Steel members are not automatically placed into design groups. They are however, automatically put into groups, primarily for editing purposes. In this way, individual groups can be selected and displayed graphically so that their properties can be changed as a group in the properties window.
If required, grouping can also (optionally) be utilized in order to design steel member types according to their groups.
In order to use grouping for this second purpose, you should first ensure that your groups are configured so that each group only contains those members that you intend to eventually have the same section size applied.
Note: Grouped design is optional and can be activated if required, via Design Options> Design Groups
Note: A fixed set of rules are initially used to determine the automatic member grouping: for example beams are designated as either direction 1 or direction 2, are of a similar span, material grade and construction type, columns have the same number of stacks etc. You can manually edit groups.
What happens in the group design process?
When the option to design a specific steel member type using groups is checked, for that member type:
In each design group the first member to be designed is selected arbitrarily. A full design is carried out on this member and the section size so obtained is copied to all other members in the group.
These other members are then checked one by one to verify that the section size is adequate for each and if this proves not to be the case, it is increased as necessary and the revised section size is copied to all members in the group.
This process continues until all members in the group have been satisfactorily checked.
A final check design is then carried out on each group member. During this process peak and individual utilizations are established.
Note: When performing the design of a group of composite beams the changes in section size may mean that for some beams the existing stud layout will no longer remain adequate. To ensure the safe and rational design of the studs, the stud design routine is re-run at the end of the group design for all beams with the stud auto-layout active in the beam properties.
Steel design group requirements
Steel member design groups are formed according to the following rules:
Design group rules
A beam element may only be in one design group
All beam elements in the group must have the same Construction/Fabrication i.e. Non-composite Rolled,
All beam elements in the group must have the same material properties
All beam elements in the group are of a similar span.
All beam elements in the group must be aligned in the same direction.
Groups that align with Dir 1 are automatically placed under the 'Dir1' main group heading
Groups that align with Dir 2 are automatically placed under the 'Dir2' main group heading
Groups that don't align with either Dir 1, or Dir 2 are automatically placed under the 'Other' group heading
A column element may only be in one design group
All column elements in the group must have the same Construction/Fabrication i.e. Non-composite Rolled,
All column elements in the group must have the same material properties
All column elements in the group are of a similar length
All column elements in the group must have the same number of stacks
Steel members are grouped automatically.
In Model Settings>Grouping the user defined Maximum length variation is used to control whether elements are sufficiently similar to be considered equivalent for automatic grouping purposes.
To manually reassign a member to a different group, locate it in the Project Workspace,Groups taband drag it to a different group.
Note: A member can only be placed into a single design group.
Note: A cross will appear if the element does not meet the Group requirements.
Regroup ALL Model Members
If you have made changes in Design Options that affect grouping, you can update the groups accordingly from the Groups tab of the Project Workspace by clicking Re-group ALL Model Members.
Note: Any manually applied grouping will be lost if you elect to re-group!