GB 50216: Evolution and historical versions
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Unified design standard for reliability of railway engineering structures
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GB 50216-2019
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Unified design standard for reliability of railway engineering structures
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Basic data | Standard ID | GB 50216-2019 (GB50216-2019) | | Description (Translated English) | Unified design standard for reliability of railway engineering structures | | Sector / Industry | National Standard | | Classification of Chinese Standard | P65 | | Classification of International Standard | 93.100 | | Word Count Estimation | 133,180 | | Date of Issue | 2019 | | Date of Implementation | 2020-06-01 | | Issuing agency(ies) | Ministry of Housing and Urban-Rural Development of the People's Republic of China; State Administration for Market Regulation | GB 50216-2019: Unified design standard for reliability of railway engineering structures---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
1 General
1.0.1 This standard is formulated to unify the basic principles, basic requirements and basic methods of reliability design of railway engineering structures, so that railway engineering meets the requirements of sustainable development, and achieves safety, reliability, advanced technology, reasonable economy, and quality assurance.
1.0.2 This standard applies to the design of engineering structures and components such as railway bridges and culverts, tunnels, roadbeds, and tracks, as well as the reliability assessment of existing structures.
1.0.3 The limit state design method based on probability theory and expressed by sub-item coefficients should be used in the design of railway engineering structures; when statistical data is lacking, other design methods can be used for design based on reliable engineering experience or necessary experimental research.
1.0.4 When formulating relevant standards for reliability design of railway engineering structures, the provisions of this standard shall be complied with.
1.0.5 The investigation, design, construction, use and maintenance of railway engineering structures shall be subject to effective quality management and control, so that the structures meet the specified reliability requirements.
1.0.6 The reliability design of railway engineering structures shall not only meet the requirements of this standard, but also meet the provisions of the current relevant national standards.
2 Terms and symbols
2.1 Terminology
2.1.1 Reliability reliability
The ability of a structure to complete a predetermined function within a specified time and under specified conditions.
2.1.2 degree of reliability
The probability that the structure will complete the intended function within the specified time and under the specified conditions.
2.1.3 probability of failure probability of failure
The probability that a structure cannot complete its intended function within a specified time and under specified conditions.
2.1.4 reliability index
The numerical index to measure the structural reliability, the relationship between the reliability index β and the failure probability Pf is β=—Φ-1(Pf), where Φ-1(·) is the inverse function of the standard normal distribution function.
2.1.5 design working life
Under normal use and maintenance conditions, the design-specified structure or component can be used for the intended purpose without major repairs.
2.1.6 design reference period design reference period
A time parameter chosen to determine the value of a variable action, etc.
2.1.7 assessed working life
The service life of the existing structure estimated by the reliability assessment under specified conditions.
2.1.8 Safety class safety class
Design grades with different reliability setting levels divided according to the severity of the consequences of engineering structure damage.
2.1.9 Design situation design situation
A group of design conditions representing the actual situation in a certain period of time, and the design should be such that the structure does not exceed the relevant limit state under this group of conditions.
2.1.10 limit state limit state
A structure or component cannot meet a certain functional requirement specified in the design beyond a specific state, and this specific state is the limit state of the function.
2.1.11 limit state equation limit state equation
When the structure or component is in the limit state, the relational expressions of the relevant basic variables.
2.1.12 Ultimate limit state of carrying capacity
A state in which a structure or component has reached its maximum load-bearing capacity or has undergone deformation that is not suitable for continued load-bearing.
2.1.13 Normal use limit state serviceability limit state
A state in which a structure or member has reached a specified limit of normal service or durability.
2.1.14 Reversible normal serviceability limit state reversible serviceability limit state
When the action that exceeds the normal use requirements is removed, the excess state produced by the action can be restored to the limit state of normal use.
2.1.15 Irreversible normal serviceability limit state irreversible serviceability limit state
When the action that exceeds the normal use requirements is removed, the beyond state produced by the action cannot be restored to the limit state of normal use.
2.1.16 fatigue limit state fatigue limit state
The limit state in which the structure or component fails due to repeated loading and is not suitable for continued bearing.
2.1.17 importance factor of structure
Additional adjustment factors for action effects as specified by the safety class of the structure.
2.1.18 basic variable basic variable
A defined set of variables representing physical quantities used to characterize actions and environmental influences, properties of materials and soils, and geometric parameters.
2.1.19 Function function performance function
A function with respect to elementary variables that characterizes a structural function.
2.1.20 probability distribution probability distribution
The statistical law of the value of a random variable is generally represented by a probability density function or a probability distribution function.
2.1.21 Statistical parameter
In the probability distribution, it is used to represent the numerical characteristics of the average level and dispersion degree of the value of the random variable.
2.1.22 Quantile value fractile
The value corresponding to a certain probability of the probability distribution function of a random variable.
