Experimental analysis of rocking shallow foundation on cohesive sand

One of the most important parameters affecting nonlinear soil-structure interaction, especially rocking foundation, is the vertical factor of safety (F.Sy). In this research, the effect of F.Sy on the behavior of rocking foundations was experimentally investigated. A set of slow, cyclic, horizontal loading tests was conducted on elastic SDOF structures with different shallow foundations. Vertical bearing capacity tests also were conducted to determine the F.Sy more precisely. Furthermore, 10% silt was mixed with the dry sand at a 5% moisture content to reach the minimum apparent cohesion. The results of the vertical bearing capacity tests showed that the bearing capacity coefficients (Nc and Ny) were influenced by the scaling effect. The results of horizontal cyclic loading tests showed that the trend of increase in capacity was substantially related to the source of nonlinearity and it varied by changing F.Sy. Stiffness degradation was found to occur in the final cycles of loading. The results indicated that the moment capacity and damping ratio of the system in models with lower F.Sy values depended on soil specifications such cohesiveness or non-cohesiveness and were not just a function of F.Sy.