Longitudinal edge refers to the number of ends (1 or 2) of the element (flange outstand or web, black shaded area, Figure 1) that are “supported”, i.e. connected to the rest of the section.
These rules can therefore be extended to work with shapes other than those shown in the table.
Uniform compression is taken to mean both ends of the plate element are in compression.
For an edge supported at one side only, row two states “Maximum compression at unsupported edge, zero stress or tension at supported edge”. Maximum is meant here in the sense of the maximum possible, i.e. at the yield stress, not the larger of the two compressions. The supplement notes, “The values for uniform compression may be used conservatively for other stress distributions” so use row 2 only for the situation described and uniform compression for all other situations. This gives rise to the following implementation:
| Supported Edge | Unsupported Edge | Row |
|---|---|---|
| Compression | Compression | 1 |
| Compression | Tension | 1 |
| Tension | Compression | 2 |
| Tension | Tension | N/A |
(consider zero stress to be tension)
In order to calculate the stress distributions, take the applied load and scale the strains to the yield strain for the elastic stress distribution and to the plastic collapse strain for the plastic stress distribution.
The Plasticity limit is to be calculated using the plastic stress distribution and the Yield limit is to be calculated using the elastic stress distribution.
The Deformation limit is a serviceability limit state briefly mentioned in Clause 5.1.4 so the elastic stress distribution will be used to calculate this.
NB: Row 4 is equivalent to Row 5 for the case where \(r_{p} = 0.5\) and \(r_{e} = 0.5\), but doesn’t give precisely identical values.
\(b\) is taken as the length between fillets/welds, whereas \(d_{1}\) is taken as the full width of the element (see Figure 2).
