Soil-structure Interaction Research Articles

Dynamic Analysis of a Periodic Soil‐Structure Interaction System to Reduce Ground Vibration

ABSTRACTMetamaterials have been developed to control electromagnetic, acoustic, and elastic waves, and can also be employed to manage seismic waves. As building clusters can significantly affect ground vibrations, this study extends the concept of metamaterials to evaluate a periodic soil‐structure interaction (SSI) system capable of reducing the ground vibrations caused by seismic waves. Using the theory of SSI with Floquet–Bloch theorem, a governing equation for a unit cell in a periodic SSI system is derived with effective earthquake forces from exterior sources. The dispersion relations of the periodic SSI system are subsequently obtained, and its frequency band gaps (FBGs) for surface waves are identified. Furthermore, the dynamic stiffness of rigid foundation, on which periodic superstructures are installed, and corresponding input motion are calculated when Rayleigh surface waves are incident to the system. The results indicated that foundation input motion is significantly reduced resulting in a reduction of structural response, and the dynamic displacements of the soil surface are significantly reduced owing to the FBGs within the SSI system. Finally, a parametric study is conducted to examine the effects of clear spacing between buildings, building height, and shear wave velocity in the underlying half‐space on SSI system behavior. The results confirm that the dynamic characteristics of a periodic SSI system depend on these factors and it must be designed accordingly.

A simplified soil-structure interaction model for load-settlement analysis of piles

The full skin friction and full end-bearing of a single pile are not mobilized at the same displacement while the conventional approach often oversimplifies by adding the skin friction to the end-bearing resistance as independent calculation steps. This paper presents a simplified interaction approach for the nonlinear load-settlement analysis of a single pile considering simultaneously the degradation of skin friction resistance and end-bearing resistance hardening under varying loads. The ability to estimate the load-settlement response of piles based on either needed loads or settlement is a special benefit of the proposed approach over existing methods. In addition, the proposed model is able to separate the skin friction resistance, end-bearing resistance and elastic compression at arbitrary settlement. The analytical method shown a satisfactory performance as compared to experimental results for three extensively studied field test situations. The suggested approach shows promise as a suitable solution for the design optimization as well as the preliminary analysis to organize a suitable loading test program. A parametric analysis is conducted to further examine the influence of various significant parameters related to the load-settlement response of piles.

Study on seismic response of a large-scale shield tunnel with an innovative loading device based on shaking table test

This paper presents the development of a large-scale tunnel model using an innovative loading device, which is then subjected to longitudinal seismic response analysis through a shaking table test. The loading device, designed to support the tunnel with springs, applies seismic loads from the shaking table and simulates the soil-structure interaction. Initially, the rationality and accuracy of the loading device were validated through numerical and analytical methods. Experimental results reveal that, under various seismic excitations, the acceleration response is significantly lower at the tunnel ends compared to the middle. The tensile strain response at the arch waist exhibits a U-shaped deformation along the longitudinal axis, while the compressive strain response exhibits a bending deformation with multiple inflection points. Furthermore, both tensile and compressive strain responses at the arch bottom show more pronounced bending deformations along the longitudinal direction. The findings indicate that the peak value of the input seismic excitation does not alter the deformation pattern of the tunnel. Within the longitudinal length L of the tunnel, the tensile zone reaches a maximum strain value εmax, whereas the compressive zone reaches a minimum strain value εmin. These experimental insights offer valuable references for the seismic design of tunnels.

Assessment of the influence of nonlinear soil effects on seismic response of RC structures with floating columns considering soil–structure interaction

Nonlinear dynamic properties of soil crucially influence structural responses during seismic events, highlighting the interdependence between soil and structural behavior. Incorporating soil–structure interaction (SSI) significantly increases structural vulnerability, especially in irregular conditions, compared to traditional fixed-base structures. Despite the emerging construction of reinforced concrete structures with floating columns in urban areas, their seismic performance, particularly when considering soil-structure interaction, remains largely unexplored. Therefore, this study aims to investigate the structural seismic response of mid-rise reinforcement concrete structures with and without floating columns situated on multilayered soil deposits, incorporating the effects of SSI. The nonlinearity of the soil materials was modeled using an isotropic hardening elastoplastic hysteretic constitutive model. A three-dimensional numerical investigation, employing finite element nonlinear time history analysis, was conducted to study seismic responses of structures under different configurations and base conditions. The results were presented as the ratio of structural responses with soil-structure interaction to fixed-base responses subjected to earthquake events. Structures with floating columns exhibited 1.43 times higher peak lateral storey displacement and 55% higher inter-storey drift ratio compared to those without, considering soil-structure interaction. The analysis results demonstrated a decrease in base shear values of up to 35% when accounting for SSI effects.

