Soil-structure Interaction Model Research Articles

A review of graphical user interfaces of OpenSees software framework

Seismic vulnerability assessment is crucial for evaluating the resilience of structures. OpenSees, an open-access and versatile tool, plays a pivotal role in accurately simulating the complex behavior of structures subjected to seismic loads. However, lacking a built-in graphical user interface (GUI) is one of the limitations of OpenSees that can hinder usability and accessibility. Moreover, users must rely on command-line inputs and scripts for interaction, potentially limiting its adoption by non-programmers. To address this, several GUIs were designed as pre- and post-processor for OpenSees. In this study, 15 GUIs were categorized as open access or commercial. The functionalities and features of the GUIs, such as open-source nature, three-dimensional (3D) modeling and visualization capabilities, automation of incremental dynamic analysis (IDA), and simplification of soil-structure interaction (SSI) modeling, were examined. Note that certain GUIs were introduced with a focus on modeling and analysis of specific structures that were reviewed in this study. This mini-review aims to guide OpenSees users in choosing an appropriate GUI for their projects and support developers in improving existing GUI functionality or creating advanced GUIs that comprehensively cater to users’ needs.

Advanced numerical modelling of the nonlinear mechanical behaviour of a laterally loaded pile embedded in stiff unsaturated clay

Capturing and understanding the ultimate limit state behaviour of reinforced concrete piles embedded in soil requires the use of advanced tools or the performance of expensive tests. An experiment was performed where reinforced concrete piles embedded in a stiff unsaturated clay profile were load-tested on-site. However, even though in-situ experiments can provide engineers with valuable insight, their cost and time limitations come with restrictions, especially when dealing with a parametric investigation on the soil's material properties, the size of the piles, or the piles' material properties. The objective of this research work was to numerically model the nonlinear mechanical behaviour of laterally loaded full-scale piles through detailed 3D modelling, and perform an in-depth parametric investigation to provide answers to unknown factors that the actual physical experiment could not answer. Furthermore, this work serves as a pilot project that will be used to pave the way in developing multiple soil-structure interaction models that will be used to generate a dataset that helps the creation of predictive models through machine learning algorithms. For the needs of this research work, the reinforced concrete piles were discretised with 8-noded isoparametric hexahedral elements that accounted for cracking through the smeared crack approach. Steel reinforcement bars and stirrups were simulated as embedded rebar elements, while the soil domain was also discretised through 8-noded hexahedral elements. Most of the required material properties assumed during the nonlinear analyses were defined according to relevant laboratory experiments. According to the numerical investigation, it was found that the proposed numerical model has the ability to reproduce the experimental results with high accuracy, while providing in-depth insight on the failure mechanisms for both the soil and reinforced concrete domains.

Soil-structure-interaction effects on the seismic performance of a masonry building under geothermal power plants induced earthquakes

The earthquakes caused by the geothermal power plant (GPP) operation are a new phenomenon observed in recent decades. Low-to-moderate magnitude events with a high recurrence rate. This research focuses on the evaluation of the impact of modeling soil medium and its interaction with a masonry building on the overall performance of the whole system. In this regard, a typical masonry building in Germany is considered. A set of 11 ground motion records of induced earthquakes by the GPP activity is adopted. Two separate detailed 3D nonlinear structural models of the building are developed. In the first one, the base support condition of the structure is assumed to be fixed, while in the second case, the building, the underlying soil medium, and their interaction are simulated in an integrated model. By obtaining their responses to the earthquakes through the time history analysis approach, the structural damage level, as well as the comfort level of the occupants of the building, are evaluated. The outcomes show that the structural damage remains at a low level in both cases; however, consideration of soil medium slightly intensifies the damage level. Furthermore, in terms of occupant comfort, humans will suffer from significant disruption, especially when the effect of soil-structure interaction (SSI) has been taken into account. Finally, a relationship between the comfort level of the occupants and the intensity measure of the earthquakes is developed for both fixed base and SSI models.

