https://www.db-thueringen.de/receive/dbt_mods_00069367https://www.db-thueringen.de/servlets/MCRFileNodeServlet/dbt_derivate_00070790/Bapir_2025_Evaluating_the_Impacts_of_Dynamic_Soil_Structure_Interaction_on_the_Seismic_Resilience_of_Reinforced_Concrete_Buildings_Using_Simplified_and_Advanced.pdfhttps://www.db-thueringen.de/rsc/thumbnail/dbt_mods_00069367.png thesis text thesis Impacts of Dynamic Soil-Structure Interaction on the Seismic Resilience of Reinforced Concrete Structures through a Multi-Model Analysis aut Author Bapir, Baban Abdulwahid 0000-0002-4429-6419 Bapir Baban Abdulwahid ths Thesis advisor Abrahamczyk, Lars 0000-0002-1217-3844 Abrahamczyk Lars 10.25643/dbt.69367 urn:nbn:de:gbv:wim2-dbt-69367-3 Abrahamczyk, Lars rev Reviewer 0000-0002-1217-3844 Abrahamczyk Lars 2025-10-07 Weimar 2024-10-15 2025 2025-07-17 Faculty of Civil and Environmental Engineering, Institute of Structural Engineering (IKI), Chair of Advanced Structures Bauhaus-Universität Weimar xxix, 301 Pages en 624 690 620 The seismic response of structures influenced by soil-structure interaction (SSI) has gained significant attention as a topic of study in recent decades. This interaction, where both soil and structural dynamics influence each other during an earthquake, brings complexities that greatly influence the behaviour and performance of the structure. Previous studies have extensively investigated this phenomenon under the assumption of elastic behaviour for both the superstructure and the subsoil. However, this assumption may not hold in many real-world situations, especially during strong earthquake events where inelastic behaviour is prominent. Structures often undergo inelastic deformations, and soils show nonlinear behaviour even under weak to moderate seismic loads. Ignoring the inelastic properties of both soil and structures in SSI studies can lead to misleading conclusions and inaccurate assessments of seismic performance and potential damages. Therefore, a comprehensive understanding of both elastic and inelastic responses in seismic SSI is essential for accurate seismic analysis and design. In the present study, a multi-model analysis approach is adopted to thoroughly investigate the critical impacts of SSI on the seismic response of building structures and to evaluate the performance of various modelling techniques. The simplified SSI models comprise two linear models (Cone and Gazetas model) and one nonlinear model, known as the Beam on Nonlinear Winkler Foundation (BNWF). The analysis begins by examining the SSI influences on the inelastic response and ductility demand of several bare-frame buildings with varying heights and geometries. According to the findings, SSI induces a notable increase in lateral drift and deflection of the structures, while the total base shear force is reduced compared to fixed base structures. This increase in lateral deflection has led to an extra deformation and ductility demand in the structural members. The study further differentiates the response behaviours between linear and nonlinear SSI models and emphasises the importance of model selection in conducting dynamic SSI studies. To extend the investigations, a sophisticated 3-dimensional Finite Element (FE) model is developed in ABAQUS to simulate seismic SSI. The Clay Hypoplasticity soil constitutive model is incorporated into the numerical model framework to accurately represent the fully nonlinear behaviour of the soil under earthquake loading. The numerical model is verified against experimental results and serves as a benchmark model to evaluate the performance of the three simplified SSI models in capturing various structural responses under different earthquake intensities. The findings reveal that while linear SSI models provide useful insights at lower seismic amplitudes, their limitations become notable at higher amplitudes. Among the evaluated models, the nonlinear BNWF model demonstrated a better performance in capturing the overall responses. Hence, the necessity of integrating nonlinear soil behaviour in SSI simulations is emphasised. The study further progresses to improve the capability of the linear SSI models by integrating nonlinear soil effects. This enhancement involves estimating the soil deformation under the foundation in the nonlinear FE model based on the maximum strain level experienced during seismic events. From these strain levels, adjustments are made to the soil’s shear modulus and damping properties, which are then integrated into the linear SSI models. The results indicate a significant improvement in the Gazetas model in predicting the seismic response of the building, which aligns more closely with the outcomes observed in the FE results. The Cone model also shows notable enhancement, although to a smaller degree compared to the Gazetas model. A key contribution of this study is the development of an Equivalent