In the STAAD 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 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
STAAD.Pro’s AS 4100 implementation does not generally check deflections. It is left to the user to check that both local member and frame deflections are within acceptable limits.
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 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 STAAD.Pro’s implementation of AS 4100.
|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 RAM Connection program currently do not support design of connections in accordance with AS 4100. In some cases connection design may govern the size of members. Such considerations are not considered in STAAD.Pro’s AS 4100 and should be checked by separately.
D2.B.1.6 Bolts and Welds
Bolt holes and welds are not generally considered in STAAD.Pro’s AS 4100 member design.