Mats (rafts)
Question: How do I design a mat foundation?
Answer: The Mat Foundation Tutorial introduces the concepts for mat design.
Question: Does Concept ignore soil tension?
Answer: You can reduce the tension by iteration. The tension gets closer to zero with an increase in the number of iterations.
See Zero tension iteration options for more information.
Question: Does Concept design for soil heave?
Answer: Not directly. You could draw spring supports that approximate varying soil support.
Question: Do I need to draw the columns above in a mat foundation model?
Answer: No, but it is a good idea. It ensures a node is placed at that location where there is likely to be a heavy point load.
Question: Can Concept design for pile supports?
Answer: Yes. Use either (flexible) columns under, or point springs. Skin friction is not considered.
Question: Can Concept design for pile and mat (raft) action together?
Answer: Yes, but the results could be very susceptible to variations in geotechnical parameters. For example, if the soil’s stiffness is overestimated, the actual pile reactions could be significantly underestimated. Use caution.
Question: Can the soil stiffness vary?
Answer: Yes. You can vary the stiffness in two directions. See Area spring properties .
Question: Where do I select the allowable soil bearing pressure?
Answer: This is not an input parameter. You need to look at soil bearing pressure plans (which have a maxima / minima legend) to assess the maximum pressures. Also, see the FAQ on Soil bearing .