Linear Spring-Dashpot (ELSD) model to simulate nonlinear SSI under seismic actions. This model represents an innovative adaptation of the Gazetas model, which is specifically designed to address nonlinear soil behaviour through an equivalent linear approach. The ELSD model is particularly developed for SSI analysis of structures on soft and stiff clay soil deposits under various earthquake intensities. The standout feature of the ELSD model lies in its straightforward methodology for defining nonlinear soil behaviour. By using only two key parameters (effective peak ground acceleration and shear wave velocity of the soil) the model simplifies the complex nature of nonlinear soil behaviour while preserving a high level of accuracy. The performance of the model is evaluated for a wide range of SSI simulations on soft soil deposits under various ground motions with different frequency contents. The analysis results demonstrated the remarkable efficiency and accuracy of the ELSD model, which can be used as a reliable and practical tool for seismic SSI analysis. Finally, the study extends its investigation to the impact of SSI on the seismic response of Unreinforced Masonry (URM) infill walls within the context of low and medium-height RC structures. The analysis considers both in-plane (IP) and out-of-plane (OoP) behaviours of the infills. It employs the auto-element removal algorithm to simulate the collapse of infill walls during seismic events. This algorithm enhances the accuracy of the damage predictions by allowing the dynamic analysis to account for the progressive failure of infill walls. The investigations demonstrate the critical influences of SSI on the amplification of structural lateral deflections and damage states of the infills, particularly in taller structures. The study also highlights the role of OoP deformation in contributing to infill collapse in SSI models, which is not prominent in fixed-base models. The overall insights from this study underscore the critical need to integrate SSI considerations in design methodologies to mitigate the risks associated with infill wall damage and ensure the safety and resilience of structures. rev Reviewer Wichtmann, Torsten 0000-0002-9250-7014 Wichtmann Torsten Davorin, Penava rev Reviewer 0000-0001-7539-4639 Davorin Penava his Host institution bibliography thesis text Impacts of Dynamic Soil-Structure Interaction on the Seismic Resilience of Reinforced Concrete Structures through a Multi-Model Analysis thesis aut Author Bapir, Baban Abdulwahid 0000-0002-4429-6419 Bapir Baban Abdulwahid ths Thesis advisor Abrahamczyk, Lars 0000-0002-1217-3844 Abrahamczyk Lars Abrahamczyk, Lars rev Reviewer 0000-0002-1217-3844 Abrahamczyk Lars 10.25643/dbt.67576 2025-10-07 Weimar urn:nbn:de:gbv:wim2-dbt-67576-6 2024-10-15 2025 2025-07-17 Faculty of Civil and Environmental Engineering, Institute of Structural Engineering (IKI), Chair of Advanced Structures Bauhaus-Universität Weimar xxix, 301 Pages en 624 690 620 The seismic response of structures influenced by soil-structure interaction (SSI) has gained significant attention as a topic of study in recent decades. This interaction, where both soil and structural dynamics influence each other during an earthquake, brings complexities that greatly influence the behaviour and performance of the structure. Previous studies have extensively investigated this phenomenon under the assumption of elastic behaviour for both the superstructure and the subsoil. However, this assumption may not hold in many real-world situations, especially during strong earthquake events where inelastic behaviour is prominent. Structures often undergo inelastic deformations, and soils show nonlinear behaviour even under weak to moderate seismic loads. Ignoring the inelastic properties of both soil and structures in SSI studies can lead to misleading conclusions and inaccurate assessments of seismic performance and potential damages. Therefore, a comprehensive understanding of both elastic and inelastic responses in seismic SSI is essential for accurate seismic analysis and design. In the present study, a multi-model analysis approach is adopted to thoroughly investigate the critical impacts of SSI on the seismic response of building structures and to evaluate the performance of various modelling techniques. The simplified SSI models comprise two linear models (Cone and Gazetas model) and one nonlinear model, known as the Beam on Nonlinear Winkler Foundation (BNWF). The analysis begins by examining the SSI influences on the inelastic response and ductility demand of several bare-frame buildings with varying heights and geometries. According to the findings, SSI induces a notable increase in lateral drift and deflection of the structures, while the total base shear force is reduced compared to fixed base structures. This increase in lateral deflection has led to an extra deformation