Some Remarks on the Optimum Design of Piled Rafts

Satisfactory methods of analysis of the raft-pile-soil interaction are available by now. The search for design criteria more rational and economic of the conventional ones is thus justified. The present paper discusses the guidelines for an optimum design. It is suggested that different criteria should be applied for "small" and "large" piled rafts. In the former case, the primary reason to add piles is that of achieving a sufficient factor of safety; in the latter the addition of piles is essentially intended to reduce mean and/or differential settlement. In both cases, it is shown that substantial savings can be achieved in respect to the present design approach, by considering the raft-soil-pile interaction.