Multi-Support Excitation Pattern

The Multi-Support pattern allows similar or different prescribed ground motions to be input at various supports in the structure. In OpenSees, the prescribed motion is applied using single-point constraints, the single-point constraints taking their constraint value from user created ground motions.

<uml> abstract class TimeSeries LoadPattern <|-- MultipleSupportExcitation MultipleSupportExcitation o- GroundMotion MultipleSupportExcitation o- ImposedMotionSP ImposedMotionSP --- GroundMotion SP_Constraint <|-- ImposedMotionSP GroundMotion o- TimeSeries </uml>

The command to generate a multi-support excitation contains in { } the commands to generate all the ground motions and the single-point constraints in the pattern. The command is as follows:

pattern MultipleSupport $patternTag {

groundMotion...

imposedMotion...

...

}

NOTES:

1. The results for the responses at the nodes are the ABSOLUTE values, and not relative values as in the case of a UniformExciatation.
2. The non-homogeneous single point constraints require an appropriate choice of constraint handler.

---

$patternTag	unique tag among load patterns
groundMotion...	command to generate a ground motion
imposedMotion ...	command to generate an imposed motion

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Code Developed by: fmk