Comparison of Pile–Soil–Structure Interaction Modeling Techniques for A 10-MW Large-Scale Monopile Wind Turbine Model Under Wind and Wave Conditions

Comparison of Pile–Soil–Structure Interaction Modeling Techniques for A 10-MW Large-Scale Monopile Wind Turbine Model Under Wind and Wave Conditions

Physical and numerical modeling of seismic soil-structure interaction of prefabricated subway station structure

Physical and numerical studies were conducted to explore the seismic performance characteristics of multi-story and multi-span prefabricated subway station structures, and to identify its weak parts and damage mode during earthquakes. A two-story three-span prefabricated subway station structure was designed and fabricated with a scale ratio of 1:10 and was subjected to a static pushover test that simulated the soil-structure interaction. The test results were interpreted to determine the horizontal resistance - interstory displacement capacity curve of the station, and the interstory displacement ratio (IDR) limit values under each seismic performance state. The experimental results revealed that the upper layer of the prefabricated subway station structure was more severely damaged than to the lower layer, and that the column ends of the upper layer were the weakest parts of the structure in terms of seismic resistance. The splicing joints were generally reliable, but the side wall-middle span splicing joint showed visible cracks. Furthermore, a finite element model was established based on the physical test configuration and was utilized to analyze the pushover tests. The numerical results indicated that the vertical load significantly accelerates the prefabricated subway station to reach the peak point and limit point of its horizontal bearing capacity. The IDR value of subway station seismic performance level 4 determined by the bearing capacity curve of the column was 30% lower than the IDR value obtained by the structural bearing capacity curve.

Nonlinear time-domain soil-structure interaction analysis of a mid-rise building benchmarked against earthquake recordings: A case study of the BRI's annex building

Performing soil-structure interaction (SSI) analysis under strong shaking scenarios using the direct method is becoming more prevalent in engineering practice. However, given the pronounced nonlinearity in soil, structure, and foundation response, the robustness of current methodologies is open to question, and benchmarking these methodologies against instrumented case histories is needed to identify the strengths and weaknesses in the approach. In this study, a three-dimensional (3D) Nonlinear (NL) Soil-Structure Interaction (SSI) analysis methodology in the time-domain code LS-DYNA is benchmarked against the actual recordings for a mid-rise building. The well-instrumented Building Research Institute (BRI) Annex Building (ANX) in Tsukuba City northeast of Tokyo, Japan, which features an adjacent free-field geotechnical downhole array, is used for this case study. A Finite Element (FE) three-dimensional 3D SSI model of the site, including the BRI ANX building, that considers both material and geometric nonlinearities is first developed. Two events are applied to the model: the 2011 Tohoku-Oki earthquake main shock (Mw9.1), referred to as the Great East Japan Earthquake (GEJE), and the 2002 Southern Ibaraki Prefecture earthquake (Mw4.9), selected from the BRI strong motion network due to the relatively wide amplitudes recorded at the site. The former event induced maximum shear strains in the soil of 1.6%, while the latter event induced maximum shear strains of 0.08%. For both horizontal and vertical components of shakings, the predicted response of the structure and adjacent free-field downhole array are compared with the corresponding recordings. The results show that the structural response is significantly affected by the accuracy of the predicted free-field ground surface response, especially at the structural fundamental period as opposed to the site period. In addition, results indicate that the fixed-base and flexible-base structural models’ responses are substantially different, mainly attributed to the SSI effects that cannot be captured in the fixed-base model. Finally, a comprehensive discussion on the minimum amount of data required to adequately capture nonlinear structural response using the proposed SSI methodology is provided in this case study.

Influence of Soil Flexibility on Seismic Behavior of RC Buildings with Shear Wall

The seismic response of a structure is very complex owing to the behavior of soils during an earthquake. The importance of including the soil–structure interaction (SSI) effect in building frame analysis is quickly recognized, but the modeling of SSI is complicated. The present paper investigates the seismic response of a RC building incorporating soil–structure interaction. The research focuses on clayey soil conditions in situ, taking into account soft, medium, and hard soil. The SSI effect is accounted for by using a point spring element and a fixed support condition. For the study, a RC ground (G)+10-story building with a basement is considered with L-shape (L-SW) and T-shape (T-SW) shear walls resting on a raft foundation. To comprehend the different circumstances of the soil on the structure for comparison study, the responses of some parameters such as story drift, story displacement, and base shear are obtained. The findings of the study show that including SSI effects in the seismic design of multistory buildings is critical because it can result in a significant reduction in controlling design forces without compromising the structure’s safety. Moreover, assuming a fixed base can lead to a high overestimation of the structure design forces and seismic response. The aim of the present study is to obtain the behavior of the RC building under different soil conditions considering two types of shear walls.

