BS 5950 Parameters dialog
Section Options tab
| Setting | Description |
|---|---|
| FL Edges of welded I or H Sections | Built-up flange sections can be designated as being built of milled plate or of flame cut (thermal cut) plate. The type of plate has an affect on the axial capacity of the section in both the RAM Steel Column program and RAM Frame, as described in footnote 2 of table 25 of BS 5950:Part1:1990, and in Note 2 of Table 22 of BS 5950-1:2000. |
| Hollow Sections | Hollow Sections can either be designated as Hot-Rolled or Cold-Formed. This selection applies to all hollow sections used in the current model. This designation affects the classification of the cross section (see table 12 in BS5950-1:2000), and the web shear interaction as described in H.3 of BS5950-1:2000. This selection has no impact on BS5950-1:1990. |
| Distance top-of-steel to axis of restraint | IBS 5950-1:2000 has changed the method in which the lateral torsional bending capacity of beams is calculated. In certain circumstances, where the tension flange of a beam is fully braced and the compression flange unbraced, the height of the restraint to the tension flange affects the bending capacity of the member (See BS 5950-1:2000 4.3.5.3c, Annex G.1. and G.2.). This will typically affect the design of cantilever or continuous members in the zone where the unbraced lower flange is in compression. The engineer can stipulate the distance from the top-of-flange (tension), to the center of the restraint of that flange, in the Section Properties tab of the BS5950 Parameters dialog. |
Modular Ratio tab
For the modular ratio used for the calculation of the composite section properties, you may specify a value to be used explicitly (Use) or the user may specify the proportions of the live loads that are to be considered long term versus short term (Calculate). If the Use option is selected, that value would be used for all composite beams. If the Calculate option is selected, the value of the modular ratio is determined based on Clause 4.1 of BS 5950:Part 3:Section 3.1:1990. The dead load applied to the composite section is all considered to be long term load. This is done for each beam individually based on its specific loads. These parameters only affect composite beam design in RAM Steel Beam Design.