.0.3 The building structure must meet the following functional requirements: 1. It can withstand various effects that may occur during normal construction and normal use; 2. It has good working performance during normal use; 3. It has sufficient durability under normal maintenance; 4. It can still maintain the necessary overall stability when and after accidental events occur. Note: The durability and fire resistance of the building structure shall comply with the provisions of relevant specifications. Article 1.0.4 The probability that the structure completes the predetermined function within the specified time and under the specified conditions is called the structural reliability. The structural reliability shall be analyzed and determined using the limit state design method based on probability theory. The design reference period T used to calculate the structural reliability can be 50 years.
Article 1.0.5 When designing a building structure, different safety levels should be adopted according to the severity of the possible consequences of structural damage (endangering human life, causing economic losses, and generating social impacts, etc.). The classification of building structure safety levels shall comply with the requirements of Table 1.0.5. Article 1.0.6 The safety level of various structural components in a building should be the same as the safety level of the entire structure. The safety level of some structural components can be adjusted, but it shall not be lower than level three. Article 1.0.7 In order to ensure that the building structure has the specified reliability, in addition to the necessary design calculations, corresponding control shall be carried out on material properties, construction quality, use and maintenance. The relevant building structure construction and acceptance specifications and other standards and specifications shall formulate corresponding regulations in accordance with the requirements of this standard. Table 1.0.5 Safety level of building structure
Safety level
Consequences of damage
Very serious
Not serious
Note: ①For special buildings, their safety level can be determined separately according to specific circumstances; Building type
Important industrial and civil buildings
General industrial and civil buildings
Secondary buildings
②When designed according to earthquake resistance requirements, the safety level of the building structure shall comply with the provisions of the "Industrial and Civil Building Seismic Design Code". Chapter 2 Limit State Design Principles
Article 2.0.1 The entire structure or part of the structure cannot meet a certain functional requirement specified in the design when it exceeds a certain state. This specific state is called the limit state of the function. For various limit states of the structure, clear signs and limits should be specified. Article 2.0.2 The limit state can be divided into the following two categories: 1. The bearing capacity limit state. This limit state corresponds to the deformation of the structure or structural member reaching the maximum bearing capacity or being unsuitable for continued bearing.
GBJ 68--84
When a structure or structural member has one of the following states, it is considered to have exceeded the bearing capacity limit state: 1. The entire structure or part of the structure loses balance as a rigid body (such as overturning, etc.), 2. The structural member or connection is destroyed due to the material strength being exceeded (including fatigue damage), or is unsuitable for continued bearing due to excessive plastic deformation:
3. The structure is transformed into a mobile system,
4. The structure or structural member loses stability (such as compression buckling, etc.). 2. Normal use limit state. This limit state corresponds to a certain specified limit value of normal use or durability of the structure or structural member.
When a structure or structural member has one of the following conditions, it is considered to have exceeded the normal use limit state: 1. Deformation that affects normal use or appearance; 2. Local damage (including cracks) that affects normal use or durability: 3. Vibration that affects normal usebzxZ.net
4. Other specific conditions that affect normal use. Section 2.0.3. When designing building structures, various relevant limit states should be considered. For the limit state under consideration, the most unfavorable combination of the corresponding structural action effects should be determined.
For the ultimate state of bearing capacity, the basic combination of action effects should be considered, and the accidental combination of action effects should be considered when necessary. For the limit state of normal use, the combination of short-term effects and long-term effects should be considered separately according to different design purposes. Article 2.0.4 When considering accidental events, the main load-bearing structure can be designed according to the ultimate state of bearing capacity using one of the following principles:
1. Design or take protective measures according to the accidental combination of action effects so that the main load-bearing structure will not lose its bearing capacity due to accidental events;
2. The main load-bearing structure is allowed to be partially destroyed due to accidental events, but its remaining part still has an appropriate reliability that does not cause continuous lateral collapse for a period of time.
