Hi; The negative stress reading in the foundation is quite small, you can neglect it. If you need to make an interactive solution for the superstructure, you need to model with a raft foundation, not a single foundation. For your information, you should use a steel column when entering data with a raft foundation. You will need to place a short reinforced concrete column for the connection between the foundation, for your information. * In order to solve this situation where there is an inadequacy in the column foot joint, you can arrange the material of the plate as S355. We tried a different version in your project, check it out. Also, is the structure a tower type according to TS 498? Make sure it is normal type and make the necessary adjustments in the analysis settings tab - Wind sub-tab. It currently appears as normal type.