• Earthquakes and Structures
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• 제24권3호
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• pp.155-163
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• 2023

The purpose of this paper is to investigate the coupled effect of SSI and pounding on dynamic responses of unequal height adjacent buildings with insufficiently separation distance subjected to seismic loading. Numerical investigations were conducted to evaluate effect of the pounding coupling SSI on a Reinforced Concrete Frame Structure system constructed on different soil fields. Adjacent buildings with unequal height, including a 9-storey and a 3-storey reinforced concrete structure, were considered in numerical studies. Pounding force response, time-history and root-mean-square (RMS) of displacement and acceleration with different types of soil and separations were presented. The numerical results indicate that insufficient separation could lead to collisions and generate severe pounding force which could result in acceleration and displacement amplifications. SSI has significant influence of the seismic response of the structures, and higher pounding force were induced by floors with stiffer soil. SSI is reasonable neglected for a structure with a dense soil foundation, whereas SSI should be taken into consideration for dynamic analysis, especially for soft soil base.

• 한국지진공학회논문집
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• 제27권6호
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• pp.253-263
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• 2023

Non-structural elements, such as equipment, are typically affixed to a building's floor or ceiling and move in tandem with the structure during an earthquake. Seismic forces acting upon non-structural elements traverse the ground and the building's structure. Considering this seismic load transmission mechanism, it becomes imperative to account for the interactions between soil, structure, and equipment, establishing seismic design procedures accordingly. In this study, a Soil-Structure-Equipment Interaction (SSEI) model is developed. Through seismic response analysis using this model, how the presence or absence of SSEI impacts equipment behavior is examined. Neglecting the SSEI aspect when assessing equipment responses results in an overly conservative evaluation of its seismic response. This emphasizes the necessity of proposing an analytical model and design methodology that adequately incorporate the interaction effect. Doing so enables the calculation of rational seismic forces and facilitates the seismic design of non-structural elements.

• Geomechanics and Engineering
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• 제6권2호
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• pp.117-138
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• 2014

The main focus of the current study is to evaluate the dynamic behavior of a cantilever retaining wall considering backfill and soil/foundation interaction effects. For this purpose, a three-dimensional finite element model (FEM) with viscous boundary is developed to investigate the seismic response of the cantilever wall. To demonstrate the validity of the FEM, analytical examinations are carried out by using modal analysis technique. The model verification is accomplished by comparing its predictions to results from analytical method with satisfactory agreement. The method is then employed to further investigate parametrically the effects of not only backfill but also soil/foundation interactions. By means of changing the soil properties, some comparisons are made on lateral displacements and stress responses. It is concluded that the lateral displacements and stresses in the wall are remarkably affected by backfill and subsoil interactions, and the dynamic behavior of the cantilever retaining wall is highly sensitive to mechanical properties of the soil material.

• Structural Engineering and Mechanics
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• 제42권4호
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• pp.571-587
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• 2012

This paper presents results of a numerical analysis performed on a corrugated steel plate (CSP) bridge during a backfilling process. The analysed bridge structure was a box culvert having a span of 12315 mm as well as a clear height of 3550 mm. Obtained calculation results were compared with the experimental ones. The paper is presented with the application of the Fast Lagrangian Analysis of Continua (FLAC) program based on the finite differences method (FDM) to determine behaviour of the soil-steel bridge structure during backfilling. The assumptions of a computational 2D model of soil-steel structure with a non-linear interface layer are described. Parametric analysis of the interface element is also given in order to receive the most realistic calculation results. The method based on this computational model may be used with large success to design calculations of this specific type of structure instead of the conventional and fairly inaccurate analytical methods. The conclusions drawn from such analysis can be helpful mostly for the assessment of the behaviour of steel-soil bridge structures under loads of backfilling. In consideration of an even more frequent application of this type of structure, conclusions from the conducted analysis can be generalized to a whole class of similar structural bridge solutions.

• Journal of Microbiology and Biotechnology
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• 제32권10호
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• pp.1275-1283
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• 2022

Understanding soil microbial community structure in the Arctic is essential for predicting the impact of climate change on interactions between organisms living in polar environments. The hypothesis of the present study was that soil microbial communities and soil chemical characteristics would vary depending on their associated plant species and local environments in Arctic mature soils. We analyzed soil bacterial communities and soil chemical characteristics from soil without vegetation (bare soil) and rhizosphere soil of three Arctic plants (Cassiope tetragona [L.] D. Don, Dryas octopetala L. and Silene acaulis [L.] Jacq.) in different local environments (coal-mined site and seashore-adjacent site). We did not observe any clear differences in microbial community structure in samples belonging to different plant rhizospheres; however, samples from different environmental sites had distinct microbial community structure. The samples from coal-mined site had a relatively higher abundance of Bacteroidetes and Firmicutes. On the other hand, Acidobacteria was more prevalent in seashore-adjacent samples. The relative abundance of Proteobacteria and Acidobacteria decreased toward higher soil pH, whereas that of Bacteroidetes and Firmicutes was positively correlated with soil pH. Our results suggest that soil bacterial community dissimilarity can be driven by spatial heterogeneity in deglaciated mature soil. Furthermore, these results indicate that soil microbial composition and relative abundance are more affected by soil pH, an abiotic factor, than plant species, a biotic factor.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.249-256
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• 2006