and ductility demand in the structural members. The study further differentiates the response behaviours between linear and nonlinear SSI models and emphasises the importance of model selection in conducting dynamic SSI studies. To extend the investigations, a sophisticated 3-dimensional Finite Element (FE) model is developed in ABAQUS to simulate seismic SSI. The Clay Hypoplasticity soil constitutive model is incorporated into the numerical model framework to accurately represent the fully nonlinear behaviour of the soil under earthquake loading. The numerical model is verified against experimental results and serves as a benchmark model to evaluate the performance of the three simplified SSI models in capturing various structural responses under different earthquake intensities. The findings reveal that while linear SSI models provide useful insights at lower seismic amplitudes, their limitations become notable at higher amplitudes. Among the evaluated models, the nonlinear BNWF model demonstrated a better performance in capturing the overall responses. Hence, the necessity of integrating nonlinear soil behaviour in SSI simulations is emphasised. The study further progresses to improve the capability of the linear SSI models by integrating nonlinear soil effects. This enhancement involves estimating the soil deformation under the foundation in the nonlinear FE model based on the maximum strain level experienced during seismic events. From these strain levels, adjustments are made to the soil’s shear modulus and damping properties, which are then integrated into the linear SSI models. The results indicate a significant improvement in the Gazetas model in predicting the seismic response of the building, which aligns more closely with the outcomes observed in the FE results. The Cone model also shows notable enhancement, although to a smaller degree compared to the Gazetas model. A key contribution of this study is the development of an Equivalent Linear Spring-Dashpot (ELSD) model to simulate nonlinear SSI under seismic actions. This model represents an innovative adaptation of the Gazetas model, which is specifically designed to address nonlinear soil behaviour through an equivalent linear approach. The ELSD model is particularly developed for SSI analysis of structures on soft and stiff clay soil deposits under various earthquake intensities. The standout feature of the ELSD model lies in its straightforward methodology for defining nonlinear soil behaviour. By using only two key parameters (effective peak ground acceleration and shear wave velocity of the soil) the model simplifies the complex nature of nonlinear soil behaviour while preserving a high level of accuracy. The performance of the model is evaluated for a wide range of SSI simulations on soft soil deposits under various ground motions with different frequency contents. The analysis results demonstrated the remarkable efficiency and accuracy of the ELSD model, which can be used as a reliable and practical tool for seismic SSI analysis. Finally, the study extends its investigation to the impact of SSI on the seismic response of Unreinforced Masonry (URM) infill walls within the context of low and medium-height RC structures. The analysis considers both in-plane (IP) and out-of-plane (OoP) behaviours of the infills. It employs the auto-element removal algorithm to simulate the collapse of infill walls during seismic events. This algorithm enhances the accuracy of the damage predictions by allowing the dynamic analysis to account for the progressive failure of infill walls. The investigations demonstrate the critical influences of SSI on the amplification of structural lateral deflections and damage states of the infills, particularly in taller structures. The study also highlights the role of OoP deformation in contributing to infill collapse in SSI models, which is not prominent in fixed-base models. The overall insights from this study underscore the critical need to integrate SSI considerations in design methodologies to mitigate the risks associated with infill wall damage and ensure the safety and resilience of structures. rev Reviewer Wichtmann, Torsten 0000-0002-9250-7014 Wichtmann Torsten Davorin, Penava rev Reviewer 0000-0001-7539-4639 Davorin Penava his Host institution Die Dissertation ist parallel in der Schriftenreihe des Instituts für konstruktiven Ingenieurbau erschienen. keine Übertragung an HSB, Freigabe entfernt 13.3.26 and. 39 text Schriftenreihe des Instituts für Konstruktiven Ingenieurbau series Weimar Universitätsverlag de 620 his Host institution Bauhaus-Universität Weimar. Institut für Konstruktiven Ingenieurbau isb Issuing body 2150734-X 1431163411727100360000 Die Dissertation ist als Band 39 in der Schriftenreihe des Instituts für konstruktiven Ingenieurbau erschienen. dbt_mods_00069367https://www.db-thueringen.de/receive/dbt_mods_00069367