Integration of Building Information Modeling Interoperability into Nonlinear Finite Element Analysis of Bridge Substructures

Acceptance of building information modeling (BIM) throughout the bridge industry is widely recognized as inevitable. However, while adoption of BIM technologies has proliferated throughout the building industry, advances pertaining to BIM for bridges and other structures remain underway. The present study aims to increase the potential for integrating BIM processes into software packages that possess capabilities for nonlinear finite element analysis (FEA) of bridge substructures. Moreover, the present study is intended to galvanize stakeholders within the area of soil–structure interaction (SSI) modeling and analysis to more effectively participate in interoperability workflows as part of bridge design. A proof-of-concept exporter tool was formulated in a modular manner to robustly export finite element model data stored in a selected SSI analysis package into the Industry Foundation Classes (IFC) standard, with the IFC standard chosen as the target schema owing to its widespread usage in the construction industry. The ability of the exporter tool to—with fidelity—convert a model from the selected analysis software to the IFC standard is showcased through an illustrative case study. In carrying out the case study, collections of geotechnical modeling parameters were identified that, while being common to numerous nonlinear SSI analysis packages, are not present in the existing IFC schema. Inclusion of these parameters in the IFC schema is proposed, serving to: 1) lower the barrier for entry of SSI modeling and analysis stakeholders to take part in interoperability processes and 2) encourage adoption of novel BIM processes in the bridge industry.

Influence of Soil–Structure Interaction Models on the Dynamic Responses of An Offshore Wind Turbine Under Environmental Loads

Influence of Soil–Structure Interaction Models on the Dynamic Responses of An Offshore Wind Turbine Under Environmental Loads

Influence of soil-structure interaction modeling on the behavior of multi-story plane steel frames with shallow footing foundations

Traditionally, structural analysis is based on the hypothesis that supports are indeslocable due to simplicity. However, the conventional design in which settlements of foundation elements are disregarded can lead to physical results that are incompatible with reality. This work aims to analyze the influence of the consideration of soil-structure interaction (SSI) on the responses of steel structural elements obtained by a static second order analysis. Furthermore, it is evaluated the responses obtained by different types of procedures for the consideration of soil stiffness in the structural analysis. Solid elements considering linearly elastic material parameters and spring elements based on the Winkler theory are employed. The analyses were performed with the commercial software SAP2000. Plane steel frames models were analyzed, either considering conventional supports or taking into account the soil-structure interaction. Shallow footing foundations are considered. Three frames with the same characteristics, but with a different number of floors were analyzed, showing the influence of the height increase and the building stiffness on the SSI results. It has been shown that the consideration of the effects of soil-structure interaction on structural analysis of buildings can have a significant influence on the stress distribution, displacements and structural behavior. In addition, it is concluded that the structural capacity of steel frames can be affected by the type of support adopted and by changes on the way the model considers soil deformation.

Soil-structure pile foundation interaction model due to lateral loading

Experimental research on piles, by models and physical tests on a laboratory scale, using materials and sizes that are different from the prototypes. The model is designed, treated, and interpreted the results of observing the response based on similarity using Model theory, but the soil sample cannot be modeled with model theory, giving rise to doubts similarity of the research. This study was conducted to examine the effect of pile-soil interaction on several views of the elastic modulus of the soil due to lateral loads. Laboratory model pile foundations are laterally loaded, on soil samples in a test box. The deflection of the pile foundation is analyzed based on the use of linear, layered, and non-linear modulus of elasticity. A non-linear simulation of the Winkler model with a spring along the depth of the pile was carried out to calibrate the horizontal deflection of the laboratory experimental model. The results showed that the Winkler model's modulus of elasticity was approximately 40% of the pile length, and the non-linear difference between the Winkler and laboratory models was 10.77%, comparisons can be conclusive about the need for similar research on lateral loading of laboratory model piles. The analysis also noted that the surface deflection was determined by winkler’s model elastic modulus analysis with an excess of about 12% to 14% in the first 10% of the pile length.

The numerical simulation of soil–structure interaction containing sustainable materials

As a result of urban transformation activities, natural disasters, regional and global wars, billions of tonnes of waste concrete occur. Therefore, the remediation process of waste concrete is one of the critical research topics of recent years. The sustainability concept provides a primary bridge between the demand for natural concrete material and the remediation process of waste concrete. Recycled aggregate and recycled concrete aggregate, which may be named sustainable materials, are obtained by the recycling process of waste concrete. Many experimental and numerical studies have been conducted in recent years to show that this sustainable material is an alternative product to natural aggregate. In this study, a comprehensive numerical simulation of foundation beams resting on soils incorporating conventional and sustainable materials has been performed. The foundation beams considered include some with conventional concrete properties and some with sustainable concrete properties. Additionally, the material conditions of soils are assessed, using six different mixed recycled aggregates as filling material. Based on the numerical simulation, the deflection, rotation, bending moment, shear force and spring force capacities of conventional and sustainable foundation beams resting on soils exhibited slightly different behaviour depending on the recycled concrete aggregate and mixed recycled aggregate ratios. Finally, comparing the numerical simulation results of soil–structural interaction members incorporating conventional and sustainable materials indicated that the soil–structure interaction modeling process applied to conventional foundation beams resting on soils is also valid for sustainable members.