Article 2.0.5 The limit state of the structure shall be described by the following limit state equation: g(Xi,X2,*,X) = 0
Structural function;
X,(i-1,2,.….n)
Basic variables refer to various actions on the structure and material properties, geometric parameters, etc. When conducting structural reliability analysis, action effects and structural resistance can also be used as comprehensive basic variables. The basic variables in the limit state equation should be considered as random variables. Article 2.0.6 The design of the structure according to the limit state shall meet the following requirements: g(X1,X2.,X.) 0
When there are only two basic variables, action effects and structural resistance, the design of the structure according to the limit state shall meet the following requirements: g(S,R) = RS≥0
Where S is the action effect of the structure;
R is the resistance of the structure.
(2. 0. 6-1)
(2. 0. 6-2 )
Article 2.0.7 The reliability of structural components should be measured by reliability index. The reliability index of structural components should be calculated based on the mean value, standard deviation and probability distribution type of basic variables. When there are only two basic variables, action effect and structural resistance, and both are normally distributed, the reliability index of structural components can be calculated according to the following formula:
β = R - Ms
Where β-—reliability index of structural components; (2. 0. 7-1)
GBJ 68--84
Hs, as-—mean value and standard deviation of action effect of structural components; PROR
—mean value and standard deviation of resistance of structural components. The probability that a structural component cannot complete its intended function is called failure probability. The reliability index of a structural member has the following relationship with the probability of failure: (— β)
wherein —the calculated value of the probability of failure of the structural member; Φ (·) —the standard normal distribution function. The probability of a structural member completing its intended function has the following relationship with the probability of failure: p=1—ps
wherein, —the reliability of the structural member. (2.0.7-2)
(2.0.7-3)
When the basic variables are not normally distributed, the reliability index of the structural member shall be calculated by substituting the average value and standard deviation of the normal distribution of the effect and resistance of the structural member into formula (2.0.7-1). Article 2.0.8 The reliability index used in the design of structural members can be determined based on the reliability analysis of the building structure with normal design and construction, and taking into account factors such as use experience and economy.
For the ultimate limit state of bearing capacity, the reliability index of the structural member shall be determined according to Table 2.0.8 based on the damage type and safety level of the structural member. For the positive service limit state, the reliability index of the structural member shall be determined according to the characteristics of the structural member and engineering experience. Article 2.0.9 Structural analysis shall be based on the requirements of different limit states, according to the response of materials and structures to the action, and select the analysis method that can reflect the structural performance.
When analyzing the reliability of structural members, the inaccuracy of the action effect and the design calculation model of the structural member resistance should introduce additional basic variables into the limit state equation. The relevant statistical parameters and distribution types can be determined by comparing the calculation results of the design calculation model with the calculation results of the accurate model or the test results, through statistical analysis or based on engineering experience. Structural member bearing capacity limit state
Reliability index β value used in design
Safety level
Failure type
Ductile failure
Brittle failure
Note: ① Ductile failure refers to the obvious deformation or other signs of structural members before failure; brittle failure refers to the absence of obvious deformation or other signs of structural members before failure.
②When there is sufficient basis, the β value adopted in the structural design specifications for various materials may be adjusted to the specified value of this attenuation by no more than ±0.25. ③When subjected to accidental actions, the reliability index of structural components shall comply with the provisions of special specifications. When there are special requirements, the reliability index of structural components may not be restricted by this table.
Chapter 3 Structural Actions
Article 3.0.1 Concentrated or distributed loads imposed on the structure, as well as the causes of imposed or restrained deformation of the structure, are all called structural actions.
The causes of imposed or restrained deformation of the structure refer to thunder, foundation settlement, temperature changes, welding and other actions. If the various structural actions can be regarded as independent of each other in time or space, each action can be considered as a separate action on the structure.
