Soil-structure Interaction Effects Research Articles

Effect of Soil Structure Interaction on Multi-Storeyed Building with Raft Foundation

This paper addresses the behaviour of multi storey structure considering soil structure interaction i.e. interaction between substructure of the building and soil. For this purpose a sample of 5 storey RC frames is analysed in conventional method with incremental static analysis for various load combinations and determines the parameters displacement, shear force and bending moment. Then a same 5 storey RC frame is analysed in numerical analysis using Finite Element Method (FEM) with raft foundation by assigning the soil properties to substructure and determine the parameters displacement, shear force and bending moment. According to the analysis results the parameters displacements, shear force and bending moment varies from conventional analysis to numerical analysis. Displacements of the structure increases, shear forces of the structure decreases and bending moment of the structure decreases at some points and increases at some points from conventional method of analysis to numerical method of analysis.

Coupled‐two‐beam discrete model for dynamic analysis of tall buildings with tuned mass dampers including soil–structure interaction

SummaryAn equivalent coupled‐two‐beam discrete model is developed for time‐domain dynamic analysis of high‐rise buildings with flexible base and carrying any number of tuned mass dampers (TMDs). The equivalent model consists of a flexural cantilever beam and a shear cantilever beam connected in parallel by a finite number of axially rigid members that allows the consideration of intermediate modes of lateral deformation. The equivalent model is applied to a shear wall–frame building located in the Valley of Mexico, where the effects of soil–structure interaction (SSI) are important. The effects of SSI and TMDs on the dynamic properties of the shear wall–frame building are shown considering four types of soil (hard rock, dense soil, stiff soil, and soft soil) and two passive damping systems: a single TMD on its top (1‐TMD) and five uniformly distributed TMDs (5‐TMD). The results showed a great effectiveness of the TMDs to reduce the lateral seismic response and along‐wind response of the shear wall–frame building for all types of soils. Generally speaking, the dynamic response increases as the flexibility of the foundation increases.

Seismic drift response of seesaw-braced and buckling-restrained braced steel structures: A comparison study

A numerical comparison study of the interstorey and the residual interstorey seismic drifts of steel structures equipped with the seesaw system and buckling-restrained braces is carried out. This investigation involves inelastic time-history seismic analyses of 2-, 5- and 8-storey 3-D steel structures, with specific orientation of columns and configuration of braces, for the design basis earthquake. The effects of soil-structure interaction and seismic incident angle are also considered in these analyses. Comparison of the seismic drift responses experienced by the seesaw-braced and the buckling-restrained braced steel structures, reveals different peak interstorey drift values but in many cases similar drift concentration along the height of the structures. Furthermore, the seesaw-braced steel structures exhibit, in general, larger peak residual drifts than buckling-restrained braced steel structures.

Effects of soil-structure interaction on base-isolated structures

Structural integrity and seismic protection of the buildings against earthquake have been challenging among structural engineers. Many studies have been devoted to development of seismic isolators to improve the seismic behavior of civil structures. This study presents the analysis of building structures with SAP2000 considering soil structure interaction and base isolation effects under El Centro. Four different models are analyzed including fixed base structure, base isolated structure, frame supported by spring representing the soil and structure with combined base isolation and spring. The seismic results are investigated in terms of displacement, shear force, axial force, moment and drift of the columns and beams. It was observed that the soil structure interaction provides some flexibility to the structure by increasing the displacements of the structure and imposing internal forces variation to the system. Therefore, modeling base isolation together with consideration of soil structure interaction leads to better prediction of structural response.