2.1.23 characteristic value
The value under a certain guarantee rate or cross-threshold rate determined by statistical methods.
2.1.24 nominal value nominal value
Value determined by non-statistical methods.
2.1.25 calibration method calibration method
Through the inverse analysis of the existing structure or component safety reserve, the method of determining the target reliable index adopted by the design.
2.1.26 action
Concentrated or distributed forces exerted on a structure (direct action, also called load) and causes of imposed or constrained deformation of the structure (indirect action).
2.1.27 geotechnical action
The effect of surrounding rock, foundation, slope, groundwater or surface water on the structure.
2.1.28 effect of action
The response of a structure or member to an action.
2.1.29 characteristic value of an action
The main representative value of the action can be determined according to the statistics of the observed data, the natural limit of the action or engineering experience.
2.1.30 combination value of a variable action
The action value that makes the exceedance probability of the combined action effect converge with the exceedance probability of the standard value action effect when the action appears alone; or the action value that makes the structure have a specified reliable index after combination. It can be expressed by the reduction of the combined value coefficient (ψc≤1) to the standard value of the action.
2.1.31 frequent value of a variable action
The action value whose ratio of the total time exceeded in the design base period to the design base period is small; or the action value where the exceeded frequency is limited to the specified frequency. It can be expressed by the reduction of the function standard value by the frequent occurrence value coefficient (ψf≤1).
2.1.32 quasi-permanent value of a variable action quasi-permanent value of a variable action
The effect value with a larger ratio of the total time exceeded in the design base period to the design base period. It can be expressed by the reduction of the quasi-permanent value coefficient (ψq≤1) to the standard value of the action.
2.1.33 representative value of an action
The action value used in the limit state design, which can be the standard value, combined value, frequent value or quasi-permanent value of the action.
2.1.34 Design value of an action
The product of the representative value of the action and the partial coefficient of the action.
2.1.35 Action combination (load combination) combination of actions (load combination)
A collection of several different actions (effects) that may occur simultaneously when designing a structure or component.
2.1.36 leading variable action leading variable action
In the same action combination, the variable action that plays a controlling role in the most unfavorable case of the action-effect design value.
2.1.37 standard combination characteristic combination
In the design of the limit state of normal service, the combination of the standard value of the permanent action, the standard value of the dominant variable action and (or) the combined value of the non-dominant variable action is adopted.
2.1.38 frequent combination
In the design of the limit state of normal service, a combination of the standard value of the permanent action, the frequent value of the dominant variable action and (or) the quasi-permanent value of the non-dominant variable action is used.
2.1.39 quasi-permanent combination
In the design of the limit state of normal service, the combination of the standard value of permanent action and the quasi-permanent value of variable action is adopted.
2.1.40 Environmental influence
Various mechanical, physical, chemical or biological adverse effects of the environment on the structure.
2.1.41 Resistance
The ability of a structure or component to withstand the effects of an action.
2.1.42 The standard value of material performance characteristic value of a material property
A quantile of the probability distribution of a material property of specified quality or a nominal value of a material property.
2.1.43 Design value of a material property-erty
The value obtained by dividing the standard value of material properties by the partial coefficient of material properties.
2.1.44 The standard value of a geometric parameter characteristic value of a geometry-rical parameter
The nominal value of the geometric parameter specified in the design or a certain quantile value of the probability distribution of the geometric parameter.
2.1.45 design value of a geometrical pa-rameter
The standard value of a geometry parameter is increased or decreased by an additional amount of a geometry parameter.
2.1.46 limit value constraint value
In the design of structures or components, the constraint values of stress, deformation, etc. as the limit state signs.
2.1.47 fatigue load spectrum fatigue load spectrum
It reflects the relationship between the effect and frequency of materials or connections under the fatigue load of the train under the specified train capacity within the service life of the structural design, which can be expressed in tables or histograms.
2.1.48 equivalent constant amplitude stress range method of equivalent constant amplitude stress range
In the fatigue checking and calculation of structures or components, according to the linear cumulative damage law or other appropriate methods, the method of converting variable-amplitude repetitive stress into constant-amplitude repetitive stress for design.
2.1.49 Cumulative damage method
In the fatigue checking of structures or components, according to the linear damage theory, the cumulative damage degree is used as the design method of the checking content.
2.2 Symbols
2.2.1 Structural reliability.
Pf—calculated value of failure probability of structure or component;
R——resistance of structure or member;
S—the action effect of structure or component;
T—design reference period;
wi - the weight coefficient of the i-th structure;
Xi——the i-th basic variable;
X*i——the quantile value of the basic variable Xi at the quantile probability Φ(βXi);
X*′i——the quantile value derivative of the basic variable Xi at the quantile probability Φ(βXi);
Z - the functional function of the structure or component;
αXi——the sensitivity coefficient of the basic variable Xi;
β—reliable index of structure or component;
βXi—the sub-item reliability index of the basic variable Xi;
σR——Standard deviation of resistance;
σS——the standard deviation of the action effect;
σXi——the standard deviation of the basic variable Xi.
