Use the Time Dependent Properties form to display or specify the notional size parameters for the frame section or area section. Notional size is used for creep and shrinkage time-dependent analysis to determine the rate moisture can move through a section. Notional size is defined by the equation h = 2A/P, where h is the notional size, A is the cross-sectional area, and P is the cross-sectional perimeter. For a thin-walled frame section, h is on the order of the section thickness. For a circular section, h is equal to the radius. For a shell section, h is usually the thickness of the section.
Choose one of the following options:
None: Creep and shrinkage are not computed for this section
Auto: Notional size is computed automatically for the section. You may specify a scale factor to multiply the automatic value if desired.
User: Specify the notional size you want to use for this section. The automatic value will be ignored.
For frame sections, the automatic value is computed from the area and perimeter of the section as h=2A/P.
For shell sections, the automatic value is taken as the thickness of the section. For the homogeneous shell sections (thin/thick plate/shell/membrane), the membrane thickness is used unless thickness overwrites have been applied to the shell object, in which case the interpolated values of the thickness overwrites are used for the affected objects. For the layered shell section, time-dependent behavior is not currently supported.
The Time Dependent Properties form is currently available for the steel/aluminum sections – I/Wide Flange, Channel, Tee, Angle, Double Angle, Double Channel, Pipe and Tube sections, all the concrete sections – Rectangular, Circular, Pipe, Tube, Precast I and Precast U sections, and the Shell Section Data.
To access the Time Dependent Properties form, select a specific frame type from the Add Frame Section Property form or access it via the Shell Section Data form.