Seismic Evaluation of Flexible-Base Low-Rise Steel Frames Using Beam-On-Nonlinear-Winkler-Foundation Modeling of Shallow Footings

Recent studies have revealed that the influences of Soil-Structure Interaction (SSI) can be detrimental to the seismic behavior of structure, and hence ignoring this phenomenon in analysis and design may result in to an un-conservative design. The aim of this paper is to quantify the effects of nonlinear SSI on the seismic response of a low-rise special moment frame subjected to a family of ground motions with three hazard levels. To this end, seismic behavior of a 5-story special steel frame founded on linear and nonlinear flexible-base foundations are compared to the conventional fixed-base frame counterpart. The well-known Beam-on-Nonlinear-Winkler-Foundation (BNWF) approach is employed to model nonlinear soil-shallow foundation. Nonlinear static and time history dynamic analyses were conducted applying the OPENSEES platform in order to inquire the effect of modeling and ground motion parameters on their seismic performance. The results manifested some degrees of inaccuracy in the fixed-base and linear SSI assumptions when compared to its nonlinear flexible-base counterpart. Moreover, it is also found that disregarding the foundation flexibility effect may lead to over prediction of the inter-story drift, force and ductility demands of the low-rise steel structure.

Unfavourable seismic behaviour of reinforced concrete structures due to soil structure interaction

The soil-structure interaction (SSI) effects can substantially alter the behaviour of structures during earthquakes. Implementation of SSI within the seismic analysis often leads to lower stresses in the structure and therefore a more economical design. The recently introduced provisions in European and American codes allow for this type of approach. However, consideration of SSI can also lead to the observation of unfavourable effects (undetectable in a fixed-base analysis) due to the modification of the structure’s dynamic properties. Examples of unfavourable effects include higher global displacements or story drifts, increases of the base or story shear forces, higher post-elastic demands in the structural members or the collision of adjacent buildings separated by an insufficient structural joint. These unfavourable effects can be related to various parameters such as the structural system (frames or shear walls), foundation type (shallow or piles), geometry of the foundation, height of the building, soil type, seismic input, presence of adjacent buildings, etc. Under these circumstances, the integration of SSI into the current structural design becomes essential. As the mathematical formulation of the phenomenon is very complex and involves many parameters, the definition of complete numerical models is difficult. The provisions in the codes are often general and do not give the practicing engineers clear modelling solutions. An analysis of the current situation in the field of SSI is carried out, with a focus on the design of reinforced concrete structures. Based on an extensive literature review, the unfavourable seismic effects and the main parameters that determine them are identified. Conclusions are drawn regarding the situations when SSI should be mandatory and on the different possibilities of implementing SSI in the structural design.

Effect of Lateral Loads and Soil Structure Interface on Structural Performance of RCC Chimney

Chimneys are distinguished requirements for Power generation and other Manufacturing areas which are vital to be constructed vertically to discharge combustion gases and chemical waste gases to the environment. Due to the hasty growth of mechanization and escalating the requirement to control of Air pollution, the construction of tall Chimneys becomes a regular structure in contemporary circumstances. Tall chimney shells generally designed to resist vertical and lateral loads especially due to the effect of Wind and Earthquake. RCC Chimney shell will transfer these vertical and lateral loads to its foundation system. Soil Structure Interaction (SSI) is the response of soil which impacts the behavior of the structure or behavior of the structure which affects on response of soil. Soil Structure Interaction is essential for tall structures which especially resting on soft soil strata. This review work presents a widespread appraisal of the research presented in the area of RCC chimney and communicates most recent enlightenments and improvements happened in the analysis and design. This paper makes an attempt on focusing the modeling features of RCC chimneys which contains analysis, design aspects and several case studies, with the help of various software programs with the effects of lateral loads and soil structure interaction. The present review paper also corresponds to a complete anthology of the research accomplished on RCC chimney and will gives rationalized technical information for the researchers.

Probabilistic Evaluation of Soil–Structure Interaction Effects on Strength Demands of Shear Buildings

This paper revisited the effect of soil–structure interaction (SSI) on the nonlinear response of multistory buildings with a probabilistic approach. In particular, this study showed that the magnitude of SSI effects on the strength demand of a multiple-degree-of-freedom (MDOF) system stems from the effect of SSI on the corresponding equivalent single-degree-of-freedom (eSDOF) system. This seems to negate several past studies on flexible-base MDOF systems. In fact, such studies did not quantify the split between contributions of SSI effects to the corresponding eSDOF system and to those unique aspects of MDOF systems that cannot be represented by the eSDOF system. Doing so in the present paper showed that the effect of SSI on the inelastic response of MDOF systems can be well predicted based on the knowledge of the SSI effect on the response of SDOF systems, i.e., the share of MDOF aspects of the system in this effect is insignificant. Based on this finding, a procedure is proposed to determine the strength demand of a flexible-base shear building given a target ductility demand.

