Analysis of load sharing behavior for piled rafts using normalized load response model

In the conventional pile design, pile cap is regarded as a structural member that connects the superstructure and piles, transferring imposed loads to the lower foundation parts. The load carrying capacity of pile cap is not in general taken into account even for direct contact condition with ground surface. In the present study, the load carrying behaviors of piled rafts are investigated focusing on the individual load-settlement responses of piles and raft on piled rafts. A settlement-based load sharing model for piled rafts is proposed using the normalized non-linear load-settlement relationship with consideration of piled-raft interaction effect. According to the proposed load sharing model, the load sharing ratio ap decreases as settlement increases with rates depending on the load capacity ratio. The values of ap are higher for higher load capacity ratios. To check the validity of the proposed load sharing model, centrifuge load tests are conducted. The values of ap calculated from the proposed load sharing model are in close agreement with measured values.