a method for determination of the fundamental period of layered soil profiles

In this study, a method is proposed to determine the fundamental period of layered soil profiles. a model considering the layered soil as shear type structure is used. at first, the soil profile is divided into substructures. then, the stiffness matrices of the substructures considered as the equivalent shear structures are assembled according to the finite element method. thereinafter, the stiffness matrices of the substructures are transformed into the modified finite element transfer matrices, which take part in the literature. finally, the system matrix is assembled using matrices of the substructures. the proposed method provides reduction in the size of the matrix. therefore, analysis time is remarkably reduced. at the end of the study, the accuracy of the method is presented by the examples. consequently, the proposed method offers a practical method for determination of the fundamental period of the soil.