Application of the internal substructure method for seismic wave input in structural dynamic analysis considering SSI effect

A new internal substructure method for seismic wave input in soil-structure systems was proposed very recently. This method simplifies the calculation of equivalent input seismic loads, and avoids the participation of artificial boundaries in the process of seismic wave input. In this study, we introduce the application of the internal substructure method in the structural seismic analysis considering soil-structure interaction (SSI). A typical frame structure is taken as the example, and the effect of SSI on the structural dynamic response is studied.

Seismic response of low-rise 3-D steel structures equipped with the seesaw system

The efficiency of the seesaw system when applied to low-rise 3-D steel structures is presented in this paper. This efficiency is judged by several seismic response results coming from inelastic seismic time-history analyses of 2-, 5- and 8-storey steel structures. These response results involve height wise distributions for peak interstorey drift ratios (IDR), peak residual interstorey drift ratios (RIDR) and plastic hinge formations in frame elements as well as peak forces to spiral strand ropes and viscous dampers of the seesaw system. For the foundation of the steel structures, different soil types are considered in order to assess the effects of soil-structure interaction (SSI). The seismic incident angle is also taken into account. From the results presented it is concluded that the seesaw system, essentially working always in tension, constitutes a bracing solution that can be potentially proposed by seismic codes as an alternative seismic force resisting system for low-rise steel structures.

Assessment of dynamic soil-structure interaction effects for tall buildings: A 3D numerical approach

Soil-structure interaction (SSI) phenomena are typically studied in the frequency-domain using the substructure approach, involving several simplifications. In this study, SSI effects for a 20-storey building are studied numerically performing time-domain 3D non-linear dynamic analyses, using an elastoplastic nonlinear constitutive model for the soil. Three foundation systems - a relatively shallow, a deeply embedded and a pile foundation - and two soil profiles are investigated and compared. Specifically, relative merits of site amplification, kinematic interaction and inertial interaction are isolated, and the role of foundation deformability and local stratigraphy is highlighted. To isolate such features, the results of the complete 3D models are compared with those provided by 3D numerical analyses of the sole building, of the foundation-soil systems and of the free-field soil deposit.Numerical results show that, for tall buildings, an increase in foundation deformability leads to a decrease of the maximum base shear force (seismic demand), to a higher rigid rotation of the foundation, but not to appreciably higher displacements of the structure. Moreover, possible situations where a (decoupled) substructure approach can lead to a misinterpretation of SSI phenomena are highlighted, as in the case of deep foundations crossing very soft soil layers.In addition, the use of embedded pile elements was proven to be an effective strategy in reducing the computational cost when performing complex 3D simulations of dynamic SSI problems.

Influence of soil\u2013structure interaction on seismic pounding between steel frame buildings considering the effect of infill panels

The present research aims to study the influence of the soil–structure interaction (SSI) and existence or absence of masonry infill panels in steel frame structures on the earthquake-induced pounding-involved response of adjacent buildings. The study was further extended to compare the pounding-involved behavior versus the independent behavior of structures without collisions, focusing much on dynamic behavior of single frames. The effect of SSI was analyzed by assuming linear springs and dashpots at the foundation level. The infill panels were modeled using equivalent diagonal compression struts. The steel frames were assumed to have elastic–plastic behavior with 1% linear strain hardening. The dynamic contact approach was utilized to simulate pounding between the adjacent buildings. Nonlinear finite element analysis was performed for two adjacent multi-story structures with four different configurations representing cases that can exist in reality. The seismic response of the studied cases generally emphasized that ignoring the soil flexibility and/or the contribution of the infill panels may significantly alter the response of adjacent structures. This may result in a false expectation of the seismic behavior of buildings exposed to structural pounding under earthquake excitation.