2.2.2 Action and action effect.
F - function;
Fk - standard value of action;
Fr - the representative value of the function;
G - permanent effect;
Gk - the standard value of permanent action;
SGk - the effect of the standard value of permanent action;
Q - variable action;
Qk—standard value of variable action;
Qr——representative value of variable action;
SQk—the effect of variable action standard value;
ψc—coefficient of combined value of variable action;
ψf—frequent value coefficient of variable action;
ψq——quasi-permanent value coefficient of variable action;
ψcQk——combined value of variable action;
ψfQk——Frequency value of variable action;
ψqQk—Quasi-permanent value of variable action.
2.2.3 Material properties and geometric parameters.
a - geometric parameters;
anom - the standard or nominal value of the geometric parameter;
f——structural material performance;
fk—standard value of structural material property f;
δf—coefficient of variation of structural material performance f.
2.2.4 Design formula of structural limit state.
ad——design value of geometric parameter a;
Cd——the corresponding limit value specified by the design for the structure to reach normal use (such as deformation, cracks, etc.);
Fd——the design value of function F;
fd——design value of material property f;
Gd - design value of permanent action G;
Qd——design value of variable action Q;
Rd—design value of structural resistance R;
Sd——the design value of action effect;
AEk—standard value of earthquake action;
βnom - target reliability indicator of the structure;
γ0——structural importance coefficient;
γⅠ—the importance coefficient of earthquake action;
γF—the partial coefficient of action;
γsd—calculation model uncertainty coefficient;
γm—subitem coefficient of material or product performance;
γRd—uncertainty coefficient of resistance model;
γM—subitem coefficient of material or product performance, considering the influence of model uncertainty and (or) geometric parameter deviation;
γL——load adjustment factor considering the design service life of the structure;
γR——sub-item coefficient of resistance;
γG——partial coefficient of permanent action G;
γQ—the sub-item coefficient of variable action Q;
△a——Additional amount of geometric parameter a.
2.2.5 Structural fatigue limit state checking formula.
γfat—subitem coefficient of steel structure fatigue effect;
△σe——equivalent equal-amplitude repetitive stress amplitude standard value of the steel structure checking position (included in the operating dynamic coefficient and centrifugal force);
△σ0——the fatigue design strength of the steel structure checking part;
△faek—Standard value of equal-amplitude fatigue strength of the material (or structural details) of the checking part of the steel structure;
γaf—the fatigue resistance sub-item coefficient of the material (or structural details) of the checking part of the steel structure;
γcek, γpek, γsek—respectively, the sub-item coefficients of the fatigue action of concrete, prestressed steel bars, and steel bars;
γcf, γpf, γsf—respectively, the partial coefficients of fatigue resistance of concrete, prestressed steel bar and steel bar;
σcek, △σpek, △σsek—respectively, the standard value of equivalent fatigue stress of concrete, the standard value of equivalent fatigue stress amplitude of prestressed steel bar, and the standard value of equivalent fatigue stress amplitude of steel bar of the concrete structure checking part (included in the operating dynamic coefficient, centrifugal force);
fcek, △fpek, △fsek—respectively, the standard values of equal-amplitude fatigue strength of concrete, prestressed steel bars, and steel bars in the concrete structure checking position.
3 Basic Regulations
3.1 Basic requirements
3.1.1 The design, construction and maintenance of the railway engineering structure shall make it meet the specified functional requirements with the specified reliability within the design service life.
3.1.2 The railway engineering structure should reach the specified reliability level and meet the following functional requirements.
1 To withstand various actions that may occur during construction and use, that is, to meet the requirements of the limit state of bearing capacity or fatigue limit state;
2 Maintain good performance and have sufficient durability, that is, meet the limit state requirements of normal use;
3 In the event of accidental events such as flood, abnormal impact, train derailment, etc., the structure shall maintain the necessary overall stability, and there shall be no damage consequences that are not commensurate with the cause; in the event of a fire, sufficient bearing capacity shall be maintained within the specified time.
3.1.3 When designing a railway engineering structure, an appropriate calculation model and reasonable basic variable values should be selected, and appropriate measures should be taken according to the following requirements.
1 The possible damage to the structure should be avoided, eliminated or reduced;
2 The structural type that is insensitive to the possible hazard response should be adopted;
3.When a single member or a limited part of a structure is accidentally removed or the structure undergoes acceptable local damage, the structure type that other parts of the structure can still be preserved shall be adopted;
4 It is not suitable to adopt the structural system without warning of damage.
3.1.4 Corresponding reliability management measures should be taken for the investigation and design, construction, use and maintenance of railway engineering structures.
