A Lumped-Parameter Model for Soil-Pile-Foundation Systems Undergoing Horizontal-Rotational Motions Based on Multiobjective Optimization

Recently, soil-pile-structure interaction (SPSI) has played a vital role in analyzing the dynamic response of shear buildings in soft soil strata and seismically prone zones and assessing the vibration control of high-tech industrial structures with sensitive equipment. This study develops a generic lumped parameter (LP) model for three-dimensional (3D) simplified modeling of soil media and pile groups considering coupled horizontal and rocking motions. A multiobjective jellyfish search (MOJS) algorithm has been widely demonstrated as an efficient and effective algorithm for multiple objective problems; hence, it is adopted to determine the optimal parameters of the proposed LP model. In light of simplicity, soil strata and embedded piles are idealized by the proposed LP model at the pile head, and then the dynamic responses of the 3D soil-pile foundation (SPF) systems to externally forced loadings and seismic motions are easily obtained more straightforwardly with less computational effort. The proposed LP models are easily employed and incorporated into any structural FE programs to compute the time-history response of the SPF systems. The frequency-response curves and time-history responses of the SPF system computed by the proposed model perfectly fit with the complete system modeled in a specialized SPSI code for forced excitations and ground vibrations. Overall, the proposed LP model offers a straightforward approach yet produces an excellent result in analyzing the dynamic behavior of SPF systems to account for the SPSI effects. Assessing the dynamic response of SPSI systems effectively, it contributes to reducing serious injury and damage after earthquakes, as well as increasing the life-cycle of civil structures and high-tech industry systems.