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The effect of an earthquake on any structure is primarily determined by both its inherent properties and the surrounding environmental conditions. When seismic waves pass through different media, their characteristics and properties, such as amplitude, frequency content, and duration can change, thereby changing the seismic response of both soil and structures. The intensity and distribution of seismic waves can be influenced by several of key factors, including the local geology and stratigraphy, irregular topography, existence of man-made structures, and others. Relevant researches and studies have consistently emphasized the significance of the surrounding environment in seismic wave modification. Historical data also shows that similar types of earthquakes can result in varying degrees of damage depending on geographic location. Hence, a thorough understanding of the interaction between seismic waves and the surrounding environment is necessary for achieving precision in seismic design, risk assessment, and proper seismic mitigation strategies. An overview of contemporary research on seismic wave modification and the resulting interaction effects, presenting significant findings and analytical techniques related to phenomena such as soil-structure interaction (SSI) and its extended forms, including structure–soil–structure interaction (SSSI), soil–structure–cluster interaction (SSCI), and site–city interaction (SCI), is presented in this review article. The underlying mechanisms of these interactions are explored in this study and a detailed assessment of fundamental concepts, practical challenges, and methodologies for preventing and mitigating their effects in site-dependent settings is provided. Further, Topographic soil–structure interaction (TSSI) and topographic–structure–soil–structure interaction (TSSSI) are also discussed within a unified framework that considers the combined influence of topography and SSI extensions. This study focuses on the importance of the surrounding environment in influencing ground motion during earthquakes by identifying the complex interactions that affect the seismic response of both surface and underground structures. Some illustrative figures were generated with Microsoft Copilot and subsequently edited and validated by the authors.

Tuned mass dampers (TMDs) are widely implemented in many types of structures, such as tall buildings, wind turbines, towers, and bridges, to enhance the structural performance subjected to seismic and wind loading. In the present study, we aim to comprehensively investigate the effectiveness of TMD, by performing seismic vulnerability assessment of a 20-story steel building equipped with TMD and considering the soil-structure interaction (SSI) effects. A suite of high-fidelity three-dimensional nonlinear finite element simulations—in which nonlinear constitutive models are adopted for both structural components and soil, and Domain Reduction Method (DRM) and Perfectly Matched Layer (PML) are utilized to inject the seismic ground motions and represent the semi-infinite contents of the soil media, respectively—are conducted to obtain the structural responses. Finally, the performance of TMD is examined by comparing the fragility curves obtained under different conditions, i.e., with and without TMD, with and without SSI. It is observed that the TMD can notably decrease the structural demands, while the SSI effects can increase the fragility of structures, especially under strong earthquakes.

This study investigates the effects of adjacent deep excavation on the seismic performance of buildings. For that purpose, the numerical models are constructed for different buildings (i.e., 5-Story building and 15-Story building) considering the deep excavation-soil-structure interaction (ESSI) and soil-structure interaction (SSI). The results achieved from the ESSI and SSI systems are discussed and compared. Fully nonlinear numerical models with material, geometric, and contact nonlinearities are developed. Eleven earthquakes with different intensities, epicentral distances, significant durations, and frequency contents are applied to the models; and, the numerical results are given in terms of average records. The buildings are carefully designed and verified based on common design codes. The numerical modelling procedure of the deep excavation-soil system is validated using centrifuge test data. The comparisons between the ESSI and SSI systems are carried out in terms of accelerations, lateral displacements, inter-story drifts, story shear forces, and the nonlinear behavior of the soil medium under the buildings. The results show that it is necessary to consider the ESSI effect, and it might significantly change the seismic behavior of buildings adjacent to the deep excavations. The findings from this study can provide valuable recommendations for engineers to design buildings close to deep excavations under earthquakes.

Two structural configurations of the EuroProteas prototype structure, defining two test structures with different structural stiffness, were subjected to dynamic excitation to study the influence of soil-foundation-structure interaction effects on the recorded response. The first test structure was braced in all directions making a stiff structure frame based on soft ground. In contrast, we removed the bracing in the direction of loading in the second structure to significantly reduce its structural stiffness and the relative structure-to-soil stiffness ratio. Ambient noise measurements, free-vibration tests over a wide range of pull-out forces and forced-vibration experiments over a wide range of frequencies were included in the experimental series performed on both structures. The strong effects of the soil-foundation-structure interaction in the response of the stiff structure were expressed in the detected period elongation and the dominating rocking component which increased the radiation damping. The identified rocking stiffness was found to be frequency-dependent, in contrast to the lateral stiffness. On the contrary, the most significant proportion of the introduced energy was dissipated in the structural members of the second test structure, and the measured translation and rotation of the foundation were almost negligible.

A novel numerical methodology is presented to solve the dynamic response of railway bridges under the passage of running trains, considering soil–structure interaction. It is advantageous compared to alternative approaches because it permits, (i) consideration of complex geometries for the bridge and foundations, (ii) simulation of stratified soils, and, (iii) solving the train-bridge dynamic problem at minimal computational cost. The approach uses sub-structuring to split the problem into two coupled interaction problems: the soil–foundation, and the soil–foundation–bridge systems. In the former, the foundation and surrounding soil are discretized with Finite Elements (FE), and padded with Perfectly Match Layers to avoid boundary reflections. Considering this domain, the equivalent frequency dependent dynamic stiffness and damping characteristics of the soil–foundation system are computed. For the second sub-system, the dynamic response of the structure under railway traffic is computed using a FE model with spring and dashpot elements at the support locations, which have the equivalent properties determined using the first sub-system. This soil–foundation–bridge model is solved using complex modal superposition, considering the equivalent dynamic stiffness and damping of the soil–foundation corresponding to each natural frequency. The proposed approach is then validated using both experimental measurements and an alternative Finite Element–Boundary Element (FE–BE) methodology. A strong match is found and the results discussed.

