spring support

[howard.irons]

Hi, is it possible or necessary to define a spring support with a negative stiffness (eg -500kN/m).

For example, for a case with an upward load on a horizontal beam, producing a downward reaction, should that support be assigned the stiffness in the downward (ie -ve) direction?

Or is the stiffness value irrespective of the direction of the applied load, hence a positive value is OK.

My case is a vertical member, with an applied moment at one end, which introduces lateral forces at the restraints along the length of the member. It's a similar case to the above, except in the vertical, rather than horizontal plane.

Thanks

[Rafacascudo]

The spring value is always positive. But if the supports works in only one direction you can use the "uplift" option which is available on all sorts of supports types in RSA.

regular supports . bar elastic ground and , or foundation elasticity for panels