Article 3.0.2 Structural actions F can be classified according to the following principles: 1. Classification by variation over time
1. 1. Permanent action: Its value does not change with time during the design reference period, or its change can be ignored compared with the average value. For example, structural deadweight, soil pressure, prestressing, foundation settlement, welding, etc. 2. Variable action: Its value changes with time during the design reference period, and its change cannot be ignored compared with the average value. For example, installation load, floor live load, wind load, snow load, crane load, temperature change, earthquake, etc. 3. Accidental action: It may not appear during the design reference period, but it appears with a large value and a short duration. For example, earthquake, explosion, impact, etc.
2. Classification according to variation with spatial position
GBJ 68-84
1. Fixed action: It has a fixed distribution in the spatial position of the structure. For example, fixed equipment load on the floor of industrial and civil buildings, deadweight of structural components, etc.
2. Movable action: It can be arbitrarily distributed within a certain range in the spatial position of the structure. For example, personnel loads and crane loads on industrial and civil buildings.
III. Classification by structural response
1. Static action: does not cause acceleration in the structure or structural components, or the acceleration caused can be ignored. For example, the deadweight of the structure, live loads on the floors of residential and office buildings, etc. 2. Dynamic action: causes the structure or structural components to produce non-negligible acceleration. For example, earthquakes, crane loads, equipment vibrations, wind loads on high-rise structures, etc.
Article 3.0.3 The loads applied to the structure should be described by a random process probability model. The sample functions of the random processes of live loads on the floors of residential and office buildings, as well as wind and snow loads, can be modeled as rectangular blankets of equal time periods. Article 3.0.4 When the sample function of the load bag random process adopts the rectangular wave function of equal time period, the probability distribution function of the maximum load bag in the design reference period shall be determined according to the following formula: Fo() = (1 -p[1 —Fe(α)J)
wherein Fa,a) is the probability distribution function of the maximum load Qt in the design reference period; Fα() is the probability distribution function of the load Q at any time point, β is the probability of the load occurring in each time period; r is the number of time periods in the design reference period.
In general, formula (3.0.4-1) can be replaced by the following approximate formula: Fα,(α)= [F(α)J\
wherein m is the average number of occurrences of the load in the design reference period, m pr. (3.0.4-1)
( 3.0.4-2 )
Article 3.0.5 Various statistical parameters of loads and probability distribution functions of loads at any time point shall be determined based on observation and test data using parameter estimation and probability distribution hypothesis testing methods. The significance level of the test may be 0.05. When observation and test data are insufficient, various statistical parameters of loads may be determined through analysis and judgment in combination with engineering experience. Article 3.0.6 When designing a structure, different representative values of loads shall be adopted according to the design requirements of various limit states. Permanent loads shall adopt standard values as representative values, and variable loads shall adopt standard values, combined values or quasi-permanent values as representative values. When there are special requirements in the design, other representative values of loads may be specified in the relevant specifications. Article 3.0.Article 7. The standard value of load is the basic representative value of load used in structural design. The standard value G of the self-weight of the structure can be calculated according to the design size and the standard bulk density of the material. For some materials or structural components with large weight variation (such as insulation materials made on site, concrete thin-walled components, etc.), the standard value of the self-weight should be determined based on the unfavorable state of the structure and a certain quantile of its probability distribution through structural reliability analysis. The standard value Q of the variable load should be determined based on a certain quantile of the probability distribution of the maximum load in the design reference period of the load. Note: When observation and test data are insufficient, the standard value of load can be determined by combining engineering experience and analysis and judgment. Article 3.0.8 of the set of load combination values Q is the representative value of the variable load used when the ultimate bearing capacity state is designed according to the basic combination and the normal use limit state is designed according to the short-term effect combination when the structure is subjected to two or more variable loads. The load combination value should be determined based on the avoidance of two or more variable loads in the design reference period and the probability distribution of each large load effect of the combination, and considering the consistency of the reliability index of the structural component when different load effects are combined. Article 3.0.9 The quasi-permanent value of load is the representative value of variable load used in the design of long-term effect combination for the normal use limit state.