Wind and soil model influences on the uncertainty in fatigue of monopile supported wind turbines

Several alternative engineering models are available for the use in analysis of offshore wind turbines. However, it is not always clear which of the models will yield the most accurate or sufficiently conservative results. This paper investigates the effect of using two alternative soil-structure interaction models and two wind coherence models. The focus is on assessing how these modelling choices influence the predicted long-term fatigue damage in the support structure. The two soil models are a macro-element model and a p-y-curve model with Rayleigh damping. This gives differences in both the damping and stiffness properties of the turbine model. The differences between the two soil models tend to decrease as the turbine size increases. The wind coherence models considered are the Kaimal spectrum with exponential coherence and the Mann uniform shear turbulence model. The Kaimal model predicts the highest response at low frequencies, while the Mann model gives the highest response predictions at higher frequencies. Which turbulence model predicts the highest long-term fatigue damage is then determined by the natural frequencies, rotor and blade passing frequencies of the different turbines.

Three-Dimensional Modeling of Soil-Structure Interaction for a Bridge Founded on Caissons under Seismic Conditions

In recent years, the urgent need to increase the safety standards of viaducts and bridges—under static and dynamic loading conditions—has required the development of advanced modeling approaches able to accurately predict the expected behavior of such infrastructures in a reliable manner. This paper presents a comparison between the adoption of a simplified modeling approach, widely used in the current practice, where the response of the structural system neglects the effects of the soil-structure interaction (SSI) phenomenon (considering the base of the structure fixed at the ground surface) and a rigorous modeling approach that considers the full 3D problem with all the components of the system (superstructure, foundation, and soil), through a finite element model. The pier of a real-world viaduct in central Italy was considered, with the aim of starting from a specific case study with foundation characteristics that are frequently found in viaducts in Italy, to obtain results that can be generalized to a wide range of similar types. Its behavior was evaluated both in the dynamic range of small oscillations and in the field of the seismic response to low and strong motion events. The results show that, in terms of seismic demand, the fixed-based model appears more conservative, but it significantly underestimates both elastic and residual displacements and rotations

Numerical investigation of the contribution of the soil-structure interaction effects to the seismic performance and the losses of RC buildings

Seismic vulnerability and loss analyses of buildings are usually estimated under the fixed-based condition, omitting the soil-structure interaction (SSI) effects. However, according to the literature and the seismic damage due to past events, mid-to high-rise buildings located on soft soils can present a worse seismic performance. This manuscript aims to investigate whether the SSI effects affect the seismic performance and the losses of reinforced concrete (RC) buildings. To do so, a real 5-storey RC building has been selected as the case study. It was built prior to restrictive Spanish seismic codes. The building was constructed over soft alluvial strata and it has a shallow foundation. The area is characterised by a moderate seismic hazard. Nonlinear static analysis (NLSA) and incremental dynamic analysis (IDA) have been performed to assess the seismic behaviour and the losses expected of the case study building. The calculations have been done in the OpenSees finite-element framework. The direct method has been used to model the SSI. The results have been obtained for the fixed-base and for the SSI models. The numerical outcomes have shown the remarkable effect of the SSI on the fragility and on the performance of these structures. It has been observed that the severe damage expected can be worsened by up to 38% if SSI is taken into account. Additionally, the soft-storey mechanism at the ground floor concentrates all the damage expected, showing that this is the most seismic vulnerable part of the building (owing to higher interstorey-drift ratios and peak floor acceleration values). The losses expected derived for structural and non-structural components have been 140% higher if the SSI is considered.

Performance of an RC building under seismic and tsunami actions in sequence via nonlinear dynamic analysis including soil-structure interaction

This research presents a methodology to study the behavior of buildings subjected to seismic and tsunami loading in sequence, considering soil structure interaction effects through a complete dynamic analysis. The case-study building is an RC frame, which is assumed to be located in a coastal city in Chile, and built on sandy soil. A 3D Soil-Structure Interaction (SSI) model, including the non-linear behavior of both the structure and the soil using finite element method (FEM) was presented. Synthetic seismic ground motion records and tsunami inundation time histories were generated, consistent with the same earthquake source. Building performance was first assessed considering the SSI model for each hazard separately and compared to a Fixed Base (FB) model. Then, the SSI model was subjected to seismic and tsunami loading in sequence. Engineering Demand Parameters (EDPs) of roof displacement, interstory drift ratio (IDR) and reinforcement strain in beams and columns were analyzed. These EDPs presented a larger response to the tsunami when the response to the previous earthquake was larger. Finally, two vertical evacuation building scenarios were studied: the location of the refugees and the effect of an aftershock occurring simultaneously with the tsunami inundation. Results showed that the location of the refugees did not generate significant differences in the building response, and the aftershock increased the response only when it coincided with the maximum tsunami force.

