D2.B.1 General
In the STAAD.Pro implementation, members are proportioned to resist the design loads without exceeding the limit states of strength, stability, and serviceability. Accordingly, the most economic section is selected on the basis of the least weight criteria as augmented by the designer in specification of allowable member depths, desired section type, or other such parameters. The code checking portion of the program checks whether code requirements for each selected section are met and identifies the governing criteria.
The following sections describe the salient features of the STAAD.Pro implementation of AS 4100. A detailed description of the design process along with its underlying concepts and assumptions is available in the specification document.
D2.B.1.1 Strength Limit States
Strength design capacities (ϕRu) are calculated and compared to user-defined design action effects (S*), so as to ensure that S* ≤ ϕRu in accordance with AS 4100 3.4. Details for design capacity calculations are outlined in the sections that follow.
D2.B.1.2 Deflection Limit States
The implementation of AS 4100 in STAAD.Pro does not generally check deflections. It is left to the user to check that both local member and frame deflections are within acceptable limits.
span / deflectionratio. This can be performed using the
DFF
,
DJ1
, and DJ2
design parameters, however this is
only available for MEMBER
Design. Details are provided in the sections
that follow.D2.B.1.3 Eccentric Beam Reactions
STAAD.Pro does not automatically account for minimum eccentricity distances for beam reactions being transferred to columns as per AS 4100 4.3.4. However member offsets can be used to model these eccentricities.
Refer to TR.25.1 Member Offset Specification for further information on the Member Offset feature.
D2.B.1.4 Limit States Not Considered
The following limit states are not directly considered in for AS 4100 in STAAD.Pro.
Limit State | Code Reference |
---|---|
Stability | AS 4100 3.3 |
Serviceability | AS 4100 3.5 |
Brittle Fracture | AS 4100 3.7 |
Fire | AS 4100 3.9 |
Other Design Requirements | AS 4100 3.11 |
D2.B.1.5 Connection Design
STAAD.Pro and Bentley’s Connection Design program support the design of connections in accordance with AS 4100-1998 and 2020. However, in some cases connection design may govern the size of members. Such considerations are not considered in STAAD.Pro and should be checked by separately.
D2.B.1.6 Bolts and Welds
Bolt holes and welds are not generally considered in member design per AS 4100 in STAAD.Pro.
NSC
and NSF
design parameters are used to manually specify a reduction in net section area for compression or tension capacity calculations. These can be used to account for bolt hole area reductions. Further details are provided in the sections that follow.