Function
- In a structure with multiple supports, different time history functions in terms of ground acceleration can be applied to different supports.
- In cases of long-span bridges (suspension bridge or cable stayed bridge), when the distance between the supports of a substructure is large, arrival time of seismic excitation varies. This effect can be considered using the "Multiple Support Excitation" function.
Call
From the main menu, select [Load] tab > [Type : Dynamic Loads] > [Time History Analysis Data] group > [Multiple Support Excitation]
Input
Time History Load Case Name
Select a time history analysis load case entered in "Time History Load Cases". Click the ... button to define the relevant function if the load case has not been previously defined.
Options
Time history load case of ground acceleration is applied to selected support nodes, or a previously defined time history load for specific support nodes is changed or removed.
Add/Replace : First data entry is added, and previously defined values are updated.
Delete : Values entered are deleted. Enter the delay time when the seismic excitation arrives at the structure some time after the time history analysis is initiated.
Function for Direction-X
Enter the ground acceleration in GCS X-direction.
Function Name : Select the ground acceleration to be used from the list
Scale Factor : Scale factor for the ground acceleration
Arrival Time : "Delay" time for the ground acceleration
Function for Direction-Y
Enter the ground acceleration in GCS Y-direction.
Function Name : Select the ground acceleration to be used from the list
Scale Factor : Scale factor for the ground acceleration
Arrival Time : "Delay" time for the ground acceleration
Function for Direction-Z
Enter the ground acceleration in GCS Z-direction.
Function Name : Select the ground acceleration to be used from the list
Scale Factor : Scale factor for the ground acceleration
Arrival Time : "Delay" time for the ground acceleration
Angle of Horizontal Ground Acc.
Rotational angle about GCS Z-axis signifying the direction of the horizontal component of the ground acceleration. Sign convention is (+) in the counter-clockwise direction and (-) in the clockwise direction, with reference to the X-axis.