Steel Structures for Buildings (Limit States Design)
This is the third edition of a limit states design standard for Steel Structures for Buildings in Canada. It is prepared in SI (metric) units and supersedes the previous SI edition published in 1978. Both the 1984 and 1978 editions are based on the first limit states design edition, written in imperial units, introduced in 1974. The 1974 edition, as revised, will continue to be available to provide engineers with a design standard in imperial units for some time.
When the 1974 limit states design edition was introduced, it was planned to withdraw the working stress design standard after a period of time during which designers would have the option of designing by working stress or limit state design methods. As well it was hoped that during this time general usage would gradually switch to the limit states design method. With the introduction of this 1984 edition, CSA Standard S1 6-1969, Steel Structures for Buildings, based on working stress design methods, has been withdrawn. The 1969 standard is the last of the seven working stress design editions published in 1965, 1961,1954, 1940, 1930, and 1924.
A considerable number of technical changes reflecting the latest research developments have been incorporated in this edition. These are based on an increased understanding of the behaviour of structures, members and elements, and of structural materials.
For example, major changes have been introduced in the clauses on the design of composite beams and columns and on anchor bolts. However, the basic limit states design format as set out in 1974 has proven itself in use and remains unaltered.
The clauses in the Standard relating to fabrication and erection serve to show that design cannot be considered in isolation but that it is part of the design and construction sequence.
This Standard sets out minimum requirements for steel structures as outlined in the Scope and, it is expected, will only be used by engineers competent in this field.
This Standard and the corresponding 1974 edition in imperial units have been adopted by the Associate Committee on the National Building Code as the reference standards for steel structures for Section 4.6 of the National Building Code for 1985.
This Standard has been approved as a National Standard of Canada by the Standards Council of Canada.
Scope and Application
This Standard provides rules and requirements for the design, fabrication, and erection of steel structures for buildings where the design is based on limit states. The term steel structures relates to structural members and frames that consist primarily of structural steel components, including the detail parts, welds, bolts, or other fasteners required in fabrication and erection.
This Standard applies unconditionally to steel structures for buildings except that supplementary rules or requirements may be necessary for
(a) unusual types of construction;
(b) mixed systems of construction; and
(c) steel structures that
(i) have great height or spans;
(ii) are required to be moveable or be readily dismantled;
(iii) are exposed to severe environmental conditions or possible severe loads such as those resulting from vehicle impact or chemical explosion;
(iv) are required to satisfy aesthetic, architectural, or other requirements of a nonstructural nature;
(v) employ materials or products not listed in Clause 5; or
(vi) have other special features that could affect design, fabrication, or erection.
A rational design based on theory, analysis, and engineering practice, acceptable to the regulatory authority, may be used in lieu of the formulae provided in this Standard. In such cases the design shall provide nominal margins (or factors) of safety at least equal to those intended in the provisions of this Standard (see Appendix E).