General Settings
The General Settings tab is used to control the basic properties of the current project. The following sections are available
- Title
- The title is included header of all output files.
- Notes
- The notes are only meant to help maintain one's sanity and are not used in any way.
- Filename prefix
- The filename prefix is prepended onto the standard filenames. Allowing for
the filenames to be descriptive of the calculation.
- Units
- The units system changes the units of both the input and output between Metric and
English. Changing the units system does not provide conversion between the two different systems.
- Save motion data within the input file check box
- When this check box is checked, the
time-series data is included in the data file. This increases the size of the file, but allows for
the file to be easily transfered.
- Calculation Method
-
- The calculation method switches between the time-domain and random
vibration theory methods.
- Vary the properties check box
-
- Allows the user to vary the properties of the site.
- Number of realizations
-
- The number of sites profiles that are generated. For each site
profile all of the motions are propagated through the site.
- Vary the non-linear soil properties check box
-
- Determines whether or not the non-linear soil properties
(shear-modulus reduction and damping curves) are varied.
- Vary the site profile
-
- Determines whether or not the site profile (shear-wave velocity,
layer thickness, and depth to bedrock) are varied.
Strata performs equivalent-linear site response analysis which assumes
linear-elastic wave propagation with strain compatible properities. The
analysis is an iterative procedure which changes the properties in the
layer such that properties use the previously computed effective strain for
the layer.
- Effective strain ratio
-
- The effective strain ratio rates the maximum strain in the layer to
the effective strain used for the equivalent non-linear soil
properties. [Default value 0.65]
- Error tolerance
-
- The error tolerance is one of the exit conditions in the
equivalent-linear site response loop. Once the error in both the
damping and shear-modulus in all layers is below this level the
iterative portion of the analysis stops. [Default value 1%]
- Maximum number of iterations
-
- The maximum number of iteration is the other exit conditions for
the equivalent-linear site response loop. After reaching this number
of iterations, the loop exits and a warning message is printed. [Default value 8]
Strata allows for variation of the layering thickness and shear-wave
velocity therefore it divides the velocity layers into sub-layers for the
wave propagation. The thickness of these sublayers is controlled by the
maximum frequency and wavelength fraction. See technical manual for more
information.
- Maximum frequency
- Maximum frequency of engineering interest. [Default value 20]
- Wavelength fraction
-
- The number of wavelengths contained within a sublayer. Typically
ranges from 1/5 to 1/10, values less than 1/3 are not recommended.
[Default value 0.2]