Precast member design groups

Note: The use of suitable design groups for precast members is recommended. Using design groups will help speed the overall design process and allow for identical reinforcement amounts to be provided for each element within the group.

Why use precast design groups?

Precast beams and columns are put into groups for two reasons:

For editing purposes - individual design groups can be selected and displayed graphically so that their properties can be changed as a group in the properties window.
For design - to standardise designs, reduce processing time, and reduce the volume of output created.

A fixed set of rules are used to automatically determine member groups: for example beams must be of similar spans, columns must have the same number of stacks. Members in all member groups must be of similar lengths and cross-section.

Note: Although precast members are automatically grouped for ease of editing, the use of groups for design is optional and can be deactivated if required: From the Design tab, click Settings> Design Groups, then select or unselect concrete beams and/or concrete columns as required.

Activating precast member design groups

Precast beam and column design groups are activated as follows:

From the Design tab, click Settings> Design Groups
Select concrete beams and/or concrete columns to activate precast beam and/or precast column design groups.

Group management

Automatic Grouping

Precast beams and columns are grouped automatically according to a fixed set of requirements.

In Model Settings > Grouping the user defined maximum length variation is used to control whether elements are sufficiently similar to be considered equivalent for grouping purposes.

Manual/Interactive Grouping

After assessing the design efficiency of each group, you are able to review design groups and make adjustments if required from the Groups tab of the Project Workspace.

See: Manage groups in the Project Workspace

Note: When manually adding members to a group, the order in which they are added will incrementally affect the average length within the group, (which is then compared to the maximum length variation). Therefore, if members are not being added as you expect, try adding them in a different order.

Regroup ALL Model Members

If you have made changes in Design Settings 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!

Precast design group requirements

Precast member design groups are formed according to the following rules:


Member type	Design group rules
Precast beam	A beam element may be in only one design group. Design groups may be formed from single span or multi-span continuous beams. All beam elements in the group must have an identical number of spans. For each individual span all beam elements in the group must have an identical cross section, including flange width where appropriate, and span length. All beam elements in the group must have identical material properties.
Precast column	A column element may be in only one design group. All column elements in the group must have an identical number of stacks. For each individual stack all column elements in the group must have an identical cross section, and stack length. All column elements in the group must have identical material properties.