Elastic Stiffnesses of a Rigid Suction Caisson and Its Cylindrical Sidewall Shell

Abstract

A finite-element study is presented for the linear-elastic behavior of rigid suction caisson (bucket) foundations installed in either a homogeneous or nonhomogeneous Gibson soil stratum. Closed-form expressions are developed for the stiffnesses of the suction caisson in vertical (axisymmetric) and lateral (antisymmetric) loading, with emphasis on nonhomogeneous soil. The contribution of the cylindrical sidewall (shell) acting alone to the overall response of the system is also explored. It is then shown that for a shell length (depth of embedment) exceeding half of the caisson’s radius, in particular, the shell can offer essentially the same stiffness as the whole caisson.