Seismosoft | Earthquake Engineering Solutions

While I was performing Dynamic Time history analysis on an 8-Storey, 3-Bay 2D RC frame under Kobe excitation, in the graphical output of processor which shows the Real-time Drawing of the Deformed Shape sth unexpected happened. In the graphical section it showed the structure is moving from side to side [:0]. I should mention that RESTRAINTS are all fine and are checked so many times.
When I looked at graphical window, it seemed that the structure is moving side to side on a roller-coaster. I'm sure that restraints are fine.
Now, I'm asking, is it just a graphical flaw, or it is sth which affects the results???[?]

When subjected to earthquake action at its base, structures obviously do feature rigid body motion, in addition to relative deformation.

Typically, such rigid body motion is of no interest for engineering applications, hence its plotting is redundant.

In order to disable such rigid-body plotting, and whilst in the Processor module, you need simply to enter the 'Deformed Shape Settings' dialog box, and activate the option 'Fix Position of First Node' (which should thus be a node at the base of the structure, in order for this option work).

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