SIMPLIFIED SOLUTION FOR EVALUATING THE FOUNDATION INPUT MOTION OF EMBEDDED CAISSONS

This study presents the development of a simplified solution for evaluating the Foundation Input Motion of embedded caissons, considering the complex interaction between caisson and soil. Traditional methods often rely on computationally expensive numerical simulations. In contrast, the proposed solution provides a practical and accessible approach that maintains a balance between simplicity and accuracy, making it suitable for engineering applications. The proposed solution was derived from a parametric study performed using the finite difference method code FLAC3D, accounting for different values of the H/R ratio (where H is the height and R is the radius of the caisson), as well as the nonlinear response of the interacting soil. The caisson is modeled as a cylindrical element with the mechanical properties of concrete, while the soil is modeled using both a simple linear viscoelastic constitutive relationship and a nonlinear constitutive model (hysteretic model sig3). The proposed solution effectively captures the key dynamic behaviors with reasonable accuracy, making it a valuable tool for both preliminary design and for evaluating the seismic performance of existing structures. This approach provides an efficient and robust method for assessing caisson-supported structures, such as bridge piers, under seismic loading. The proposed solution was also compared with other methodologies available in the literature, demonstrating its effectiveness and applicability.