Seismic response of monopile-supported wind turbine systems: combination laws for kinematic and inertial interaction

The dynamic soil structure interaction imposes both kinematic and inertial interactions on monopile-supported wind turbines. The two effects can be calculated individually, but there is no clear guidance in the current design standard for combining them. A theoretical study using the finite element method to model a simplified single degree of freedom system has been conducted to analyse the phase relationship between the two effects and obtain the combination laws through parametric studies using the enhanced hysteresis control soil constitutive model. The results show that when the fundamental frequency of the soil is smaller than the superstructure, an in-phase relationship is observed. Monopile’s bending moments from the two loadings have different signums. Considering the inertial loading alone with an additional 5% modification is sufficient to capture the maximum bending moment and the profile. When the natural frequency of the soil is larger than the superstructure, an out-of-phase relationship is observed. The kinematic loading has a significant domination on the lower part of the pile. The worst-case scenario can be obtained when both loadings are combined using the simple addition rule. These findings enable engineers to combine two loadings in a simple manner, avoiding performing the lengthy dynamic time-history numerical analysis and facilitating an efficient design.

Hypoplastic Modeling of Soil–Structure Contact Surface Considering Initial Anisotropy and Roughness

The development of a constitutive model for soil–structure contact surfaces remains a pivotal area of research within the field of soil–structure interaction. Drawing from the Gudehus–Bauer sand hypoplasticity model, this paper employs a technique that reduces the stress tensor and strain rate tensor components to formulate a hypoplastic model tailored for sand–structure interfaces. To capture the influence of initial anisotropy, a deposition direction peak stress coefficient is incorporated; meanwhile, a friction parameter is introduced to address the surface roughness of the contact. Consequently, a comprehensive hypoplastic constitutive model is developed that takes into account both initial anisotropy and roughness. Comparative analysis with experimental data from soils on contact surfaces with diverse boundary conditions and levels of roughness indicates that the proposed model accurately forecasts shear test outcomes across various contact surfaces. Utilizing the finite element software ABAQUS 2021, an FRIC subroutine was developed, which, through simulating direct shear tests on sand–structure contact surfaces, has proven its efficacy in predicting the shear behavior of these interfaces.

Key Parameters to Model the Mutual Effects Between Base Isolation (BI) and Soil–Structure Interaction (SSI)

The mutual interaction between base isolation (BI) and soil–structure interaction (SSI) needs to be considered in design applications. In the literature, the key parameters that may affect such interaction have been rarely considered. Closed formulations for the assessment of the mutual role of BI and SSI have not been proposed yet. The paper aims to cover this gap by considering a 3DOF model to propose closed relationships with the most significant parameters (structural period, isolation ratio and shear wave velocity). The outcomes show that there are two different interactions. When soil deformability and structural stiffness are not significant, the isolation ratio may be used as a main parameter. However, when the foundation soil is particularly deformable and structures are significantly rigid, a more complex relationship needs to be considered. Parametric case studies have been performed with different structures, three isolation ratios and several soil conditions (soil A, B, C and D).

Nonlinear Analysis of Bridges Considering Soil–Structure Interaction and Travelling Wave Effects Under Combined Train and Near-Fault Seismic Loads

This paper presents a comprehensive method for analyzing prestressed concrete bridges subjected to multiple concurrent dynamic loads, incorporating soil–structure interaction (SSI) and seismic wave propagation effects. The study develops a comprehensive numerical framework that simultaneously accounts for traveling seismic waves, train-induced vibrations, and soil–foundation dynamics. Three-dimensional finite element modeling captures the complex interaction between the bridge structure, foundation system, and surrounding soil medium. The investigation considers the spatial variability of ground motion and its influence on the bridge’s dynamic response, particularly examining how different wave velocities and coherency patterns affect structural behavior. Advanced material constitutive models based on damage mechanics theory are implemented to represent both linear and non-linear structure responses under dynamic loading conditions. The analysis reveals that traditional simplified approaches, which neglect SSI, train, and seismic loading combinations, and traveling wave effects may significantly misestimate the structural demands. The results demonstrate how wave passage effects can either amplify or attenuate the combined response depending on the relationship between seismic wave velocity, the frequency content of the ground motion recordings, and the local soil conditions. These findings could contribute to the development of more reliable design methodologies for prestressed bridges in seismically active regions with significant railway traffic.

