Compression-only spring for frame

[JasonGeng]

Is there anybody who knows how to define line spring as compression-only spring? I tried, but it looked not working.
Any input will be appreciated.

 

[WillisV]

Use a Gap type NLink element and make sure you run a nonlinear analysis.

 

[JasonGeng]

Thanks for your help.
I tried GAP element as well, but still not working. I defined a nonlinear link (GAP type) and assigned to the frame to be analyzed. But the result showed that the spring was not functional at all. Any hints? Or anywhere I did wrong?

Thanks.

 

[JasonGeng]

I just did it!
The direction I applied the spring was wrong before.