Over the decades, various researchers have suggested that considering a structure fixed at the base predicts erroneous results in estimating the seismic response of soil–structure systems due to earthquake motions, potentially leading to faulty system designs. The magnitude of these errors may be attributed to variables such as soil type and modeling techniques. Improper modeling techniques are major factors contributing to erroneous responses of soil–structure systems. Selecting and implementing wave-transmitting boundaries are challenging tasks in finite element modeling techniques to simulate the infinite extent of soil and account for radiation damping in soil for solving soil–structure interaction (SSI) problems. This paper studies the effects of SSI and soil–structure–soil interaction (SSSI) on a four-storey steel structure with a raft foundation resting on soft semi-infinite soil. Here, the infinite domain of soil is simulated through an infinite element as a boundary condition after validating the modeling technique with experimental results found in the literature. The new modeling method, using ABAQUS, effectively handles soil–structure interaction (SSI) problems with acceptable accuracy, facilitating simulation of both SSI and SSSI scenarios for a four-storey steel structure. Using an infinite element (CIN3D8) in finite element method (FEM) analysis proves viable for SSI and SSSI simulations. Results show reduced storey drifts but varied floor shear forces across soil types (S1: a uniform soil system and S2: a two-layer soil system) compared to fixed base conditions. In SSSI analysis, higher storey levels experience increased drifts, while lower levels have decreased drifts compared to SSI scenarios. Base shear forces are consistently higher in SSSI analysis across all soil profiles, resulting in overall higher total floor displacements in both SSI and SSSI conditions compared to fixed base conditions.

Dynamic soil response and dynamic soil-structure interaction (DSSI) play an important role on the seismic response and distress of all engineering structures. The role of soil response and DSSI can be either beneficial or detrimental depending on the relationship between the dynamic characteristics of: (a) the seismic excitation(s) at the seismic bedrock (or at the rock-outcrop), (b) the soil layer(s) – if any, and (c) the overlying structure. On the other hand, the seismic response of a retaining wall is another DSSI problem, where the term \"structure\" is used to describe the retaining wall, while the term \"soil\" includes, apart from the retained soil layer(s), the soil layer(s) of the wall foundation. In urban environments the need for deep excavations usually requires the construction of temporal or even permanent retaining walls close to pre-existing structures, a fact that will probably have an impact on the dynamic soil response and/or the prevailing DSSI pattern. This positive or negative impact depends on the circumstances, while in the worst-case scenario this interaction may lead to single or double resonance phenomena. Under this perspective, the current study examines numerically the complex phenomenon of dynamic wall-soil-structure interaction (DWSSI). Additionally, an effective mitigation measure is examined, consisting of expanded polystyrene (EPS) blocks behind the retaining wall. This soft inclusion may offer a \"frequency tuning\" of the system that can potentially reduce the detrimental effects of DWSSI on the structure and/or the wall.

Validated 3D solid finite element (FE) models offer an accurate performance of buried pipelines at earthquake faults. However, it is common to use a beam–spring model for the design of buried pipelines, and all the design guidelines are fitted to this modeling approach. Therefore, this study has focused on (1) the improvement of modeling techniques in the beam–spring FE modeling approach for the reproduction of the realistic performance of buried pipelines, and (2) the determination of an appropriate damage criterion for buried pipelines in beam–spring FE models. For this paper, after the verification of FE models by pull-out and lateral sliding tests, buried pipeline performance was evaluated at a strike-slip fault crossing using nonlinear beam–spring FE models and nonlinear 3D solid FE models. Material nonlinearity, contact nonlinearity, and geometrical nonlinearity effects were considered in all analyses. Based on the results, pressure and shear forces caused by fault movement and pipeline deformation around the high curvature zone cause local confinement of the soil, and soil stiffness around the high curvature zone locally increases. This increases the soil–pipe interaction forces on pipelines in high curvature zones. The beam–spring models and design guidelines, because of the uniform assumption of the soil spring stiffness along the pipe, do not consider this phenomenon. Therefore, to prevent the underestimation of forces on the pipeline, it is recommended to consider local increases in soil spring stiffness around the high curvature zone in beam–spring models. Moreover, drastic increases in the strain responses of the pipeline in the beam–spring model is a good criterion for a damage evaluation of the pipeline.

In this paper the seismic response of linear behaving structures resting on compliant soil is addressed through the application of the Preisach formalism to capture the soil nonlinearities. The novel application of the Preisach model of hysteresis for nonlinear soil-structure interaction problems is explored through the study of the seismic response of a real structure. Through a harmonic balance procedure, furthermore, simplified nonlinear springs and dashpots are derived in closed form for a ready and accurate evaluation of the nonlinear soil-structure interaction response. The selected case study is the bell tower of the Messina Cathedral in Italy. The Bell Tower hosts the largest and most complex mechanical and astronomical clock in the world and it has been recently equipped by a permanent seismic monitoring system. A pertinent finite element (FE) model including the superstructure and the soil underneath, has been defined using authentic drawings and engineering design reports. The modal properties of the FE model have been compared with the experimental ones, identified from environmental noise recorded through the seismic monitoring system. Furthermore, the FE model has been validated by means of acceleration time histories recorded at different floors during two independent seismic events. A nonlinear incremental dynamic analysis of the Bell Tower has been also performed. The seismic response obtained by the complete FE analysis, has been compared with the proposed Preisach lumped parameter model, assembled with nonlinear springs and nonlinear dashpots. The results are well in agreement, offering an alternative promising strategy for the nonlinear soil-structure interaction studies.