A Comparative Review of Dynamic Analysis Techniques for Elevated Water Tanks: Time History Method Versus Response Spectrum Method

This paper presents a comprehensive review of dynamic analysis techniques for elevated water tanks, with a specific focus on comparing the Time History Method (THM) and Response Spectrum Method (RSM). Drawing upon a wide range of literature sources, the review synthesizes existing research efforts dedicated to understanding structural behavior, seismic performance, bracing configurations, material considerations, and soil-structure interaction in the context of elevated water tanks. Despite the extensive body of literature in this field, a notable research gap exists in the systematic comparison of dynamic analysis techniques, particularly between THM and RSM. This paper highlights the need for a comparative review to evaluate the advantages, limitations, and applicability of THM and RSM for dynamic analysis of elevated water tanks, providing valuable guidance for engineers and researchers in selecting the most suitable method based on project requirements and constraints.

Mechanisms of Vertical and Horizontal Seismic Motions on Foundation Liquefaction Response and Uplift of Subway Stations

ABSTRACT Historical earthquake-induced damage and studies have shown that the impact of vertical earthquake motions on sand liquefaction cannot be ignored in liquefiable sites with underground structures. Therefore, this study performed a finite element-finite difference (FE-FD) coupling numerical method to compare the influence of different seismic component excitations (vertical, horizontal, and bidirectional) on sand liquefaction with and without subway stations and to further explore the uplift mechanism of the subway station under vertical earthquake motion. The results revealed that the liquefaction response of the foundation soil is much different in the model with and without the subway station. In a liquefiable site with a subway station, the vertical seismic component may also trigger soil liquefaction due to soil structure interaction, while in the unstructured site, it cannot trigger liquefaction. The vertical seismic component will aggravate the degree of liquefaction and horizontal acceleration response of soil near subway stations, and the extent of this influence decreases with the increase of horizontal distance between the soil and the side wall of the subway station. In addition, the influence of vertical earthquake motions on the uplift of subway stations is related to seismic wave characteristics and the value of Arias intensity. The mechanism of the effect of vertical earthquake motion on the uplift of subway stations is to reduce friction between structure and soil and increase the flow deformation of the soil.

Alternative Design Approach Addressing High Shear Demands in Rock Sockets

It is a common strategy to “socket” drilled shafts into rock to develop lateral or axial capacity where overburden soils are shallow and/or relatively weak compared with the underlying rock formation. Methods of numerically modeling soil-structure interaction using discrete, nonlinear springs representing soil response as a function of pile discplacement (p-y methods) demonstrate shear forces near the top of the rock sockets that are significantly larger than the applied forces to the drilled shaft. The amplification effect has been shown to decrease with decreasing rock quality. The ensuing shear forces can often significantly exceed the structural capacity of rock sockets as calculated using traditional sectional methods with practical reinforcing ratios. Considering the mechanics and geometric characteristics of load transfer through the rock socket into the supporting geomaterial, it is apparent these elements should be characterized as D-regions for which an STM approach is an appropriate tool for assessing the rock socket structural capacity. Such an approach has been demonstrated to yield drilled shaft and rock socket sections that are more economical and constructable.

Seismic Response of Ground Penetrating Shield Tunnels Under Lateral Harmonic Excitations: Insights From Shaking Table Test

