2 Design format
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Statutory Documents - IMO Publications and Documents - Resolutions - Maritime Safety Committee - Resolution MSC.370(93) – Amendments to The International Code for The Construction and Equipment of Ships Carrying Liquefied Gases In Bulk (IGC Code) – (Adopted on 22 May 2014) - Annex - Amendments to The International Code for The Construction and Equipment of Ships Carrying Liquefied Gases In Bulk (IGC Code) - Appendix 5 – Standard for the Use of Limit State Methodologies in the Design of Cargo Containment Systems of Novel Configuration - 2 Design format

2 Design format

  2.1 The design format in this standard is based on a Load and Resistance Factor Design format. The fundamental principle of the Load and Resistance Factor Design format is to verify that design load effects, Ld , do not exceed design resistances, Rd , for any of the considered failure modes in any scenario:

  Ld ≤ Rd

 A design load Fdk is obtained by multiplying the characteristic load by a load factor relevant for the given load category:

  Fdk = γf • Fk

 where:

γf = is load factor; and
Fk = is the characteristic load as specified in part B and part C of chapter 4 of this Code.

 A design load effect d L (e.g. stresses, strains, displacements and vibrations) is the most unfavourable combined load effect derived from the design loads, and may be expressed by:

  Ld = q(Fd1 ,Fd2 ,...,FdN )

 where q denotes the functional relationship between load and load effect determined by structural analyses.

 The design resistance Rd is determined as follows:

 where:

Rk = is the characteristic resistance. In case of materials covered by chapter 6 of this Code, it may be, but not limited to, specified minimum yield stress, specified minimum tensile strength, plastic resistance of cross sections, and ultimate buckling strength;
γR = is the resistance factor, defined as γR = γm • γs ;
γm = is the partial resistance factor to take account of the probabilistic distribution of the material properties (material factor);
γs = is the partial resistance factor to take account of the uncertainties on the capacity of the structure, such as the quality of the construction, method considered for determination of the capacity including accuracy of analysis; and
γC = is the consequence class factor, which accounts for the potential results of failure with regard to release of cargo and possible human injury.

  2.2 Cargo containment design shall take into account potential failure consequences. Consequence classes are defined in table 1, to specify the consequences of failure when the mode of failure is related to the Ultimate Limit State, the Fatigue Limit State, or the Accident Limit State.

Table 1 Consequence classes

Consequence class Definition
Low Failure implies minor release of the cargo.
Medium Failure implies release of the cargo and potential for human injury.
High Failure implies significant release of the cargo and high potential for human injury / fatality.
Parent topic: Appendix 5 – Standard for the Use of Limit State Methodologies in the Design of Cargo Containment Systems of Novel Configuration
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