Mr. Monroe,

Thanks for your expounded remarks.....

I tend to want to lock down or provide vertical restraint wherever possible/ practicable so as to remove this issue from the plate of design issues.

In the old days (Punch Cards) systems were quite commonly "floated" based on T only displacements and W only loads... many a spring can was used some perhaps unnecessarily to the detriment of the installed systems cost and ongoing maintenance.

I have used the load case setup on and off for curiosities sake that Rich has laid out and it has agreed with the inactive support removed analysis. I suspect that it should be fine... however eliminating the lift-off eliminates the need for this unique load case.... I have always preferred simpler whenever possible/practical.

I do not agree with the philosophy that only "good" supports don't lift off. Often times refineries will have turn-around supports for the cold posistion that assist in maintenance. These act as a firm boundary in the cold posistion and cannot be ignored.

In the end this condition creates a bi-polar stress maybe its a collapsing load and maybe its a self-limiting thermal displacement... our job is to figure out what is most likely... and not to ignore the problem as many do.

In code parlance your remarks might be construed then as either a negative with comment or maybe an approved with comment. Many times I have had a more difficult time reconciling ballots that are approved with comment!

Keep up the good thinking....