In this study, settlement analysis of pile groups by hand calculation methods were investigated. Settlement ratio, equivalent pier, and equivalent raft methods were studied. Variations in some of the calculation methods were noted, and some suggestions were given. More than thirty piled raft foundation case histories whose foundation and soil properties known have been found. The settlement of piled foundation in each case was solved by these methods. Results obtained from the calculations following different methods were presented for each case in the form of tables and graphs. Measured and calculated values were compared by making use of graphs and tables. Effect of type of piles was shown. It was tried to find out that which method is suitable under different conditions. In conclusion, suggestions for methods and calculation procedures were given.

In the present work, a settlement-based method is proposed to design piled raft foundation. The proposed design method is found to be very efficient, economical and requires less calculation time. Simple software can be used to execute all the interactions and loop calculations.<p>Unlike methods with numerical techniques, there are practically no limitations for the number of individual piles under the raft, size of the group and the group shape or layout. It can also be applied to piles with different length or piles that are located within multi-layered soils.<p>The raft is designed first according to the allowable settlement that is pre-defined by the structural requirements and with the necessary factor of safety. When raft suffers excessive settlement, then the load that causes excess raft settlement beyond the required limit is to be transferred to the fully mobilised frictional piles. <p>The fully mobilised shaft (with no end bearing) piles are designed with factor of safety close to unity since their function is only to reduce raft settlement and since the raft has an adequate bearing capacity.<p>Geometry of these piles is chosen to fully mobilise their shafts capacity with low settlement level in order to comply with load/settlement requirement and reduce raft settlement to the pre-defined level. <p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished