Spring supports and Gravity Loading in SimSolid

Dency Dela Cruz

Hi,

I am currently working on a model of a concrete foundation that is partly embedded in soil. The aim is to determine the overall foundation stiffness by means of applying a force on certain points on the foundation and measuring the resultant deflections to derive a stiffness value.

To account for the soil, I am using spring supports with stiffness values derived from the modulus of subgrade reaction for the specific soil type. These spring supports are placed horizontally and vertically around the foundation surfaces embedded within the soil.

As I understand it, soils should only really be working in compression (e.g stiffness should be zero in tension). I am therefore wondering if there is a way to define the springs in SimSolid to simulate the above, similar to a one-directional spring. I note that there is also a foundation factor option but I am not sure how this works entirely. Alternatively, are there any other methods where I can fix my foundation in the -ve vertical direction but still allow for movement in the +ve vertical direction? I looked at the other constraint options (immovable, roller, and prescribed displacement) but none of these offer options of restricting motion only in one direction of an axis.

Furthermore, how do gravity loads work in SimSolid? If I don’t have this option activated, does this mean that the mass of my model is not active in the analysis?

Thank you in advance for any insight.

Chayan

Dency,

SiimSolid currently does not have compression only spring option. Would the spring with the foundation option work for you?

Yes, in a static analysis, the masses on your structure will not add to the displacement/stress, if you are not using the gravity option. when gravity is enabled the representative load will be mass x gravity.