STAAD.Pro Help

Define (Time History) Parameters dialog

Used to define time step, damping, and arrival times for time history loads.

Opens when the Time History > Parameters tool is selected in the Dynamic Specifications group on the Loading ribbon tab.

Time Step

Specify a solution time step to be used in the step-by-step integration of the uncoupled equations.  The default value of Time Step is determined as explained in TR.31.4 時刻歴荷重の定義 .


The following options are available for specifying damping:

  • Damping – This is to be used for specifying a single modal damping ratio which will be applied to all modes. The default value is 0.05.
  • CDAMP - If a damping ratio has already been specified under CONSTANTS based on the type of material in the structure, that value may be used directly in the time history analysis. Check this option for that purpose.
  • MDAMP - In we wish to utilize individual damping ratios for individual modes, that is achieved through the means of the MDAMP option. The first step to doing this is the specification of those individual damping ratios, as explained under TR.26.4 モーダル減衰の情報 , and is done graphically by using the Modal Damping tool on the Loading ribbon tab. If this first step has been completed, the instruction to utilize MDAMP is done by selecting this option shown above.
Arrival Time

Specify values of possible arrival times of the various dynamic load types. The arrival time is the time at which a load type begins to act at a joint (forcing function) or at the base of the structure (ground motion). The same load may have different arrival times for different joints and hence all these values must be specified here. The arrival times and time-force pairs for the load types are used to create the load vector needed for each time step of the analysis.


Adds the specified load details to the currently selected load case in the Load dialog and closes the dialog.


Closes the dialog without adding any load data.


Opens the STAAD.Pro Help window.