New infrastructures and buildings are being constructed increasingly in congested urban areas, and excavation-induced ground movements often cause distortion and damage to adjacent buildings. Protection of adjacent structures occupies a major part of the cost, schedule and third-party impacts of urban development. To limit damage or mitigate their effects on nearby structures, it is highly important to understand the whole mechanism from excavation to building damage, and to estimate building damage reliably before excavation and provide appropriate measures. This paper investigates the effects of excavation-induced ground movements on nearby structures, considering soil-structure interactions for ground and structures, and a building damage criterion, which is based on the state of strain, is proposed. The criterion is compared with other existing damage estimation criteria and a procedure is finally provided for estimating building damage due to excavation-induced ground movements.

• Coupled systems mechanics
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• 제5권1호
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• pp.41-58
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• 2016

The study deals with physical modeling of a typical building frame resting on pile raft foundation and embedded in cohesive soil mass using finite element based software ETABS. Both- the elements of superstructure and substructure (i.e., foundation) including soil is assumed to remain in elastic state at all the time. The raft is modelled as a thin plate and the pile and soils are treated as interactive springs. Both- the resistance of the piles as well as that of raft base - are incorporated into the model. Interactions between raft-soil-pile are computed. The proposed method makes it possible to solve the problems of uniformly and large non-uniformly arranged piled rafts in a time saving way using finite element based software ETABS. The effect of the various parameters of the pile raft foundation such as thickness of raft and pile diameter is evaluated on the response of superstructure. The response included the displacement at the top of the frame and bending moment in columns. The soil-structure interaction effect is found to increase displacement and increase the absolute maximum positive and negative moments. The effect of the soil- structure interaction is observed to be significant for the type of foundation and soil considered in the present study.

• 한국토양비료학회지
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• 제44권3호
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• pp.517-526
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• 2011

Soil structure plays an important role in ecological system, since it controls transport and storage of air, gas, nutrients and solutions. The study of soil structure requires an understanding of the interrelations and interactions between the diverse soil components at various levels of organization. Investigations of the spatial distribution of pore/particle arrangements and the geometry of soil pore space can provide important information regarding ecological or crop system. Because of conveniences in image analyses and accuracy, these investigations have been thrived for a long time. Image analyses from soil sections through impregnated blocks of undisturbed soil (2 dimensional image analyses) or from 3 dimensional scanned soils by computer tomography allow quantitative assessment of the pore space. Image analysis techniques can be used to classify pore types and quantify pore structure without inaccurate or hard labor in laboratory. In this paper, the last 50 years of the soil image analyses have been presented and measurements on various soil scales were introduced, as well. In addition to history of image analyses, a couple of examples for soil image analyses were displayed. The discussion was made on the applications of image analyses and techniques to quantify pore/soil structure.

• Structural Engineering and Mechanics
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• 제54권3호
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• pp.491-500
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• 2015

Under seismic loading, underground station structures behave differently from above ground structures. Underground structures do not require designated energy dissipation system for seismic loads. These structures are traditionally designed with shear or racking deformation capacity to accommodate the movement of the soil caused by shear waves. The free-field shear deformation method may not be suitable for the design of shallowly buried station structures with complex structural configurations. Alternatively, a station structure can develop rocking mechanisms either as a whole rigid body or as a portion of the structure with plastic hinges. With a rocking mechanism, station structures can be tilted to accommodate lateral shear deformation from the soil. If required, plastic hinges can be implemented to develop rocking mechanism. Generally, rocking structures do not expect significant seismic loads from surrounding soils, although the mechanism may result in significant internal forces and localized soil bearing pressures. This method may produce a reliable and robust design of station structures.

• Geomechanics and Engineering
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• 제34권5호
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• pp.529-545
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• 2023

The coupled soil-pile-structure seismic response is recently in the spotlight of researchers because of its extensive applications in the different fields of engineering such as bridges, offshore platforms, wind turbines, and buildings. In this paper, a simple analytical model is developed to evaluate the dynamic performance of seismically isolated bridges considering triple interactions of soil, piles, and bridges simultaneously. Novel expressions are proposed to present the dynamic behavior of pile groups in inhomogeneous soils with various shear modulus along with depth. Both cohesive and cohesionless soil deposits can be simulated by this analytical model with a generalized function of varied shear modulus along the soil depth belonging to an inhomogeneous stratum. The methodology is discussed in detail and validated by rigorous dynamic solution of 3D continuum modeling, and time history analysis of centrifuge tests. The proposed analytical model accuracy is guaranteed by the acceptable agreement between the experimental/numerical and analytical results. A comparison of the proposed linear model results with nonlinear centrifuge tests showed that during moderate (frequent) earthquakes the relative differences in responses of the superstructure and the pile cap can be ignored. However, during strong excitations, the response calculated in the linear time history analysis is always lower than the real conditions with the nonlinear behavior of the soil-pile-bridge system. The current simple and efficient method provides the accuracy and the least computational costs in comparison to the full three-dimensional analyses.