3.2 Safety level and reliability
3.2.1 The design of railway engineering structure shall adopt the safety level specified in Table 3.2.1 according to the severity of possible consequences of structural damage.
Table 3.2.1 Safety grades of railway engineering structures
3.2.2 The safety grades of railway engineering structures shall be classified according to the provisions in Table 3.2.2.
Table 3.2.2 Classification of safety grades for railway engineering structures
Note. For railway engineering structures with special requirements, their design safety level can be determined according to specific conditions.
3.2.3 The safety level of various components of the railway engineering structure should be the same as the safety level of the structure, and the safety level of some components can be adjusted if necessary.
3.2.4 The setting of the reliability level shall be determined according to the safety level, failure mode and economic factors of the structure or component.
3.2.5 When sufficient statistical data are available, the reliability of structures or components should be measured by the reliability index β. The reliability index used in the design of structures or components can be determined based on the reliability analysis of existing structures or components, combined with experience and economic factors.
3.2.6 The failure types of railway engineering structures can be divided into ductile failure and brittle failure, and the reliability of brittle failure should be higher than that of ductile failure.
3.3 Design life, durability and maintenance
3.3.1 When designing a railway engineering structure, the design service life of the structure should be specified.
3.3.2 The design service life of railway engineering structure shall be classified according to 100 years, 60 years and 30 years.
3.3.3 The structural design of railway engineering should consider the environmental impact, adopt corresponding structural materials, design structures, protective measures, construction quality requirements, etc. Meet the requirements of safety and normal use within the period of time.
3.3.4 The influence of the environment on the durability of railway engineering structures can be evaluated by methods such as engineering experience, experimental research, theoretical calculation or comprehensive analysis.
3.3.5 The division of environmental categories and the corresponding design, construction, use and maintenance requirements, etc., shall comply with the current relevant national standards.
4 Principles of limit state design
4.1 Limit state
4.1.1 The railway engineering structure should be designed according to the limit state of bearing capacity and the limit state of normal service. Components subjected to repeated loads should still be checked and calculated according to the fatigue limit state.
4.1.2 When one of the following states occurs in the structure or component, it shall be considered as exceeding the limit state of the bearing capacity.
1 The structure, member or connection exceeds the material strength, or the excessive deformation is not suitable for continuous bearing;
2 The structure or part of the structure loses balance as a rigid body;
3 The structural system becomes a mobile system;
4 Instability of structures or components;
5 The foundation loses its bearing capacity;
6 Other specific conditions affecting the safety of the structure.
4.1.3 When one of the following states occurs in the structure or component, it shall be deemed to have exceeded the limit state of normal service.
1 Deformation affecting normal use;
2 Cracks and partial damages that affect normal use or durability;
3 Vibrations affecting normal use and comfort;
4 Other specific conditions affecting normal use.
4.1.4 When one of the following states occurs under the cumulative damage of repeated loads, the structure or member shall be deemed to have exceeded the fatigue limit state.
1 Fatigue cracks affecting safe use;
2 Deformation affecting safe use.
4.1.5 The structural design of railway engineering should specify the signs or limit values of various limit states.
4.1.6 In the design of railway engineering structures or components, calculations or checking calculations should be carried out for different limit states, and to ensure that the structure is reasonable.
4.1.7 The limit state of railway engineering structure can be expressed by the limit state equation composed of action effect and resistance force.
4.2 Design status
4.2.1 The structural design of railway engineering should consider the following design conditions.
1 The permanent design condition is applicable to the normal condition when the structure is in use, and the relatively long-lasting effects such as permanent action, train action, earth pressure, wind, temperature, etc. within the design reference period shall be considered;
2 Temporary design conditions, applicable to temporary or transient conditions during structure construction, operation and maintenance, and should consider the effects of dead load, construction personnel, construction machinery, and racking equipment;
3 Accidental design conditions are applicable to abnormal conditions of structural use, and effects such as fire, impact, derailment, broken rails, and rockfall impacts should be considered;
4 Earthquake design situation, applicable to the situation when the structure is subjected to an earthquake, the mechanical analysis and structural checking calculation of the structure under the action of the earthquake should be considered.
4.2.2 The structural design of railway engineering should adopt the corresponding structural system, reliability level, basic variables and action combination according to each design situation.
4.3 Limit state design
4.3.1 Under different design conditions, the structural design of railway engineering should meet the following requirements.
1 For the permanent design condition, the bearing capacity and normal service limit state design shall be carried out, and the fatigue limit state check shall be carried out if necessary;
2 For short-term design conditions, limit state design of bearing capacity should be carried out, and limit state of normal service can be carried out as required...
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