The quasi-permanent value of load shall be determined based on the total duration T of the load reaching and exceeding the value during the design reference period. The ratio of the design reference period T is - a given value.
Article 3.0.10 The representative values of various accidental actions used in the design of the ultimate limit state of bearing capacity can be determined through comprehensive analysis and judgment based on observation and test data or engineering experience. 971
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Chapter 4 Material Properties and Geometric Parameters
Article 4.0.1 Material properties refer to the physical and mechanical properties of materials such as strength and deformation modulus. Material properties shall be determined by tests based on relevant test methods and standards.
Material properties should be described by random variable probability models. Various statistical parameters and probability distribution functions of material properties shall be determined based on test data and using parameter estimation and probability distribution hypothesis testing methods. The significance level of the test can be 0.05. Article 4.0.2 When using the test results of standard specimens to determine the actual material properties in the structure, the differences between the actual structure and the standard specimens, and between the actual working conditions and the standard test conditions should also be considered. The relationship between the material properties in the structure and the material properties of the standard specimens should be reflected through conversion factors or functions based on the corresponding comparative test results, or determined based on engineering experience. The uncertainty of material properties in the structure consists of the uncertainty of the material properties of the standard specimens and the uncertainty of the conversion factors or functions. Article 4.0.3 The standard value f of the material property is the basic representative value of the material property used in the structural design. The standard value of the material property should be determined based on a certain quantile of the probability distribution of the material properties that meet the specified quality. Article 4.0.4 The probability distribution of material strength should adopt normal distribution or lognormal distribution. The standard value of material strength can be determined by taking the 0.05 quantile of its probability distribution. The standard value of physical properties such as the elastic modulus and Poisson's ratio of the material can be determined by taking the 0.5 quantile of its probability distribution. Note: When test data is insufficient, the standard value of material performance may adopt the specified value of the relevant standard, or it may be determined through analysis and judgment in combination with engineering experience. Article 4.0.5 The geometric parameter α of the structure or structural member should be described by a random variable probability model. Various statistical parameters and probability distribution functions of geometric parameters shall be determined based on the test data of the geometric dimensions of the structure or structural member under normal production conditions, using parameter estimation and probability distribution hypothesis testing methods. When test data is insufficient, the statistical parameters of geometric parameters may be determined through analysis and judgment based on the tolerances specified in the relevant standards. The standard value α of the geometric parameter may adopt the design value. Chapter 5 Limit State Design Expression
Article 5.0.1 The limit state design expression of structural members shall be expressed in accordance with the design requirements of various limit states, using relevant load representative values, material performance standard values, geometric parameter standard values, and various partial factors. The action partial factor Yr (including the load partial factor YG,) and the structural member resistance partial factor (or material performance partial factor Y) shall be determined by calculation and analysis based on the statistical parameters and probability distribution type of the basic variables of the structural function function and the reliability index of the structural member specified in Article 2.0.8, and taking into account engineering experience. The structural importance factor. It shall be determined according to the safety level of the structural member. Article 5.0.2 For the ultimate limit state of bearing capacity, the structural member shall be designed using the basic combination and accidental combination of load effects in accordance with the requirements of Article 2.0.3.
, basic combination
For the basic combination, the following limit state design expression should be adopted: ZraCadeQu)≤R(Yr fu,dy)
Y,(YcCeG + YQiCQiQik +
( 5. 0.2-1 )
. ...Structural importance factor, for structural members with safety levels of one, two and three, it can be taken as 1.1, 1.0 and 0.9 respectively;——permanent load partial factor, in general, 1.2 can be used; YQl~Q-the-th and other i-th variable load partial factors, in general, 1.4 can be used; Gk——standard value of permanent load;
standard value of the first variable load, the effect of this variable load standard value is greater than the effect of any other variable load standard value; Gk---
GBJ 68—84
Qik—standardized value of other i-th variable loads; Cc, CQ1, CQ—load effect coefficients of permanent loads, the first variable load and other i-th variable loads; e—combination value coefficient of i-th variable load. When wind load is combined with other variable loads, α.6 can be used.—resistance function of structural components;
R(·)-
YR—resistance partial coefficient of structural components. Its value should comply with the provisions of structural design specifications for various materials; fi—standard value of material properties;
standard value of geometric parameters. When the variability of geometric parameters has a significant impact on structural performance, an additional value △ can be added or subtracted. Consider its adverse effects.
