Simplified 1D Elastic Modeling of Duo-Pile Foundation System Incorporating the Interaction Mechanisms Prevailing under Lateral Loads

A Duo-pile foundation system can be an effective alternative where control of lateral deflection under eccentric lateral loads is stringent, e.g., in elevated highways and railways. Three-dimensional (3D) numerical analysis of such a system is more realistic but complicated and time-consuming. An equivalent one-dimensional (1D) analysis is desirable in practice, which is the focus of this article. First, a 3D model of Duo-pile has been analyzed in different scenarios to understand the interaction of piles and the connecting beam's role. Next, 3D and 1D models of various components and their interactions have been analyzed independently to find equivalent spring constants by comparing results. It includes pile-soil-pile interactions in longitudinal, transverse, and vertical directions. The Duo-pile system transfers moment in the transverse direction of the viaduct through the connecting beam, making its behavior different from the longitudinal direction. The proposed model covers the piles' reaction against the moment couple besides lateral and vertical pile interactions. The performance of the proposed 1D model of Duo-pile is assessed in different scenarios such as the presence of pier capping beam, soil heterogeneity, and soil nonlinearity under design loads. This model offers a simplified alternative with reasonable accuracy by realistically capturing the necessary interactions for serviceability conditions.