Construction of a concrete segmental arch bridge over a railway

This paper describes the modelling of the behaviour of a large precast concrete segmental arch structure during construction over a main line railway. The main aim of the modelling was to accurately predict the deflections of the segmental arch during construction and to set trigger levels to prevent another failure similar to that which occurred at Gerrards Cross, UK. The failure at Gerrards Cross, reported in 2005, demonstrated the importance of controlling the backfill and carefully controlling and monitoring the deflections of the arch during construction. To enable accurate predictions, finite-difference analysis of the precast segmental structure was utilised, which takes account of the soil–structure interaction effects covering structure and soil stiffness. Many sensitivity analyses were necessary to predict lower and upper bounds using predominant parameters that influenced the behaviour and included the movement of the arches on the piled foundations. Observations taken on site of movements of the arch during construction showed that actual deflections matched the predicted movements to a very high degree.

Effects of Soil-Structure Interaction on the Inelastic Seismic Response of Continuous Bridges on Piled Foundation

Effect of soil-structure interaction (SSI) on seismic response of bridges is not clearly understood, and in general practice, bridge design is carried out ignoring its effect. This is due to the general consensus that fixed base leads to a more conservative design despite the fact that many researchers indicate that ignoring soil-structure interaction may lead to underestimation of seismic response. The current paper aims to investigate the effect of SSI on the nonlinear seismic behavior of 9-span continuous bridge supported on pile foundation penetrating sandy soils. Three types of soils were investigated representing medium to stiff sandy soil. Both pushover analysis and nonlinear time history incremental dynamic analysis are carried out using Opensees to investigate the effect of SSI on the seismic response parameters (namely, fundamental period, pushover curves, foundation rigid body motions, global ductility capacity and demand, and maximum drift ratio) of the bridge and to compare it to fixed base assumption (i.e., SSI ignored). The results indicate that although SSI increases the flexibility of the structure (accordingly increasing fundamental period), the seismic demand of the bridge increases. This increase is more pronounced as the soil becomes softer.

Simulation analysis of TMD controlled building subjected to far- and near-fault records considering soil-structure interaction

This study aims to investigate the performance of a tuned mass damper (TMD) in mitigating the dynamic response of buildings to far- and near-fault earthquake records including soil–structure interaction (SSI) effects. The selected records ensure near-fault with forward directivity (FD) and near-fault with fling. The effects of certain parameters of the installed TMD, such as the mass, the frequency and the damping ratios have been investigated using a developed MATLAB code. Displacement, velocity, acceleration, and energy responses from the analysis of the building model subjected to each of the considered faults were numerically calculated. The obtained numerical simulation results for the cases without and with including the SSI effects are comparatively presented and evaluated for the building model with a TMD damper. The presented results clearly show that there is a more seismic demand on an induced response for buildings excited by near fault records with fling. In addition, the inclusion of SSI increases the induced responses and alters the role of TMD in reducing the superstructure responses.

Seismic Behavior Analysis Considering Soil Structure Interaction of RC Multistory Buildings in Halabja City

Response of structures to seismic loads measures the degree of safety of the structures. In order for buildings to be under a more realistic circumstance, it is essential to consider the effect of Soil – Structure – Interaction (SSI) in the analysis of the building subjected to seismic loads. In this study, three samples of typical buildings with six, eight and ten stories are chosen with and without the effect of SSI using both equivalent static method and dynamic response spectrum analysis. For each method, the five different soil categories (SA, SB, SC, SD, SE) are examined to illustrate the effect of the foundation soil on the buildings subjected to a seismic load. The results show that no modifications can be observed in rock foundations with or without the consideration of SSI. On the contrary, the effect on SSI can increase the displacement in low stiffness soils particularly soil type (SE). Similarly the natural time period of the buildings increase significantly with decreasing the soil stiffness.&nbsp

Modified Tuned Liquid Dampers for Seismic Protection of Buildings Considering Soil–Structure Interaction Effects

