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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.

Through the past few months, our world witnessed and is still suffering from several severe earthquakes in different places around the globe like Turkey, Syria, and Morocco. Therefore, the seismic activity domain grew the center of attention for researchers, engineers, and even regular people. The most significant topics in this field that must be taken into consideration are soil–structure interaction (SSI) and structure–soil–structure interaction (SSSI). The term SSI refers to the connection among structure, foundation, and soil while the term SSSI refers to the link among adjacent structures with the soil. Formerly, these subjects were not taken into account through the numerical and analytical methods utilized for the dynamic analysis of the seismic response of the structures (i.e., the effect of soil was ignored), and this matter led to disastrous costs that included loss of lives and properties. This article intends to offer an inclusive helpful knowledge of some significant factors that were not taken into consideration in the previous studies and can be utilized in the field of seismic analysis and design for minimizing the possible risks of earthquakes particularly the heavy ones by defining the SSSI behavior of adjacent structures due to these factors. To accomplish this goal, a sequence of seismic examinations via a shaking table system will be performed taking into consideration the impact of soil media. These tests will inspect the effect of the structure’s orientation and distance between them on the dynamic response of two close steel structures predicating on sand soil. The orientations selected here are of two types: the first one is parallel to direction of the earthquake wave and the second one is perpendicular to direction of the earthquake wave. Each orientation will contain three tests of three distances: close distance, medium distance, and far distance. Two novel small-scale multi-degrees of freedom steel models of three storeys are utilized in this study. Test results illustrated that the diversity of buildings orientation with distances has a significant effect on the SSSI behavior of the neighboring buildings. It is seen that the orientation perpendicular to the direction of the earthquake wave offered maximum impact on the dynamic responses at the far distance while the parallel orientation gave ultimate effect at the medium distance.

Rapid urbanization and land scarcity lead to the construction of multiple structures in proximity, supported on common soil media. This proximity increases soil stress, influencing the deformation characteristics of nearby footings. Hence, there is a need to investigate the effect of structure–soil–structure interaction (SSSI) on the footing settlement. In the present study, the effect of SSSI on the footing settlement of a three-storey building is investigated due to the presence of similar adjacent buildings arranged in various patterns (single adjacent building, side-by-side, L-shape, and inverted T-shape). The various interaction analyses are performed using finite element software ANSYS under gravity loading. The vertical and differential settlement of footings obtained from soil–structure interaction (SSI) and SSSI analyses are compared to evaluate the effect of SSSI under various adjacent building arrangements. The results indicate that in SSI case, inner footings show greater settlement compared to peripheral footings which causes high value of differential settlement between peripheral footings and those immediately adjacent to them. However, the presence of an adjacent structure in SSSI cases provides higher settlement in adjacent footings, which in turn reduces the differential settlement in these footings. Moreover, the SSSI effect on vertical settlement in SSSI (L-shaped) and SSSI (inverted T-shaped) is found to be more in corner footing located near to the adjacent buildings due to overlapping of soil stresses from two sides. The study quantifies the extent of settlement increase in various SSSI cases compared to SSI case, contributing valuable insights to mitigating potential settlement issues in densely developed areas.

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.

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.

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.

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.

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.