For general bent and frame structures, the following simplified limit state design expression can be used: Y.(YeCGG +
YaCaQi ≤ R(YR,fe,ak,)(n ≥ 2)(5.0. 2-2 )
Wherein, 虫 is the load combination factor used in the simplified design expression. When wind load is combined with other variable loads, 0.85 can be used. Note: The load effects should be combined according to the variable loads that the structure may bear simultaneously, and the most unfavorable combination should be taken for design. The specific combination rules of various variable loads shall comply with the provisions of the "Code for Loads of Industrial and Civil Building Structures". 2. Accidental Combinations
For accidental combinations, the limit state design expression should be determined according to the following principles: the representative value of the accidental action shall not be multiplied by the partial coefficient; the variable loads that appear simultaneously with the accidental action may be based on According to observation data and engineering experience, appropriate representative values shall be adopted. Specific design expressions and various coefficient values shall comply with the provisions of special specifications. Article 5.0.3 When the permanent load effect is beneficial to the bearing capacity of structural components, the permanent load partial coefficient % in formulas (5.0.2-1) and (5.0.2-2) should be 1.0.
Article 5.0.4 For the normal use limit state. Structural components shall be designed according to the requirements of Article 2.0.3 using the short-term effect combination and long-term effect combination of loads, and the calculated values of deformation, cracks, etc. shall not exceed the corresponding specified limits. 1. Short-term effect combination
CcG + CaQik +
Where Q is the combination value of the th variable load. 2. Long-term effect combination
Where Qi is the quasi-permanent value of the th variable load. Zp.CaQk
Chapter 6 Quality Control of Materials and Components
Article 6.0.1 The quality of materials and components can be expressed by one or more quality characteristics. In the structural design and construction specifications of various materials, clear requirements should be put forward for the mechanical properties, geometric parameters and other quality characteristics of materials and components. The qualified quality level of materials and components should be determined according to the structural component reliability indicators specified in the structural design specifications of various materials. Article 6.0.2 Materials should be classified into grades according to different quality levels based on statistical data, and the grade classification should not be too dense. Different material performance standard values should be used in the design of materials of different grades. Article 6.0.Article 3 The quality control of materials and components shall include the following three types of control: 1. Preliminary control: For artificial materials and components, reasonable raw material composition and process parameters shall be determined according to the qualified quality level of materials and components during the trial production stage, and statistical parameters of material and component performance shall be provided for production control and qualified control. 2. Production control: In the formal production stage, the performance of materials and components shall be regularly inspected according to the prescribed control standards, deviations shall be corrected in time, and the stability of quality during the production process shall be maintained. 973
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3. Qualified control (acceptance): Before delivery and use, materials and components shall be qualified and accepted according to the prescribed quality acceptance standards to ensure that their quality meets the requirements.
Article 6.0.4 Qualified control can be carried out by sampling inspection method. Specific quality acceptance standards shall be formulated for various materials and components according to their characteristics. Among them, the acceptance batch, sampling method and quantity, acceptance function and acceptance limit shall be clearly specified.
Quality acceptance standards should be formulated on the basis of statistical theory. Article 6.0.5 For materials and components with poor production continuity or large differences in statistical parameters of quality characteristics between batches, the user's risk rate must be controlled when formulating quality acceptance standards. The limit quality level used in calculating the user's risk rate can be determined by reducing the reliability index of structural components specified in the structural design specifications for various types of materials by 0.25. When there is sufficient basis, the aggregate index used to determine the limit quality level can be appropriately adjusted.
