Have you ever asked, “How Do I Avoid Instability Warnings in a RISA-3D Model?” If so, then RISA News has answered your question in their article with the same title.
Have you ever received an instability warning when running a three dimensional RISA-3D model? This is because RISA-3D cannot build the stiffness matrix with the configuration you have modeled. In some cases, your model is truly unstable and in others it’s a matter of correctly modeling your structure for a 3D finite element analysis program.
Read their article for tips to avoid instabilities.
via RISA News