Chronological sequences

Mac & PC

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Chronological Sequence

At a glance: The use of the application to follows a chronological sequence of events is described in  General – Chronological Sequence. Here procedures specific to the Mac and PC for adopting a stage load and setting up an initial state are described.

Time affects

For the steps to apply a Time Affect Set that includes creep computation see General – Time Affect Set – Applying a Time Affect Set.

Adopting a stage load

The initial state and stage distortion facilities have a purpose illustrated by two parallel structural members in close association but structurally independent; each having a loading and corresponding distortions. At a particular instant in the construction process these two members are joined so they act as one structural member. Immediately after that instant the resulting member has a loading that is the combined affect of the two loadings before and each component has the same distortion as before that instant.

The facilities use three XSF files; one for each of the contributing members cross-sections, and one for the resulting member cross-section.

The procedure is:

  1. For each of the contributing members set up the XSF file including load cases and Time Affect Sets for the chronological sequence before the members are joined and save the file.
  2. With each of the contributing member XSF files add a Load-case, give it a name indicating its purpose and set it up with the envisaged loading at the instant members are joined and save the file.
  3. With each of the contributing members XSF files:
  • Do the computation for the chronological sequence before the members are joined
  • Compute the load case for the instant the members are joined
  • In the Load-case list on the main dialog make sure the load case for the instant the members are joined is selected.
  • Click on main menu Load Cases “Adopt stage load” item.
  • save the file.
  1. Open the file for the resulting member cross-section.
  2. Delete all the components and all the materials that remain from a previous cycle of the design process. The Load-cases from the previous cycle should remain and can be used again.
  3. For each of the contributing members (with the resulting member file open):
  • Click the main menu “Components” menu item “Import from another XSF”. This should bring up the “Other XSF files” dialog.
  • Click on the “Open other XSF” button. This should bring up the standard “Open file” dialog.
  • Navigate to, and open the file for the contributing member cross-section. This should populate the various list boxes in the “Other XSF files” dialog.
  • In the “Components to import” list select each component and then click on the “Import” button. This should copy the components descriptions into the resulting member and also the materials they reference (unless there is a material of the same name already there).
  • Click on the close button to close the “Other XSF files” dialog.
  • Save the file.

This procedure sets up the initial state of the resulting member.

A further step is a check and also illustrates the meaning of this. Use a load case to do a computation with the “Utility: Curvatures and one strain” method with all three distortion variables set to zero. This should result in a loading that is the combined affect of the loadings on the contributing members.

The aging of concrete

The stress/strain relationship of concrete changes as the concrete ages. A sequence of xsf files could be set up that each have a set of material descriptions appropriate to different points in the chronology. “Materials” on the main menu has an item “Import from another xsf file”. This leads to a dialog where the other file can be stipulated and it includes a button labeled “Overwrite all” intended for this purpose.