ISO/TC 98/SC 2 - Reliability of structures

This document specifies the principles regarding the design of seismically isolated structures under earthquake effects. This document also describes the principles of construction management and maintenance, since proper construction management and maintenance are important for realizing high quality seismic isolation structures. This document is not applicable to bridges and LNG tanks, although some of the principles can be referred to for the seismic isolation of those structures. This document is not applicable to seismic isolation structures that reduce the vertical response to earthquake ground motions, since this document mainly specifies seismic isolation structures that attenuate the horizontal response to horizontal earthquake ground motions. This document is not a legally binding and enforceable code. It can be viewed as a source document that is utilized in the development of codes of practice by the competent authority responsible for issuing structural design regulations. NOTE This document has been prepared mainly for the seismically isolated structures which have the seismic isolation interface applied between a superstructure and a substructure to reduce the effect of the earthquake ground motion onto the superstructure. In most cases, the substructure refers to the foundation of the structure. However, the substructure in this document consists of a structural system below the isolation interface that has been designed with sufficient rigidity and strength. Examples include locating the isolation interface in a mid-storey of the building or above the bridge piers (see Annex E).

This document establishes the basic principles for the determination of deformations of buildings at the serviceability limit state when formulating national standards and recommendations. This document contains information on how serviceability for buildings and building elements is dealt with in some national standards.

This document specifies general principles of risk assessment for systems involving structures. The focus is on strategic and operational decision-making related to design, assessment, maintenance and decommissioning of structures. This also includes formulation and calibration of related codes and standards. Systems involving structures can expose stakeholders at various levels in society to significant risks. The aim of this document is to facilitate and enhance decision-making with regard to monitoring, reducing and managing risks, and preparing for emergency in an efficient, cost-effective and transparent manner. Within the broader context of risk management, risk assessment provides decision-makers with procedures to determine whether or not, and in what manner, it is appropriate to treat risks. This document provides a general framework as well as a procedure for identifying hazards and estimating, evaluating and treating risks of structures and systems involving structures. This document also provides a basis for code writers as well as designers to set reasonable target-reliability levels, such as stated in ISO 2394, based on the result of risk considerations. For existing structures, it is intended that assessment of the risks associated with the events that were not considered in the original design or with changes in use be implemented according to the principles stated in this document. This document can also be used for risk assessment of exceptional structures upon specific adaptation and detailing, the design of which is not usually within the scope of existing codes.

This document provides the requirements for structural design and procedures following a semi-probabilistic approach that conform to the general principles for structural reliability as stipulated by ISO 2394. The scope of requirements and procedures are accordingly limited to the design of structures for which sufficient knowledge and experience are commonly available on design and construction practice to ensure that target levels of reliability account for the nature and consequences of structural failure. Situations outside these limitations are covered by ISO 2394. The methods that are included in this document are the semi-probabilistic limit states approaches that are proven to achieve sufficient and consistent levels of structural reliability. This document relies on standardized procedures for the characterization of the load bearing performance of the structures within its scope. Sufficient information is needed on uncertainties of design variables and models to be able to derive semi-probabilistic design measures for verification of structural reliability within the scope of this and the related design standards.

ISO 2394:2015 constitutes a risk- and reliability-informed foundation for decision making concerning design and assessment of structures both for the purpose of code making and in the context of specific projects.

ISO 13822:2010 provides general requirements and procedures for the assessment of existing structures (buildings, bridges, industrial structures, etc.) based on the principles of structural reliability and consequences of failure. It is based on ISO 2394. ISO 13822:2010 is applicable to the assessment of any type of existing structure that was originally designed, analysed and specified based on accepted engineering principles and/or design rules, as well as structures constructed on the basis of good workmanship, historic experience and accepted professional practice. The assessment can be initiated under the following circumstances: an anticipated change in use or extension of design working life; a reliability check (e.g. for earthquakes, increased traffic actions) as required by authorities, insurance companies, owners, etc.; structural deterioration due to time-dependent actions (e.g. corrosion, fatigue); structural damage by accidental actions (see ISO 2394). ISO 13822:2010 is also applicable to heritage structures provided additional considerations shown in Annex I are taken into account. ISO 13822:2010 is applicable to existing structures of any material, although specific adaptation can be required depending on the type of material, such as concrete, steel, timber, masonry, etc. ISO 13822:2010 provides principles regarding actions and environmental influences. Further detailed considerations are necessary for accidental actions such as fire and earthquake. ISO 13822:2010 is intended to serve as a basis for preparing national standards or codes of practice in accordance with current engineering practice and the economic conditions.

ISO 13823:2008 specifies general principles and recommends procedures for the verification of the durability of structures subject to known or foreseeable environmental actions, including mechanical actions, causing material degradation leading to failure of performance. It is necessary to insure reliability of performance throughout the design service life of the structure. Fatigue failure due to cyclic stress is not within the scope of ISO 13823:2008.

ISO 10137:2007 gives recommendations on the evaluation of serviceability against vibrations of buildings, and walkways within buildings or connecting them or outside of buildings. It covers three recipients of vibrations: human occupancy in buildings and on walkways; the contents of the building; the structure of the building. It does not include bridges that carry vehicular traffic, even in conjunction with pedestrian traffic, nor the design of foundations or supporting structures of machinery.

ISO 13824:2009 specifies general principles on risk assessment of systems involving structures. The focus is on strategic and operational decision-making related to design, assessment, maintenance and decommissioning of structures. This also includes formulation and calibration of related codes and standards. Systems involving structures can expose stakeholders at various levels in society to significant risks. The aim of ISO 13824:2009 is to facilitate and enhance decision-making with regard to monitoring, reducing and managing risks in an efficient, cost-effective and transparent manner. Within the broader context of risk management, risk assessment provides decision makers with procedures to determine whether or not and in what manner it is appropriate to treat risks. ISO 13824:2009 provides a general framework as well as a procedure for identifying hazards and estimating, evaluating and treating risks of structures and systems involving structures. ISO 13824:2009 also provides a basis for code writers as well as designers to set reasonable target-reliability levels, such as stated in ISO 2394, based on the result of risk considerations. For existing structures, assessment of the risks associated with the events that were not considered in the original design or with changes in use shall be implemented according to the principles stated in ISO 13824:2009. ISO 13824:2009 can also be used for risk assessment of exceptional structures, the design of which is usually beyond the scope of existing codes.

ISO 22111:2007 specifies the general requirements for the structural design of buildings and industrial and civil engineering structures using reliability-based concepts. ISO 22111:2007 is applicable to the design of complete structures, the structural elements making up the structure and the foundation. Information on the assessment of existing structures is given in ISO 13822.

Gives recommendations and covers three recipients of vibrations: a) human occupancy in buildings and on pedestrian bridges, b) the contents of the building, c) the structure of the building. Applies to buildings, pedestrian bridges and walkways found within buildings or connecting them.

Establishes the basic principles that should be adopted when setting up national standards, regulations and recommendations for the deformation of buildings at the limit states of serviceability. Refers to the deformations at the serviceability limit states of buildings such as dwellings, offices, public buildings, and factories. Does not refer to the deformations of bridges, roads, masts, underground works, non-residential farm buildings, or special-purpose buildings such as atomic power stations or industrial plant.