Only for materials and components produced continuously, when the product quality is stable, quality acceptance standards can be formulated under the condition of controlling the production risk rate.
Article 6.0.6 When a batch of materials or components is judged to be unqualified after sampling inspection, the batch of products should be reviewed or its quality grade should be re-determined according to the relevant quality acceptance standards, or other measures should be taken to deal with it. 974
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Appendix Explanation of the use of this standard
1. In order to facilitate the distinction in the implementation of the provisions of this standard, the wording of the degree of strictness is explained as follows: 1. Words that express strictness and must be done: positive words use "must" and negative words use "strictly prohibited".
2. Words that indicate strictness and should be done in normal circumstances; positive words use "should";
negative words use "should not" or "must not". 3. Words that indicate that a slight choice is allowed and should be done first when conditions permit: positive words use "should" or "may";
negative words use "should not".
2. When the article specifies that other relevant standards and specifications should be followed, the wording should be "should be followed" or "should comply with regulations". When it is not necessary to follow the specified standards, specifications or other regulations, the wording should be "may refer to...". Annex I Representative values of statistical characteristics of loads and their effect combinations This annex mainly explains the loads used in this standard. The load probability model, load representative value and load effect combination rules are introduced, and the statistical parameters and probability distribution types of various loads required for analyzing the reliability of structures by probability method are given. The discussion in this article is only applicable to the various loads applied to the structure, and does not involve the causes of external deformation and beam deformation of the structure. Since the load and load effect are generally linearly related, that is, the ratio of the two is a constant, when conducting structural reliability analysis, the load statistical characteristics described in this annex can be applied to the load effect accordingly. 1. Probabilistic model of loads
The loads involved in the design of building structures, except for permanent loads, are generally variable loads that change with time, so the random process probability model is adopted. It is more practical to describe it. In this standard, several common loads are uniformly modeled as a stationary binomial random process (Q(t), E((O, T), that is, it is assumed that: (1) the design reference period T of the building structure is 50 years; (2) the length of the period in which the load is continuously applied to the structure is, and the design reference period T can be divided into r equal periods, that is, rT/tt
(3) the probability of the load appearing in each period is p, and the probability of not appearing is 9-1-force; (4) in each period, when the load appears, its amplitude is a non-negative random variable, and its probability distribution function Fa(r) is the same in different periods. This probability distribution is called arbitrary point time Load probability distribution; (5) The amplitude random variables in different time periods are independent of each other, and are also independent of whether the load occurs in the time period. The above assumptions actually model the sample function of the load random process as a rectangular wave function of equal time periods. For this model, each load must be given t, force and F. ) three statistical elements.