Considering the effect of soil–structure interaction in dynamic analysis of structures can change their responses. It is generally assumed that the structure is located on a rigid foundation and the flexibility effect of the soil is not considered. Researches on the soil–structure interaction show that the dynamic response of the structures located on a soft and flexible soil is completely different from the dynamic response of the same structure located on a stiff soil. In this paper, the effect of the soil–structure interaction on the response of a single-degree-of-freedom system (Nagasaki airport tower) that is controlled by a modified tuned liquid damper is investigated. The soil effect is modeled using an approximate cone method based on the semi-infinite boundary conditions. First, the governing equations for describing the fluid sloshing obtained with shallow water wave theory are solved by Lax’s finite-difference scheme. Then, the dynamic equilibrium equations for a structure controlled with a modified tuned liquid damper are obtained by considering the effect of soil–structure interaction using Lagrange’s method. These equations are solved numerically by Newmark’s method. The controlled structural responses are calculated in different time steps and compared with the responses of the uncontrolled structure. Results show that the seismic design of the modified tuned liquid damper system can be more effective to reduce the structural responses. Also, this system can reduce efficiently the maximum responses of the structures considering soil–structure interaction effect during a near-fault earthquake.

Application of Spectral Element Method for Dynamic Analysis of Plane Frame Structures

The paper presents a methodology to analyze plane frame structures using the Spectral Element Method (SEM) with and without considering Soil-Structure Interaction (SSI). The formulation of spectral element matrices based on higher-order element theories and the assemblage procedure of arbitrarily oriented members are outlined. It is shown that SEM gives more accurate results with much smaller computational cost, especially at high frequencies. Since the formulation is in the frequency domain, the frequency-dependent foundation impedance functions and SSI effects can easily be incorporated in the analysis. As an example, the dynamic response of a plane frame structure is calculated based on the Finite Element Method (FEM) and SEM. FEM and SEM results are compared at different frequency bands, and the effects of SSI on the dynamic response are discussed.

An investigation into the effect of soil-foundation interaction on the seismic performance of tunnel-form buildings

Great weight and stiffness can potentially intensify the forces induced to the tunnel-form buildings during seismic events. To overcome the adverse effects of these two parameters on the seismic reliability of buildings benefitting from this structural system, it appears critically essential to account for the soil-structure interaction (SSI) in the modeling process. Accordingly, this paper aims to assess the level of seismic performance as well as the safety condition of buildings against sliding and overturning phenomena. For this purpose, the soil underlying two tunnel-form buildings with 5 and 10 stories was modeled using the linear springs and then, the analysis results were captured for two cases of rigid and flexible base. Based on the results, as the building height and earthquake intensity increases, the SSI effects on the structural responses such as the shear forces and storey drifts and location of damage initiation became profounder. Comparatively, probability of reaching the primary damage levels along with sliding and overturning increased by at least 30 and 10%, respectively in the case of flexible base. In sum, it is concluded that in seismically active areas formed by soft soil, the SSI effect can hinder tall buildings from achieving the predefined performances.

Topographic effects during the September 19, 2017 Mexico city earthquake

Seismic waves can significantly amplify in firm soil with abrupt geometric changes due to topographic effects. Moreover, nonlinearities associated with soil layering and geometrical interactions of the incoming waves can lead to changes in frequency content and duration. This paper presents a case study of the effects of the September 19, 2017 earthquake, in the seismic response of a building-hill system 60 m high located in the western part of Mexico City. The performance of the building-hill system was evaluated for this event accounting for site response, topographic, and soil-structure interaction effects, using three-dimensional finite difference models developed with the program FLAC3D. From the numerical study, the seismic response of the slope was evaluated, accounting for the seismic building-hill interaction effect in the distribution of factors of safety (i.e. capacity over demand), and ground deformations during the event. The damage predicted by the numerical simulation in the building and the hill slope during the 2017 earthquake was in good agreement with that observed during post-earthquake site reconnaissance. To study the effects of the frequency content, seismic intensity, and duration in the distribution of factor of safety and slope deformation patterns, the building-hill seismic response was further studied for subduction and normal events, considering uniform hazard spectra with return period of 250 years. From the results gathered in here, a clear dependency of the expected damage on the hill slope as a function of the seismogenic zone (i.e. subduction or normal) was observed.