Simple Approach to Static and Seismic Design of Piled Rafts

Current design of piled rafts often neglects a number of aspects well known in scientific literature, sometimes leading to increased costs without appreciable increase in performance. This work makes an attempt to partially fill this lack between State of Art and State of Practice; to this end, the paper briefly recalls available simple design methods regarding both geotechnical and seismic issues and proposes a novel simple procedure to estimate the loadsettlement curve of a piled raft as well as the load sharing between piles and raft for vertical centered loads. The method has been validated through comparison with numerical and experimental data and applied to a case history; it will be shown that the proposed procedure, despite its simplicity, is able to account for the non-linearity in the soil behavior, the latter being responsible of progressive variation of the load sharing with increasing applied top load. Further, regarding seismic issues, simplified formulae from past works are recalled and discussed.