Since in the first-order second-moment structural feasibility analysis method that considers the probability distribution type of basic variables adopted in this standard, various basic variables are considered as random variables, so the above load random process Q(t) must be converted into the maximum load random variable g(t) of the design reference period
Figure 1-1 Sample function of load1. Words that indicate strictness and should be done in normal circumstances: positive words use "should"; negative words use "should not" or "must not". 2. Words that indicate that a slight choice is allowed and should be done first when conditions permit: positive words use "should" or "may"; negative words use "should not". 3. Words that indicate that a slight choice is allowed and should be done first when conditions permit: positive words use "should" or "may"; negative words use "should not". 2. When the article specifies that other relevant standards and specifications should be followed, the wording should be "should be followed" or "should comply with regulations". When it is not necessary to follow the specified standards, specifications or other regulations, the wording should be "may refer to...". Appendix 1 Representative values of statistical characteristics of loads and their effect combinations This appendix mainly explains the load probability model, The representative values of loads and the rules for combining load effects are given, and the statistical parameters and probability distribution types of various loads required for analyzing the reliability of structures by probability method are given. The discussion in this article is only applicable to the various loads applied to the structure, and does not involve the causes of external deformation and beam deformation of the structure. Since the load and load effect are generally linearly related, that is, the ratio of the two is a constant, when conducting structural reliability analysis, the statistical characteristics of the loads described in this annex can be applied to the load effect accordingly. 1. Probabilistic model of loads
The loads involved in the design of building structures, except for permanent loads, are generally variable loads that change with time, so a random process probability model is used to describe the ratio. More practical. In this standard, several common loads are uniformly modeled as a stationary binomial random process (Q(t), E((O, T), that is, it is assumed that: (1) the design reference period T of the building structure is 50 years; (2) the length of the period in which the load is continuously applied to the structure is, and the design reference period T can be divided into r equal periods, that is, rT/tt
(3) the probability of the load appearing in each period is p, and the probability of not appearing is 9-1-force; (4) in each period, when the load appears, its amplitude is a non-negative random variable, and its probability distribution function Fa(r) is the same in different periods. This probability distribution is called the load at any point Probability distribution; (5) The amplitude random variables in different time periods are independent of each other, and are also independent of whether the load occurs in the time period. The above assumptions actually model the sample function of the load random process as a rectangular wave function of equal time periods. For this model, each load must be given t, force and F. ) three statistical elements.
Since in the first-order second-moment structural feasibility analysis method that considers the probability distribution type of basic variables adopted in this standard, various basic variables are considered as random variables, so the above load random process Q(t) must be converted into the maximum load random variable g(t) of the design reference period
Figure 1-1 Sample function of load1. Words that indicate strictness and should be done in normal circumstances: positive words use "should"; negative words use "should not" or "must not". 2. Words that indicate that a slight choice is allowed and should be done first when conditions permit: positive words use "should" or "may"; negative words use "should not". 3. Words that indicate that a slight choice is allowed and should be done first when conditions permit: positive words use "should" or "may"; negative words use "should not". 2. When the article specifies that other relevant standards and specifications should be followed, the wording should be "should be followed" or "should comply with regulations". When it is not necessary to follow the specified standards, specifications or other regulations, the wording should be "may refer to...". Appendix 1 Representative values of statistical characteristics of loads and their effect combinations This appendix mainly explains the load probability model, The representative values of loads and the rules for combining load effects are given, and the statistical parameters and probability distribution types of various loads required for analyzing the reliability of structures by probability method are given. The discussion in this article is only applicable to the various loads applied to the structure, and does not involve the causes of external deformation and beam deformation of the structure. Since the load and load effect are generally linearly related, that is, the ratio of the two is a constant, when conducting structural reliability analysis, the statistical characteristics of the loads described in this annex can be applied to the load effect accordingly. 1. Probabilistic model of loads
The loads involved in the design of building structures, except for permanent loads, are generally variable loads that change with time, so a random process probability model is used to describe the ratio. More practical. In this standard, several common loads are uniformly modeled as a stationary binomial random process (Q(t), E((O, T), that is, it is assumed that: (1) the design reference period T of the building structure is 50 years; (2) the length of the period in which the load is continuously applied to the structure is, and the design reference period T can be divided into r equal periods, that is, rT/tt
(3) the probability of the load appearing in each period is p, and the probability of not appearing is 9-1-force; (4) in each period, when the load appears, its amplitude is a non-negative random variable, and its probability distribution function Fa(r) is the same in different periods. This probability distribution is called the load at any point Probability distribution; (5) The amplitude random variables in different time periods are independent of each other, and are also independent of whether the load occurs in the time period. The above assumptions actually model the sample function of the load random process as a rectangular wave function of equal time periods. For this model, each load must be given t, force and F. ) three statistical elements.
Since in the first-order second-moment structural feasibility analysis method that considers the probability distribution type of basic variables adopted in this standard, various basic variables are considered as random variables, so the above load random process Q(t) must be converted into the maximum load random variable g(t) of the design reference period
Figure 1-1 Sample function of load
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