Distributed parameter sensitivity of piles in nonlinear sand subjected to cyclic bending moment

The paper presents the formulation and numerical investigations of the sensitivity of maximum lateral deflection of a long pile embedded in p-y sand below the water table subjected to cyclic loading. The bending moment MP of discrete variability is applied to the pile head. The cyclicity of the pile-soil system is tackled in a quasi-static fashion. The parameters involved in the p-y soil relationship as well as the pile bending stiffness are considered as the design variables of a continuous type. The system is analysed in the scope of variational calculus based on the virtual work principle. The virtual load method is employed in the determination of the first variation of generalized deformation. The formulation leads to establishing the new sensitivity functions that are spatial integrands connected with each of the design variables. The nummerical investigations are focused on the determination of sensitivity integrands of maximum deflection caused by the changes of the design variables of the system. The characteristics of spatial senstivities associated with each design variable of the system are discussed in detail.