ONESTEEL duragal sections

D1.2.3.1 Compactness
In Clauses 5.2.3, 5.2.4, and 5.2.5 of AS 4100, sections are described as compact, non-compact or
slender. This type of categorisation provides a measure of the relative importance of yielding and local
buckling on the effective section modulus.
The tables include a column headed “compactness” where the compactness or otherwise of the sections
is indicated for a given axis of bending as follows:
C compact
N non-compact
S slender
These terms are important with respect to selecting the methods of analysis that may be used to determine
the design action effects (see Clause 4.5 of AS 4100) or in using the provisions of Section 8 of AS 4100
for designing members subject to combined actions. Clause 4.5 of AS 4100 does not currently permit
plastic analysis when designing with structural hollow sections.
Research has shown that most DuraGal hollow sections are suitable for design by plastic analysis and AS
4100 will be revised as soon as possible. In the interim, for details of the research in a case study phone
OneSteel Direct on Freecall 1800 1 STEEL (1800 1 78335) or Freefax 1800 101 141.
D1.2.3.2 Effective Section Modulus
Subsequent to the evaluation of “compactness” the effective section modulus (Z e ) is also tabulated. Z e is
determined by the requirements of Clauses 5.2.2 to 5.2.5 inclusive, of AS 4100 and is used in the calculation
of the nominal section moment capacity (M s ) as defined in Clause 5.2.1 of AS 4100.
Table D1.2.3.2 gives values of plate element slenderness limits for structural hollow sections used in the
determination of Z e in Tables D1.2-1 to D1.2-4. It should be noted that the deformation limit (λ ed ) is only
exceeded for one of the hollow sections manufactured in accordance with AS 1163 and listed in this
manual. Therefore noticeable deformations (local buckling) will not occur under service loadings except
for 150x50x2.0 product bent about the weak y-axis (λ ey = 97.9).
Section Element Residual Plasticity Yield Deformation
Stresses Limit Limit Limit
λ ep λ ey λ ed
RHS,SHS
Compression CF 30 40 90
Flange
Web CF 82 115 -
Table D1.2.3.2: Plate Element Slenderness Limits for Members Subject to Bending
The CF residual stress classification is used as DuraGal is manufactured in Australia by the cold forming
process.
DCTDHS/06
DuraGal DESIGN CAPACITY TABLES
MARCH 2002 for STRUCTURAL STEEL HOLLOW SECTIONS D1-5