ABSTRACTThe ground penetrating shield tunnel (GPST) method offers a streamlined approach to tunnel construction in soft ground with limited open‐cut excavation. To explore the seismic response of GPST linings, a series of large‐scale shaking table tests have been conducted, including a variety of seismic excitations. This paper focuses on lateral harmonic excitation. The model tunnel spans a total length of 7.7 m, with the embedment depth ranging from −0.5 to 0.5 times its diameter. The design and fabrication of the model tunnel are presented, including the segmental lining, along with circumferential and longitudinal joints. The soil was modeled with artificial synthetic soil, aiming to simulate the static and dynamic characteristics of the prototype soil. Its composition was adjusted and verified through element tests. The experimental results provide insights into the seismic response of the soil–tunnel system, the ovaling deformation of the segmental lining, as well as the response of the joints between lining segments. The results reveal a strong influence of embedment on tunnel seismic response. The reduction of tunnel embedment leads to a significant increase in lining accelerations and a phase difference, resulting in a “whiplash” effect. In contrast, the ovaling deformation of the lining and the joint apertures decrease with the reduction of embedment. In the sections of the tunnel that are fully embedded, both the acceleration and deformation response of the lining are governed by soil–structure interaction (SSI). A pronounced whiplash effect is observed in the sections of the tunnel that are not fully embedded, due to the absence of soil confinement. The presented experimental results offer valuable insights into the seismic response of GPSTs, which can be of crucial importance for their seismic design.

Seismic Analysis of Irregular Building Subjected to Pounding

Earthquakes have always been a source of great devastation for humanity. With the fast growth of metropolitan cities, land limitation has become a critical issue, resulting in the construction of high-rise buildings very close to each other. Such buildings are prone to seismic pounding. During earthquake, the buildings vibrate out of phase and at rest separation is deficient to accommodate their relative motions. It can be prevented by ensuring safe separation distances between buildings. However, achieving the necessary separations is often not feasible in metropolitan areas due to high land values and limited land availability. Different combinations of 12-storey and 8-storey buildings with varying plan irregularities were considered for the analytical study using ETABS software. The pounding effect depends on building characteristics, ground motion characteristics and soil structure interaction. The parameters like displacement, impact force, and storey shear were determined.

Research on the Mechanism of Load Transfer Structures in the Construction Process of “Internal Support—Large Block” Prefabricated Subway Stations

In the context of rising global temperatures, countries around the world are increasingly tailoring their own “carbon neutrality” plans. China has also formulated its “dual-carbon” goals, and the construction industry is gradually transitioning towards prefabrication to reduce carbon emissions. This paper uses the Sha Pu Station of Shenzhen’s Metro Line 12 as a case study by which to explore the effects and mechanisms of the load transfer structure during the assembly process of prefabricated subway stations. A three-dimensional finite element model considering soil–structure interaction was established using MIDAS GTS NX finite element software, 2018 version. The internal forces, stresses, and deformations of the station structure were compared under two scenarios—with and without the load transfer structure—using a control variable method. The research results indicate that the load transfer structure effectively reduces shear forces, bending moments, and stresses in the station structure; limits lateral displacements during the assembly process; and effectively concentrates the maximum stresses during construction at the location of the load transfer structure, thereby preventing stress concentration phenomena and enhancing the overall stability of the station structure. This study elucidates the role and effectiveness of the load transfer structure during the assembly of prefabricated components in subway stations, providing a reference for the construction of similar prefabricated metro stations.

Impacts of Transition Piece Designs on the Resilience of Large Offshore Wind Turbines Subject to Combined Earthquake, Wind and Wave Loads and Soil‐Structure Interaction

ABSTRACTThe urgent global drive to mitigate greenhouse gas emissions has significantly boosted renewable energy production, notably expanding offshore wind energy across the globe. With the technological evolution enabling higher‐capacity turbines on larger foundations, these installations are increasingly situated in earthquake‐prone areas, underscoring the critical need to ensure their seismic resilience as they become a pivotal component of the global energy infrastructure. This study scrutinises the dynamic behaviour of a 15 MW offshore wind turbine (OWT) under concurrent earthquake, wind and wave loads, focusing on the performance of the ultra‐high‐strength cementitious grout that bonds the monopile to the transition piece. Employing LS DYNA for numerical simulations, we explored the seismic responses of four OWT designs with diverse transition piece cone angles, incorporating nonlinear soil springs to model soil‐structure interactions (SSIs) and conducting a site response analysis (SRA) to account for local site effects on ground motion amplification. Our findings reveal that transition pieces with larger cone angles exhibit substantially enhanced stress distribution and resistance to grout damage, evidenced by decreased ovalisation in the coned sections of the transition piece and monopile, and improved bending flexibility. The observed disparities in damage across different cone angles highlight shortcomings in current design guidelines pertaining to the prediction of grout stresses in conical transition piece designs, with the current code‐specified calculations predicting higher stresses for transition piece designs with larger cone angles. This study also highlights the code's limitations when accounting for grout damage induced by stress concentrations in the grouted connections under seismic dynamic loading conditions. The results of the study demonstrate the need for refinement of these guidelines to improve the seismic robustness of OWTs, thereby contributing to the resilience of renewable energy infrastructure against earthquake‐induced disruptions.