Seismic response of shield tunnel structure embedded in soil deposit with liquefiable interlayer

Shield tunnels are widely in used urban areas and could be constructed in fully or partially liquefiable soil deposits and are thus susceptible to damage during earthquake events. In this paper, a two-dimensional saturated soil-structure dynamic interaction model is developed for shield tunnel lining structures. The model accounts for the nonlinear mechanical behaviors of the shield tunnel segments and joints. It also accounts for the soil nonlinear behavior by employing plasticity models (i.e., PM4Sand and PM4silt for sand and plastic silt/clay, respectively). The seismic response of the shield tunnel structure in soil deposit with liquefiable interlayer as well as the interaction mechanism between the liquefiable soil layer and the tunnel are investigated. The obtained results demonstrate that the sand dilatancy and cyclic mobility behaviors under undrained loading conditions govern the seismic site response and that the presence of tunnel structure changes the site acceleration response and degree of soil liquefaction. It is also found that internal forces and deformations of the tunnel segment joint around the foot and shoulder are significantly larger than that in the rest of joint positions. Therefore, particular attention should be paid to potential damage of joint bolts around the foot and shoulder in a liquefiable soil deposit.

An equivalent beam approach for assessing tunnelling-induced distortions of frames with infills

This paper presents an approach to evaluate the response of low- and medium-rise frames with continuous foundations, either with or without infills, to tunnelling employing an equivalent beam with a behaviour dominated by shear deformations. Simplified soil-structure interaction models, consisting of a beam resting on an elastic continuum half-space, are compared against advanced three-dimensional analyses in which the tunnel, the soil, and the building are explicitly modelled. In the simplified approach, the frame is schematised as a Timoshenko beam and reliable procedures to estimate both bending and shear stiffness are discussed. In the refined modelling strategy, an advanced elastoplastic constitute law is employed, capable of reproducing fairly well the soil response to the excavation for increasing values of volume loss, while the full geometry of the structure is considered. First, the results of the proposed numerical approaches are compared in terms of tunnelling-induced foundation displacements, bay deformations and maximum tensile strains in the infills. Then, for the infill panels, the reliability of estimating the maximum tensile strain from the angular distortion of the frame bays is assessed. Finally, a meta-model is proposed to predict the maximum angular distortion based on greenfield settlements, eccentricity, and relative soil-structure stiffness.

Improved soil–structure interaction model considering time-lag effect

An important aspect of soil– structure interaction analysis is establishing a high-precision conversion relationship between the dynamic impedance in the frequency domain and impulse response function in the time domain. Accordingly, an improved Nakamura model was developed in this study to convert dynamic impedance to an impulse response function. The causes and distribution rules of repeated phase angles were investigated based on the traveling time-lag effect, rendering the improved method more robust. In addition, the impulse response function and interaction force can achieve high fitting accuracy by stripping the singular term from the conventional term. In this study, the time-domain impulse response function and interaction force were derived based on the force–displacement relationship. Further, the accuracy and stability of the improved method were verified using a semi-infinite bar on an elastic foundation. Then, the effects of frequency interval, maximum frequency, and shape of the coefficient matrix on the impulse response function and interaction force were studied by considering the analytical solution of a spherical cavity embedded in full space as an example. Finally, two interaction systems were used to verify the applicability of the improved method in analyzing the soil–structure dynamic interaction.

Effect of SSI and Fixed-base Concept on the Dynamic Responses of Masonry Bridge Structures, Dalal Bridge as a Case Study

Historical masonry structures are very important as they carry cultural heritage, so it is important to protect these structures from natural disasters such as earthquakes and transferred to the next generations. It is known that masonry structures are weak against earthquakes, therefore, a suitable analysis method for assessment and retrofitting purposes is a must. Generally, the fixed-base concept is used for analysis and design purposes, however, in reality, the structures are not fixed-base but they are resting on soils. The aim of this study is to make a comparison study between dynamic responses of fixed-base and soil-structure interaction (SSI) models for bridge masonry structures, the historical Dalal bridge was selected as the case study. First, the bridge was modeled as a fixed base model, and then three different soil profiles (hard, medium and soft soils) were added to the underneath of the structure. The numerical models were analyzed under Elcentro earthquake record. Results indicating a good agreement between the fixed base and the case of hard soil base. However, considerable differences were observed for medium and soft soil profiles.