Steel member design: Utilisation ratios
Measures of the utilisation of the member’s capacity. Remember that their values will not be directly comparable from design code to design code, and that the calculation of some of them is highly nonlinear. If any of them is greater than 1, then the member has failed.
All of the utilisations are the worst of their kind encountered along the member’s length.
Envelopes of utilisation ratios are the maximum and minimum of the utilisation ratios calculated for each permutation in the envelope.
The ratios available are:
| Ratio | Comment |
|---|---|
| Overall | worst of all the other utilisation ratios |
| Local Combined | local force/capacity interaction |
| Local Axial | |
| Local Moment Major | local major axis moment |
| Local Moment Minor | local minor axis moment |
| Local Shear Major | |
| Local Shear Minor | |
| Local Torsion | |
| Buckling Combined | buckling interaction |
| Buckling LT | lateral torsional buckling |
| Buckling Axial Major | |
| Buckling Axial Minor |