Preface
This is the eighth edition of CSA S16, Design of steel structures. It supersedes the previous limit states editions published in 2009, 2001, 1994, 1989, 1984, 1978, and 1974. These limit states design editions were preceded by seven working stress design editions published in 1969, 1965, 1961, 1954, 1940, 1930, and 1924. The 1969 working stress design edition was withdrawn in 1984, from which point the design of steel structures in Canada has been carried out using limit states design principles.
This Standard is appropriate for the design of a broad range of structures. It sets out minimum requirements and is expected to be used only by engineers competent in the design of steel structures.
The following is a list of some of the more important changes made in this edition:
a) Clause 1.4 specifically prohibits the use of other standards for fabrication, erection and inspection.
b) The definition of “snug-tightness” has been clarified.
c) Information required on design documents has been augmented.
d) ASTM grades A500/A500M, A1085 and A913/A913M have been added as permissible steel grades for design.
e) The fire endurance design requirements have been restated to be in compliance with the NBCC.
f) Requirements under impulse loading have been added.
g) The initial misalignment of members at brace points has been clarified.
h) A calculation for the net area of a slotted HSS member has been given.
i) The minimum b/t for bearing stiffeners has been added.
j) The clause permitting a joist manufacturer to determine the joist resistance by testing has been removed.
k) Provisions for column stiffeners opposite a rigidly connected beam by bolting have been provided.
l) Requirements for zinc-aluminum coated assemblies have been incorporated.
m) The use of plate washers in lieu of hardened washers is permitted in oversize or slotted holes.
n) The use of non-matching electrodes is permitted with reference to W59 for locations where this is permitted.
o) Clause 24 that referred to joint surface conditions for field welding in the previous edition has been removed and is now covered in CSA W47.1.
p) The factored resistance of anchor rods in bearing has been referred to CSA A23.3 to be consistent with other Canadian design standards.
q) A clarification on fatigue calculations has been made to include bending moments due to joint eccentricities.
r) An upper limit on the design force of single-storey buildings’ roof diaphragms has been provided.
s) A minimum Charpy V-notch value has been specified for weld of primary members and connections.
t) A maximum sulfur content for ASTM A913 used in seismic-resisting systems is specified.
u) Additional criteria for joint connections have been added to ductile moment-resisting frames, limited ductility moment-resisting frames, and moderately ductile concentrically braced frames.
v) The design of link beams for ductile eccentrically braced frames has been expanded.
w) Detailing information for limited ductility plate walls has been given.
x) Annex K Structural design for fire conditions has been updated.
y) The clauses related to pin-connected members have been revised to clarify the net section and resistance requirements.
A commentary on this Standard, prepared by the Canadian Institute of Steel Construction with contributions from many members of the Technical Committee, comprises Part 2 of the Institute’s Handbook of Steel Construction.
This Standard is intended to be used with the provisions of the 2015 edition of the National Building Code of Canada (NBCC), specifically Clause 7, which references the NBCC for load factors, load combinations, and other loading provisions.
Scope and application
1.1 General
This Standard provides rules and requirements for the design, fabrication, and erection of steel structures. The design is based on limit states. The term steel structures refers 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 also applies to structural steel components in structures framed in other materials. The clauses related to fabrication and erection serve to show that design is inextricably a part of the design-fabrication-erection sequence and cannot be considered in isolation. For matters concerning standard practice pertinent to the fabrication and erection of structural steel not covered in this Standard, see Annex A.
1.2 Requirements
Requirements for steel structures such as bridges, antenna towers, offshore structures, and cold-formed steel structural members are given in other CSA Group Standards.
1.3 Application
This Standard applies unconditionally to steel structures, except that supplementary rules or requirements might be necessary for
a) unusual types of construction;
b) mixed systems of construction;
c) steel structures that
i) have great height or spans;
ii) are required to be movable or be readily dismantled;
iii) are exposed to severe environmental conditions;
iv) are exposed to severe loads such as those resulting from vehicle impact or explosion;
v) are required to satisfy aesthetic, architectural, or other requirements of a non-structural nature;
vi) employ materials or products not listed in Clause 5; or
vii) have other special features that could affect the design, fabrication, or erection;
d) tanks, stacks, other platework structures, poles, and piling; and
e) crane-supporting structures.
1.4 Other standards
The use of other standards for the design, fabrication, erection, and/or inspection of members or parts of steel structures is neither warranted nor acceptable except where specifically directed in this Standard. The design formulas provided in this Standard may be supplemented by a rational design based on theory, analysis, and engineering practice acceptable to the regulatory authority, provided that nominal margins (or factors) of safety are at least equal to those intended in the provisions of this Standard. The substitution of other standards or criteria for fabrication, erection, and/or inspection is expressly prohibited unless specifically directed in this Standard.
1.5 Terminology
In this Standard, shall is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; should is used to express a recommendation or that which is advised but not required; and may is used to express an option or that which is permissible within the limits of the Standard.
Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material.
Notes to tables and figures are considered part of the table or figure and may be written as requirements.
Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.