Effect of adjacent structures on footing settlement for different multi-building arrangements

Abstract 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.

Evaluation of the influence of masonry walls on the soil-structure interaction mechanism through computational modeling of a reinforced concrete building

The present study aims to investigate the influence of masonry walls on the soil-structure interaction mechanism for a reinforced concrete building. For this purpose, two finite element models are developed using the SAP2000 program, namely: (i) a three-dimensional model without masonry walls and (ii) a three-dimensional model with discretized masonry walls. The latter model, closer to reality, provides greater stiffness in the superstructure. In the analysis, both fixed supports and spring supports are employed. The results of the model with discretized masonry walls are similar to those of the model without masonry walls, i.e., when considering the soil-structure interaction, a redistribution of forces in the structural elements was observed. Peripheral columns showed an increase in demand while the central column showed a reduction in demand. There was a tendency for uniformization of differential settlements especially in the model with discretized masonry walls, and also an increase in positive bending moments in the spans and negative bending moments in the peripheral supports of the central beam at the ground level. That is, if the structural design does not consider settlements (as in the case of a design without soil-structure interaction), settlements can lead to localized plasticizations in the beams. Thus, the importance of refined models is perceived, and also, in cases where settlements are significant, the effect of soil-structure interaction is relevant in the design, not only of foundations, but also of the structure.

Soil-structure interaction effects on modal analysis of a 3D reticulated structure supporting plane rectangular shells

This paper aims to verify the interference of soil-structure interaction (SSI) on the natural frequencies and on the respective vibration modes of a 3D reticulated structure supporting plane rectangular shells. This is done through a computational linear elastic 3D finite element model using EulerBernoulli frame elements, biquadratic Lagrangian thin shell elements and elastic translation springs for the soil at columns bases (representing pile embedded length). A convergence analysis is performed to determine the maximum mesh size and mass participation factors are measured to establish the number of considered vibration modes. Chosen elastic spring coefficients are extracted using polynomial linear regression applied to the results of experimental compressive and horizontal load tests of steel piles embedded in a silty clay soil. Using these parameters, nine models are processed via an eigen solver and obtained frequencies and some mode shapes are presented. It is found that, for the adopted approach and for the evaluated structure, there are not significant changes in modal response induced by SSI, being the mass distribution more important than soil stiffness in this case. Despite the results, this study indicates the need of further investigation to provide better measures about the interference of SSI on modal response of structures as the one analyzed in this research.

Numerical modelling of a soil structure interaction for a torpedo base conductor in a petroleum well under an extreme lateral load

This work aims to compare the performance, regarding the soil structure interaction, of a torpedo base conductor and a jetted conductor, considering a drilling rig drift-off scenario. This can be considered an extreme load scenario and the results will be shown for lateral loads coming from the interaction between the wellhead and the drilling rig, drilling riser and BOP.A complete 3D CAD model of the Torpedo Base Conductor was created and the soil was also modelled with 3D elements. Based on previous references, the selected 3D soil element was the Drucker-Prager constitutive model (Costa, 2008, Aysen, 2016 and Sanomia, 2016). Notably, the Drucker-Prager model accounts for non-homogeneous soil, meaning that the material properties vary with depth according to its undrained shear strength profile.The final results show the behavior of soil under lateral loads for both the torpedo base and the jetted conductor, as well as the structural response. The final conclusion is that the torpedo base has a better performance under lateral loads than the jetted conductor and can be considered a good well foundation solution to mitigate problems associated with interventions with dynamic position drilling rigs in shallower water depth.

Optimal Design of Pile Caps considering Soil Structures Iteration

This study presents a formulation for the optimum design of pile caps considering the soil structure interaction. To solve the optimization problem, the Bonobo algorithm is used. This algorithm was developed based on the social behavior of bonobos and is implemented for the design of the pile caps and the piles. The objective function considers the CO2 emissions and the pile cap final costs related to the materials used for its execution. The Brazilian standard impositions, and the criteria for determining the optimal dimensions of piles are the considered problem constraints. Comparative analyses are developed between the optimal solution against the proposed by structural design offices, and results proposed in the literature.