Why does the support have the same displacement as the pipe displacement?

Greetings, 

This is just a graphics issue with the way AutoPIPE graphics are generated and animated. 

Review the Results Grids / Report to understand what is happening to the pipe.

Any support connected to ground are rigidly mounted, even if the graphics shows otherwise. Stiffness setting is that between the base of the support spring and the node point it is connected to. Finally, gaps are amount of movement allowed before the support spring is engaged.

Regards,
Mike Dattilio
Design Analysis Engineering Group
Senior Analyst Bentley Systems Inc

So, the support displacement shown in support load floating display is pipe movement, am I understand correctly? 

Greetings, 

Correct, does not matter if it is the floating dialog, results reports, or results grids. 

The only time that the support is moving is when the support is connected to a point that has displacement. 

Regards,
Mike Dattilio
Design Analysis Engineering Group
Senior Analyst Bentley Systems Inc

Did you mean imposed displacement? "The only time that the support is moving is when the support is connected to a point that has displacement. "

So, if the support connected to ground are rigidly mounted, what the benefit of line stop support in AutoPIPE?

I've read the line stop function from this forum. 03. Why does line stop ignore friction? - AutoPIPE Wiki - AutoPIPE - Bentley Communities

I-beam is v-stop in AutoPIPE, and you said it is always mounted rigidly with the ground which means support has no displacement in axial, lateral, and vertical directions. line stop is an attachment to limit the displacement of I-beam support.

So far I've not seen the benefit of line stop now because the I beam provides restraints in all directions.

Greetings, 

You are confusing the subject. 

Let us only consider supports connected to ground. The impose support displacement is added to the base of the support. The base of the support is connected to the pipe Node point through an element that has a stiffness as mentioned on the support's dialog. 

If an impose support displacement (note there is no such thing as impose displacement, only "Imposed SUPPORT displacement) is added a node point The movement amount would only be added to the base of the support. Movement is translated to the pipe node point through the element mentioned above. Only elements with Rigid stiffness will transmit 100% of the support base movement to the pipe. Otherwise, if the support has a stiffness setting of less than Rigid, a calculated portion of the impose support displacement is absorbed by the support's connected element leaving the remaining amount of movement to be applied at the node point.   

Next modeling a line stop. You would need to model everything that makes the line stop. The WIKI page reference here assumes a typical construction detail. If your Line stop is constructed differently, then model as needed.

Finally, your original question was about supports graphically moving. This is just a graphical issue. The only time there is any movement of a support is when the node point a support is conectted to moves, or if Impose Support displacement is applied. Otherwise, the support will yield based on the support's spring rate. 

Example: 

Run an example model yourself:

1. Rigid guide support connected to ground and contains 1 inch lateral and vertical up gap. If 1x10^10 load was applied, the pipe would only move 1 inch. 

2. Same scenario above, but guide support had Stiffness = 1 lb.in, If 1x10^10 load was applied, the pipe would only move 1 inch and the remaining amount of movement was the support spring yielding. 

Regards,
Mike Dattilio
Design Analysis Engineering Group
Senior Analyst Bentley Systems Inc
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