Once the displacement time-history record is obtained from an acceleration record, ground motion may be applied to specific support restraints through manual multi-support excitation, described as follows:

1. At joints of interest, define a load pattern. This load pattern should apply unit values of joint displacement in the direction of applied acceleration.

2. Restrain these joints only in the direction of loading.

3. Create a time-history function which will describe variation of the joint displacements in time.

4. Define a time-history load case which specifies both the displacement and the time function, as shown in Figure 1:

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See Also

• Displacement-record conversion – Displacement time-history record

• Support settlement – Joint displacement and restraint